RF Switch Odd-Even Gate Isolation for Leakage-Delay Tradeoff

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Solution Overview

Problem

Existing radio frequency switch designs with multiple serially connected transistors face challenges in balancing gate leakage current reduction and transmission efficiency, often resulting in excessive signal loss due to increased serial resistors which can lead to transmission delays.

Innovation Solution

The design divides 2N serially connected transistors into odd and even groups, with specific resistor coupling between gate control signals and substrates to reduce leakage currents while maintaining efficient signal transmission, using separate resistor isolation for each group to achieve a trade-off between leakage suppression and transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If multiple transistors are serially connected to reduce gate leakage current, then gate leakage current is reduced, but transmission efficiency deteriorates due to increased signal loss

Engineering Contradiction:
Improvegate leakage currentVSAvoidsignal loss
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent segments the serially connected transistors into two groups: odd-numbered transistors and even-numbered transistors. Each group is controlled by separate control signals (first control signal and second control signal respectively), allowing independent optimization of control strategies for each group to balance leakage reduction and signal transmission efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different control approaches to different parts of the transistor chain. Odd-numbered transistors receive the first control signal while even-numbered transistors receive the second control signal, enabling localized optimization where each group can be tuned for its specific performance requirements regarding leakage and transmission.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If isolation resistors are added to reduce gate leakage current, then gate leakage current is reduced, but transmission delay increases

Engineering Contradiction:
Improvegate leakage currentVSAvoidtransmission delay
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent divides the control path into two separate segments: one for odd-numbered transistors and one for even-numbered transistors. This segmentation allows the control signals to be optimized independently, reducing the cumulative effect of isolation resistors on transmission delay while maintaining leakage current reduction benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies isolation resistors selectively to only the control paths of odd-numbered transistors (or even-numbered, depending on implementation), rather than all transistors. This partial application reduces the total resistance in the control signal path, thereby reducing transmission delay while still achieving sufficient leakage current reduction for the critical transistors.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2945287B1Switch, antenna tuner, and radio frequency apparatus
Publication Date: 2018.02.28 HUAWEI TECH CO LTD
  • EP2945287B1 patent drawingFigure 1~2A
  • EP2945287B1 patent drawingFigure 2B~3
  • EP2945287B1 patent drawingFigure 4~5

AI summary

A switch, an antenna tuner, and a radio frequency apparatus are provided. The switch includes: 2N successively serially connected transistors. In the 2N successively serially connected transistors, control ends of any two transistors with closest odd sequence numbers are coupled to each other through a first resistor, and control ends of any two transistors with closest even sequence numbers are coupled to each other through a second resistor; a control end of an n-th transistor is coupled to a first control signal in a switch control signal, and a control end of an (n+1)-th transistor is coupled to the first control signal, where n is an integer that is greater than or equal to 1 and is less than or equal to 2N-1, N is an integer greater than or equal to 2, and the first control signal is used to control turn-on or turn-off of the switch.