PROTECTION CIRCUIT, SEMICONDUCTOR DEVICE, AND ELECTRIC APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a protection circuit having both proper functions of overcurrent protection and overtemperature protection.

SOLUTION: The protection circuit includes: a first resistor for detecting a current applied to a circuit to be protected as a voltage; a reference voltage generating circuit for generating a reference voltage; an overcurrent detection circuit having an output to become high impedance when the voltage does not exceed the reference voltage and an output to become a predetermined voltage when the voltage exceeds the reference voltage; an overtemperature detection circuit including a temperature detection element having a resistance value varying in accordance with a temperature, a second resistor connected in series to the temperature detection circuit, a transistor having a control electrode connected in common to the output of the overcurrent detection circuit and to a connection point between the temperature detection element and the second resistor, operating in response to the voltage of the connection point when the output of the overcurrent detection circuit becomes high impedance, and operating in response to the predetermined voltage when the output of the overcurrent detection circuit becomes the predetermined voltage; and a control circuit for controlling so as to protect the circuit to be protected in response to the output of the transistor.

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