Voltage Detection Circuit With Dual-Buffer Self-Diagnosis
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Solution Overview
Problem
Conventional voltage detection circuits fail to detect abnormalities in buffer circuits connected between voltage-dividing resistors and microcomputers, limiting comprehensive failure diagnosis capabilities.
Innovation Solution
A voltage detection circuit with a first and second buffer circuit, a voltage detection unit, a reference voltage output circuit, and a switch circuit that switches input voltages to reference voltages, enabling comprehensive abnormality diagnosis by comparing actual and expected voltage values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage-dividing resistors are used to detect high-voltage battery voltage, then voltage detection is enabled, but buffer circuit abnormalities cannot be detected
Solution Approach 1:
The invention applies preliminary action by performing self-diagnosis of the buffer circuit using the operational amplifier's own characteristics. The abnormality detection unit detects failures before they affect voltage measurement accuracy, by monitoring the open-loop voltage amplification characteristic of the operational amplifier in advance.
Solution Approach 2:
The voltage detection circuit performs self-service through automatic self-diagnosis. The buffer circuit uses its own operational amplifier to detect abnormalities in itself, without requiring external diagnostic equipment. The system monitors its own health status by detecting the open-loop voltage amplification characteristic.
2Ease of operation
If conventional voltage detection circuit is used, then voltage measurement is achieved, but comprehensive abnormality diagnosis is limited
Solution Approach 1:
The invention applies universality by making the voltage detection circuit multi-functional. The buffer circuit not only performs voltage measurement but also performs self-diagnosis of abnormalities. The operational amplifier serves dual purposes: voltage buffering and failure detection, eliminating the need for separate diagnostic circuits.
Solution Approach 2:
The invention applies feedback by implementing a self-diagnosis mechanism where the abnormality detection unit continuously monitors the buffer circuit's operational characteristics and provides feedback about its health status. The system uses the relationship between input and output voltages to detect abnormalities and can signal when the buffer circuit requires attention.
Data Source
AI summary
A voltage detection circuit includes a first buffer circuit and second buffer circuit that output a voltage corresponding to an input voltage, a voltage detection unit that detects an output voltage from the first buffer circuit and an output voltage from the second buffer circuit, a reference voltage output circuit capable of selectively outputting one of a plurality of reference voltages different in voltage value from each other, and a switch circuit connected to the first buffer circuit and second buffer circuit. The switch circuit switches an input voltage to the first buffer circuit, from a first input voltage corresponding to a voltage of a first input terminal connected to a measurement target to the reference voltage outputted from the reference voltage output circuit, and switches an input voltage to the second buffer circuit, from a second input voltage to the reference voltage outputted from the reference voltage output circuit.