Switched-Capacitor Gate Driver Power Supply With Fewer High-Voltage Devices
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Solution Overview
Problem
Switched-capacitor power converters face inefficiencies due to the need for high-voltage transistors and increased complexity as conversion gain increases, with existing gate drivers consuming significant power and requiring multiple types of devices, leading to high fabrication costs.
Innovation Solution
The implementation of a controller-driven apparatus with gate drivers powered by capacitors, using low-voltage transistors and resistor dividers to manage gate-to-source voltages efficiently, and cascaded gate drivers to support higher voltages while minimizing the number of high-voltage devices, allowing for efficient operation and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-voltage transistors are used in switched-capacitor converters, then the converter can operate at higher voltages, but the fabrication cost increases and device complexity increases
Solution Approach 1:
The gate driver is divided into multiple stages: a low-voltage stage that operates on the input voltage and a high-voltage stage that generates the required high gate voltages. This segmentation allows low-voltage transistors to be used in the majority of the circuit while only requiring high-voltage transistors in the specific high-voltage generation stage, thereby reducing overall device complexity and fabrication cost while maintaining high-voltage operating capability
Solution Approach 2:
A capacitor is introduced as an intermediary energy storage element between the low-voltage input and the high-voltage gate drive requirements. The capacitor is charged from the low-voltage input and then used to generate the necessary high-voltage pulses for gate driving, acting as a mediator that eliminates the need for high-voltage transistors in the main power switching path
2Ease of operation
If conventional gate drivers are used, then switches can be driven properly, but significant power is consumed and multiple types of devices are required
Solution Approach 1:
The gate driver circuit is designed to draw its operating power directly from the capacitors it is driving, rather than from a separate power supply. The capacitors discharge through the gate driver transistors, and this discharge current is reused to power the gate driver circuitry itself, creating a self-service system that minimizes additional power consumption while maintaining proper switch driving capability
Solution Approach 2:
The circuit recovers energy from the capacitors during their discharge phase and reuses it to power the gate driver. Instead of allowing the capacitor discharge energy to be wasted, the gate driver is configured to capture and utilize this energy, thereby reducing overall power consumption while maintaining the necessary voltage levels for switch operation
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 approach enhances the efficiency of switched-capacitor power converters by reducing the charge deposited and discharged from transistor gates, enabling the use of low-voltage transistors and minimizing the number of high-voltage devices, thereby reducing fabrication costs and improving overall converter performance.
Implementation Method 1
first and second capacitors in a switched-capacitor network that is coupled to the switches
Implementation Method 2
resistor dividers to manage gate-to-source voltages efficiently
Data Source
AI summary
An apparatus includes first and second pluralities of switches, a controller for controlling these switches, gate-drivers for driving switches from the first plurality of switches, and first and second terminals configured for coupling to corresponding first and second external circuits at corresponding first and second voltages. During operation, the controller causes the first plurality of switches to transition between states. These transitions result in the second voltage being maintained at a value that is a multiple of the first voltage. The controller also causes the second plurality of switches to transition between states. These transitions resulting in capacitors being coupled or decoupled from the second voltage. The gate drivers derive, from the capacitors, charge for causing a voltage that enables switches from the first plurality of switches to be driven.