Voltage Regulator Output Cutoff for Fast Safe Start-Up
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Solution Overview
Problem
Conventional voltage regulators have a long start-up time and increased semiconductor device size due to the need for a power source voltage-monitoring circuit, which delays their operation until the power source voltage is sufficient, and they struggle to control output voltage when the input voltage is lower than the operating range.
Innovation Solution
A voltage regulator design that includes a detecting circuit to monitor the operational amplifier's state, preventing the output transistor from conducting when the operational amplifier is not within its operating voltage range, thus preventing unintended high voltages from reaching the load circuit, and allowing quick start-up without monitoring the power source voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power source voltage-monitoring circuit is included to ensure safe operation, then reliability is improved, but device complexity and size increase
Solution Approach 1:
The patent extracts the voltage monitoring function from a separate power source voltage-monitoring circuit and integrates it into the operational amplifier itself. The operational amplifier is designed to automatically stop operating when the power source voltage is insufficient, eliminating the need for external voltage monitoring circuits while maintaining safe operation.
Solution Approach 2:
The operational amplifier is designed to perform dual functions: voltage regulation and voltage monitoring. By making the operational amplifier itself sensitive to power source voltage levels, it can both regulate output voltage and detect insufficient input voltage conditions, reducing the need for separate monitoring circuitry.
2Reliability
If a power source voltage-monitoring circuit is included to prevent operation at insufficient voltage, then reliability is improved, but start-up time increases
Solution Approach 1:
The operational amplifier is designed with built-in voltage threshold detection capability that is always active, eliminating the need to wait for external monitoring circuits to detect voltage levels. The amplifier automatically responds to insufficient voltage conditions as they occur, enabling faster start-up while maintaining safety.
3Productivity
If the operational amplifier operates without voltage monitoring, then start-up time is reduced, but the load circuit may be exposed to harmful high voltages
Solution Approach 1:
The operational amplifier is designed to self-monitor the power source voltage and automatically stop operating when voltage conditions are insufficient. This self-service monitoring capability eliminates the need for external monitoring circuits while preventing harmful output voltages, achieving both fast start-up and safe operation.
Data Source
AI summary
A voltage regulator includes an operational amplifier that compares a feedback voltage that is proportional to an output voltage and a predetermined reference voltage that corresponds to a desired output voltage. The operational amplifier controls the conduction state of an output transistor according to the comparison. A detecting circuit monitors the operating state of the operational amplifier, and in the case that the operational amplifier is not operating, outputs a signal which causes the output transistor to be placed in a non-conductive state.