Variable-Current Gate Driver for Fast Switching With Lower Power
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Solution Overview
Problem
The existing gate driver circuits consume significant power due to constant current flow from the current source, leading to wasted energy and delays when the current source is turned off and on, which hinders high-speed operation.
Innovation Solution
A gate driver circuit with a variable current source that switches between two current levels, allowing the current distribution circuit to switch between source, sink, and disabled states to control gate voltage slew rates and reduce power consumption after transitions, enabling high-speed switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a constant current source is used to control gate voltage slew rates, then the rising and falling speeds of gate voltage can be controlled, but power consumption increases due to continuous current flow
Solution Approach 1:
The patent applies dynamics by making the current source variable rather than constant. The current source dynamically adjusts its output current between a first current level (during transitions) and a second current level (during steady state), allowing slew rate control when needed while minimizing power consumption during stable operation. This is achieved through control circuitry that monitors gate voltage transitions and modulates the current source accordingly.
Solution Approach 2:
The patent implements periodic action by activating the high current level only during the brief periods when gate voltage transitions are required, and switching to the low current level during the majority of operation time. This pulsed current delivery pattern maintains the necessary slew rate control capability while dramatically reducing average power consumption compared to continuous constant current flow.
2Use of energy by moving object
If the current source is turned off to reduce power consumption, then energy is saved, but delays occur when the current source needs to be turned on again
Solution Approach 1:
The patent applies preliminary action by keeping the current source in a standby state with the second (lower) current level continuously active or pre-charged. This preliminary state maintains the circuit components in readiness, so when a gate voltage transition is required, the current source can immediately switch to the first (higher) current level without significant delay. The preliminary standby current prevents the turn-on delay that would occur if the current source were completely shut off.
Solution Approach 2:
The patent utilizes parameter changes by switching the current source between two defined current levels (first current level and second current level) rather than between completely on and completely off states. This parameter switching approach allows the circuit to maintain operational readiness at the lower current level while still providing the higher current level when needed, eliminating the startup delay associated with transitioning from a zero-current state.
3Productivity
If high current levels are maintained continuously for fast switching, then switching speed is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the current source variable rather than constant. The current source dynamically adjusts its output current between a first current level (during transitions) and a second current level (during steady state), allowing slew rate control when needed while minimizing power consumption during stable operation. This is achieved through control circuitry that monitors gate voltage transitions and modulates the current source accordingly.
Solution Approach 2:
The patent applies partial action by using high current levels only for the brief duration necessary to complete gate voltage transitions, and low current levels for the remainder of the operation cycle. This partial application of high current achieves the necessary switching speed without the continuous energy waste of maintaining high current levels throughout the entire operating cycle.
Data Source
AI summary
A gate driver circuit drives a switching transistor. A variable current source generates a reference current configured to switch between a first current amount and a second current amount smaller than the first current amount. A current distribution circuit is configured to switch between a source enabled state in which a source current proportional to the reference current is sourced to a gate node of the switching transistor and a disabled state in which the source current is made equal to zero. A first transistor fixes the gate node of the switching transistor to a high voltage in an on-state of the first transistor. A second transistor fixes the gate node of the switching transistor to a low voltage in an on-state of the second transistor.