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

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8 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
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2answers
449 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
60 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 ...
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1answer
82 views

Other ways to vary voltage besides PWM

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 ...
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2answers
30 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 ...
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1answer
47 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 ...
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3answers
34 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 ...
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3answers
47 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 ...
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1answer
36 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 ...
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1answer
69 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
45 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 ...
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0answers
26 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 ...
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1answer
53 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 ...
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0answers
127 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 ...
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2answers
32 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 ...
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1answer
45 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 $$ \frac{(\text{OCROA}+1) \times \text{prescaler} \times \text{timerCount}}{\text{FCPU}} $$ ...
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1answer
48 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 ...
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1answer
29 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 ...
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0answers
18 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
61 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
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0answers
17 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 ...
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0answers
34 views

what LED driver to choose to drive the high power LEDs

I want to design a circuit with arduino and high power LED. so basically I have 10 red 1W LED , 5 1W blue LED, I want to control the red group and blue group respectively, moreover each group of color ...
0
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3answers
62 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 ...
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2answers
35 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 ...
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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), ...
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1answer
57 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 ...
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0answers
18 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 ...
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1answer
28 views

Problem with PWM motor driver

I'm using my custom circuit in the figure for driving dc motors. I'm providing a PWM (25khz). While trying the activation threshold (minimum duty cycle that activates my motor) experimentally I have ...
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1answer
12 views

Chip with one oscillator provide different brightness (PWM) for multiple LEDs?

I'm working with the PCA9531 chip described as The PCA9531 is an 8-bit I2C-bus and SMBus I/O expander optimized for dimming LEDs in 256 discrete steps It is a chip that provides 8 PWM outputs ...
0
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1answer
35 views

Peak Current of PWM

I am designing a controller for a hotwire cutter. As measured, the resistance measured is 1 \$\Omega\$. The power is switched on and off with a 555 astable mode to produce a pwm of \$V_{on}=12\$ V and ...
1
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1answer
57 views

Emulating greyscale on a 1-bit LCD

I have an LCD (the DOG-M 102x64, with a uc1701 controller) that I am driving (over SPI, but that's somewhat irrelevant) from an AVR (ATMega16 @ 8 MHz) - all in all, a fairly low spec'd screen with a ...
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1answer
53 views

Sallen-Key filter using LM358 doesn't act as supposed to when fed a 31.25 kHz PWM

I want to create an Analog Voltage by filtering a PWM signal. After some googling, I found an active low pass filter topology with -40db/decade called the Sallen-Key topology. I tried implementing a ...
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1answer
46 views

Testing an h-bridge using the power supply and/or signal generator to control a DC motor

I'm using the DRV8836 (datasheet here) from Texas Instruments and can't seem to get it to work. Does it require a PWM (pulse from the signal generator) or am I able to drive it with only the DC power ...
0
votes
1answer
110 views

PWM with Oscillator does not dim LED display as expected

I have a fairly successful attempt so far at driving an LED display with an Arduino Mega 2560. The Display sequences work well on their own and the Arduino seems to be doing its job sending the ...
0
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0answers
29 views

BLDC Motor Control - Determining PWM Switching Frequency

I've read that the PWM switching frequency should be anywhere from 200hz (high inductance motor) to 64khz (low inductance motor) in order to minimize torque/current ripple at perhaps the expense of ...
0
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1answer
103 views

BLDC motor waveforms

I'm trying to drive a brushless motor (BLDC) with an ATMEGA328p I use Timer0/1/2 to generate 3 different PWMs @ 62Khz. First I tried (only absolute values) $$A = \sin(T)$$ $$B = \sin\left(T + ...
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votes
1answer
78 views

how to design high power LED light circuit,

I am new to electronics, want to prototype a LED light with 3 red led, 3 blue led and 3 white led. All the led are 1W high power LED. Each group of color can be controllable respectively and I want ...
0
votes
1answer
46 views

Filtering noise off of PWM signal

I am trying to measure the resistance of a nichrome wire that has a PWM (1000Hz and different duty cycles between 0 and 100%) voltage applied to it from a 5.0V regulator. The setup I have in mind ...
1
vote
1answer
53 views

help with 555 timer to dim led driver

I am trying to build some DIY LED fixtures to light my saltwater aquarium. They need to be dimmable, and I want to dim them with Pots for convenience versus a controller. It will probably be clear by ...
1
vote
1answer
56 views

Control LEDS with PWM and transistors

I have three transistors that are each connected to 5 LEDs like so. I am attempting to increase and decrease the current through the LED's in a linear fashion by increasing the current in the base ...
0
votes
2answers
56 views

How to add the two output of a PWM IC?

I need to sum output A and output B of a PWM (UC3526AN) because each output have a maximum duty cycle of 0.45. I try with 2 diode and a limiting resistor(R1) for the led inside the optocoupler ...
0
votes
0answers
14 views

voltage level shift at the input of PWM IC (UC1526 )

I am using UC1526 in open loop configuration (pin2 and 3 connected) and I am inputting a voltage to pin 1 to control the duty cycle. I notice that pin 1 which control the duty cycle need a minimum ...
0
votes
1answer
34 views

Driving 5 RGB LEDs using a microcontroller

I need to run 5 differnet rgb LEDs from a microcontroller. All the LEDs will be producing the same color so there will only be 3 separate PWMs (1 for each channel of rgb.) My problem is most ...
1
vote
1answer
56 views

30x Incandescent light bulb in parallel ? + dimming

I'm trying to connect 30x small incandescent light bulb in parallel (1.5v / 300mA). But I'm having some issue designing the supply and dimming circuit. Does it just work like LED's for the ...
0
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1answer
33 views

PWM in 8051 with PCA counter

I read in documentation of AT89C51RC2, that I can make one of 5 ports to generate PWM signal if I set properly some registers. Some things I don't understand. I don't know what PCA counter is and how ...
2
votes
1answer
60 views

FIltering a PWM signal?

The first box is my modulating signal and the last box is my demodulated signal (filtered signal) I used my signal to change the duty Cycle of a PWM modulator (fix PWM frequency and variable Duty ...
0
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0answers
68 views

Control Output Power using PWM from Arduino

I am trying to make a simple control loop to power up a lamp and with that control the temperature, for that I am using an Arduino as microcontroller. The lamp I am using is a DC 12V 20W, so we ...
0
votes
1answer
61 views

PWM speed control for 90vdc motor

I built this circuit and it seems to work if i use a the same power supply to the motor that is powering the IC. I am using an LED in place of the motor for testing. But the circuit does not work ...
0
votes
1answer
108 views

What's the relationship between ESC pwm input and output?

I'm using ESC(Electronic speed controller) to control outrunner brushless dc motor. As you know ESC detects ppm signal between 1ms and 2 ms approximately. So my ESC detects signal between 4% and 9% ...
0
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2answers
62 views

Space vector PWM signals

I have done few BLDC motor controllers with trapezoidal modulation and they work fine. Now i'm trying to build another one with space vector modulation but as it doesn't work well i'm getting more and ...