Charge Pump Regulator Feedback Control for Low Ripple Output
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Solution Overview
Problem
Existing charge pump regulators face issues with large input ripple, high frequency noise, and increased power consumption due to large open loop resistance, which affects efficiency and requires large filters to manage low frequency noise.
Innovation Solution
A charge pump regulator with a current control element on the charge or discharge path, driven by an output-dependent feedback signal, reduces input ripple without additional series resistance, using voltage-controlled power sources and multi-phase non-overlapping clocks to control current flow and minimize noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a variable resistor is inserted between the charge pump and ground terminal to limit charge current and reduce input current ripple, then the input current ripple is reduced, but the current ripple in the discharge phase remains large and high frequency noise occurs during the blank period
Solution Approach 1:
The charge pump circuit is divided into multiple independent phases (first charge phase, second charge phase, first discharge phase, second discharge phase) with dedicated current control elements for each phase. This segmentation allows independent control of current in each phase, enabling reduction of input current ripple during charge phases while maintaining proper discharge current control during discharge phases, and eliminating high frequency noise during blank periods through coordinated phase switching.
Solution Approach 2:
The patent employs dynamic current control by using voltage-controlled current sources that adjust their output current based on real-time feedback signals. The current control elements dynamically modify their resistance characteristics during different phases of operation, allowing optimal current limiting during charge phases while maintaining low output impedance during discharge phases, thereby reducing both input current ripple and high frequency noise.
2Object-affected harmful factors
If a variable resistor is inserted between the power supply and input terminal of the charge pump to control input current and reduce supply voltage disturbance, then the supply voltage disturbance is reduced, but the input series resistance is increased and power consumption is increased
Solution Approach 1:
The patent uses dynamic impedance control through voltage-controlled current sources that present high impedance during charge phases to limit input current and reduce supply voltage disturbance, then switch to low impedance during discharge phases to minimize power loss. This dynamic switching of impedance characteristics allows the circuit to achieve both supply voltage stabilization and low power consumption, resolving the contradiction between reducing supply voltage disturbance and minimizing power loss.
Solution Approach 2:
The charge pump operates in periodic cycles with distinct charge phases and discharge phases. During charge phases, current control elements are activated to limit input current and reduce supply voltage disturbance. During discharge phases, the control elements are deactivated or switched to a low-impedance state to minimize power loss. This periodic switching between high-impedance current limiting mode and low-impedance power-efficient mode resolves the contradiction between reducing supply voltage disturbance and minimizing power consumption.
3Object-affected harmful factors
If a current source is inserted between the power supply and input terminal of the charge pump to provide stable input current and reduce input ripple, then the input ripple is reduced, but an added element is required outside the charge pump
Solution Approach 1:
The patent integrates current control functionality directly into the charge pump circuit by incorporating current control elements as integral parts of the charge and discharge paths. Rather than adding separate external current sources, the control elements are merged with the existing switch-capacitor network, sharing common nodes and control signals. This integration reduces input ripple while avoiding the need for additional external components, thereby reducing device complexity.
Solution Approach 2:
The voltage-controlled current sources serve multiple functions: they act as current limiters during charge phases to reduce input ripple, as switches for phase transitions, and as part of the feedback control system. By making the current control elements multi-functional, the patent eliminates the need for separate dedicated current source components, thereby reducing overall device complexity while achieving effective input ripple reduction.
4Measurement precision
If switches are switched with a modulated switching frequency to connect capacitor to power supply or output terminal, then a regulated voltage is produced, but large input ripple and large supply voltage disturbance are caused
Solution Approach 1:
The patent employs feedback control by using a feedback signal that responds to the output voltage to control the switching frequency and duty cycle of the charge pump. This feedback mechanism allows the circuit to maintain precise regulated voltage output while dynamically adjusting the switching parameters to minimize input ripple and supply voltage disturbance. The feedback loop continuously monitors output conditions and adjusts current control element parameters accordingly, achieving both precise voltage regulation and low input ripple.
Solution Approach 2:
The patent uses dynamic switching frequency and duty cycle adjustment based on real-time feedback. The current control elements dynamically modify their characteristics during different phases of operation, allowing the circuit to maintain precise voltage regulation while adapting switching parameters to minimize input ripple. This dynamic control approach enables the charge pump to achieve both regulated voltage output and low input ripple across varying load conditions.
Data Source
AI summary
A charge pump regulator has a charge pump to establish a charge path and a discharge path alternately, so as to produce a regulated voltage on an output terminal. The charge pump has at least a current control element on the charge path or the discharge path to control the current flowing therethrough according to an output-dependent feedback signal.