Driver Supply Voltage Generation Using Bootstrap and Boost Voltages
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Solution Overview
Problem
Existing power systems face challenges in providing a supply voltage with sufficient driving ability without increasing quiescent current or die size, particularly when the switching frequency of the charge pump circuit is low or the capacitance of the flying capacitor is small.
Innovation Solution
A power system design incorporating a switching circuit with high and low side transistors, a bootstrap capacitor, and a power generation circuit that generates a supply voltage using input, boost, and bootstrap voltages to enhance driving ability without increasing quiescent current or die size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the switching frequency of the charge pump circuit is increased to improve driving ability, then the driving ability is improved, but the quiescent current of the power system increases
Solution Approach 1:
The patent changes the voltage parameter by generating a supply voltage that is higher than the traditional charge pump output voltage. By using a power generation circuit that combines input voltage, boost voltage, and bootstrap voltage, the system achieves higher driving ability without increasing switching frequency, thus avoiding increased quiescent current.
2Power
If the capacitance of the flying capacitor is increased to improve driving ability, then the driving ability is improved, but the die size of the power system increases
Solution Approach 1:
The patent changes the voltage parameter instead of the capacitance parameter. By generating a higher supply voltage through the power generation circuit, the system achieves improved driving ability without increasing the capacitance of the flying capacitor, thus avoiding increased die size.
3Device complexity
If a traditional charge pump circuit is used to provide supply voltage, then the circuit structure is simple, but the driving ability is insufficient
Solution Approach 1:
The patent merges multiple voltage sources (input voltage, boost voltage, and bootstrap voltage) in the power generation circuit to create a supply voltage with sufficient driving ability. This combination approach maintains reasonable circuit complexity while achieving the required performance.
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 solution effectively increases the driving ability of the supply voltage without increasing quiescent current or die size, ensuring quick turn-on and turn-off of power switches.
Implementation Method 1
a bootstrap capacitor coupled between the switching node and a bootstrap terminal... The bootstrap capacitor is configured to provide a bootstrap voltage at the bootstrap terminal
Implementation Method 2
The switching circuit is configured to work in a buck mode to convert the input voltage to the system voltage, or to work in a boost mode to convert the system voltage to a boost output voltage
Data Source
AI summary
A supply voltage generating circuit and method for a power system. The power system has a power input terminal to receive an input voltage, a system output terminal to provide a system voltage, a switching circuit, a bootstrap capacitor, and a first driver circuit with a power terminal. The switching circuit works in a buck mode to convert the input voltage to the system voltage, or in a boost mode to convert the system voltage to a boost output voltage. The bootstrap capacitor provides a bootstrap voltage at a bootstrap terminal. The method is generating an input pump voltage based on the input voltage and the boost output voltage, generating a first supply voltage based on the bootstrap voltage and the input pump voltage, and providing the first supply voltage to the power terminal of the first driver circuit.