Dual Feedback Loop LDO Regulator Transient Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power management integrated circuits (PMICs) with single feedback loops face limitations in transient response, leading to larger output capacitors, increased bill of material costs, and reduced efficiency, especially when driving digital loads.
Innovation Solution
A dual feedback loop regulator design that includes a first amplifier, a second amplifier, a transconductance stage with a transistor and current source, and a transimpedance stage, allowing for faster response to voltage fluctuations through a second feedback path, reducing the need for large output capacitors and improving overall system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single feedback loop is used in conventional PMICs, then the circuit complexity is reduced, but the transient response speed deteriorates
Solution Approach 1:
The feedback loop is segmented into two separate loops: a first feedback path that provides fast transient response and a second feedback path that ensures stability. The first feedback path includes a first amplifier and transconductance stage that directly respond to output voltage changes, while the second feedback path includes a second amplifier and transimpedance stage that provide overall regulation. This segmentation allows each loop to be optimized for its specific function, achieving fast transient response without excessive complexity.
2Speed
If larger output capacitors are used to improve transient response, then the transient response performance is improved, but the bill of material cost increases
Solution Approach 1:
The patent implements a dual feedback mechanism where the first feedback path provides rapid response to transient changes by directly sensing output voltage changes and adjusting the pass transistor accordingly. The second feedback path provides overall voltage regulation. This enhanced feedback control allows the system to maintain stability with smaller output capacitors, as the active feedback compensation replaces the need for large passive capacitance to stabilize the output during transient events.
3Speed
If larger output capacitors are used to improve transient response, then the transient response performance is improved, but the die area increases
Solution Approach 1:
The dual feedback loop architecture with active compensation circuits enables the use of smaller output capacitors, thereby reducing the required die area. The first amplifier and transconductance stage provide rapid transient response without requiring large capacitive storage, as the active feedback mechanism dynamically adjusts the pass transistor to compensate for transient changes. This approach trades circuit complexity for reduced passive component size and die area.
4Use of energy by moving object
If conventional LDO regulators are used, then the circuit simplicity is maintained, but the efficiency deteriorates when driving digital loads
Solution Approach 1:
The patent implements dynamic control through the transconductance stage and transimpedance stage that can rapidly adjust the pass transistor conduction state in response to transient changes. The first amplifier provides high-gain control for fast response, while the second amplifier ensures stability. This dynamic adjustment capability allows the regulator to efficiently handle the rapid current changes characteristic of digital loads, minimizing power loss during transient events while maintaining overall circuit stability.
Data Source
AI summary
Certain aspects of the present disclosure generally relate a dual feedback loop regulator. For example, the regulator may include a first amplifier having an output coupled to an output node of the regulator, the output node further coupled to a first feedback path and a second feedback path of the regulator. A first input of a second amplifier may be coupled to the first feedback path and a second input of the second amplifier may be coupled to a reference path. The regulator may also include a transconductance stage having a first transistor and a first current source, the first transistor and the current source coupled to the first feedback path and the second feedback path, and a transimpedance stage coupled to the transconductance stage and an input of the first amplifier.