RF Amplifier Protection Circuit With Adaptive Signal Path Switching

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Solution Overview

Problem

Existing RF amplifier protection circuits require fixed level clamp components, which increase physical area and production costs, and fail to provide adaptable protection for different gain modes and frequencies.

Innovation Solution

The implementation of switchable RF paths with programmable RF level detectors that selectively couple RF signals to RF amplifiers, allowing for adaptive clamping levels and reduced component usage by switching off or attenuating signals when voltage levels exceed a reference trip voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fixed level clamp circuits are used for protection, then the amplifier is protected from voltage damage, but the physical area and production cost increase

Engineering Contradiction:

Improveamplifier protectionVSAvoidcircuit physical area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The RF signal path components (switches, attenuators, detectors) are designed to serve dual purposes: normal signal processing and protection functions. The same switch used for signal routing is also used to disconnect during overvoltage conditions, eliminating the need for separate protection components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The protection function is extracted from dedicated clamp circuits and integrated into the existing RF signal path components. The detector circuit monitors voltage levels and triggers protection actions through existing switches and attenuators, removing separate protection hardware.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If fixed level clamp circuits are used for protection, then the amplifier is protected from voltage damage, but production cost increases

Engineering Contradiction:

Improveamplifier protectionVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Existing RF components are designed to perform both signal processing and protection functions. The switch matrix used for signal routing also provides protection switching, and the attenuator used for gain control also provides attenuation during overvoltage conditions, reducing component count and manufacturing cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The protection circuit functionality is merged with the RF signal path components. The detector, switch, and attenuator that normally handle signal processing are combined to also perform protection functions, eliminating separate protection circuitry and reducing production costs.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If fixed level clamp circuits are used, then protection is provided at a fixed level, but adaptability to different gain modes and frequencies is lost

Engineering Contradiction:

Improveprotection levelVSAvoidadaptability to gain modes and frequencies

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The protection system transitions from fixed clamp levels to dynamic, programmable protection levels. The detector circuit can be programmed with different threshold values corresponding to different gain modes and frequency operations, allowing the protection level to adapt dynamically to current operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The protection thresholds are made programmable and adjustable based on operating parameters. Different gain modes and frequency settings can program different detection thresholds and attenuation levels, allowing the protection system to adapt to varying operational requirements rather than using fixed clamp levels.

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If programmable RF level detectors are used, then adaptive protection is achieved, but device complexity increases

Engineering Contradiction:

Improveadaptive protection capabilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The programmable detector and switch matrix are designed to serve multiple functions: normal signal routing, gain control, and adaptive protection. The same programmable logic used for signal processing control is also used for protection threshold setting, avoiding duplicate circuitry and minimizing complexity increase.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The protection control functionality is merged with the existing signal processing control logic. The programmable detector, switch controller, and attenuator form an integrated protection system that shares control infrastructure with normal operation, reducing the complexity overhead of adding adaptive protection capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11239803B2Ruggedness protection circuit

Publication Date: 2022.02.01 PSEMI CORP

AI summary

Various methods and circuital arrangements for protection of an RF amplifier are presented. According to one aspect, the RF amplifier is part of switchable RF paths that may include at least one path with one or more attenuators or switches that can be used during normal operation to define different modes of operation of the at least one path. An RF level detector monitors a level of an RF signal during operation of any one of the switchable RF paths and may control the attenuators or switches to provide an attenuation of the RF signal according to a desired level of protection at an input and/or output of the RF amplifier. According to another aspect, the RF level detector may control a switch to force the RF signal through a different switchable RF path.