Multi-Level Gate Turn-Off Circuit for Over-Current Protection
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Solution Overview
Problem
High-voltage and high-current applications require efficient power electronic devices capable of operating at elevated temperatures, but existing technologies fail to control power device turn-off in a controlled manner during over-current conditions, leading to high voltage overshoot spikes and potential device damage.
Innovation Solution
A multi-level turn-off circuit that includes an output high driver, an output low driver, and a clamp circuit to gradually reduce the gate voltage of power devices in multiple stages when an over-current condition is detected, ensuring controlled turn-off and minimizing surge current spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power device is turned off during over-current condition, then the over-current is interrupted, but high voltage overshoot spikes are generated causing potential device damage
Solution Approach 1:
The gate voltage reduction is divided into multiple discrete levels (first level, second level, third level) rather than a single abrupt change. Each level corresponds to a specific voltage threshold that triggers the next stage of turn-off, segmenting the protection process into controlled steps that prevent voltage overshoot while effectively interrupting over-current
Solution Approach 2:
The circuit performs preliminary detection of over-current conditions through current sensing before the fault fully develops. The multi-level turn-off circuit is pre-configured with voltage thresholds and sensing circuits that activate automatically when over-current is detected, enabling preventive action before damage occurs
2Speed
If gate voltage is reduced abruptly to turn off power device, then turn-off speed is fast, but surge current spikes occur causing device stress
Solution Approach 1:
The gate voltage reduction is divided into multiple discrete levels (first level, second level, third level) rather than a single abrupt change. Each level corresponds to a specific voltage threshold that triggers the next stage of turn-off, segmenting the protection process into controlled steps that prevent voltage overshoot while effectively interrupting over-current
Solution Approach 2:
The turn-off process dynamically adapts to the specific over-current condition by transitioning through different voltage levels based on real-time circuit state. The circuit automatically adjusts the turn-off aggressiveness by moving between levels, making the protection response dynamic rather than static
3Object-affected harmful factors
If multi-level turn-off circuit is implemented, then voltage overshoot is mitigated, but device complexity increases
Solution Approach 1:
The multi-level turn-off functionality is merged into a single integrated circuit that combines current sensing, voltage threshold detection, and multi-stage gate control. By merging these functions into one unified device, the patent reduces the overall system complexity compared to using separate discrete components for each function
Solution Approach 2:
The turn-off circuit is designed to perform multiple functions: over-current detection, multi-level voltage control, and adaptive turn-off. This universal circuit can handle different over-current scenarios and power device types, reducing the need for multiple specialized circuits
Data Source
AI summary
Methods, apparatus, systems, and articles of manufacture are disclosed for a multi-level turn-off circuit. An example power delivery circuit includes a two-level turn-off circuit to be coupled to a first switch to reduce a first gate voltage of the first switch from a first voltage to a second voltage when a current flowing through the first switch is greater than an over-current threshold, the two-level turn-off circuit including a second switch, a voltage-current-voltage buffer to reduce a second gate voltage of the second switch from a third voltage to a fourth voltage, and a comparator circuit to turn off the second switch when the second gate voltage is the fourth voltage, and a driver to be coupled to the first switch to turn off the first switch when the second gate voltage is the fourth voltage.