JANUARY 2015
Contents
1. 29 EDN Europe JANUARY 2015 product Reference design for high power LED lighting mproving efficiency size and reliability of LED streetlights and high bay lighting the RDR 382 reference design describes a constant current 43V nominal 150W reference power supply for 90 265 VAC solid state lighting using Power Integrations HiperPFS 2 PFC controller ICs and HiperLCS integrated LLC power stage ICs Traditional dual stage drivers with separate PFC and LLC stages produce a constant voltage CV output requiring multiple DC DC converters to convert the output to constant current CC In contrast RDR 382 uses a novel feedback and control scheme which enables the LLC to provide constant cur rent directly at the output Multi function MEMS sensor integrates gas sensor his environmental sensor from Bosch Sensortec combines pressure humidity temperature and indoor air quality measurement param eters You can use it to equip mobile devices and wearables with indoor air quality measurement with its low power consumption and small pack age BME680 integrates a gas sensor with full specifications air pres sure humidity and ambient air temperature sensing functions in a single 3 0 x 3 0 mm footprint The gas sensor within the BME680 can detect a broad range of gases in order to measure indoor air quality for personal well being including Volatile Organic Compounds VOC peas oO from paints www edn europe c2. The usual technique of manually grinding the markings e off is time consuming and is liable to dam MS age components and A stress solder joints MMM Escatec has solved Bun Riail this problem by using its existing CO2 laser marker that was initially installed to change the surface structure of solder resist to give a clear and permanent marking on the surface of PCBs We found that using the laser to burn on a sea of numbers pat tern on the tops of the compo nents made sure that none of the manufacturers original markings can be read explained Martin rie n 1 e gt A hall i Xx e a Muendlein Engineering Manager at Escatec There is no damage or stress and the laser is very fast and accurate to within 0 1mm Complete i article here www edn europe com Chipset measures complete set of 3 phase AC power parameters Analog Devices has posted details of a chipset specifically designed for measuring 3 phase electrical DIGITAL INTERFACE IM PHASE C ADE79321 p ADE7933 vpo energy using shunts as current sensors The chipset comprises the ADE7978 the ADE7933 ADE7932 and ADE7923 ADE7933 ADE7932 are isolated 3 channel sigma delta analogue to digital converters 2 A ADCs for polyphase energy metering applications that use shunt current sensors The ADE7923 is a non isolated 3 channel 2 A ADC for the neutral line that uses a shunt 11 EDN Europe
3. a SEPIC converter has an additional inductor L2 and an ad ditional AC coupling capacitor C In a SEPIC converter the average inductor current of L1 equals the input current I whereas the aver age inductor current of L2 equals the output current lur In contrast the single inductor in an inverting buck boost converter has an average current of lour The coupling capacitor sees significant root mean square RMS current relative to both input current and output current which generates extra power loss and reduces the converter s overall ef ficiency To reduce power loss ceramic capacitors with low equivalent series resistance ESR are desired which usually leads to higher cost The additional inductor of a SEPIC converter coupled with the extra cou pling capacitor increases PCB size and total solution cost A coupled inductor can be used to replace two separate inductors to reduce PCB size However the selection of off the shelf coupled inductors is limited when compared to separate inductors Sometimes a custom design will be required which increases cost and lead time The continuation of this article discusses the two switch buck boost converter and its optimisation click below for the full article pdf download D Find non inverting buck boost on EETsearch D9 Messe Miinchen International oe a The No 1 Event for Printed Electronics Connecting Global Competence Exhibition March
4. 4 5 2015 Conference March 3 5 2015 Messe Munchen Germany NI ZAR We Build the Market gS i ba Ko olst Centre DS 0 O Thin Film Electronics ASA Daimler AB BASF SE middle H www lopec com 7th International Exhibition and Conference for the Printed Electronics Industry Analog Tips A 15 W PRECISION DIFFERENCE AMPLIFIER WITH THERMAL SHUTDOWN his precision amplifier can source or sink 1A making it ideal for high power applica tions such as component stereos self powered speakers and home theatres Many applications require both high precision and high output current A simple way to provide both is to combine a precision amplifier with a power amplifier Placing an ADA4870 high power amplifier inside the feedback loop of an AD8271 precision difference amplifier allows the circuit to pro vide the high output current of the ADA4870 while maintaining the DC precision of the AD8271 The output buffer can easily source 1A the high precision low distortion preamp with trimmed on chip resistors provides lower gain drift and gain error and higher com mon mode rejection than discrete 10k 10k 10k 10k ada4870 Vout 1210 1210 NA Figure 1 High power difference amplifier ture reduces the quiescent current to approximately 750 pA Simply pull the shutdown pin low and the circuit turns off High output current amplifie
5. By Ilija Uzelac amp Ron Reiserer This Design Idea presents a simple prov en reliable and robust method for charging large capacitor banks using a series connec tion of power MOSFETs to raise the breakdown voltage over that of an individual MOSFET When a power supply drives a large capacitive load the inrush current if not limited can reach tens or hundreds of amps for a high voltage power supply In general maximal ratings of a power supply could be transiently exceeded by many times but this is generally acceptable when the transient lasts a few AC line cycles This is typical for load capacitances up to a couple of hundred microfarads but for load capacitances in thousands of microfarads an inrush current limiter is a must Using MOSFETs as voltage controlled current elements is very suitable for capacitor charging circuit design Consider though If a task speci fies charging a capacitor bank with 1A from rectified AC mains of 240V a design with a sin gle P MOSFET would require that at power on the MOSFET pass 1A when its drain to source voltage V is about 330V which exceeds the safe operating area of most parts For example the IXTQ10P50P at the maximum junction tem 24 EDN Europe JANUARY 2015 perature of 150 C can handle 200 mA when IV s 250V but over 2A when VDS lt 100V This limitation can be overcome by connecting multiple P MOSFE Ts in series QI MMBT3906 Unregulated rectified 240
6. Vrms IXTOLOPSOP or DC lt 300 Y Q2 03 04 Current limited to LA R3 10k SIk 47k 47k All resistor are 1 4W unless otherwise noted R2 and R5 7 are high voltage resistors with the minimal breakdown voltage of 350V and 150V respectivelly Figure 1 Figure 1 shows a design with three P MOS FETs connected in series Neglecting the volt age drop across R1 the input voltage is ap proximately the same as the potential at Q2 s source Then the gate potential of Q2 equals the input voltage minus 6 2V across Zener D1 and plus any voltage drop across resistor R3 Resistors R5 R6 and R7 as voltage dividers ensure that the V s of each P MOSFET is ap proximately equal about 1 3 of the voltage difference between the input and output R5 is purposely chosen to have a slightly higher resistance than R6 and H as the gate potential of Q2 is about 5V less than the input voltage This correction equalises V voltages even more than if resistors R5 R6 and R7 were equal R4 ensures that at power on off Q2 is turned off At power on D1 provides 6 2V between the source and gate of Q2 V therefore Q2 is conductive Q3 and Q4 are conductive as well as the current through R5 R7 charges their gate to source capacitances The capacitor bank charging current is sensed with R1 and regulated with the negative feedback con trol consisting of R1 Q1 R3 and Q2 When the voltage between the emitter and b
7. and a Murata WiFi module There is also a ZigBee network copro cessor implying that the device may offer expansion options in peas oO www edn europe com the future n WIRELESS SENSORS PRECISE WIRELESS TEMPERATURE SENSOR POWERS ITSELF By Kris Lokere Linear Technology Corp he Internet of Things refers to a growing trend to connect not only people and com puters but all sorts of things to the Internet In applications such as industri al plants or large infrastructure projects connecting more sensors or actuators in more places can increase efficiency improve safety and enable entirely new business models Rather than the challenge and expense of running cables all around a factory it is now possible to install reliable indus trial strength wireless sensors that can operate for years on a small battery or even harvest energy from sources that are already available such as light vibra tion or temperature gradients This case study shows a real world design that combines a high resolution temperature sensor a power manage ment circuit that uses solar energy when available and battery backup when needed and a low power radio module that automatically forms a reliable mesh network to wirelessly connect all sensors to a central ac cess point SOLAR BATTERY PANEL WIRELESS NETWORK a battery or solar panel gt Design overview 20 EDN Europe JANUARY 2015 Figure 1 shows
