GM Amplifier Circuit With Offset Correction for Wide-Band Sensor Signals
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Solution Overview
Problem
Existing amplifier circuits face challenges in accurately amplifying weak signals from sensors while minimizing noise interference and maintaining a compact chip size, often requiring additional circuitry for phase compensation which increases size and cost.
Innovation Solution
The proposed amplifier circuit employs a configuration with GM amplifiers, capacitive elements, and selector circuits to perform differential amplification and real-time offset correction, eliminating the need for phase compensation circuits, thereby achieving high accuracy and wide-band operation without increasing chip size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase compensation circuits are added to improve amplification accuracy, then measurement precision is improved, but device complexity and chip size increase
Solution Approach 1:
The patent extracts and eliminates the phase compensation circuit from the amplifier design, achieving high-frequency accurate amplification without this traditional component. The GM amplifier structure inherently provides the needed phase characteristics, making separate phase compensation unnecessary and reducing overall circuit complexity.
Solution Approach 2:
The patent changes the operating parameters of the GM amplifier, specifically operating it in an overdrive condition where the tail current is larger than the sum of bias currents. This parameter change enables the amplifier to maintain accurate gain at high frequencies without requiring phase compensation circuits.
2Measurement precision
If additional circuitry is added for phase compensation, then amplification accuracy is improved, but chip size increases
Solution Approach 1:
The patent removes the phase compensation circuit entirely from the design, achieving accurate high-frequency amplification through the GM amplifier's inherent characteristics and proper biasing. This extraction eliminates the additional chip area that would be required for phase compensation components.
3Area of stationary object
If conventional amplifier circuits are used, then chip size is reduced, but noise interference increases and amplification accuracy deteriorates
Solution Approach 1:
The patent changes the operating parameters by using a GM amplifier in overdrive condition with specific current relationships (tail current larger than sum of bias currents). This parameter change enables compact design while maintaining low noise and high accuracy through the amplifier's inherent high-frequency characteristics and proper biasing.
4Measurement precision
If phase compensation circuits are added, then amplification accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the phase compensation circuit, reducing the total component count and circuit complexity. This directly lowers manufacturing cost while maintaining amplification accuracy through the GM amplifier's inherent characteristics and simplified circuit architecture.
Data Source
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AI summary
According to an embodiment, there is provided an amplifier circuit (1, 301, 401) including a first capacitive element (C1), a first GM amplifier (4), and a second GM amplifier (5). The first GM amplifier includes a first input node, a second input node, and an output node. The output node is connected to one end of the first capacitive element. The second GM amplifier includes a first input node, a second input node, and an output node. The output node is connected to one end of the first capacitive element and the second input node.