Configurable RF Receiver Front End for Filter-LNA Reordering
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Solution Overview
Problem
Existing wireless devices require separate off-chip filters for transmit and receive paths, consuming circuit board area and increasing material costs, and lack flexibility in adapting to different operating environments.
Innovation Solution
A configurable receiver front end module that uses switch circuitry to dynamically reconfigure the relative order of an RF filter and LNA based on signal metric information, allowing a single off-chip filter to be shared between transmit and receive paths and optimizing operation for different environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate off-chip filters are used for transmit and receive paths, then filtering performance is ensured, but circuit board area increases and material costs increase
Solution Approach 1:
The patent merges the transmit and receive filter paths into a single shared off-chip filter. Switching circuitry dynamically connects the filter to either the transmit path or receive path based on operational mode, eliminating the need for separate filters and reducing circuit board area while maintaining filtering performance in both paths
Solution Approach 2:
The single off-chip filter is designed to serve multiple functions by being shared between transmit and receive paths. The filter maintains its filtering performance for both transmit signals and receive signals, achieving universality while reducing component count and material costs
2Device complexity
If radio solutions are designed to statically operate in a single environment, then design simplicity is maintained, but flexibility and adaptability to different environments are reduced
Solution Approach 1:
The patent implements dynamic reconfiguration of the RF front end circuit by using switching circuitry that can change the relative order of the LNA and RF filter based on signal metric information. This dynamic switching between different operational modes (first mode with LNA before filter, second mode with filter before LNA) enables the system to adapt to varying RF environments while maintaining a relatively simple overall design architecture
3Adaptability or versatility
If the RF front end circuit is reconfigured dynamically based on signal metrics, then flexibility and environmental adaptation are improved, but device complexity increases
Solution Approach 1:
The patent employs feedback mechanisms where signal metric information is continuously monitored and used to control the switching circuitry. The system measures signal characteristics and automatically adjusts the filter-LNA ordering based on these measurements, enabling adaptive environmental response through a controlled feedback loop that manages complexity
Solution Approach 2:
The RF front end circuit performs self-configuration by automatically adjusting its own topology based on internally measured signal metrics. The system monitors its own operational conditions and autonomously reconfigures the component ordering without external intervention, reducing the burden on external control systems while achieving adaptability
Data Source
AI summary
In one aspect, a method comprises: comparing, in a comparator, a signal level of a receive radio frequency (RF) signal to a first threshold, the receive RF signal obtained from a controllable location in an RF front end circuit; and in response to the signal level of the receive RF signal exceeding the first threshold, causing the RF front end circuit to be reconfigured from a first mode in which an input to a low noise amplifier (LNA) is coupled an antenna to a second mode in which the input to the LNA is coupled to an RF filter.