hybridfree/eevblog-posts huggingface dataset:
DC-DC / PSU for up to 60V input, 5V output @ ~2-3 Amps - Page 1
Forum section: electronics / projects

author: WanaGo
author_rank: Regular Contributor
timestamp: January 16, 2020, 05:11:16 am
content: Hi,Just wondering if anyone has any ideas for a switchmode or suitable DC-DC, for dropping 24V or 48V batteries down to a 5V level, with about 2-3 Amp capacity.Its for a battery monitoring system.Just trying to find suitable parts, ideally SMD/SMT parts to mount onto a PCB.Not really wanting a module which has to sit off a PCB, prefer like a little Switching DC-DC or something.So far havent really managed to find much.Any switcher IC's I have found have sort of been up to 1A max, and can do about 36V input, nothing really over that.I have found some little modules, like a little PCB with multiple components, but they are $10+ each.I am not necessarily looking for a 1 part solution, an IC with inductor and passives etc is what I had in mind, its just trying to find a suitable part to start with I have no had much luck with as of yet.Anyone have any ideas?I have found these:https://www.digikey.com/products/en?dc=81646https://www.digikey.com/product-detail/en/murata-power-solutions-inc/OKI-78SR-5-1.5-W36HE-C/811-3289-ND/6817694I could use 2 of these at a push if I had to...But ideally wanting something like this, but with higher output amperage capacity.https://www.digikey.com/product-detail/en/linear-technology-analog-devices/LT1933ES6-TRPBF/LT1933ES6-TRPBFTR-ND/959504Any help would be appreciatedThanks

author: angust_uk
author_rank: Regular Contributor
timestamp: January 16, 2020, 11:50:03 am
content: I've used the LM5005 from TI in a past project where we needed a wide input range -https://www.digikey.co.uk/product-detail/en/texas-instruments/LM5005MHX-NOPB/LM5005MHX-NOPBCT-ND/3526995Worked well for me, and on brief inspection seems to meet the criteria

author: angust_uk
author_rank: Regular Contributor
timestamp: January 16, 2020, 04:59:26 pm
content: Quote from: blueskull on January 16, 2020, 03:21:48 pmThat's exactly what I used:

author: WanaGo
author_rank: Regular Contributor
timestamp: January 17, 2020, 12:47:39 am
content: Thank you everyone, this is great stuff.We had considered a transformer, but that is not ideally really, but it is something we thought we might have to go with...But this LM5005That looks great. I don't know why that never came up in searches I had done on Digikey.Many thanks, I am going to look into this now.2.5A could be plenty. 2A likely will be enough for what we can work with.Thanks very much
DC DC PSU input filtering - Page 1
Forum section: electronics / projects

author: andersendr
author_rank: Regular Contributor
timestamp: October 19, 2012, 03:50:17 am
content: Not sure of the best description for the subject as I do not have a lot of experience with power supply's. Not even sure if this would be called a PSU. I have 24VDC supplied from lead acid batteries with the need to apply filtering or isolation to better clamp over voltages. This will be regulated down later to power a MCU but this post is mainly on the over voltage protection. Also connected to these batteries are the DC PM motors which are connected through a controller that will allow for regenerative breaking. I am trying to determine a solution to reduce the high voltage transients during regen braking. My current thinking is to use TVS diodes but thought I should ask the community what they think. If you need more info let me know.

author: Kremmen
author_rank: Super Contributor
timestamp: October 19, 2012, 03:00:57 pm
content: The battery will absorb a not insignificant amount of braking current. If you supply the MCU from a psu circuit with high enough max input voltage, then it is quite possible that's all you need. You cannot easily use overvoltage clamping diodes or TVSes since you don't have a low impedance reference handy where to shunt the overvoltage. The battery won't do because that will always exhibit the voltage of your regeneration...Depending on the size of your motors you might need braking resistors to keep the voltage in check. But then you also need a way to activate the resistors which creates more complications... Easiest solution: design the MCU psu with high enough max input voltage that you won't hit it in normal operation. Possibly you will want to look into some kind of emergency crowbar if there is a real risk of significant surges.

author: andersendr
author_rank: Regular Contributor
timestamp: October 19, 2012, 10:37:30 pm
content: All right that makes sense. I never really thought about that I had no where to dump the over voltage when using a TVS. Good point about just using a voltage reg with a high enough input.Would it be acceptable to maybe use two regulators? Have the first one that will convert a range of 24V to spike down to 24V and then another one that will regulate that 24V max down to the MCU voltage.

