RF Switch Control That Disables Charge Pump in Receive Mode

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Solution Overview

Problem

Radio frequency switches using silicon-on-insulator technology generate spurious signals during the receive mode, degrading sensitivity due to interference from charge pump circuits.

Innovation Solution

A radio frequency switch design that controls the switching circuit with a first state from a charge pump circuit in transmit mode and a second state from a reference voltage in receive mode, disabling the charge pump circuit during receive mode to prevent spurious signal generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charge pump circuit is used to control the switching circuit in transmit mode, then the switching circuit can be properly controlled, but spurious signals are generated during receive mode that degrade sensitivity

Engineering Contradiction:

Improveswitching control reliabilityVSAvoidspurious signal interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the charge pump circuit's operational state changeable - it is enabled during transmit mode to provide proper switching control, and disabled during receive mode to eliminate spurious signal generation. This dynamic switching of the charge pump circuit's operational state resolves the contradiction between needing reliable switching control and avoiding harmful spurious signals.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the charge pump circuit remains active during receive mode, then switching control is maintained, but power consumption increases and spurious signals are generated

Engineering Contradiction:

Improveswitching control continuityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by enabling the charge pump circuit only during transmit mode operations and disabling it during receive mode operations. This periodic activation based on operational mode ensures that power is consumed only when the charge pump is needed for switching control, rather than continuously, thus reducing overall power consumption while maintaining reliability when needed.

Inventive Principle:

Principle #19Periodic action

3Object-affected harmful factors

If frequency filters are added to eliminate spurious signals, then sensitivity is improved, but device complexity increases

Engineering Contradiction:

Improvespurious signal rejectionVSAvoidcircuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies the taking out principle by removing the charge pump circuit from the active configuration during receive mode, rather than trying to filter its spurious outputs. By extracting/disabling the problematic charge pump circuit when not needed, spurious signal generation is eliminated at the source, avoiding the need to add complex frequency filtering circuits to the receive path.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20250337406A1Radio frequency switch and method

Publication Date: 2025.10.30 STMICROELECTRONICS INT NV

AI summary

The present description concerns a radio frequency switch comprising a control circuit configured to, in a radio frequency signal transmit mode, control a switching circuit with a first state originating from an output of a charge pump circuit, and, in a radio frequency signal receive mode, disable the charge pump circuit and control the switching circuit with a second state originating from a reference voltage.