## Forums Search for: PWM

## PWM Circuit for multiple heaters

inHello, I'm trying to make 3 PWM circuits to control 3 different thermoelectric coo= lers (peltier cooler) I'm aware that ideally you...

Hello, I'm trying to make 3 PWM circuits to control 3 different thermoelectric coo= lers (peltier cooler) I'm aware that ideally you shouldn't run these with a PWM, that's fine, and= I'm only using these in one direction, only as a heater. So I made a simple PWM, with a Linear Tech. PWM part, a high side FET drive= r and a FET. and the thing works ok for 1 heater, but once I plug t...

## PWM and dither

inHi, I need to control a solenoid valve using PWM but I have also some specifications about "the dither" in order to reduce friction etc.. I now...

Hi, I need to control a solenoid valve using PWM but I have also some specifications about "the dither" in order to reduce friction etc.. I now what the dither is able to do in theory. I now how to built an electronic circuit concerning PWM (I'd do that using a micro plus a MOSFET etc.) but I don't have any idea about "the dither". Should I sum another PWM with lower frequency to the hi...

## Feedback for low frequency PWM regulator

inI'm building a PWM regulator for an incandescent bulb. Some of thos was described in a thread called "RMS Approximation of PWM/Square wave". In...

I'm building a PWM regulator for an incandescent bulb. Some of thos was described in a thread called "RMS Approximation of PWM/Square wave". In any case. Since there is no inductor/diode/cepacitor in the output stage I'll be using an RMS converter (LTC1968). For the PWM section I'm using the MIC1557 (SOT-23 size 555 equiv) for a R-C sawtooth to a comparator (TLV7211a) inverting input. I can c...

## model for BLDC motor control with PWM

inHi everyone, I've an half H-bridge motor driver controlled via a PWM. We read current on the phase terminal and regulate the PWM accordingly...

Hi everyone, I've an half H-bridge motor driver controlled via a PWM. We read current on the phase terminal and regulate the PWM accordingly through a PID. The exercise is to play with all parameters (transfer function, sampling frequency, adc resolution, pwm resolution) in order to get the right precision on the output. I wanted to model the loop with something like MATLAB or Octav...

## I2C to PWM IC

inDoes anybody make an IC that takes I2C command and outputs duty cycle (PWM)? I need to control bunch of TECs from CPU and I2C-> PWM seems the...

Does anybody make an IC that takes I2C command and outputs duty cycle (PWM)? I need to control bunch of TECs from CPU and I2C-> PWM seems the most efficient (and smallest) way to do it. Any suggestion will be appreciated. Thanks Michael

## How to calbrate a DC voltage?

inI have a FET and a load and a micro outputting PWM. I want to convert the PWM to DC (low-pass filtered?) which will control the current...

I have a FET and a load and a micro outputting PWM. I want to convert the PWM to DC (low-pass filtered?) which will control the current through the FET. I also want to be able to calibrate the DC voltage such that for any given PWM duty-cycle I want to be able to adjust the resulting DC voltage plus or minus a yet-to-be-determined percentage. This will probably need to be done only...

## Voltage to PWM

inHi all, I want to make a V to PWM circuit. (For a servoed heater.) I drew a triangle wave into a comparator, and that seems simple enough. ...

Hi all, I want to make a V to PWM circuit. (For a servoed heater.) I drew a triangle wave into a comparator, and that seems simple enough. Though it will take a few IC for the triangle wave. (I guess I could use an opamp and dual comparator.) So I went searching for V-PWM IC's. Most are for SMPS controll, which seem overly complicated for what I want. I also want a fairly low...

## goofy PWM

inI need an isolated analog output (many of them, actually) with, say, 1 PPM programmability and linearity. An optocoupled DAC would be...

I need an isolated analog output (many of them, actually) with, say, 1 PPM programmability and linearity. An optocoupled DAC would be silly, so I'll use PWM. https://dl.dropboxusercontent.com/u/53724080/Circuits/PWM_WB_P470.JPG If I start at 200 MHz, and do a 20 bit (1 PPM) pwm, the output frequency would be 200 Hz. If I use a 3-pole lowpass filter (not too much delay) it has to be -...

## PWM for dc Motor

inHow much more efficient is PWM over ordinary dc? eg in terms of battery useage, can I double the life between charges? Hardy

How much more efficient is PWM over ordinary dc? eg in terms of battery useage, can I double the life between charges? Hardy

## Voltage to PWM chip (similar to class D)?

inFolks, Does anyone know an IC that can turn a control voltage into PWM and can handle PWM frequencies in the 50-1000kHz range? Similar to a...

Folks, Does anyone know an IC that can turn a control voltage into PWM and can handle PWM frequencies in the 50-1000kHz range? Similar to a class D driver but has to go down to DC. The changes in control would be restricted to the audio spectrum below 15kHz. The LTC6992 does this nicely but isn't precise enough. Same with 555-style timers or switcher chips. I am looking for better 1% and...