author: Kremmen
author_rank: Super Contributor
timestamp: October 20, 2012, 01:47:33 pm
content: Sure you can use 2 regulators in series. Commonly that arrangement is used so that you have a rougher (switching) pre-regulator that drops the voltage nearer to the final voltage and then an accurate one (linear) to produce the final output. The is no physical law that says how you must do it but that way you minimize power losses and maximize accuracy and dynamics of the solution. Most commonly you see these in lab power supplies where transformer secondaries may additionally be switched as needed.
DC-DC recomendations for PMA5-83-2W+ sequencer - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: June 14, 2024, 05:03:00 pm
content: Hello,I need to build a sequencer for by the guidelines below..Given that i have +-12V voltage supply.questions:1.What DC-DC do you reccomend me to use to get the +5V needed for the amplifier?2.given that i control the system with microcontroller , what is the best wat to measure the current going threw the amplifier and control the Vg1 accordingly?Thanks.https://www.minicircuits.com/pdfs/PMA5-83-2W+.pdf

author: xvr
author_rank: Frequent Contributor
timestamp: June 14, 2024, 05:46:38 pm
content: QuoteYou don't need DC/DC - maximum load current for +5V is just 4.5mA, so any linear regulator will be fine. Use one with EN signal to turn on/off +5V voltage (VG2).Much more problem will be with VG1 (-2V). It should be adjusted in range -2V till -0.5V during startup. I think you need some DAC (it cound be real DAC or just PWM + RC filter) and invertor (on opamp) to perform this task.QuoteYou can use any current sense amplifier (from specialized IC to shunt resistor and instrumentation amplifier) and ADC

author: john23
author_rank: Frequent Contributor
timestamp: June 15, 2024, 08:14:35 am
content: Hello XVR, could you reccomend me such device a 5V regulator with Enable pin?"linear regulator will be fine. Use one with EN signal to turn on/off +5V voltage (VG2)"Thanks.

author: xvr
author_rank: Frequent Contributor
timestamp: June 15, 2024, 11:03:19 am
content: TAR5S50TE85LFQuote from: john23 on June 15, 2024, 08:14:35 am

author: xvr
author_rank: Frequent Contributor
timestamp: June 15, 2024, 12:42:37 pm
content: Opamp for negate Vg1 - TLV9301 (can be powered from +/- 12V rails)

author: xvr
author_rank: Frequent Contributor
timestamp: June 15, 2024, 01:08:25 pm
content: Current sense amplifier - INA21x, LT6119
DC-DC regulator for motor - Page 1
Forum section: electronics / projects

author: okw
author_rank: Frequent Contributor
timestamp: June 28, 2025, 11:49:06 am
content: I'm designing a DC-DC regulator (buck) for a motor. Powered from LiPo batteries (~32-34V), but should be able to handle around 36-40V in. 24V out and constant 7A (not sure about inrush current, but perhaps 3x).What regulator and MOSFETs do you recommend (LCSC budget parts preferred).What cooling would you recommend? Heat sink, or would smart layout be sufficient?

author: langwadt
author_rank: Super Contributor
timestamp: June 28, 2025, 12:36:05 pm
content: why dc-dc and not directly pwm the motor?

author: okw
author_rank: Frequent Contributor
timestamp: June 28, 2025, 01:05:27 pm
content: That's what my friend wanted

author: DavidAlfa
author_rank: Super Contributor
timestamp: June 28, 2025, 01:33:40 pm
content: What kind of motor? brushed or brushless?Anyway, Aliexpress is your friend:https://www.aliexpress.com/item/1005008151511430.html

author: Siwastaja
author_rank: Super Contributor
timestamp: June 28, 2025, 03:42:28 pm
content: You don't want to do that, because then you need to design the motor controlleranyway, and if you do that, then the DC/DC pre-stage is completely unnecessary and does nothing useful.Motor controllerisa buck converter with current limit and without output inductance and capacitance as the motor does equivalent of both (inductance and inertia/BEMF).

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 28, 2025, 09:11:33 pm
content: I agree with Siwastaja here. the original post smells like anhttps://en.wikipedia.org/wiki/XY_problem

author: Ian.M
author_rank: Super Contributor
timestamp: June 28, 2025, 09:26:02 pm
content: Yes, the only reason to use a pre-regulator would be to support a BLDC motor with built-in controller that's not rated for the max. battery voltage, and that cant be replaced by one that is!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 28, 2025, 11:42:05 pm
content: Quote from: Ian.M on June 28, 2025, 09:26:02 pmNo! Even if the motor is "rated" for only half the battery voltage, you just set the BLDC motor controller to regulate from 0% to 50% instead of all the way up to 100%. That's all. And even in this case, you can regulate to a higher peak percentage, maybe even all the way up to 100%, but you will be overdriving the motor, and will have to keep a keen eye on overheating. It's quite common for "industrial" servo motors to have a peak power rating that is 3 or 3x the normal maximum power. And these peaks can be used for quicker acceleration or for other times when short power bursts are needed. But in any case, there is no need at all to add a pre regulator to a BLDC motor, unless the difference is extremely big (such as running a 12V motor from a mains power supply.)And that is why I smelled the XY problem. OP may be chasing the wrong problem here, but there is not enough info to be sure.

author: Benta
author_rank: Super Contributor
timestamp: June 29, 2025, 12:18:42 am
content: I have a feeling you missed the "built-in controller" part of Ian.M's post..
DC-DC stage of grid-tied inverter, HF transformer - Page 1
Forum section: electronics / projects

author: Wrydog
author_rank: Contributor
timestamp: October 20, 2016, 07:24:52 pm
content: I'm working on a full-bridge DC-DC converter stage for a several kW grid-tied inverter. Since it's grid-tied, the inverter needs isolation. A 60Hz transformer on the output seems would much larger and heavier than using some sort of smps transformer on the DC-DC full bridge stage.What type of boosting mechanism is prevalent for full bridge converters working with grid-tied inverters? Is it a simple turn ratio? Trying to find one with a 1:7:7 has come up empty so we will end up rolling our own, at least for the first iteration. Also, trying to get more than 100A through the primary at HF seems troublesome.Is there a better way to get the boost with a full-bridge topology?