8. bias voltage on MLCCs by Fons Janssen Maxim Integrated Precise wireless temperature sensor powers itself By Kris Lokere Linear Technology ONLINE THIS MONTH GaN The dawn of a new era By Janine Love EDN Embedded security rises and falls with crypto key management by Stephen Evanczuk EDN Death to half power handsets by Jeremy Hendy Nujira EDN s columns 3 EDN comment Glimpses of the future leave room for surprises 14 Analog Tips A 15 W precision difference amplifier with thermal shutdown by Chau Tran Analog Devices 19 Teardown A tale of two thermostats Nest teardown by Richard Quinnell EDN 31 Review Tektronix RSA306 spectrum analyser by Kenneth Wyatt 26 Product Roundup Power switch with current sensing low power FRAM HMI modules with touch cute cases for Raspberry Pi 21 Design Ideas 22 Three op amp state variable filter perfects the notch 24 Series connected MOSFETs increase voltage amp power handling 5 Pulse www edn europe com COMMENT s it is the start of a new year a number of Jose bodies have felt moved to share their thoughts on the most significant areas of technological challenge and opportunity that present themselves to us One such is National Instruments which has published its Trend Watch for 2015 In a series of short articles N looks at several specific topics from the prospect of 5G communications to the growth of the maker phenomenon Not unr
9. carrying the Touch Board microcontroller board that integrates an Atmel Capacitive touch enabled mi crocontroller chip MP3 play er SD Card slot Li Po battery charger and 12 electrodes The electrodes can be connected directly to conductors such as Electric Paint pads to trigger sounds via the MP3 player or other functions such as wireless communica tion or motor control added using an Arduino MSA gt expansion shield onrad Business Supplies has FLIR System Inc s thermal imaging product the FLIR ONE it offers the com pany s expertise in thermog raphy and thermal imaging cameras that enhance per ception and awareness in a pocket sized format With a slim case which attaches to an iPhone 5 or 5s FLIR ONE turns a smartphone into a thermal infrared camera giving the ability to see and measure minute temperature variations on the phone s screen Fitted with two cam eras including a long wave infrared Lepton sensor the FLIR ONE uses MSX Tech nology to provide thermal imaging capability and sharpness by blending the thermal and visible spectrum This technology allows the FLIR ONE to detect tempera ture differences as small as 0 1 C across a range of 0 C to 100 C With a dedicated battery providing four hours of continuous use the FLIR ONE does not place any additional power demands on the iPhone and it can be charged via a micro USB ada gt port e True Zero ohm jumper
10. devices and other larger devices Freescale Semi conductor has extended its wire less charging with what it claims as the first 15 W Qi compli ant wireless charging solution This chipset comprises two 15W ICs the WPR1516 receiver chip and accompanying MWCT1012 transmit ter chip which come with firmware librar ies The solution also includes an applica tion programming interface that can be used to modify or adjust library functionality allowing for the ad dition of custom application code and a highly tailored and differenti ated end product Iincludod in vehicle consoles Embedded in restaurani tables There is a production ready ref erence design and evaluation boards To support the WPR1516 receiver IC Freescale provides two evaluation board options for different output power topologies WPR1500 LDO and WPR1500 Located throughout homes HOTE Tai Incorporated in hotel rooms BUCK The MWCT1012 trans mit controller IC is supported with the WCT 15W1COILTX nas oO www edn europe com reference design Analog Circuit Design Volume Three Published by Elsevier Analog Cir cuit Design Volume Three Design Note Collection edited by ana ANALOG Circuit Design Volume 3 Design Note Collection Edited by Bob Dobkin and John Hamburger UNGAR logue circuit design leader Linear Technology s Bob Dobkin is the next book in the Analog Circuit
11. for each buck regulator and any unused power stages may be added to one of the high power channels for Complete article here QUAD 4x2A BUCK 1 of 8 Possible Configurations 2 7V to 5 5V Vcc 2 25V to 5 54 z VINA 2 25V to 5 5V Ving SWA Vour1 0 8V to VINA B Voura 0 8V to VINE F lour1 2A MAX lour3 2A MAX 2 25V to 5 5V a PA e 2 25 to 5 5V Vino VINH Voura 0 8V to VING H nl lout4 2A MAX Vout2 0 8V to Vinc D lout 2A MAX synchronous buck converters each powered from independent 2 20V to 5 5V inputs and each configurable to share up to four of eight available 1A power stages With eight unique output current configurations the LTC3371 pro vides flexibility and ease of reuse improved overall efficiency 8 EDN Europe JANUARY 2015 between the two terminals from 2 terminal constant current linear regulator improves LED current tolerance iodes Inc s AL5809 a two terminal PowerDI 123 pack aged device provides an im proved accuracy cost effective solution for constant current linear driving of LEDs With 1 2W maxi mum power dissipation 20 ppm C temperature stabil ity and high power supply rejection ratio the AL5809 delivers LED currents with a i 5 tolerance over a wide FS i A temperature range greatly simplifying the solutions for its target applications of LED signage LED strip ii K A lighting and
12. incorporates multiple optimisations to reduce energy consumption to less than 10 of that required by standard FRAM solutions With the MB85RDP16LX Fu jitsu is targeting industrial automation applications involving energy har A vesting for rotary encoders motor control and WINIE sensors The ultra low power device can enable self powering solutions such as the Wiegand wire based platform being offered by iC Haus MB85RDP16LX replaces separate read write operations with a single com mand from the MCU resulting MAR gt in energy savings of up to 94 High voltage inrush overcurrent input protection nalog Devices has posted details of the ADM1270 a current limiting controller that provides inrush current limiting and overcurrent protec tion for modular or battery powered systems The ADM1270 is designed to control the inrush current when powering on a system via an external P channel field effect transistor FET it manages the currents that charge bypass capacitors when circuit boards are inserted into a live backplane These transient currents can cause permanent damage to connector pins as well as dips on the backplane supply To protect a system from a reverse polarity input supply there is a provision made to control an additional external P channel FET use it in industrial modules and in battery vombiere oO article here powered portable instrumentation www edn europe com 2 channel high brightnes
13. low current ret Le rofit lamps The AL5809 is y ma 3 a small footprint low BOM ve ml Peet rem ture C cost LED driver that is sim ple to use and provides improved accuracy and all round higher performance than competitive alternatives or discrete circuit de signs The AL5809 Is specified for the 40 C to 125 C temperature range with an operating voltage 2 5V to 60V and is offered in vari ous fixed output current versions from 15 to 150 mA this removes the need for external current set ting resistors As well as meeting sensssssesdesssssnsssslasssssssssssssessslessssssasa 110 125 simple linear regulator e g no inductor or external resistor the AL5809 provides additional perfor mance features over temperature protection OTP and the ability to drive both low and high side LED chains Complete article here Arduino shields for RGB lighting and motor control from Infineon Infineon Technologies has added two shields for Arduino designs both are compatible to Arduino Arduino connectors lt 000000000 00000000 rea SNe i 8N0 5U LL PA P2 11 mm MMS Cafineon i i msc o m RGB LED shield Ed mote vr fea DE BUS with XMC1202 bh i i sc mm Ha sg Isolated DMX512 control interface optional DC input voltage Power on LED a uu NOIOSO Arduino connectors Uno R3 and can be combined with the XMC1100 Boot Kit which is equipped with a 32 bit microcon tro
