Transistor Bridge Short-Circuit Detection via Preliminary Test Current
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Solution Overview
Problem
Existing driver circuits for transistor bridges are inadequate in detecting short-circuits and open-circuits efficiently, leading to potential damage from current spikes and a lack of timely protection mechanisms, especially when driving electric motors.
Innovation Solution
A driver circuit arrangement that includes a current source and detection circuit to supply a test current to the transistor bridge, allowing for the detection of short-circuits by comparing a voltage sense signal across the high-side transistor with predefined thresholds, enabling early fault detection and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transistor bridge is activated to detect over-currents, then the short-circuit can be detected, but current spikes may damage the system before detection
Solution Approach 1:
The patent applies preliminary action by performing a test current supply through the high-side transistor before normal operation to detect short-circuits in advance. The detection circuit measures the voltage across the high-side transistor while it is switched on during a test phase, allowing short-circuit detection before the transistor bridge is fully activated and before harmful current spikes can occur during normal operation.
2Loss of information
If the transistor bridge is activated for short-circuit detection, then fault information is obtained, but the protection mechanism is too slow
Solution Approach 1:
The patent implements preliminary action by conducting short-circuit detection during a test phase before normal operation begins. The detection circuit is activated together with the high-side transistor during this preliminary test phase, enabling immediate detection of short-circuits before the transistor bridge enters normal operation mode, thus eliminating protection delays.
3Reliability
If a test current is supplied through the high-side transistor, then short-circuit detection is enabled, but additional circuit complexity is introduced
Solution Approach 1:
The patent applies universality by designing the detection circuit to serve multiple functions: it detects both short-circuits and open-circuits using the same basic circuitry. The detection circuit can operate in different modes (test phase and normal operation phase) and uses the high-side transistor's voltage measurement capability for multiple detection purposes, reducing the need for separate dedicated circuits for each fault type.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables rapid and accurate detection of short-circuits and open-circuits, preventing damage and providing timely protection mechanisms, thus ensuring the reliability and safety of the transistor bridge and connected loads.
Implementation Method 1
supplying a test current to an output node of the first half-bridge and detecting, whether a short-circuit is present in the first half-bridge, by comparing a voltage sense signal, which represents the voltage across the high-side transistor
Data Source
AI summary
A driver circuit arrangement for driving a transistor bridge, which includes at least a first half-bridge composed of a low-side transistor and a high-side transistor, is described herein. In accordance with one example of the description, the circuit includes a current source and a detection circuit. The current source is operably coupled to the high-side transistor of the first half-bridge and configured to supply a test current to the first half bridge. The detection circuit is configured to compare a voltage sense signal, which represents the voltage across the high-side transistor of the first half-bridge, with at least one first threshold to detect, dependent on the result of this comparison, whether a short-circuit is present in the first half-bridge.