Power Switch Gate Discharge Control for Voltage Spike Suppression
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Solution Overview
Problem
Rapidly turning off a power switch under large output and input currents generates voltage spikes, leading to damage of peripheral components and electromagnetic interference in electronic devices.
Innovation Solution
A control device for a power switch that uses a discharge current generator to combine ramp and constant currents during the off procedure, rapidly discharging the control end in a first sub-time period and then transitioning to a constant current discharge in a second sub-time period to reduce voltage spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the power switch is rapidly turned off under large output and input currents, then the turn-off speed is improved, but voltage spikes are generated causing damage to peripheral components and electromagnetic interference
Solution Approach 1:
The turn-off process is divided into two distinct phases: a first turn-off phase with a first turn-off rate and a second turn-off phase with a second turn-off rate. This segmentation allows the system to achieve both rapid initial turn-off and controlled voltage spike reduction, resolving the contradiction between speed and harmful voltage generation
Solution Approach 2:
The turn-off rate is made dynamic by adjusting it according to the operating state of the power switch. The control device determines whether to apply the first or second turn-off rate based on real-time conditions, enabling adaptive control that optimizes both switching speed and voltage spike suppression
2Productivity
If the power switch is rapidly turned off, then the working efficiency is improved, but peripheral passive components or power components may be damaged
Solution Approach 1:
The turn-off procedure is segmented into two phases with different turn-off rates. The first phase maintains high speed for efficiency, while the second phase reduces the turn-off rate to protect components, thus resolving the contradiction between productivity and reliability
Solution Approach 2:
The turn-off rate parameter is dynamically changed based on the power switch's operating state. By adjusting this parameter from a first turn-off rate to a second turn-off rate, the system achieves both high working efficiency and component protection
Data Source
AI summary
A control device of a power switch includes a discharge current generator. The discharge current generator is coupled between a control end of the power switch and a reference voltage. In a time period when the power switch is turned off, the discharge current generator combines a first current and a second current in a first sub-time period to generate a third current and sets the control end of the power switch to be discharged according to the third current. The discharge current generator merely provides the second current in a second sub-time period and sets the control end of the power switch to be discharged according to the second current. The third current is greater than the second current. The first current decreases with time in the first sub-time period. The second current is a constant current.