Charge Pump Switching Control for Capacitor Voltage Drift
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Solution Overview
Problem
Charge pumps coupled with current sources face challenges in maintaining stability due to charge accretion and voltage drift, leading to potential switch overheating and failure, especially when using current sources that behave like regulators with relevant time scales affecting switch configurations.
Innovation Solution
A charge management subsystem with a switching network and controller that controls residence times and configurations to ensure each pump capacitor returns to an initial state at the start of each cycle, using feedback and proportional-integral-derivative control to manage charge and stabilize the capacitor network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a charge pump is coupled with a current source, then power conversion functionality is achieved, but charge accumulation and voltage drift occur causing instability
Solution Approach 1:
The patent implements a feedback mechanism that monitors the charge state of pump capacitors and adjusts switching configurations accordingly. The controller detects charge accumulation trends and modifies the switching sequence or duration to counteract drift, ensuring the capacitors return to their initial state periodically. This closed-loop control stabilizes the charge pump operation when coupled with current sources.
Solution Approach 2:
The patent employs periodic resetting of pump capacitor charge states by strategically configuring switching networks at specific intervals. The switching controller is designed to return each pump capacitor to its initial state at predetermined points in the switching sequence, creating a periodic charge management pattern that prevents cumulative drift and maintains long-term stability.
2Power
If pump capacitors are used to transfer energy, then power conversion is achieved, but voltage drift causes switch voltage to exceed ratings leading to overheating
Solution Approach 1:
The patent applies preliminary action by proactively managing capacitor charge states before voltage drift can cause harmful effects. The switching controller is designed to detect and correct charge accumulation trends early in the operation cycle, resetting capacitor voltages to safe levels before they can cause switch overvoltage conditions. This preventive approach protects switches from exceeding their voltage ratings.
Solution Approach 2:
The patent introduces an intermediary control mechanism (the switching controller with feedback) that mediates between the pump capacitors and the switches. This intermediary monitors capacitor voltage drift and adjusts switching configurations to prevent excessive voltage from reaching the switches, thereby protecting them from overheating and failure while maintaining power conversion functionality.
3Productivity
If residence times are extended to improve power transfer, then energy conversion efficiency increases, but charge accumulation accelerates causing faster voltage drift
Solution Approach 1:
The patent implements dynamic adjustment of residence times based on real-time charge state monitoring. Rather than using fixed residence times, the switching controller dynamically modifies the duration of switching states to optimize the balance between power transfer efficiency and charge management. When charge accumulation is detected, residence times are adjusted to facilitate faster resetting, maintaining stability while preserving overall conversion efficiency.
Data Source
AI summary
An apparatus for power conversion includes a switching network that controls interconnections between pump capacitors in a capacitor network that has a terminal coupled to a current source, and a charge-management subsystem. In operation, the switching network causes the capacitor network to execute charge-pump operating cycles during each of which the capacitor network adopts different configurations in response to different configurations of the switching network. At the start of a first charge-pump operating cycle, each pump capacitor assumes a corresponding initial state. The charge-management subsystem restores each pump capacitor to the initial state by the start of a second charge-pump operating cycle that follows the first charge-pump operating cycle.