author: johansen
author_rank: Super Contributor
timestamp: November 03, 2016, 06:56:27 am
content: its hard to beat the efficiency of a multi kw toroidal transformer.that said, you will probably need to employ a semi resonant or resonant topology to meet your effiicency targets at low load. lots of small transformers is frequently the method used.but you can do it all with one transformer. take a look at the inside of a 3KW eltek rectifier for example. 3 kw through a ~35 mm square, maybe 50mm long transformer.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 03, 2016, 05:56:32 pm
content: What's input voltage? I guess something around 48V, based on your ratio and amps?You may find using multiple channels (usually interleaved phase shifts) and smaller individual transformers works better.The physics at work is, your circuit impedance (primary and secondary) can be closer to the characteristic impedance of the transformer. At low frequencies, transmission line effects reduce to good old fashioned leakage inductance and parasitic capacitance. Both of which are at a minima when your circuit impedance is nearest the part's characteristic impedance.5kW at 48V is ~100A and 0.5 ohms, which is a pretty big challenge. Splitting that four ways gets you 25A and 2 ohms each. Which still isn't all that great (it's difficult making a transformer with impedances under 10 ohms -- the result is, leakage dominates your losses), but that's still quite helpful. And, you have the knock-on bonus that, each individual transformer is smaller, so the electrical length of the windings can be smaller, saving you even more.And as Johansen mentioned -- leakage isn't necessarily a bad thing. It's an advantage, for a resonant converter!Tim
DC DC step up converter with Square Wave input - Page 1
Forum section: electronics / projects

author: AlgoryThm
author_rank: Newbie
timestamp: July 02, 2021, 03:55:53 pm
content: Hello! Well, I have a moped with a charging system that barely gives 13V at idle rpm and goes up to 13.2V at full rpm. The consequence of this is that the battery charges very slowly and I end up being stuck with a dead battery quite often, since the discharge rate is much higher than charging rate. Instead of replacing the whole rectifier, can I use a cheap DC-DC step up converter to provide the battery with constant 13.8V-14V from a 13V-13.2V input? If it was pure DC I wouldn't ask this question, but the output signal of the rectifier is something like a chopped AC, it looks more like square wave output.

author: Terry Bites
author_rank: Super Contributor
timestamp: July 02, 2021, 05:24:59 pm
content: Get the charging system fixed properly- you may find there's an adjustment in the regulator. Or just find a replacement. A boost converter is not the solution.

author: AlgoryThm
author_rank: Newbie
timestamp: July 02, 2021, 05:38:32 pm
content: Hmm this is sad since I have to work a lot more on the moped than I first thought. But just for the sake of argument, in general can I use pulsed wave input to a DC DC converter?
DC dummy load - Page 1
Forum section: electronics / projects

author: zagg
author_rank: Newbie
timestamp: April 09, 2011, 06:56:22 pm
content: Hello all !I'm looking for a "simple and low cost" DC dummy load (kit or mounted) for testing my homemade power supply.Anyone know where I can buy one ? (I leave in France).Dave, you use a dummy load on some videos, can you give us more information about it ? :-pThanks in advance !!!Davy

author: Zero999
author_rank: Super Contributor
timestamp: April 09, 2011, 07:23:22 pm
content: The simplist solution is just a resistor, the next step up is a rheostat (a high powered variable resistor). Beyond that, you could use a constant currnet load, connect different value resistors in parallel with MOSFETs or do something more exotic like using an analogue multiplier to make a MOSFET purely Ohmic.

author: deephaven
author_rank: Frequent Contributor
timestamp: April 09, 2011, 08:11:08 pm
content: http://www.eevblog.com/2010/08/01/eevblog-102-diy-constant-current-dummy-load-for-power-supply-and-battery-testing/

author: johnmx
author_rank: Frequent Contributor
timestamp: April 09, 2011, 08:35:48 pm
content: I have build one:https://www.eevblog.com/forum/index.php?topic=2487.0Also, check this page:http://www.edn.com/contents/images/6541379.pdf

author: zagg
author_rank: Newbie
timestamp: April 10, 2011, 04:35:10 am
content: Hello,Thanks to all for your quick reply.Have a nice day,Davy
DC Load Banana Jack Adapater - Now for the Rigol DC Load - Page 1
Forum section: electronics / projects

author: edesign
author_rank: Newbie
timestamp: January 28, 2023, 06:01:41 am
content: Hi all,Just wanted to post about a new project I've been working on.I designed a DC Load adapter for the BK Precision, Keithley and other loads and have been selling them for a while but have developed and released a new model to now support the Rigol DL3000 series DC Loads.Hopefully anybody who gets it finds it as useful as I have.Selling on my Ebay listing here:https://www.ebay.com/itm/155381250603
DC Load for Battery Testing - Page 1
Forum section: electronics / projects

author: testian
author_rank: Regular Contributor
timestamp: June 20, 2017, 07:04:04 pm
content: Hi,for testing lead acid batteries I am currently designing a DC load with charging function and data logging. The data will be logged to an USB-Stick through an external PCB. Voltage and Current will be logged while discharging (constant current) and charging.It would be nice if you could look at the schematic and give me feedback about it.Basic principle:The Supply for the Load is from an external 12V SupplySpec:1.5-20V0-5A

author: testian
author_rank: Regular Contributor
timestamp: June 21, 2017, 06:50:14 pm
content: New Version.Everything cleaned up and the decoupling capacitors have been added.The AD8671 might not be the best choice for the differential current measurement but I had it laying around.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 21, 2017, 08:23:42 pm
content: i think BC327 pnp should be replaced with npn transistor and D1 reversed.

