Voltage Regulator Startup Control Using Op-Amp State Detection

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

VSEngineering Contradiction Analysis

1Reliability

If a power source voltage-monitoring circuit is included to ensure safe operation, then the load circuit is protected from high voltages, but the start-up time increases and the semiconductor device size increases

Engineering Contradiction:

Improveprotection of load circuitVSAvoidstart-up time

Core Design Contradiction:

ReliabilityVSLoss of time

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's existing voltage comparison function. The operational amplifier compares the output voltage (through feedback) with a reference voltage, and this same comparison mechanism is used to determine whether the operational amplifier is operating within its valid voltage range, thereby eliminating the need for a separate monitoring circuit while maintaining protection functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The operational amplifier is made multi-functional by using its voltage comparison capability for both voltage regulation (comparing feedback voltage with reference voltage) and safety monitoring (determining if input voltage is within operating range). This single component performs multiple functions that previously required separate circuits, reducing overall device complexity and start-up time.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a power source voltage-monitoring circuit is included to ensure safe operation, then the load circuit is protected from high voltages, but the semiconductor device size increases

Engineering Contradiction:

Improveprotection of load circuitVSAvoidsemiconductor device size

Core Design Contradiction:

ReliabilityVSArea of stationary object

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's existing voltage comparison function. The operational amplifier compares the output voltage (through feedback) with a reference voltage, and this same comparison mechanism is used to determine whether the operational amplifier is operating within its valid voltage range, thereby eliminating the need for a separate monitoring circuit while maintaining protection functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the voltage regulation function and the voltage safety monitoring function into a single integrated circuit block. The operational amplifier and its feedback network handle both the regulation task and the safety monitoring task simultaneously, consolidating multiple functions into one unit and reducing the overall semiconductor device area.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the voltage regulator waits for sufficient power source voltage before operation, then the operational amplifier operates within its valid voltage range, but the start-up time becomes relatively long

Engineering Contradiction:

Improveoperational amplifier operation within valid voltage rangeVSAvoidstart-up time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary protection action by having the detecting circuit continuously monitor the operational amplifier's operating state and immediately control the output transistor to become non-conductive when the operational amplifier is not within its operating voltage range. This preliminary control mechanism prevents harmful output before it can occur, eliminating the need to delay start-up until voltage conditions are perfect.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback from the detecting circuit that monitors the operational amplifier's operating state. The detecting circuit provides real-time information about whether the operational amplifier is operating within its valid voltage range, and this feedback immediately controls the output transistor's conduction state, enabling rapid response without delayed start-up.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12079018B2Voltage regulator

Publication Date: 2024.09.03 KIOXIA CORP

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.