As mentioned, thermoelectric cooler (TEC) is a solid-state heat pump which transfers heat from one side of the device to the other. The direction of the heat flow depends on the polarity of the applied voltage. Figure 4-2 shows a typical TEC module. Typically, when connecting the positive end of the power supply to the red wire, and the negative end to the black wire, the top side of the TEC will be cold and the bottom side will be hot.

Figure 4-2 Typical TEC Module

TEC modules differ in power that they can handle and the operating resistance they have. A TEC module with appropriate power rating should be used to maintain the goal system temperature under all conditions. To fully leverage the voltage/current capabilities of the TPS63810, there is an optimal range of resistance that the selected TEC should meet. The shaded area in Figure 4-3 shows the operating area, for example, the output voltage and current, of the TPS63810 when driving the TEC module, when the input voltage is 3.3 V. The specific operating points for several values of the TEC element resistance are shown with different lines. The TPS63810 can drive the TEC module with up to 5.3 W when operating in forward direction (when sourcing current), and up to 1.5 W when operating in reverse (when sinking current). The user can determine if cooling or heating is more important, and appropriately configure the polarity of the TEC module.

Figure 4-3 TPS63810 Operating Area When Driving TEC Module