Power-off timing circuit of automotive control unit

Abstract

A power-off timing circuit of an automotive control unit is applicable to control circuits of automotive electronic control units, and comprises two digital control ports of a single chip microcomputer, an analog-to-digital conversion input port and semiconductor components such as a composite triode, a field-effect transistor, capacitors and resistors and the like. The capacitors and the resistors form a charge-discharge circuit, the composite triode and the field-effect transistor form an on-off circuit, on-off control logic of the on-off circuit can be realized by the single chip microcomputer according to actual needs, the analog-to-digital conversion input port is used for detecting voltage values of two ends of one capacitor, judging power-off time according to detection results of the voltage, and then selecting action of the single chip microcomputer according to a power-off time threshold value set by a user. The power-off timing circuit of the automotive control unit is convenient in timing time adjustment, simple in control and judgment and less in occupancy of single chip microcomputer resources, damage of high voltage to the single chip microcomputer can be prevented by means of features of the field-effect transistor in the on-off circuit, the circuits are simple, and cost is reduced.

Description

Technical field: [0001] The invention relates to the field of electricity, in particular to a timing circuit, especially a power-off timing circuit of an automobile control unit. Background technique: [0002] The electronic control unit in the car saves status data when the power is connected. After the power is disconnected, the status data is either saved forever or never. After the electronic control unit is powered on and initialized again, the status data needs to be reset. For testing or maintenance purposes, it is sometimes necessary to briefly disconnect the power supply to the ECU. In addition, when a car with start / stop function is restarted, the car power supply voltage may appear an abnormal voltage that is close to power-off for about 10 seconds. In the prior art, in order to meet the requirement that the status data at the time of power failure can still be kept in the case of short-term power failure, but not saved for a long time, a real-time clock circuit ...

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to provide a kind of power-off timing circuit of automobile control unit, and the power-off timing circuit of this kind of automobile control unit should solve the complex and high cost of timing circuit after power-off of automobile electronic control unit in the prior art technical issues

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