Reference Buffer Circuit Segmentation for Low Voltage Stability
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Solution Overview
Problem
Conventional reference buffer circuits face challenges in operating under low supply voltage while maintaining high-resolution and low power consumption, as they often require high output impedance and wide bandwidth, leading to increased noise and power consumption.
Innovation Solution
The proposed reference buffer circuit incorporates a combination of closed-loop and open-loop branches with MOS transistors and tracking circuits, allowing the reference voltage to track input voltages effectively, reducing output impedance, and enabling operation under low supply voltage without limiting the voltage swing, thus minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a closed-loop reference buffer circuit is used to rapidly stabilize reference voltage, then the output impedance is reduced and stability is improved, but power consumption and noise increase due to wide bandwidth requirements
Solution Approach 1:
The reference buffer circuit is divided into two separate branches: a closed-loop branch for stability and an open-loop branch for low power consumption. Each branch independently provides reference voltage to the ADC, allowing the system to achieve both stability and low power consumption without requiring wide bandwidth in a single amplifier.
2Speed
If a closed-loop reference buffer circuit operates at high frequency to rapidly stabilize reference voltage, then response speed is improved, but output impedance must be very low which increases power consumption
Solution Approach 1:
The circuit is segmented into closed-loop and open-loop branches that operate in parallel. The closed-loop branch handles transient stabilization while the open-loop branch maintains steady-state operation, distributing the speed and power requirements across different branches rather than demanding both from a single high-frequency amplifier.
3Use of energy by moving object
If open-loop reference buffer circuit operates under low supply voltage to reduce power consumption, then power efficiency is improved, but voltage swing is limited
Solution Approach 1:
The reference buffer is segmented into two branches that can operate independently or together. The open-loop branch operates efficiently at low supply voltage for normal conditions, while the closed-loop branch provides additional voltage swing capability when needed, giving the system adaptability to different voltage requirements without sacrificing power efficiency.
Data Source
AI summary
A reference buffer circuit is disclosed, providing a reference voltage at an output node and comprising a closed-loop branch comprising an amplifier and first and second MOS transistors and an open-loop branch comprising third and fourth MOS transistors and a tracking circuit. The first MOS transistor has a gate coupled to an output terminal of the amplifier and a source coupled to a negative input terminal of the amplifier. The second MOS transistor is coupled to the source of the first MOS transistor. The third MOS transistor has a gate coupled to the output terminal and a source coupled to the output node. The fourth MOS transistor has a drain coupled to the source of the third MOS transistor. A gate voltage of the fourth MOS transistor tracks a drain voltage of the third MOS transistor through the tracking circuit.