Multi-Stage Voltage Reference Circuit for Low Noise Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage reference circuits face challenges in achieving high precision and low noise while maintaining low quiescent current, making them unsuitable for applications requiring precise output voltage with small sensed signals, especially in portable or battery-powered devices.
Innovation Solution
The proposed circuit design incorporates a current mirror circuit with multiple stages and a voltage divider network, utilizing transistors with different threshold voltages to generate a higher output voltage without increasing noise, thereby reducing the need for resistor scaling and maintaining low quiescent current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltage reference circuits are used, then they can provide stable voltage reference, but they generate excessive noise that degrades measurement precision
Solution Approach 1:
The voltage reference circuit is divided into multiple independent stages (first stage, second stage, third stage) with distinct functions. Each stage processes the voltage reference signal separately, allowing noise filtering to be applied at specific stages without affecting the overall stability mechanism. The first stage generates the basic reference voltage, the second stage buffers it, and the third stage provides final regulation with noise filtering.
Solution Approach 2:
A buffer stage is introduced as an intermediary between the voltage reference generation stage and the output stage. This buffer stage isolates the sensitive reference generation circuit from loading effects and noise, allowing the reference voltage to be transferred with high precision and low noise to the output stage.
2Measurement precision
If resistor values are increased to reduce thermal noise, then noise is reduced, but the circuit complexity and scaling requirements increase
Solution Approach 1:
The circuit uses multiple voltage reference stages with different voltage levels (1.25V, 2.5V, 5V) instead of relying on single high-value resistors for noise reduction. By changing the voltage parameters and using staged voltage multiplication, the circuit achieves low noise performance without requiring extreme resistor value scaling, thus reducing device complexity.
3Reliability
If high precision voltage reference is achieved through conventional designs, then voltage stability is improved, but quiescent current consumption increases
Solution Approach 1:
The circuit employs dynamic current management where each stage is designed to operate at optimized current levels. The buffer stage uses high input impedance to minimize current draw from the reference generation stage, while the output stage dynamically adjusts its current based on loading conditions. This dynamic operation maintains voltage stability while minimizing overall quiescent current consumption.
Solution Approach 2:
The circuit uses periodic refresh cycles for the voltage reference capacitors, where the reference voltage is updated at controlled intervals rather than continuously. This periodic action maintains voltage stability over time while significantly reducing the average current consumption compared to continuous regulation schemes.
Data Source
AI summary
In described examples, a circuit includes a current mirror circuit. A first stage is coupled to the current mirror circuit. A second stage is coupled to the current mirror circuit and to the first stage. A voltage divider network is coupled to the second stage. The circuit includes an output transistor having first and second terminals, in which the first terminal of the output transistor is coupled to the first stage, and the second terminal of the output transistor is coupled to the voltage divider network.