Mosaic
Well-Known Member
This is an attempt to use peltier modules direct from the 120VAC mains. 170VDC rectified and smoothed.
I will double insulate as the supply isn't isolated.
So far I am looking at using FET PWM with an input capability of 200VDC to generate around a 4A avg. with soft start current. I plan on using (3) series mounted 12V, 60W (peak) peltier units. This means a 0.1 ohm current sense feeding into a low pass and then the comparators.
The challenge is the control circuitry operates at lower voltages, eg. a TL494 PWM driver is good to about 40V.
The Tl494 might pull perhaps 20mA to operate so a resistance divider could drop the 170VDC supply to 1/10 to provide the TL494 power. Perhaps 3.5W additional heat load as a result.
A stock PC supply is a bit too bulky for the application space overheads.
thx
I will double insulate as the supply isn't isolated.
So far I am looking at using FET PWM with an input capability of 200VDC to generate around a 4A avg. with soft start current. I plan on using (3) series mounted 12V, 60W (peak) peltier units. This means a 0.1 ohm current sense feeding into a low pass and then the comparators.
The challenge is the control circuitry operates at lower voltages, eg. a TL494 PWM driver is good to about 40V.
The Tl494 might pull perhaps 20mA to operate so a resistance divider could drop the 170VDC supply to 1/10 to provide the TL494 power. Perhaps 3.5W additional heat load as a result.
A stock PC supply is a bit too bulky for the application space overheads.
thx