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Questions tagged [pwm]

Pulse-width modulation, is varying the duty cycle of a rectangle wave, usually with a constant frequency.

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28 views

Voltage drop pulse transformer

I'm trying to design a buck converter controlled by a PWM signal. The PWM signal and the converter is isolated with a pulse transformer. My issue is that the pulse transformer behaves differently ...
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3answers
1k views

Resistors getting hot in this MOSFET driver circuit

I created this circuit as general purpose MOSFET driver circuit for PWM frequency up to 10KHz (usually from microcontrollers): But R3 and R5 are getting hot soon as I connect 5V supply and I did not ...
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28 views

TL5001 buck converter issue

I have constructed the following 12v in - 3.3v out buck converter circuit using a TL5001 PWM controller based on this document. After etching PCBs and soldering surface mount components the board ...
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17 views

STM32F0 input capture and output PWM via the same timer

I'm looking to generate PWM and read a generated frequency via different GPIOs which have the same timer alternative function. Any one knows any existing example from ST or others?
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11 views

How to disconnect ESP32 PWM LEDC peripheral from the GPIO pin

I am controlling many LEDs using ESP32 and just one PWM (LEDC) peripheral. I only need to have one LED dimmed at a time, other LEDs must be off. I correctly control the LED dimming and PWM duty. ...
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1answer
28 views

Center-Aligned PWM when to trigger current measurement STM32F4

I try to implement the Center-Aligned PWM on an STM32F410 and the current measurement triggers from the PWM generation timer. I have some trouble in finding the right measurement point for my currents,...
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37 views

pwm after constant current switching driver

I have searched, but cant find an answer for my specific setup. I have a Xl4015 switching contant current source for my 10w LED set at 1000mA. I would like to add a pwm dimming circuit to switch a ...
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1answer
63 views

Understanding an ultrasonic piezo driver circuit

[Disclaimer: I'm okay-ish with digital electronics, but somewhat a noob with analog stuff. Since this circuit is a) pretty simple and b) still covers both areas, I was hoping that somebody here could ...
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1answer
41 views

4-Pin Fan with PWM dc motor controller(not a fan control unit) [on hold]

Can I use a DC PWM module (not a fan control unit) for a 4-pin fan (directly to 12v and GND)? something like this module wiring will be motor+ to red and motor- to black. does this method shorten the ...
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STM32F407 - how do I run one motor at a time? Why do they ignore delays..?

I'm a newbie. I'm using an STM32F407 discovery board, and I want to control 6 stepper motors using PWM, especially OPM(One Pulse Mode). Till now I've made 3 stepper motors work using Timer 8 (CH1, ...
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1answer
41 views

I need a potentiometer controlled by only a 0-10v signal

I have a PWM control box made for standard 4 pin PC type fans (12v). It has a potentiometer to control the fan speed via PWM. It is powered by its own 12v supply. I would like to exchange this ...
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1answer
64 views

Not getting expected voltage at LED

I recently picked up and arduino nano kit and messed around with all the simple projects. I dont have much EE experience besides those so I have a question that might be pretty basic. I am trying to ...
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57 views

Dealing with coupling of PWM noise into Hall-Sensors as spikes in BLDC driver circuit

I have designed the first revision of a BLDC driver board (based on STM32 and DRV8323 chips). Right out of the bath (after writing the firmware of course) I noticed that the coupling of PWM into the ...
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3answers
728 views

Do I need a heatsink for a MOSFET

I'm currently working on a project where I need to be able to switch 7m of 9W/m LED strip (connected from both sides) using an Arduino with PWM. So the power of the led strip is about 63W at 12V. I ...
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4answers
73 views

PIC PWM and the use of PostScaler

I'm working on a project with an SG90 servomotor, that requires the use of PWM. However the motor works with PWM frequency of 50 Hz (20 ms period), and in my PIC16F690, when I try to calculate a value ...
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34 views

Generate +-12v 1kHz PWM signal from arduino

i’m working on my project.Can someone help me how to generate that signal,i know that arduino can generates PWM signal,but it output will have only 5 V.I think that it need to connect an external ...
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2answers
82 views

How to increase the dimming range of mosfet controlled LED

I'm slowly getting into circuits and I've put together a PWM LED dimmer. The led is driven by this circuit: I'm driving the PWM via a separate BLE device which maps a user input of [0, 100] to an 8 ...
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1answer
31 views

Why does a Solenoid driven with intermittent duty cylce produce higher force than with continuous drive?

