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

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1answer
29 views

PWM or switch port programmatically for Servo

Is there a huge difference between using a PWM and switching a port through a program (like using switch) for operating Servos? For smooth movement is PWM necessary or switching using a program will ...
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4answers
96 views

Why do most PWM LED displays and backlights operate at a relatively low frequency?

All around me are a bunch of electronics: digital clocks, my laptop, a refrigerator, a dimmable flashlight, and more. What they all have is perceptible flickering of their displays due to PWM, ...
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0answers
42 views

Varying the Frequency of PWM Inverter Modulation Function

I'm modelling a PWM inverter with a triangular carrier signal, and a sinusoidal modulation function. In order to get certain frequency of sine wave out of the inverter, I need to vary the frequency of ...
0
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1answer
26 views

Board or product to drive 15 PWM/analog outputs from USB/serial connection

Ok, Let me explain: I would like to drive 15 analogs (0-12V) signal from my computer (based on user interactions/other not-so-cool stuff). This hardware has to be controlled over USB or Serial port ...
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0answers
71 views

BLDC motor control PCB

I am trying to make a PCB to control a Sensorless Brushless motor. I just wanted to know if it looks right. The IC I am using is a TB6588FG it has a 2.5A peak output current. I want to use it with ...
0
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1answer
68 views

Controlling current in a PWM circuit

I have a PSOC Cypress board which generates a 5V PWM signal to drive a laser diode. The idea is to design a programmable pulse which I could control the on-time period and current in the pulse. The ...
0
votes
1answer
35 views

Help for PWM circuit for 12 volts DC up to 1.3 A

Is there a way to do a fairly simple PWM circuit that will handle 12 volts DC up to 1.3 Amps? The 555 timers appear to fall in the 600 mA to 900 mA max power dissipation range. Attached is the basic ...
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3answers
74 views

EMI due diligence

I had an idea to use the World Semi WS 2801IC used for addressable led strips with a power mosfet driver so that each address can be tied to a high current (~1-1.5A) load. The chip indicates the PWM ...
0
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3answers
155 views

DIY current-limited 40A+ power supply to emulate LiPo batteries

I want to do some experiments developing brushless DC motor control hardware, and maybe wiring my own motors for my own edification. LiPo batteries aren't convenient enough, and I want ...
1
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2answers
265 views

Why is there so much overshoot in my LED circuit and how do I prevent it?

I'm trying to PWM a 5 meter RGB LED strip with a microcontroller. With this setup: simulate this circuit – Schematic created using CircuitLab I have built it on a breadboard and probed ...
0
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2answers
41 views

PWM control of Peltier with Arduino+Thermistor

I currently have this setup and would like to add automatic control over the PWM based on a thermistor reading. Any insights?
0
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1answer
52 views

Space Vector Modulation

Im looking to learn more about this topic so that I can implement it in an amplifier design. I've read around and understand most of the math behind it, but I'm still a little fuzzy on how to ...
0
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1answer
62 views

Shifting the phase of an Arduino PWM

This is a fairly simple question. Is it possible to use additional circuitry, connected to an Arduino PWM pin, to shift it's phase? As far as I can tell, the Arduino PWM pins can be configured for ...
0
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1answer
37 views

How to modulate Transceiver module for use with ATmega164PA

I am using a transceiver TFDU4101-TR3 to communicate with another device which has exactly the same transceiver. I bought this thinking I can communicate with the transceiver using my microcontroller ...
0
votes
1answer
56 views

How to use Turnigy MultiStar ESC with generic microcontroller? [duplicate]

I just got the Turnigy Multistar 20 Amp Multi-rotor Brushless ESC 2-4S. I have a motor and a battery hooked up to the ESC. On the three pin connector, I attached the brown ground wire to a ground ...
0
votes
1answer
70 views

n-channel MOSFET source load alternative

I'm trying to drive some RBG leds using MOSFETS. Let's say I have 2 individually RBG LEDS, each controlled by 12V, with each R, B and G with its own output to GND. What I want to control, is to be ...
1
vote
1answer
63 views

How to choose what a power supply to drive 2 x 10watt RGB LEDS?

