I am working on a project that involves the use of high-power thermoelectric cooler modules for use in cooling metallic material in a circuit. The TEC modules need to be able to move up to 30 watts of heat energy, and since TECs aren't that efficient, I need a circuit that can drive 60 or so watts into them. (Hand-waving going on there. This isn't the meat-and-potatoes of the post. Please continue on...)
My question:
What's the most efficient circuit that would allow a control signal to throttle the power through the TEC modules? The signal is coming from a 0-+5v DAC but it can be multiplied, divided, or shifted as needed.
Ideas I've tossed around thus far:
1) Linear/power op-amp/variable voltage regulator with series pass transistor
-->Each of these dissipate more power between "full on" and "full off" than the TEC modules themselves. Grossly inefficient.
2) Half-bridge/H-bridge/pulse-width modulation/variable switching supply
-->The PWM H-bridge is currently what I'm using. With low Rds-on MOSFETs, I can get FAR better efficiency than the linear stuff in 1).
I also considered using a national semiconductor (now TI) "simple switcher" variable switching regulator, but could not figure out how to control the output voltage with something besides a resistive divider for voltage feedback. There were other issues with the switching regulator as well
-->lowest output voltage was above zero.
If anyone has any other suggestions regarding a better/improved way to do this, or if you feel this is already the best way (the PWM and H-bridge), I would appreciate any feedback. Along the lines of PWM, I built circuits to discretely generate the PWM signal (ramp, comparator, level-shifting, the works.) If anyone has any suggestions on an already-made pulse-width modulation IC, I'd appreciate feedback on that, also.
Thanks in advance.
My question:
What's the most efficient circuit that would allow a control signal to throttle the power through the TEC modules? The signal is coming from a 0-+5v DAC but it can be multiplied, divided, or shifted as needed.
Ideas I've tossed around thus far:
1) Linear/power op-amp/variable voltage regulator with series pass transistor
-->Each of these dissipate more power between "full on" and "full off" than the TEC modules themselves. Grossly inefficient.
2) Half-bridge/H-bridge/pulse-width modulation/variable switching supply
-->The PWM H-bridge is currently what I'm using. With low Rds-on MOSFETs, I can get FAR better efficiency than the linear stuff in 1).
I also considered using a national semiconductor (now TI) "simple switcher" variable switching regulator, but could not figure out how to control the output voltage with something besides a resistive divider for voltage feedback. There were other issues with the switching regulator as well
-->lowest output voltage was above zero.
If anyone has any other suggestions regarding a better/improved way to do this, or if you feel this is already the best way (the PWM and H-bridge), I would appreciate any feedback. Along the lines of PWM, I built circuits to discretely generate the PWM signal (ramp, comparator, level-shifting, the works.) If anyone has any suggestions on an already-made pulse-width modulation IC, I'd appreciate feedback on that, also.
Thanks in advance.