I am trying to set up a h-bridge circuit to control the TEC, no PMW.( In schematic I use the resistor instead.) I also used microcontroller to control the input of H-bridge with a DAC circuit connected to the microcontroller, and I have thermistor as feedback. The problem is how to add a switch circuit between the only output pin of DAC and the two pins of h-bridge. Or any analog device can do that. In h-bridge, one pin will be grounded and the other pin will be at certain voltage, which is controlled by the microcontroller. THX.