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

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23 views

Beaglebone Black - DC Motor causes ADC to hang?

I'm working on a regenerative-braking project with a DC motor. My Beaglebone Black drives a small DC Motor using a TB6612FNG motor driver from Sparkfun (datasheet): Everything runs fine except that ...
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0answers
49 views

Efficient way of controlling many LEDs

I am working on a project which is going to have approximately 50 LEDs. These will be status LEDs to show whether an appliance is On/Off. I will also need a brightness control for the LEDs so PWM is a ...
1
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0answers
56 views

Is this a case of PWM interference?

I have a Electronic Speed Controller (ESC) being controlled with Pulse Width Modulation (PWM) from an Arduino. When I put my hand close to the cables the signal goes screwy until I move my hands away....
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0answers
35 views

PWM Input and Multithreading [on hold]

So I am trying to read a PWM signal from a 433 MHz receiver (EZUHF) on a Beaglebone Black. I have currently not set this up yet as I am trying to figure out the best way to do so. I could not ...
0
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1answer
36 views

Solar panel powered regulated output voltage collapses after short run-time

I have a PWM DC motor controller for a water pump. Input voltage 24 V large solar panel (the ones you get on houses). The PWM has a L7812 so outputs 12 V max. Pump 12 V, 0.9 A. Everything starts ...
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2answers
61 views

What is meant by 8-bit resolution on the AD8802's PWM input?

I am using a PCA9685 (outputs 12bit PWM) to control an LED driver, AP8802. The LED driver datasheet states (on page 11, paragraph 2): A Pulse Width Modulated (PWM) signal with a max resolution of ...
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3answers
49 views

Most efficient way to PWM a boost converter

I am stepping up ~4V to 12V to power an LED strip with a boost-regulator. I don't want to run the LED strips (3 leds in series with a resistor) at full brightness so I need to PWM them. Is it better ...
3
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0answers
45 views

PWM Solar Battery Charger for 192V battery

I bought a solar controller for my 192V solar system that did not work as advertised (instead of MPPT, works with ON-OFF cycles - Chinese ripoff - but that is offtopic).I want to redesign the control ...
4
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1answer
99 views

Transistor PWM Generator (No ICs) for practical application

I want to produce a good quality PWM signal with transistors(BJTs, FETS, etc..). I do not want to use an IC at all(learning to use transistors properly). I'm currently using a BJT Astable Mutivibrator ...
0
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3answers
60 views

Negative Voltage Reference For Instrumentation Amplifer

I'm trying to measure a variable resistance, RX, creating an AC voltage with two PWM and applying it to a wheatstone bridge. The PWM goes from 0 to 3.3v and to measure the voltage differential i'm ...
0
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1answer
61 views

Hbridge Circuit output

I am trying now to implement Hbridge using 2*p-2*n mosfet "ZXMHC6A07T8 " from zetex semiconductor , I used the offered spice model and I connected simply as and I connected to two PWM what I do ...
0
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1answer
31 views

Can't understand a variable in the formula used to determine CDTY to set duty cycle of PWM on cortex M3 (SAM3X8E)

I want to generate complementary PWM on an Arduino due. For that purpose I am programming the cortex M3 using the PWMC library. In order to set the duty cycle I have to set a value in CDTY channel ...
1
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1answer
39 views

How to calculate the dead time to incorporate in the complementay PWM input to an H-Bridge designed using MOSFETs?

I am working on making an autonomous robot. Right now, I am involved in designing an H-Bridge using discrete components for my robot. I am almost done with the H-Bridge design, and want to test it ...
0
votes
2answers
56 views

DC-DC buck converter controlled by ATTINY - optimize PWM for maximum resolution

I got a solenoid with the following data: 1.25W 24V 460Ohm resistance Inductance value unknown I'm working on a sensor PCB which also needs to control the force of the solenoid. The sensor PCB is ...
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0answers
76 views

Can a solar charge controller prevent voltage drop?

I have a solar panel that is putting out 14 volts in direct sunlight. Whenever I apply a load the voltage drops to below 11 volts. Will adding a solar charge control keep the voltage at a continuous ...
0
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0answers
72 views

Why I can see LCD Flicker over 100Hz backlight?

