Integrated Clamp Circuit for Fast-Switching Transistor Overvoltage
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Solution Overview
Problem
Power transistor devices are vulnerable to voltage spikes during transitions, which can exceed their voltage blocking capability, potentially damaging the device and increasing conduction losses and costs as the voltage blocking capability is enhanced to mitigate this.
Innovation Solution
An electronic circuit with a clamping circuit that includes a second transistor device connected in parallel with the first transistor device, driven by a drive circuit with a clamping element and resistor, which prevents voltage spikes by switching on the second transistor device to divert current and protect the first transistor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage blocking capability of the transistor device is increased to withstand voltage spikes, then the reliability of the transistor device is improved, but the conduction losses and manufacturing cost increase
Solution Approach 1:
A clamping circuit is introduced as an intermediary protective mechanism between the transistor device and the voltage spikes. The clamping circuit includes a second transistor device and a clamp element that activate during voltage spike events to limit the voltage across the first transistor device, allowing the first transistor device to operate with lower voltage blocking capability while maintaining reliability
Solution Approach 2:
The clamping circuit is pre-configured and integrated with the first transistor device before operation. The clamp element and second transistor device are prepared in advance to quickly respond to voltage spikes, enabling the first transistor device to be designed with optimized (lower) voltage blocking capability while still being protected against overvoltage events
2Productivity
If the transistor device switches faster from on-state to off-state to improve productivity, then the productivity is improved, but the voltage spikes increase which may destroy the transistor device
Solution Approach 1:
The clamping circuit acts as a protective intermediary that absorbs and limits voltage spikes generated during fast switching events. The second transistor device and clamp element provide a controlled path for spike energy, enabling the first transistor device to switch at high speeds without being damaged by the resulting voltage transients
Solution Approach 2:
The clamping circuit is designed to provide protective cushioning against voltage spikes before they can damage the transistor device. The circuit is pre-positioned and configured to immediately clamp voltage excursions during switching transitions, cushioning the first transistor device from the harmful effects of fast switching
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
An electronic circuit and a method are disclosed. The electronic circuit includes: a first transistor device (1) having a load path between a first load path node (11) and a second load path node (12); and a clamping circuit (6) connected to the load path of the first transistor device (1). The clamping circuit (6) includes: a second transistor device (2) having a load path connected in parallel with the load path of the first transistor device (1), and a control node (23); and a drive circuit (3) configured to drive the second transistor device (2). The drive circuit (3) includes a clamping element (4) and a resistor (5) connected in series between the first and second load path nodes (11, 12) of the first transistor device (1). The drive circuit (3) is configured to drive the second transistor device (2) dependent on a voltage (V5) across the resistor (5), and the first transistor device (1) and the clamping circuit (6) are integrated in the same semiconductor die (100).