RF Power Amplifier Capacitive Coupling for Low-Loss Power Control
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Solution Overview
Problem
Conventional radio frequency circuits face issues with power loss and increased wiring length due to coupling directivity in the coupling line technology used for power control.
Innovation Solution
The radio frequency circuit employs a coupling circuit with transistors in a partial cut-off state to achieve capacitive coupling, replacing the conventional coupling line and allowing for programmable loopback power control by adjusting the cut-off degree of transistors with control voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a coupling line is used for power control in radio frequency circuits, then power control functionality is achieved, but power loss increases and wiring length increases
Solution Approach 1:
The patent merges the coupling circuit functionality directly into the radio frequency circuit by using transistors that are already present in the circuit. The transistors serve dual purposes: as switching elements for power control and as coupling elements for signal transmission, eliminating the need for separate coupling lines and reducing overall wiring length.
Solution Approach 2:
The transistors in the radio frequency circuit are made multi-functional by enabling them to operate in a partial cut-off state that provides capacitive coupling. This allows the same transistor components to perform both power control switching and signal coupling functions, thereby reducing the need for additional dedicated coupling lines and associated wiring.
2Reliability
If a coupling line is used for power control, then power control is achieved, but coupling directivity problems occur
Solution Approach 1:
The patent changes the operating parameter of the transistors by setting them to a partial cut-off state rather than fully on or fully off. This parameter change enables the transistors to exhibit capacitive coupling characteristics, improving coupling directivity without requiring additional coupling circuit components.
3Volume of stationary object
If conventional coupling line technology is used, then power control functionality is provided, but the volume of integrated circuit packages increases
Solution Approach 1:
The patent combines the power control and signal coupling functions into the existing transistor structures within the integrated circuit. By eliminating separate coupling lines and using the transistors' inherent capacitive effects in a partial cut-off state, the overall circuit footprint is reduced, leading to smaller integrated circuit package volumes.
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
This solution reduces power loss and wiring length, enhances coupling directivity, and provides flexible pin configuration, enabling efficient power control and reducing the volume of integrated circuit packages.
Implementation Method 1
the at least one transistor provides a coupling signal at the second coupling terminal through capacitive coupling
Data Source
AI summary
A radio frequency circuit is provided. The radio frequency circuit includes a first terminal, a second terminal, a power amplifier, and a coupling circuit. The power amplifier is coupled between the first terminal and the second terminal. The power amplifier is configured to receive a first signal. The coupling circuit includes a first coupling terminal, a second coupling terminal, and at least one transistor. The first coupling terminal is coupled to the power amplifier and the second terminal. The at least one transistor is connected in series between the first coupling terminal and the second coupling terminal. In a coupling mode, the at least one transistor is in an at least partial cut-off state, and the at least one transistor provides a coupling signal at the second coupling terminal through capacitive coupling. The first signal is controlled according to the coupling signal.