Variable Resistance Balance Resistor for Power Switching
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Solution Overview
Problem
The connection of a gate resistor with a relatively large resistance value in parallel-connected semiconductor switching devices increases turn-on and turn-off times, leading to undesired increases in turn-on and turn-off losses, and also fails to effectively suppress parasitic oscillation and radiation noise during switching operations.
Innovation Solution
A power switching apparatus with balance resistor units, each having a resistance value that can be switched between different values depending on the operation state, connected in parallel with semiconductor switching devices to suppress parasitic oscillation without increasing losses during turn-on or turn-off operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gate resistor with a relatively large resistance value is connected to suppress parasitic oscillation, then parasitic oscillation is suppressed, but turn-on time and turn-off time increase leading to increased turn-on loss and turn-off loss
Solution Approach 1:
The patent applies dynamics by making the gate resistor's resistance value variable rather than fixed. The resistance value is dynamically adjusted based on the switching state: a first resistance value is used during turn-off to suppress parasitic oscillation, while a second (smaller) resistance value is used during turn-on to reduce turn-on loss. This dynamic adjustment resolves the contradiction by optimizing the resistance value for each specific operational phase.
Solution Approach 2:
The patent implements parameter changes by varying the resistance value of the gate resistor according to the switching operation phase. The control circuit changes the resistance parameter from a first value (for turn-off suppression) to a second value (for turn-on efficiency), thereby adapting the system parameters to different operational requirements and eliminating the need to compromise between oscillation suppression and loss reduction.
2Object-affected harmful factors
If a gate resistor with a relatively large resistance value is added to reduce radiation noise, then radiation noise is suppressed, but turn-on loss and turn-off loss increase
Solution Approach 1:
The patent uses dynamics by adjusting the gate resistor's resistance value according to the specific operational requirement. During turn-off, a larger resistance value suppresses radiation noise and parasitic oscillation. During turn-on, a smaller resistance value is applied to minimize turn-on loss. This dynamic adaptation allows the system to suppress harmful effects only when necessary, without permanently degrading switching efficiency.
Solution Approach 2:
The control circuit changes the resistance parameter of the gate resistor based on the switching phase. By transitioning between a first resistance value (for noise suppression during turn-off) and a second resistance value (for efficient turn-on), the system optimizes both radiation noise suppression and energy efficiency, avoiding the compromise required by fixed resistance values.
Data Source
AI summary
A power switching apparatus includes a plurality of semiconductor switching devices connected in parallel with each other and a plurality of balance resistor units. The plurality of balance resistor units each have one end connected to a control electrode of an associated semiconductor switching device and the other end to which a common control signal is input. Each balance resistor unit is configured to have a resistance value switched between different values depending on whether the plurality of semiconductor switching devices are turned on or turned off in accordance with the control signal.