author: testian
author_rank: Regular Contributor
timestamp: June 21, 2017, 08:36:11 pm
content: Thanks, you are right.

author: testian
author_rank: Regular Contributor
timestamp: July 06, 2017, 01:01:03 pm
content: Update: Added a charge current limiter, changed the 1wire Temp sensor to an PTCAfter I etched the PCB from the previous design I noticed that I goofed up on the Arduino footprint. It had the wrong numbers assigned to the pin. Therefore I changed a few things and try it again. Attached you find the current schematic and PCB design. The relays will be on a cheap 2-Channel 5V module.

author: qrper
author_rank: Contributor
timestamp: July 08, 2017, 11:59:31 pm
content: Here's my version.Shown loading battery at 24 A. It's not smart, but works great.Mike

author: testian
author_rank: Regular Contributor
timestamp: July 11, 2017, 05:36:54 pm
content: Looks very professional.Here is my first prototype:
DC Load Simulator For Initial Startup Current - Page 1
Forum section: electronics / projects

author: bostonman
author_rank: Super Contributor
timestamp: February 08, 2022, 04:30:18 am
content: I have a 180W DC load box to test things like power supplies that works pretty cool. In the past I've had a few issues that I noticed on a power supply I built. I think the capacitance on the load caused the linear regular to not recover quick enough and caused voltage spikes at turn on.Does a way exist to place a load on a power supply that will simulate a near short from uncharged capacitors on an external load that a power supply is powering?I was thinking of a MOSFET between the input voltage and ground that quickly opens. I'm guessing issues would be: how long to simulate a short because I imagine it changes based on what item is being powered and how many capacitors are on the load.

author: jbb
author_rank: Super Contributor
timestamp: February 08, 2022, 04:36:37 am
content: It’s crude, but how about adding some capacitors with on/off switches to your load box?

author: bostonman
author_rank: Super Contributor
timestamp: February 08, 2022, 04:52:56 am
content: Not a bad idea, but think manual switches would be difficult to switch quickly.

author: inse
author_rank: Super Contributor
timestamp: February 08, 2022, 05:19:19 am
content: Think about what exactly you want to test.Connecting an uncharged capacitor to a supply rail is always a short circuit.The voltage regulator will always have to recover from that spike.Simulating the inrush behaviour by shorting the supply with a switch of any type is a critical idea, think about what happens if you apply this test to a car battery ... the switched capacitor would provide a safety backstop.Usually power supplies are tested for step response on 0/100% load.I have added a modulation input to my DIY electronic load, the switching speed is limited by the circuit design to some ms.I use this for impedance check of batteries.I don't know whats the bandwidth of your load, you could check with a current probe and a hard driven MOSFET on a low impedance battery.

author: David Hess
author_rank: Super Contributor
timestamp: February 08, 2022, 05:04:33 pm
content: Quote from: inse on February 08, 2022, 05:19:19 amThe problem can be a little more subtle than just recovering.During startup or when recovering from a short, the voltage error amplifier can suffer from integrator windup which causes the output to overshoot. Various methods are used to solve this including adding soft start capability, improving the recovery characteristics of the voltage error amplifier, and increasing output capacitance.

author: bostonman
author_rank: Super Contributor
timestamp: February 09, 2022, 02:13:43 pm
content: I guess one simple solution is to just build a bank of capacitors as a load and see how the power supply responds.Most likely it wouldn't be idea though because ESR would be different across different loads.
DC Load with Log Response - Page 1
Forum section: electronics / projects

author: German_EE
author_rank: Super Contributor
timestamp: September 21, 2015, 01:19:55 pm
content: I have just built a new variable DC load and whilst the power hardware is working fine I am having a lot of trouble controlling the beast. As a test the base of the sink transistors are fed from the wiper of a 20K 10-turn potentiometer with the ends of the potentiometer connected to ground and supply. For the first eight turns there is no load (well, about 10mA but who's counting) then at the end of turn nine the load is sinking 520mA and in the final turn the load goes from 520mA to the full 20A which is the capability of my supply.The eventual aim is to control this load over USB but obviously I cannot do this whilst there is a log response to the control voltage. What am I doing wrong here and how do I correct the design to give a reasonably linear response to a control input? I suspect that the problem is something to do with the gain of the sink transistors but I am not sure how I can correct for this.

author: tggzzz
author_rank: Super Contributor
timestamp: September 21, 2015, 01:30:23 pm
content: The technique you have described will never work, for several reasons.The first reason is that you haven't accurately described what you need it to do. Once you have done that you will be in a position to use google to see how variable loads are actually implemented.

