TEC DAC Output Voltage vs Power showcases the power consumption of the TEC element when testing the sensing of the thermistor. The device is initially turned on, then the power resistor is heated through the use of an external heat source. The power of the TEC lowers when the thermistor senses a temperature increase on the TEC, causing the ADC voltage to change. As the heat is removed, the PI controller on the device changes the voltage output of the DAC to modify the power consumption and return to the setpoint for the ADC.

TEC DAC Output Voltage vs Power

The preceding plot compares the relationship between the DAC voltage and the same power output of the TPS63070. Since the DAC voltage (and the resistor network) bias the voltage of the TPS63070, the DAC voltage has a proportional relationship to the power output of the TPS63070.

Measured Temperature of the TEC Versus DAC Power highlights the inverse relationship of the power on the TPS63070 and the temperature of the TEC. As the TEC (power resistor) heats up, the power consumption of the TEC lowers. Inversely, an increase in the power consumption results in the TEC cooling. As the PI controller approaches the setpoint, there is a ripple of approximately ±0.2°C.

Measured Temperature of the TEC Versus DAC Power