hybridfree/eevblog-posts huggingface dataset:
low pass filter noise ? best is passive or base on a op amp ? - Page 1
Forum section: electronics / projects

author: Overspeed
author_rank: Frequent Contributor
timestamp: August 12, 2024, 07:41:23 am
content: HelloSome op amplifier provide very low noise but when a low pass filter is added that generate noise ( after amplification OK ) SO :Does there is designs requirements to built a low noise filter as a low pass 150 Hz filter ?A common way is to fit a passive resistor + cap at the op amp output as described in Analog / TI docsRegardsOS

author: Benta
author_rank: Super Contributor
timestamp: August 12, 2024, 10:48:23 am
content: Noise has much more to do with which opamp you select than anything else.The output RC filter is there for a completely different reason: to make the LPF behave.Active LP filters turn into HP filters at a certain frequency. The RC output filter cures that to some extent. Sallen-Key filters are especially bad in this respect.Check the TI application note sloa049d.pdf for a full explanation (p.14).

author: Kleinstein
author_rank: Super Contributor
timestamp: August 12, 2024, 06:57:05 pm
content: With good op-amps, just the natural resistor noise can get significant. For lowest noise one may have to use a rel. small resistor and larger capacitor.

author: TimFox
author_rank: Super Contributor
timestamp: August 12, 2024, 08:18:51 pm
content: To understand this question quantitatively, one needs to include the source impedance driving the filter circuit.

author: Overspeed
author_rank: Frequent Contributor
timestamp: August 13, 2024, 06:25:56 pm
content: Quote from: TimFox on August 12, 2024, 08:18:51 pmHelloThat for resistivity material measurement a voltage from a 4 wires resistance setup so resistance is low to very low and I think can be considered as pure resistiveThe Op Amp is AD8421 or AD8458 I have also a dual OPA 189 circuitRegardsOS

author: Overspeed
author_rank: Frequent Contributor
timestamp: August 15, 2024, 11:14:02 am
content: HelloAs I am limited in time I will use a passive filter ( resistor + cap ) as described in Analog doc that easy , quick to install and a proven solution later I will set an active filterRegardsOS
Low power (<10uA ideal) Ideal diode, up to 13v - Page 1
Forum section: electronics / projects

author: Tangent_Tracker
author_rank: Regular Contributor
timestamp: April 11, 2024, 11:06:03 am
content: So as per the title, all the ideal diodes that are low power consumption seem to cap at 5v5, maybe 6, but I would like one that caps at minimum, 13v (3 lipos series, so 12v6 to be exact), current 500mA would be nice but ok with about 100mA, so not asking a huge amount!While I can find these, they stop caring about supply current which goes into the hundreds of uA!Anyone got any suggestions please?

author: xvr
author_rank: Frequent Contributor
timestamp: April 11, 2024, 11:40:01 am
content: P channel mosfet is not enough?

author: Tangent_Tracker
author_rank: Regular Contributor
timestamp: April 11, 2024, 09:07:05 pm
content: trouble is, all circuits have leakage to ground via resistors and transistors etc...

author: PCB.Wiz
author_rank: Super Contributor
timestamp: April 11, 2024, 09:12:24 pm
content: Quote from: Tangent_Tracker on April 11, 2024, 09:07:05 pmThere is an inherent speed / power trade off.How fast do you need this to work, and how dynamic is the reverse operation ?eg a circuit like this can be scaled for speed/current trade off.https://www.powerelectronictips.com/inexpensive-ideal-diode-mosfet-circuit/Addit: One caution with that circuit, the reverse base-emitter breakdown needs watching at higher operating voltages.Diodes Inc have a DZDH0401DW, that claims 40-50V reverse so presumably they address that.

author: spostma
author_rank: Regular Contributor
timestamp: April 11, 2024, 09:25:39 pm
content: Microsemi SFDS1045LH ideal solar diode might be a suitable choice: 0.5uA @ 45V leakage current / max. 10A forward current

author: Tangent_Tracker
author_rank: Regular Contributor
timestamp: April 16, 2024, 12:41:40 pm
content: That looks a good option, I was hoping for something all in one package tbh, but beggar's and choosers and all that!
Low power 3,6 and 12 phase systems - Page 1
Forum section: electronics / projects

author: CM800
author_rank: Frequent Contributor
timestamp: February 02, 2014, 12:00:55 am
content: Hello folks,Im interested in having a mess around with phased electronics (running at low voltages) as im just fairly curious about these things.Does anyone know how to generate the delays in phase for the bridges in invertersI know that3 phase is 120 out of phase6 phase is 60 out of phase12 phase is 30 out of phaseDegrees out of phase = 360 / phasesi can therefore calculate the time dealy between each phase, but i am unsure as how to generate the time delays from my base square wave,would someone reccomend a chip or diagram to help me with thisHuge thanks!TCW

author: johnwa
author_rank: Frequent Contributor
timestamp: February 03, 2014, 09:15:20 am
content: Hi,I have been looking at doing something along these lines myself, for testing some three phase circuits. You speak about square waves, are you looking at using some sort of switchmode output stage? You may be better off generating sinewave signals, and feeding them through linear power amplifiers. This will be somewhat inefficient, but probably acceptable for this application.One approach is to start off with a single phase sinewave, and phase shift it using R-C networks to generate the three phases. I think Mike did a video on this for powering a three phase gyroscope motor. This is probably OK if you want a fixed frequency, but it will be a bit difficult to maintain the correct amplitude and phase if you vary the frequency.Alternatively, a phase shift oscillator can be configured so that it is symmetrical with respect to the three phases, and all three waveforms are generated simultaneously. See for examplehttp://www.4qdtec.com/wfg.html. This circuit gives a square wave output, but I imagine it could provide a sinewave signal if suitable amplitude stabilisation was used.