I'm trying to figure out how to determine what power supply I should be using for different types of LEDs for this and future projects. I have 2 x RGB LEDS: Forward Current: 350mA Forward Voltage: ...
0
votes
2answers
100 views

Help to design an amplifier

I need help designing an amplifier that is capable of providing 1 W to an 8 Ohm speaker. I have 3.3 V, 5 V or 18 V supply available to power it. I also have only one power supply available that has ...
0
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0answers
31 views

Calculating power draw for LEDs and driver (TLC5941)

I am designing a backlit keyboard with 61 white LEDs. These will be individually driven by a TI current limited PWM driver (TLC5941). LEDs: 61 x Osram LCW JNSH.PC (Datasheet) Drivers: 4 x Texas ...
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2answers
65 views

Amplifier design

I am having trouble calculating values for this audio amplifier. Input comes from AVR PWM operating at 44.1 kHz with high being at 3.3V. The speaker is 8 Ohm and speced for 1 Watt. First two ...
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2answers
93 views

Variable Voltage Using PWM and Low Pass Filter

I am trying to control a steady DC output voltage using a Micro controller with a PWM duty cycle. With the current schematic, the Voltage on Vout is pulsing along ...
2
votes
1answer
109 views

Controlling speed of motor through L293D using TLC5940NT

I am trying to control a DC motor through an L293D. Ultimately I am controlling it with an Arduino, but I am trying to use a TLC5940NT chip as an intermediary to increase the number of outputs that I ...
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1answer
34 views

PWM input voltage regulation

I have a 12V DC motor that I plan to run in one direction with PWM input at 21A. However, in the other direction I want to drop the voltage to limit the speed. Ideally. the regulator would sit between ...
0
votes
1answer
105 views

Capturing PWM Signal on an Oscilliscope

I have a stepper motor that is controlled by PWM. I am trying to analyze the signal coming out of the controller on an oscilloscope. Ideally, I would like to capture, maybe 2 seconds of wave form so ...
0
votes
3answers
64 views

Capacitor on line with high frequency digital signal?

Capacitors act as a short for high frequency signals. If I place a capacitor on a digital 5V PWM line or perhaps a motor encoder line does the cap still act as a short to ground for the square wave ...
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2answers
147 views

130V DC Motor Control

I am interested in building a control circuit for a motor. More specifically this motor. The model I want to control is the 130V model, 0.48A, which should make it at ~62W for the motor, and 1/17 ...
0
votes
1answer
61 views

PWM Dimming results in input ripple due to excessive inrush current

I use a constant current SEPIC boost regulator ([TI LM3410X) to run a 8.5V 400mA OLED panel from a single Cell Lithium polymer battery. I have noticed that the input voltage ripple is too much (~1V ...
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3answers
191 views

Can PWM be used for PID controlling…

I am was wondering if an IC like the PCA9685(Datasheet) that generates PWM signals can be used in a PID controller for controlling a heated bed on a 3D printer. My understanding of PWM is that it ...
0
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1answer
88 views

How does a true sinewave inverter work?

I am an Electrical Engineering student, and when we were taught about inverters (at a power electronics course) we studied inverters using Sinusoidal Pulse Width Modulation. My question is do the ...
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votes
2answers
54 views

Complex LED drivers/circuits [closed]

Throughout my travels I've seen these very complex circuits that incorporate ICs for "i.e. dimming applications" that are included in designs with buck boost converters, etc. What makes LED driving ...
1
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1answer
65 views

How do I replace an existing servo with a geared DC motor?

I am a complete beginner, just getting into the world of electronics, in particular robotics. I have found a really nice open source set up that I want to build on and change for my own ends. The ...
2
votes
1answer
86 views

How to build LED dimmer for room illumination - PWM, low pass filter?

I want to illuminate a room. This will be done by two LED strips 60led/m, each 5m long, located along the tops of opposite walls. In order to get full light power, they together consume 4A@12V. ...
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2answers
97 views

What is the reason my ULN2003A overheats?

I'm driving some 12v fan motors from a microcontroller using ULN2003A Darlington array. Both total wattage and per-channel wattage are way below ULN2003a limits. Still, I found that when PWM duty ...
0
votes
0answers
70 views

Voltage Sag with PIC24 PWM Open-Drain Configuration

I'm experiencing some major voltage sag with an open-drain PWM output into an RC servo. I'm pulling up to +5V with an external pull-up resistor. I've tried using everything from a 1k-100kOhm resistor, ...
0
votes
1answer
43 views

555 servo controller “modulation input”?

