A Bandgap Reference and Over Temperature Protection Circuit Designed for TCXO Chip

This article designed a bandgap voltage reference source with a low temperature drift, high power supply rejection ratio for the TCXO chips , and design the sensitive reaction of thermal protection circuit is used to protect TCXO chips. The structure of self-biased current source and differential operational amplifier is used in the bandgap reference, And the over temperature protection circuit controlled oscillator on or off by a NPN transistor to detection the circuit current.The simulation results show that the range of the voltage output is not more than 0.78 mV when the temperature changes at -40 to 125, The power supply rejection ratio in the circuit is as high as 95dB; the oscillator is turned off When the temperature is greater than 150 degrees,and it´s restart when the temperature is less than 130 degrees, and it turn off needs less than 0.071 S, restart needs less than 0.064 S. The circuit can provide a stable reference and good temperature protection effect, which has great practical value for the TCXO chip.