author: rs20
author_rank: Super Contributor
timestamp: September 21, 2015, 01:35:09 pm
content: Current sense resistor to measure the current, a pot to generate a control voltage,and an opampthat is in control of the base of the transistor, and does whatever it needs to to keep the voltage across the sense resistor equal to the control voltage.This is for your classic constant-current load. But to a certain extent, you can use a microcontroller to dynamically vary the current in response to measured voltage in order to implement constant resistance and constant power.
DC motor and LED, adding circuits for long lasting? - Page 1
Forum section: electronics / projects

author: tlhsglm
author_rank: Contributor
timestamp: May 10, 2025, 09:59:43 am
content: Hi fellows, i want to make a simple project. A constant speed DC motor and LED light is outputs. Motor connected to a shaft, it turns multiple discs. Some are clockwise some are counterwise. the counterwise turning discs turns help of belt and pulley.Motor is 12v geared, turns at 5rpm, probably 37mm. Normally i would go for just connect parallel 12v to both, adding 1n4008 flyback diode. But i want to make this lasts long. So my questions are;1-) Motor will make noise in circuit, do i need to add rc circuit to protect leds? or can i just use 1000uf cap?2-) Since gearbox output is slow, if i add a soft start circuit is it helps solely motor or not?3-) Do you have any extra protection suggestions?

author: tlhsglm
author_rank: Contributor
timestamp: May 11, 2025, 01:43:52 pm
content: up
DC motor control response time - Page 1
Forum section: electronics / projects

author: Achu
author_rank: Contributor
timestamp: December 30, 2019, 03:01:14 pm
content: HiI'm working on a project which uses two motors which spin at slightly different speeds which are derived from a reference speed which may change very frequently. I plan to use separately excited dc motor. Due to the rapid variation of rpm it requires a fast speed of response, say a settling time of .1 to .5 seconds.My questions is if that is possible to attain such high speed of response? If so I would like to know what method(s) to use.Thank you.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 30, 2019, 03:44:31 pm
content: You need to obtain the electro/mechanical equivalent of the motor.https://www.modularcircuits.com/blog/articles/bridge-to-the-far-side/motor-modeling/https://www.sciencedirect.com/science/article/abs/pii/S0142061512003262(this kind of thing, but an actually-accessible article ofc)Tim

author: pwlps
author_rank: Frequent Contributor
timestamp: December 30, 2019, 04:57:05 pm
content: I once did it with a simple PID controller (to be more precise, students did it). There are (at least) two factors limiting the response speed: 1) the inertia of the motor itself: the settling time won't be shorter than the mechanical response time of the motor which itself depends on the available (or rated) drive current/voltage, you might easily get 0.1s for a very small and light motor but for a bigger one you will first need to measure the response time with the PS you are going to use; 2) the update rate of the rpm measurement: I was using a simple IR slot sensor giving the rpm once per cycle, this was enough at high rpm (100Hz) but at low rpm it limited the usable bandwidth and gain of the PID, for low rpm you would need a more precise rotary encoder.

author: jbb
author_rank: Super Contributor
timestamp: December 30, 2019, 07:14:30 pm
content: Watch out for backlash in any gearboxes etc. Suddenly slowing (or worse, reversing) the motor can lead to quite a lot of teth banging into one another.

author: Zero999
author_rank: Super Contributor
timestamp: December 30, 2019, 10:53:57 pm
content: Also be careful when breaking, as the motor controller will inject the energy back into the power supply which can blow up the controller, unless there somewhere for the energy to go to. If the energy can't be stored in a capacitor or battery, it will need to be dissipated in a resistor.Another thing which can help increase the response time is to use a higher supply voltage, than the motor can continuously take, which won't cause any harm, unless it's applied for long periods of time or is excessive, causing the commutator to arc over.
DC Motor Drive - Page 1
Forum section: electronics / projects

author: Tnixsw
author_rank: Contributor
timestamp: January 14, 2023, 10:39:42 pm
content: Hi all,I came across a constant speed controller for a small DC motor as shown in the attached outline.The duty cycle of the square wave input to the NAND gate is fixed at around 85% HI. The threshold detector is adjustable and is set to match the motor characteristics. (in my case by trial and error).When the motor is coasting, the voltage drops as the speed reduces and triggers the threshold detector. The output of the NAND gates goes LO and activates the motor drive output. This saturates the threshold detector and keeps the NAND output LO until the square wave turns it back off again and the process continues.I would like to use this as part of a microcontroller project and just wondering if anyone has seen or used this approach before.cheersTony

author: moffy
author_rank: Super Contributor
timestamp: January 15, 2023, 05:27:19 am
content: It is just Pulse Modulation with feedback, open loop PWM is a little simpler, yours just compensates for say voltage drop due to current i.e. the closed loop feedback. Of course if you had a variable input voltage to drive the motor it would tend to steady the voltage across the motor.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 16, 2023, 09:38:18 am
content: Regular brushed DC motors work pretty good as dynamo's too, so you can measure the Back EMF voltage during the off time of the PWM and read that with an ADC.All motors act a bit differently though. and having an oscilloscope to measure the output voltage changes during the PWM cycle is a help in designing the surrounding circuitry. Usually it's best to measure the back EMF when the PWM has been "off" for the longest time, as the residual effects from the current being pushed though the motor have been minimized at that time.This has already been used 50 years ago, but with discrete circuits and a sample and hold for the feedback. Motor RPM will not be very accurate, as there is a limit to ADC resolution, noise and Back EMF linearity etc.Another method is to take feedback from the ripple caused by the motor commutation. As the commutator has a fixed number of segments, deriving RPM from it can be very accurate, but making a reliable feedback from it can be more difficult.
DC Motor Questions - Page 1
Forum section: electronics / projects

