Replica-Controlled Variable Gain Amplifier for Temperature-Stable Gain
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Solution Overview
Problem
Variable gain amplifiers experience gain offset due to temperature changes, leading to incorrect signal amplitudes in signal processing applications.
Innovation Solution
A variable gain amplifier device incorporating a variable gain amplifier circuitry and a control voltage generation circuitry that simulates circuit portions to generate a control voltage, maintaining a fixed gain by adjusting resistance values based on input signals and setting voltages, thereby compensating for temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the variable gain amplifier uses a conventional gain control method, then the device complexity is low, but the gain stability deteriorates due to temperature changes
Solution Approach 1:
The patent creates a replica of the variable gain amplifier circuit that copies the temperature-dependent characteristics. This replica circuit generates a control voltage that compensates for temperature effects in the main amplifier, allowing the system to maintain stable gain without requiring complex external temperature sensing and compensation mechanisms.
Solution Approach 2:
The patent replaces mechanical or external temperature compensation mechanisms with an electrical circuit solution. By using voltage-controlled resistors and operational amplifiers to generate compensating control voltages, the system achieves temperature compensation through electrical fields rather than mechanical adjustments or external sensors.
2Reliability
If the variable gain amplifier compensates for temperature effects using external sensors and control circuits, then the gain stability improves, but the device complexity increases
Solution Approach 1:
The patent merges the temperature compensation function with the existing variable gain amplifier circuit by integrating a replica circuit that mirrors the main amplifier's characteristics. This combination allows the compensation mechanism to be inherently tied to the amplifier's operation, eliminating the need for separate external temperature sensors and independent control systems.
Solution Approach 2:
The replica circuit automatically generates the appropriate control voltage based on its own temperature-dependent characteristics, which mirror those of the main amplifier. This self-service mechanism eliminates the need for external temperature sensing and manual compensation adjustments, reducing overall system complexity while maintaining gain stability.
Data Source
AI summary
A variable gain amplifier device includes a variable gain amplifier circuitry and a control voltage generating circuitry. The variable gain amplifier circuitry is configured to amplify input signals to generate output signals, wherein the variable gain amplifier circuitry includes a gain setting circuit that is configured to set a gain of the variable gain amplifier circuitry according to a control voltage. The control voltage generation circuitry is configured to simulate at least one circuit portion of the variable gain amplifier circuitry, in order to generate the control voltage according to the input signals and a setting voltage.