I studied that Human cannot notice 60Hz or higher light flicker. But I can see LCD flicker at 180Hz backlight PWM LED. (I've changed backlight LED PWM frequency and checked...10~100Hz : flicker. ...
3
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0answers
38 views

Problem Outputting 2.5 Khz Signal ATTiny85 with Digispark

I am relatively new working with the Digispark IDE and I am having some issues with something that should be really simple. I am trying to output a 2.5 kHz square wave signal, that will oscillate +/-...
1
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1answer
60 views

5V PWM 0-100% duty cycle output should generate 0-100mV

The project I am attempting is: Arduino UNO receiving a data record from a battery data logger one particular value (State of Charge) is extracted and sent to a PWM output going through a low pass ...
0
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0answers
26 views

Pwm motor Driver

Hello, I was trying to make a motor driver for my project which can power motors at 12V.. For this, I made the same circuit as shown in the image but it is not working for some reason and the ir2110 ...
0
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2answers
86 views

How many LED's can a TLC5940 16-Channel LED Driver power?

A TLC5940 can sink up to 120ma per channel. I am having difficulty finding the max current for the entire chip on the Datasheet. Is there one, or is there another limiting factor for this chip? ...
1
vote
1answer
51 views

Multiply analog and square signals

I'm trying to implement a poor man's amplitude modulation by multiplying analog signal with PWM output. The simulation result: Why I get negative voltage? How it can be?
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1answer
56 views

Setting a simple PWM on atmega328 at certain frequency

I'm having a hard time to set a 16 bit PWM on atmega328 that works with frequency of 50Hz and have a duty cycle that can be varied. I also have my doubts that if I can have an ADC working together ...
0
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0answers
36 views

Why do I need an esc to control a brushless motor if I can use pwm? [duplicate]

I'm looking at building a drone and everywhere seems to suggest that I need to controll the motors with an esc. It seems I send a signal to the esc with pwm. If I search "pwm brushless motor" I get ...
0
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0answers
39 views

Need Help with PWM Motor Speed Controller Circuit

I am using the following circuit to make my PWM Motor Speed controller. I just replaced the MOSFET IRF510 with IRF540 and LM555 with NE555. I found the schematic on the web. My motor is 12V rated ...
2
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2answers
51 views

Safe dead time limit on 19Khz PWM sine wave inverter

I'm buiding a 60Hz sine wave inverter based on 19Khz PWM generated by a PIC16F883 (lookup table) using a half bridge with 4 x IRF2807 - switching a pair of low-side/high-side. I'm using my own ...
0
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0answers
25 views

Class D Amplifier

For a piezomotor control I've used a class D amplifier TAS5162. PWM is provided directly to it with a microcontroller. I've made the same circuit as mentioned in the datasheet but instead of getting ...
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1answer
367 views

What do you call a 1:3 turn ratio transformer?

I need a small surface mount or slightly larger transformer with a 1:3 turn ratio that will triple my voltage from 3.3 to 9.9 volts. I have been literally searching the internet for such a thing and ...
0
votes
0answers
69 views

Audio POT with FET and PWM

I've been trying to build a simple audio pot to be controlled with PWM with an arduino, but I'm not sure why it doesn't work. I could do it with a LED (not directly which is simple, but with a FET), ...
0
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0answers
23 views

Achieving PWM wattage control w/o causing overcurrent fault?

I'm working on a project where I need to create a very compact PCB for a vaporizer. The target maximum power output is 15W. Currently I'm planning to use a TI TPS61088 boost regulator to boost a ...
2
votes
1answer
116 views

A question on PWM frequency of a DC motor

I'm planning to pwm-control four of the following motors by a single ArduinoUno: http://uk.rs-online.com/web/p/axial-fans/8179151/ For some reason the nearest pwm frequency I can set is 31kHz. The ...
0
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2answers
73 views

Arduino - Pulses get unstable when updating PWM duty-cycle

I'm trying to obtain stable pulse trains when adjusting the duty cycles wth an Arduino Uno board. In my actual project I need to use 4 adjustable PWM output pins at a fixed 25kHz frequency to control ...
0
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2answers
86 views

VHDL:CLOCK DIVIDER with duty cycle

I want to generate a 15MHz clock from a 60 MHz clock. The 60 MHz clock has a duty cycle of 50%. The output clock of 15 MHz must have 25% duty cycle. How the following code needs to be modified to vary ...
14
votes
5answers
999 views

Is there an ideal PWM frequency for DC brush motors?

