RF Amplifier Switching Circuit With Shared Bias to Cut Transfer Loss
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Solution Overview
Problem
The existing amplifier circuits for radio-frequency signals face issues with increased transfer loss due to on-resistance of semiconductor switches and off-leak current, which can lead to signal degradation and increased size of the circuit.
Innovation Solution
A miniaturized amplifier circuit is designed with a switching circuit that includes a transistor with a substrate bias voltage supply, allowing for direct-current conduction and reducing the number of bias circuits, thereby minimizing the circuit size while maintaining low signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If additional circuits are incorporated to reduce on-resistance and off-leak current of the semiconductor switch, then transfer loss and off-leak current are reduced, but the size of the amplifier circuit increases
Solution Approach 1:
The bias circuit is merged with the switching circuit by sharing common terminals. The source terminal of the switching transistor and the drain terminal of the amplifier transistor serve as common connection points, eliminating the need for separate bias circuits for each transistor. This integration reduces the overall circuit size while maintaining the ability to control both on-resistance and off-leak current through coordinated biasing.
Solution Approach 2:
The bias circuit is designed to simultaneously control both the switching transistor and the amplifier transistor. By using shared terminals and a unified biasing approach, the same bias circuit performs multiple functions: controlling the on-resistance of the switching transistor and managing the off-leak current of both transistors, thereby reducing circuit complexity and size.
2Object-generated harmful factors
If additional circuits are incorporated to reduce on-resistance and off-leak current of the semiconductor switch, then off-leak current is reduced, but the size of the amplifier circuit increases
Solution Approach 1:
The bias circuits for the switching transistor and amplifier transistor are merged into a single integrated bias circuit. The shared source terminal of the switching transistor and drain terminal of the amplifier transistor allow the same bias circuit to control both devices, reducing overall circuit size while effectively managing off-leak current through coordinated bias voltage control.
Solution Approach 2:
The bias circuit utilizes the inherent electrical connections between transistors to create a feedback mechanism. By controlling the bias voltage at shared terminals, the circuit automatically adjusts to minimize off-leak current in both transistors, achieving effective leak current control without requiring additional separate control circuits.
3Productivity
If the semiconductor switch is used to transfer radio-frequency signals, then signal transfer is enabled, but transfer loss increases due to on-resistance
Solution Approach 1:
The bias circuit dynamically adjusts the operating parameters of the switching transistor to optimize performance. By controlling the gate-source voltage and utilizing the shared source terminal, the bias circuit maintains the switching transistor in an optimal operating state that minimizes on-resistance during signal transfer, thereby reducing transfer loss while preserving signal transfer capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively reduces the transfer loss and off-leak current, enabling the amplifier circuit to transfer radio-frequency signals with low loss and maintaining receive sensitivity, while also miniaturizing the communication device.
Implementation Method 1
a first switch including a transistor that has a first control terminal and a first substrate of a first conductivity type, the first switch being configured to alternate connection and disconnection between a first terminal and a second terminal in response to a voltage applied to the first control terminal
Implementation Method 2
The bias circuit, the first terminal, and the first substrate are coupled for direct-current conduction
Data Source
AI summary
An amplifier circuit includes a low-noise amplifier configured to amplify a radio-frequency signal, a switching circuit coupled between the low-noise amplifier and an antenna connection terminal, and a bias circuit configured to supply a direct-current bias voltage to the low-noise amplifier 11. The switching circuit includes a terminal coupled to the low-noise amplifier and a terminal coupled to the antenna connection terminal, and a transistor including a gate terminal and a p-type first substrate, configured to alternate the connection and disconnection between the terminals and in response to a voltage applied to the gate terminal. The bias circuit, the terminal, and the first substrate are coupled for direct-current conduction.