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

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34 views

How to switch between two serial data or PWM lines with an Arduino

I am just wondering how is it possible to "switch between" two different serial data or analogue signals using an Arduino. Can I use two transistors to switch between two different PWM or Serial ...
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1answer
35 views

PID control using halogen dimming?

I am looking for some enlightenment with regards to a project i am working on. I aim to use a halogen bulb as a heating element to implement PID control. I intended to dim the halogen bulb (using ...
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47 views

Design considerations for internal PC parts

I'm designing a PWM fan controller. It will be interally mounted inside a PC and will take power from the normal 4 pin Mate-N-Lock ("molex") connector. The on-board MCU and LCD will draw power from ...
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0answers
14 views

Problem with Constant Off-time PWM/Variable Frequency on dsPIC30F2020

I'm using the Microchip dsPIC30F2020. I've been trying for the longest time to get some sort of PFM signal for my project. I see in Section 12.4.7 there is the ability to have constant off-time PWM ...
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1answer
22 views

Torque control with H-Bridge via direction pin

Using the LMD18200 (H-Bridge) and the LM3524D (PWM regulator) I should design a torque regulation. I've found a circuit in the LMD18200 datasheet which uses the current feedback to adjust the PWM. ...
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4answers
195 views
+50

MOSFET PWM switch jamming on - why?

The circuit presented here is sized to switch 100W at a minimum pulse width matching 250Hz. But actually it's currently only being asked to switch around 10-20W. The load is an array of LEDs. Q1 ...
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27 views

Using 3 Channel Video Switcher Module with Arduino

Hey all I am wondering how to go about switch from camera 1, 2 or 3 using this 3 Channel Video Switcher Module on ebay here. Since there's only V+, V- and signal for the "switch" it looks to take a ...
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2answers
46 views

Can you set the PWM output of an Atmel AVR to a specific frequency and have control over duty cycle?

I'm trying to drive an LED at 38kHz with a low duty cycle like 10% from an Atmel ATTiny88. The chip is currently running at 8MHz, but could be adjusted for this portion of code, if need be. Using ...
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1answer
41 views

How to calculate frequency for PWM design

I would like to create a PWM controller for an open loop galvo-mirror. The similar questions involve motors and I can not directly use that approach to galvo-mirror which only deflects, not rotates. ...
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1answer
56 views

Is there a difference between 100% duty cycle PWM and continuous current?

I was thinking that 100% duty cycle PWM always keeps output HIGH ( just like a continuous current ) but according to Proteus simulation the output still falls and rises in a very little time Is that ...
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1answer
74 views

Increase toggling speed of PNP for PWM

I got a shift register which I use to PWM LEDs. Since I multiplex this toggling I noticed some "afterglowing" if the next LED is not active of the same color. (RGB cathode) Multiplexing by the MOSFET ...
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31 views

can I drive 100 or so LRAs with WS2811 controlling DRV2603?

I would like to make a suit with 100 or more individually controllable Linear Resonant Actuators. Texas Instruments makes this http://www.ti.com/lit/ds/symlink/drv2603.pdf which take a PWM as an input ...
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1answer
94 views

PIC - 4-20mA (Duty cycle formula)

I am implementing a 4-20mA current loop to my PIC. I have everything working. I am measuring the distance away from an object. When I hardcoded the distance as 300 the output voltage is 4V and when ...
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1answer
48 views

Beaglebone Black PWM Driver for 12VDC 1.05A Motor | Drive from Positive Side

I have several 12VDC 1.05A pumps I am using in my hombrew system which I would like to drive via PWM on my BBB. Each one will have a hall effect flowmeter attached so that I can get flowrates, totals, ...
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7 views

16 bit PWM on a mega [migrated]

I have two Arduinos, a nano and a mega. I want to output 16 bit PWM, but can seem to only get it working on the nano. I'm adapting the code from this website: ...
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0answers
39 views

PWM for my air-compressor 15 Amp dc-motor

I have read some similar questions but didn't get the answer for mine. I want to make a viair 12v compressor run at a low pace to fill some tires very slowly drawing as few amps as possible. Could I ...
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1answer
49 views

