Chopper Amplifier Offset Correction for Fast Saturation Recovery
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Solution Overview
Problem
Chopper amplifier circuits face challenges in recovering from saturation states caused by excessive input signals, leading to prolonged delays in returning to a normal operating state due to the limitations of negative feedback control and the slow response of filter circuits, particularly integration circuits with large time constants.
Innovation Solution
The amplifier circuitry includes a main amplifying circuit with negative feedback, an offset correction circuit using a chopper amplifier and filter circuit, and a control circuit that detects abnormal states and resets the integration circuit to a default state when the input levels return to normal, facilitating quicker resumption of integration and negative feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an integration circuit with a large time constant is used to remove high-frequency components, then filtering performance is improved, but the recovery time from saturation state increases
Solution Approach 1:
The control circuit detects saturation state in advance and proactively resets the integration circuit before the natural recovery process begins. By detecting when the operational amplifier output reaches saturation levels and actively clearing the integration capacitor voltage, the system prepares for faster recovery without compromising the filtering performance during normal operation.
Solution Approach 2:
The invention creates a control copy mechanism that monitors the output signal and generates control signals to reset the integration circuit. This control circuit acts as a separate monitoring system that copies the output signal state and uses it to trigger reset operations, enabling independent control of the integration circuit's recovery process without affecting the main signal path.
2Measurement precision
If negative feedback control is used for offset correction, then accuracy is improved, but response speed during saturation recovery deteriorates
Solution Approach 1:
The control circuit serves as an intermediary mechanism that bridges the conflict between negative feedback control and fast recovery. It monitors the saturation state and actively intervenes by resetting the integration circuit, thereby mediating between the need for accurate offset correction through negative feedback and the need for rapid recovery from saturation without relying solely on the slow natural response of the feedback loop.
Data Source
AI summary
Amplifying circuitry configured such that when a detection circuit detects an abnormal state in which the level of signals input to a main amplifying circuit exceeds a normal range, a control circuit sets the state of integration of signals in the integration circuit to a default state. When the detection circuit detects the abnormal state and then detects that an operating state returns to a normal state in which the level of signals input to the main amplifying circuit is included in the normal range, the control circuit cancels the setting of the default state in the integration circuit.