Charge Pump Circuit Bipolar Output Ripple Reduction
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Solution Overview
Problem
Existing charge pump circuits suffer from limited charge conversion efficiency and significant ripple in output voltage, particularly the four-phase switched charge pump circuits, which hinder their application in ICs requiring high voltage and efficient DC voltage conversion.
Innovation Solution
A new charge pump circuit architecture utilizing four sets of switch devices that can operate with either four-phase or two-phase clock signals, comprising nine switches and four capacitors, to produce bipolar voltage outputs higher than the input voltage, with flexible operation and reduced ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If four-phase switched charge pump circuit is used, then bipolar voltage output is achieved, but output voltage ripple increases
Solution Approach 1:
The charge pump circuit is divided into two independent but synchronized two-phase charge pump sub-circuits operating in parallel. Each sub-circuit handles one polarity of the bipolar output, allowing the harmful ripple effects to be distributed and filtered more effectively while maintaining the bipolar voltage output capability through coordinated operation of both sub-circuits
2Productivity
If conventional charge pump circuit structure is used, then voltage conversion function is achieved, but charge conversion efficiency is limited
Solution Approach 1:
Two two-phase charge pump sub-circuits are merged into a single integrated circuit structure that produces bipolar voltage output. The merging of these sub-circuits allows for shared components and coordinated operation that improves overall charge conversion efficiency while reducing redundant energy losses associated with separate circuits
Solution Approach 2:
The circuit employs overlapping switching phases and continuous charge transfer mechanisms where the charging action of one sub-circuit overlaps with the discharging action of the other. This continuous operation eliminates idle periods and maintains steady current flow through the load, thereby improving charge conversion efficiency and reducing energy losses
3Reliability
If four-phase clock signaling is used, then complete charge pump operation is achieved, but circuit complexity increases
Solution Approach 1:
The circuit is designed with a universal control architecture where a single two-phase clock signal serves multiple functions: it simultaneously controls both charge pump sub-circuits and generates the necessary timing for all switching operations. This multi-functionality reduces the number of independent control signals needed while maintaining complete and reliable charge pump operation
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 proposed circuit achieves high conversion efficiency and smaller ripple, especially in two-phase operation, enabling wider application and economic benefits through flexible use and improved performance.
Implementation Method 1
a first input terminal of the first transfer capacitor to a first input terminal of the first storage capacitor, and a second input terminal of the first transfer capacitor to a second input terminal of the first storage capacitor
Implementation Method 2
comprising a first transfer capacitor, a first storage capacitor, a second transfer capacitor and a second storage capacitor
Data Source
AI summary
A charge pump circuit with bipolar output comprises a first set of switch device capable of selectively connecting two terminals of a first transfer capacitor to a voltage source and a ground terminal, respectively, a second set of switch device capable of selectively connecting the two terminals of the first transfer capacitor to a grounded first storage capacitor and the voltage source, respectively, a third set of switch device capable of selectively connecting two terminals of a second transfer capacitor to the first transfer capacitor connected to the voltage source and the ground terminal, respectively, and a fourth set of switch device capable of selectively connecting the two terminals of the second transfer capacitor to a grounded second storage capacitor and the ground terminal, respectively. These four sets of switch devices totally have nine switches, and are collocated with clock signals to be selectively driven by a four-phase signal or a two-phase signal so as to produce bipolar voltages with magnitudes higher than the input voltage and also accomplish the highest conversion efficiency.