High-Side Gate Driver Using Super Source Follower for Transient Response
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Solution Overview
Problem
Switching converters face challenges in high-side gate driving due to the burden of high current requirements, which increases complexity and reduces performance, especially when exceeding the gate-to-source voltage rating of semiconductor switches, leading to potential device damage and decreased transient response.
Innovation Solution
The implementation of a super source follower circuit coupled with a mid-voltage power supply in the gate driving circuit for high-side switches, reducing current flow through the mid-voltage power supply and eliminating the need for large capacitors, thereby simplifying the design and improving transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a floating voltage rail is used to reduce gate-to-source voltage, then device safety is improved, but circuit complexity and area increase
Solution Approach 1:
The patent extracts the voltage reduction function from a complex floating voltage rail system and implements it through a simpler resistor divider network. The resistor divider takes out only the essential voltage scaling function, eliminating unnecessary circuit complexity while maintaining device safety through proper gate voltage control.
Solution Approach 2:
The patent introduces an intermediary resistor divider circuit between the power supply and the gate terminal. This intermediary structure mediates the voltage level, providing the necessary gate-to-source voltage reduction without requiring a complex floating voltage rail, thus simplifying the overall circuit while protecting the device.
2Ease of operation
If a floating voltage rail is used to control gate voltage, then voltage control is improved, but impedance increases and transient response decreases
Solution Approach 1:
The patent extracts the essential voltage control function from the floating voltage rail and implements it through a resistor divider network with direct ground reference. This extraction eliminates the high-impedance floating rail while maintaining effective gate voltage control, thereby improving transient response speed.
Solution Approach 2:
The patent establishes an equipotential reference by grounding one side of the resistor divider, creating a stable voltage reference point. This equipotential configuration reduces impedance compared to floating rails while maintaining precise gate voltage control, enabling faster transient response.
3Power
If mid-voltage power supply is used with super source follower, then current burden is reduced, but circuit complexity increases
Solution Approach 1:
The patent introduces a super source follower circuit as an intermediary stage between the mid-voltage power supply and the gate terminal. This intermediary actively drives the gate, reducing the current burden on the power supply while the associated capacitor provides necessary charge storage, achieving a balance between power reduction and controlled complexity.
Solution Approach 2:
The patent implements preliminary action by pre-charging the gate through the super source follower and associated capacitor before switching events. This preliminary charging reduces the instantaneous current demand on the power supply during transient events, effectively reducing the current burden while using a relatively simple circuit configuration.
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
This solution effectively clamps the gate voltage of high-side switches, reducing current through the mid-voltage power supply, decreasing complexity and cost, and enhancing the transient response of switching converters by minimizing impedance and parasitic capacitance.
Implementation Method 1
This solution effectively clamps the gate voltage of high-side switches
Implementation Method 2
reducing current flow through the mid-voltage power supply and eliminating the need for large capacitors
Data Source
AI summary
Techniques for improving the transient response in a switching converter are provided. An example of a gate driving circuit for driving a high-side switch in a switching converter according to the disclosure includes a first switch operably coupled to a source lead and a gate lead of the high-side switch, a first super source follower circuit operably coupled to the gate lead of the high-side switch, and a mid-voltage power supply operably coupled to the first super source follower circuit.