Switchable Charge Pump Network for RF Transmit-Receive Systems
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Solution Overview
Problem
Broadband RF systems face challenges in protecting the receive path from high incident signal levels while maintaining low loss and handling high power levels, particularly in shared antenna systems.
Innovation Solution
A switchable charge pump network is introduced, comprising a switching element and a charge pump circuit that can be activated or deactivated based on operating mode, forming a single-pole N-throw switched network to enable safe operation by isolating the receive path from high incident signals with minimal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 5-port circulator is used to protect the receive path from high incident signal levels, then the receive path is protected, but the system is limited to narrowband and medium-bandwidth applications
Solution Approach 1:
The patent implements dynamic switching between transmit and receive modes using electronically controllable switches (RF switches or FETs) that can rapidly transition between states. This dynamic switching mechanism enables broadband operation by allowing the system to adapt to different frequency ranges and operational requirements, overcoming the narrowband limitation of fixed circulator designs.
Solution Approach 2:
The invention changes the operational parameters of the switching elements by applying different bias voltages or control signals to transition between transmit and receive modes. By varying the electrical parameters (voltage, current, resistance) of the switching components, the system achieves broadband functionality while maintaining receive path protection through controlled isolation during transmit operations.
2Power
If high signal levels are transmitted to the antenna, then transmit power is delivered, but the receive path is exposed to high incident signal levels that can cause damage
Solution Approach 1:
The patent introduces switching elements (RF switches or FETs) as intermediary components between the transmit amplifier and the antenna/receive path. These intermediaries act as controllable isolation mechanisms that can block high incident signal levels from reaching the receive path while allowing transmit power to reach the antenna during transmit mode, thus protecting the receive path without sacrificing transmit power delivery.
Solution Approach 2:
The system performs preliminary switching actions to establish the appropriate signal path configuration before high power transmission occurs. By pre-positioning the switches in the correct state (transmit mode) before applying high power, the receive path is already isolated and protected from impending high incident signal levels, preventing damage before it can occur.
3Reliability
If the receive path is isolated from the antenna during transmit mode, then protection is provided, but signal loss increases in the transmit path
Solution Approach 1:
The patent implements local quality optimization by designing the switching elements to have low insertion loss in the transmit path while providing high isolation in the receive path. The switches are positioned and configured to minimize their impact on transmit signal strength (maintaining low loss) while effectively blocking signals to the receive path (providing high isolation), thus achieving both protection and low loss through localized performance optimization.
Data Source
AI summary
A switchable charge pump (SCP) combines a switching element and a charge pump. An SCP can be utilized within an RF circuit to allow the charge pump to be activated or deactivated in the circuit depending on incident RF power level. Multiple SCPs can be utilized to provide a generalized a single-pole N-throw (SPNT) system architecture. In one example, an RF transmit-receive (T/R) system utilizes SCPs to operate in one of three modes: transmit mode, receive mode, or self-selecting terminate mode.