## Measuring PWM current?

inCan an RMS current clamp meter accurately measure the current of a PWM voltage? How else to measure PWM current without a shunt or direct...

Can an RMS current clamp meter accurately measure the current of a PWM voltage? How else to measure PWM current without a shunt or direct in-line meter? Thanks.

## PWM and motor control -- request clarification

inCould some electronics guru please clarify the following. I understand that Pulse Width Modulation (PWM) uses a high fixed frequency carrier...

Could some electronics guru please clarify the following. I understand that Pulse Width Modulation (PWM) uses a high fixed frequency carrier signal (e.g., triangle wave) and a low frequency modulation signal -- or even a DC level. If I were to use PWM for motor control, and use a fixed frequency triangle wave carrier, what would be the modulating signal in this case ? Is the output PWM sig...

## Wanted: Voltage mode PWM controller

inHi all. I need a basic voltage mode PWM controller for a buck converter project. I need a wide duty cycle range, like 5 - 95%. I don't need an...

Hi all. I need a basic voltage mode PWM controller for a buck converter project. I need a wide duty cycle range, like 5 - 95%. I don't need an error-amp in the ic, since this part is placed elsewhere in my circuit. So, a basic Ramp generator and a PWM comparator, and an output stage. An UC3843 would suit if it were voltage controlled instead of current. I've gone through Fairchild, ONsemi we...

## RMS approximation of Square/PWM signal

inDoes anyone have a way to approximate and RMS voltage from a PWM signal. I want to regulate the RMS voltage sent to a lightbulb, but do not have...

Does anyone have a way to approximate and RMS voltage from a PWM signal. I want to regulate the RMS voltage sent to a lightbulb, but do not have the room for the inductor and capacitor required to carry 20+ amps of current. I need to feedback a voltage to the PWM controller that is proportional to the RMS voltage of the output. I don't need an EXACT RMS conversion, rather a ratio would be fin...

## PWM MOSFET driver question

inHi all, I'm currently designing a full-bridge PWM controlled DC motor driver with a 24V/10A supply voltage. For driving each MOSFET...

Hi all, I'm currently designing a full-bridge PWM controlled DC motor driver with a 24V/10A supply voltage. For driving each MOSFET half-bridge, I selected the LM5106 driver IC. As the '5106 is only available in a 20mil lead spacing MSOP, I can't do any bench tests without designing a PCB right away, so I'd like to check up on things to prevent costly mistakes (this is my first PWM motor...

## RIsense Value for Basso's PWM-CM Model

Hello, I am trying to simulate a buck and a boost converter using Christophe Basso's generic PWM models (in LTSpice) for voltage mode...

Hello, I am trying to simulate a buck and a boost converter using Christophe Basso's generic PWM models (in LTSpice) for voltage mode controlled and current mode controlled switched mode power supplies. These models have an integrated PWM generator and power switch. These models can be found here: http://cbasso.pagesperso-orange.fr/Downloads/IsSpice/Final%20models.zip (alternati...

## Low power PWM controller, possibly the 555 (flame war coming)

inHi I am working on a small 100mW forward converter and I need a very low power PWM control. So the 555 comes up, along with some ultra low...

Hi I am working on a small 100mW forward converter and I need a very low power PWM control. So the 555 comes up, along with some ultra low power opamps. But, isn't there a PWM chips out there with low operating current. Sofar I found the TPS5110 with sub mA current consumption: http://www.ti.com/lit/ds/symlink/tps5110.pdf Anyone used one with lower current? Thanks Klaus

## PWM Sine Wave Inverter output problem

inDear All, I am building a PWM Sine Wave Inverter using H-Bridge IGBT Configuration. The inverter has the following stages: 1. A Sine Wave...

Dear All, I am building a PWM Sine Wave Inverter using H-Bridge IGBT Configuration. The inverter has the following stages: 1. A Sine Wave Oscillator 2. An unity gain inverting amplifier to generate inverted sine wave 3. A Triangular wave generator 4. Two Sets of Comparators to generate PWM waveform for positive and negative cycles 5. Two Half Bridge IGBT Drivers to generate A and A' s...

## PWM feedback

inThis is more of a practical question. I understand feedback and how it work= s and can design controllers. However, these have been for dc (non...

This is more of a practical question. I understand feedback and how it work= s and can design controllers. However, these have been for dc (non PWM) mot= ors using tachos with a dc output. What I want to know is how you achieve this with digital tachos which give = out pulses.=20 I am thinking that the set point is still dc as before (or software based) = and you just count the pulses f...

## PWM drive of DC contactor

inI have a DC contactor with a coil that draws about 4 amps at 24 VDC and=20 normally uses an economizer resistor of about 75 ohms to reduce the...

I have a DC contactor with a coil that draws about 4 amps at 24 VDC and=20 normally uses an economizer resistor of about 75 ohms to reduce the = current=20 to about 400 mA when pulled in (controlled by a delayed contact). But I = want=20 to use a PWM drive for another similar contactor (actually a 120 VAC = unit)=20 so it will work on DC and thus be more tolerant of AC line brownouts. Pr...