Solid State Switch Monitoring for Fault-Tolerant Power Keys
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Solution Overview
Problem
Mechanical user input keys in electronic devices are prone to reliability issues due to wear and tear, especially power keys which are frequently used, and errors in sensing ICs can leave devices inoperable when in a low power or unpowered state.
Innovation Solution
A solid state switch monitoring system that includes a sensing component coupled to a solid state switch, which periodically generates a clocked pulse to determine the actuated state of the switch, and a supervisory controller to restart the sensing component if it becomes inoperative, ensuring reliable operation even when other components are powered down or in a low power state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical actuation keys are used for user input control, then the implementation is simple, but the reliability deteriorates due to wear and tear from repeated use
Solution Approach 1:
The patent replaces mechanical actuation keys with solid state keys that detect changes in electrical characteristics (resistance, capacitance, or inductance) based on user actuation. This substitution eliminates moving parts and mechanical wear, thereby improving reliability while maintaining the key function. The sensing integrated circuits detect these electrical characteristic changes to generate corresponding input states without mechanical contact.
2Reliability
If solid state keys are used to eliminate moving parts, then the reliability improves, but the risk of sensing IC errors increases which can leave the device inoperable
Solution Approach 1:
The patent implements a feedback mechanism where a supervisory controller continuously monitors the output of the sensing integrated circuit. When an error is detected in the sensing IC output, the supervisory controller activates a backup power key circuit to ensure the device can still be powered on. This feedback loop detects and responds to sensing IC failures, preventing the device from being left inoperable.
Solution Approach 2:
The patent prepares a backup power key circuit in advance that can be activated if the primary sensing IC fails. This beforehand cushioning ensures that even if the sensing IC makes an error, the device has a pre-prepared fallback mechanism to maintain operability, thus cushioning against the harmful effect of sensing IC errors.
3Speed
If the sensing IC is always active to monitor solid state switch status, then the response time improves, but the power consumption increases when other components are powered down
Solution Approach 1:
The patent implements periodic polling of the solid state switch by the supervisory controller instead of continuous monitoring. The supervisory controller periodically checks the switch state even when the main sensing IC is in low-power mode, balancing responsive detection with reduced power consumption during inactive periods.
Solution Approach 2:
The patent enables the sensing IC to remain in a low-power state during normal operation and only activates full monitoring when needed, such as during power-up sequences or when triggered by specific events. This preliminary preparation allows the system to maintain readiness while minimizing continuous power consumption.
Data Source
AI summary
A solid state switch (SSS) monitoring system of an electronic device includes a SSS sensing component that is electrically coupled to a solid state switch. The SSS sensing component generates a switch state signal to indicate a corresponding one of an actuated and an unactuated state of the solid state switch. A controller is communicatively coupled to the SSS sensing component. The controller restarts the SSS sensing component in response to determining that the SSS sensing component is in an inoperative state.