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

learn more… | top users | synonyms

1
vote
3answers
49 views

Generating a PWM ramp signal using logic gates

I have a microcontroller outputting a ramp signal on an I/O pin in PWM form. i.e. the duty cycle steadily increases from 0% to 100%, then drops to zero and repeats. After smoothing I end up with a ...
1
vote
1answer
43 views

Problems with using 20Mhz crystal withPIC18f2420

I am using PIC18f2420 to generate PWM. I am using Timer 2 with 4MHZ crystal, which works perfectly by giving me PWM. I need to get 100KHZ of frequency for PWM, for which, 4MHZ crystal is not enough as ...
0
votes
0answers
17 views

Voltage-mode or Current-mode PWM controller?

I am trying to decide between a voltage-mode and current-mode PWM generator to connect to a gate driver IC to drive my power MOSFET. The PWM will be generated based on a current input to the ...
0
votes
0answers
15 views

Current-controlled PWM Generator with variable duty cycle?

I need to implement a variable duty cycle PWM generator with constant frequency (100kHz) to help drive a MOSFET. Is there such a thing out there in the market or is it something I need to build with ...
0
votes
1answer
32 views

Drive 12V load with 5V PWM

I want to control a 12V heater coil with 5KHz 5V PWM using the below circuit, but the load voltage does not goes higher than 5V. I made a similar circuit with a MOSFET and the result does not changed. ...
0
votes
1answer
26 views

Boost PWM Signal to 12 V LED strip?

A little background: I'm hoping to take the PWM from the Disney Parks Made with Magic Ears in order to drive a short 12V strip of LEDs (Here's a teardown.) After taking a pair apart and testing, I ...
1
vote
1answer
26 views

What voltage reference is the pwm signal using in the QUADRUPLE HALF-H DRIVER SN754410NE?

I have a QUADRUPLE HALF-H DRIVER SN754410NE, and i saw online that the 5V from the arduino goes to pin1, pin 9 and pine 16 and on pin 8 you attach a separate 5v supply that has at least or more than ...
0
votes
2answers
49 views

RPM of two 300rpm motors is not equal, what to do?

I have two 300 RPM motors. But one moves slightly slower. Hence the robot does not move exactly straight. I tested various PWM values and now I am getting very less angle of turn. i there any other ...
0
votes
1answer
16 views

Controlling an ESC for Brushless Motors with an RPi

Originally posted on Robotics, but guess it's not active enough. I'm looking to build a new (first) quadcopter without the conventional flight controller and radio, with an onboard RPi and applying ...
0
votes
1answer
66 views

What happens when you rectify phase cut current?

Forgive the simplicity of the question, since I'm not a professional, just a tinker with a soldering iron. Just dancing with the idea in my head, I believe that if I rectify a current that's been ...
0
votes
1answer
18 views

STM32F051R8: PWM timers don't work?

I'm working with MB1034B discovery board and STM32F051R8 microprocessor. I'm trying to output some PWM pulses using hardware timers. I use this tutorial (for STM32F4xx): ...
4
votes
1answer
74 views

Grounding an Opto-isolated Microcontroller

First off - thank you all so much for all you have done for me, and the hobbyists all around the world. I love you all and truly appreciate what you do for the field of hobby-ism. The AC in this ...
0
votes
1answer
33 views

Analog controlled H-Bridge to digitally controlled?

I am using this circuit to control a motor. Initially I was using 12V PWM generated from a 555 astable circuit. I am now trying to make the circuit controllable via an 8051 Microcontroller The ...
1
vote
2answers
35 views

pic18f2420 pwm frequency

I am generating PWM using timer 2 of PIC18f2420. I have 4MHz external clock crystal. The maximum frequency I can get from the PWM is 3.9KHZ with 1:1prescaler and postscaler. I need to get 100KHZ, any ...
0
votes
2answers
44 views

PWM + LC filter - voltage value non linear with duty cycle

I'm experimenting with PWM and LC filter and I think it works correctly when it comes to smoothing signal, but for some reason voltage on the output is not linear with duty cycle. I use 56uH inductor ...
0
votes
0answers
38 views

MAX PWM of MSP430G2553 or any MC

I am playing with microcontrolers lately, more specifically MSP430G2553 with the LanchPad. I want to output a PWM and also read a PWM. For producing PWM I use a timer that calls an interrupt. For ...
0
votes
3answers
59 views