14. the block diagram of the design The temperature sensor is based on a LDO out Figure 1 A wireless temperature sensor is formed by connecting a wireless radio module to an ADC reference and thermistor The circuit is powered by an energy harvester that can take power from thermistor biased by a low noise LT6654 volt age reference The 24 bit delta sigma ADC Download PDF of Article LTC2484 reads the thermistor voltage and re ports the result via SPI interface The LTP5901 is the radio module that contains not only the radio but also the networking firmware needed to automatically form an IP based mesh net work In addition the LTP5901 has a built in mi croprocessor which reads the LTC2484 ADC SPI port and manages the power sequencing for the signal chain compo nents The LTC3330 is a low power dual switch mode power supply that derives power from the solar panel when enough light is available and reverts to using the battery when needed to maintain output voltage regulation The LTC3330 also includes an LDO which is used to duty cycle power to the temperature sensor 3 0V DUTY CYCLED This article continues with a detailed description of the signal chain includ ing the analogue digital conversion employed the power demand power provision and power management and proceeds to the wireless networking part of the design The author concludes by returning to the key issue of power to look at the overall powe
15. 015 smartsystemsintegration com BE PART OF IT Knowledge exchange Trends and innovations Register now at mm narisystemsintegration com e9 S Networking Main conference topics e Smart energy systems e Smart Medtech systems e Smart production System integration and packaging Co organizer Fraunhofer Fraunhofer 1010 o OPO ntact bal of the activities of 449 711 61946 292 mM e S a g O ss La smart mesago com Messe Frankfurt Group TEAR A tale of two thermostats Nest teardown ome automation is the application where many consumers are getting their first introduction to the Internet of Things lo T so it seemed appropriate to explore how vendors are approaching device design in this market selected two devices to explore One was the Nest thermostat which generated consider able buzz in the market when it came out a few years ago The other was a more recent intro duction the Honeywell smart WiFi thermostat To see how the two compare when digging further inside began at the outer layer The Honeywell provides a full colour touch screen for controlling its operation One attri bute of this feature is that you can select the background colour to complement the colour scheme of your house The Nest thermostat has a look resembling that of conventional Permanent Hold press for options 19 EDN Europe JANUARY 2015 RICHARD QUINNELL EDN electromechanical thermostats w
16. 1 The conclusion of that article is that you should always check the capacitor s datasheet to see how the capacitance varies with the bias voltage But what if the datasheet does not include this information How can you determine how much capacitance is lost under the conditions in your application Theory for characterising capacitance vs bias voltage A circuit to measure the DC bias characteris tic is shown in Figure 1 This circuit is built around op amp U1 MAX4130 The op amp acts as a comparator with feedback resistors R2 and R3 adding hys 17 EDN Europe JANUARY 2015 co Q 01 4 100nF Ka B OUTPUT M C1 DUT ie ao Vy Vals T Figure 1 Circuit to characterise capacitance versus bias voltage teresis D1 sets a threshold above GND so that no negative supply voltage is needed C1 and R1 form a feedback network to the negative input which makes the circuit operate as an RC oscillator Capacitor C1 the device under test DUT serves as the C in this RC oscillator potentiometer R1 is the R The voltage waveforms of the op amp output pin Vy and the junction between R and C Vx are shown in Figure 2 When the output of the op amp is at 5V capacitor C1 is charged by R1 until it reaches the upper threshold This forces the output to OV Now the capacitor is dis charged until Vx reaches the lower threshold thus forcing the output back to 5V This process repeats resulting in a stable oscil
17. Design series The Design Note Collection is a comprehensive volume of applied circuit design solutions providing 10 EDN Europe JANUARY 2015 refined and practical design tech niques The book includes an ex tensive power management sec tion covering switching regulator design linear regulator design mi croprocessor power design bat tery management powering LED lighting automotive and industrial power design Other sections span a range of analogue design topics including data conversion data acquisition communica tions interface design operational amplifier design techniques filter design wireless RF communica tions and network design This book is 1136 pages in length and is available as an e book or a hardcover print version in Janu ary 2015 This book extends the series initiated by the successful publication of Analog Circuit De sign A Tutorial Guide to Applica tions and Solutions and Analog Circuit Design Volume 2 Immer sion in the Black Art of Analog Design Complete article here Obscured part numbers protect IP without the grind of grinding Companies frequently require markings on components to be re moved to make it hard for rivals to easily find out what parts are used on the PCB Contract manufacturer Es catec has developed a technique using an existing production machine that simpli fies the task and elimi f nates stress to com ponents
18. Designed to replace 0603 0805 and 1206 Zero ohm resistor chip sets without changing board designs or layouts e For high current applications Low Impedence Low profile Manufactured from Copper with Silver plate Supplied on tape and reel Compatible with vacuum pick amp place assembly systems Other chip set sizes available upon request Request Catalog M60 2 IT S WHAT S ON THE INSIDE THAT COUNTS EYSTONE European Headquarters www keyelco com 33 1 46 36 82 49 33 1 46 36 81 57 Om Sa Linux systems debugged in the field by embedded execution logging FR oversee debugging tools provider Undo Software has introduced Live Recorder a version of its toolset that assists in debugging Linux systems as they are running in the field or at an end customer s site The product is a two part offering The run time code is instrumented with library elements Live Recorder which when acti vated yield log files that can be transferred back to the development team who can apply the UndoDB reversible debugger Live Recorder al lows Linux programs to make a detailed recording of them selves while they are running The resulting Undo Recording enables developers to debug an exact copy of the original program s execution allow ing them to track down bugs without needing to reproduce them in house write test cas es or make time consuming 7 EDN Europe JANUARY 2015 visits to customer sit
19. Imec builds an all organic microprocessor COVER Organic transistor based MPU runs at 2 kHz ROM coded by ink jet esearchers at imec have produced an 8 bit microprocessor that runs at 2 1 KHz That is not a typing error for GHz 2 1 kHz is a breakthrough speed in this instance because the transistors that make up the processor s logic are entirely fabricated in low tempera ture organic materials Possible areas of ap plication include high volume printing of RFID tags Belgium s Holst Centre imec and their part ner Evonik have fabricated a general purpose 8 bit microprocessor using complementary thin film transistors TFTs processed at temperatures up to 250 C compatible with plastic foil substrates The microprocessor consists of two separate chips a processor core chip and a general purpose instruction generator P2ROM For the processor core chip a complementary hybrid organic oxide technology was used p n ratio 3 1 The gen eral purpose instruction generator or P2 PROM is a one time programmable ROM memory configured by means of inkjet printing using a conductive silver ink Complete article here o 2 EDN Europe JANUARY 2015 12 15 17 20 ARTICLES Design tips for an efficient non inverting buck boost converter by Haifeng Fan Texas Instruments Designing JESD204B converter systems for low BER Part 2 by Jeffrey Ugalde amp lan Beavers Analog Devices How to measure capacity versus
20. JANUARY 2015 ADE ENERGY METERING IG current sensor The ADE7932 features two 24 bit ADCs and the ADE7933 and ADE7923 feature three 24 bit ADCs One channel is dedi cated to measuring the voltage across the shunt when a shunt is ms used for current sens ing This channel pro vides a signal to noise ratio SNR of 67 dB over a 3 3 kHz signal bandwidth Up to two additional channels are dedicated to mea suring voltages which are usually sensed using resistor dividers The unused voltage channels on the neutral ADE7923 can be used for auxiliary voltage measurements These channels provide an SNR of 75 dB over a 3 3 KHz signal band width One voltage channel can be used to measure the temperature of the die via an internal sensor 978 Complete article here o SSL TLS secure socket code for embedded devices Segger s emSSL is a ground up implementation of secure sockets that are the backbone of secure communications on the Internet today Written to run on single chip embedded devices emSSL integrates seamlessly with embOS IP or alternatively any IP stack that supports plain sockets or any bidirectional communications channel emSSL supports TLS version 1 1 1 and 1 2 out of the box and provides modern cipher suites that offer robust authentication confidential ity message integrity and forward secrecy Whilst being compact it is also efficient in terms of RAM ROM and processor