Current usage with multiple PWM controlled motors

I have a circuit that can use 25 A of current max, it is on a 25 A fuse. I am looking to control 4 DC brushless motors using ESC's. The trouble is that the motors are rated at 7A max current. I know ...
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1answer
102 views

Transistor amplifier circuit for triangular wave

I've made triangular wave oscilator as shown in Fig. 1 and it works perfectly at frequancy 10 kHz with peak voltage +3 Volt to -3 Volt. I intend to generate SPWM. But when I feed this circuit to ...
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55 views

PWM from 1v to 5V convert to 12V

guys thanks for time and help... i need to convert the signal of pwm output the pwm signal cand delivery from 1v to 5v i need to read this signal and boost to 12V for on/off relay where i can find ...
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2answers
33 views

Inverted PWM with ATTiny10

On a 10MHz ATTiny10, the following code generates the same 40kHz 50% duty PWM on both pins 0 and 1: ...
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3answers
57 views

HEXFET PWM motor driver does not work

I'm trying to drive a motor for an academic project, using the circuit in the image. The STM32F4 Discovery board that I'm using in this phase of the project produces a 30Khz PWM at 3V, that is correct ...
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52 views

PWM and brushed DC motor - AC input? Limiting RPM?

I'm looking to replace the 20-year old poorly-performing speed control in a MIG welder. It allows the user to adjust the speed of a small brushed DC motor, which drives thin welding wire of of a ...
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3answers
82 views

Detect a missing PWM signal in the smallest possible board space

I have a motor control board that basically has zero space left, and the customer wants to add a fault flag to tell if their 2 kHz PWM input signal is lost. So basically, I need to detect a lack of ...
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1answer
36 views

Voltage wave form across a DC motor driven by a transistor with pwm

Above is the simple implementation for a DC motor control with pwm. I was expecting to see a square wave with a Vmax when Q1 is ON and zero when Q1 is OFF like the one here: standard pwm But ...
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1answer
45 views

How does this motor drive circuit work?

The Drive terminals are connected to a PWM signal generated by an arduino micro controller. The purpose of this circuit is to isolate the arduino from the motors to avoid too much current being drawn. ...
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70 views

STM32 - Multiple channel PWM input

I am using an STM32F405 based board , (OpenPilot revo ) to receive PWM signals from a joystick receiver . i have to xapture 5 PWM signals using only two timers , the timer 8 and the timer 12 . I've ...
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2answers
163 views

Convert positive square wave to positive-negative

I am looking for a way to convert a square wave coming from a microcontroller with voltage range from 0V to 5V, to a voltage range from -12V to +12V. The frequency of a square wave will vary from few ...
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3answers
66 views

How to up-convert PWM frequency without using a microcontroller?

I am trying to drive a motor H-bridge, but my control system can only support a 400 Hz PWM signal (black box, can't change it) which gives the motor an extremely loud 400 Hz whine as you would expect. ...
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1answer
88 views

Temperature stabilization with PWM , PID controller with delay system

I am doing a project to control the temperature with PWM. I use peltier, thermistor,mcu and h-bridge mosfet. I want to reach a temperature with an error less than 0.05 and stay at that temperature ...
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2answers
50 views

DC - DC Amplifier for Piezo Buzzer

I have a Raspberry Pi outputting a 3.3v DC square wave that I'd like to be able to amplify to just under 20v, the maximum the piezo can handle. Just to clarify, the piezo does not have an internal ...
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0answers
29 views

Pulse frequency for a pulse width modulation application

How can I determine the pulse frequency for a DC motor speed control or an LED brightness control. I have no data about the DC motor and led frequency dependence they both do not provide anything ...
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2answers
67 views

Basic h-bridge motor driver circuit for audio PWM waves with possible negative voltage

I need to control a DC motor with the PWM audio waves coming out of the audio jack of a device. The device will send a positive PWM to drive the motor forward and a negative PWM signal for driving it ...
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1answer
81 views

What is PWM Dead Band and when should I use it?

I'm having trouble understanding this concept, here is what the documentation in my microcontroller says about it: dead bands are defined as the number of PWM clock ticks from the rising or ...
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1answer
60 views

Mosfet life expectancy?

