hybridfree/eevblog-posts huggingface dataset:
Dell PSU dps-600fb adjusting 13.8V output - Page 1
Forum section: electronics / projects

author: AndreyS
author_rank: Regular Contributor
timestamp: December 15, 2015, 01:19:35 pm
content: I want to modify Dell PSU DPS-600FB so that I could use it to charge car battery. From that what I've read the voltage has to be 13.8V in order to charge normally it.I saw the 12V output voltage on some Dell PSU can be adjusted via grid pins.The voltage resistors are adjusted by manufacturer very precisely, I wouldn't want to change it, I want to use PSU in PowerVault 220s, and sometimes to charge the battery.What I did so far: I checked pins on PowerVault's main board to figure out how to run PSU. So bottom left pin was grounded on it. I attached image with known to me pins (marked).Unfortunately, there isn't much on the web regarding this PSU.The PSU is controlled by CMOS OTP-based 8-bit microcontroller packs Microchip PIC16C72A (main web page,datasheet).One guy told to add a 2.1 k ohm resistor to +S to - S get 13.6 volts. But where +S and -S are?

author: madires
author_rank: Super Contributor
timestamp: December 15, 2015, 01:54:52 pm
content: The voltage regulation is done by an analogue feedback via an opto coupler. Find the voltage divider at the output voltage and you'll know. The MCU does possibly some management and monitoring stuff, like monitoring voltages. Maybe it would also need a mod to be happy. Unless the 3.3V and 5V outputs aren't based on buck converters, those voltages might increase too by your 13.8V mod.

author: lukaq
author_rank: Regular Contributor
timestamp: December 19, 2015, 04:51:13 am
content: In most cases you have pot to adjust output voltage. Some supply's need external pot or resistor. But in many cases, you will hit OVP before you get that 13.8V or higher. I'm not sure if that is the case on all DSP's, but I would say on most of them.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 19, 2015, 05:13:11 am
content: What about build a boost converter? With a tapped push pull design, the MOSFETs won't even have to handle much current.
Delta PSU "Quarter Dome" startup pins? - Page 1
Forum section: electronics / projects

author: slurry
author_rank: Regular Contributor
timestamp: November 05, 2016, 09:50:18 am
content: Recently i was given this DELTA smpsu, it delivers -48V and 1600WI would like to get it up and running, to do that on most DELTA PSU's i have got just need a jumper between two or more pins to start up from it's standby mode, also a resistor to trim the output voltage.Like this Delta DPS-800 server supplyhttp://static.rcgroups.net/forums/attachments/3/1/3/5/4/3/a3961299-180-HP%20DPS-600PB%202.jpgOriginally my -48V psu came from a huge Cisco router so this is most likely specifically made for Cisco, although there is no stickers telling "Cisco" anywhere.inside, on the pcb it says "ascom energy systems" so it seems that ascom and Delta collaborates.Maybe someone already have figured out the pinout?
Delta servo 17 bit serial encoder signal protocol ? - Page 1
Forum section: electronics / projects

author: Kjelt
author_rank: Super Contributor
timestamp: April 25, 2020, 07:21:40 am
content: Hi all,I have bought a 2nd hand Delta ASD-B2-0221-B servo driver in the hope to interface it with an Omron servomotor with the same specs.However too late I found out that the Omron servo has the quadrature encoder output but the Delta driver has someting like a 17bit serial connection input T+ T-.So this is probably some sort of balanced serial signal containing the 17 bits position (or more with 0's) of the encoder, but I can find zero information about it.I read about absolute encoders with an SSI interface but they have seperate clock and data lines. So could this be some form of combined encoding, like spdif did back in the day ?Does someone have any info on this signal? Would be much appreciated.
Delta TDPS-150 Switching Power Supply - Page 1
Forum section: electronics / projects

author: Mike_2012
author_rank: Newbie
timestamp: June 05, 2023, 10:36:31 pm
content: Hello team,I am recently working on repairs for Delta TDPS-150 switching power supply.(I do not currently have its schematic available but working to reverse engineer it and hopefullywill soon post some information.)Input 100 - 240V ACOutput 12V 12.5A maxI have included some PCB photos for your reference.Anybody who is willing to share anything about this or ask questions is welcome******************Next - here's (1st Draft) rev-engineered schematic of the 'High voltage' side of the power supply.All repairs so far had burned parts only on that side - never on the Low, 12V side.So I have decided to skip the "12V" part of the schematic - at least until I get aboard where it appears damaged, otherwise this would not make sense to me to reverse-engineer.High and Low voltage sides are galvanically separated by 2 transformers (L8, L9 are primarywindings of the 1st (Main) power transformer; L1 and L2 are the primary windings of the 2nd transformer) and 3 opto couples (U1, U2 and U9).L3 transformer has both primary and secondary windings on high voltage side only.Lower part of the schematic was the most complex part (to reverse-engineer (:-)) and likelyhas a lot of errors - e.g.most of the junction transistors have mismatched Collector, Emitter and Base. Several componentsare not identified correctly - i.e. I have mistakenly drawn a transistor while it could be someother component - like voltage detector, etc. (This is because of the cryptic 2-3 letter/numberon the SMD chassis making it difficult to determine correctly - with 100% certainty.)(I have used Digi-Key's free "Scheme-it" to draw the schematic and unfortunately only when reachingtoo far into this drawing found there was no easy way to make any changes - once the components got connected ...)For approximately my initial ~10 repairs this is the list of most often failed components:IC3845 (usually always with R98 1kOhm SMD resistor melted)IC6562Q12 (MOSFET)Q801 (MOSFET)R84 (0.33 Ohm/ 1W)R907 82Ohm 1W through-holeS1 and S2 fuses (4 Amp)Notes:U8 (IC3845) and U5 (IC6562) pins are not represented correctly - as shown on the diagram; I have only followed the usual "bottom-left" starting pin#1 convention as for the most (digital) chippin-numbering.LM393 is correctly shown (except its PWR and GND (2 unnumbered pins) are not connected on the schematic); however I guess this is not critical for the analysis ?Some diodes could be Zener diodes (or vice-versa) because I have relied on the PCB component markingsbut can have errors.All 'American' type resistors represents '0-Ohm' (bridge/protection) resistors on the PCB board and can be ignored while 'reading' of the schematic function.
Demo: Autonomous Vehicle powered with TaraXL Stereo Camera & NVIDIA TX2 - Page 1
Forum section: electronics / projects

