Ic power supply protection circuit

Abstract

The present invention provides an IC power protection circuit the cost of which can be reduced while offering the same functions as a surge protection circuit and reverse connection protection circuit. An error amplification circuit, which is a part of the IC power protection circuit, is positioned and integrated within an integrated circuit. A transistor, which is another part of the IC power protection circuit, is positioned as a stand-alone element that is separate from the integrated circuit. The integrated circuit includes a sensor signal processing circuit that processes a signal of a sensor. A transistor protects the integrated circuit against a surge voltage from a battery terminal. A resistor is positioned between an output terminal of an error amplifier and a base terminal of the transistor to provide reverse connection protection. Another resistor is connected between a ground and a connection point between the above resistor and the output terminal to provide overvoltage protection for the integrated circuit. A starting resistor is connected between a collector and base of the transistor.An IC power protection circuit functions as a surge protection circuit and reverse connection protection circuit. The IC power protection circuit includes an error amplification circuit, positioned and integrated within an integrated circuit and a transistor, is positioned as a stand-alone element that is separate from the integrated circuit. The integrated circuit includes a sensor signal processing circuit that processes a signal of a sensor. A transistor protects the integrated circuit against a surge voltage from a battery terminal. A resistor is positioned between an output terminal of an error amplifier and a base terminal of the transistor to provide reverse connection protection. Another resistor is connected between a ground and a connection point between the above resistor and the output terminal to provide overvoltage protection for the integrated circuit.

Description

technical field [0001] The present invention relates to a power supply circuit, and more particularly, to a power supply protection circuit for an integrated circuit that supplies power to an integrated circuit having a withstand voltage lower than that of an externally supplied power supply. Background technique [0002] As a power supply circuit of an integrated circuit, there is a power supply circuit of an in-vehicle electronic control device described in Patent Document 1. This Patent Document 1 describes a power supply circuit for enabling a control power supply of an in-vehicle electronic control device in a state where a power switch is turned off. [0003] And, like the power supply circuit described in this patent document 1, the power supplied from the battery is supplied to the CPU via a constant voltage power supply circuit (regulator (regulator)) (with a lower withstand voltage than the power supply voltage supplied from the outside). integrated circuits). ...

AI Technical Summary

Problems solved by technology

[0008] Therefore, in the prior art, only the cost of the surge protection circuit or the reverse connection protection circuit has become a cause of an increase in the cost of the power supply protection circuit for integrated circuits.

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