RF Switch Circuit With Mode-Specific Off Voltages for Fast Switching
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Solution Overview
Problem
Radio frequency (RF) switch circuits in communication devices face challenges in rapidly switching between transmitting and receiving modes while maintaining linearity and signal power, especially in achieving faster switching operations with improved performance and noise resistance.
Innovation Solution
The RF switch circuit design includes a first switch with series and shunt transistors between a transmitting port and an antenna port, and a second switch with series and shunt transistors between the antenna port and a receiving port, controlled by a switch control circuit that generates distinct Off voltages for each mode, with the second Off voltage being greater than the first, ensuring efficient switching and noise minimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single Off voltage is used for both transmitting and receiving modes, then the circuit design is simplified, but switching speed and noise resistance are reduced
Solution Approach 1:
The patent applies different Off voltages to different transistor groups based on their functional requirements: a first Off voltage is applied to the first transistor group during transmitting mode, and a second Off voltage is applied to the second transistor group during receiving mode. This localized differentiation optimizes switching performance for each mode without requiring complete redesign of the entire control system.
Solution Approach 2:
The control circuit dynamically switches between different Off voltage levels based on the operational mode. The switch control circuit generates mode-dependent control signals that adjust the Off voltage applied to transistor groups, enabling the system to adapt its electrical characteristics for optimal performance in transmitting versus receiving operations.
2Speed
If higher Off voltage is used to improve switching speed, then switching operation becomes faster, but signal linearity deteriorates
Solution Approach 1:
Different Off voltage levels are applied to different transistor groups based on their specific operational requirements. The first transistor group receives a first Off voltage optimized for transmitting mode linearity, while the second transistor group receives a second Off voltage optimized for receiving mode switching speed, allowing each group to operate at its optimal voltage level.
Solution Approach 2:
The patent changes the voltage parameter dynamically based on operational mode and transistor group. By adjusting the Off voltage level according to the specific mode (transmitting or receiving) and the specific transistor group being controlled, the system optimizes both switching speed and signal linearity without compromise.
3Object-affected harmful factors
If conventional switching control is used, then the circuit design is simple, but noise resistance and signal integrity are reduced
Solution Approach 1:
The control circuit is segmented into multiple control paths, with separate control signals generated for different transistor groups. The switch control circuit produces distinct control voltages for the first and second transistor groups, allowing independent optimization of noise resistance and switching characteristics for each group without increasing overall system complexity significantly.
Solution Approach 2:
The switch control circuit acts as an intermediary that translates operational mode requirements into appropriate control voltages for different transistor groups. This intermediary component coordinates the application of different Off voltages to different transistor groups, improving noise resistance and signal integrity while maintaining manageable circuit complexity.
Data Source
AI summary
An RF switch circuit is provided. The RF switch circuit may include a first switch disposed between a transmitting port and an antenna port and including a plurality of first transistors; a second switch disposed between the antenna port and a receiving port and including a plurality of second transistors; and a switch control circuit configured to generate control voltages to control the first transistors and the second transistors, generate a first Off voltage to turn off at least one first transistor among the plurality of first transistors and the plurality of second transistors in a transmitting mode, and generate a second Off voltage to turn off at least one second transistor among the plurality of first transistors and the plurality of second transistors in a receiving mode, wherein the second Off voltage may be higher than the first Off voltage.