How to determine the life expectancy for the given mosfet? Mosfet : IRFP460 Mosfet Datasheet http://www.vishay.com/docs/91237/91237.pdf Actual Voltage,Current and other specification. Vds = 180VDc ...
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1answer
36 views

What is the name of the IC that runs a low-harmonic power supply?

I'm interested in building an AC/DC converter for low-harmonic applications. Single-phase AC input, followed by a rectifier and a PWM-controlled boost converter. I know there are ICs which are ...
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2answers
85 views

How to find duty ratio of a PWM using input capture?

I have a controller PIC18F and it supports input capture peripheral. I understand it can be used to find the frequency of the incoming signal. How can the duty ratio of PWM can be obtained from the ...
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1answer
53 views

Analog PWM generator from 0%

I have to prepare easy analog PWM regulator which can operate from 0% (0V). I know that one 555 can't do that... Do you know any circuit that can handle that?
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1answer
80 views

One PWM timer to two outputs?

first post here, so sorry for any bad styling. I'm working on a group project and using an Atmega328, without going into specifics, I need to drive two fans, two servos, and 1 CTC based function from ...
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1answer
86 views

Generate PWM signal based on 555 for Meanwell LDD driver

I am using a Meanwell Led Driver LDD-1000H. It has a single pin for PWM input for dimming. I have seen many sketches using the 555 to dim a LED but in these cases the LED was part of the circuit. How ...
3
votes
1answer
156 views

Brushed DC motor control MOSFET selection

I want to control a brushed DC motor of the below specification: Motor: Permanent magnet DC brushed motor Voltage: 180V Current: 5 Amps RPM: 1500 The control method is PWM switching through a ...
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0answers
59 views

PWM to proportional bipolar control with push-pull amplifier. Need input and opinions

I'm putting together a circuit to control a (small wattage) TEC device in a bipolar manner. The idea is to have a micro controller put out a 3V3 PWM signal, level shift it between +- 3 V and filter it ...
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1answer
101 views

Adding more LEDs to a current regulating circuit

I am modifying a current regulating circuit that was designed to power three LED lights (see figure below). The circuit is designed to maintain current through the LEDs at 1A. The LEDs should be off ...
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1answer
84 views

Inductor calculation for DC to DC converter

How can I calculate the value and characteristics of inductor in a DC to DC converter?
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2answers
221 views

Microcontroller PWM to bipolar push-pull amplifier issues. (level shifting)

I'm trying to design a circuit that allows a micro controller (arduino) to control a voltage to a load. The load voltage needs to be bipolar in nature (+- 3 to 5 V) for use in controlling a TEC. My ...
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3answers
151 views

Sin signal from PWM

I wrote a program in order to use Pulse Width Modulation to simulate a sinusoidal signal. Added a low pass filter to get rid of the noise and the traces of it being a discrete signal. Added a half ...
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2answers
90 views

PWM control of air core motor

I am driving an air core motor using PWM control from a microprocessor. The position of the air core is dictated by the combined magnetic field created by applying 2 currents to 2 coils (sine coil ...
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1answer
153 views

How to replace bulb with LED in a PWM circuit (car)?

I want to replace a light bulb in a Peugeot 308 SW with a LED. The bulb works (lights) normally, but the LED blinks. I thought they are controlling the bulb in alternative current but my digital ...
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6answers
105 views

Converting PWM to bidirectional square wave?

Is it possible to make bi-directional ( symmetrical) square waveform from PWM signal? Im talking about 40 kHz frequency and 0.5v /-0.5v peak to peak signal.
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2answers
319 views

How to make a 12V DC variable voltage supply with more than 30A output?

I have a SMPS capable of outputting 33A at 12V and I would like to make it have a variable output with full current potential, or close to it. Now, Is it possible to do it with a PWM-controlled ...
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3answers
100 views

PWM controlled variable resistance

I found this circuit design for constructing a variable resistor. Its seems that the resistance can be controlled by the duty cycle of PWM on MOSFET. Would you explain what is the purpose of having ...