Watchdog circuit for automobile electronic controller

Abstract

The invention discloses a watchdog circuit for an automobile electronic controller. The watchdog circuit for the automobile electronic controller comprises a power supply module which is used for supplying power to a power amplifying module, a voltage monitoring module and a signal output module; the power amplifying module is used for receiving a PWM (Pulse-Width Modulation) signal which is output by a single chip microcomputer, amplifying the power of the PWM signal, and outputting the power-amplified PWM signal to a square wave detecting module; the square wave detecting module is used for detecting the PWM signal; the voltage monitoring module is used for detecting a voltage signal which is output by the power supply module; the signal output module is used for receiving level signals which are output by the square wave detecting module and the voltage monitoring module, and outputting different alarm signals, resetting signals and limping mode enable signals to the single chip microcomputer according to the different level signals. According to the watchdog circuit for the automobile electronic controller, the hardware watchdog circuit is formed by adopting discrete devices; the alarm signals and the resetting signals can be generated and a limping mode can be started when a program of a microprocessor is abnormal, and the functional safety requirement of the automobile electronic controller is met.

Description

technical field [0001] The invention belongs to the technical field of automobile electronic controllers, and in particular relates to a watchdog circuit used for automobile electronic controllers. Background technique [0002] Automobile safety has always been the goal that people pursue unremittingly. In order to improve the safety of automobiles, more and more intelligent electronic controllers are applied to automobiles. These electronic controllers have functions of fault diagnosis, fault detection, fault warning, and failure protection. , Fault automatic recovery and fault automatic enable limp mode and other functions, usually the watchdog (also known as watchdog) circuit is the basic module to realize these functions. Generally, there is a software watchdog function inside the microprocessor (single-chip microcomputer or DSP, etc.), which can automatically return to normal when the microprocessor is slightly disturbed. If the disturbance is serious, it may cause the ...

AI Technical Summary

Problems solved by technology

[0003] The existing hardware watchdog circuit is mainly a solution for microprocessor programs running away or crashing, and most of them are realized by using a watchdog reset chip, which has the following three disadvantages: 1. The implementation cost is high, and the function Not flexible enough, and watchdog reset chips rarely meet the requirements of automotive applications

2. Only monitor the program running status of the microprocessor, not the voltage of the power supply

3. Only the function of reset output, no function of abnormal alarm and automatic activation of limp mode

These deficiencies are not conducive to the realization of safety functions of automotive electronic controllers, and increase the hidden dangers of driving safety.

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