The invention discloses an over-temperature protection circuit. The over-temperature protection circuit comprises a
constant current generation circuit, an output
control circuit and an output shaping circuit. The
constant current generation circuit is used for providing a stable current bias for the over-temperature protection circuit. The output
control circuit is used for converting a temperature
signal into an
electric signal and controlling output of the over-temperature protection circuit. The output shaping circuit is used for shaping output of an output
signal of the output
control circuit. A first
resistor and an M1 tube are used for real-time detection of a
chip temperature and making a response. The over-temperature protection circuit is simple in structure, and does not need any high-precision
voltage comparator. The component number is low,
temperature control precision is high, a turn-off
signal can be generated at a heat turn-off temperature
threshold point accurately, debugging is convenient, the over-temperature protection circuit has a temperature
hysteresis function, heat oscillation of the
chip near the temperature
threshold point is prevented, and the over-temperature protection circuit is suitable for usage in chips of power
supply management or LED driving and the like.