Quote:
Originally posted by pHaestus
What does one use to PWM a pelt pulling that much power Bill?
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Big FET's, well not so big a couple of the irfp460's i got infront of me now could cope max drain 20amps (500v)
Then all you need is a pic to take an analouge (or thermocouple depending on how your feeling) input to generate the squarewave to switch the fets.
Here was my idea from a while back, i believe its quite novel although i could be mistaken.
Take the pwm control circuitry out of an atx (or any smps) powersupply and replace it with a temperature controlled pwm generator. Then as the temp changes the pic can alter the voltage direct, and on a hysteresis curve, which then eliminates hitting the tec with pwm itself but alters the voltage quickly but smoothly instead.
The other option could be a max336cpi (also at my desk ironically) to build a digital resistor with 256bits of resolution.
Also I think i still got a link of a manafacturer you might want to contact, they do the 220w tec cheap (like $15 min order 10) aswell as the 172w module for like $11. But they also make PWM resistant module iirc.
Whats your overall goal BillA?
]JR[