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.