Overvoltage-Proof Circuit with Delayed Protection Switching
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Solution Overview
Problem
Circuits with components of low withstanding voltage are vulnerable to damage from overvoltage during power switching or abnormal voltage interference, leading to reduced performance and service life, and existing overvoltage protection solutions often compromise circuit performance or cause electrical leakage.
Innovation Solution
An overvoltage-proof circuit design that includes a protected circuit with operational switches and a protecting circuit coupled between input and output terminals, where the protecting circuit operates before enablement signal transitions to prevent overvoltage damage, and can continue protection regardless of the protected circuit's enabled or disabled state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a component of low withstanding voltage is used in the main signal path to achieve lower power consumption and less circuit area, then power consumption and circuit area are reduced, but the component becomes vulnerable to overvoltage damage during switching or abnormal voltage interference
Solution Approach 1:
The protecting circuit is enabled before the protected circuit through a delay circuit that generates a switch signal with a time delay relative to the enablement signal. This preliminary activation ensures that protection is in place before overvoltage conditions can occur during power-on or switching transitions, preventing damage to the low withstanding voltage component while maintaining its operational benefits
2Reliability
If a general overvoltage protection circuit is equipped to protect the low withstanding voltage component, then component protection is improved, but the protection circuit decreases the performance of the protected circuit or causes electric leakage
Solution Approach 1:
The protecting circuit acts as an intermediary element connected in parallel with the protected circuit, controlled by a switch that is enabled before the protected circuit. This intermediary structure isolates the protection mechanism from the main signal path, allowing it to clamp overvoltage conditions without interfering with the normal operation or performance of the protected circuit, thus avoiding electric leakage and performance degradation
Solution Approach 2:
The delay circuit generates a switch signal that activates the protecting circuit before the protected circuit becomes operational. This timing control ensures that protection is established in advance, preventing overvoltage damage during critical transition periods while keeping the protection circuit inactive during normal operation, thereby maintaining optimal circuit performance
Data Source
AI summary
The present invention discloses an overvoltage-proof circuit capable of preventing damage caused by an overvoltage at moments of starting and/or stopping operation. An embodiment of the overvoltage-proof circuit includes a protected circuit and a protecting circuit. The protected circuit receives a power supply voltage to operate, and includes: a protected component, in which an upmost voltage that the protected component can withstand is lower than the power supply voltage; and at least one operational switch(es) operable to enable or disable the protected circuit according to an enabling signal. The protecting circuit is coupled to the protected component, and starts protecting the protected circuit from an overvoltage before a transition of the enabling signal, in which the overvoltage is greater than the upmost voltage.