Single-Chip RF Front End With LNA Protection From PA Output

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Solution Overview

Problem

Conventional wireless systems face challenges with separate low-noise amplifiers (LNAs) and power amplifiers on different chips, leading to increased chip count, complexity, and larger circuit board layouts due to adverse power level interactions.

Innovation Solution

A single transceiver chip with a power amplifier capable of operating in both low and high power modes, and a low-noise amplifier tolerant to power amplifier outputs, allowing for integrated design without damage, along with impedance matching and robust components to handle higher power levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LNAs and power amplifiers are placed on separate chips, then the LNA is protected from damage by high power amplifier outputs, but the chip count increases and system complexity increases

Engineering Contradiction:

ImproveLNA protection from damageVSAvoidchip count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the LNA and power amplifier onto a single integrated circuit chip, eliminating the need for separate chips while protecting the LNA from damage by high power amplifier outputs through careful design of the shared chip architecture

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single chip is designed to perform multiple functions - both low-noise amplification of received signals and high-power amplification of transmitted signals - making the chip universal and eliminating the need for separate dedicated chips for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If LNAs and power amplifiers are placed on separate chips, then the LNA is protected from damage by high power amplifier outputs, but the printed circuit board layout area increases

Engineering Contradiction:

ImproveLNA protection from damageVSAvoidprinted circuit board layout area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

By merging the LNA and power amplifier into a single integrated chip, the patent dramatically reduces the space required on the printed circuit board, as the entire dual-function amplifier system occupies the area of one chip rather than requiring separate mounting areas for two chips plus interconnecting traces

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If a single transceiver chip is used with both LNA and power amplifier, then system complexity is reduced and chip count is minimized, but the LNA may be damaged by high power amplifier outputs

Engineering Contradiction:

Improvesystem complexityVSAvoidLNA protection from damage

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the chip into distinct transmit and receive signal paths with separate processing chains, allowing the LNA to process received signals while being isolated from the high-power transmit signals, thus preventing damage while maintaining integration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces switching mechanisms and isolation circuits as intermediaries between the LNA and power amplifier, controlling signal flow to prevent high-power transmit signals from reaching and damaging the LNA while allowing both components to coexist on the same chip

Inventive Principle:

Principle #24Intermediary (Mediator)

4Power

If the power amplifier operates in high power mode, then transmit power is increased, but the LNA input transistors may exceed breakdown voltage

Engineering Contradiction:

Improvetransmit powerVSAvoidbreakdown voltage exceeded

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent segments the amplifier system into transmit and receive modes with separate signal paths, ensuring that when the power amplifier operates in high-power transmit mode, the LNA is isolated from these high-voltage signals through switching mechanisms

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic switching between transmit and receive modes, with the switch controlling signal flow to direct high-power transmit signals away from the LNA during transmit periods and allow received signals to pass through the LNA during receive periods

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS8600315B2Method and system for a configurable front end

Publication Date: 2013.12.03 NXP USA INC

AI summary

Methods and systems for a configurable front end are disclosed. Aspects of one method may include a transceiver on a single chip that may comprise a power amplifier (PA) and a low noise amplifier (LNA). The PA may amplify signals to be transmitted over a range of output transmit power. An upper limit for a power range may of substantially 12 dBm. The LNA may be tolerant to PA signals by, for example, being configured to follow signal voltages generated from an output of the power amplifier. For example, each input transistor of the LNA may be isolated from other transistors in the LNA. Accordingly, the input transistors may float since they may not be tied to a voltage level via other transistors. This may allow the input transistors to avoid damage. The transceiver may also be configured for differential RF input, differential RF output, single-ended RF input, and/or single-ended RF output. In some configurations, the transceiver may also support use of a power amplifier external to the transceiver to amplify RF signals communicated by the transceiver.