Adaptive Well-Switched LDO Circuit for Dual-Voltage Power Paths

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Solution Overview

Problem

Voltage regulators in devices often face inefficiencies and thermal issues due to struggles in supporting different loads with varying power supply voltages, leading to increased power loss and reduced battery life.

Innovation Solution

A dual-input, single-output LDO regulator circuit with adaptive switching, utilizing adaptive transistor well switching and transistor switching based on input and output voltages to optimize power supply paths, enhancing efficiency and thermal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single-input LDO regulator is used, then the circuit is simple, but it cannot support multiple power supply voltages and causes power loss

Engineering Contradiction:

Improvesupport for multiple power supply voltagesVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The LDO regulator is designed with dual input terminals (first input and second input) that can accept different power supply voltages (e.g., battery voltage and USB voltage), enabling a single device to serve multiple power sources and applications without requiring separate regulators for each voltage source

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements dynamic switching between different pass transistors (first pass transistor and second pass transistor) based on which power source is active, allowing the circuit to adapt its configuration in real-time to match the available power supply and optimize performance

Inventive Principle:

Principle #15Dynamics

2Area of moving object

If passive diodes are used for blocking current, then the structure is simple, but they occupy excessive area and cause voltage drops

Engineering Contradiction:

Improvecircuit areaVSAvoidpower loss

Core Design Contradiction:

Area of moving objectVSLoss of energy

Solution Approach 1:

The patent changes the operational parameters of the pass transistors by dynamically adjusting their well connections (source well and drain well) to achieve blocking functionality, replacing the need for passive diodes and reducing both area and voltage drop while maintaining current blocking capability

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the LDO regulator supports varying power supply voltages, then adaptability improves, but thermal issues and power loss increase

Engineering Contradiction:

Improvesupport for varying loads and voltagesVSAvoidheat dissipation

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The regulator dynamically switches between different pass transistors and their associated wells based on the active power source, optimizing the conduction path for each voltage source (e.g., battery vs. USB) to minimize voltage drop and reduce power dissipation as heat, thereby managing thermal issues while maintaining adaptability

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20250343482A1Low-dropout regulator circuit with adaptive transistor well switching

Publication Date: 2025.11.06 QUALCOMM INC

AI summary

Techniques and apparatus for supplying power in a low-dropout (LDO) regulator circuit are provided. One example LDO regulator circuit generally includes a first input, a second input, an output, a first pass transistor, and a second pass transistor. The first pass transistor has a switchable well, a source coupled to the first input of the LDO regulator circuit, and a drain coupled to the output of the LDO regulator circuit. The second pass transistor has a switchable well, a source coupled to the second input of the LDO regulator circuit, and a drain coupled to the output of the LDO regulator circuit.