Gain Modulation Circuit With Feedback-Controlled Linear Region
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Solution Overview
Problem
Existing gain modulation circuits suffer from reduced linearity when the absolute difference between input voltages increases, leading to a smaller gain and worse efficiency.
Innovation Solution
A gain modulation circuit design that includes a load circuit, differential circuit, current source, resistor, and detector circuit, where the detector circuit generates a detection signal to adjust the turned-on degree of a transistor, thereby adjusting the linear region and maintaining gain even with larger input voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the absolute difference between input voltages increases, then the gain decreases, but the linearity deteriorates
Solution Approach 1:
The detector circuit monitors the input voltage difference and generates a detection signal that feeds back to adjust the turned-on degree of the first transistor. This feedback mechanism dynamically compensates for gain changes, maintaining both linearity and gain across varying input voltage differences.
Solution Approach 2:
The circuit transitions from a static configuration to a dynamic one where the first transistor's conductance state is continuously adjusted based on the detection signal. This dynamic adjustment allows the circuit to adapt to varying input conditions, preserving linearity while maintaining gain.
2Productivity
If the gain is increased to improve efficiency, then the output performance improves, but the linear region shrinks
Solution Approach 1:
The detection signal dynamically changes the parameter (turned-on degree) of the first transistor based on the input voltage difference. This parameter adjustment optimizes the circuit's operating point, expanding the linear region while maintaining high gain and efficiency across different operating conditions.
Data Source
AI summary
A gain modulation circuit includes a load circuit, a differential circuit, a current source, a resistor, a first transistor, and a detector circuit. The load circuit is configured to receive a supply voltage. The differential circuit is coupled to the load circuit. The differential circuit and the load circuit are configured to generate a pair of output voltages according to a pair of input voltages and the supply voltage. The current source is coupled to the differential circuit. The resistor is coupled to the differential circuit and the current source. The first transistor is coupled to the differential circuit. The detector circuit is configured to generate a detection signal according to the pair of input voltages. A turned-on degree of the first transistor is adjusted based on the detection signal, to adjust a linear region of the gain modulation circuit.