An over-temperature protection circuit

Abstract

The invention discloses an over-temperature protection circuit, which includes a resistor R23, a resistor R21, a transistor Q21, a comparator with a hysteresis function, a voltage feedback loop module, and a first current mirror connected to the voltage feedback loop module; One end of the resistor R23 is connected to the voltage feedback loop module, and the other end of the resistor R23 is grounded; one end of the resistor R21 and the emitter of the transistor Q21 are connected to the first current mirror, and the other end of the resistor R21 is connected to the collector of the transistor Q21 Both are connected to the resistor R23 and grounded. The present invention implements the hysteresis function inside the comparator, which can reduce the chip area and save costs. Specifically, the output signal of the comparator is used to control a switch of the internal circuit, thereby changing the equivalent size of the load MOS tube and controlling the load. The equivalent width-to-length ratio of the MOS tube realizes the hysteresis function, which 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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