That is good stuff. I understand the issue more clearly, for sure. Shouldn't be too difficult to fit a gate driver circuit in the box. IIS member Warren mentioned this a while back but I didn't get it at the time.
I need to get to the bottom of pwm frequency - resolution seems self explanatory. I estimate it takes several seconds to indicate an increase in temperature of the cold finger.
I am guessing that 60hz is adequate, perhaps less. The strategy is to estimate the pwm value linearly for setpoint temperature and dither either side to maintain temperature. Changes in ambient air temperature are used to recalibrate pwm values - avoiding high, low switching.
EDIT:
Quote:
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The TEC drive voltage, however, does not need to be DC—a suitably fast (kilohertz range) pulse-width modulated (PWM) signal will also work as long as the PWM frequency is faster than the TEC's thermal time constants. http://www.sensorsmag.com/electronic...ric-cooler-993
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Thanks Chris.