Multi-Gain Stage Offset Calibration Without Extra Signal Paths
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Solution Overview
Problem
Conventional multi-gain systems require additional paths and control circuits for offset voltage calibration, increasing complexity and manufacturing costs, and causing loading effects that affect performance.
Innovation Solution
A multi-gain stage circuit that calculates offset voltages using output signals without additional paths, utilizing a gain control circuit and calibration circuit to adjust gain values and generate calibration signals for each stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional paths and control circuits are added for offset voltage calibration, then calibration capability is improved, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent merges the calibration function with the existing multi-gain stage circuit by having the calibration circuit share the same signal path and gain stages. The calibration circuit utilizes the output signals from the gain stages to calculate offset voltages, eliminating the need for separate calibration paths and control circuits.
Solution Approach 2:
The gain stages serve dual purposes: they perform signal amplification during normal operation and provide output signals for offset voltage calculation during calibration. The same circuit components are used for both signal processing and calibration functions, reducing overall system complexity.
2Reliability
If additional paths are added for offset voltage calibration, then calibration capability is improved, but manufacturing costs increase
Solution Approach 1:
The calibration function is merged into the existing circuit architecture, allowing a single integrated circuit to perform both signal amplification and offset voltage calibration. This reduces the number of discrete components needed and simplifies the manufacturing process.
Solution Approach 2:
The calibration circuit uses the output signals from the gain stages themselves to calculate and correct offset voltages, rather than requiring external calibration equipment or additional sensing paths. The system calibrates itself using its own operational signals.
3Reliability
If additional paths are added for offset voltage calibration, then calibration capability is improved, but loading effects on the original multi-gain stage increase
Solution Approach 1:
The calibration circuit introduces virtual ground nodes as intermediaries to isolate the calibration measurement process from the signal path. These virtual grounds allow the calibration circuit to sample and calculate offset voltages without creating direct loading effects on the gain stages during normal signal amplification.
Solution Approach 2:
The calibration process is performed as a preliminary step before normal signal amplification. By calculating and correcting offset voltages first, the system prepares the gain stages for optimal operation without the need for continuous additional paths that would create ongoing loading effects.
Data Source
AI summary
A multi-gain stage circuit is arranged to receive an input signal to generate an output signal, and includes a first gain stage, a second gain stage, a gain control circuit, and a calibration circuit. The second gain stage is connected in series with the first gain stage, and the second gain stage generates the output signal. The gain control circuit controls the first gain stage to have a first gain value such that the output signal is regarded as a product of a gain value of the second gain stage and an offset voltage of the second gain stage. The calibration circuit calculates the offset voltage of the second gain stage according to the output signal, and calibrates the second gain stage according to the offset voltage of the second gain stage calculated by the calibration circuit.