Charge Pump Gate Driver for Low Voltage DC/DC Converters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Switching regulators face challenges in effectively operating at low supply voltages, particularly in battery-powered systems, where it is difficult to turn on power transistors due to limited gate driver voltage, leading to high on-resistance and inefficiency.
Innovation Solution
Incorporating a charge pump and bootstrap capacitor configuration that provides a higher gate-to-source voltage for the high-side transistor, utilizing a clock with dual phases to manage switching and charge redistribution across capacitors, allowing for increased voltage boosting and reduced on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bootstrap capacitor is used to provide higher gate driver voltage at low supply voltages, then the gate-to-source voltage is improved, but the device complexity increases
Solution Approach 1:
The charge pump circuit is nested within the gate driver structure, with the bootstrap capacitor serving dual purposes: traditional voltage boosting and charge pump operation. The charge pump capacitors are integrated into the existing bootstrap capacitor, eliminating the need for separate components and reducing overall device complexity while maintaining improved gate-to-source voltage.
Solution Approach 2:
The bootstrap capacitor is designed to serve multiple functions: traditional voltage boosting for the gate driver and charge pump operation for additional voltage multiplication. This multi-functionality allows the system to achieve higher gate-to-source voltage without adding separate dedicated components, thereby improving performance while controlling complexity.
2Loss of energy
If a charge pump is added to provide higher gate-to-source voltage, then efficiency is improved, but device complexity increases
Solution Approach 1:
The charge pump circuit is merged with the gate driver structure, sharing common components such as the bootstrap capacitor and control logic. This integration combines the functions of voltage boosting and charge pumping into a unified circuit, achieving improved efficiency while minimizing the increase in device complexity through component sharing and functional consolidation.
3Strength
If multiple capacitors are used in the charge pump, then voltage boosting is improved, but device complexity increases
Solution Approach 1:
The charge pump capacitors are nested within the bootstrap capacitor structure, with smaller capacitors integrated into the larger bootstrap capacitor. This nesting arrangement achieves multiple stages of voltage boosting through cascaded capacitor networks while utilizing shared physical space and control mechanisms, thereby improving voltage boosting capability without proportionally increasing device complexity.
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 configuration enhances the gate-to-source voltage of the high-side transistor, improving efficiency and reducing on-resistance, even at low input voltages, thereby enhancing the performance of switching converters in battery-powered applications.
Implementation Method 1
The charge pump includes a first switch connected between the charge pump input and the first capacitor, a second switch connected between the first capacitor and the second capacitor, a third switch connected between the second capacitor and the third capacitor and a fourth switched connected between the third capacitor and the output of the change pump
Implementation Method 2
a bootstrap capacitor connected between the first voltage supply input and the second voltage supply input; the bootstrap capacitor is charged while the gate driver is off and discharged when the gate driver is turned on
Data Source
AI summary
A switching converter having a voltage input, a voltage output and a transistor connected between the voltage input and the voltage output, the switching converter including a control circuit comprising: a gate driver having an input, a first voltage supply input, a second voltage supply input and an output operable to be connected to a control terminal of the transistor; a bootstrap capacitor connected between the first voltage supply input and the second voltage supply input; and a charge pump having an input operable to be connected to the voltage input and an output connected to the first voltage supply input.