Bandgap Pre-Regulator Circuit for Low Quiescent Current
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Solution Overview
Problem
Existing low-dropout regulators (LDOs) with nano power pre-regulators have high quiescent current consumption, particularly in off-mode, which contributes significantly to total current consumption, and require large silicon area due to complex circuits involving components like Zener diodes and resistors.
Innovation Solution
A high input voltage pre-regulator circuit with reduced quiescent consumption and fewer components, utilizing a Caprio cell structure and current generators to minimize silicon area and power consumption, featuring a simplified architecture with a startup circuit, current generator, and voltage multiplier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If known architectures with Zener diodes, resistors, and current generators are used to reduce bias current, then bias current is reduced, but silicon area footprint increases
Solution Approach 1:
The patent combines multiple functions into a single integrated circuit block that performs voltage regulation, bias current generation, and protection functions simultaneously, eliminating the need for separate Zener diodes, resistors, and current generator circuits, thereby reducing silicon area while maintaining low bias current
Solution Approach 2:
The proposed circuit architecture uses universal components that serve multiple purposes: the main transistor provides both voltage regulation and bias current control, while feedback mechanisms simultaneously stabilize voltage and minimize quiescent current, achieving multiple goals with fewer components
2Measurement precision
If complex circuits with multiple components are used to achieve precise voltage regulation, then voltage regulation precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage is monitored and fed back to the control terminal of the main transistor, automatically adjusting the transistor's operation to maintain precise voltage regulation without requiring complex external control circuits
Solution Approach 2:
The circuit is designed to be self-regulating, where the transistor automatically adjusts its conduction based on the feedback signal, and the bias current network self-adjusts to maintain optimal operating conditions, eliminating the need for complex external control circuits
Data Source
AI summary
A circuit includes a supply node receiving a supply voltage; an output node providing a regulated voltage; startup circuitry coupled to the supply node; current generator circuitry coupled to the startup circuitry and producing a current; a bandgap node coupled to bandgap circuitry to receive a bandgap voltage; multiplier circuitry coupled to the bandgap node and the current generator circuitry to receive and apply scaling to the current; a first transistor providing a threshold voltage drop across the first and second transistor nodes; a first resistive element interposed between the first transistor and the bandgap node; a second resistive element coupled between ground and the second node of the first transistor; and an operational amplifier receiving a pre-regulated voltage as a function of the bandgap voltage, the threshold voltage across the first transistor, and a voltage drop across the first and second resistive elements.