Multiphase Charge Pump Circuit for Lower Capacitor Conduction Loss
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Solution Overview
Problem
Existing DC voltage converters, such as those based on the Dickson charge pump design, suffer from power losses due to capacitor conduction losses, particularly in battery-powered devices where efficiency is crucial, as they charge capacitors in a single continuous phase, leading to higher voltage differences and increased losses.
Innovation Solution
The proposed DC voltage converter employs a charge pump circuit with multiple stages, each comprising two capacitors, and a switch network that allows for sequential charging in four phases, reducing the initial voltage difference between capacitors by charging them in two successive phases with different capacitors, thereby minimizing capacitor conduction losses through multiphase charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If capacitors are charged in a single continuous phase, then the charging process is simple, but capacitor conduction losses increase due to higher voltage differences
Solution Approach 1:
The charging process is divided into multiple discrete phases (first phase, second phase, third phase, fourth phase) with each phase performing a specific charging function. Different capacitors are charged in different phases, breaking the single continuous charging process into segmented steps that reduce voltage differences during charging.
Solution Approach 2:
The charge pump circuit operates through periodic cycling through four distinct phases. Each phase has specific switch configurations that periodically charge different capacitors from different voltage sources, creating a rhythmic pattern of charging operations that minimizes energy losses.
2Productivity
If multiple capacitors are charged simultaneously, then charging speed increases, but voltage differences between capacitors increase leading to higher losses
Solution Approach 1:
Instead of charging all capacitors simultaneously, the invention segments the charging process so that different capacitors are charged in different phases. This sequential segmentation maintains charging productivity while reducing the voltage differences that cause conduction losses.
Solution Approach 2:
Certain capacitors are charged in advance during specific phases before they are needed for subsequent charging operations. For example, capacitors are preliminarily charged from the input voltage source in earlier phases, preparing them for use in later phases while minimizing energy losses.
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 reduces power losses by limiting the voltage difference during charging, resulting in lower capacitor conduction losses and improved efficiency, especially in battery-powered devices, while maintaining a desired output voltage and load current demand.
Implementation Method 1
each charge pump stage comprising connections for respective first and second capacitors for that stage
Implementation Method 2
the relevant capacitor of the one stage can be charged by the relevant capacitor of the preceding stage
Data Source
AI summary
This application relates to methods and apparatus for DC voltage conversion. A DC converter (100) is described, with a charge pump circuit comprising a plurality of charge pump stages (1401, 1402-1, 1402-2) each charge pump stage comprising connections for respective first and second capacitors for that stage (C1A, C1B; C2A, C2B; C3A, C3B). The charge pump also has a switch network, wherein the switch network comprises, between each successive stage, four switching paths (S7AA, S7AB, S7Ba, S7BB; S6AA, S6AB, S6Ba, S6BB) for separately connecting a respective first electrode of each of the first and second capacitors of one stage to a first electrode either of the first and second capacitors of the preceding stage, so that the relevant capacitor of the one stage can be charged by the relevant capacitor of the preceding stage.