RF Switch Transistor Stacking With Bulk Bias Equalization
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Solution Overview
Problem
Existing RF switching circuits face challenges in achieving high average power withstanding capability and low insertion loss, particularly due to uneven voltage distribution and nonlinear phenomena in stacked transistor chains.
Innovation Solution
The RF switching circuit employs a series connection of switch transistor units, each comprising a first and second transistor, bias resistors, and a path resistor, with specific connections to gate and bulk bias voltages, effectively addressing voltage distribution and nonlinearity issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stacked chain of switch transistors is used to increase power withstanding capability, then the voltage withstanding capability is improved, but the voltage swings become unevenly distributed and nonlinearity increases
Solution Approach 1:
A bulk voltage adjustment circuit is introduced as an intermediary component between the stacked transistors. This circuit includes a bulk adjustment transistor connected to the bulk of each switch transistor through separate bulk adjustment resistor paths, allowing independent control and equalization of bulk voltages across all transistors in the stack, thereby achieving uniform voltage swing distribution
Solution Approach 2:
Each switch transistor in the stacked chain is provided with separate bulk adjustment resistor paths connected to the bulk adjustment transistor, enabling localized control of bulk voltage for each transistor. This local quality adjustment ensures that each transistor operates with optimal and uniform voltage characteristics
2Strength
If more switch transistors are stacked to increase power withstanding capability, then the voltage tolerance is improved, but the insertion loss increases and linearity deteriorates
Solution Approach 1:
The bulk adjustment transistor serves as a mediator that equalizes the bulk voltages across all stacked transistors, ensuring uniform operating conditions. This mediation prevents excessive voltage drops and reduces insertion loss while maintaining the high power withstanding capability of the stacked configuration
Solution Approach 2:
The invention changes the bulk voltage parameter for each transistor in the stack by introducing adjustable bulk resistor paths. By controlling the bulk voltage parameter uniformly across all transistors, the system achieves better linearity and reduced insertion loss while maintaining high power tolerance
Data Source
AI summary
A radio frequency switching circuit which has high tolerance power, a chip and an electronic device thereof. The radio frequency switching circuit is composed of multiple stages of switching transistor units connected in series. According to the radio frequency switching circuit, the phenomenon of uneven distribution of a voltage swing in stages of a switching transistor stacking chain is improved, so that the problem of nonlinearity of the radio frequency switching circuit is improved, the insertion loss is reduced, and the average tolerance power is significantly improved.