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

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24 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
112 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 ...
-3
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1answer
56 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
0
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1answer
65 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 ...
2
votes
0answers
54 views

Is it possible to control the speed of DC motors with Arduino's analogWrite() using analog pins? [migrated]

I'm trying to control the speed of two DC motors that are connected to a dual H bridge. I always used digital PWM pins with analogWrite() to change the speed, but ...
3
votes
1answer
61 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 ...
0
votes
1answer
66 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
84 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
66 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 ...
0
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0answers
40 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 ...
6
votes
3answers
761 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
votes
0answers
15 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
votes
1answer
45 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
votes
3answers
64 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 ...
-1
votes
1answer
32 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
33 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
49 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
156 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
votes
3answers
148 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 ...
0
votes
2answers
74 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
370 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 ...
0
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0answers
45 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 ...
1
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1answer
70 views

How do I use 5V PWM from PIC to control 12V fan?

I'm not sure if that title explains it well enough, but I have a 12V PWM PC fan which I want to drive using a 5V PIC. The fan has 4 pins, GND, +12V, PWM and TACH. The TACH is a speed sense pulse from ...
0
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1answer
58 views

Motor noise interfering with I2C

I built a robot using the Arduino Due with all the sensors running at 5V over I2C. There is a level shifter on both I2C lines. The motors are controlled using a VNH5019 motor driver carrier from ...
7
votes
2answers
613 views

Controlling a very small DC motor with PWM?

I have a very small DC motor (from a Walkman), I would like to control the speed from a micro-controller. For that I would like to connect a MOSFET in series and apply a PWM signal to its gate in ...
1
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2answers
71 views

open-drain reliability problems

I've built a run of simple boards like the one shown below to control LEDs in automobiles. The boards have twenty of the NX3008 mosfets in an open-drain configuration as shown, which are controlled by ...
0
votes
1answer
96 views

Other ways to vary voltage besides PWM [closed]

I am trying to control an electronic throttle, the ECU (Pi Innavo M220) I am currently running allows for PWM, but several other components are already drawing a lot of power. The M220 Has digital and ...
0
votes
2answers
42 views

How to calculate the RMS of an AC PWM?

I am looking at a servo, which is driven by PWM. The PWM signal itself modulates NOT DC but a sine AC, so when Throttle is set to 100%, I can see a rather nicely drawn sine wave. But when Throttle is ...
0
votes
1answer
57 views

Variable vin AC to fixed DC power supply design.. Simplest And Small

Okay, so bare with me on this one please... First post on this stack and still refreshing my memory on electronics in general. So basically i'm working on a project which generates a varying AC ...
0
votes
3answers
39 views

PWM module and inrush current from motor

I'm trying to setup a power feed for a milling machine using an old DeWalt drill motor. I've got a 13.8v 20A power supply and a Kemo M195 20A PWM module. My concern is the inrush current from the ...
1
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3answers
50 views

How to do PWM with least ripple in software?

I'm interested in generating a PWM signal in software on a micro (it is not possible to use hardware PWM in this case). It is simple to use (for example) a loop with a counter that counts to 255 and ...
0
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1answer
41 views

Double VCC across motor

I have a motor which runs in only one direction when excited by a square PWM at 500kHz with a voltage of 5.6V across the two pins of the motor. Consumption is around 100mA. I have a 1.8V square ...
0
votes
2answers
120 views

Arduino PWM control MOSFET

I have a bit of a problem that in hoping someone can shed some light on. I have a 4 wire fan (from a power mac g5) and I found that the pinout is positive, negative, PWM and rpm output. It's a bit ...
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1answer
47 views

How to controlle a motor with arduino

I have 2 og those 12v motor and a 12v battery http://www.enigmaindustries.com/Motors/Bosch_EV_Warrior.htm I want to know what s the best solution to controle the motor with an arduino Uno. Is the ...
0
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0answers
42 views