21. T 2 By lan Beavers Jeffrey Ugalde Analog Devices We the adoption of the new high speed serial digital interface link known as JESD204B between converters and FPGAs the error rate within the digital transmission line cannot be ignored as a potential contributor to the overall BER Part 2 of this article continues the discussion JESD204B lane traces how long is too long Figure 6 shows other eye diagrams with the JESD204B receiver eye mask The plots depict the effects of conductor loss of the same 12 5 Gbps PRBS signal in 370HR PCB material for different channel lengths There is a direct correlation between insertion loss caused by different channel lengths and the amount of data eye closure relative to the mask for the same PCB material In this example the short est channel length of 1 in 2 5 cm has the least measured insertion loss This produces the best eye opening while the longest channel length of 12 in 30 cm produces the worst eye Opening In the two examples above the combined effects of timing jitter and amplitude noise as a function of insertion loss can be seen As inser tion loss increases so does the relative timing jitter and amplitude noise This reduces the 15 EDN Europe JANUARY 2015 HR370 12in JESD_Rx_Mmk HR370_8in JESD_Rx Mask 0 O 80 100 120 140 100 timo psec Figure 6 72 5 Gbps Eye diagrams of 370HR material using varying channel lengths eye opening available for data sampl
22. The RSA306 is powered solely through the USB 3 0 port The frequency range is 9 kHz to 6 2 GHz and can measure from 20 to 160 dBm at minimum resolution bandwidth of 100 Hz The unit can capture fast transient pulses with its 40 MHz real time IF bandwidth 31 EDN Europe JANUARY 2015 j b E a ii a I y F mW 4 r F r a F La il 7 F There are also external 10 MHz reference and trigger sync SMA inputs so you can sync to line frequencies for example The measure ment input is an N connector with protective user manual drivers and SignalVu PC software One reason for the low cost is that much of the functionality lies in the SignalVu PC RF analysis software The software includes 17 stan dard spectrum and signal analysis mea surements with several optional appli cation specific options available 757 each These options include mapping modulation analysis standards sup port such as APCO P25 and WLAN pulse measurements and frequency settling The real time DPX mode can i detect transient or intermittent signals as short as 100 usec which would aid in interference hunting The software can also capture streaming and audio a demodulation for long term surveillance 8 monitoring Because the personality of the instrument lies within the software upgrades and adding optional measure ment capabilities are easy In the complete article click right the author looks at PC host requ
23. alysis 28 EDN Europe JANUARY 2015 product NFC FRAM MCU transponder for industrial medical and wearable designs posos as the first flexible high frequency 13 56 MHz sensor tran sponder family Tl s highly integrated ultra low power RF430FRL15xH system on chip SoC family combines an ISO 15693 compliant Near Field Communication NFC interface with a programmable microcon troller ed A non volatile FRAM an analogue to digital converter ADC 7 SS and SPI or FC interface The dual interface nessornL1S f0 p 2 RF430FRL15xH NFC sensor transponder is i 3 optimised for use in fully passive battery E __ less or semi active modes in consumer gp fag Wearables industrial medi fae or transponder Cal and asset tracking ap 2 plications AM mm FTDI Chip s HMI modules focus on capacitive touch TDI Chip has added development modules to accompany its Em bedded Video Engine EVE modules that employ an object oriented approach to creating human machine interfaces HMIs The additional EVE platforms are targeted at the creation of intelligent display systems using Capacitive touch and are based on the FT801 EVE chip released in 2014 Both of the new modules touchscreens are able support from 1 to 5 independent touch points The VM801B is a 106 7 x 68 6 mm develop ment module with a choice of a 5 in or 4 3 in display plus an integrated ex ex projected capacitive touchscreen a
24. ase of Q1 reaches V that is when the charg ing current is about 1A Q1 starts to conduct As V 6 2 R3 x IC Q1 any increase in Isa decreases V This decreases the out put current which in turn decreases the voltage across R1 completing the negative feedback loop AV 200V C1 100 pF 16 1 s i AV 1 C 14 At Figure 2 shows voltage across the 40 000 uF capaci tor bank as a func tion of time as the 0 5 10 15 20 25 30 35 40 time s Figure 2 www edn europe com designideas Three op amp state variable filter perfects the notch capacitor bank is charged from OV to 300V for two different cases with and without C1 Without C1 the capacitor bank is only partially charged during each rectified half cycle that is when the input voltage is higher than the output voltage plus the voltage drop across all three MOSFETs of about 15V Hence the slope of the curve is not constant Adding C1 lets the charging circuit work with a more constant input voltage Calculations for C1 C1 discharges at the rate of dV dt I C 10V msec This is almost an order of magnitude slower than the sinusoidal change of the input voltage from 330V to OV that lasts 4 17 msec for 120 Hz half cycles Therefore from the mo ment the input voltage reaches its maximum the capacitor bank is charged only from the C1 capacitor until the input voltage exceeds the C1 voltage on the next r
25. e is only 30 larger The Osram Ostar Stage is equipped with four high current chips based on the latest thin film and UX 3 chip tech nologies With an area of 2mm each the chips are twice as large as the previous ones but at 5 7 x 6 4 x 1 3 mm the package size is only slightly gt larger Thin film chips in red 625 nm and UX 3 chips in green 530 nm blue deep blue 453 nm and white are used Up to 4 5A can be ap plied to each chip which allows more light to be produced from a Alina o www edn europe com small surface he spectrum analyser has always been a vital tool for the EMC engineer Until the last few years these instruments have been rather large and heavy desktop instruments weigh ing up to 30 kg or more With the break throughs in components used for wireless technology the size and weight of these instruments has decreased dramatically A few other manufacturers have pio neered the concept of PC controlled spectrum analysers and Tektronix has recently entered the fray with its RSA306 which has dramatically raised the bar in terms of performance and measurement capability The RSA306 is a well built rubber covered unit that is about the size that will slip into the jacket pocket of your suit 30 x 190 x 127 mm It would also fit easily into a briefcase along with a 15 inch PC laptop It is designed to meet MIL STD 28800 Class 2 environmental shock and vibration for use in harsh envi ronments
26. efficiency This article presents operational principles current stress and power loss analysis of these buck boost converters and presents design criteria for an efficient non inverting buck boost converter Inverting buck boost converter Figure 1 shows the schematic of a basic in 12 EDN Europe JANUARY 2015 verting buck boost converter along with the typical voltage and current waveforms in con tinuous conduction mode CCM In addition to input and output capacitors the power stage consists of a power MOSFET a diode and an inductor When the MOSFET Q1 is ON the voltage across the inductor L1 is Vp and the inductor current ramps up at a rate that is proportional to Vp This results in accumulating energy in the inductor While Q1 is ON the out put capacitor supplies the entire load current When the Q1 is OFF the diode D1 is forward biased and the inductor current ramps down at a rate proportional to V While Q1 is OFF energy is transferred from the inductor to the output load and capacitor The voltage conversion ratio of an inverting buck boost in CCM can be expressed as M Your n P 1 Vin l 0 n where D is the duty cycle of Q1 and is always in a range of 0 to 1 Equation 1 indicates that the magnitude of output voltage could be either higher when D gt 0 5 or lower when D lt 0 5 Vin Vout OOo i HIT Vout r pei I C a n _ In Four al I i Figure 1 nverti