author: jm677zz
author_rank: Newbie
timestamp: December 05, 2018, 03:07:46 pm
content: Watch the demo of Autonomous Vehicle using TaraXL & NVIDIA TX2 for its Vision Processing, driving autonomously avoiding obstacles and navigating the area with its stereo vision.
Derivation of Phase Shift Oscillator Formula from first principles? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: June 28, 2021, 08:04:20 am
content: Hi!I am trying to write up, in Appendix F, Section 4 of my new T & M Theory and Repair Book, how the formula for the frequency of the Phase Shift Oscillator is derived from elementary principles using mesh analysis and Kirchoff's Current Law on the three branch phase–shift RC network!The write-up is posted here at:–https://electronicscoach.com/phase-shift-oscillator.htmlAssuming all Rs and C's are the same value, for the first node of the network, I can follow it as far as:–Va = Vo(1 + 1/jωRC) + V/R((2 + 1/jωRC)(1/jωRC)). . .which they say solves to:–Va = Vo(1 + 3/jωRC – 1/ω²R²C²). . .but I can't work out the intermediate steps between these two expressions, as I think there's a mistake been made or something's been missed out somewhere!Can somebody who's a bit more expert at complex algebra explain how the second expression comes from the first one please?Chris Williams

author: merlinb
author_rank: Contributor
timestamp: June 28, 2021, 09:30:51 am
content: In the last term you have added an extra 'R' that shouldn't be there, which may be what's confusing you.(2 + 1/jωRC)(1/jωRC) <-- remove that R!should be(2 + 1/jωRC)(1/jωC) = (2/jωC - 1/ω²C²R)You can figure the rest, right?

author: Chris56000
author_rank: Frequent Contributor
timestamp: June 28, 2021, 10:02:50 am
content: Hi!Member "Merlinb", you're quite correct, I did write down the term:–Vo/R(2 + (1/jωRC)(1/jωC)). . .in error, but I'm afraid it's still not making sense, I can get"2/jωRC". . .by direct addition of two (1/jωRC) terms in the whole expression for Va but I can't fathom out where the third one comes from!Chris Williams

author: merlinb
author_rank: Contributor
timestamp: June 28, 2021, 10:15:12 am
content: Va = Vo(1 + 1/jωRC) + (Vo/R)(2 + 1/jωRC)(1/jωC)Start by multiplying out the last two bracketed terms ('j²' turns into '-1' of course)Va = Vo(1 + 1/jωRC) + (Vo/R)(2/jωC + 1/[-ω²RC²])Multiply that lonesome 'R' into the brackets, and we'll move that distracting minus sign out of the denominator too:Va = Vo(1 + 1/jωRC) + Vo(2/jωCR- 1/ω²R²C²)Now factor out the common 'Vo':Va = Vo(1 + 1/jωRC + 2/jωCR - 1/ω²R²C²)The two middle fractions have a common denominator, so combine them:Va = Vo(1 + 3/jωRC - 1/ω²R²C²)

author: Chris56000
author_rank: Frequent Contributor
timestamp: June 28, 2021, 10:33:16 am
content: Hi!Member "Merlinb", thank you – I'd made a mistake expanding the second bracketed term, in omitting to multiply "2" by "1/jωC inside the bracket to give "2/jωC" – it's a great many years since I had to expand algebraic expressions on a regular basis!I can see how it all works out now!Chris Williams
Descreet Logic VFD Clock - Page 1
Forum section: electronics / projects

author: TheEPROM9
author_rank: Frequent Contributor
timestamp: June 28, 2013, 01:24:39 pm
content: For quite a few years now I have been working on a VFD descreet logic clock. The chalenges have been designing my own custom multiplexer (Best way to learn about multiplexers). Also the clock section of the circuit. I have now finished the multiplexer design and need to finish building it. Also still need to design the clock part of the circuit.Thought people on the Blog would be interested plus advice and pointers would be very helpful, espeshaly in the clock section.Also I have a nice retro setup.Link:http://www.eprom9.comeze.com/VFD%20clock.html
Descrete transformers pairs for 100 Mpbs Ethernet - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: October 17, 2024, 01:20:45 am
content: Hi,because of space constraints I am thinking of using two of these mini SMD transformers instead of a full Ethernet transformer:https://www.coilcraft.com/getmedia/a775ad5d-df75-4a65-939f-1b45403ec9fd/1812trx.pdfThe application is 100 Mpbs and those two transformers have two different inductance. Why two inductance values? What is the practical difference between the two inductance models?Most importantly, which one is the preferred one for 100 Base-T?Also, if my understanding is correct, specifically for 10/100 Base-T, I don't need to connect the centre taps, is that correct?Thank you

