Transformer-Coupled Radio Front End for Receiver Voltage Isolation
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Solution Overview
Problem
Bi-directional radio communication systems face reliability issues due to high voltage stress on receiver transistor devices caused by transmitter signals, leading to potential device breakdown and performance degradation, especially when using off-chip T/R switches that introduce resistance and parasitic capacitance.
Innovation Solution
A transformer with multiple windings is used to provide shared access to the antenna between the transmitter and receiver, utilizing magnetic coupling to limit the voltage of signals received by the receiver to within a predetermined threshold, thereby reducing high-voltage stress on transistor devices, and incorporating a switch to prevent leakage current during transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed electrical connection is used between transmitter and antenna, then the transmitter can transmit signals to the antenna, but the receiver is exposed to high voltage stress from transmitter signals which can lead to device breakdown
Solution Approach 1:
A transformer is introduced as an intermediary component between the transmitter and receiver circuits. The transformer provides galvanic isolation while allowing magnetic coupling, so that the receiver is protected from high voltage stress from the transmitter while still being able to receive signals from the antenna. The transformer acts as a mediator that transfers energy without direct electrical connection.
2Reliability
If a T/R switch is used to isolate the receiver from transmitter signals, then the receiver is protected from voltage stress, but the switch introduces resistance and parasitic capacitance that degrades performance
Solution Approach 1:
The patent replaces the mechanical/electronic T/R switch with a transformer-based isolation approach. Instead of using switches that introduce resistance and parasitic capacitance, the transformer provides isolation through magnetic coupling, eliminating the harmful electrical characteristics of switches while maintaining receiver protection.
3Speed
If the transmitter transmits signals with large voltage swing to cover signal attenuation, then the transmitted signal can propagate over distance, but the high voltage level causes high voltage stress to the receiver's transistor devices
Solution Approach 1:
The transformer serves as an intermediary that allows the transmitter to operate at high voltage levels for long-distance signal propagation while protecting the receiver from these high voltages. The magnetic coupling transfers the signal energy without exposing the receiver to the full voltage swing of the transmitted signal.
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 improves the reliability of the communication system by reducing voltage stress on receiver devices and minimizing insertion loss, enhancing operational bandwidth and overall system performance.
Implementation Method 1
The first transmitter circuit is configured to transmit a first signal to the antenna via magnetic coupling between the first winding and the third winding
Implementation Method 2
a turn ratio between the first winding and the second winding can be configured to limit a voltage of the second signal to be within a pre-determined threshold
Data Source
AI summary
Apparatus and methods for performing wireless communications are provided. In some embodiments, an apparatus includes a transformer including a first winding, a second winding, and a third winding. The apparatus also includes a first transmitter circuit coupled with the first winding, and a second circuit coupled with the second winding. The third winding is coupled with an antenna. The first transmitter circuit is configured to transmit a first signal to the antenna via magnetic coupling between the first winding and the third winding. The second circuit is configured to tolerate without damage a second signal from the first transmitter circuit, wherein the second signal is generated from the first signal via magnetic coupling between the first winding and the second winding. A turn ratio between the first winding and the second winding can be configured to limit a voltage of the second signal to be within a pre-determined threshold.