I'm selecting some solenoids with my MechE and I noticed something that I didn't have an intuitive explanation for. We were looking at this solenoid and noticed that at the bottom the forces ...
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3answers
139 views

Can I touch voltage?

After watched this man this man, I have some questions. He touched 170 VDC, what is max DC voltage can I touch when I dry? And wet? What is max AC voltage can I touch when I dry? And wet? Is ...
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1answer
22 views

LM2940, 7808 and Multichannel PWM chip

I'm putting together a circuit board to power and dim 5 LED channels. The average voltages on the channels are 12.3V, 11V, 11.4V, 7.8V, 6.6V, and max current is 1A. So my current plan is: 12V ...
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1answer
51 views

PWM duty cycle RPM regulation via sensing DC motor current

I have a DC motor that needs to be RPM regulated, that is, it needs to turn at constant RPM regardless of the load. I've read this can be done by monitoring current thru the motor windings and ...
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1answer
51 views

Constant Current Led Driver (non dimmable) to work with PWM

I have 18W lamps that came with non dimmable led drivers. Ive found datasheet for the main chip (ws3441), which included schematics: and internal block scheme of the chip: I'd like to add dimming ...
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1answer
109 views

How does carrier frequency and pulse width modulation in a VFD work together to control AC motor speed?

There is a lot of online information about this but there is also a lot of contradictory information. What is carrier frequency exactly and does it stay the same or does it vary? I understand the ...
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1answer
145 views

How to flicker high-power LEDs with precise square or sine wave?

I need some advice regarding a setup with high-power LEDs I am currently working on. My aim: I have a set of 6 high power LEDs (http://www.roithner-laser.com/datasheets/led_highsingle/apg2c3-530.pdf) ...
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2answers
360 views

PWM, PAM, PCM sine generation and usage confusion

I am confused about something fundamental regarding PWM, PAM and PCM. I am going to be using a speaker's driver analogy to explain my point. As far as I know motors use PWM for power input, I don't ...
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1answer
54 views

Driver selection for high power LEDs

I'm currently working in a project where I need to control the intensity of 24 high power LEDs in 5 levels. I'm planning to use LumiLeds L1CU-BLU1000000000 (https://www.lumileds.com/uploads/705/PB198-...
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0answers
59 views

Driving WS2812b with STM32 and PWM strange behavior

First of all I want to say that I'm a complete beginner in circuit design but I really want to do one thing. I'b trying to drive WS2812b LED strip using STM32F103 chip. Since WS2812b use 5V and MCU ...
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1answer
58 views

SMPS test circuit PWM controller not switching the MOSFET

Trying my fingers on a very old SMPS circuit (15+ years) section. The open loop test circuit generates 25 kHz pulse train (12 V - 0 V) with 50% duty cycle as designed in the actual SMPS circuit. ...
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1answer
94 views

What should be the PWM Frequency LED dimming in street light luminary

I want to know about the PWM frequency to be applied to PWM driver in street light luminary. Is frequency near 400Hz to 1000Hz OK. What is criteria for the PWM frequency for the street light ...
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3answers
108 views

Using a BLDC motor for regenerative braking

I am planning on using a BLDC motor to drive a small go-kart like vehicle. I would like to implement regenerative braking, but am having trouble finding certain details. My main concern is being able ...
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36 views

PWM generation using Timer in STM32L476

I am a beginner when it comes to working with the STM32. I tried to verify the PWM pulse width and the frequency of a signal on a 70MHz DSO, which is fed by the PWM pin of STM32L4. The Clock input to ...
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1answer
68 views

Controlling 5V DC motor with 9V and PWM

I'm trying to make myself a controllable fan with 5V DC motor. I use 9V battery for supply the motor and PWM Modulator. This is the PWM module that I use. And I'm using this circuit schematic. ...
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1answer
33 views

Multiple lights dimming using single TRIAC zero detcetion module

We know well we can dim single lights using single TRIAC module with the help of PWM signals from controller. My question is, I want to control the lights which are placed on hall. Let us consider 15-...
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69 views

Custom BLDC controller design for prototype Electric vehicle using MC33035 and need of closed loop control in high power EV application

The main objective of my question is to understand fundamentals required to build a BLDC controller and evaluate the design I have worked for months.My controller is divided into a power stage and ...
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1answer
60 views

Dim a LED array through PWM on power supply or output enable?