author: DaJMasta
author_rank: Super Contributor
timestamp: October 17, 2024, 05:56:55 am
content: If it's for space constraints, why not use a connector with the magnetics integrated?I'd post the digikey link to RJ45 jacks that are at least 100 base T with integrated magnetics, but it's enormous. I'm seeing 809 choices, and most of the connectors are only slightly bigger than an ethernet jack without them integrated.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 17, 2024, 08:14:28 am
content: There are plenty of very cheap single-channel ethernet magnetics on LCSC - I used these a while ago where I had a very tight height requirement.https://www.lcsc.com/products/Pulse-Transformers-LAN_543.htmlThe datasheet will usually tell you what speeds they are intended for. the Centre-tap is usually needed for the PHY. The PHY datasheet or appnotes should tell you what inductance it's designed for

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 17, 2024, 08:16:16 am
content: Quote from: DaJMasta on October 17, 2024, 05:56:55 amNot all ethernet interfaces have an RJ45 jack ( or not local to where the magnetics need to be)

author: ricko_uk
author_rank: Super Contributor
timestamp: October 17, 2024, 07:53:57 pm
content: Thank you both
Description of Pulse Train FM Detector on Github - Page 1
Forum section: electronics / projects

author: kvd
author_rank: Contributor
timestamp: April 13, 2021, 11:28:18 am
content: Hi,On Github I published a project with a detailed description of the workings of a Pulse Train FM Detector. This is accompanied by a mathematical model, implemented in a Jupyter notebook with which experiments can be done. In the pdf document also a possible improvement is mentioned, together with some preliminary experimental results.The project can be found athttps://github.com/kvdijken/Pulse-Train-FM-Detector.The main document (pdf) of this project is attached to this message.This FM detector is also used in an actual FM receiver designed and built by myself. There is a github project for the receiver, athttps://github.com/kvdijken/FM-Receiver.I have a demonstration video of this FM receiver on youtube:https://www.youtube.com/watch?v=TlIiLwKdwg0&t=1s.Greetings and have fun, Koen

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: April 13, 2021, 11:52:54 am
content: Hi Koen, nice writeup.Your urls have a dot appended at the end and thus are not working properly.(also, I see that you cross-posted this into the RF forum too)
Design a ATS - Page 1
Forum section: electronics / projects

author: NASK
author_rank: Contributor
timestamp: June 08, 2018, 08:22:35 am
content: I need to design Automatic Transfer Switch (ATS) using contactors. Our Grid supply is 3-Phase & MCCB rating is 100A , GEN is 5KW & 20A max. How can i choose a proper contactor for this design. Some one told me it is not possible make it through contactors because a spark can be happen when high ampere switching and contactor are not suitable for do it. and he told me to buy a automatic changeover insted of going to design. i need to clarify this thing.

author: Ravichandran
author_rank: Contributor
timestamp: June 08, 2018, 09:02:02 am
content: Actually, designing an ATS is a very dangerous task. Because you are going to mess with two different power sources. If you made a small mistake, your generator is done. But about the question you asked, it is possible to use a contactor with suitable ratings. You can even use a relay if the ratings are matched.

author: dmills
author_rank: Super Contributor
timestamp: June 08, 2018, 10:34:23 pm
content: UK practise is to use a pair of contractors fitted with a mechanical interlock kit as well as a normally closed auxiliary contact on each unit, the combination providing both a mechanical and electrical interlock to prevent both contactors being active at the same time.Given you only have 5kW on the auxiliary set, I would probably partition your loads onto two distribution boards, one for the majority of the load that you can afford to dump on grid failure and one for 4kW or so that needs to be switched over. This way you can protect the upstream supply from the grid @20A and only need 20A contactors to do the changeover.Note that there is a nasty trap if doing this on a TN-C-S supply in that a generator is quite likely outside the equipotential zone, so you may want to think about redoing the earthing scheme to be TT with RCD protection instead of TN-C-S.If ANY of the above is a mystery you really just want to just buy the transfer switch and have someone else do the install, three phase does tickle so when you cock up.Regards, Dan.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 09, 2018, 03:39:53 pm
content: Dual interlocked contactors are commonly used to reverse 3 phase motors.
Design a UCB C delivery  circuit - Page 1
Forum section: electronics / projects

author: newbadboy
author_rank: Regular Contributor
timestamp: October 06, 2025, 11:56:01 am
content: Basically i want to connect different USB powered stuff to a normal bench power supply and i need some circuit to negotiate the different protocol for maximum power delivery.I found 2 interesting ICs but they seem so simple compared to circuits from the more known manufacturers. Kind of to good to be true. Also the datasheet are not complete and there isn't much to find on the internet about these.I cannot either find them at the normal resellers. But they must be for real because JLCPCB have them in their component database.So my question are:1 Are they really working well with basically no external components and no need of MCU or whatsoever?2 Where can they be purchased?3 Is here full datasheet around somewhere4 Is there good options from other brands that are as simple as these?HUSB380Bhttps://www.hynetek.com/uploadfiles/site/219/news/6e530779-1a32-4897-8411-bb00c2f02d5b.pdfHUSB382https://www.hynetek.com/uploadfiles/site/219/news/5c125c25-9ef2-4d76-b911-74911221213f.pdf
Design Aid Robot Follower (electrical diagram and PCB) - Page 1
Forum section: electronics / projects

author: Bob-Sto
author_rank: Newbie
timestamp: May 01, 2024, 01:37:38 pm
content: Hello everyone,I plan to build a line-following robot from A to Z, but with fragile skills in electronics. I would like to receive your opinion on the electronic schematic of the robot.The robot has:3 sensors (VL53L0X)An OLED screenA compass (HMC5883L)5 sensors (QRE1113GR)2 encoder motorsThank you in advance for your help!

