Linear Voltage Regulator Transient Response Control

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Solution Overview

Problem

Conventional linear voltage regulators experience significant overshoot and oscillation in output voltage during transient changes in the input voltage source, failing to meet application specifications.

Innovation Solution

Incorporation of an event detecting circuit, enable controlling circuit, and voltage clamping circuit to detect transient events and clamp the potential difference between the regulating transistor's electrodes, preventing dramatic changes in the transistor's operation and stabilizing the output voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the regulating transistor is used to control output voltage through feedback control, then the output voltage is maintained at the desired regulation value, but the output voltage experiences huge overshoot and extensive oscillation during input voltage transients

Engineering Contradiction:

Improveoutput voltage regulationVSAvoidoutput voltage stability during transient

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The event detecting circuit detects transient events of the input voltage source in advance and generates an event signal. The enable controlling circuit uses this event signal to activate the voltage clamping circuit before the transient fully impacts the regulating transistor, preventing dramatic changes in transistor operation and reducing output voltage overshoot and oscillation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The voltage clamping circuit acts as an intermediary between the input voltage source and the regulating transistor. It clamps the potential difference between the source and gate electrodes during transient events, mediating the impact of input voltage changes and preventing direct transmission of transient effects to the transistor operation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the feedback control loop is used to settle output voltage after transient, then the output voltage eventually returns to regulation value, but the settling time is extended due to extensive oscillation

Engineering Contradiction:

Improveoutput voltage recoveryVSAvoidsettling time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The voltage clamping circuit applies preliminary anti-action by clamping the potential difference between the source and gate electrodes during transient events. This counteracts the harmful effects of input voltage transients before they can cause large deviations in output voltage, reducing the time required for the feedback control loop to settle the output voltage

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS7450354B2Linear voltage regulator with improved responses to source transients

Publication Date: 2008.11.11 GLOBAL MIXED MODE TECH

AI summary

A linear voltage regulator has a regulating transistor with a first channel electrode receiving an input voltage source and a second electrode providing an output voltage. A control electrode of the regulating transistor is controlled by an error amplifying circuit based on comparison between a feedback signal of the output voltage and a reference voltage. An event detecting circuit is coupled to the input voltage source for detecting occurrence of a transient in the input voltage source. In response to the detected transient event, an enable controlling circuit generates an enable signal for determining an effective operation time of a voltage clamping circuit. During such effective operation time, a potential difference between the first channel electrode and the control electrode is limited within a predetermined clamp voltage for preventing the regulating transistor from being dramatically changed in operation.