author: jwm
author_rank: Regular Contributor
timestamp: February 03, 2014, 10:12:03 am
content: Quote from: TCWilliamson on February 02, 2014, 12:00:55 amI use a 4017 for something like this and use or gates on the outputs to build multiple arbitrary synchronized waveforms.John

author: qno
author_rank: Frequent Contributor
timestamp: February 03, 2014, 02:27:47 pm
content: Check out some theory about BLDC drivers.3 phase motor control is done nowadays with a microprocessor or a dedicated chip.Almost all microprocessor manufacturers have a 3 phase motor control app note.Checkout Microchip, Atmel or any other of your favorite microcontroller manufacturer.If you understand the principle it is quite easy to translate the 3 phase signal to 6 or even 12 phase.Asuming you need 6 outputs to control the low and high switch of a 3 phase system you will need 12 for a 6 phase and 24 for a 12 phase system.There is also loads of info on youtube. Search for "VFD" and some Indian professor will tell you all about it.
Low Power Consumption TFT display design-in - Page 1
Forum section: electronics / projects

author: FutureDisplayTouch
author_rank: Newbie
timestamp: October 11, 2025, 09:54:04 am
content: I am thrilled to share some exciting news with you today!We have successfully lit up a new reflective type of display that features a 4.2-inch size with a resolution of 300 × 400 pixels.This technology is superior for applications where low power, always-on visibility, and excellent performance in bright light are the highest priorities.

author: cunningfellow
author_rank: Regular Contributor
timestamp: October 12, 2025, 10:57:05 pm
content: Your post is SPAM, but it is as least spam I am slightly interested in.Please provide some more details before you go off and spam other people.

author: FutureDisplayTouch
author_rank: Newbie
timestamp: October 13, 2025, 06:27:27 am
content: I'm sorry if the post came across as spam — that was certainly not our intention. We were simply excited to discover an alternative full-color, energy-saving display technology that rivals e-paper, and wanted to share it with fellow electronics professionals who, like us, are committed to protecting our planet.The technology works by using specialized source and gate driver ICs to adapt TFT technology for always-on display scenarios. Additionally, by incorporating a reflective film, the need for a backlight is eliminated — the TFT screen content is instead displayed through reflection, achieving excellent visibility in sunlight. Of course, for low-light environments, a front light with a light guide panel can provide efficient illumination (similar to Kindle's front-light technology) while remaining energy-efficient.I also attached an image of us testing this new display, but unfortunately it wasn't shown — likely flagged as spam, just as you mentioned.
Low power input electric motor 67 miliwatts. How to improve it ?  - Page 1
Forum section: electronics / projects

author: st12
author_rank: Newbie
timestamp: December 21, 2018, 09:09:48 am
content: I managed to build a low consumption electric motor 67 milliwatts powered with a single small solar panel VIMUN SC 3012 - 2A (also inside an office calculator) exposed in artificial light. It consists from a small solar panel, electronic circuit , air core and a neodymium sphere 19 mm diameter 27 g.Probably you will wonder why ?I am looking forward to make a Dc generator. A joule thief, converter, step up booster will not start using the tiny mentioned input.Details : neodymium sphere 19 mm diameter - the key component Material NdFeB Shape, Sphere Diameter 19 mm Tolerance +/- 0,1 mm, Coating Chrome-plated (Ni-Cu-Ni-Cr), Manufacturing method sintered Magnetisation N38 Strength approx. 4,9 kg (approx. 48,1 N), Max. working temperature 80°C, Weight 27,2943 g, Curie temperature 310 °C, Residual magnetism Br 12200-12600 G, 1.22-1.26 T, Coercive field strength bHc 10.8-11.5 kOe, 860-915 kA/m - position of the poles up and downThere are a total of four electrical components. A small solar panel ( VIMUN SC-3012-2A, 29.44mm×11.6mm×1.1mm, 4 cells. The following specifications were listed, 2.0 Vos, 9.0 UAsc, 1.5 Vop, at 200Lux), a 470 uF 10 V electrolytic capacitor, a coil iron less with thin copper wire and a small circuit board with a black blob on it. Under this blob is the integrated circuit chip (HT111A1)the electrical components ( excepting the coil are from a solar toy )ThxSt

author: Ian.M
author_rank: Super Contributor
timestamp: December 21, 2018, 10:07:18 am
content: To improve motor efficiency you'd need a closed magnetic circuit with pole pieces shaped to fit the sphere and minimised core volume to reduce hysterisis losses (but with enough core area to avoid saturation), minimal air gap (maybe 3x the sphere diameter tolerance), and much better bearings - probably jewelled.

