Adaptive Drive-Strength Charge Pump for Stable Low-Ripple Output
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Solution Overview
Problem
State-of-the-art regulated charge pumps require significant capacitance at the output terminal to reduce ripple, leading to increased integrated circuit area and operational delays, which complicates the generation of a stable output voltage.
Innovation Solution
A regulated charge pump with adaptive drive strength, utilizing a comparator, clock generator, and dual open-loop feedback paths to dynamically adjust the number of active pumping stages and clock frequency based on load conditions, allowing for variable driving strength and reduced ripple without the need for large capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large integrated circuit capacitors are used to decrease ripple and generate stable output voltage, then output voltage stability is improved, but integrated circuit area increases significantly
Solution Approach 1:
The charge pump implements dynamic operation by varying the clock frequency based on load conditions. The control circuit monitors the output voltage and adjusts the clock frequency to match the actual load demand, allowing the system to maintain stability with smaller capacitors by responding adaptively to changes rather than relying on large fixed capacitance for ripple suppression
Solution Approach 2:
The system changes the operating parameters (clock frequency, pumping stage activation) based on load conditions. By dynamically adjusting these parameters, the charge pump can maintain stable output voltage without requiring large capacitors, as the system adapts its charging rate to match the load current requirements in real-time
2Power
If more pumping stages are activated to increase driving strength, then output current capability is improved, but power consumption increases
Solution Approach 1:
The charge pump dynamically adjusts the number of active pumping stages based on the detected load current. When high current is needed, more stages are activated; when load is light, fewer stages operate. This dynamic adaptation ensures high current capability is available when needed while minimizing power consumption during normal operation
Solution Approach 2:
The system changes the operational state of different pumping stages based on load requirements. The control circuit activates or deactivates specific stages to match the demanded current level, allowing the system to provide high driving strength on demand while maintaining low power consumption during typical operation
3Speed
If clock frequency is increased to improve response speed, then charging rate is improved, but power consumption increases
Solution Approach 1:
The charge pump implements dynamic clock frequency adjustment based on load conditions and output voltage requirements. The control circuit increases clock frequency only when rapid charging is needed to correct voltage drops under heavy load, and reduces frequency during steady-state operation, thereby achieving fast response when necessary while minimizing power consumption during normal operation
Data Source
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Figure 2B
AI summary
A regulated charge pump includes a comparator having a first input and a second input for receiving a reference voltage, a clock generator having an input coupled to an output of the comparator, a first open-loop charge pump in a first feedback path having an input coupled to a first output of the clock generator, and an output coupled to the first input of the comparator, and a second open-loop charge pump in a second feedback path having an input coupled to a second output of the clock generator, and an output coupled to the first input of the comparator. The output of the first open-loop charge pump and the output of the second open-loop charge pump comprise an output of the regulated charge pump