Switched-Capacitor Charge Combining for Low-Noise, Low-Power Circuits
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Solution Overview
Problem
Existing analog signal-processing circuits, particularly switched-capacitor circuits, face challenges in achieving low noise and low power consumption while maintaining accuracy and robustness to environmental variations, as they often compromise between noise reduction and power consumption.
Innovation Solution
The proposed solution involves a signal-processing circuit with multiple capacitors that operate in distinct phases to manage charge storage and combination, ensuring a high degree of settling in one phase for accuracy and reducing noise bandwidth in another phase for low power consumption, thereby achieving a balance between noise reduction and power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the amplifier circuit operates continuously with high power consumption to reduce noise, then the noise level is reduced, but the power consumption increases
Solution Approach 1:
The amplifier circuit operates in periodic phases: during the first phase it settles with negative feedback to ensure accuracy, during the second phase it operates open-loop to reduce noise bandwidth. This periodic switching allows the circuit to achieve low noise performance without continuous high power consumption, as the amplifier is not constantly operating at full gain with full bandwidth.
Solution Approach 2:
The circuit changes operational parameters between phases: in the first phase the amplifier operates with negative feedback providing high gain and accuracy, while in the second phase it operates open-loop with reduced gain and reduced noise bandwidth. This parameter switching allows optimization of both noise performance and power consumption at different times in the signal processing cycle.
2Measurement precision
If the amplifier settles completely in the first phase to ensure accuracy, then the accuracy and robustness are improved, but the time available for noise reduction in the second phase is reduced
Solution Approach 1:
The amplifier performs partial settling in the first phase rather than complete settling. The negative feedback ensures sufficient accuracy for the charge transfer operation, but the settling is intentionally left incomplete to preserve time for the second phase. The open-loop operation in the second phase then provides noise reduction benefits during the remaining time, achieving a practical balance between accuracy and noise performance.
3Device complexity
If switched-capacitor circuits use traditional single-phase operation to reduce complexity, then the device complexity is reduced, but the ability to achieve both low noise and low power consumption is compromised
Solution Approach 1:
The signal processing operation is segmented into two distinct phases: first phase for accurate charge transfer with negative feedback, and second phase for noise reduction with open-loop operation. This temporal segmentation allows the circuit to achieve both low noise and low power consumption characteristics that would be difficult to achieve in a traditional single-phase continuous operation mode, without significantly increasing overall circuit complexity.
Data Source
AI summary
Herein disclosed are multiple embodiments of a signal-processing circuit that may be utilized in various circuits, including conversion circuitry. The signal-processing circuit may receive an input and produce charges on multiple different capacitors during different phases of operation based on the input. The charges stored on two or more of the multiple different capacitors may be utilized for producing an output of the signal-processing circuit, such as by combing the charges stored on two or more of the multiple different capacitors. Utilizing the charges on the multiple different capacitors may provide for a high level of accuracy and robustness to variations of environmental factors, and/or a low noise level and power consumption when producing the output.