Charge-Pump Switching Power Supply Using Single Flying Capacitor
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Solution Overview
Problem
Existing compact-size information terminals, such as mobile phones and PDAs, face challenges in reducing size and cost due to the need for multiple external flying capacitors to generate both higher and negative voltages for load circuits, which increases the number of circuit components.
Innovation Solution
A switching power supply apparatus that uses a single flying capacitor and multiple output capacitors, controlled by a driver circuit, to generate multiple voltage levels, including inverted and doubled input voltages, using a simplified circuit configuration and time-division charging periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a booster circuit and a voltage inverter circuit are mounted respectively to supply voltage to load circuits requiring higher voltage and negative voltage, then the required voltage levels can be achieved, but the number of circuit components increases due to needing separate flying capacitors for each circuit
Solution Approach 1:
The patent merges the functions of a booster circuit and a voltage inverter circuit into a single integrated power supply apparatus. The flying capacitor is shared between both functions, and the driver circuit coordinates time-division control to achieve both voltage boosting and voltage inversion without requiring separate circuits or capacitors for each function.
Solution Approach 2:
The flying capacitor serves multiple functions: it acts as the flying capacitor for the booster circuit to generate higher positive voltage, and simultaneously serves as the flying capacitor for the voltage inverter circuit to generate negative voltage. The driver circuit enables this multi-functionality through time-division control, making the single capacitor universal for both voltage conversion tasks.
2Reliability
If external flying capacitors are provided for each power supply apparatus, then the required capacitance can be achieved, but the size of the terminal device increases
Solution Approach 1:
The patent reduces device size by merging the capacitance requirements of both the booster and voltage inverter circuits into a single flying capacitor. This eliminates the need for two separate external capacitor components, thereby reducing the overall device volume while maintaining the necessary capacitance performance for both functions through coordinated switching control.
3Reliability
If external flying capacitors are provided for each power supply apparatus, then the required capacitance can be achieved, but the cost of the terminal device increases
Solution Approach 1:
The patent reduces manufacturing cost by consolidating the capacitance requirements into a single flying capacitor that serves both the booster and voltage inverter functions. This reduction in component count directly lowers material costs, assembly costs, and testing costs, making the terminal device more cost-effective while maintaining reliable capacitance performance through efficient time-division control.
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 allows for the generation of multiple output voltages with reduced circuit complexity, minimizing the number of components and enhancing the compactness and cost-effectiveness of small information terminals.
Implementation Method 1
a flying capacitor; a first output capacitor connected with the first output terminal; a second output capacitor connected with the second output terminal
Data Source
AI summary
A switching power supply apparatus generates a first output voltage with a reversed polarity of an input voltage and a second input voltage of double the input voltage with the reversed polarity, and then outputs them from the first output terminal and the second output terminal. A driver circuit includes a control unit and a first switch to a sixth switch. The driver circuit repeats three charging periods in a time-division manner. The three charging periods are a first charging period during which a flying capacitor is charged with the input voltage, a second charging period in which a low-potential-side terminal of the flying capacitor is connected to a ground terminal and a first output capacitor is charged with a voltage appearing at the other end of the flying capacitor, and a third charging period in which a high-potential-side of the flying capacitor is connected with the first output terminal and a second output capacitor is charged with a voltage appearing at the other end of the flying capacitor.