I'll be using a microcontroller to create a PWM signal for motor control. I understand how PWM and duty cycle works, however I am unsure about an ideal frequency. I do not have my motor in yet, so I ...
0
votes
1answer
113 views

mosfet bootstrap explained [closed]

I'm trying to get a hold on bootstraps for high side n-mosfets. as i currently understand it, it works somewhat like this: when pwm is high, mosfet is closed and capacitor is loaded to 12V. when PWM ...
1
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1answer
31 views

Effects of using a different PWM frequency than specified on device

I am wiring up a fan speed control circuit that creates a PWM frequency that is used by a PWM fan (the fan and its specs are pictured below). The fan claims that its PWM control is done through a ...
2
votes
3answers
270 views

Measuring current - shunt resistor or current transducer or something else

I have to measure current which is sine with 37Hz frequency 1350 mA(DC) + 190 mA(AC). The voltage in circuit is generated using PWM 27V, 600 Hz, PWM dithering adds alternating part of current. I want ...
0
votes
1answer
49 views

How to check currently which PWM device is active and in which pwmchip on BeagleBone Black?

I would like to control a servo motor using PWM. I have loaded the following .dtbo's in the slots in bone_capmgr directory as shown below: ...
2
votes
2answers
109 views

Strange Distortion from Second Order Active Low Pass Filter

I'm feeding a 250KHz PWM audio signal from an ATtiny85 into a second order active low pass filter: The output is then fed into a decoupling capacitor and then into an LM324 amplifier. The output ...
0
votes
0answers
23 views

TLC5940 at 8bit

Since I really don't need all them 12 bits of depth, I was wondering if the 5940 has an 8bit mode one can use? Reading the datasheet didn't quite help, and googling mostly yielded question by fellas ...
0
votes
3answers
109 views

Convert PWM to Analog using a DAC chip in order to emulate a Potentiometer for audio

I'm trying to control audio level/gain (from line or amplified signal) using an Arduino. I do not want to use SPI, for this project I can only use the PWM outputs, thus I do not want to use a digital ...
0
votes
2answers
170 views

What will increase output volume (dB) on a Piezo Transducer?

I need to achieve 110dB at 25khz from a Piezo Transducer. According to the datasheet, the resonant frequency of the Piezo is 25khz and at 10 vrms it will produce 110dB. I will be using an ...
0
votes
2answers
29 views

electronic speed control of 3 post compound DC motor

I've got a 12V DC winch motor with two field posts and an armature post (compound motor). Currently direction is controlled by four solenoids. Here's a diagram which boils this down two the two ...
1
vote
0answers
45 views

Troubleshooting HIP4081

I'm driving four N-channel MOSFETS (IRFLIZ44N) with a HIP4081, and the circuit looks like the following: The MOSFETS are driving a peltier module, and the input pins of the HIP4081 are being driven ...
0
votes
3answers
114 views

A mosfet switch for PWM signal

I was wondering if my circuit will work. The 5V signal is coming from a microcontroller, based on a condition. If its 1(5V) I want the PWM signal to be received by the motor. If its 0, the motor ...
0
votes
1answer
43 views

Beaglebone PRU PWM to Audio Signal

I was wondering if its possible to convert the high frequency PWM output from a Beaglebone Green's PRU into an analog audio signal. I was looking at building a low pass filter and I was wondering if ...
4
votes
3answers
224 views

How to increase mosfet switching speed, and decrease switching losses?

I hope this is not a too broad question, but what are the best practices to achieve fast switching on a MOSFET driven by a PWM signal? My current knowledge tells me I can do two things: 1 - To use ...
0
votes
1answer
132 views

Is this schematic good?

Here is schematic for DC motor control. Using this I can drive motor in both directions and also send short pulses to motor, to move it only a little bit in desired direction. Let me explain schematic ...
0
votes
1answer
45 views

Weird op-amp voltage increase when using AC-DC power supply

I'm trying to create a PWM signal to dim an LED. I came a across this circuit: When I tried it out on a breadboard powered by a 5v supply coming from my USB Digilent Analog Discovery, it worked great....
-3
votes
2answers
165 views

PWM vs ESC for speed control for Arduino quadcopter

I'm from a computer programming background, but I'm interested in combining hardware with software, so I'm playing around with Arduino. Currently going through things on things needed to build a ...
0
votes
3answers
64 views

Techniques for driving inductive load, e.g DC motor, with PWM and constant current

I'm having trouble getting full torque out of a DC motor at anything other than full speed with a PWM driving circuit. Assuming the problem is inductance of the coils, what can be done besides ...