Exactly as the question says. On the TI 555 Rev. C data sheet, what is the modulation input for the PWM circuit? Also, can I round the resistor and cap. to 10k and .022uf, respectively?
0
votes
1answer
84 views

PWM understanding

I am giving PWM to a MOSFET (50% duty). It switches about 8.5V to be fed to a phase of a motor. There are 3 such phases. Now, I am looking at voltage measured from these phases as well. I have ...
0
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0answers
61 views

How to drive Worldsemi “smart” LEDs

Let's get to it: The issue is about these cheap 6-pin 5050 package LEDs from Worldsemi. These LEDs contain an IC with a simple serial interface running at 800kHz. You can daisy-chain those LEDs ...
0
votes
0answers
22 views

Variable load using PWM

I am trying to design a variable load by PWM. From what I have understood I need to feed the base of a BJT (for current amplification) with my PWM signal. The maximum voltage that we need at the ...
1
vote
1answer
94 views

Arduino PWM pin vs digital pin PWM simulation

Do I understand it correctly from this thread, Why do some pins have `~` signs next to their numbers?, that the PWM pins generate a square wave signal independently from what the code uploaded to the ...
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vote
3answers
152 views

Complementary H-Bridge Motor control

I have some concerns in a motor control board I designed. Sometimes the MOSFETs unexpectedly start to burn. I suspect one of the reasons is the thin track (0.2mm) I have in my flexible board (0.2mm), ...
2
votes
1answer
52 views

Using both PWM and Timer2 interrupt in PIC18F25k50

Background I'm working on lead-acid battery charger and experimenting with battery desulfation. I want to draw current vs time graph on graphic LCD and see: how high current spikes I have measure ...
2
votes
1answer
100 views

EMI suppression low frequency

I'm dealing with a PWM generator which drives a load at 12V with pretty high currents (5-10A) The PWM frequency is in the band of 100-200 Hz. Which is the best choice and right configuration of ...
0
votes
0answers
91 views

Trying to use SPI to communicate between dsPIC (33EP) and LED driver (LT8500)

I'm trying to setup SPI to generate PWM signals on the LED driver LT8500. Below is my code: ...
0
votes
3answers
88 views

PIC18F25k50 - 10-bit PWM resolution with 8-bit timer?

Im messing around with PIC18F25k50 standard mode PWM. I found something weird. Datasheet says, that PWM is 10-bit, and timer is 8-bit. How that can be? Is that datasheet is wrong, or my english ...
2
votes
2answers
68 views

Simple PWM regulator, current measurement without high-side current sensing

I have a very simple Lead-Acid battery charger with slow (1kHz) PWM regulator. I would like to add current and voltage measurement (with PIC18F ADC - 200kSPS). I have no problem with voltage ...
1
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1answer
42 views

PWM photodiode bias circuit control voltage

Cant the photodiode bias regulator described here, Fig 6 be controlled with a PWM input? The RC loop right at the control input seems to filter PWM frequencies, but I am not sure if there are any more ...
2
votes
1answer
64 views

PIC24 Open-Drain Config for 5V PWM Operation

I'm running a PIC24HJ series processor with a supply voltage of 3.3V. I need my PWM signal to be 0-5V, not 0-3.3V. Can I simply connect the PWM line to a 5V supply with a pull-up resistor? Or do I ...
2
votes
3answers
155 views

BJT switch vs amplifier mode

I'm getting really confused about a specific BJT circuit. I want to control LCD brightness and contrast as suggested here. Apprently a capacitor is used to filter PWM output to the contrast pin, ...
0
votes
1answer
77 views

LCD brightness and contrast control with PWM

Is it reasonable to control LCD brightness and contrast directly with the PWM pins of an Arduino, or would it be advisable to use a capacitor/filter to get a constant analog voltage? I assume human ...
1
vote
1answer
91 views

Using L293 H-Bridge to drive DC motor with PWM

I want to drive an DC motor with ability both to change direction, and torque. Obvious solution: PWM + H-Bridge. I've been planning to use a PSoC4 for controller, and L293DNE for the H-bridge, which ...