author: st12
author_rank: Newbie
timestamp: December 21, 2018, 10:58:45 am
content: Hello Ian !Thx for the answerI wish to mention that, I already avoid the friction ( excepting the one with the air ) as much as possible + glass. The friction is present only at the contact with the glass and is minimal. I am looking in the direction of the capacitor and coil. What is strange is that the motor is running with the poles orientated up and down like in the attached diagram (attached in the first post ). If I move the orientation of the poles, the sphere is vibrating (no rotational effect )Thx St
Low power isolation transformer for high voltage potting distance - Page 1
Forum section: electronics / projects

author: daqq
author_rank: Super Contributor
timestamp: February 25, 2016, 03:16:02 pm
content: Hi guys,I need to make a low power (<8W) isolation transformer that will isolate the primary side from the secondary side for high voltage (max 14kV, short pulses). I have never done such a thing.At the moment I am planning to use 2 PCBs with a coil in the pattern placed above one another with the core in the middle. There is a 1cm distance between the primary and the secondary PCB in height.What worries me is the distance between the edge of the PCB and the transformer ferrite core - at its lowest point it's around 1.5mm (and the closest copper pattern is 1.7mm) from the ferrite core. The ferrite is not exactly a great conductor, but still is conductive-ish - as such I assume it should be treated as an electric path. So the smallest distance between the primary and secondary side would be 3.4mm, assuming the core as a connection.The whole thing will be well potted in vacuumed epoxy with a dielectric strength of >20kV/mm - so there would be two 'walls' of 1.5mm epoxy between the primary and secondary. As such I assume that it should survive the voltages.Ideally, I would make this much larger, but, space is a luxury in this case. Do you think this is an acceptable design?Thank you,David

author: Siwastaja
author_rank: Super Contributor
timestamp: February 25, 2016, 03:40:41 pm
content: You are right that the ferrite core needs to be considered as conducting material with high voltages.In any case, your epoxy potting must be spot-on and leave no air gaps anywhere. Otherwise, corona discharges tend to happen in those air pockets. Discharge itself and ozone produced by the discharge embrittles the epoxy and other isolation materials (soldermask on PCB, in this case).

author: daqq
author_rank: Super Contributor
timestamp: February 29, 2016, 08:49:07 am
content: Thanks, I assumed that no bubbles would be allowed - as such I am planning to completely clean and deoil (against fingerprints and other nasties) and bake (to remove any moisture trapped inside of the PCBs) the thing before potting, then pot it with epoxy (vacuumed before that), then vacuum the whole potted transformer assembly to get any remaining air bubbles out of it and then leave it to dry long.By the way, the transformer has around 1:1 voltage ratio - one side will just be pulse offseted to higher voltages.
Low power, low quiescent step-down from 65V to 40V? - Page 1
Forum section: electronics / projects

author: asymcon
author_rank: Contributor
timestamp: May 07, 2020, 03:04:21 pm
content: Hi there,I need to work around a 53V limit of a LDO on a specific board by injecting it 40-ish volts, while the rest of the circuit gets full 65V.And I'm a bit struggling to get 40V out of 65V in (somewhat) simple design.Project requirements are these:sub 1mA quiescent current, ideally zero (this preregulator will be always connected to battery)at least 50mA output current (30mA expected maximum, with some reserves)stable output at 40V, regardless of what is the input voltage (always above 40V, but discharged battery will be 45V)With such small currents, both LDO and switching regulators are good, but getting the quiescent current below 1mA is crucial.I tried to play with TL783, but couldn't get anywhere, based on R2 value, it sucks up to 5mA from the source.Is there a simple or ready-made solution for this?Thanks!

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: May 07, 2020, 03:07:30 pm
content: Series string of zeners?

author: asymcon
author_rank: Contributor
timestamp: May 07, 2020, 03:12:11 pm
content: Quote from: pardo-bsso on May 07, 2020, 03:07:30 pmMight work, but I forgot to mention, that the 40V out should be if possible, stable, regardless of input.

author: unitedatoms
author_rank: Frequent Contributor
timestamp: May 07, 2020, 03:18:16 pm
content: Consider following shunt regulator like classic Zener, but with current limiter instead.+60V->LT3092(tuned to 0.5mA, bypassed by 20-30V Zener to protect it)->reference resistor bypassed with capacitor->ground.At top of reference resistor you get exactly say 41V (by choosing a resistor). Tap this point with base of Darlington emitter follower, with say 10k resistor at base.Edit: or shunt regulator with pair of LT431 20V each and emitter follower.

author: eliocor
author_rank: Unknown
timestamp: May 07, 2020, 04:24:03 pm
content: I never had problems with theLM5165(11µA no load quiescent current).Unluckily its max input voltage is just 65V....

author: asymcon
author_rank: Contributor
timestamp: May 07, 2020, 05:03:55 pm
content: Found possibly best solution for this -> TPS7A4001100V, ultra low IQ (just few uA) and 50mA max output.But I miscalculated and it turns out I'll need close to 100mA.Would enhancing the heat dissipation abilities of TPS7A4001 would allow it to operate at 100mA (typ. current limit kicks in at 117mA)?http://www.ti.com/lit/ds/symlink/tps7a4001.pdf
Low power low voltage cap discharge issue preventing MCU boot. - Page 1
Forum section: electronics / projects

author: saber63
author_rank: Newbie
timestamp: August 14, 2025, 03:48:51 pm
content: A simplified schematic is attached. The issue is that when the battery is removed the circuit drains down to ~0.7v and then just hangs out... For ever.... Like 15+min... (There may be additional leakage from another dc-dc's enable pin back to the MCU, but thats not the main point of the discussion)This 3.3v rail not getting close enough to 0volts prevents the 32.768khz TCXO from turning on when power is returned!We dont want to just slap on 1meg resistance as our entire system power aims for ~170uA average.Trying to think of a low voltage cutoff circuit or chip that would either cleanly remove the 3v3 power below say 2.5v. or some how only draw current below 2.5v to bleed off the caps quicker...Other ideas would be to power the txco from the mcu... But im not sure the gpio wont float to ~0.7vThanks!

author: SteveThackery
author_rank: Super Contributor
timestamp: August 14, 2025, 09:36:04 pm
content: I can't see the battery in the diagram. But a 1M resistor will only add 3.3uA to the 170uA already drawn. Seems too small to worry about.