author: Xnke
author_rank: Regular Contributor
timestamp: October 24, 2018, 01:18:59 am
content: So, not like how to control one...I'm running a PWM/H-bridge controller.But, I have a 4-pole, permanant magnet, lap-wound motor. It has four brushes, two + and two -, with the + brushes 180* from each other, and the - brushes 180* from each other, and + and - brushes are set 90* to each other.It is rated for 20v, 20A service, with the brushes wired in parallel. IGNORING HEAT, If I were to wire the brushes in series, would I be greeted with a happy 40V, 20A motor? Would it now run 4 times faster?As far as why we're ignoring heat, the motor has no fan and has an external port on the front housing and the brush housing for a blower to run. If the motor would be happy at 40V, but wouldn't automagically desire the full 20A current, (If current will still be based on load) then having a squirrel cage blower mounted on the rear shaft of the motor would supply plenty of cooling air.I am not finding many details on how 4-brush permanant magnet motors operate, beyond "it will be lap wound and the number of brushes is equal to the number of poles, if it is a high-current motor". Wave wound motors are for "lower current" and only ever need two brushes.Basically I've got a big brushed DC servo motor that is missing the encoder, it's in very good condition (practically new) and I wanna press it into service. Ideally it'd be a 800W 2500RPM motor, but it is a 400W motor that is ridiculously overbuilt with no fan to cool the armature. I *Suspect* it's a 1000RPM motor, but until the motor shop finds me some spare brushes (I wanna have extras if I am gonna run this thing) I won't have it assembled to test and see how the motor reacts to 40V operation.

author: duak
author_rank: Super Contributor
timestamp: October 24, 2018, 07:29:07 pm
content: Here's some observations but no answers. I've got an brushed DC instrumentation motor with two brushes located 90 degrees apart, not 180. I didn't dig too deeply and sort of found out that the armature was wound differently but I don't know why or if there was an advantage. I seem to recall seeing some servo motors in CNC machines that have 4 brushes, all placed 90 degrees apart. Not knowing for sure, I would bet the extra brushes allow for greater current and thus higher short term torque. I'd also bet that the brushes are diametrically at the same potential by way of the armature so I doubt they could be connected in series. However, I don't know for sure. I'd be interested to find out more too.Cheers,

author: jmelson
author_rank: Super Contributor
timestamp: October 24, 2018, 10:35:21 pm
content: Quote from: Xnke on October 24, 2018, 01:18:59 amNO! The armature and commutator are wound to have 4 magnetic poles, and the field is provided by 4 magnets. Without rewinding the armature, you can't change the fact that it is a 4-pole motor. And, the commutator and brushes are set up for the same architecture.Jon
DC motor speed calibration - Page 1
Forum section: electronics / projects

author: XaviPacheco
author_rank: Regular Contributor
timestamp: December 05, 2018, 02:43:35 pm
content: I have seen some treadmills with DC motors that have an option in the console to calibrate the speed sensor by making the motor run from 0 to max speed. Also, some of them have an external potentiometer to compensate torque. When is this calibration needed, or under what condition the system loses calibration?I have designed my own motor controller for this kind of motors, and I used a PI controller microcontroller-based to compute the duty cycle according to the setpoint given. It works well even if the load varies. Do I need to add a calibration option as well? Let's say I use my motor controller with different DC motors ranging from 1 to 4HP. Or let's say I change my speed sensor, and now I have more pulses per revolution than before. I think the system characteristics would vary, right? Is here when calibration comes to play? Maybe I'm using better technology that those old motor controllers and I don't need this?
NE555 DC motor speed control  - Page 1
Forum section: electronics / projects

author: strawberry
author_rank: Super Contributor
timestamp: May 28, 2017, 06:34:26 pm
content: DC motor speed controller/LED dimmer NE555 based PWM learning kithttps://www.tindie.com/products/10008/eBay auction: #302375968418Input voltage range(auxiliary input only) : 15V...28VInput voltage range max(screw terminal only): 0V...50VMAX load current (Ta=25C° ) : 10ArmsInternal SMD fuse : 10AStandby current max(auxiliary input only): 20mALoad regulation(manual potentiometer) : 2...99%Default PWM clock frequency (+/-5%) : 255HzInternal supply voltage(not accessible): 12VInternal supply current(not accessible): 0.5ArmsPCB board dimensions : 54x54mmPower screw terminal:+ :Power supply positive terminalM+:Output positive terminalM-:Output negative terminal- :Power supply negative terminalAccessible ports (header pitch 2.54mm):+: Auxiliary supply input+: Main supply output(with series resistor 10ohm)G : GroundO : NE555 low power PWM outputG : GroundT : Timer ramp voltage(ramp capacitor 100nF to ground)C : Reference voltage control(reference filter capacitor 100nF)R : Reset(pull-up resistor 1k to 12V)G : Ground

