Switched Capacitor Controller With Variable On-Resistance Transistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switched capacitor controllers in the semiconductor industry face issues with high in-rush current during initial charging and potential damage from short-circuit conditions, as they often exceed the maximum current capacity of the voltage source and can be damaged by large short-circuit currents.
Innovation Solution
The implementation of a switched capacitor controller with transistors having multiple on-resistance values, where a higher on-resistance is used during the start-up phase to limit the charging current and a lower on-resistance is used after the start-up phase to maintain the voltage, along with a control circuit that generates clock and control signals to manage the transistors' operation and prevent short-circuit damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a switched capacitor controller uses a transistor with low on-resistance to charge the pump capacitor, then the charging speed is improved, but the in-rush current exceeds the maximum current capacity of the voltage source
Solution Approach 1:
The transistor's on-resistance is dynamically changed during operation. During start-up, the transistor operates in a first state with higher on-resistance to limit in-rush current. After the pump capacitor is charged, the transistor transitions to a second state with lower on-resistance to enable faster charging. This dynamic state change resolves the contradiction between charging speed and in-rush current limitation.
2Power
If the controller allows high current flow during normal operation, then the power delivery capability is improved, but the controller is damaged by large short-circuit currents
Solution Approach 1:
The transistor dynamically adjusts its on-resistance based on operating conditions. During normal operation, it maintains lower on-resistance for high power delivery. During short-circuit conditions, it transitions to higher on-resistance state to limit current flow and protect the controller, thus resolving the contradiction between power delivery capability and reliability.
Data Source
AI summary
In one embodiment, a charge pump controller is configured with transistors having at least two different selectable on-resistance values may be used to charge a pump capacitor.