Switching Device Driving Circuit for Leakage Current Suppression
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Solution Overview
Problem
Power devices face challenges in reducing leakage current between control and output terminals of switching devices, leading to increased noise, malfunction, and power consumption, particularly at high voltages.
Innovation Solution
A driving circuit is implemented that delays the control signal and applies a driving voltage to the control terminal after a delay period, ensuring the voltage between the control and output terminals remains below a critical threshold, using a combination of delay cells, pull-up, and pull-down circuits, and voltage generation circuits to manage the rise time based on current-voltage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driving voltage is applied quickly to the control terminal, then the switching speed is improved, but leakage current increases between the control terminal and output terminal
Solution Approach 1:
The patent applies preliminary action by delaying the control signal before applying the driving voltage to the control terminal. The delay circuit introduces a time delay that ensures the output terminal voltage rises first, preventing excessive voltage difference that would cause leakage current. This preliminary timing adjustment resolves the contradiction by preparing the system state before the main action occurs.
Solution Approach 2:
The patent changes the time parameter by introducing a delay period and controlling the rise time of the driving voltage. By adjusting these temporal parameters, the voltage difference between control and output terminals is maintained below the critical threshold during the switching transition, thereby suppressing leakage current while still achieving fast switching operation.
2Object-generated harmful factors
If the voltage between control terminal and output terminal is kept low, then leakage current is reduced, but the rise time of driving voltage increases
Solution Approach 1:
The delay circuit performs preliminary action by advancing the timing of the output terminal voltage rise before the control terminal voltage is applied. This ensures that when the driving voltage is applied to the control terminal, the voltage difference remains within safe limits, preventing leakage current without requiring excessive delay that would significantly increase rise time.
Solution Approach 2:
The patent optimizes the temporal parameters by carefully controlling the delay period and rise time. The delay is set to the minimum necessary value to prevent leakage current, and the rise time is optimized to be as short as possible while maintaining the voltage difference below the critical threshold. This parameter optimization resolves the contradiction between reducing leakage current and minimizing time loss.
3Object-generated harmful factors
If a delay circuit is introduced to control the timing, then leakage current is suppressed, but the device complexity increases
Solution Approach 1:
The delay circuit acts as an intermediary element between the control signal source and the control terminal. This intermediary component introduces the necessary time delay to prevent leakage current without requiring fundamental changes to the switching device structure. The delay circuit mediates the timing relationship, resolving the contradiction by adding a relatively simple intermediate stage rather than complicating the main switching device.
Solution Approach 2:
Instead of adding complex control logic or multiple switching stages, the patent uses parameter changes in the timing domain. By adjusting the delay period and rise time parameters, the circuit achieves leakage current suppression with minimal added complexity. This approach is simpler than alternative solutions that would require additional active devices or complex control logic.
Data Source
AI summary
A power device includes a switching device having a control terminal and an output terminal; and a driving circuit configured to provide a driving voltage to the control terminal such that a voltage between the control terminal and the output terminal remains less than or equal to a critical voltage. A rise time required for the driving voltage to reach a target level is determined according to current-voltage characteristics of the switching device. And, when the voltage between the control terminal and the output terminal exceeds the critical voltage, leakage current is generated between the control terminal and the output terminal.