author: strawberry
author_rank: Super Contributor
timestamp: July 07, 2017, 08:07:04 am
content: Finished PCB
DC motor speed control replacement (AN6610 vs AN6652)  - Page 1
Forum section: electronics / projects

author: okw
author_rank: Frequent Contributor
timestamp: May 07, 2025, 08:34:33 am
content: I have a tape recorder with a busted AN6610. Can I replace this with an AN6652? I need to short pin1+2 and rotate the IC 180 degrees. But besides that, is it a drop in replacement?Seems quite similar.Reference voltage is 1.25V on AN6652, while it was typically 1.22 on AN6610 - doesn't matter?The application circuit says:Ka:Generation constant=2.4mV/rpm (identical).Ra:Internal resistor = 18 Ω (25 Ω on original AN6610.KT:Torque constant=200g x cm/A (220 on original AN6610).RT is 330Ω vs 470Ω. And a parallell cap over RS. Not sure if they will affect the speed, and I need to adjust anything?(NTE7089 was a drop in replacement, but hard to get, so I prefer AN6652 if possible)

author: jwet
author_rank: Frequent Contributor
timestamp: May 07, 2025, 03:35:53 pm
content: In looking at the data sheets, they do look very similar. I don't think any of the parameters like the voltage matter much- there is a pot that should let you set the speed. I would certain try it. I wouldn't change anything. If you could find an english data sheet, would be easier to completely verity. Good luck. If you're careful with your connections, you should be fine.
DC Motor speed control using PC - Page 1
Forum section: electronics / projects

author: sirai.soft
author_rank: Newbie
timestamp: June 07, 2015, 04:48:07 pm
content: Hithis is project show you how to control DC Motor by your computerattachments:MikroC codecircuit in isisprogram//Video//=================================//project//================================http://www.mediafire.com/download/37q36ve5ycnv2ph/sp+control.rar
DC Motor Speed Q31 PID tuning - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 26, 2017, 01:16:45 pm
content: Hi,I wanted to know how to calculate the PID parameters for Q31 for controlling of my DC motorI have a PWM with lower limit of 1000 and maximum of 2000, if the PWM is below 1000 the motor would simply not run, and also I have a shaft encoder for reading the motor speed, here is a table representing pwm and shaft-encoder speed.Motor PWM Pulse Speed1000 1201100 1951200 2751300 3551400 4401500 5201600 5901700 6501800 7051900 7252000 735I'm using ARM Cortex M3 and I have a PID task with a 10ms sample intervals,here is the code for the taskQuoteThis arbitrary parameters for PID tuner some how works, but If there is a sudden change from ref_Speed for example from 700 to 150 the PID controller would not regulate the output and it will set the PWM to the maximum, so How should we find the parameters? and how we should set them in Q31thanks

author: danadak
author_rank: Super Contributor
timestamp: August 26, 2017, 10:09:01 pm
content: This might help -http://m.eet.com/media/1112634/f-wescot.pdfRegards, Dana,

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 27, 2017, 07:28:34 am
content: Thanks

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 27, 2017, 07:59:35 am
content: Is there a way to tune it using matlab or other similar tools?

author: danadak
author_rank: Super Contributor
timestamp: August 27, 2017, 09:52:54 am
content: Just google "matlab pid tuning", lots of hits.Regards, Dana.

author: mikerj
author_rank: Super Contributor
timestamp: August 28, 2017, 10:15:26 am
content: The arm_pid_instance_q31 structure uses 16 bit variables to hold the gain values, in a fixed point 1.15 format, but the values you are assigning to Kp (2000000000) and Ki (500000000) are both far too large to fit into 16 bits. Your compiler must have warned you about this.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 29, 2017, 05:35:20 am
content: Honey trust me their are 32bit's
DC noise filter  - Page 1
Forum section: electronics / projects

author: ijchan223
author_rank: Contributor
timestamp: June 23, 2014, 05:28:18 am
content: hi , i am working on a dc filter to eliminate some of the noise on a car's dc. have about 1 volt PtP of noise on top of the 12v dc and varies from 30 hz to a couple Khz. i didn't calculate values for the parts yet they are just random values right now but would the concept work ? or is there a better approach to try to eliminate the noise. ?
DC offset on both channels of amp - Page 1
Forum section: electronics / projects

author: pringe
author_rank: Newbie
timestamp: June 28, 2023, 10:55:13 am
content: Hi there - I am trying to fix an issue on the amplifier section of an old Yamaha Electone HS-7 organ.I've got the amp board on the bench powered from a bench supply, and at +/-26VDC both channels show approx -4.5VDC offset. These circuits use the old Sanyo amplifier module chips (this one is an STK4026II) and I assumed they were blown but having bought replacements the issue remains, with the same amount of DC offset present. The fact that both channels show the same amount of DC offset is puzzling me too. I've checked all components around the module and can't see any trace damage / cold solder joints etc.I've attached a schematic of the power amp section, and the equivalent circuit diagram of the power amp module.I'd be really grateful for any pointers of what might be going on here from someone with better knowledge than me of these amplifier circuits! One thing I have noticed is that pin 5 of the amp modules (at the emitters of what looks like a current mirror?) is sitting at approx -5vdc, so approx 200mA through the 100R resistor from the negative rail. Does this seem like too much?Thanks in advance

author: wasedadoc
author_rank: Super Contributor
timestamp: June 28, 2023, 11:09:01 am
content: Have you checked that 100uF cap from pins 5 to 0 Volts for electrical leakage?

