Switched-Capacitor Gate Driver Circuits for Faster Power Switching
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Solution Overview
Problem
Existing driver circuits for power switches face challenges in reducing transition times and associated power losses during switching operations, as they often rely on hard switching due to limitations in component size and reactance required for soft switching, and high driving voltages are not always feasible.
Innovation Solution
The implementation of switched capacitor charge pumps in driver circuits to facilitate faster turn-on and turn-off transitions by providing boosted voltages for charging and discharging the gate of power switches, reducing the transition times and power losses without the need for larger driver transistors or higher driving voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If switched capacitor charge pumps are used to reduce transition times, then switching speed is improved, but device complexity increases
Solution Approach 1:
The driver circuit is segmented into multiple functional blocks: a first switched capacitor circuit for turn-on transitions, a second switched capacitor circuit for turn-off transitions, and a totem-pole output stage. Each segment handles a specific aspect of the switching operation, allowing the complex function of fast switching to be divided into manageable, specialized components that can be optimized independently.
Solution Approach 2:
The circuit employs dynamic voltage boosting through the switched capacitor charge pumps, where the voltage levels are dynamically adjusted during switching transitions. The first charge pump boosts voltage for rapid turn-on, while the second charge pump provides negative voltage for fast turn-off, creating a dynamic driving capability that adapts to the instantaneous needs of the power switch transitions.
2Speed
If larger driver transistors are used to reduce transition times, then switching speed is improved, but power consumption increases
Solution Approach 1:
Instead of changing the size of driver transistors, the invention changes the voltage parameter dynamically during switching. The switched capacitor charge pumps temporarily boost the driving voltage above normal operating levels during transitions, enabling faster switching without requiring larger transistors. This parameter change approach achieves speed improvement while maintaining normal power consumption levels during steady-state operation.
3Speed
If higher driving voltages are used to reduce transition times, then switching speed is improved, but circuit feasibility is reduced
Solution Approach 1:
The switched capacitor charge pumps operate periodically, boosting voltage only during the brief moments when switching transitions are required. The first charge pump periodically boosts voltage for turn-on events, and the second charge pump periodically provides negative voltage for turn-off events. This periodic action enables high-voltage driving capability on-demand without requiring the entire circuit to operate at higher voltage levels, maintaining feasibility for standard voltage systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of switched capacitor charge pumps significantly reduces both turn-on and turn-off transition intervals and associated power losses, enhancing the efficiency of power switch operations by enabling faster charging and discharging of the gate capacitance.
Implementation Method 1
a first switched capacitor charge pump arranged to provide a first boosted voltage for facilitating turning off the power switch, wherein the first switched capacitor charge pump includes a first capacitor arranged to store a first charge
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
Driver circuits are provided for driving a power switch. The driver circuits include one or more charge pumps configured to generate a boosted positive voltage and/or a decreased voltage to a gate of the power switch. The decreased voltage may provide a negative voltage to the gate of the power switch, relative to its source, when the power switch is transitioned to its off state. The boosted positive voltage provides a voltage that is higher than the voltage that would otherwise be provided by a driver power supply. The decreased voltage generated by a turn-off charge pump has the effect of transitioning the power switch to its off state more quickly. The boosted voltage generated by a turn-on charge pump has the effect of transitioning the power switch to its on state more quickly. The decreased transition times provided by the driver circuits reduce switching losses of the power switch.