Amplifier Bypass Circuit for Linearity Under High Input Signals
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Solution Overview
Problem
In wireless communication amplifiers, when the input signal intensity is high, unexpected conduction occurs across semiconductor junctions during the bypass mode, affecting the linearity of the bypass circuit and reducing operational performance.
Innovation Solution
The amplifier design includes a cascode structure with specific transistor configurations and bias circuits that turn off transistors to prevent conduction and increase reverse-bias, ensuring the signal is routed through a bypass path without affecting the linearity, using transistors like N-type MOSFETs and P-type MOSFETs to manage voltage levels and impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the amplifier is switched to bypass mode to reduce power consumption, then power consumption is reduced, but unexpected conduction occurs on semiconductor junctions affecting linearity
Solution Approach 1:
The patent extracts the problematic semiconductor junctions from the signal path by introducing a bypass circuit that routes the signal around the amplifier's internal transistors when operating in bypass mode, eliminating the source of unexpected conduction while maintaining the power savings
Solution Approach 2:
The patent introduces an intermediary bypass circuit with dedicated switching transistors that mediates between the amplifier and the signal path, allowing the amplifier to be disconnected from the signal flow in bypass mode without causing conduction issues, thus preserving linearity while reducing power consumption
2Loss of energy
If the switch is turned off to output the input signal via the bypass circuit, then power consumption is reduced, but linearity of the bypass circuit is affected
Solution Approach 1:
The patent applies local quality by designing the bypass circuit with specific transistor configurations (such as using transistors with appropriate W/L ratios and biasing) that are optimized for linear operation in the bypass mode, ensuring that the local characteristics of the bypass path maintain signal linearity while still achieving power reduction
Data Source
AI summary
An amplifier includes an input terminal for receiving an input signal, an output terminal for outputting an output signal, a first transistor, a second transistor having a first terminal coupled to a second terminal of the first transistor, a third transistor having a first terminal coupled to a second terminal of the second transistor, a capacitor coupled between a control terminal and a second terminal of the third transistor, a bias circuit coupled to the first terminal of the third transistor for providing a bias voltage to the third transistor, a fourth transistor having a first terminal coupled to the input terminal and a second terminal coupled to the output terminal for providing a bypass path, and a fifth transistor having a first terminal coupled to the first terminal of the first transistor and a second terminal coupled to the output terminal.