RF Switch Topology for Low Leakage and Low Insertion Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High power radio frequency switches face challenges in achieving low leakage current and low insertion loss, with stacked transistors increasing insertion loss in low power modes while limiting bandwidth.
Innovation Solution
Designing an RF switch with all transistors in an on state during high power mode and all in an off state during low power mode, reducing the number of transistors in each state to minimize insertion loss without compromising bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stacked transistors are used to prevent leakage current and transistor breakdown, then reliability is improved, but insertion loss increases in low power receive mode
Solution Approach 1:
The patent implements dynamic control of transistor states based on operating mode. In high power transmit mode, all transistors are turned on to handle high voltage and prevent breakdown. In low power receive mode, all transistors are turned off to minimize insertion loss. This dynamic reconfiguration allows the system to adapt transistor states to operational requirements, resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The patent changes the operational state parameter of the transistors from static to dynamic. By controlling the gate voltage to switch all transistors between on and off states based on power mode, the system optimizes both leakage current prevention and insertion loss. The parameter change enables the same transistor stack to serve dual purposes: high voltage blocking in transmit mode and low loss path in receive mode.
2Loss of energy
If channel width of transistors is increased to reduce insertion loss, then insertion loss is reduced, but bandwidth is limited
Solution Approach 1:
The patent uses dynamic transistor state control to achieve low insertion loss without requiring increased channel width. By turning all transistors off in receive mode, the signal path bypasses the transistor channels entirely, eliminating channel resistance effects on bandwidth. This dynamic approach decouples insertion loss from channel width constraints, allowing optimal bandwidth performance.
3Power
If all transistors are in on state during high power mode, then power handling capability is improved, but leakage current increases
Solution Approach 1:
The patent implements mode-dependent transistor control where all transistors are turned on during high power transmit mode to handle high voltage and power. During low power receive mode, all transistors are turned off to eliminate leakage current paths. This dynamic switching resolves the contradiction by ensuring leakage current is minimized when power handling is not required, while maintaining full power handling capability when needed.
Data Source
AI summary
High power radio frequency (RF) switches with low leakage current and low insertion loss are provided. In one embodiment, an RF switch includes a plurality of transistors and is configured to selectively connect one of a transmit path or a receive path to an antenna. All of the transistors are configured to be in an on state when the RF switch operates in a high power mode and all of the transistors are configured to be in an off state when the RF switch operates in a low power mode.