Clamp-Circuit Regulator for Low-Voltage Power Loss Reduction

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Solution Overview

Problem

Conventional regulators with semiconductor integrated circuits experience increased current consumption due to constant load current detection, even when the load is low, which affects their efficiency and responsiveness.

Innovation Solution

A regulator design incorporating a first transistor, a feedback circuit, and a clamp circuit with P-channel or N-channel field effect transistors, where the clamp circuit sets the drain voltage of a second transistor to match the output voltage, reducing current flow when the input voltage is low, thereby minimizing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the output MOSFET and current detection MOSFET share gates and sources to detect load current, then load response performance is improved, but current consumption increases when input voltage is low

Engineering Contradiction:

Improveload response performanceVSAvoidcurrent consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The clamp circuit dynamically adjusts the operating state of the current detection MOSFET based on voltage conditions. When input voltage is lower than output set voltage, the clamp circuit clamps the drain voltage to prevent the MOSFET from being fully conductive, thereby dynamically reducing current consumption while maintaining load detection capability when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the voltage parameter at the drain of the current detection MOSFET through the clamp circuit. By clamping the drain voltage to a specific level, the operating point of the MOSFET is changed, reducing the current flow through the detection path when full conduction is not necessary, thus reducing power consumption.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the current detection MOSFET is made completely conductive to improve detection accuracy, then measurement precision is improved, but power loss increases

Engineering Contradiction:

Improveload current detection accuracyVSAvoidpower loss

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The clamp circuit applies partial conduction to the current detection MOSFET by clamping the drain voltage. This partial action is sufficient to maintain adequate detection precision for the application, while avoiding the excessive conduction that would cause unnecessary power loss, thus achieving an optimal balance between precision and efficiency.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11068004B2Regulator with reduced power consumption using clamp circuit

Publication Date: 2021.07.20 ROHM CO LTD

AI summary

A regulator includes: a first transistor connected between an input terminal and an output terminal; a feedback circuit configured to control a control voltage of a control electrode of the first transistor such that a voltage of the output terminal approaches a target voltage according to a feedback voltage proportional to the voltage of the output terminal; a second transistor having one end connected to the input terminal and a control electrode to which the control voltage is applied in common with the first transistor; and a clamp circuit configured to set the other end of the second transistor to a voltage determined by the voltage of the output terminal.