Over-temperature protection circuit

Abstract

The invention discloses an over-temperature protection circuit which comprises a resistor R23, a resistor R21, a triode Q21, a comparator with a hysteresis function, a voltage feedback loop module and a first current mirror connected with the voltage feedback loop module. One end of the resistor R23 is connected with the voltage feedback loop module, and the other end of the resistor R23 is grounded; one end of the resistor R21 and an emitting electrode of the triode Q21 are both connected with the first current mirror, and the other end of the resistor R21 and a collecting electrode of the triode Q21 are both connected with the resistor R23 and then grounded. The hysteresis function is realized in the comparator, the chip area can be reduced, the cost is saved, specifically, a switch of an internal circuit is controlled through an output signal of the comparator, so that the equivalent size of a load MOS (Metal Oxide Semiconductor) tube is changed, the equivalent width-length ratio of the load MOS tube is controlled, the hysteresis function is further realized, and the over-temperature protection circuit is simple and convenient.

Description

technical field [0001] The invention relates to the technical field of over-temperature protection, in particular to an over-temperature protection circuit. Background technique [0002] Power supply integrated circuit products have increasingly penetrated into all aspects of modern life. As a protection mechanism, the over-temperature shutdown function can effectively shut down the circuit when the chip temperature is too high, thereby avoiding abnormal circuit function or burning. The current over-temperature protection circuit is generally realized by using a comparator to compare a reference voltage that does not change with temperature and a voltage with a negative temperature coefficient that decreases with temperature. Among them, the hysteresis function is achieved by changing the reference voltage. The implementation of voltage is more complicated. Contents of the invention [0003] The purpose of the present invention is to provide an over-temperature protection...

AI Technical Summary

Problems solved by technology

The current over-temperature protection circuit is generally realized by using a comparator to compare a reference voltage that does not change with temperature and a voltage with a negative temperature coefficient that decreases with temperature. Among them, the hysteresis function is achieved by changing the reference voltage. Voltage implementation, the implementation is more complicated

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