Trilevel PWM for H-Bridge, potential shortcircuiting in inverter

Here is the schematic I have followed, mine is not exactly the same, but for the most part, it follows the same method, generating a sine and triangle reference, generating a square wave and then ...
0
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1answer
80 views

pulse charging lead acid battries effects and side effects

I am developing a solar charger which charges lead acid batteries.I would like to clear a few of doubts on this issue. I am using IR2110 gate driver for driving 2 n-channel mosfets in an half bridge ...
0
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0answers
165 views

Raspberry PI PWM Common Anode 5v 12v Lamp Circuit

i'm not an Electronical engineer, i prefer to write codes. But lately (since about 2-3 months) i finally had the balls to connect something to the raspberry PI's gpio. Two days later i already tested ...
0
votes
2answers
35 views

Controlling servo torque

TL;DR : Can I control a servo's torque by PWM'ing a PWM ? I'm thinking about buying a dynamixel AX18 and I would like to be control it's output torque. If I modulate the input command, I expect the ...
0
votes
1answer
54 views

Atmega328 fast PWM (mode 7) of timer 0 not working as expected

I am blinking an LED on PORTB5 using timer 0 in mode 7. The time between blinks is computed as $$ \frac{(\text{OCROA}+1) \times \text{prescaler} \times \text{timerCount}}{\text{FCPU}} $$ ...
0
votes
1answer
68 views

1N4148 Diode for 3V-5V PWM

I have 2 PWM ports, one generates 5V PWM and another at 3V. But only 1 will be generating at a time. However, their output is going to a same wire or pin. So, to avoid the current to pass into each ...
0
votes
1answer
47 views

What determines BLDC rotation direction when using trapezoidal commutation with BiPolar Switching?

Block commutation seems simple enough, the rotation is determined by the order in which the 6 step sequence is executed (ex. cw 1->6 or ccw 6->1) What's confusing is how bipolar switching changes ...
0
votes
0answers
42 views

How does Mean Well LDD range DC-DC constant current drivers handle dimming?

Mean Well LDD range DC-DC, constant current buck drivers have dimming function. 5v PWM signal allows you to dim the LEDs. Without PWM, you get the full rated current output. Now knowing anything ...
2
votes
1answer
74 views

Switching supply burning mosfets, what is happening?

I have been working on a SEPIC converter for an electronic cigarette power supply. This application involves using two 3.7v INR batteries in parallel, rated for an appropriately high current ...
0
votes
0answers
41 views

PWM output pulse variation is not showing in proteus

I want to generate the pulse based on analog input giving to ADC and convert ADC value to PWM signal using LPC2138 ARM processor. I am able to dubug in Keil software in which it works perfectly as I ...
0
votes
3answers
72 views

Light intensity is dropping on large LED bulb display when it sequences

I have assembled an LED display controller using an Arduino Mega 2560. The controller runs a display sequence on an array of (25) large LED bulbs that draw about 125 mA each. It also has a smaller ...
0
votes
2answers
50 views

Logic level conversion for servos

I'm trying to spy on the state of servo communications with a RC receiver and optionally change the output. Unfortunately my controller is 3.3v while the servo logic is ~5v. I'm trying to figure out ...
1
vote
1answer
47 views

What the output isn't correct when I use a switching power supply?

I have a circuit that it is a STM32F103RET6(Reference Manual) board and one LCD. everything work very well just one thing! PWM! when I use my J-Link debugger to supply the circuit(or USB connector), ...
1
vote
1answer
61 views

How do I tell if my amplifier is voltage-to-voltage, voltage-to-current, etc

I have an amplifier, which is essentially an amplifier and a motor driver in one (link to data sheet), and I'm having an embarrasingly hard time trying to figure out what/how much it is amplifying. I ...
0
votes
0answers
22 views

Noise with PWM Motor Driving Circuit

I'm using the circuit of this question: Problem with PWM motor driver The problem of the past question is solved using a 1200k resistor and lowering the frequency to 4 Khz: now I have noticed, using ...