Amplifier Common-Mode Voltage Control Without Extra Transistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing amplifiers face issues with common mode voltage deviation from preset values, leading to output dynamic range compression and reduced operating voltage, necessitating a solution to adjust the common-mode voltage without adding additional transistors.
Innovation Solution
The amplifier design incorporates p-type and n-type transistors cascoded between reference voltages, with capacitors and control circuits to adjust the common mode voltage by controlling the conduction of transistors based on output signals and target voltage, without requiring additional transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional transistors are cascoded to adjust common-mode voltage, then common-mode voltage control is improved, but device complexity increases
Solution Approach 1:
The patent changes the operating parameters of existing transistors (gate voltages, conduction degrees) rather than adding more transistors. The control circuit adjusts the conduction degree of existing input transistors to regulate output common-mode voltage, thereby avoiding additional transistor cascoding while achieving effective voltage control.
2Use of energy by moving object
If operating voltage is reduced to advance process, then power consumption is reduced, but common-mode voltage stability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the control circuit monitors the output common-mode voltage and dynamically adjusts the conduction degree of input transistors accordingly. This feedback loop maintains common-mode voltage stability even when operating voltage is reduced, enabling low-power operation without sacrificing voltage control reliability.
Data Source
AI summary
The present application discloses an amplifier and a method for controlling a common mode voltage thereof. The method includes: generating a control signal according to a positive-terminal input signal, a negative-terminal input signal and a target common mode voltage; and coupling the controlling signal to a first terminal of a positive-terminal capacitor and a first terminal of a negative-terminal capacitor, to adjust degree of conduction of a positive-terminal p-type transistor and degree of conduction of a negative-terminal p-type transistor, or to adjust degree of conduction of a positive-terminal n-type transistor and degree of conduction of a negative-terminal n-type transistor, thereby changing a common mode voltage.