PIN Diode Bias Circuit Using RF Power for Signal Isolation

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Solution Overview

Problem

Existing PIN diode-based RF switching circuits require external high-voltage power supplies, which increase installation costs and occupy additional input pins, especially in remote infrastructure like base stations, and are inefficient due to the use of high-voltage MOS circuitry.

Innovation Solution

A circuit assembly generates a DC voltage by rectifying and smoothing a radio-frequency input signal to reverse-bias a PIN diode, eliminating the need for an external power supply by leveraging power from within the RF system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external high-voltage power supplies are used to reverse-bias PIN diodes in RF switching circuits, then reliable signal isolation is achieved, but installation costs increase and additional input pins are occupied

Engineering Contradiction:

Improvesignal isolationVSAvoidpower supply requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The circuit uses the RF input signal itself to generate the reverse bias voltage through rectification and smoothing circuits, eliminating the need for external power supplies. The RF signal's own energy is harvested to create the necessary bias condition for diode isolation.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The high-voltage RF input signal, which could potentially cause damage or require complex protection circuitry, is converted into a useful resource by rectifying it to generate the reverse bias voltage needed for safe operation and signal isolation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If external high-voltage power supplies are used to reverse-bias PIN diodes, then effective RF signal isolation is ensured, but installation costs and pin occupancy increase

Engineering Contradiction:

ImproveRF signal isolationVSAvoidinstallation cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The circuit is self-powered by the RF input signal, eliminating the need for external power supply connections and reducing installation complexity and cost, particularly in remote infrastructure locations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The RF input signal serves dual purposes: it is both the signal to be processed and the power source for generating the reverse bias voltage, reducing the number of external connections required.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If high-voltage MOS circuitry is used for diode control, then switching functionality is achieved, but system efficiency decreases

Engineering Contradiction:

Improveswitching functionalityVSAvoidsystem efficiency

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces high-voltage MOS circuitry with a passive rectifying circuit consisting of diodes and capacitors, eliminating the need for complex active switching devices and reducing energy losses associated with MOS transistor operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The solution uses simple, low-cost passive components (diodes and capacitors) instead of expensive and energy-intensive high-voltage MOS circuitry, achieving the same switching function with minimal energy loss.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 approach reduces installation costs and pin occupancy by generating a bias voltage internally, ensuring effective isolation of RF signals without the need for external power supplies, particularly beneficial in high-power applications like 5G communications.

Implementation Method 1

a rectifying circuit configured to receive the radio-frequency input voltage from the input node and generate a rectified voltage

Methodology Applied

Scientific EffectRectification: Diode

Implementation Method 2

a smoothing circuit configured to receive the rectified signal from the rectifying circuit and generate a DC voltage

Methodology Applied

Scientific EffectSmoothing: Capacitance

Data Source

PatentUS12375082B2Devices and methods related to diode switch control

Publication Date: 2025.07.29 SKYWORKS SOLUTIONS INC

AI summary

Embodiments of the invention relate to a circuit assembly for biasing a PIN diode, wherein a DC biasing voltage is obtained by extracting power from a radio-frequency transmission path. The circuit assembly comprises a PIN diode, an input node configured to receive a radio-frequency input voltage, a rectifying circuit configured to receive the radio-frequency input voltage from the input node and generate a rectified voltage, and a smoothing circuit configured to receive the rectified voltage from the rectifying circuit and generate a DC voltage. The output of the smoothing circuit forms the input to the PIN diode to reverse-bias the diode. Related methods, radio-frequency switching circuits and radio-frequency modules are also provided.