author: thm_w
author_rank: Super Contributor
timestamp: August 14, 2025, 10:16:57 pm
content: Does toggling the EN pin on the TCXO work to wake it up? Or is it still stuck in that frozen state.

author: saber63
author_rank: Newbie
timestamp: August 14, 2025, 10:20:50 pm
content: The 7.2v on the left is the battery/incoming power.The concern is that even with a bleed resistance of manageable size, the sub 1 volt error window would be long enough to get caught when plugging in power source die contact or switch boucing. Yes the occurrence rate would drop from every time to.... Still possible...Id like it to not be possible.The enable pin is an excellent question, will need todo some rework to test. But will do!Thanks!

author: Psi
author_rank: Super Contributor
timestamp: August 14, 2025, 10:36:52 pm
content: You can get chips designed to cleanly startup/shutdown ICs via enable/reset pins based on voltage and some delay.TC51 comes to mind, but there are lots of them. TC51 draws 1uA I think.They're often called voltage supervisor ICs or Reset ICshttps://www.microchip.com/en-us/product/TC51Actually you probably want one that cuts off a bit lower than that one.

author: saber63
author_rank: Newbie
timestamp: August 15, 2025, 08:28:44 pm
content: Ah! Yes! Thats the family of chips I was thinking of!The TC51 looks pretty spot on actually, ill shop around a bit as well.Thanks!
low power OCP and OVP and CC  - Page 1
Forum section: electronics / projects

author: eevblogfan
author_rank: Frequent Contributor
timestamp: April 16, 2013, 07:28:37 am
content: heyjust thought about it , CC uses MOSFET for high power stuff . the benefit is perhaps speed and low gate drive current , but the drawback for sensitive stuff is the ringing or over shoot ( mine over shoot exactly 5 times from the set current , does any one know why the constant 5 is into play ? )now I can't remember the period of the over shoot of mine CC but I think it was in the uS region , and I am pretty sure some silicons don't like few tens of uS of several times more the current needed/allowed ,so the solution is using transistors right ?they should be slower and much more the "linear" version of that purpose , am I right ?the drawback is current on the base , but that what you pay for good linear and no over shoot result . am I right ?thank in advance !
Low Power Optical Mouse Sesor?? - Page 1
Forum section: electronics / projects

author: roboticsound
author_rank: Newbie
timestamp: August 27, 2016, 02:12:47 pm
content: Hi All,I was hoping someone could help point me in the right direction to find a low power sensor to use in an optical mouse. Avago did produce a line that seemed interesting but all appear to now be obsolete. I have now been looking at this rangehttp://www.avagotech.com/products/optical-sensors/integrated-ambient-light-and-proximity-sensors/but I get the feeling that these are a bit overkill for a mouse. Really for this application power is a big concern.Anyway, if anyone has any input it would be much appreciated.Thanks

author: Marco
author_rank: Super Contributor
timestamp: August 27, 2016, 08:20:17 pm
content: Those are not Doppler or image sensors, they won't be able to do surface tracking.I'd assume the Philips sensors are lowest power, but I'm not certain.
low power psu - Page 1
Forum section: electronics / projects

author: Terry Bites
author_rank: Super Contributor
timestamp: May 11, 2021, 08:36:12 am
content: I wanted to make a fairly precise psu for a few mA and up to 9V. My bench PSU is to coarse and a calibrator too expensive as a low use item . So I went down the easy route, a current source supplying a voltage follower.I wanted a good tranisent response and simple programming from input voltages, pots or PWM.It works! No precision resistors. The current source is easily tweaked at R3,R4 or R5.I'm sure it can be improved on, but I made it from what was to hand.

author: David Hess
author_rank: Super Contributor
timestamp: May 11, 2021, 04:43:37 pm
content: I really like that method of level shifting the current control signal to a high side error amplifier, but the second and independent source follower for voltage control is redundant; both the current and voltage control loops can be combined with a single source follower or common source pass element. See figure 6 on page 29 of the LT1366 for an example where only a single pass MOSFET is required.

author: Zero999
author_rank: Super Contributor
timestamp: May 12, 2021, 09:27:15 pm
content: Bear in mind that C13 will help the constant voltage mode, at the expense of constant current mode.If it's just a few mA, then why do you need any pass transistors?
Low power redundant power supply switch??? - Page 1
Forum section: electronics / projects

author: dazz1
author_rank: Frequent Contributor
timestamp: May 01, 2019, 01:49:10 pm
content: HiI have a project that has a small module that draws 30mA @ 3.3VDC. I need the module to be able to select it's power supply. One supply is 3.3VDC, and the other supply is nominally a 12VDC LiFe battery. I need to be able to seamlessly switch between the 2 supplies.All the search words I try to use to find a suitable circuit/device don't have the right outcome. Any suggestions cPlease help.

author: dazz1
author_rank: Frequent Contributor
timestamp: May 07, 2019, 05:27:49 am
content: HiI figured out I can do this with ideal diodes.Dazz

author: Ian.M
author_rank: Super Contributor
timestamp: May 07, 2019, 06:09:26 am
content: I presume you are regulating the battery supply down to 3.3V. A pair of ideal diodes wont do what you want reliably as the supply with the fractionally higher voltage always 'wins'. e.g. if 3v3in=3.30V and 3V3batt=3.31V, it will never draw current from the 3.3V input, so will flatten the battery.What you actually need ts a circuit that monitors the 3.3V input, and if present connects it to the load via a mosfet and simultaneously disconnects the battery via another MOSFET, or possibly by disabling the battery 3.3V regulator via its enable pin, (but that regulator must then tolerate 3.3V on its output when disabled - check datasheets carefully).

