Self-Oscillating Charge Pump for High Side Driver Boost Voltage
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Solution Overview
Problem
In power supply systems, the boost voltage often decreases during periods of non-switching of transistors, leading to inefficient operation due to the lack of power supply for the high side driver during burst mode or cycle-skipping periods.
Innovation Solution
A self-oscillating charge pump circuit is introduced to charge a pump capacitor to a specific voltage and transfer charge to a boost capacitor independently of the switching periods of the transistors, ensuring continuous power supply to the high side driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bootstrap circuit is used to generate boost voltage for the high side driver, then the high side driver can be powered during normal switching operation, but the boost voltage decreases during non-switching periods (burst mode or cycle-skipping) causing inefficient operation
Solution Approach 1:
The power supply system is segmented into two independent charging paths: the traditional bootstrap circuit for normal operation and a new dedicated charging circuit for burst mode. This segmentation allows each circuit to be optimized for its specific operating condition without interfering with the other, resolving the contradiction between reliability during switching and efficiency during non-switching periods.
Solution Approach 2:
The dedicated charging circuit pre-charges the bootstrap capacitor during non-switching periods before burst mode begins. This preliminary action ensures that sufficient boost voltage is available immediately when switching resumes, eliminating the delay and voltage drop that previously occurred during burst mode transitions.
2Loss of energy
If the power switches are not switched for extended periods (burst mode), then energy consumption is reduced, but the boost voltage decreases causing the high side driver to lose power supply
Solution Approach 1:
The dedicated charging circuit automatically activates during burst mode to recharge the bootstrap capacitor without requiring external intervention or complex control logic. The circuit self-regulates based on the voltage level detection, providing seamless power maintenance during energy-saving periods while ensuring reliability when needed.
3Device complexity
If a traditional bootstrap circuit is used, then the circuit structure is simple, but it cannot maintain boost voltage during non-switching periods leading to inefficient operation
Solution Approach 1:
The solution merges the traditional bootstrap circuit with a dedicated charging circuit into a hybrid power supply system. The bootstrap circuit handles normal switching operation while the dedicated charging circuit supplements power during burst mode, combining the simplicity of the original design with the efficiency benefits of the additional circuit.
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 maintains the boost voltage level even during non-switching periods, enhancing the efficiency and reliability of the power supply system by providing power to the high side driver when needed, thus preventing inefficient operation.
Implementation Method 1
A self-oscillating charge pump circuit is introduced to charge a pump capacitor to a specific voltage and transfer charge to a boost capacitor independently of the switching periods of the transistors
Data Source
AI summary
In one embodiment, a charge pump circuit is used to keep a boost capacitor of a power supply system charged while the switch transistors are not switching such as when the power supply system is operating in a burst mode of operation.