Questions tagged [pwm]

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

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Why is the duty cycle much wider than it should be? PIC32MZ & PWM

I'm working with the PIC32MZ2048EFM100 and XC32. I'm using some outputs as PWM signal generators. There are frequencies for which the pwm works fine, but not for others. For example to get 24.4 kHz, I ...
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Duty cycle calculation

I am trying to solve a numerical where the Speed of a DC motor operating at 15V was measured to be 2000 rad/sec. Now a PWM signal is applied to the same motor to get a speed of 400 rad/sec. If the ...
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Circuit of a PWM DC motor speed controller for a 12V 10A DC motor

I saw many circuits for this, most of them were using 555 IC, I wanna use a 12V 15A switching power supply for this motor, so I need a high current PWM speed controller but I don't know how to design ...
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68 views

Exponential ramp for PWM

I'm planning an exp-ramp generator with the following characteristics: Implemented on the PIC16F1773, an 8-bit device running on HFINTOSC PLL of 32 MHz. It has somewhat complex capture/compare/PWM ...
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69 views

How to choose PWM frequency?

I got an article on this link. In this article the author chooses a PWM frequency of 31,372 Hz to get a smooth signal. How do these frequency values get a smooth signal? I've read other articles on ...
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747 views

Fan does not spin when controlled by PWM

I am using the following fan : ME70201V1-000U-A99, which should be supplied at 12 V and consumes about 150 mA. My schematics is as follows : Than fan is connected to X3. PWM_VENTILO is the PWM output ...
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53 views

Help designing a circuit working with PWM and polarity swapping

Hi all I'm after some advise for a circuit I'm trying to design. I have an existing circuit that drives two low power bulbs. This is my signal circuit and runs on 12v, has a switched negative and uses ...
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1answer
136 views

How can I fix this LED dimmer circuit?

simulate this circuit – Schematic created using CircuitLab The circuit reverse-engineered above is a LED dimmer which is driven by 555 timer in astable mode which then drives an op-amp to ...
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45 views

Modify the output voltage on a PWM controller to fall within LED driver range

I'm trying to use a simple PWM controller (this) as a dimmer for a Meanwell LED driver (this). The driver accepts PWM dimming but needs a voltage range of ~2-8V, and the PWM controller outputs 7-12V ...
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63 views

Is it possible to use a MAX232 to convert 0 to 5V PWM to 0 to 12V PWM to input to a motor driver requiring 0 to 12V PWM logic?

I'd like to drive a 16kHz PWM signal at 0.5mA into the input of a motor driver expecting logic levels of 0V for LOW and 12V for HIGH, and expecting a PWM signal around this frequency. The PWM signal ...
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49 views

PWM-modules operating simultaneously on different frequencies

I am using a PIC16F15345 which has 4 10-bit PWM modules. In order to minimize electromagnetic interference I tried to use the PWM-modules on different frequencies working simultaneously, but it did ...
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how to write plc code for PWM to run a dc motor on CP1L

so im actually new to plc and i got a project in that . what i want to know is how to get the programme for PWM IN OMRON CP1L to run a dc motor. i dont actually know plc programming so requesting if ...
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Making a variable DC power supply [closed]

I have a treadmill 90V DC motor I am trying to install on my lathe. I bought a rectifier and a 90V-6V pulse width modifier. It had 105 DC volts going to the modifier. I hooked it up and instantly ...
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42 views

PWM square wave to DC voltage simple conversion

How do I convert a PWM square signal into a stable DC voltage (0V - 3.3V) in easiest and reliable way possible? (preferably in programming- microcontroller)
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AC PWM noise generator design advice

I already tried to solve my LTspice problems within another thread here on the forum but I guess my design is bad. So for this reason I decided to start a new thread with some more information about ...
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Solution for EMI on signals in a connector?

I have PWM signal and PSU signals coming from switch mode PSU to our machine. The motor drive boards that run the stepper motors in the machine are located in the PSU. At the moment the outputs to ...
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Why can't I have a PWM signal with 5V in the PCA9685 PWM driver?

