LDO Transistor Assembly for Fast Load-Transient Voltage Stability
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Solution Overview
Problem
Existing voltage regulators, particularly low dropout (LDO) regulators, face challenges in efficiently managing voltage variations caused by abrupt changes in load current, which can lead to instability and potential damage to components.
Innovation Solution
The proposed voltage regulator design includes a non-inverting stage with a first input transistor and a second biasing transistor coupled in series, where the second transistor is controlled by a third voltage that opposes the variation of the first voltage. This design also incorporates a circuit for generating the control voltage, which receives the first voltage as input and generates a voltage with opposite variation type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional LDO regulator is used, then the output voltage is close to the input voltage, but the regulator cannot respond quickly to abrupt changes in load current
Solution Approach 1:
The patent applies dynamics by making the biasing transistor's conductivity adjustable based on load conditions. The second transistor's gate voltage is dynamically controlled to increase its conductivity when load current changes abruptly, enabling faster response. This dynamic adjustment allows the regulator to adapt its internal resistance characteristics in real-time, improving response speed while maintaining stability.
Solution Approach 2:
The patent implements feedback through a control circuit that monitors the output voltage and adjusts the biasing transistor's gate voltage accordingly. When the output voltage deviates due to load changes, the feedback mechanism modifies the biasing transistor's conductivity to counteract the deviation, enabling quick correction and maintaining output stability simultaneously.
2Reliability
If the regulator uses a simple structure, then the device complexity is low, but it cannot effectively compensate for voltage variations
Solution Approach 1:
The biasing transistor serves multiple functions: it provides standard biasing for the error amplifier and simultaneously acts as a dynamic compensation element whose conductivity can be adjusted to counteract load variations. This multi-functionality enables effective voltage variation compensation without adding separate dedicated compensation circuits, thus limiting the increase in device complexity.
Solution Approach 2:
The patent changes the conductivity parameter of the biasing transistor dynamically based on operating conditions. By controlling the gate voltage of the second transistor, its conductivity is adjusted to provide appropriate compensation for different load scenarios. This parameter change approach enables adaptive compensation without requiring complex circuit topologies.
Data Source
AI summary
Provided is a voltage regulator supplying a first voltage on a first output node and comprising a first input transistor of a non-inverting stage and a second biasing transistor of the non-inverting stage. The first and second transistors are coupled in series, in this order, between the first node and a second node of application of a second reference voltage. The second transistor is being configured to be controlled by a third voltage depending on the first voltage.