author: dazz1
author_rank: Frequent Contributor
timestamp: June 07, 2019, 10:08:24 am
content: HiI have a new solution.Drive a single 3V3 LDO through 2 diodes from 2 separate 5V supplies.I need the LDO anyway.Dazz
low power sensor output interface to MCU - Page 1
Forum section: electronics / projects

author: littleboot
author_rank: Regular Contributor
timestamp: June 06, 2018, 01:41:51 pm
content: Hello,I'm currently working on a project and I need to connect a sensor output to the MCU but I would like to make this as power efficient as possible.I attached a image of the sensor out from the datasheet.the second image is a configuration were I connected a resistor across the base and emitter of the transistor. This circuit seems to work inside the simulation but I don't really get why it works.R5 10000K = I/O imput impedanceR1 25K = interal pulldown (can't be turned off in MCU stanby mode)the last image is how I connected it the first time, this circuit also works but uses more current.Could some explain which circuit config is superior, and why.thanks in advance

author: Marco
author_rank: Super Contributor
timestamp: June 06, 2018, 02:06:58 pm
content: What is happening in the first circuit is that the transistor base-emitter junction acts like a diode with the sensor delivering all the current ...The second is better, but you don't need R4.
Low power serial interface - Page 1
Forum section: electronics / projects

author: Pedro
author_rank: Newbie
timestamp: March 01, 2011, 10:16:19 pm
content: Hello everyone!I am designing a low power device and it needs to have a full 232 DCE port. The device has a power consumption of 36mW, but when I plug the 232 port to a Pc it goes up to 100mW!!!My best guess right now is that the 232 inputs have a 3k input resistance, which combined with the efficiency of the driver for all four outputs, make such a power loss to happen.What seems funny for me is that all drivers have such input impedance being low power, I would expect to have some high impedance drivers in the market.Anyway, I would like to hear from you, which is your favorite comm interface for low power devices??See ya!!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 02, 2011, 12:33:44 am
content: The trick is to turn off your transceiver when not in use if possible. If not, and low power draw is more important than maximum compatibility then use 0v/5v levels. The power draw is coming from driving -v into the PC's terminating resistors in idle.I've never come across a serial port that didn't work fine with 0v/5v levels.Maxim and probably others do some RS232 transceivers with various smart power-saving features - probably worth a look at these.Another approach, if you have control of the handshake lines of the thing you're connecting to, is to use these to provide the signal levels, e.g. using analogue switches or transistors.

author: scrat
author_rank: Frequent Contributor
timestamp: March 02, 2011, 02:14:45 am
content: Voltage levels are the (maybe unavoidable) cause.I was writing this simple calculation, in the middle Mike posted his one, which I agree.For 4 bits, considering that the output level is always + or - V, power dissipated into 3k loads will be Pdiss = V^2/3k * 4. For classical V=12V, 12^2/3k * 4 = 192mW. For V=5V, 5^2/3k * 4 = 33mW.If it has to be a fully compliant with RS-232, there is no way other than turning off the driver when not needed.
Low power standby "MOSFET"  - Page 1
Forum section: electronics / projects

author: tchiwam
author_rank: Regular Contributor
timestamp: January 17, 2021, 03:58:05 pm
content: I have a design request here, low power battery driven.The reference design is using a Si2323DS and Si2303DS. 3.7 Battery, 3.3V logic...Now I am trying to the lowest power consumption while in the off state. I looked at most Idss, and it everyone seem to stay in the 1µA.Any other ideas of Mosfet or better On Off switch ? I even looked at low power relay switches... I am stuck at 1µA...My RTC takes 45nA, and that is doing something active ... Must be a better way.

author: David Hess
author_rank: Super Contributor
timestamp: January 17, 2021, 06:33:49 pm
content: Datasheets specify 1 microamp because it costs more to test at lower currents. In practice the leakage current is orders of magnitude lower.
Low power step-up DC-DC converters - Page 1
Forum section: electronics / projects

author: ataradov
author_rank: Super Contributor
timestamp: May 08, 2016, 08:03:49 pm
content: I need to get +/- 12 V (+/- 9 V may work as well) from +5 V (USB) supply. I'm looking for the simplest solution, since requirements are pretty relaxed. The current consumption is minimal, all it has to do is power 4 op-amps used for signal buffering and conditioning before the ADC. The ADC is slow MCU ADC, so none of that needs to be high-performance.Is there a to go solution for this sort of application? Full front-end designs for low-end ADCs I should have look at?The design is price sensitive, so expensive out of the box modules may not be ideal, but that depends on the price difference with discrete components.

author: mariush
author_rank: Super Contributor
timestamp: May 08, 2016, 09:19:12 pm
content: A couple of MAX1720 would do the trick ... It can be configured for both negative doubler or positive doubler, so you'd get about +/- 10v (depending on current and diodes chosen)Datasheet:http://www.onsemi.com/pub_link/Collateral/MAX1720-D.PDFTC7660 would also work :http://ww1.microchip.com/downloads/en/DeviceDoc/21465C.pdf

author: PartialDischarge
author_rank: Super Contributor
timestamp: May 10, 2016, 02:05:53 am
content: Use a LT8410 or a TPS61046 , both are boost converters, no problems getting +24 out of 5. Afterwards since youre already using opamps get the ref 0V with a divider/follower, to obtain +12,0,-12.Low component count that will cost around 2-3€ depending on qtys.I actually used these ones cause they have near zero consumption at shudown, but the offer is wide.Ended up using Texas Instruments since its easier to source from MouserEdit: forgot to mention, from what I remember the LT8410s output seemed cleaner with less switching noise than TIs, in my case it wasnt a concern...

