Linear Voltage Regulator Sub-Reference Output via Current Injection

Solution Overview

Problem

Conventional linear voltage regulators face challenges in generating sub-reference output voltages, as they require larger implementation areas, introduce noise, and experience start-up issues due to the need for resistive dividers to scale down reference voltages.

Innovation Solution

A linear voltage regulator design incorporating a voltage reference, a pass transistor, a voltage divider network, and two amplifiers, where the second amplifier injects a current proportional to the difference between the output and a node voltage in the divider network, allowing for sub-reference output voltages without the need for resistive dividers, thus reducing noise and implementation area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional linear voltage regulators use resistive dividers to scale down reference voltages for sub-reference output, then sub-reference output voltage is achieved, but implementation area increases and noise is introduced

Engineering Contradiction:

Improvesub-reference output voltage generationVSAvoidimplementation area

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The patent extracts and eliminates the resistive divider component from the voltage regulator architecture. By using a current mirror circuit instead, the design removes the source of noise and area consumption associated with resistive dividers while maintaining the ability to generate sub-reference output voltages.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the resistive divider (passive mechanical/electrical component) with an active current mirror circuit using transistors. This replacement achieves the same voltage scaling function without the drawbacks of resistive dividers, particularly noise generation and large implementation area.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If conventional linear voltage regulators use resistive dividers to scale down reference voltages, then sub-reference output voltage is achieved, but noise is introduced in the regulated output voltage

Engineering Contradiction:

Improvesub-reference output voltage generationVSAvoidnoise

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the resistive divider component from the voltage regulator architecture. By using a current mirror circuit instead, the design removes the source of noise and area consumption associated with resistive dividers while maintaining the ability to generate sub-reference output voltages.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If conventional linear voltage regulators use resistive dividers for voltage scaling, then sub-reference output is achieved, but start-up issues occur

Engineering Contradiction:

Improvesub-reference output voltage generationVSAvoidstart-up performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent substitutes the resistive divider (passive mechanical/electrical component) with an active current mirror circuit using transistors. This replacement achieves the same voltage scaling function without the drawbacks of resistive dividers, particularly noise generation and large implementation area.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8536934B1Linear voltage regulator generating sub-reference output voltages

Publication Date: 2013.09.17 TEXAS INSTRUMENTS INC

AI summary

A linear voltage regulator includes a pair of amplifiers. A first amplifier of the pair is used in conventional fashion to generate a regulated output voltage by controlling an impedance of a pass transistor in the linear voltage regulator, the controlling being based on a difference between a reference voltage and a voltage at a first node in a voltage divider network connected between the output terminal of the voltage regulator and a ground terminal. The second amplifier of the pair compares the regulated output voltage and a voltage at a second node in the voltage divider network, and injects a proportional current into the first node. Generation of a regulated output voltage lesser than the reference voltage is thereby enabled.