27. elated to its instrumentation and test business N makes a specific comment on the test environment for coming generations of smart devices heading this article When Exposed to loT Big Iron ATE Will Rust In that piece the company argues that Traditional automated test equipment ATE was optimized to test technology that harnessed the power of Moore s law mostly digital increasing transistor count decreasing footprint and it does this very well But over the past few decades a subtle shift to integrate more analog technology into ICs has resulted in a test challenge that is much more than Moore Innovation for the loT has tasked test engineers to verify mixed signal systems that include both digital signals and analog signals from sensors RF antennas and more all at consumer volumes and for the lowest price possible For the testing challenges oftomorrow traditional ATE falls short Test engineers need smart ATE for the smart devices of the loT 3 EDN Europe JANUARY 2015 GLIMPSES OF THE FUTURE LEAVE ROOM FOR SURPRISES What NI is leading up to is the contention that just as the consumer products we all use have become adaptable app driven and software upgradeable so too will the test environments that check them out This reflects of course NI s ongoing product developments in software defined instrument functions It may also re inforce because it s a mode of thinking that is becoming e
28. es Undo Software s debugger al lows the code execution to be reproduced and rewound run in exact replica from a chosen point to reveal the sequences that led to a bug or failure Software failures in production the company notes can be notoriously difficult to fix The developer does not need to have an exact replica of the end cus tomer s hardware code flow will be faithfully recovered on a machine with same generic architecture as the target By capturing software failures Live Recorder provides devel opers with all the information they need to quickly respond to bugs that are found either in the field or internally within their own organisations Such as during software testing Complete article here GPGPU amp OpenCL boosts medical imaging throughput sing an AMD Embed ded Radeon HD 7850 GPU to accelerate medical imaging Analogic s BK Ultra sound bk3000 system gains a three fold increase in data contained within each im age together with a reduc tion in the time needed to pro cess each scan PEZ In this design in AMD s Embedded Radeon HD 7850 GPU is used to enhance perfor mance for the BK Ultrasound powered by Analogic bk3000 ultrasound system Analogic used the to gain access to the AMD graphics processing unit GPU for general purpose GP computing re ferred to as GP GPU delivering performance and offering system and develop
29. ew hints of anything that might spring on us from left field and create a major upset In fact in some of these areas technological progress is painfully slow If for example we are ever to have a world powered largely by ambient energy solar wind etc we must conquer the energy storage problem Today s batteries are far better than they were but in the context of the energy storage capability we would need to back up really large scale photovoltaics they are orders of magnitude away Other technologies exist but grid scale hold over appears a long way away However no surprises does not mean an absence of good insights and you can download the paper from IHS following a registration process to read for yourself What are the emerging or rapidly progressing areas of technology you expect to most impact you and your job In five years ten years or even one or two years www edn europe com QUAD 4x2A BUCK 1 of 8 Possible Contigurations 2 7V to 5 5V 2 25Y to 5 5V Vex Yoo Suc seo sun LTC3371 m ros pe FLL Moot 70 85 Ambient Temperature C Arduino connectors ADE7978 y ENERGY METERING c Circuit Design Volume 3 L PA i ha Design Note Collectior tn a ap 7 i i IN PHASE uA ADE79321 DIGITAL INTERFACE Arduino connectors Conductive paint ink reinvented for the maker generation Accessory makes IPhone a thermal imaging camera for the
30. ing Ideally the best location to sample the data is at the middle of the data mask However JESD204B receivers need some margin in the time axis and the voltage axis to correctly capture each bit Therefore as the eye opening is closed the probability of capturing and resolving an incor rect bit goes up This will affect the bit error rate of the link The effect of data rate to timing jitter and amplitude noise for a constant channel length is also important for maintaining a low bit er ror rate As data rate decreases the data eye opening will increase since the high frequency components at a slower data rate exhibit less insertion loss from the channel Higher data rates will correspondingly decrease the avail able data eye opening Figure 7 compares the eye opening seen at the receiver scaled to its corresponding UI unit interval The eye for a 6 25 Gbps data rate has less relative timing jitter and amplitude noise than the 12 5 Gbps data rate These examples show how the conductor loss and dielectric loss affects the eye opening and therefore affects the potential bit error rate of the JES D204B link Material quality and design techniques such as loosely coupled differential traces help im prove insertion loss This helps improve the eye opening and therefore improves the bit error rate of the link Best layout practices to minimise BER Depending on the application and its sensitivity to cost and area there are
31. ion shows that notch rejection is better on V than on V It may exceed 80 dB with high speed op amps at U2 amp US and is limited by the op amp specs Input impedance is not constant with frequency However neither rejection depth nor gain depend on source resistance which appears in series with R14 and slightly decreases gain and Q it is the same for Figure 1 An optional buffer U4 with gain equal to 1 R R may isolate the filter from any external disturbance and maintain gain at 1 The overall gain may of course be adjusted with R or R 23 EDN Europe JANUARY 2015 13 The output noise is extremely low across the whole spectrum even lower at W For example for U1 U2 amp U3 with e 5 nV JHz total noise at V2 4 5 nV JHz O w and 6 4 nV JHz in the rest of the spectrum Figure 4 Noise vs frequency Be wary of possible saturation of U1 to U3 at centre frequency w because their gains are high if Q is high as with any state variable filter The gains of U1 U3 at w are U R R Y R C R C U2 R R US 2 R R 2 1 R R Saturation characteristics may be improved by increasing the ratio C C and or decreasing R R at the expense of higher noise A simulation file can be downloaded Saved as a text file delete any www edn europe com designideas Three op amp state variable filter perfects the notch Series connected MOSFETs increase voltage amp power handling
32. irements reviews the capabilities of the instrument then gets down to making some real world measure ments Complete article here LT laa AA A La Ua NE AA FEA x A rubber cap With all this Tektronix has been able to keep the cost down to just 2 810 for the basic unit Included in this price are a safe ty installation manual USB 3 0 cable and USB flash drive containing the documentation files CONTACTS PUBLISHER Andr Rousselot 32 27400053 andre rousselot eetimes be EDITOR IN CHIEF Graham Prophet 44 7733 457432 edn editor eetimes be Patrick Mannion Brand Director EDN Worldwide european business press CIRCULATION amp FINANCE Luc Desimpel luc desimpel eetimes be ADVERTISING PRODUCTION amp REPRINTS Lydia Gijsegom lydia gijsegom eetimes be ART MANAGER Jean Paul Speliers ACCOUNTING Ricardo Pinto Ferreira 32 EDN Europe JANUARY 2015 SALES CONTACTS Europe Monika Ailinger Switzerland 41 41 850 4424 m ailinger marcomedia ch Daniel Cardon France Spain Portugal 33 688 27 06 35 cardon d gmail com Nadia Liefsoens Belgium 32 11 224 397 n liefsoens fivemedia be Andrea Rancati Italy 39 02 284 6716 info silvera it Nick Walker UK Ireland Israel The Netherlands 44 0 1442 864191 nickjwalker btinternet com Colm Barry amp Jeff Draycott Scandinavia 46 40 41 41 78 jeff draycott womp int com colm barry telia com Victoria amp Norbe
33. ising slope of the 120 Hz period As C1 is discharged with the constant current of 1A the discharge time interval td is expressed as Van Ve 0 For this time interval the input voltage changes from 330V to OV and up to VC1 25 EDN Europe JANUARY 2015 Solving these two equations for VC1 shows that C1 discharges down to about 265V As the voltage drop across three MOSFETs is about 15V it follows that above 250V the voltage across the capacitor bank doesn t increase lin early This explains the variation from the linear dashed line in Figure 2 This circuit is part of a complex device our custom built defibrillator for research stud ies Ref 1 It has proven to work reliably for hundreds of cycles and hundreds of hours with numerous rapid discharges of the capaci tor bank over the last two years The circuit is tested up to an input voltage of 280 VRMS and works reliably with a heatsink temperature of up to 70 C This Design Idea is not limited to the input voltage and current specified herein The maximum input voltage and charging cur rent can be raised with the addition of more P MOSFETs in series The downside is the voltage drop across each P MOSFET of about 5V Larger C1 capacitances than 100 uF would linearise the charging curve at even higher volt ages or of course a DC input could be used Addendum The authors added this expansion on how why Q3 and Q4 are turned on consider the initial case at power
