The Thermo-Electric Cooler (TEC) is found in many applications that require precision temperature control. The small size of the TEC allows precision thermal control of individual components such as fiber optic laser drivers, precision voltage references, or any other temperature critical device. The temperature-critical components are integrated with a TEC and a temperature monitor into a single thermally-engineered module. An added bonus with TECs is the ability to heat, by reversing the current.

TEC control requires a reversible power source capable of providing positive and negative voltages. To accomplish this from a single supply, an H-bridge circuit can be used. While linear supplies offer low noise, their poor efficiency requires large components and added thermal insulation to prevent the regulator waste heat from loading the cooler. Alternatively, two synchronous buck circuits with complementary drivers provide a higher efficiency supply that can deliver bipolar power from a single positive supply. Forced pulse-widthmodulation control of the two output voltages allows current to be sourced and sinked. During current sinking, power is recovered and sent back to the supply line. The MAX1968 is a highly integrated H-bridge PWM switchmode driver designed for Peltier thermoelectric coolers (TEC) modules.