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

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50 views

What is the name for an IC that accepts an analog voltage and outputs a proportional PWM signal?

I want to isolate an analog signal. One way of doing this is to convert the analog signal to PWM, isolate the pulses with an optoisolator, and filter the PWM on the other side. Obviously I could do ...
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3answers
127 views

LED without resistor

I know Ohms Law, i know leds need resitors. My scenario is this: I need to make a little circuit that controls 2 RGB leds with a 9 Volt battery. This gives an avergare o 5 hours of light before the ...
0
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2answers
25 views

PIC18F14K50 with 8Mhz crystal and 50Hz PWM

I'm looking to generate between 50Hz to 150Hz square waves with a PIC18F14K50, which is running with an 8MHz external crystal (XT). Apart reading an analogue value for the frequency from a pot and ...
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1answer
62 views

BS170 Mosfet equivalent for PWM application

I'm currently using a Mosfet BS170 to drive LEDs from a 3.3V 1Khz PWM output. The problem is I would like to use more current (something around 2A max at 12V Max) than the 500mA allowed by the BS170. ...
0
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3answers
160 views

Is this PIC micro-controller powerful enough to drive PWM LEDs?

Short Question Is a PIC24F16KM202 (Datasheet) powerful enough to vary the brightness of 12 LEDs from 12 PWM outputs without any visible stepping of brightness levels? ...
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1answer
38 views

Tools for simulating software-driven PWM

I want to simulate a software driven PWM. So, I need to program the controller output based on the transient/instantaneous feedback from some part of the circuit in the simulation (i.e. the software ...
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1answer
32 views

TPS40211 PWM LED driver topology

I've recently been trying to figure out an LED driver circuit for my 32V, 0.7A CoB emitter. I settled on the TPS40211, since it ticked all the boxed in terms of input voltage range, output, etc. I ...
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2answers
75 views

What should I do if my MCU output is higher voltage than the Max Gate V on my N Channel MOSFET?

The V(GS) Gate to Source Threshold Voltage for a MOSFET I would like to use is listed as Min 1.5, Typ 1.9, and Max 2.3V. I am working with a Teensy3.1 that outputs 3V on the PWM pin. Do I need to ...
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1answer
71 views

Mosfet overheating under pwm

Here the schematic of a very simple circuit I know I don't have the flyback diode on the motor. And the MIC4422 is flipped in the schematic. I want to control the high power motor with this high ...
0
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1answer
36 views

Creating a PWM signal using PIC18F4520

I am trying to create a 100ms period pwm signal (10Hz) with a PIC18F4520, I followed the PR2 equation to help me create this signal I have a 20MHz clock frequency with a prescaler of 16 and a PWM ...
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0answers
77 views

X-Ray tube Current Control based on PWM

I want a control module to be implemented in FPGA(Altera Cyclone IV running on NIOS2) using VHDL which controls current flow to a X-Ray tube. The scenario is I have the expected current value say ...
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1answer
51 views

dedicated IC for PWM

Is it okay to drive leds through PWM directly from Microcontroller? OR should I use a dedicated PM generator IC like NCP5623? the Microcontroller uses software pwm. what are the pros and cons of both
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1answer
59 views

When to use a digital potentiometer vs PWM and mosfet?

When would you use a digital potentiometer over PWM and a mosfet/transistor? I don't understand the advantages/disadvantages between the two.
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0answers
40 views

how to resolve mismatch between PWM resolution and sensor resolution?

I have an application that uses a high resolution sensor. The actuation loop runs on this sensor's feedback. Thus, the PWM resolution is limiting my achievable resolution in the actuator's movement. ...
0
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1answer
34 views

DC motor operation with a varying voltage

So I was studying PWM control of DC motors and it got me confused.Here the input is pulsated.This will obviously turn the motor fully on or fully off.Wouldn't this create vibrations?I know pulse ...
0
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1answer
52 views

What is a good microcontroller for PWM signal generation? [closed]

I want to build a Pulse Width Modulation board, something that would allow me to send different PWM signals to the devices connected to the board. My main criteria - is being able to send at least 4 ...
0
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1answer
32 views

