Arduino + seperate IC for PWM + HBridge Module --- How should I approach this?

Hi everyone,

I am trying to design a pwm controller module that has a PWM pulse generating IC and a HBridge to control a 6A thermo electric module

This module heats one side and cools the other and we can flip the sides by reversing the polarity.

A standard PWM IC that controlls a power N channel mosfet and a HBridge configuration is what I am looking for; I was thinking of putting 4 such modules connected to an arduino and I would like each module to have a configurable PWM frequency with a configurable duty cycle. I would like the frequencies to be between 5Khz-64Khz. The arduino, will have an data logging ethernet module and so I don't want to use its clock cycles too much.

As you might have guessed, the idea here is to design a temperature controller with a thermo electric module along with a fan and possibly a laser module (may be).
Given this situation, how can I precisely control the PWM frequency. 555 timer is not sufficient since its not programmable. There are quite a few ICs to look into, but I am getting confused when RTCs are getting into the picture; its better to ask :-). Here are the questions I am grappling with:

  1. What IC is suitable to generate PWM cycles? I prefer to communicate it with I2C or SPI.
  2. I would like to use a H Bridge IC, but most of the ICs are under 3-4 amps. I would like a to scale the amperage to about 10amps if possible. I am assuing that DIY H Bridge is the way to go...?
  3. What should I use to make the H Bridge: N,P channel enhancement mosfets or NPN/PNP transistors or darlingtons?
  4. I am assuming that I should throw in a few opto isolators to isolate all the H bridges from the rest of the circuit.
  5. I am open to reducing the upper level frequency if the DIY H Bridge brings in new issues...

Any advice or pointers is highly appreciated.

Thanks,
Pradeep

Use a power supply controller, mosfet, flyback diode, inductor and filter caps. LM494 is one such PWM IC and is used in every AT/ATX power supply. Use one of the current controlled examples from the datasheet for the IC. Cooling devices are more current based than voltage.