● High Efficiency Single Inductor Architecture

The SGM41299 is a monolithic thermoelectric cooling (TEC) thermostat driver device with two-stage feedback amplifier. The device includes a differential driver (output) stage, an internal 2.5V output voltage reference and two zero-drift, rail-to-rail chopper amplifiers. The first chopper amplifier biases the sensed temperature signal and another is an error amplifier for compensating the closed loop temperature control. This amplifier can be used with a digital controller as well.

The TEC is driven differentially between a linear push-pull stage and a pulse-width modulation (PWM) switching stage. A linear push-pull stage forms one of the arms of the differential output which has a relatively high gain and saturates if the error signal is not near zero (> 2.5%). This means that the TEC is effectively driven by the other arm. The other arm has a lower gain, and high frequency PWM switching driver that can drive the TEC with high efficiency. The PWM switching driver output is passed through an LC filter to remove large voltage ripple before reaching the TEC. It can sink or source current for both the heating and cooling modes connected to the TEC and stabilize its temperature at the set point.