author: xavier60
author_rank: Super Contributor
timestamp: June 28, 2023, 11:46:13 am
content: The 100R resistor must be open.

author: magic
author_rank: Super Contributor
timestamp: June 28, 2023, 01:17:43 pm
content: That's possible. If it isn't open, it must be getting quite hot dissipating 4W.If it's not the resistor, post voltages at pins 1 to 6.

author: wasedadoc
author_rank: Super Contributor
timestamp: June 28, 2023, 02:10:41 pm
content: Other than the power rails there is nothing common between the two channels except the single 100 Ohm resistor and single 100uF capacitor feeding pin 5 on both modules. Note that the resistor is FR type, ie fusible.

author: pringe
author_rank: Newbie
timestamp: June 28, 2023, 02:17:31 pm
content: Dohyes of course it was the 100R resistor gone high, just checked and it measures about 15K. The 100R on the other rail had also gone high but not as much. Thanks guys. Been chasing my tail with this one a bit, I think from memory originally the modules were going fully to -ve rail on output (the initial fault) but at some point these 100Rs must have given up and I hadn't noticed since initially checking. Progress! Thanks again
DC offset on floating pins. What to do? - Page 1
Forum section: electronics / projects

author: mkiijam
author_rank: Regular Contributor
timestamp: May 27, 2024, 05:31:05 pm
content: I have this little circuit that uses a THAT 12XX series line receiver. I plan on switching the chip in and out of circuit with a relay, but this operation will leave the chip's output "floating." The next stage is AC coupled and I fear there may be a build up of DC that I should keep at 0Vdc. Should I add 100k-1MR someplace?See schematic.

author: Zero999
author_rank: Super Contributor
timestamp: May 27, 2024, 09:14:34 pm
content: Leaving the output floating is fine. It's normally floating inputs which are the problem, but the ICs you're using have their inputs internally biased, so it's a non-issue.https://thatcorp.com/datashts/THAT_1200-Series_Datasheet.pdfhttps://www.thatcorp.com/datashts/THAT_2180-Series_Datasheet.pdf

author: Benta
author_rank: Super Contributor
timestamp: May 27, 2024, 10:40:25 pm
content: Forget it. The only troublemaker could be the input cap to the next stage, but your transformer will set the DC level when the IC is switched out.
DC Power Connector Identification - Page 1
Forum section: electronics / projects

author: morphis
author_rank: Newbie
timestamp: July 21, 2015, 01:22:15 am
content: HiI have a Eaton 5PX UPS.Eaton used to make an external battery breakout connector so bulk lead acid batteries could be connected, rather than the 1-4 Eaton EBMs ( External Battery Modules ).As I can not find the breakout connector any where now, I'm trying to find out if this DC connector on the back of this unit is available somewhere.Its the large 5 pin connector in the centre. ( 48 VDC , 55 A )Spent hours looking with no luck so far. It maybe a custom Eaton connector.If it is, I'll have to mod the UPS and install a standard Anderson connector.

author: TheMG
author_rank: Frequent Contributor
timestamp: July 21, 2015, 05:27:17 am
content: Most Eaton UPS use Anderson Powerpole connectors but there are indeed a few models that use proprietary connectors.So although I'm not entirely familiar with the 5PX, it is quite possible that is proprietary seeing as some of their other models have had proprietary connector in the past.

author: morphis
author_rank: Newbie
timestamp: August 24, 2015, 12:38:58 pm
content: I recently scored a Powerware 9120 700VA and Powerware 9120 1000VA, That have the same external battery connector.Details on the connector30A 250VDCPPC 25R-5-AWELL SHINSeams Well Shin is a Taiwanese power connector manufacture though I have not been able to find out anymore info yet.Pinout is:___________________| Neg Neg || || Earth || || Pos Pos |--------------------------And 4mm banana plugs fit perfectly.I'll 3D print a plug assembly to hold 5 banana plugs.

author: tkuhmone
author_rank: Regular Contributor
timestamp: January 21, 2017, 03:26:23 pm
content: Hi morphis,Just interested to ask, did you already manage to add DIY external 4*12V battery to your Eaton 5PX UPS ?I am interested of this, since I also own 5PX series UPS (5PX2200iRTN).Maybe some future I could consider getting extension battery pack to it. One option may be to try find a used enclosure and buy new batteries to it. I understood the new (and original Eaton) battery packs are highly priced.In the panel of 5PX series, there is modular RJ-connector named as "to battery cabinet". Does the DIY external battery even work, if detection connector is not used ?The battery (at least for 5PX2200 -> type 5PXEBM48RT) has mentioned standard supplied accessories "EBM detection cord".I have a now (unfortunately) a faulty 5PX UPS in my hands, battery charging failure alarm seenThe unit is little bit over one year old. Estimated arrival of replacement unit will be in next 1...3 weeks.