Switched Capacitor Flyback Converter for Wide Output Voltage Efficiency
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Solution Overview
Problem
Conventional flyback power converters face inefficiencies due to the broad range of output voltage levels, which results in primary and secondary side control circuits operating over a wide voltage range, leading to poor efficiency.
Innovation Solution
A switched capacitor converter circuit that adjusts the power supply voltage by switching the coupling configurations of conversion and output capacitors based on the input voltage level, providing a controlled power supply to the power converter circuit, thereby reducing the voltage range and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the output voltage range is expanded to cover multiple applications (3.2V to 48V), then the versatility of the power converter is improved, but the auxiliary voltage range becomes too broad causing poor efficiency
Solution Approach 1:
The auxiliary voltage regulation function is segmented into two stages: the switched capacitor converter handles coarse voltage adjustment in wide ranges, while the linear regulator handles fine voltage adjustment near the target value. This segmentation allows each stage to operate in its optimal efficiency range, resolving the contradiction between wide voltage adaptability and power efficiency.
Solution Approach 2:
The switched capacitor converter acts as an intermediary stage between the broad-range auxiliary voltage and the narrow-range linear regulator input. It bridges the gap by providing intermediate voltage levels that are suitable for the linear regulator, enabling the system to maintain high efficiency across the full 3.2V to 48V output voltage range.
2Adaptability or versatility
If the auxiliary voltage range is broad to support multiple output voltage levels, then the adaptability is improved, but the control circuit operation efficiency deteriorates
Solution Approach 1:
The voltage regulation function is segmented between the switched capacitor converter (coarse adjustment) and linear regulator (fine adjustment). This allows the control circuit to operate efficiently by having the switched capacitor converter handle the broad voltage range initially, then transitioning to the linear regulator for precise control near the target voltage.
Solution Approach 2:
The switched capacitor converter performs preliminary voltage adjustment before the linear regulator takes over. By pre-adjusting the auxiliary voltage to a level close to the target using the switched capacitor converter, the linear regulator only needs to make minor adjustments, significantly improving overall control circuit efficiency.
3Adaptability or versatility
If the primary side control circuit and secondary side control circuit operate in very broad voltage range, then the versatility is improved, but the power efficiency deteriorates
Solution Approach 1:
The power consumption issue is addressed by segmenting the voltage regulation into two stages: the switched capacitor converter handles broad voltage range adjustment with high efficiency, while the linear regulator handles narrow-range fine-tuning. This segmentation ensures that neither circuit operates inefficiently across the entire broad voltage range.
Solution Approach 2:
The system dynamically switches between the switched capacitor converter and linear regulator based on the auxiliary voltage level. When the auxiliary voltage is far from the target, the switched capacitor converter is active; when it approaches the target, the linear regulator takes over. This dynamic operation optimizes power consumption across all voltage conditions.
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 reduces the required withstand voltages and power consumption of control circuits while improving the power efficiency of the primary and secondary side control circuits.
Implementation Method 1
a conversion capacitor CF and an output capacitor Co. The switches S1-S5 are configured to operably switch the coupling configurations of the conversion capacitor CF and the output capacitor Co
Implementation Method 2
a transformer 10 generates an auxiliary voltage VNA... A secondary winding NS of the transformer 10 generates an output voltage Vout
Data Source
AI summary
A switched capacitor converter circuit includes: a conversion capacitor; an output capacitor; and switches configured to switch the coupling configurations of the conversion capacitor and the output capacitor according to a level of the first power supply voltage of the switched capacitor converter circuit, to generate the second power supply voltage at the output capacitor according to the first power supply voltage. The second power supply voltage provides power to control the power converter circuit. When the first power supply voltage is higher than a high threshold, the switched capacitor converter circuit controls the second power supply voltage to be lower than the first power supply voltage. When the first power supply voltage is lower than a low threshold, the switched capacitor converter circuit controls the second power supply voltage to be higher than the first power supply voltage.