Charging Circuit Overvoltage Protection via System Voltage Switching
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Solution Overview
Problem
Portable electronic equipment faces battery degradation due to overcurrent and voltage overshoot during charging, particularly in lithium-ion batteries, as existing charging systems struggle to respond quickly to sudden changes in system load.
Innovation Solution
A charging circuit with a monitoring part that detects overvoltage and outputs a signal to disconnect the battery from the adaptor, and a switch that switches the monitoring node from battery voltage to system voltage, allowing for control of the adaptor voltage based on system voltage to prevent overvoltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the responsiveness of the control loop is increased to quickly respond to sudden system load changes, then the response speed improves, but voltage overshoot and undershoot occur leading to battery degradation
Solution Approach 1:
The patent applies preliminary action by detecting voltage overshoot/undershoot conditions before they reach dangerous levels and preemptively adjusting the charging control. The monitoring circuit continuously tracks battery voltage and current, and when sudden load changes are detected, the control circuit预先 (in advance) modifies charging parameters to prevent voltage excursions that would cause battery damage.
Solution Approach 2:
The patent implements feedback control by continuously monitoring battery voltage and current during charging operations. The monitoring circuit provides real-time feedback to the control circuit, which adjusts charging parameters based on the observed voltage responses to system load changes. This closed-loop feedback mechanism enables the system to respond to sudden load changes while maintaining voltage within safe boundaries, thus preventing both overshoot and undershoot conditions.
2Reliability
If current feedback control is implemented to prevent overcurrent to the battery, then battery life is extended, but the system cannot respond quickly enough to sudden load changes causing voltage overshoot
Solution Approach 1:
The patent applies preliminary action by implementing a monitoring circuit that continuously tracks charging current and voltage at rates faster than traditional feedback loops. When sudden load changes are detected, the system preemptively adjusts current limits before voltage overshoot can occur, thus maintaining both high responsiveness and battery protection.
Solution Approach 2:
The patent implements dynamics by making the charging control parameters adaptive rather than fixed. The control circuit dynamically adjusts current and voltage limits based on real-time system conditions, including sudden load changes. This dynamic adjustment allows the system to respond quickly to changing conditions while maintaining appropriate protection levels, resolving the contradiction between responsiveness and battery life extension.
3Stability of the object's composition
If the AC adaptor side control response is slowed to match battery side responsiveness, then voltage stability improves, but the system cannot handle sudden load changes effectively
Solution Approach 1:
The patent implements dynamics by creating a multi-rate control system where the AC adaptor side and battery side operate at different response speeds. The monitoring circuit runs at a high speed to detect sudden load changes, while the control circuit selectively applies adjustments at appropriate rates. This dynamic, multi-rate approach allows the system to maintain voltage stability during normal operation while effectively handling sudden load changes without compromising either stability or adaptability.
Data Source
AI summary
A charging circuit includes a monitoring part configured to monitor a battery voltage applied to a battery and configured to output an overvoltage signal when the battery is in an overvoltage condition a protection part configured to electrically disconnect the battery from an adaptor when receiving the overvoltage signal, and a switch which, when the battery is electrically disconnected from the adaptor, switches a monitoring node for an adaptor voltage outputted from the adaptor, from a supply node of the battery voltage to a supply node of a system voltage, which is applied to a system electrically connected with the battery and the adaptor, based on the overvoltage signal to cause a control command for controlling the adaptor voltage based on the system voltage to be outputted.