author: SteveThackery
author_rank: Super Contributor
timestamp: May 01, 2024, 03:37:29 pm
content: In the section 'Motorisations', aren't D2, D4, D6 and D8 upside down?Also, U2, U4, U5, U6 and U7 don't seem to do anything. I think the labelling might be wrong.

author: aliarifat794
author_rank: Regular Contributor
timestamp: May 03, 2024, 06:10:47 pm
content: This is very advanced I see. If it is your first robotics project, it's better to make something easy like this:https://www.theengineeringprojects.com/2016/08/line-following-robotic-waiter-using-arduino.htmlIf not, then go ahead with your design and check the motorisations part as SteveThackery suggested.
design and implementation of an inductively sensed keyboard - Page 1
Forum section: electronics / projects

author: listofopions
author_rank: Newbie
timestamp: April 30, 2018, 01:46:41 am
content: So to start this whirlwind off, let me begin by saying I'm a bit of a keyboard nut (I'm typing this on a model F bigfoot, with a soarer`s converter) so be warned!This is my first post on this forum, so thanks for the platform Dave!I've begun the design process for an inductively sensed keyboard, the mechanism is partially inspired by the ITW magnetic valve(https://patents.google.com/patent/US4263582A/en)which inspires the matrix, and the hp pulse transformer which inspires the sense mechanism(page 44,https://docs.google.com/open?id=0B4Wyz4bY7XjLLV9hUnB2WGFqck0)the hypothetical method of operation is as follows (I wish I had more work in EE, as I'm a mechatronics engineer,so please tell me if this is sensible, and what changes need to be made):the controller selects one of 8 columns to ground, and selects one of 16rows to power with the pwm; both via a 74hct4051 multiplexer. the pwmcycle is one pwm signal and one inverted (net ac current of 5v max per thevoltage dividers on the pwm pins), and is begun shortly after the row andcolumn are selected. if there are keys depressed in the selected columnthere should be an inductive short on the transformers and therefore ahigher voltage on the rows of the column not selected by the rowmultiplexer. this voltage is sensed by comparitors that are biased by aknown set-point that is established for the comparitors via a windoweddac, and resistors R1, R2, and R3.the attached kicad schematics should help (I hope) with the explanation.anyway, my main problem at the moment is the design of the sense transformers for the keypad (under the assumption that matrix sense mechanism is sound)I am assuming that I can use the design from the HP pulse transformer keypad, which is double spiral transformer (the other end of the coils is via-ed in the centerto the other side of the pcb) I've got the fast field solvers loaded and installed on my computer and I have some idea of how to use them (thank god fordocumentation!) but I would appreciate, and desperately need some guidance on the design of the sense transformers, like the entire design!and if that's not the main problem with this design let me know, any advice or input is much appreciated!

author: listofopions
author_rank: Newbie
timestamp: April 30, 2018, 02:10:36 am
content: Oh I should also mention that I need to have some help with layout! I am assuming that for the parts used I can just simply use the datasheets suggested layout.I am a little worried about the way I have the AGND, and GND coupled through a capacitor, as that would cause the grounds to a different potential, but because this isan inductive load that the multiplexers are driving, I think I would need to separate the driven inductors from the rest of the logic. I've also gone ahead and attached apdf of the kicad schematic.
Design bipolar current source - Page 1
Forum section: electronics / projects

author: alexscep
author_rank: Contributor
timestamp: February 24, 2015, 10:35:39 pm
content: Could someone help me or give me any suggestions concerning my following question.I want to design a bipolar current source based on the howland current source design. But i want to achieve a programmeable current source with a range of -200mA to +200mA. But i am not certain how to achieve these high currents using the howland design. And i should add, that everything would be controlled via a uController. Thus i'll be needing an DAC an digital potentiomter for this design i guess.Any help and suggestions would be greatly appreciated.Thanks in advance

author: SArepairman
author_rank: Frequent Contributor
timestamp: February 24, 2015, 11:35:52 pm
content: use a power op amp + modified howland current pump, what frequency do you need?you can either use1) voltage follower for feedback on regular howland current pump topology2) power op amp > current set resistor with a instrumentation amplifier across it (measuring voltage drop and using it as feedback), which turns it into a current sourcethen for digital control:use a DAC as a input for either of the two above topologies

author: moffy
author_rank: Super Contributor
timestamp: February 25, 2015, 02:10:33 am
content: You could just use 2 opamps and an NPN for the sinking current and a PNP for the sourcing current. Connect their collectors together and you have a transcoductance amp with intrinsically high output impedance.
design CC1101 module - Page 1
Forum section: electronics / projects

author: asadi.siyavash
author_rank: Contributor
timestamp: September 01, 2014, 07:54:26 pm
content: Hi,I want to design a module for CC1101 like RF1100SE , I can't use such a module because in the second phase I should design a complete board with this chip and microcontroller in one boad, but I don't have experience in RF designs. I have many experience in PCB design but I don't design any RF board. is it very difficult? where I should to start? is it possible to design it in 2 layer PCB?any help would be greatly appreciated .