PIC reset with PWM

I'm using a PIC18F4550 to control a DC motor with PWM. When I use a PWM of above 50% it works well, but when it starts to go below 50% the PIC resets. I have separated supplies for the PIC and the DC ...
0
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1answer
41 views

Teensy 2.0++: How to get a PWM output from pins OC2A & OC2B

I'm doing a project that requires a lot of PWM's and I've gotten 6 of the 9 PWM capable pins to work, but I'm struggling to get the last 3 running. To get the OC1A-C Pins running a PWM, I did this: ...
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1answer
53 views

Brightness control with PWM dimming LED driver LM3406/06HV

I have an changing input voltage. I would like to feed it into LM3406 and have varying brightness from the Led. So I go through the datasheet. However,the only information and characteristic of the ...
3
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4answers
144 views

How to heat up MOSFET within seconds?

I'm using low power MOSFETs (N channel-STP4NK60ZFP and P channel- IRF9530). The aim is to build a demo kit for students to study the thermal characteristics of MOSFET at variable frequencies and duty ...
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1answer
39 views

PWM of Diaphragm pump

I'm pretty new in this area so sorry if this question seems foolish. I have a 12V 20Lpm Diaphragm pump that draws around 18 Amps. I'm using it on a home built herbicide spray system to help deal ...
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1answer
89 views

ATTiny 841 PWM at 450kHz

I have managed to output 500kHz PWM at 50% duty cycle on PA2 TOCC1 of ATTiny841. ...
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0answers
41 views

Controlling a servo motor on an LPC2103 microcontroller

I'm still a beginner on deep embedded systems development. I would like to know how to control a servo motor without using PWM, since I didn't actually learn anything about it on my classes and I'm ...
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1answer
135 views

Getting PWM to work on STM32F4 using ST's HAL libraries

I'm trying to switch to the ST HAL libraries and can't seem to get the PWM to work. Compiles fine, just doesn't start. In my main() I call the Timer initialization function: ...
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1answer
66 views

generating sine pwm in orcad pspice

I am trying to design a PWM inverter in Orcad PSPICE where i am using a Vpulse source from library to generate MOSFET triggering pulses for H-bridge and it works fine for square waves. But i if i ...
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2answers
25 views

relay for USB camera control

I need a little help with some electronic components: From my RC system a I get a signal which is 3.3V PWM, 5 volt and GND. I need to make a 5V PWM out of this for my camera. PWM values are ...
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1answer
63 views

How does PWM work on an Xbee Wi-Fi Module S6B?

I've read that the PWM on an Xbee is 15625 Hz and that it is somehow different from the PWM used to run motors. What is the difference? Note: The XBee PWM is not the same type of PWM used for ...
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0answers
38 views

Control of a single-phase PWM inverter

When designing a controller for the canonical DC-DC converter, I found a good number of models (linearized transfer functions) that could be used to design a compensator. I am attempting to do the ...
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0answers
51 views

DC/DC Converter MOSFET switching

I am currently building a SEPIC converter. The signal arriving from the MOSFET driver to the MOSFET seems all good, however the Vds doesn't seem to follow the drivers signal and it makes the MOSFET ...
2
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3answers
131 views

Debugging when oscilloscope grounds cures the problem

In a nutshell : My circuit behaves erratically I connect the 'scope to find out why The problem disappears In particular, this concerns the circuit in my last question although this is not ...
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1answer
74 views

how to convert digital signal(PWM) into analog signal [duplicate]

analog signal can b easily made by using PWM in micrcontroller but it is not a real analog signal. please tell me how can i convert PWM into real analog signal
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1answer
139 views

Constant current driver - direct pwm dimming

I recently picked up a cob bulb of Ebay that came with a constant current driver. Tried to dim it using a mosfet and PWM signal of an Arduino, but it resulted in a very loud ringing/humming from the ...
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2answers
89 views

What's a good set of PWM values to make sine waves for a 3 phase motor?

I'm building a synchronous rotating spark gap for a tesla coil. I have a working mcu (Kinetis K64F) driving a 230volt inverter board and it spins a 3 phase synchronous motor. The motor is a ...
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1answer
70 views

What is the harmonic content of a PWM signal?