I have an 8-LED array driven by an 8-channel source driver (TD62783AP) controlled from an 8-bit shift register (74HC4094). When it comes to dimming the LEDs using PWM, I came up with two solutions, ...
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2answers
83 views

Simple Buck/Boost/Other Topologies building tutorials [closed]

For educational reasons, I want to build physical DC-DC converters. I would start with simple buck or boost topology. For start, I wish to have a simple gate-drive for switches, without PWM modulation....
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43 views

High Vds across MOSFET in saturation mode in Flyback converter during simulation

While simulating a flyback converter, I find that even in saturation mode the MOSFET, in spite of having Rds(on) around 0.74 ohms and the Ids = 5.75mA, is dropping almost the entire drain supply input ...
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1answer
66 views

How to switch dummy load circuit on/off with pwm?

I built pretty much the simplest dummy load for testing batteries I found on youtube (EEVBlog #102) , but I modified it little bit. I used 0R1 resistor, because I needed bigger currents from battery (...
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1answer
45 views

N-mosfet low-side switch being turned on with no direct gate drive signal

I made a relay h-bridge by using two 40 amp single pole double throw relays. I used this h-bridge, and another, to each drive a wheel chair motor fused at 20 amps each. I control the direction of ...
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1answer
75 views

PWM nonlinearity

simulate this circuit – Schematic created using CircuitLab I am using the PIC16F1786 in a current transducer to measure 0-1 Amp DC. I use an A/D converter to measure voltage from a Hall Effect ...
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2answers
77 views

Is it possible to generate different PWM Signals for same duty cycles(e.g. 50%)?

Let us expect we have a duty cycle of 50%. Is it possible to reach that duty cycle with different PWM Signals (waveform)? With different I mean variants in the number and lengths of the "active time". ...
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2answers
51 views

Can a MOSFET generated high voltage (315v) pulse train be measured using a DMM in AC mode?

I am using a 5V pulse train generated from a UC3845 PWM controller to trigger a MOSFET (K2645) which is biased with 317VDC in series with Rd= 120ohms, Rs=20ohms and primary of the PWM transformer. I ...
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2answers
454 views

ATtiny13A - Can't generate software PWM with CTC mode

I'm trying to make a remote control RGB LED light using an ATtiny13A. I know the ATtiny85 is better suited for this purpose, and I know I might not eventually be able to fit the whole code, but for ...
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1answer
61 views

Control LED strip with MOSFET and PWM Arduino

I want to control the brightness of my LED strip. In this way, I'm thinking about using a MOSFET N-channel. Can you see what I conceive below : I want to manage the Id current by shifting the Vg ...
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1answer
32 views

What are the implications on vibration measurement from decreasing Pulse-Width Modulation (PWM) frequency of a 9V electric motor?

What is the effect of a PWM (or other duty-cycle variation method) frequency change on the vibration of an electrical motor (9V, DC)? I plan to measure the (surface-) vibration with acceleration ...
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43 views

Changing PWMs parameters on STM32 board

I am trying to change the values of Prescaler, Autoreload and Pulse of PWM using Serial communication on a stm32 Nucleo-F091RC. For the most part I am able to do so since the below code works fine: ...
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2answers
70 views

How to regulate PWM to control a boost converter

I am creating a simple boost converter following the classic circuit diagram just for learning purpose. The switch is a power transistor controlled by PWM output of an Arduino (with additional ...
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2answers
24 views

TL494 minimum operating voltage VCC

Has anyone operated TL494 on +5VDC practically as it works in simulation software ? minimum operating voltage indicated in datasheet is +7VDC . please confirm.
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1answer
63 views

What PWM Frequency should be used for a 12V DC Gear motor?

I have this 12V DC Gear motor, but I can't find much info about it online. The reason I have bought it was that I found this particular motor across several tutorials on how to build an RC car. I ...
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2answers
85 views

16A Relay controlled with PWM

I am not very experienced with relays but I need to control the state of a relay with a PWM signal such that if the microcontroller is damaged and the controlling pin gets stuck in a high or low state ...