High-precision over-temperature protection circuit

Abstract

The invention provides a high-precision over-temperature protection circuit. The high-precision over-temperature protection circuit is characterized by comprising a PTAT reference current generation circuit, an over-temperature comparison voltage generation circuit, a reference voltage generation circuit and an over-temperature comparator, the over-temperature comparison voltage generation circuit and the PTAT reference current generation circuit serve as current mirror images of each other, the output end of the over-temperature comparison voltage generation circuit and the output end of the reference voltage generation circuit are connected with the negative phase input end and the positive phase input end of the over-temperature comparator respectively, and the output end of the over-temperature comparator serves as output of the over-temperature protection circuit. Whether temperature exceeds the over-temperature protection threshold value is judged by comparing the over-temperature comparison voltage and the constant reference voltage, so that when the product temperature is too high, an over-temperature protection signal is output, and a product is controlled to enter the temperature protection state. The circuit is simple in structure, the over-temperature protection trigger point is not influenced by the manufacturing process, and the high-precision over-temperature protection circuit is accurate, high in batch consistency and high in accuracy, can be used as an over-temperature protection module in products such as integrated circuit chips, MCU modules and switch power supplies, and has good market development value.

Description

technical field [0001] The invention belongs to the technical field of semiconductor integrated circuits, and in particular relates to a high-precision over-temperature protection circuit. Background technique [0002] Some integrated circuit products, such as power supplies and drive devices, often face the problem of high operating temperature and excessive heat generation, which will cause the circuit to fail to work normally or even burn permanently. This requires the integration of an over-temperature protection circuit in the circuit. The function of the over-temperature protection circuit is to monitor the operating temperature of the circuit, and to operate after the operating temperature of the integrated circuit reaches the set value, to complete the functions of shutting down the circuit and turning off the power supply, and to protect the circuit. [0003] Traditional over-temperature protection circuits such as figure 1 As shown, the triode with a threshold val...

AI Technical Summary

Problems solved by technology

Due to the deviation of the production process, the threshold value of the triode will fluctuate (such as figure 2 As shown in the simulation waveform shown), it is difficult to control the threshold of the over-temperature point: the low temperature triggered by the over-temperature protection will cause false triggering and affect the normal working range; the high temperature triggered by the over-temperature protection will cause The over-temperature protection function does not work, and eventually the temperature trigger point accuracy of the over-temperature protection is low, and the product yield rate using this over-temperature protection circuit is low.

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