I've got a BLDC motor which I can control with a PWM signal ranging from 0V to 5V. So I use the PCA9685 PWM driver to create a signal. The PCA9685 product page at Adafruit says this about the output ...
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68 views

High side MOSFET extremely hot in a half bridge circuit

The high side MOSFET becomes extremely hot when I try to run the half bridge, and the output does not seem right. The PWM signals to Hin and Lin come from an Arduino - 47.5% duty cycle, dead time of ...
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28 views

Reading 14V PWM signal on Attiny85

I want to read the 14V PWM signal on Attiny85 running an Arduino IDE. It is a control signal sent from the car's PCM to the cooling fan. The frequency of thes signal is 120Hz while the duty cycle is ...
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67 views

Simulation of SVM PWM

I have developed a simulation of the space vector modulation (svm) for standard two level three phase voltage source inverter. The simulation is created in the Scilab/Xcos with usage of C block (i.e. ...
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53 views

PWM output vs Digital output

Could I use a PWM output as a digital output? For example to act like an on-off signal by varying the duty cycle between 0 and 100%. Does it involve any difference in power consumption?
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77 views

Is over-voltaging a DC fan, and then reducing speed with PWM a bad idea?

I have an 18V system and I need to run some fans off of the 18V rail. I've been using 24V fans with PWM control and they work fine (although are slower than their fully rated 24V speed). Now we can'...
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29 views

What are some ways I can modulate the duty cycle of SPWM with mixed signals?

I'd like to experiment with SPWM, as used in motor control applications. But instead of modulating the duty cycle with a single frequency, I'd like to use a mix of frequencies. I've been searching for ...
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49 views

Correct version of PWM speed control of BLDC

Different sources shows different versions of speed control: https://youtu.be/b5J5qkR7msc?t=418 In upper source output (duty cycle) from PI controller (that takes as input difference between desired ...
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What is the relationship between the PWM duty cycle input and the angular displacement and RPM of a DC motor?

If possible, could someone point me to some resources explaining these relationships? It would also be helpful if the resource discusses non-linearities such as dead-zones in terms PWM duty cycle vs. ...
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DRV8871 (DC-Motor Driver) extremely reduced output voltage

I am working on a PCB which contains a PCA9685 PWM Driver and four DRV8871 motor drivers. The basic idea of the board is the PCA is controlled by a micro via I2C which then creates a PWM signal sent ...
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45 views

AVR setting certain PWM frequency and duty cycle is not working right

I am prototyping a simple LED dimmer on an Arduino Uno (Atmega328p) and I have issues with the PWM frequency and duty cycle I am trying to adjust. To get a frequency of 200Hz flat I am using the CTC ...
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63 views

PWM speed control

I would like to create simulation of speed control of BLDC motor (something based on following scheme): But I have a problem with understanding how to compute duty cycle in Controller block (that is ...
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114 views

Help finding PWM IC with marking on device 'FA=606'. Package of device is SOT23 - 6

I found this 6 pin PWM IC in one of the SMPS. I am unable to find any of its details on Google. I am requesting if anyone could help me finding the device name. The marking is something like FA=606 or ...
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105 views

Can 66% DC 5V PWM signal damage 3V rated components

Hopefully a simple question here, but I have a 3V motor that I was hoping to control with a 5V PWM, which got me to thinking more about how PWM averages out a signal to give a lower voltage, ...
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STM32 PWM Setup - Bare Metal in CubeIDE

I have an STM32L476 Discovery Board. I'm trying to generate a PWM signal on the GPIO pin PE14 using TIM1_CH4 using bare-metal in CubeIDE. I have created a new project in Cube and have kept the default ...
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66 views

PWM FAN Control signal comparison

I am working on a cooler controller board. I am using 4 wire fans (12V, GND, HALL, CONTROL), I am using a simple 555 timer circuit to control the speed of the fans. However it would be nice to display ...
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What is time constant for this UC3845 circuit?

Time constant tau=R*C=100 (us) Am I right?? How to get relation equation about V_ref and V_c? me: Am I right?
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84 views

DC/DC Switching Converters: Is it possible to run a current-mode converter in voltage-mode only?

