PWM Circuit for multiple heaters

Started by Fibo in sci.electronics.design3 years ago 47 replies
PWM

Hello, 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

Started by Pasquale in sci.electronics.design9 years ago 22 replies

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...

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...


Understanding PWM of Motor (current problem)

Started by amdx in sci.electronics.design9 years ago 25 replies

Hi All, I've been having a discusion about PWM of DC motors on an electric vehicle forum. I keep seeing the idea that battery current is...

Hi All, I've been having a discusion about PWM of DC motors on an electric vehicle forum. I keep seeing the idea that battery current is different than motor current when using a PWM controller. As quoted below. http://www.4qdtec.com/pwm-01.html This site says this; "You should see from the above that, if the drive MOSFET is on for a 50% duty cycle, motor voltage is 50% of batt...


noise from pwm

Started by bob in sci.electronics.design9 years ago 4 replies

I have a pwm that takes AC from the wall, and without an isolation transformer, turns it to a ~+-170V switching supply. I'm using the pwm to...

I have a pwm that takes AC from the wall, and without an isolation transformer, turns it to a ~+-170V switching supply. I'm using the pwm to power a custom device (about 6ohms and 0.15H). The problem I'm having is that there is noise everywhere. Specifically I have a hall effect current sensor wired in the pwm power line going to the device. I hooked the sensor to a scope and can see the DC o...


Feedback for low frequency PWM regulator

Started by JMini in sci.electronics.design9 years ago 64 replies

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...

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...


Converting PWM to Analog

Started by Anonymous in sci.electronics.design9 years ago 1 reply
PWM

Hi all, Currently, I have a microcontroller that puts out a 1000Hz signal but the low-pass filter I have built only converts PWM to analog for...

Hi all, Currently, I have a microcontroller that puts out a 1000Hz signal but the low-pass filter I have built only converts PWM to analog for a PWM carrier frequency of about 10kHz. Is it possible to adjust the PWM frequency that will work for the filter? I'm using a 3rd order, op-amp LPF, shown in this link.. http://www.eetasia.com/ART_8800105813_499489_AN_785b6341.HTM (hit view thi...


model for BLDC motor control with PWM

Started by alb in sci.electronics.design2 years ago 4 replies

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...

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

Started by Michael in sci.electronics.design2 years ago 17 replies

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...

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?

Started by DaveC in sci.electronics.design2 years ago 20 replies

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...

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

Started by George Herold in sci.electronics.design8 months ago 18 replies

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. ...

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

Started by John Larkin in sci.electronics.design2 years ago 45 replies

I 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 -...


Analysis Of Pulse Width Modulator With Motor Control

Started by seryuz in sci.electronics.design9 years ago 1 reply

http://img255.imageshack.us/img255/2396/pwmmotorcontrolcr7.jpg how to analyse the Pulse Width Modulator with Motor control? How can we...

http://img255.imageshack.us/img255/2396/pwmmotorcontrolcr7.jpg how to analyse the Pulse Width Modulator with Motor control? How can we make an analysis for this circuit. Can we make something mathematical? it says: Designing a PWM Circuit The concept of PWM inherently requires timing. Two 555 timer ICs and some potentiometers can be used to generate a PWM signal, and since PWM pro...


PWM for dc Motor

Started by HardySpicer in sci.electronics.design5 years ago 30 replies

How 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)?

Started by Joerg in sci.electronics.design3 years ago 127 replies

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...

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...


PWM and motor control -- request clarification

Started by Daku in sci.electronics.design6 years ago 24 replies
PWM

Could 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

Started by powerampfreak in sci.electronics.design8 years ago 18 replies

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...

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

Started by JMini in sci.electronics.design9 years ago 44 replies

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...

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 detector?

Started by Anonymous in sci.electronics.design9 years ago 12 replies

Hello all, I am designing an automotive product (operates 9 to 16VDC) that will drive a regulated high current 10 amp load with a NPN low side...

Hello all, I am designing an automotive product (operates 9 to 16VDC) that will drive a regulated high current 10 amp load with a NPN low side drive transistor. It will maintain average current to the load via PWM (400Hz 1% to 99% duty cycle) and sense resistor. My question, I want a way to shut the load down in the event the PWM controller flakes out and gets stuck high. This would be...


PWM MOSFET driver question

Started by Richard Rasker in sci.electronics.design9 years ago 5 replies

Hi 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...


A multi processor PIC computer :-)

Started by Jan Panteltje in sci.electronics.design7 years ago 40 replies

A multi processor PIC computer :-) ftp://panteltje.com/pub/multi_processor_PIC_LED_color_controller_hardware_img_2002.jpg I modified my LED...

A multi processor PIC computer :-) ftp://panteltje.com/pub/multi_processor_PIC_LED_color_controller_hardware_img_2002.jpg I modified my LED color controller a bit so it has 3 independent hardware PWM channels. One PIC is the master, is controlled via ethernet, and its PWM unit drives blue. It forwards the other color levels via very fast RS232 to 2 other PICs, one does the red pwm, and the...