Thermal Shutdown Circuit with Low Voltage and Low Power Consumption for Power Management IC

A thermal shutdown circuit with low voltage and low power consumption was designed for power management ICs(integrated circuits).In the thermal shutdown circuit,the PN junction of a transistor was used as a temperature probe,where the switch-on voltage rises,and the variation of the switch-on voltage falls,with an increase in temperature.Reswitch-on temperature was depressed by a feedback mechanism to avoid temperature oscillation.Simulation with the parameters for a 0.6 μm BiCMOS IC was conducted.The results show that the circuit has ultra-low power consumption(the static current is about 0.5 μA);the errors of shutdown temperature are less than 1.00℃ when the shutdown temperature is set at 150℃ and the voltage of power source is 2.5 to 5.0 V;and the errors of reswitch-on temperature are less than 0.01℃ when the reswitch-on temperature is set at 135℃.