DC/DC Switching Converters: Is it possible to run a current-mode converter in voltage-mode only? If so, is there an example using a buck converter? In particular, I'd like to use UC3843 (LT1243) in ...
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PWM Analog DAC using MCU

I have attempted to use a calculator without success. Using a 5 V logic gate that will be driven by a Kinetis MCU, I would like to make a DAC. I have tried a 10k and 100nF filter but at 1 kHz I get a ...
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52 views

What exactly does Close Loop Speed Control System control?

I'm working on a project about controlling Brush-less DC Motor using PI(Proportional Integral) Close Loop Speed Control Method. 3 Phases Motor is driven by 6 MOSFETs, Rotor speed is sensed and ...
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STM32 - Configure Output Compare Registers on the Fly

since this is my first, feel free to give newbie a feedback :) I have a following setup with my STM32 Nucleo (simplified, ignore the HW behind): a) one input signal acquisition (Square wave, consider ...
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Failed to use a low pass filter in order to convert PWM input to digital output

I want to convert a servo control signal to a digital 5V or 0V output. This is the format of my PWM signal: The different thing is my input pulse width will be either 1ms (minimum) or 2ms (maximum.) ...
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157 views

PWM LED driving issue

I'm driving 6 serial-5 branch LED strips with PWM driver. Each branch has 90R resistance. OSRAM GW JCLPS2.EM 6500K LEDs are used in the strips. simulate this circuit – Schematic created using ...
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Finding a I/O expander that supports 18 PWM outputs or another solution for MOSFET control

I am a student working on a university project. I need help figuring out how I can supply 18 PWM signals to 18 gate drivers, in a 3-phase inverter. The inverter is built up of 3 half bridges, with 6 ...
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84 views

Noise on the PWM signal. What value of capacitor should i add to decrease the noise?

I have noise on my 60Hz PWM output. The PWM output is going to the ESC to control the motor. Below is the signal with 5V per division. The PWM signal is a 60Hz, 10V signal. The duty cycle can be ...
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EFM32ZG110F32 Timer PWM with DMA - slow to update

I have a project where I am trying to drive some Addressable RGB LEDs which require a high-frequency PWM signal (800kHz) with a duty cycle of either 33% or 67%. I have started from the following ...
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1answer
38 views

PWM of 2.8v LED input (high-side driver IC selection)

I'm trying to control brightness of some commercially obtained instrument panels (for a mock aircraft cockpit). The panels have some internal LED strings (presumably, anyway) which are explicitly ...
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636 views

MOSFETs on Motor Controller died

I've received a prototype for this PCB I described in a different thread: First PCB design, PWM Motor Controller feedback I've changed the design based on the feedback I got there, I changed the gate ...
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WS2812B strip glitches or flickers. What's the cause?

I've rebuilt the Project Piano LED Visualizer but I'm experiencing some issues with the LED strip that I don't understand. I'm using a 10A/5V power supply to power a strip of precisely 180 WS2812B ...
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Is there any CC Led Driver IC that has common GND between led cathode and VIN-?

I have a project that has as 3W (using 500mA) Led and an I2C sensor at the end of a cable, and I need 6 wires for it. (4 to the I2C sensor) and 2 for the led. I’m using the PT4115 CC led driver CI, ...
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164 views

Will this shottky diode circuit protect my ADC, and if so, are there options with more than 2x channels?

I am trying to read 8x 12VDC digital inputs and 4x 5VDC analog inputs with my 3v3 Teensy 4.0 Microcontroller. In V1 of my design, I used a voltage divider circuit to drop down to 3v3. I would like to ...
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56 views

How to prevent accidental load grounding in N MOSFET low side switching?

I have a low duty logic level from a MCU driving a N MOSFET to give a 100ohm load 50V 5% PWM (common source, low side switching). The load needs transient high current to work, but cannot withstand ...
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1answer
45 views

How can you generate a PFM signal for an LLC converter?

I am researching resonant DC/DC converters that use PFM (Pulse Frequency Modulation). Before that, I was only familiar with PWM modulation, which I could generate at a given frequency from an Arduino ...
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139 views

First PCB design, PWM Motor Controller feedback

EasyEDA Project I made my first PCB design and I would like to hear a quick feedback to it. It is a motor controller board, with two MOSFETs parallel, driven by a MOS driver IC and the PWM signal ...

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