34. ith a simple colour display that indicates current and set point temperature colour coded to show if it is heating or cooling It senses the user s pres ence lighting up when approached but darken ing when not needed Unlike the touchscreen of the Honeywell the Nest has users rotate the outer ring to identify the action they wish to take then press the unit to confirm the selection Audible clicks accom pany these actions to provide haptic feedback The Honeywell wall plate is a simple two layer PCB with connectors for the wires com ing from the HVAC unit The Nest wall plate has active components including an STMicro STM32L151 microcontroller and an 8 channel analog Mux The bubble level in the centre is there to aid in proper installation of the back plate to the wall The Hon eywell unit s single PCB in cludes DC DC converters voltage regula tors rectifiers an 8 channel 12 bit ADC 128 MB of SDRAM 32M of Flash and a Broadcom WiFi module shield removed An Atmel 926 ARM processor is the main processing unit enclosed by the metal shield just visible underneath the flat ribbon cable to the display sese of x f ohi ri Se U cb CAT ad te qe er fl A se i vi e han lt 5 Spat n na a amp gt 7 pi i x gt 5 The main board of the Nest with metal shield removed shows a TI Sitara CPU power manage ment and USB chip Flash 32Mx16 SDRAM
35. lation SPEER E E O UPPER THRESHOLD Vyp l E N l o I TIME Figure 2 Oscillation voltages V and V The oscillation period depends on the values of R C and the upper and lower thresholds Vp and V fav Vio nn T atin BRC Fro G r go www edn europe com SERIAL INTERFACING Since SV V and V are constant then T and T are proportional to RC This is often referred to as the RC time constant The threshold of the comparator is a function of Vi R2 R3 and the forward voltage of D1 V_ joe s R3 n R2 Dtode no 4 R3 R24 4R3 VruRESHOLD Where Vp is the threshold for Y 5V and VLO is the threshold for Y OV With the given values these thresholds yield to approximately 0 55V for V o and 1 00V for Vip LO The circuit around Q1 and 02 converts the cycle time into a proportion al voltage which is used to indicate the effective capacitance with differ ent applied voltages The continuation of this article enlarges on how the circuit works and produces results confirming the validity of the approach click below for pdf download Download PDF a of Article pr Find MLCCs on EETsearch 18 EDN Europe JANUARY 2015 ca as de o ceo mg CLICOCTA INC sma rts Yo LCS E u Im International Conference and Exhibition on Integration Issues of Miniaturized Systems MEMS NEMS ICs and Electronic Components Copenhagen Denmark 11 12 March 2
36. layout practices to consider for JESD204B high speed serial trans mission lines in order to minimise channel loss and mitigate the bit error rate High speed SERDES channel traces over 12 inches 80 cm in length operating at high bit rates of 12 5 Gbps are typically best routed on higher grade PCB material as cost permits www edn europe com 12in 126Gh ps HRI70_12in_6Gbps MASE bha HR370 50 100 150 fara 250 300 350 D wW l 60 ima piar hm psat Figure 7 6 25 Gbps left and 12 5 Gbps right eye diagrams using 370HR material with the JESD204B receiver Mask Better quality PCB material will reap the benefit of lower channel loss Channel traces under 12 inches of length operating at high bit rate should be acceptable in lower grade PCB material where emphasis and equalisation can be used to improve bit error rate of the JESD link It is commonly believed that 10042 dif ferential signals require differential traces Differential signals can be perfectly well routed on two 50Q single ended traces This is Known as a loosely coupled dif ferential pair Loosely coupled differential pairs are typically a differential pair where as Download PDF of Article 16 EDN Europe JANUARY 2015 0 i 120 dd 160 SERIAL INTERFACING the edge to edge spacing be tween signal pairs is at least three times that of the trace width e Tightly coupled differential pairs are differential pair
37. ller from the XMC1000family All XMC 1000 products use the ARM Cortex MO processor The Infineon RGB LED Lighting Shield for Ardu ino hosts the XMC1202 microcon troller with its Brightness Colour Control Unit BCCU for LED light ing control The high current DC Motor Control Shield for Arduino contains the Infineon NovalithlC 9 EDN Europe JANUARY 2015 Debug interface BIN8982TA an integrated half bridge driver for motor control The RGB LED Lighting Shield is an intelligent evaluation board for Arduino It allows the adoption of different LED light engines to ensure fast prototyping and inex pensive evaluation The Lighting Shield has three independent output chan nels for flicker free control of multicolour LEDs The DC Motor Control Shield with BTN8982TA for Arduino enables fast and cost effective prototyping of DC motor control designs with easy testing of half bridge and full bridge mo tor control applications The Motor Control Shield is capable of driv ing two uni directional DC motors or one bi directional DC motor The Shield implements two Nova lithIC BTN8982TA fully integrated high current half bridge drivers for PAR o motor drives to XMC1202 XMC1202 LED string connector pa DCDC LED J driver stage 15 Watt Qi compliant wireless charging Enabling faster charging than conventional USB and other wired technologies and supporting rapid recharging for tablets hand held medical
38. load emSSL s highly flexible and straightforward con figuration targets small devices by linking only what s necessary and at the same time avoids a sea of preprocessor defines that drown other source code products emSSL cements our intention to strengthen and augment Segger middleware with modern security features demanded by our indus trial customers says Rolf Segger owner and CTO of Segger Complete article here o www edn europe com POWER MANAGEMENT DESIGN TIPS FOR AN EFFICIENT NON INVERTING BUCK BOOST CONVERTER By Haifeng Fan Texas Instruments his article presents operational principles current stress and power loss analysis of several common buck boost converters and presents design criteria for an efficient non inverting buck boost converter Buck boost step down and step up con verters are widely used in industrial personal computers IPCs point of sale POS systems and automotive start stop systems In these applications the input voltage could be either higher or lower than the desired output volt age A basic inverting buck boost converter has a negative output voltage with respect to ground The single end primary inductor con verter SEPIC Zeta converter and two switch buck boost converters have positive or non inverting outputs However compared with a basic inverting buck boost converter all three non inverting topologies have additional power components and reduced
39. maker generation ass RS Components is ex panding its offering with products from Bare Conductive Electric Paint and the company s Arduino based Touch Board The products are aimed at the complete range of potential cus tomers from hobbyists to professional engineers and including the maker sector Electric Paint is a carbon based paint or ink that comes either in a direct dispense tube or pen or in pots for brushing or screening The product is electrically conduc tive in both liquid and dried states non toxic solvent free and water soluble It can be used as a liquid wire as a cold soldering medium or even as a conductive ad hesive for prototyping repairing PCBs and painting circuits and sensors on any surface It can be used to make ad hoc connections on any dielectric surface for example wiring up com ponents in education projects by say following a circuit drawn on paper 5 EDN Europe JANUARY 2015 The medium can be employed as a resistive or capacitive touch sensor it can be overpainted or placed behind a plastic panel to make it permanent it air dries but does not cure and remains water soluble Quoted resistivity is 55 2 square at 50 microns thickness clearly achieved resistance depends on applied thickness and the company says that 32 Q sq is typical for a layer applied by brush The product screen prints well Bare Conductive adds Also from Bare Conductive RS will be
40. mbedded in the industry the thought process that bids us ask of all the systems we use What if this worked more like a smartphone Is the traditional operation use model still the best for this or that product and so on NI also contemplates 5G whatever form it eventually takes and how that will inspire thinking beyond faster data and greater capacity the lloT or Industrial loT how the connected device and data analytics era will specifically affect the industrial landscape and the impact of the maker movement on innovation You can download NI s thoughts on the subject from the link above More futurology a list of 10 things this time comes from industry analysts IHS who canvassed opinions on which technologies are most likely to transform the world during the next five years Here is the list they came up with 3D printing Cloud computing big data loT Internet of Everything Artificial intelligence Biometrics Flexible displays Sensors Advanced user interfaces Graphene Energy storage and advanced battery technologies Does anything surprise you about that list Perhaps have been reading too much of this sort of thing but here s what surprises me there are no surprises It s exactly the list that probably resides in the desk drawer of every venture capitalist or at least of those that have not abandoned hard technology for life sciences and synthetic biology There are f
