Three-Phase Charge Pump Reduces Current Ripple
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Solution Overview
Problem
Conventional charge pumps experience significant current and voltage ripples, leading to high noise due to their operation in only two phases, which existing solutions have been unable to adequately address.
Innovation Solution
A charge pump operating in at least three phases with balanced operational durations and currents, reducing current and voltage ripples and noise by distributing charging and discharging phases more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional charge pump operates in two phases (charging and discharging), then the circuit structure is simple, but the current ripple and voltage ripple are huge, causing high noise
Solution Approach 1:
The patent segments the charging and discharging operations into multiple independent phases by dividing the capacitor array into multiple groups. Each group operates in a separate phase, distributing the total charging and discharging current across multiple time intervals. This segmentation of the operational phases reduces the peak current in each phase and smooths the overall current waveform, thereby reducing current ripple and associated noise while maintaining circuit simplicity.
2Ease of operation
If the charge pump operates in two phases with equal duration, then the control is simple, but the discharging current is two times the output current, creating huge current ripple
Solution Approach 1:
The patent implements periodic action by cycling through multiple phases in a repeating sequence. The charge pump operates through Phase 1 (charging Group 1), Phase 2 (charging Group 2), Phase 3 (discharging Group 1), and Phase 4 (discharging Group 2), then repeats. This periodic multi-phase operation distributes the current demand over time, ensuring that at any given moment only one phase is active, thereby reducing peak current and current ripple while maintaining simple periodic control.
3Object-generated harmful factors
If more phases are introduced to reduce current ripple, then the noise is reduced, but the device complexity increases
Solution Approach 1:
The patent merges multiple capacitor groups into a unified array that shares common switching control logic. Groups 1 and 2 (each containing multiple capacitors) are managed by a coordinated switching network that controls all phases through a systematic pattern. This merging approach allows the system to achieve multi-phase operation with reduced noise while avoiding the complexity of completely independent phase controllers, as the switching patterns are systematically related and can be managed through unified control.
Data Source
AI summary
A low noise multiphase charge pump comprises a plurality of capacitors and a plurality of switches configured as a network, the switches are so switched that the charge pump operates in at least three phases by turns, and the operational durations and the operational currents of the phases are preferably balanced, so as to reduce the noise of the charge pump.