author: Gribo
author_rank: Frequent Contributor
timestamp: September 02, 2014, 02:11:07 pm
content: The easiest step would be to copy TI's reference design (supplied in the EVM) for the required band. It is a 2 layer design. If you cannot fit that into your product, you can reduce its size by choosing smaller components (0402 vs 0603, 3.2x2.5mm crystal vs HC49 and so on).

author: asadi.siyavash
author_rank: Contributor
timestamp: September 02, 2014, 02:57:14 pm
content: Hi Gribo,I downloaded TI's design files before, it is 4 layer PCB.I attached its layout
Design challenge project under way: Linux-capable SBC without BGA, round 1 - Page 1
Forum section: electronics / projects

author: technix
author_rank: Super Contributor
timestamp: March 10, 2017, 08:40:47 am
content: I have decided to buy the parts and start the layout process. Specs:Board general:* 2-layer maximum. Double side loading acceptable.* Hopefully Arduino Mega form factor for unused I/O pins* 1x USB micro-B, 1x USB Type-A, 1x RJ45 10/100 Ethernet, 1x JTAGProcessor subsystem* CPU: AT91SAM9260B-QU ARM926EJ-S @200MHz in QFP-208* Modified CMSIS-DAP debug connector for JTAG (using the NC pin and one of the GND pins for NTRST and RTCK lines)Memory Subsystem* RAM: Winbond SDRAM (32MB, I forgot the actual part number)* Boot ROM: Adesto AT45DB321E (4MB DataFlash) for U-Boot, or AT45DB641E (8MB DataFlash) for U-Boot + Kernel* Onboard permanent storage: Samsung K9F4G08U0B (512MB SLC NAND) for kernel + root filesystem.Power Subsystem* Power source: USB, Li-Po* Li-Po charger: TP4056 1A linear charger.* Power converters: LM3671-3.3 SMPS for 3.3V digital rails, LM3671-1.8 SMPS for 1.8V rails, LP2980-3.3 LDO for ADC.* Platform controller: STM32F030F4 Cortex-M0 microcontroller.Connectivity Subsystem* Onboard USB Hub: Terminus FE1.1s, to combine the processor onboard USB and USB-Serial adapter into one USB microB connector.* USB-Serial adapter: WCH CH340B* Ethernet PHY: Realtek RTL8201* Network Configuration Memory: 25AA02E48 (so I can use guaranteed unique MAC address)* microSD card slot for extra storageSoftware Subsystem* Operating System: Linux, hopefully 4.10.1 Mainline Kernel* OS Distribution: maybe Debian?

author: uer166
author_rank: Super Contributor
timestamp: March 11, 2017, 01:59:12 am
content: Sounds similar to what I'm attempting right now, except much more full-featured.2-layer with all that connectivity would be quite a challenge I think, I had trouble routing out the memory buses in a nice way on a 4-layer board.Comment on the memory: are you sure you need the boot ROM? AFAIK it can boot directly from NAND.Unfortunately I just got derailed today when it came time to solder the huge QFP on, bending the delicate pins and whatnot when trying to use solder-wick technique. Does anyone have good recommendations for soldering such a package without stencil/paste? Mine boots to the bootloader and talks to SAM-BA, but the SDRAM fails to initialize, probably due to shorts and/or open connections.Please keep posting progress, I'm very interested!

author: technix
author_rank: Super Contributor
timestamp: March 11, 2017, 02:59:24 am
content: I know that this chip can boot straight from some NAND, but I am using an Intel SLC NAND that is not on its supported NAND boot device list. The U-Boot (and kernel) on the DataFlash gives me a chance to load a driver for that Flash chip.
Design checking - Page 1
Forum section: electronics / projects

author: Karamel
author_rank: Regular Contributor
timestamp: June 14, 2015, 05:32:28 pm
content: Hi mentors,This summer, I would like to make a pcb which has got arm microcontroller, rs485 port, nrf24L01 rf solution. I have prepared schematics which are about my project. Could you look at my schematics? if you catch any mistake, Could you warn to me?Best Regards,KaramelPower:Microcontroller:Peripherals:

author: lapm
author_rank: Frequent Contributor
timestamp: June 14, 2015, 06:12:45 pm
content: One thing comes to mind that you should add reset switch... Especially if this is some sort of development board..

author: Karamel
author_rank: Regular Contributor
timestamp: June 14, 2015, 06:23:42 pm
content: Quote from: lapm on June 14, 2015, 06:12:45 pmat the same time, i am thinking thatthank you for your suggestionCould you see any mistake in my schematics?Best regards,Karamel
Design choice single or multiple chips - Page 1
Forum section: electronics / projects