41. ment cost reduction through cross platform portability As a result of using AMD GPU technology Analogic achieved a 3x improve ment in the amount of information in each ultra sound image and reduced time from capture to presentation Traditional FPGAs and DSPs AMD asserts create a fixed inflexible implementa tion that requires custom software targeted at spe cific hardware Going toa software based solution using OpenCL helps to further lower the develop ment cost and provides improved long term value since the software can be used across product lines and through generation shifts A 4 Complete o article here Configurable buck DG DGs 8A from 2 to 4 independent outputs 1C3371 is a highly integrated general purpose power man agement solution for systems re quiring multiple low voltage power supplies The device features four across many different applica tions The device is suitable for a wide variety of multichannel indus trial automotive communications and distributed power systems The device s buck power stages can be connected in parallel by simply combin ing their respective VIN and SW pins and programming the desired configuration E sm on the C1 C3 pins LL Up to four adjacent n power stages can be i i combined on a single is AT UNU channel resulting in eight unique output configurations rang ing from a quad 2A buck to a dual 4A buck A single inductor may be used
42. nd E a fitted plastic bezel The VM801P adds a built in AT MEGA328P Flash E gt www edn europe com based microcontroller 50 mF wet tantalum capacitors challenge supercaps VX has developed a series of high CV wet tantalum capacitors that approach the ultra high volumetric capacitance densities of aque ous supercapacitors as well as overcoming their temperature and sol dering limitations Developed using a design process based on high CV tantalum powders the TWD DCUltraMax Series High CV Wet Tantalum Capacitors achieve extremely high DC capacitance values unlike aqueous supercapacitors they are rated for continuous high tem perature operation to at least 85 C and are compatible with both wave and reflow solder ing to a PCB Complete article here ARM mbed Bluetooth amp WiFi boards from CSR SR offers two connectivity products for the ARM mbed operating system that will enable developers to produce complete Internet of Things loT solutions CSR will offer two mbed ex pansion boards also known as shields one com bines Wi Fi and Bluetooth based on the CSR6030 and CSR8311 ICs The other offers Bluetooth Smart connectivity based on a CSR1010 chip These shields which will be released in early 2015 are designed to work with the ARM mbed OS that will also be available to developers in early 2015 The two systems will provide the fundamental connec Maire oO tivity required for all lol devices
43. ng buck boost converter than the input voltage However the output voltage always has an inverse polarity relative to the input Conventional non inverting buck boost con verters The inverting buck boost converter does not serve the needs of applications where a positive output voltage is required The SEPIC Zeta and two switch buck boost converter are three popular non inverting buck boost topolo gies The Zeta converter also called inverse SEPIC is similar to SEPIC but less attractive than SEPIC since it requires a high side driver that increases the circuit complexity A SEPIC converter and its ideal waveforms in CCM are shown in Figure 2 The voltage con version ratio of a SEPIC converter is www edn europe com Vin Vout Vin Vour F ae Wes lin lour F In boo lout ii x iS j A nm I M n III l E Figure 2 SEPIC converter ee TA M OUT D 2 Vin 1 D Equation 2 indicates a positive output voltage and the buck boost capability Like an inverting buck boost converter a SEPIC converter has a single MOSFET Q1 and a single diode D1 The MOSFET and diode in a SEPIC con verter have voltage and current requirements simi lar to their counterparts in an inverting buck boost s 13 EDN Europe JANUARY 2015 Download PDF of Article POWER MANAGEMENT converter As such the power losses of the MOSFET and diode are similar On the other hand
44. om ST updates Bluetooth network processor to BT4 1 TMicroelectronics has released the latest version of its BlueNRG Bluetooth SMART network processor which supports the latest Bluetooth version 4 1 enhancements and introduces 1 7V operation for longer lasting battery powered applications The BlueNRG MS network processor integrates a complete Bluetooth PHY and 2 4GHz radio ARM Cortex MO microcontroller running the Bluetooth 4 1 protocol stack and dedicated AES 128 security coprocessor The API power management and Flash are already integrated allowing direct connection to the application host controller using a simple SPI bus using clear software partitioning between network processor and host microcontroller ST s BlueNRG MS network processor can power devices such as a hub capable of collecting sensor data and subsequently acting as a peripheral to transfer the data to a smart phone It can also allow very large sensor networks with unlimited communication range controlled by a single smartphone 10 Watt class wireless power chipset oshiba Electronics Europe has a wireless power receiver IC TC 7 65WBG and a transmitter IC TB6865AFG Enhanced Version that together comprise a 10 W class wireless power solution for smartphones tablets and mobile accessories using the Qi Standard Low Power Specifi cations version 1 1 defined by the Wireless Power Consortium WPC The receiver IC TC7765WBG increases power by boosting the ou
45. on when the capacitor bank is discharged that is when the output is at OV For the input votage of 300V the gates of Q3 and Q4 will be approximately at potentials of 200V and 100V Q2 is initially conductive as it is biased with the Zener diode If we assume that there is no current flowing through Q2 that is if 03 and Q4 are off then potential at the drain of Q2 source of Q3 will be 300V and voltage between the source and gate of Q3 will be 100V therefore Q3 must turn on and Q4 subsequently Reference 1 Uzelac Holcomb M Reiserer RS Fenton FH Wikswo JP High Power Current Source with Real Time Arbitrary Waveform for In Vivo and In Vitro Studies of Defibrillation Computing in Cardiology 40 667 670 2013 About the Authors llija Uzelac is a Post Doc at Georgia Institute of Technology designing research instrumenta tion microcontrollers control systems power electronic sensors measurements Teaching Industrial Control Systems Electronics circuits Hhe holds BSEE MSEE and BSc MSc and PhD degrees in Physics www edn europe com val fem Fee A n EO n wees Oo i Microchip OSPICIIEP 128GM304 i CE es IS fee ee Mi Da RE y a p _1g sii GaN half bridge betters 87 28V to 1V DC DC at 14A he EPC2101 GaN power monolithic half bridge used in a complete point of load PoL buck converter yields system efficiency that ap proaches 87 at 14A and ove
46. orts These notch outputs are taken from the two inputs of U1 labelled V1 amp V2 They are the sum of the input and BP output for V1 and the sum of the HP amp LP outputs for V2 The complete equation is V Ve R R R 1 o R C R C R R 1 jwR C R A R R R R 0 R C R C 171 272 R R where Ry Ry Rao Rig The numerator always has an exact zero at w 1 J R C R C R R Vinad D 5KHa 0 7KHz D 9KHz 1 1KHz 1 3KHz 1 5KHz 1 9KHz Figure 3 Notch frequency phase response www edn europe com designideas Series connected MOSFETs increase voltage amp power handling Low frequency gain is always equal to high frequency gain which means that rejection is naturally infinite at the centre frequency and does not depend on component tolerances Amongst all notch filters only the Bainter filter and here also possesses this property but its parameters cannot easily be tuned separately Further equations Q 1 R R 7 R C R C V R R R V R R V R R Q is maximum and the equations greatly simplify if we choose R R Then 2 15 V Vin R R R 1 w R C R C 1 jw R C 2 R R 1 R Ria w R R C LF amp HF gain A R R 4R Notch frequency w 1 J R C R C 171 272 may be tuned with R amp R Q Q 1 R R 2 R R V R C R C may be tuned with R Practically simulat
