LDO Output Voltage Switching Circuit for Fast Pull-Up
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Solution Overview
Problem
Conventional low-dropout regulators (LDOs) are unable to quickly pull up output voltages, resulting in insufficient power supply to loads.
Innovation Solution
A low-dropout regulator with an output voltage switching circuit, comprising a transistor, a low-dropout linear regulator circuit, a switch error amplifier circuit, a switch component, and a voltage selector circuit, which allows for quick switching between linear regulation and voltage pulling up to meet load requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional low-dropout regulator uses linear regulation circuit only, then output voltage stability is maintained, but output voltage cannot be pulled up quickly
Solution Approach 1:
The regulator is segmented into two distinct circuits: a linear regulation circuit for stable voltage output and a switch error amplifier circuit for rapid voltage pull-up. Each circuit handles specific operational requirements, allowing the system to achieve both stability and speed without excessive complexity.
Solution Approach 2:
The patent implements dynamic switching between two operational modes by selecting different error amplifier circuits based on real-time voltage requirements. The voltage selector circuit dynamically chooses between the linear regulation path and the switch error amplifier path, enabling the system to adapt its behavior to match load demands.
2Power
If conventional low-dropout regulator uses single error amplifier circuit, then circuit simplicity is maintained, but power supply capability to load is insufficient
Solution Approach 1:
The patent creates a universal error amplifier system that can perform multiple functions: the linear regulation error amplifier handles normal stable operation, while the switch error amplifier handles rapid voltage restoration. The voltage selector circuit enables either amplifier to take control based on system needs, providing multi-functionality without requiring completely separate systems.
Solution Approach 2:
The voltage selector circuit acts as an intermediary that mediates between the two error amplifier circuits and the rest of the regulator system. It selects which error amplifier output should control the pass transistor, enabling the system to switch between different power supply modes without direct complex interaction between the amplifiers themselves.
3Speed
If conventional low-dropout regulator uses only linear regulation mode, then voltage precision is maintained, but response time to voltage changes is slow
Solution Approach 1:
The system employs periodic or conditional switching between two error amplifier modes based on voltage difference thresholds. The switch error amplifier activates periodically or conditionally when rapid voltage pull-up is needed, while the linear regulator handles continuous precision maintenance, creating a coordinated periodic action pattern that balances speed and precision.
Data Source
AI summary
A low-dropout regulator having an output voltage switching circuit is provided. In the low-dropout regulator, a low-dropout linear regulator circuit outputs a regulating signal according to a voltage difference between a second terminal of a transistor and a regulating threshold voltage signal or a reference voltage. In the low-dropout regulator, a switch error amplifier circuit outputs a pull-up control signal according to a voltage difference between the second terminal of the transistor and a voltage pull-up switching signal. When a voltage selector circuit of the low-dropout regulator selects the regulating signal, the transistor operates to regulate an output voltage of the low-dropout regulator according to the regulating signal. When the voltage selector circuit selects the pull-up control signal, a switch component is turned on by the pull-up control signal such that the output voltage of the low-dropout regulator is directly pulled up by an input voltage.