author: areuz
author_rank: Newbie
timestamp: April 07, 2017, 04:27:37 pm
content: Hey,I'm working on a decentralised set of devices that are going to communicate using a RF69 transceiver - a sort of home automation system, but not quite.At first, I wanted to make a comms. module, with the transceiver and an AtMEGA (328p or less powerfull). Now I realised that I might need something more powerful - an ARM of sorts (like a SAM4N or SAM4L from Atmel).So, I wanted to ask, what is better:1. Running all of the communication code (message relaying, parity checking, encrypting.. etc.)andthe main code (depending on the device's purpose) on the Atmel ARM.2. Or running the comms. code on an ARM, and having the AtMEGA just occasionally receive a message directed at it, for.. switching something like a relay, logging temperature from sensors, etc.I don't yet fully understand how I would run both comms. and main code on a single chip - and I dislike the idea of a interconnected mess of thousands of lines of code being rewritten every time I flash the chip. I know that parallelization exists, but it has it's disadvantages with the less powerful chips... and I would still have to have the code as a single giant program, wouldn't I?What I mostly care about is the power consumption and ease of debugging, because debugging wireless devices is a nightmare.
Design Comparator Latch ? - Page 1
Forum section: electronics / projects

author: Nhan95
author_rank: Contributor
timestamp: November 27, 2016, 03:08:51 pm
content: I am designing a latch-comparator using cmos circuit shown in the picture. When I simulate, the output (the blue line) is not completely high logic or low logic level as I desire(the 3rd picture) . What's this problem ? How to solve this ? thank you.
Design Errors and PCB Libraries - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: June 18, 2017, 12:06:31 pm
content: In duration I am a relative newbie to this stuff so I forgive myself my many mistakes and try and learn from them...I have been using DipTrace, which I really love using, but it has the issue that either many components don't have libraries or I just can't find them.In a recent project I needed a 16MHz SMD Crystal to drive a PIC24FJ128GC006 so I picked what I thought was a suitable crystalE3SB16.0000F09G11AE - Crystal, 16 MHz, SMD, 3.2mm x 2.5mm, 9 pF and created a user pattern.It was only after the prototype board arrived that I realised my mistake... the crystal is on the diagonal not the end pins... nightmare!I've been in denial for months and the project has sat dormant but eventually today I found time and bodged it. Cut the top trace, bodge wire to corner, moved cap to corner.Tell me about your design errors and bodges... make me feel better.

author: rdl
author_rank: Super Contributor
timestamp: June 18, 2017, 03:58:48 pm
content: I found there were many things I didn't like about the pre-made Diptrace libraries. Once I discovered how easy it was to make your own, I removed all the ones that it came with and started over.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: June 18, 2017, 04:25:18 pm
content: Quote from: rdl on June 18, 2017, 03:58:48 pmTo be fair to DipTrace... my error here was a custom component and custom pattern... I just wired it wrong.

author: AndyC_772
author_rank: Super Contributor
timestamp: June 18, 2017, 04:38:15 pm
content: It's completely normal, not to mention good practice, to design your own symbols, whatever CAD tool you're using. If nothing else, it forces you to read the data sheet specification for each and every single pin on the device, and that can only be a good thing when it comes to wiring up the device and getting it to work.I've been bitten a couple of times, though. Once I got the VCC and VDD pins of a chip round the wrong way, resulting in a brief but smoky experience.Another time, I drew a symbol using the measurements given in the device's data sheet, which turned out to have been rounded off when converting from imperial to metric units. The pin pitch on the PCB was slightly out, requiring a skilled hand to gently fan out all 100 or so pins of a QFP to make it fit the board.
Design factors for RGB matrix & display character storage - Page 1
Forum section: electronics / projects

author: SL4P
author_rank: Super Contributor
timestamp: March 02, 2014, 06:38:41 am
content: I've made several scanned LED matrices in the past, but now heading into an RGB array (24x8 x3) for production...My first question is whether the duty cycle per blended colour will be too short - if I use a single string of 595s to drive the columns - and separated R/G/B PNP high-side drivers for each row - effectively turning what would be an 8-row multiplex into 24 rows (8 x R+G+B). Alternate is to have separate 595s for each colour.I can ramp up the scan rate and forward current - but short of bench testing, I'm curious if anyone has tried this - or do I just bite the bullet and jump in with three strings of column drivers !?Second question, as I'm only using 7+1 colours (primary & secondary - no PWM), I was wondering what the usual strategy is for character storage for each character in the display buffer... ? I'm thinking 5-bytes per character cell {the font character) and a bitmask for R/G/B and blink (all that I need... ) any thoughts ?Thanks
Design Feedback - High Voltage Amplifier Output Stage - Page 1
Forum section: electronics / projects

author: Matt Coates
author_rank: Contributor
timestamp: March 08, 2024, 02:25:10 pm
content: Hi all,I'm currently designing a high voltage amplifier for use with a piezo actuator. Electrically this actuator is equivilent to a 10uF capacitor. My design is based on the ADHV4702-1 evaluation board.https://www.analog.com/media/en/technical-documentation/user-guides/eval-adhv4702-1cpz-ug-1444.pdfI've added a unity gain output stage to allow for a higher load current (0.1A). I've also added a shutdown feature such that whenSHUTDOWN_ENgoes to 5V the amplifier is disabled and the output load discharges. For my appplication it is important the the output actuator can discharge/close in around 1ms during a shutdown event.Any feedback on the topology/values would be much appreciated! My main concern is making sure that Vgs remains within 20V during shutdown - the 1M may be too large to allow the gate to discharge at the same rate as the output load, though the larger this value becomes the less the FET is contributing to the output current.For reference the FET Q2 is a linear FET with a SOA that can handle 1A at 200V Vds (and 7A for 1ms). It has a input capacitance of 4nF (at 1MHz). The 39R discharge resistors can withstand 70W for 1ms.Thanks!

