Abnormal H-Bridge Gate Voltage Detection Circuit
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Solution Overview
Problem
Existing motor driver systems face issues with abnormal conditions caused by failures in the bias supply circuit, leading to potential gate breakdown and overcurrent, which can result in motor breakdown.
Innovation Solution
A circuit device with a bridge circuit, pre-driver circuit, bias circuit, and abnormal condition detection circuit that detects high voltages between the gate and source of transistors and sets the gate-source voltage to a lower value, preventing or reducing abnormal conditions by using switch circuits and SR latch circuits to manage bias voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bias circuit is provided to supply bias voltage for setting the low level of drive signals, then proper gate-source voltage can be applied to transistors, but gate breakdown and overcurrent may occur if the bias circuit fails
Solution Approach 1:
The abnormal condition detection circuit proactively monitors the gate-source voltage before breakdown occurs. When an abnormal high voltage is detected, the circuit immediately clamps the gate voltage to a safe level, preventing gate breakdown and overcurrent before they can damage the transistor or motor
Solution Approach 2:
The abnormal condition detection circuit acts as an intermediary protective layer between the bias circuit and the transistor gate. It monitors the gate-source voltage and intervenes by clamping the voltage when abnormalities occur, isolating the transistor from harmful voltage conditions while maintaining normal operation during healthy bias supply
2Device complexity
If the bias circuit is simplified, then device complexity is reduced, but the risk of bias circuit failure causing abnormal conditions increases
Solution Approach 1:
The abnormal condition detection circuit provides self-protection functionality within the existing bias circuit architecture. Rather than requiring a completely redundant backup bias circuit, the detection circuit autonomously monitors and protects the transistor gate, enabling the system to tolerate bias circuit simplification while maintaining reliability through automatic abnormal voltage clamping
Data Source
AI summary
An electronic circuit includes a failure detection circuit that detects an abnormality of the gate potential of a transistor of a bridge circuit. The failure detection circuit monitors an output voltage of a drive circuit that is to be the gate potential of the transistor of the bridge circuit and, when detecting an abnormality, stops the drive circuit.