H-Bridge with 1 PWM and 1 Output

I'm looking for a solution to control the direction of a powerful DC Motor. I came up with the idea to use a H-Bridge. Since the motor uses up to 3.2A the amount of possible H-Bridges is quite ...
0
votes
1answer
44 views

Using PSMC instead of CCP

Hi I am building a motor controller and I decided to use PSMC instead of CCP to create my PWM, my decision was based on the fact that I dont have enough CCP ports on my pic 16f1788 for the project. I ...
1
vote
1answer
65 views

current control via microcontroller

I have a micro-controller which calculates and decides about the current each minute. Then for one minute the circuit must hold that current constant. Then it should control the current via a buck ...
-1
votes
1answer
31 views

PWM generation with AVR

What is the best way to generate 5 PWM signals in range of 10 KHz with AVR ATMega16? I am thinking about a few possibilities: 1- Does AVR generate any PWM signal automatically on any of it ports? (I ...
0
votes
0answers
33 views

DC Motor Speed Control With 555

Can you please explain why this circut is not working in simulation. I get GMIN Stepping failed, too many iterations errors. Is there something wrong with the design?
1
vote
2answers
56 views

EMC considerations for driving a solenoid via PWM over a long cable

We're designing a circuit which essentially has the topology shown below. We're driving an inductive load (24V, 3.8Ohm solenoid - max avg current = 2A, but peak current can be 6.3A) using PWM. ...
0
votes
0answers
29 views

PWM output in synchronization with the frequency of input

i want to create an electronic circuit to replicate the analog input in terms RMS waveform, frequency and polarity , by using LM555 (no microcontroller) realize PWM output in synchronization with the ...
1
vote
1answer
36 views

AVR Attiy45 PWM Servo motor control in Assembly

I'm trying to contol a servo motor with attiny45 writing the code in assembler. I figured out how to set the timer in pwm mode and how to choose a needed prescaler. And with different OCR0A values i'm ...
1
vote
0answers
20 views

Design of PWM controller for Wound Rotor Induction Motor

I want to make a controller for Wound Rotor Induction Motor in which effective external resistance on rotor side is varied by changing the duty cycle(PWM controller) with the help of a chopper.What ...
0
votes
2answers
76 views

Can I adjust the volume of a DAC using PWM?

Here is a circuit that allegedly converts PWM into a precision voltage reference: I am thinking about feeding that reference into the reference line on this MCP4921 DAC. My goal is to generate ...
0
votes
2answers
126 views

Generating 12V PWM from 5V PWM

I am generating a 5V PWM signal from my MCU (an Atmel ATMEGA1284P). I need to convert this to a 12V PWM signal. For this I designed the circuit below, something very similar to a Sziklai pair, but ...
0
votes
0answers
17 views

lmd18245 dc motor driver

How to build dc motor driver lmd18245t. wanna control dc motor with arduino uno by pwm signal so how make driver circuit using lmd18245t ic and in pic. i made circuit schematic is this correct or any ...
0
votes
0answers
77 views

What is the type of this IC?

This is the internal structure of an IC. The only information that I have is the use to control the temperature of soldering iron via a triac. Pinout also is missed. Fist thought is the TL494 but ...
0
votes
1answer
61 views

Simplest method to filter a PWM'ed sinusoid?

I am using PWM to dim a bulb and was wondering how I could restore the chopped waveform to a sinusoid whose amplitude varies with the duty cycle. The switching frequency is 25Khz and the line ...
0
votes
3answers
48 views

Two voltage sources - selecting with digital signal

I'm trying to build a fan controller based on Arduino. It will be (at least I hope so) possible to either control with pure PWM or voltage regulator based on buck converter. Now what I'm trying to do ...
1
vote
1answer
55 views

PWM LED using TIM1 on STM32

I need to PWM my LED on STM32F3 Discovery which is on PE8. I have found code which is using PWM on PA8 and PC8 (one using TIM1) but unfortunately I can't change it to PE8. How to do it? Or maybe you ...
0
votes
3answers
102 views

Whats the reason for triangular carrier PWM

I understand that triangular carrier PWM uses a higher frequency triangular carrier wave to compare with the desired output waveform but I would like to know more about the process. I've also learned ...
-1
votes
1answer
58 views

voltage dropping when connect pwm output pin of a microcontroller to resistor

I have a circuit that measures the distance to the obstacle then i convert this value to voltage with PWM method . So far everything working properly but voltage dropping when connect pwm output pin ...
-1
votes
1answer
51 views

