RF Switch Stack Sizing Using Gate and Body Off-Voltage Limits
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Solution Overview
Problem
The existing RF switch designs face challenges in determining the optimal stacking number of FETs, leading to breakdown or leakage issues due to inadequate control of gate and body voltages, which affects P1dB and power handling capabilities.
Innovation Solution
An apparatus and method that calculates the optimum stacking number of RF switches by determining gate-off and body-off voltages, using a processor to calculate terminal voltages based on stored peak and limiting voltages, and applying these voltages to control transistors in series to enter an OFF state, ensuring the voltages satisfy specific conditions to prevent breakdown and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of stacked FETs is increased to prevent breakdown and leakage, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting gate-off voltage and body-off voltage based on the actual stacking number of FETs. The processor calculates optimal voltage values using stored peak voltage data and limiting voltage characteristics, then applies these calculated voltages to prevent breakdown and leakage. This resolves the contradiction by optimizing electrical parameters rather than simply increasing the number of stacked FETs, thereby maintaining reliability while potentially reducing device complexity.
2Ease of manufacture
If the stacking number is determined based only on breakdown voltage, then ease of manufacture is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent implements feedback by using a processor to calculate the optimum stacking number based on multiple parameters including peak voltage, gate limiting voltage, drain-source limiting voltage, and body limiting voltage. The system stores these parameters in memory and uses them to dynamically determine the optimal stacking configuration. This feedback mechanism ensures manufacturing precision by considering all critical voltage parameters rather than relying solely on breakdown voltage, while still maintaining ease of manufacture through automated calculation.
3Power
If more stacks are used to handle higher signal intensity, then power handling capability is improved, but insertion loss increases
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the gate-off voltage and body-off voltage based on the determined optimum stacking number and actual operating conditions. The processor calculates optimal voltage values that adapt to different signal intensities and stacking configurations. This dynamic adjustment allows the RF switch to maintain optimal performance across varying power levels, improving power handling capability while minimizing insertion loss by preventing both breakdown and leakage conditions.
Data Source
AI summary
An apparatus for determining an optimum stacking number of an RF switch, in which a gate-off voltage and a body-off voltage are used to control transistors stacked in series to enter an OFF state. The apparatus includes a memory configured to store a peak voltage of a high-frequency signal in a corresponding band, and a gate limiting voltage, a drain-source limiting voltage, and a body limiting voltage in a corresponding process for each of the transistors, and a processor configured to calculate a gate terminal voltage, a drain-source voltage, and a body terminal voltage using the peak voltage, the gate limiting voltage, the drain-source limiting voltage, and the body limiting voltage and to determine an optimum stacking number based on the gate terminal voltage, the gate limiting voltage, the drain-source voltage, the drain-source limiting voltage, the body terminal voltage, and the body limiting voltage.