author: ataradov
author_rank: Super Contributor
timestamp: May 10, 2016, 03:39:38 am
content: Thanks, everyone. I'll save those recommendations for future projects. This one got changed, so now handling 0-3.3v is sufficient, so the whole thing became much easier. I'll just use LM324 + 5V from USB and that will cover all my needs.
Low power wifi chipset? - Page 1
Forum section: electronics / projects

author: convex
author_rank: Newbie
timestamp: April 22, 2021, 04:57:29 am
content: I'm looking for recommendations for a WiFi chipset to be used in a project I'm working on. I'll be using the chipset to periodically monitor nearby WiFi APs and routers, looking only for SSID and RSSI information. Device is battery battery powered so low power consumption is important.Must have:- low power sleep- rx mode ideally as low power as possible- tx won't be used at all so RF power is not importantThanks!

author: IamSynthetiC
author_rank: Regular Contributor
timestamp: April 22, 2021, 09:33:21 am
content: The esp32 seems to have everything you need. The SoC board (ESP-WROOM-32 i think) is cheep anought that you can throw it in almost anything. Or if you only want the IC you can go for the EPS8266.i hope these suit you.~Best of luck

author: Peabody
author_rank: Super Contributor
timestamp: April 22, 2021, 01:37:14 pm
content: I believe the ESP32 and ESP8266 are 2.4GHz only, in case that matters.
Low Power Wireless. - Page 1
Forum section: electronics / projects

author: forneverban
author_rank: Newbie
timestamp: September 05, 2012, 09:14:13 pm
content: I am looking for something similar to Wixel that uses xbee/custom low power wirelessto use in an embedded project.

author: jeremy
author_rank: Super Contributor
timestamp: September 05, 2012, 09:51:48 pm
content: Why can't you use either of these ?

author: forneverban
author_rank: Newbie
timestamp: September 05, 2012, 09:58:04 pm
content: I answered my own question with your help.

author: notsob
author_rank: Frequent Contributor
timestamp: September 05, 2012, 10:12:12 pm
content: There is also a chinese 433MHz module - Dorji DRF7020D13 - refer to article in Silicon Chiphttp://siliconchip.com.au/cms/A_112748/article.html
Low Power Zero Crossing Detector Uses Auxiliary Voltage From Flyback - Page 1
Forum section: electronics / projects

author: chris_leyson
author_rank: Super Contributor
timestamp: July 25, 2020, 11:48:15 am
content: Given the importance of reducing standby (OFF) power consumption in many household appliances, here is my best effort so far at a 50/60 Hz zero crossing detector. To be fair all the credit should go to Robert W. Hilsher for his design idea "A Unique Discrete Zero-Crossing Detector" EDN 1999.In the attached LTSpice schematic, voltage source V1 represents the 115/230VAC line input, D1 to D4 is the bridge rectifier supplying a small flyback SMPS and voltage source V2 represents its auxiliary supply. Note: Resistor R2 is included to load the bridge rectifier so that D1-D4 simulate correctly.Power consumtion for the cicuit shown is a little over 13mW, 11mW for the AC drive into R1 and about 2.5mW supplied by the SMPS auxiliary supply driving the opto-coupler LED D6 at a peak current of around 1mA. Bench measurements agree well with the simulation and the circuit has been tested at 300VAC line voltage, and all the way down to 20VAC, that's due to the Sanken STR4A164 flyback. Not yet tested for surge or fast transients so some additional protection may be needed. Back end signal processing on the secondary side, opto output, is not shown but adds a few mW.EDIT: Schematic corrected for correct AC line voltage.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 25, 2020, 04:03:35 pm
content: Have you considered a capacitive voltage divider?

author: chris_leyson
author_rank: Super Contributor
timestamp: July 25, 2020, 06:51:01 pm
content: Hi NiHaoMike, to honest yes, however, at the time I was using a different zero crossing detector. A variation on "Mains-driven zero-crossing detector uses only a few high-voltage parts" again from EDN. Resistor values were chosen to provide about 1.5mA opto-coupler drive and power consumption was about 45mW at 230VAC or 800uA opto drive and 12mW at 115VAC.Unfortunately the circuit arrangment doesn't work with capacitive voltage dividers, it needs its own separate bridge rectifier and it uses half or full wave rectified sine drive depending on how you arrange the diode bridge, either for 50/60Hz or 100/120Hz pulses. I really didn't like the rectified sine drive and the LED drive current is given by CdV/dt so it will be half the current at 115VAC.I like Robert Hilsher's circuit arrangment because it is a true zero crossing detector that is quite robust and the RC filter on the Live input helps filter out any noise. The only drawback is the need for a DC supply, however it is 3X improvement in terms of power at 230V.
Low profile (<3mm) board to board connector. - Page 1
Forum section: electronics / projects

author: DTJ
author_rank: Super Contributor
timestamp: March 06, 2018, 09:03:59 am
content: I've got two boards one above the other that I want to run some signals between via a pluggable connector pair.Their mounting is fixed and can't be changed, the space between the boards is 3mm.I've got 8 or so signals that need to got between the boards:SPI x 3 signalsPower 3v @ <100mAGroundA couple of digital status lines.I'd prefer to use 2mm or 2.54mm pitch SIL connectors but the I've only found these Samtec ones with a mated gap of 3.89mm. I need 3mm max.http://au.element14.com/samtec/sl-108-t-10/receptacle-2-54mm-pcb-8way/dp/1668062http://www.farnell.com/datasheets/1927698.pdf?_ga=2.37384996.569325269.1503285096-1413671594.1503025027Have you got a favorite pluggable low profile board interconnect you can suggest?Cheers.