author: mawyatt
author_rank: Super Contributor
timestamp: March 08, 2024, 04:31:13 pm
content: Check the stability of the loop when driving piezo loads, as you noted they are highly capacitive!!Also, note that your output is basically unipolar and can't sink much current.Best,

author: PartialDischarge
author_rank: Super Contributor
timestamp: March 08, 2024, 05:58:26 pm
content: I would add a back to back zener+ diode, or just a diode, to prevent excess negative voltages at Vgs.Also note that the minimum out voltage of that opamp would be 2V which could be enough to turn on the FET

author: profdc9
author_rank: Frequent Contributor
timestamp: March 08, 2024, 10:45:43 pm
content: I have a design for a discrete high voltage op-amphttps://github.com/profdc9/HighVoltageOpAmpIt uses 2N5401/2N5551 transistors and it can use different TO-220 output transistors if more current sourcing is needed (e.g. MJE15032/MJE15033).It is designed as the front end for an audio amplifier but it could be used for a piezo if a series resistor is used to limit the output current to the piezo capacitance (perhaps 10 ohms).
Design for a programmable AC load - Page 1
Forum section: electronics / projects

author: johofz
author_rank: Contributor
timestamp: April 29, 2021, 01:08:58 pm
content: Hello dear EEVblog Community,I'm currently designing a test bench for dynamo hubs.The dynamos are claw pole generators and produce about 500mA at 6V (~3W nominal power).The current bench uses a 1Mresistor for open clamp voltage with a switchable a 12resistor in parallel as a load. The switching happens via a relay. The current test bench takes about 2min for each run an opens and closes the relay a few times within that time.The new bench will be based around a different principal allowing for much faster test runs (<5s). I'm not sure if the relay solution is still the best choice for a much higher switching frequency. It will be used for production and will have a high duty cycle. I don't want to solder a new relay in there every half year and my colleges would probably prefer not to hear the relay clicking in such a high frequency all day. Especially since it's a quiet environment at the moment.So I came up with an idea:I rectify the ac output and then use a transistor to apply a variable load. This came to mind because LED-headlights have rectifiers with CC regulators in them. This way the load would be much closer to the real application. I could use the MCU to measure the current via a shunt resistor and control the load that way.Here is a first draft of the system and the two possibilities:system overview:I didn't go through the effort of connecting the new design to the mcu but you get the idea."old" relay version:"new" rectifier + transistor version:Here is a basic spice simulation of the rectified version:A major flaw of this concept is it's behavior for low frequency / voltage. The dynamos ac frequency is directly coupled to it's rpm * pole pairsthe 85 Hz frequency already corresponds to a velocity of 50km/h. At the lower end of the frequency range (5km/h -> 8-10 Hz) I get a pretty bad response of the system like shown here:I need to use quite a lot of caps to get the low frequency/voltage to stabilize. I need to increase the time for the measurement as well to get a good estimation of the actual voltage. At least one full cycle under load.This aside I think it could work very well. I'm not sure how the "true RMS" multimeters do the rms conversion. The correct way would be to sample the ac wave in high enough resolution and calculate the rms from that. The rectifier approach seems a bit dodgy, but I have no other way to apply a variable load to the system in a reasonable way.Does anyone have experience with ac-voltage and current measurement other than mains-voltage? The low frequency really kills any of the shelf solution I know of.Greetingsjohofz

author: WattsThat
author_rank: Frequent Contributor
timestamp: April 30, 2021, 12:22:49 am
content: No idea if it would be suitable for purpose but there was an ac load here in reply #1. Obviously needs some changes for the low frequency but the concept is interesting.https://www.eevblog.com/forum/testgear/adjustable-ac-load/
Design for the Nixie Clock casing with miniature nixie tubes - Page 1
Forum section: electronics / projects

author: dimasua
author_rank: Newbie
timestamp: April 18, 2021, 11:01:11 am
content: Hi everyone, I'm planning to assemble a nixie clock, similar like here for example:https://nixiedream.combut with different nixie tubes, IN-2. They are the smallest nixie tubes I could find. I have already the schematic and working on PCB, but a design for the casing is always a challenge for me. What is a better case for a nixie clock? Classical or modern, just pure wood or with brass elements, or steampunk? If you can give me some ideas or inspirations, that would be awesome! Here is a video for the nixie tubes I'm referring to:

author: t1d
author_rank: Super Contributor
timestamp: April 18, 2021, 01:50:07 pm
content: Throw concrete into your considerations. No joke, concrete. It can be easily shaped to any form. It's cheap. It's heat resistant. It has weight, to make your clock stable. You don't need a shop full of tools to use it. Look up how to make concrete counter tops on YouTube, for the instructions you will need.