Suppose I'm using a 3.6 kHz carrier to reproduce a 60 Hz sine wave. To properly design a filter for this application to hit a specific harmonic distortion target, I need to know the harmonic content ...
2
votes
1answer
90 views

Signal on top of PWR line

See edits at bottom: I'm trying to design a network of circuits (see example below), in which a modular circuit (non-static, can be change, with high variability in current draw) is connected on any ...
0
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1answer
106 views

Driving IR LEDs using PWM - measuring current & current source questions

For a project I'm currently working on, we're trying to drive 940nm IR LEDs (Kingbright L-934-F3C) using PWM, regulated by an Arduino Uno. We've run into several issues during our prototyping process ...
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0answers
57 views

How to discharge a capacitor quickly…(filter of an H-bridge/inverter)

I have used four IGBTs to build an H-bridge… the inputs of the h-bridge are SPWM and are programmed in a way as shown below: The output of the H-bridge is a three level pwm(as expected), and then its ...
7
votes
3answers
810 views

Why do RC applications use such a small PWM duty cycle?

I know that RC applications, such as a drone, use PWM signals to drive the motors. This PWM signal is mostly 50 Hz (0.02 s). The pulse itself varies from 1 ms to 2 ms. So a ...
17
votes
4answers
1k views

How to clean up a noisy signal?

I'm controlling a 4-pin PWM PC fan from a PIC16F684 with the fan speed driven from an ADC reading of a proximity sensor. This all works ok. I wasn't originally planning to use the tachometer output ...
0
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0answers
44 views

Integral cycle (PWM) control of AC voltage input to heater

I'm designing an open loop voltage controller for my water heater element. I'm planning on using a triac and controlling it using integral cycle control. There is no temperature sensor feedback , just ...
0
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1answer
66 views

Problems with IGBT driving

this is my first question, so please be patient with me :-) The problem is with IGBT we are using, IRG4PC40S datasheet available here> link It has to control a 1kW heat block to keep a temperature ...
0
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3answers
132 views

How do I use pin5 to control duty cycle of a 555 based PWM?

I have built a simple PWM using a 555 IC to drive a motor for an optical chopper and I want to be able to use the output of the chopper signal as a speed correction feedback for the PWM. I think I ...
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1answer
44 views

Current Source version of TLC5940 (current sink LED PWM driver)?

Is there a current-source equivalent of a TLC5940 (current-sink) PWM LED driver? I'm working with a large number of linear resonant actuators (LRAs), each of which only uses ~50mA, but must be driven ...
0
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0answers
42 views

PWM lithium-ion charger

I want to make a custom lithium-ion 18650 standard cell charger as I will be charging 100s of them (recycling old laptop batteries). Base on my research, lithium-ion cells use constant-current, ...
0
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0answers
88 views

what are the standard ways to generate sine wave using Hbridge and micro controller?

I'm in to driving an h-bridge made of two ir2110 and the pulse width modulation(pwm) signals will be provided by the micro controller. I did some some groundwork to understand how sine pwm is ...
6
votes
1answer
190 views

Why does my PWM amplitude vary with duty cycle?

I'm controlling a 4-pin PWM fan from a 5V PIC and before going too far I'll say that everything is working fine but I'm just not understanding what I'm seeing on my scope. The fan has a 12V supply ...
0
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3answers
245 views

AVR/Arduino: Output 2 pwm waveforms with 90 degree phase shift

So far, I was able to get two outputs at the correct resolution (35kHz-75kHz at a resolution no worse than 0.7 kHz) using the code below. I'm wondering, now, how I can get a phase shift between the ...
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2answers
104 views

LM317 and PWM grounds

I have a question regarding the LM317 and PWM. My circuit receives +12v and has three grounds (R,G,B) that are PWM. I need to drop the voltage down to 3.2 volts from the 12 volt source. NOTE: I know ...
4
votes
4answers
389 views

Rc network placing R before C vs after

simulate this circuit – Schematic created using CircuitLab Using a rc network to smooth a PWM signal from a microcontroller, to a true analogue voltage. What will be the effect of having ...
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0answers
50 views

Convert voltage to Resistance

I have a constant current source output, how can I convert this to a voltage with another voltage as reference. Electronically not theoretically with math? I will have an output of +3.3Vmax from a ...