author: Rerouter
author_rank: Super Contributor
timestamp: March 06, 2018, 10:09:28 am
content: Do they have to be vertically mated?If so, look into PCB pin sockets. e.g.https://www.mill-max.com/new_products/detail/2If not, horizontal mating would have less than 3mm gap.

author: ovnr
author_rank: Frequent Contributor
timestamp: March 06, 2018, 10:39:37 am
content: To be honest, pin headers aren't really meant for tight spaces.If 1.27mm pitch is fine, these would work:https://www.digikey.com/product-detail/en/harwin-inc/M50-3130845/952-3587-ND/7044003https://www.digikey.com/product-detail/en/harwin-inc/M50-3630842/952-3611-ND/7044026The receptacle is a bottom-entry model so the excess pin length will be taken up inside the board - you'd put clearance holes for every pin. Total height is 3.0 mm.Otherwise, if having tall components on one (outer) side of the board stack is fine, using bottom-entry connectors (like this2.54mm x8model) means you don't have to worry about anything but the insulation height of the header.

author: ajb
author_rank: Super Contributor
timestamp: March 06, 2018, 03:04:30 pm
content: I'll second the bottom-entry header idea. You can get bottom entry headers in 2.54mm pitch as well if you're more comfortable with that.

author: Neilm
author_rank: Super Contributor
timestamp: March 06, 2018, 07:39:37 pm
content: I have used Molex mezzanine connectors in this sort of application. THey are surface mount connectors that go down less than 3mm

author: DTJ
author_rank: Super Contributor
timestamp: March 07, 2018, 12:07:44 pm
content: @Rerouter - thanks for the Mill-Max link. They look interesting but for my application may be a bit fiddly.I've saved them away for another day.@ovnr (& ajb) - ahhh! That's the solution. Using bottom entry connectors I can do what I want. Thanks very much for the idea. I've found some suitable connectors and are going with it.@Neilm - the Molex Mezzanine look good, a bit pricy for my application but book marked for the future.
Low profile 2.1mm DC power connector - Page 1
Forum section: electronics / projects

author: cowana
author_rank: Frequent Contributor
timestamp: November 28, 2014, 09:37:31 am
content: I'm working on a project that requires a DC power jack. The space is pretty tight, with ~7mm available between the top of the PCB and the inside of the case. This isn't a lot of room, and a standard DC power jack isn't going to fit.I found an ideal solution (pictured below) - a mid mount jack that fits in a cutout in the board. However, just after I found it, the only UK supplier with no MOQ and short lead times sold all their stock and now has a MOQ of 450 units and a lead time of 10 weeks - so it's not really an option.Apparently US Mouser can supply them with no MOQ and a lead time of 4 weeks - but I'd be very wary of designing such a hard-to-find component into a design.Another option is the power jack pictured below, which is just narrow enough to suit my application. My only concern is how easy it would be to plug in - it looks an unusual design. Does anyone have any experience with this sort of jack?The last option is to switch from a 2.1mm barrel jack to something smaller - say 1.3mm (which has a wide range of low profile sockets). However my device is designed with very flexible input circuitry with the idea you can plug it into any old transformer you have lying around - and it seems 2.1mm jacks are most common for power supplies around the 12v area.Does anyone have any thoughts or experience with this area? The 'half exposed' jack looks like it would work, although I'm slightly converned how easy it would be to plug in a connector...Andy

author: krivx
author_rank: Frequent Contributor
timestamp: November 28, 2014, 12:37:04 pm
content: Quote from: wilfred on November 28, 2014, 12:30:14 pmThis sounds like the way to do it unless the current requirements are high. I would go for micro-usb over mini-usb, I believe the micro-usb is rated for much higher number of insertion cycles (the cable wears out instead of the connector).

author: marshallh
author_rank: Unknown
timestamp: November 28, 2014, 06:46:21 pm
content: The open jack designs work fine, but they are designed to line up with a particular hole size in the enclosure. If you can provide that, you're set.
low profile bimetal switch - Page 1
Forum section: electronics / projects

author: generic_username
author_rank: Regular Contributor
timestamp: December 17, 2019, 02:08:50 pm
content: Hello everyoneI'm currently looking for a bimetal switch with a low height.I already found some really promising (and also purchased one) but I'm looking for an alternative.there are basically 5 requirementsheight <= 3mmcurrent max 0.6Ampsvoltage 230V ACcutoff temperature ~30 to 40°Cprice should be affordable ( not like some super mil space wanky doo, made by nude virgins)So I found this little switch alreadyhttps://www.conrad.com/p/tru-components-tb02-bb8d-40-temperature-monitor-0-up-to-125-c-radial-lead-1-breaker-1571466I was really surprised to actually find a switch which met my requirement o.Othis is made by TRU components a sub company from Conrad.Does anyone know for a suitable replacement?cheers
Low profile Ferrite core suggestion - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 01, 2019, 07:24:25 am
content: Hi,I want to design a low profile product, so I need some ferrite core and bobbins to replace EE13 and EE16 transformers, Do we have something with low profile? Ideally if I can find something with 5 or 6mm height max it would be very nice. Also do you know some good and reliable chinese manufacturer to tell?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 01, 2019, 07:29:16 am
content: Tons! Look at any catalog. ELP, planar E and ER, and I forget what others. SMT bobbins (vertical cores with low profile; horizontal cores with low width) are common, or you can make your own from PCB, usually with 4+ layer boards (planar magnetics).Tim

