RF Bias Voltage Circuit for Low-Loss Switch Isolation

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Solution Overview

Problem

Existing RF devices face challenges in efficiently generating bias voltages for RF switches, which are crucial for maintaining the conduction state of RF transmission paths, as current solutions often result in high insertion loss during the ON state and inadequate isolation during the OFF state.

Innovation Solution

A voltage generating circuit comprising a rectification circuit and a voltage adjustment circuit that receives a radio frequency signal, generates auxiliary voltages, and adjusts them to provide bias voltages for RF switches, using a combination of voltage dividing components and control signals to optimize the conduction state of RF transmission paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional bias voltage generation methods are used, then the RF switch can operate, but insertion loss during the ON state is high

Engineering Contradiction:
Improveinsertion lossVSAvoidconduction state stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The bias voltage generation circuit dynamically adjusts the bias voltage based on the RF signal power level. When the RF signal power is high, the circuit generates a higher bias voltage to reduce insertion loss. When the RF signal power is low, the circuit generates a lower bias voltage to maintain adequate isolation. This dynamic adjustment resolves the contradiction between minimizing insertion loss and maintaining reliable conduction state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the bias voltage parameter according to the RF signal power level. By varying the bias voltage from a first level (when RF power exceeds first threshold) to a second level (when RF power is below first threshold), the system optimizes insertion loss while maintaining conduction state stability. This parameter change strategy directly addresses the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional bias voltage generation methods are used, then the RF switch can operate, but isolation during the OFF state is inadequate

Engineering Contradiction:
Improveisolation performanceVSAvoidinsertion loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The bias voltage generation circuit dynamically switches between different bias voltage levels based on RF signal power detection. When RF power is low, the circuit provides a second bias voltage level that ensures adequate isolation. When RF power is high, it switches to a first bias voltage level that minimizes insertion loss. This dynamic behavior resolves the contradiction between isolation performance and insertion loss.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention employs feedback by detecting the RF signal power level and using this information to control the bias voltage generation. The detection circuit monitors RF power and feeds this information back to the bias voltage generation circuit, which adjusts the bias voltage accordingly. This feedback mechanism ensures both adequate isolation and minimal insertion loss by adapting to real-time signal conditions.

Inventive Principle:
Principle #23Feedback

3Device complexity

If fixed bias voltage is applied, then circuit design is simple, but performance cannot be optimized for varying RF signal levels

Engineering Contradiction:
Improvecircuit design complexityVSAvoidRF transmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The bias voltage generation circuit performs multiple functions: it detects RF signal power level, generates appropriate bias voltage levels, and controls the RF switch operation. This multi-functional design optimizes RF transmission efficiency across varying signal levels while maintaining reasonable circuit complexity. The single integrated circuit handles what would otherwise require multiple separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The bias voltage generation circuit is self-regulating, automatically adjusting its output based on the detected RF signal power level without external intervention. The circuit uses its own internal detection and control mechanisms to optimize performance, eliminating the need for complex external control circuits and maintaining simplicity while achieving optimization.

Inventive Principle:
Principle #25Self-service

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 effectively reduces insertion loss during the ON state and increases isolation during the OFF state, improving the overall performance of RF switches by dynamically adjusting bias voltages based on the RF signal and system voltage.

Implementation Method 1

The rectification circuit has an input terminal adapted to receive a radio frequency signal, and the rectification circuit is configured to generate at least one auxiliary voltage related to the radio frequency signal

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP3609084B1Radio frequency device and bias voltage generating circuit thereof
Publication Date: 2023.10.04 RICHWAVE TECH CORP
  • EP3609084B1 patent drawingFigure 1~2
  • EP3609084B1 patent drawingFigure 3
  • EP3609084B1 patent drawingFigure 4

AI summary

A radio frequency (RF) device (100) and its voltage generating circuit (110) are provided. The RF device (100) includes the voltage generating circuit (110) and a RF circuit (120). The voltage generating circuit (110) receives a RF signal (RFC) and generates at least one bias voltage (VB) related to the RF signal (RFC). The RF circuit (120) is used to receive the RF signal (RFC). The RF circuit (120) is coupled to the voltage generating circuit (110) to receive the bias voltage (VB). The bias voltage (VB) is used to operate the conduction state of at least one RF transmission path of the RF circuit (120).