RF Switch Compensation Network for Leakage Bias Stability

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Solution Overview

Problem

High voltage radio frequency switches face parasitic leakage currents that shift the designed bias voltage, leading to performance loss and signal distortion at high operating voltages.

Innovation Solution

Incorporation of leakage current compensation circuits, utilizing non-linear elements like diodes, to bypass leakage currents away from bias resistors and back into the switch, maintaining desired bias voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If transistors are stacked in series configuration to handle high voltage, then the radio frequency switch can operate at high voltage levels, but parasitic leakage currents flow in and out of the transistors altering the designed bias voltage values

Engineering Contradiction:
Improvevoltage handling capabilityVSAvoidbias voltage stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

A compensation network is introduced as an intermediary component between the transistors in the series stack. This network includes compensation transistors and bias circuits that actively counteract the parasitic leakage currents, serving as a mediator to maintain bias voltage stability while allowing high voltage operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The compensation network employs feedback mechanisms where bias circuits continuously monitor and adjust the bias voltages applied to the compensation transistors. This feedback loop ensures that the compensation current dynamically counteracts the parasitic leakage currents, maintaining stable operating points despite high voltage conditions.

Inventive Principle:
Principle #23Feedback

2Reliability

If compensation networks are added to mitigate leakage currents, then bias voltage stability is improved, but device complexity increases

Engineering Contradiction:
Improvebias voltage stabilityVSAvoidcircuit structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The compensation network is segmented into modular units, with each compensation transistor paired with its own bias circuit. This segmentation allows the complex compensation function to be divided into manageable, independent modules that can be systematically integrated into the series transistor stack.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compensation mechanism operates by dynamically changing the bias voltage parameters applied to the compensation transistors. By adjusting these voltage parameters in response to parasitic leakage currents, the system achieves bias voltage stabilization without requiring fundamentally different circuit topologies.

Inventive Principle:
Principle #35Parameter changes

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

The solution effectively mitigates the shift in operating points of transistors, reducing signal distortion and maintaining performance at high voltages, even with significant leakage currents.

Implementation Method 1

a first compensation network coupled between the body terminal of the first transistor and the drain terminal of the second transistor, wherein the first compensation network is configured to establish a path for current flowing between the body terminal of the first transistor and the drain terminal of the second transistor in a first direction and to block current flowing therebetween in a second direction opposite to the first direction

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP3720001B1Radio frequency switch device with compensation and compensation method
Publication Date: 2021.11.10 INFINEON TECHNOLOGIES AG
  • EP3720001B1 patent drawingFigure 1
  • EP3720001B1 patent drawingFigure 2A
  • EP3720001B1 patent drawingFigure 2B

AI summary

A radio frequency switch includes a first transistor and a second transistor coupled together to establish a switchable radio frequency path, and a first compensation network coupled between the body terminal of the first transistor and the drain terminal of the second transistor, wherein the first compensation network establishes a path for current flowing between the body terminal of the first transistor and the drain terminal of the second transistor in a first direction and blocks current flowing in a second direction opposite to the first direction.