47. r 82 at 30A when switching at 500 KHz and converting from 28V to 1V while reducing the board area occupied by transistors by 50 when compared to a discrete solution EPC2101 is a 60V enhancement mode monolithic AS GaN transistor half bridge By integrating two eGaN power FETs into a single device interconnect inductances and the interstitial Space needed on the PCB are eliminated resulting in a 50 reduction article here the transistors 10A power switch with accurate current sense ilego Technology s 2 0 x 3 0 mm CurrentPAK SLG6M6001V enables high accuracy current measurement in a configurable and program mable 10A 3 8 mQ Rosan load switch CurrentPAK is a family of con figurable mixed signal ICs or CMICs A high performance load switch that has efficient high accuracy current measurement CurrentPAK is claimed as the first load switch to have advanced programmable features Using non volatile memory NVM designers can control several aspects of the device including enable logic slew rate current limiting over temperature protection and integrated discharge rate CurrentPAK SLG 6M6001V comes in a 2 0x3 0mm ASA oO fully encapsulated plastic package 27 EDN Europe JANUARY 2015 in board area occupied by Complete o product Low power FRAM for energy harvesting apps ujitsu Semiconductor s MB85RDP16LX is an ultra low power FRAM device with an integrated binary counter function It
48. r usage of the circuit THERMISTOR BRIDGE a Find wireless temperature sensors on EETsearch www edn europe com e Three op amp state variable filter perfects the notch e Series connected MOSFETs increase voltage amp power handling designideas Serles connected MOSFETs increase voltage amp power handling Three op amp state variable filter perfects the notch By Alain Temps The usual schematic of a state variable filter with two inverting integrators is well Known Curiously the input signal is almost always connected to the minus input of U1 Figure 1 is an example with w 1kHz and Q Figure 1 Typical state variable filter The circuit is known for its versatility and ability to simultaneously provide low pass band pass and high pass outputs Gain centre frequency and Q may be adjusted separately A notch filter is usually obtained by adding a fourth op amp either to sum the LP amp HP outputs which are out of phase or to difference the input and BP outputs which are in phase The notch depth then depends on 22 EDN Europe JANUARY 2015 the matching of the resistances used for adding or subtracting the signals In this Design Idea the input signal is instead connected to the positive input of U1 the filter naturally generates two notch outputs without 150n C2 KA NOTCH R3 ik 14k V Figure 2 New state variable design with two notch outputs the need to combine any p
49. rs level such that the thermal protec tion circuitry is not activated under normal circumstances BY CHAU TRAN ANALOG DEVICES In addition to short circuit protec tion the ADA4870 is protected against excessive die tempera tures When detected the am plifier switches to an off state dropping the supply current to approximately 5 mA When the die temperature returns to an accept able level the amplifier automati cally resumes normal operation This thermal protection mode is very useful to prevent long term thermal stress of the circuit A device can heat up to a relatively high temperature if the fault con dition is temporary This greatly reduces the stress imposed by thermal cycling which in turn improves its reliability under sus tained fault conditions generate heat causing the die temperature to increase so a heat sink will be typically be required to improve the long term reliability and keep the die temperature at a Chau Tran chau tran analog com joined Analog Devices in designs 1984 and works in the Integrated Amplifier Products IAP Group in Wilmington MA In 1990 he graduated with an MSEE degree from Tufts University Chau holds more than 10 patents and has written more than 10 technical articles The ADA4870 draws about 30 mA but a power saving shutdown fea 14 EDN Europe JANUARY 2015 www edn europe com SERIAL INTERFACING DESIGNING JESD204B CONVERTER SYSTEMS FOR LOW BER PAR
50. rt Hufmann Germany Austria Eastern Europe 49 911 93 97 64 42 sales hufmann info EDN EUROPE is published 11 times in 2015 by European Business Press SA 7 Avenue Reine Astrid 1310 La Hulpe Belgium Tel 32 2 740 00 50 Fax 32 2 740 00 59 email info eetimes be VAT Registration BE 461 357 437 RPM Nivelles It is is free to qualified engineers and managers involved in engineering decisions see http www edn europe com subscribe Copyright 2014 by European Business Press SA All rights reserved P 304128 USA amp Canada Todd A Bria West 1 831 477 2075 tbria globalmediasales com Jim Lees PA NJ amp NY 1 610 626 0540 jim leesmedia com Steve Priessman East Midwest South Central amp Canada 1 630 420 8744 steve stevenpriessman com Lesley Harmoning East Midwest South Central amp Canada 1 218 686 6438 lesleyharmoning gmail com Asia Keita Sato Japan 81 3 6824 9386 Mishida mx itmedia co jp Grace Wu Asian Sources Publications Asia 886 2 2712 6877 wug globalsources com John Ng Asian Sources Publications Asia 86 755 8828 2656 jng globalsources com
51. s automotive LED driver o use in automotive display backlights automotive lighting ap plications and LCD backlights Maxim has posted detail of the MAX16838B which it says is the only available 2 string HB LED driver providing 10000 1 dimming ratio the part has high voltage boost and and a SEPIC controller The device is a dual channel LED driver that inte To grates both the DC DC switching boost regu ES lator and two 150 mA current sinks A current t ne mode switching DC DC controller provides the necessary voltage to both strings of HB LEDs The MAX16838B accepts a 4 75V to 40V input voltage range and directly withstands automotive load dump events Complete article here Most powerful embedded Linux C C debugger reen Hills Software has a new MULTI software development environ ment for embedded Linux developers you can develop projects for the Internet of things cheaper and faster the company asserts Green Hills presents its MULTI as enabling developers to seamlessly control and debug all aspects of an embedded Linux system including the Linux kernel kernel threads user mode threads and processes and interrupt service routines ISRs all from a single tool MULTI enables developers to quickly master development challenges including kernel pan Ics execution and data flows between user processes and the kernel early igen gt hardware bring up device driv ers and performance an
52. s where the edge to edge spacing is less than 3x that of the trace width Wider spacing on differential pairs has a lower conductor loss due to increased surface area for skin effect In the case where signal loss is important which is typically on long traces high data rates and with lower grade PCB material loosely coupled differential traces are es sential Interconnects vias and sharp 90 de gree corners in transmission lines typically affect the characteristic impedance of the channel and any deviation from the de signed characteristic impedance will result in unwanted reflections in the transmitted signal Avoid using vias as much as pos sible in high speed differential traces Read the complete article plus Part 1 in the pdf download click below Find JESD204B converter p systems on EETsearch EE Times AUTOMOTIVE www edn europe com ANALOGUE DESIGN HOW TO MEASURE CAPACITY VERSUS BIAS VOLTAGE ON MLCCS By Fons Janssen Maxim Integrated igh capacity multilayer ceramic capaci tors MLCC have a property often not well understood by electronic designers the ca pacitance of these devices varies with applied DC voltage This pnenomenon is present in all high dielectric constant or Class Il capacitors B X5R R X7R and F Y5V characteristic The amount of variation can differ consid erably among different MLCC types A good article on this topic was written by Mark For tunato Ref
53. tput voltage from 5V 1A to 7 12V 1A The transmitter IC TB6865AFG Enhanced Ver sion realises a 10 W class wireless power solution based on a revised peripheral circuit configuration and new software The TC7765WBG s built in protocol authentication logic circuit for power supply control elimi nates the need for set makers to develop software The TB6865AFG Enhanced Version also supports the software ore o necessary for the higher power supply operation 30 EDN Europe JANUARY 2015 Complete article here o product Raspberry Pi Arduino based project case paermor Electronics 1593HAMEGG enclosures are board specific designs that provide a ready made housing for the Arduino and Raspberry Pi bareboard computers Available in translucent blue translucent purple or translucent black they have been designed to provide an alternative to traditional base and lid designs where the bareboard is mounted inside an enclosure The new cases are config ured for the Raspberry Pi A A B and B and the Arduino Uno Due Ethernet Leonardo Mega ADK Mega 2560 and Yun Board specific ver sions for designs from other manufacturers active in this sec BA o tor are in development 4 colour LED module high lumen output istributor Rutronik has the Osram Ostar Stage LED from Osram Opto Semiconductors Compared with previous members of the product family it offers more than twice the lumen output whereas the compo nent surfac
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