STM32F205 - can i use a timer to generate a low pulse of specified length

I want a pin to be high by default and then generate two 125-250 µs pulses with 0.1 µs resolution using a command. I was thinking about using TIM1 in one-pulse mode but I don't see a way to invert the ...
0
votes
0answers
57 views

Reverse engineering MOSFET power circuit

I'm looking at a portable heater circuit that uses a 1.4 Ohm resistive load as the heating element. The circuit in question uses an N-channel dual output mosfet, and on the other side of the board a ...
-1
votes
0answers
22 views

how can i generate a truncated ramp signal from my pwm signal in labview

i have used the integretor at the output of my pwm signal to make a ramp but the ramp is not truncated.it continuously integratig from its pevios integrated value.how to start the integration from the ...
0
votes
1answer
71 views

How do I troubleshoot this high-frequency PWM fan control circuit?

I have a 230 Volts fan from EBM papst. It is a fan that can be controlled through a PWM signal (between 1 and 10 kHz). I have built the circuit that is in the manual (see image) I did get this ...
1
vote
1answer
52 views

Atmega328 fast PWM (mode 15) on timer 1 not working

I cannot get PWM to work using mode 15 (a fast PWM) of timer 1. It's always giving me a high value of around 4.5V on PORTB2. ...
1
vote
2answers
102 views

How to modify a pulse with a very narrow on duty time to a squarewave like pulse?

I have the pulse as seen above. I need to convert this to a pulse without affecting its frequency but modifying its on time. It gives problem when sampling it for some reason, so I need to convert ...
0
votes
1answer
79 views

PWM or Phase Control Dimming?

I want to dim a lamp around 70W or more using arduino. I have found two ways for doing that. The first one is to make a circuit that "cuts" the sine wave and produce the dimming effect (link). The ...
3
votes
3answers
340 views

Control Power Resistor with MOSFET

I am making a temperature control system using an Arduino. However, I have a problem with controlling a power resistor (which is used as a heater). I was suggested to use a MOSFET to control it. ...
0
votes
1answer
82 views

PWM driven bipolar DC motor controller filtered with LC for a peltier element

I want to control peltier element's temperature with a PWM driven bipolar DC motor controller to be able to switch between heating and cooling and also control the level of it. The peltier element is ...
0
votes
1answer
50 views

PWM Control of Hotwire Power Supply

I'm building a hot wire setup to do various hobby projects. I've got most of it figured out already, thanks to the wealth of information there is out there. I have a 12V switching power supply with a ...
1
vote
2answers
111 views

Can i use a PWM HHO Controller to control Brushless DC Motor?

Hi im a electronics newbie. The part im talking about is DC 10-50v 12V 24V 48V 3000W 60A amps DC Motor Speed Control PWM HHO Controller here is the link My ...
0
votes
2answers
77 views

3 channel 10+bit PWM

I am building a controller for RGB LED strip (12V 5m 5050 LED RGB strip with common anode). My current solution uses Arduino Uno with 3x IRFZ44N MOSFETs to power the strip. The solution is partially ...
0
votes
1answer
25 views

PWM Return Problem

A controller send pwm signal with 2 wires 1- PWM 2- PWM Return But servo motor has 1 input pin. So is it correct to use servo supply return (28v Gnd)or servo chassis input for controller pwm return ...
0
votes
3answers
195 views

Why do I need I large resistor to the GATE of my MOSFET?

I tried to control the brightness of a LED using a Linear Hall Effect Sensor fed to an Arduino, and PWM output to the gate of a MOSFET connected to a 12V battery. The LED was flickering a lot, and ...
0
votes
2answers
80 views

Does frequency equal the number of steps a stepper motor will do?

http://www.thorlabs.us/thorcat/ETN/ZFS13B-Manual.pdf I am supplying a driving PWM signal to this stepper motor. However, I want to specify exactly how many steps to take with this motor. Does the ...
0
votes
1answer
337 views

Removing ripples from PWM controlled LED in camera vision application

I have made a camera vision setup with highpower LED's which are controlled with a simple NE555 timer and a mosfet. The LED system is lighting up an area where a camera is looking, but unfortunately i ...