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 01, 2019, 08:20:44 am
content: Thanks Tim for the feedback, do you have a favorite manufacturer or part number? what about chinese manufacturers? do we have a parametric search engine out there? PCB sound nice, but a flyback transformer with about 80 turns of primary!Is it doable?

author: TimNJ
author_rank: Super Contributor
timestamp: April 01, 2019, 05:51:42 pm
content: For a traditional wire-wound transformer, finding an appropriate core/bobbin combination with 5 or 6mm height sounds tricky. 10mm might be a little more realistic. Maybe take a look at EFD15.
Low profile USB camera with narrow field of view? (under 45 degrees) - Page 1
Forum section: electronics / projects

author: monster_of_electronics
author_rank: Contributor
timestamp: February 14, 2016, 09:30:55 am
content: Does anyone know where I can get a reasonably high resolution (3mp+) low profile (not deep/long lens; <10mm~ including lens) USB camera with a field of view narrower than 45 degrees?This is pretty close but the lens is too wide, the fixed lenses I've found seemed to come in narrower focal lengths but they are longer (takes up more space).http://www.aliexpress.com/item/5-megapixel-Ominivision-OV5640-mini-cmos-usb-camera-module-with-45-degree-autofocus-lens-ELP-USB500W02M/32235549464.html?spm=2114.01010208.3.19.SoSkML&ws_ab_test=searchweb201556_9,searchweb201644_1_505_506_503_504_502_10014_10001_10002_10016_10017_10010_10005_10011_10006_10003_10004_10009_10008,searchweb201560_2,searchweb1451318400_-1,searchweb1451318411_6448&btsid=9618a1fc-3126-48d6-9b09-551900348bba
Low quality Chinese potentiometers - so much fail - Page 1
Forum section: electronics / projects

author: setq
author_rank: Frequent Contributor
timestamp: September 30, 2016, 01:16:25 pm
content: Just been the victim of a cheap nasty dual gang no brand Chinese potentiometer. In one small package, we have the following turds:1. Completely non linear even though it's supposed to be linear. I measured both gangs and one is linear and one is nearly log! I'm wondering if this was an assembly error.2. There is a dead spot on both gangs about 10 degrees apart which makes about 10% of the travel completely useless.3. I know the tolerance is 20% but on a 100k one, having one taper that is 118k and another that is 88k takes the piss a bit.4. The thing is covered in grease.This is a new part. I'm wondering what the hell their market is if they are producing these.So in the bin and nice expensive Vishay Spectrol one is on the way.

author: albert22
author_rank: Regular Contributor
timestamp: September 30, 2016, 02:36:25 pm
content: They dont last very long until develop loose contacts. I found them useless.

author: bson
author_rank: Unknown
timestamp: September 30, 2016, 07:44:06 pm
content: A low-end part from a known brand will cost a little more, but still isn't all that expensive, and works a whole lot better. I never buy cheap no-name pots anymore, like you observe they're complete "discard grade" and in the long run it's just a lot of grief and hassle for no savings to speak of. I guess suckers like us is the market for these products.

author: setq
author_rank: Frequent Contributor
timestamp: September 30, 2016, 08:18:42 pm
content: Yep. I powdered it in the garden with a hammer. Feel better now

author: vindoline
author_rank: Unknown
timestamp: October 01, 2016, 09:17:20 pm
content: Quote from: setq on September 30, 2016, 08:18:42 pmOr, as I like to say, "disassembled it with the Irish screwdriver!"

author: setq
author_rank: Frequent Contributor
timestamp: October 02, 2016, 09:18:11 am
content: Haha

author: void_error
author_rank: Frequent Contributor
timestamp: October 02, 2016, 06:43:52 pm
content: Quote from: setq on September 30, 2016, 08:18:42 pmI think the proper term is "Widlarized".

author: dannyf
author_rank: Super Contributor
timestamp: October 02, 2016, 06:51:28 pm
content: Quoteyou have to be rich to buy cheap stuff.

author: David Hess
author_rank: Super Contributor
timestamp: October 02, 2016, 09:28:48 pm
content: Quote from: setq on September 30, 2016, 08:18:42 pmYouwidlarizedit.
low-quiescent current boost converters (1-1.2 volt in, 5 volt out) - Page 1
Forum section: electronics / projects

author: mmagin
author_rank: Frequent Contributor
timestamp: September 06, 2013, 05:21:30 pm
content: I've been looking at boost converters for running some 5 volt circuitry (nothing more than 50 mA when it's in use, microamps in 'sleep' mode) off a single NiMH cell. It looks like there are a lot of choices that are easy to apply:TI TPS61222Linear LTC3525-5Maxim MAX1724EZK50Torex XC9140A501(Edit) Microchip MCP16251 (needs an external voltage divider, that's why I missed it in my initial search)etc...(Fortunately most seem to be easy to hand-solder devices, not leadless or exposed pad)Anyone have experience with these?Aside from taking a careful look at how low the quiescent current draw of these devices is and their efficiency in the desired region of operation, anything to watch out for?

author: mmagin
author_rank: Frequent Contributor
timestamp: September 07, 2013, 08:02:43 pm
content: After some more searching and reading this thread, I think I may just go with the TI part:https://www.eevblog.com/forum/projects/dc-dc-converter-for-small-loads/The Linear part is expensive, I'm unfamiliar with Torex, so it was really close between the TI and Maxim parts, but I'm not really sure the Maxim part would give me significantly better battery life.Looks like I'll be able to live with 3.3 volts actually, which should be better for efficiency.