author: strawberry
author_rank: Super Contributor
timestamp: April 18, 2021, 03:39:50 pm
content: Quote from: t1d on April 18, 2021, 01:50:07 pm25...50kg and you need one teaspoon of ithow about clay or glass? with help of some traditional workshop

author: wizard69
author_rank: Super Contributor
timestamp: April 19, 2021, 03:20:22 am
content: Quote from: strawberry on April 18, 2021, 03:39:50 pmYou can actually buy concrete type products in small buckets. Often these are grouts or concretes for setting posts, patching holes or other special applications. Very handy and I've used such concretes for a variety of projects.However I'm very partial to wood and brass for these sorts of retro electronics projects. That might sound steam punkish but a well designed project base does wonders for the finished item. In fact a good cabinet is the difference between something sitting proudly on a shelf for a life time vs hidden in a closet. That cabinet or base must get the same attention as the electronics no matter what is made of.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 19, 2021, 12:43:13 pm
content: Here's something that might change your plans.
Design help for "smart switching" battery charger for DIY speaker. BMS? - Page 1
Forum section: electronics / projects

author: Bassblaster505
author_rank: Contributor
timestamp: October 09, 2021, 04:58:28 am
content: Greetings, ive been working on and off on this big Bluetooth speaker that runs on a 12V 4.5Ah SLA battery (it was free and holds a perfect charge lol). The plan was to toss together and get rid of loads of parts i have laying around and put them to use. The unit runs off an older car head unit with Bluetooth that will power a pair of 4" woofers and Dayton Audio tweeters. Its RCA preout feeds a separate mono TPA3116D2 amplifier thats sole purpose in life is to feed a 2.5Ohm 8" subwoofer. Not gonna lie i basically ripped the design from the "Blast Box 200" that Parts Express sells. Ive attached a block diagram of how the unit would be wired up, pay close attention to the power delivery section, as the 12V SLA will charge through a center negitive external charger that disables power to the rest of the unit when chargingThat original design was over 2 years ago and today i would be interested in using a "smart" (i dont know the actual name) battery and charger setup. In a perfect world i would like to run a 4S2P 18650 pack and have ONE single DC jack that will power the unit, charge it and play from battery power on its own. I Look at big name Bluetooth speakers for inspiration, Such as my Harman Kardon Studio 5 but i dont know HOW those circuits work. Is it just a BMS? or is there more to it?Sorry if made myself sound like a complete newbie, I've been into audio and analog circuits all my life, but ive never been big on battery power or its charging setups

author: viperidae
author_rank: Frequent Contributor
timestamp: October 10, 2021, 12:26:00 am
content: You're probably going to want a low voltage cut off, SLA batteries have their life shortened every time you discharge them completely.The capacity is also dependant on discharge current. A 4.5ah battery is only 4.5ah when discharged at 225mA. If you discharge it at 4.5A, expect something more like 30 minutes.

author: Bassblaster505
author_rank: Contributor
timestamp: October 10, 2021, 07:12:48 pm
content: There is a low voltage cutoff in the block diagram, but im into the idea of ditching the SLA all together and running a lithium cell pack and that "smart charger" deal that im not sure if its just a BMS or what
Design Help required! Metal Oxide Varistor - in-circuit health Monitoring - Page 1
Forum section: electronics / projects

author: aju11
author_rank: Contributor
timestamp: February 20, 2022, 06:16:49 pm
content: We have some applications (single/Three AC and DC) which have several MOVs connected in common mode (i.e. Line to Earth).We wish to monitor the health these MOVs and report the status over a data link (like RS485/232).Intension here is to predict the MOV failure event and take action before actual MOV failure occurs.I came across iTMOV series from Little fuse. But is it the only way?Can we monitor standard MOVs and GDTs?

author: coppercone2
author_rank: Super Contributor
timestamp: February 20, 2022, 08:04:19 pm
content: its a leakage test circuit, they are put into whole home surge protection systems. MOV increases leakage as it gets worn. I don't know the circuit though. Basically a light that turns on when it gets outside of specs.
Design inputs for prototype AC motor driver - Page 1
Forum section: electronics / projects

author: ghoetic
author_rank: Contributor
timestamp: May 06, 2020, 07:02:03 pm
content: Hello EEV!I love motor control.I have tried designing my first real PCB for a prototype AC driver, i would like some input on the layout.This is my second take at an AC drive, first was successfull on veroboard -->https://www.youtube.com/watch?v=0gZrBgXn4NI.This design borrows from microchips AN1660.230VAC input, isolated user interface, slots between to220 legs, gate drive might be wide, but the best i can do?Linking some screenshots and attaching gerberhttps://imgur.com/a/26PSZTg
Design layout with a Teensy 4.1 - Page 1
Forum section: electronics / projects

author: metertech58761
author_rank: Frequent Contributor
timestamp: March 03, 2024, 02:08:20 pm
content: So I have this project that's been bouncing around in the back of my head for some time now...I finally decided to see if I can use a Teensy 4.1 module for the logic / interface side of things, but I need some guidance with selecting the pins to use on the Teensy 4.1 module.First, power: Does the Teensy generate its own 3.3V supply or do I need to have an external 3.3V source? I would have 5V coming in from a power supply board I set up.If I understand right, I just connect the 5V supply to pin 48 and then pull the 3.3V for three things (display, relay input pull-ups, power for the level shifter) from the Teensy?The functions I need to allocate:Four digital inputs (to sense relay closures)One digital output to drive an optoisolatorTwo I2C lines to drive an LCD8 pins for a 4x4 matrix keyboard (all 16 switches in that matrix would be used)One pin for a serial data input - this will need to be level-shifted from 5VOne pin for serial data output - this will need to be level-shifted to 5VOne pin to set send / receive mode - this will need to be level-shifted to 5VI will also need to generate two timing waveforms, both 50% duty cycle.One is to be a switchable 12.5kHz output, as it will be XOR'd with the serial data line (Manchester encoding)The other is to be a continuous 2439 Hz output to time the interrupt code.Can these be generated on-board or am I better off using a dedicated module to generate these?