Flipped Voltage Follower Reference Circuit for Low-Noise Output
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Solution Overview
Problem
Existing reference voltage generators often introduce noise through buffering, which negatively affects the performance of electronic circuits and devices that rely on these voltages.
Innovation Solution
A reference voltage generator circuit utilizing a first flipped voltage follower, a control signal filter, a bias filter, and a second flipped voltage follower to generate a low-noise reference voltage by filtering control and bias signals, thereby reducing noise and improving voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If voltage and current buffering is added to the reference voltage generator, then the reference voltage can be used for ADC or PLL circuits, but unwanted noise is introduced in the reference voltage
Solution Approach 1:
The reference voltage generator is divided into multiple independent stages: a first flipped voltage follower for initial voltage generation, a control signal filter for noise removal, a second flipped voltage follower for buffered output, and optional bias filters. Each stage performs a specific function, allowing the system to provide buffered output for ADC/PLL usage while isolating and removing noise at intermediate stages through filtering.
2Object-generated harmful factors
If filtering stages are added to reduce noise, then noise in the reference voltage is reduced, but device complexity increases
Solution Approach 1:
Filter circuits are introduced as intermediary components between the first and second flipped voltage followers. These filters act as mediators that selectively remove noise frequencies from control and bias signals without significantly affecting the overall voltage generation function. The filters are strategically placed to eliminate noise at critical points in the signal path, achieving noise reduction with minimal additional complexity.
Data Source
AI summary
A reference voltage generator is disclosed. The reference voltage generator may include an operational transconductance amplifier (OTA), a bias generator, a first flipped voltage follower, a bias filter, a control signal filter, and a second flipped voltage follower. The OTA and the first flipped voltage follower may generate a control signal based on a reference voltage and a bias voltage from the bias generator. The bias filter may filter the bias voltage and the control signal filter may filter the control signal. The second flipped voltage follower may generate the output voltage based on the filtered bias voltage and the filtered control signal.