Offset-Buffer Voltage Regulator for Low-Headroom N-Type LDOs
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Solution Overview
Problem
Conventional voltage regulator designs, such as N-type LDO regulators, face challenges in achieving optimal power and performance across a range of voltage targets and load currents, particularly due to limitations in headroom for amplifier signal swings and the need for multiple voltage rails.
Innovation Solution
The introduction of a programmable voltage regulator topology that includes an induced offset voltage buffer between the error amplifier and the N-type pass transistor, allowing for level shifting and biasing adjustments to optimize the quiescent point and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional N-type LDO regulator design is used, then the regulator can provide stable output voltage, but it requires multiple voltage rails and has limited headroom for amplifier signal swings
Solution Approach 1:
An offset-induced voltage buffer is introduced as an intermediary component between the error amplifier and the N-type pass transistor. This buffer performs level-shifting to provide adequate headroom for the error amplifier signal swings while operating from a single voltage rail, thereby eliminating the need for multiple voltage rails and reducing device complexity
2Adaptability or versatility
If voltage targets are adjusted to meet different application needs, then the regulator can serve multiple applications, but the voltage swing saturates and amplifier gain degrades
Solution Approach 1:
The offset-induced voltage buffer acts as a mediator that decouples the error amplifier from the output voltage target variations. By providing level-shifting and isolation, it allows the error amplifier to maintain its signal swing headroom and gain characteristics regardless of the specific voltage target, enabling adaptable voltage regulation across different applications
Solution Approach 2:
The voltage regulation function is segmented into distinct stages: the error amplifier stage for error detection and amplification, and the offset-induced voltage buffer stage for level-shifting and output drive. This segmentation allows each stage to be optimized independently, maintaining amplifier gain while achieving different voltage targets through the buffer's level-shifting capability
3Use of energy by moving object
If low voltage supplies are used to reduce power consumption, then power efficiency improves, but headroom for amplifier signal swings is limited
Solution Approach 1:
The offset-induced voltage buffer serves as an intermediary that enables the error amplifier to operate from low voltage supplies while maintaining adequate signal swing headroom. The buffer absorbs the voltage level adjustments needed for proper amplifier operation, allowing the amplifier to run at lower voltages for reduced power consumption without sacrificing signal swing capability
Solution Approach 2:
The offset voltage in the voltage buffer is adjusted as a controllable parameter to provide the necessary level-shifting for different output voltage targets. This parameter adjustment allows the amplifier to maintain optimal operating conditions with adequate headroom while the overall regulator operates from low voltage supplies, achieving both low power consumption and sufficient signal swing capability
Data Source
AI summary
Disclosed are voltage regulator circuits and techniques. Some embodiments employ an offset induced buffer to drive an N-type drive transistor.