RF Semiconductor Switch Off-Potential Control for Low Harmonic Distortion
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Solution Overview
Problem
Semiconductor switches in radio frequency circuits face challenges in maintaining optimal Off-potential Voff levels to minimize third-order harmonic distortion, which affects the maximum allowable input power and distortion levels, especially in GSM and UMTS standards, where precise control of potential levels is crucial for efficient signal switching.
Innovation Solution
A semiconductor switch configuration that includes a power supply with a first potential generator for generating a negative first potential and a second potential generator for stepping down the power supply potential, along with a driver and a first potential controller using a divider and amplifier to stabilize the first potential, ensuring it approaches a reference potential, thereby optimizing the Off-potential Voff for minimal harmonic distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional MOSFET switch is used in RF circuits, then the device structure is simple, but the third-order harmonic distortion increases and the maximum allowable input power is limited
Solution Approach 1:
The patent applies dynamics by making the Off-potential Voff adjustable rather than fixed. The control circuit dynamically adjusts Voff based on the applied RF signal characteristics to optimize the balance between distortion and input power handling. This is achieved through feedback mechanisms that modify the gate-source voltage in real-time during operation.
Solution Approach 2:
The patent changes the electrical parameters of the MOSFET by controlling the Off-potential Voff to specific optimized values. By adjusting Voff, the patent modifies the electric field distribution in the channel, which changes the device's nonlinear characteristics and reduces third-order harmonic distortion while maintaining acceptable input power levels.
2Object-generated harmful factors
If the Off-potential Voff is adjusted to minimize third-order harmonic distortion, then the distortion level decreases, but the maximum allowable input power is reduced
Solution Approach 1:
The patent resolves this contradiction by making Voff dynamically adjustable rather than statically optimized. The control circuit monitors RF signal characteristics and adjusts Voff in real-time, allowing the system to operate at optimal distortion levels for varying input power conditions. This dynamic adaptation enables the system to maintain low distortion across a broader range of input power levels.
Solution Approach 2:
The patent implements feedback control where the actual Voff and RF signal characteristics are monitored, and the control circuit adjusts Voff based on this feedback to optimize the trade-off between distortion and input power. The feedback mechanism allows the system to automatically adapt to changing conditions and maintain optimal performance.
3Object-generated harmful factors
If precise control of potential levels is implemented, then the harmonic distortion is minimized, but the device complexity increases
Solution Approach 1:
The patent introduces a control circuit as an intermediary between the RF signal input and the MOSFET gate. This intermediary circuit manages the complexity of precise potential control by implementing the adjustment logic separately, allowing the main RF switching function to remain simple while adding intelligence only where needed for distortion optimization.
Solution Approach 2:
The control circuit is designed to automatically adjust Voff based on monitored signal characteristics without requiring external intervention. The system serves itself by using its own output signals as input for the control algorithm, reducing the need for external complex control systems while achieving precise potential management.
Data Source
AI summary
According to one embodiment, a semiconductor switch includes a power supply, a driver, a switch section, and a first potential controller. The power supply includes a first potential generator and a second potential generator. The first potential generator is configured to generate a negative first potential. The second potential generator is configured to generate a positive second potential that a power supply potential is stepped down. The driver is supplied with the first potential and a third potential and configured to output at least one of the first potential and the third potential based on a terminal switching signal. The switch section is configured to connect a common terminal to any one of a plurality of radio frequency terminals according to an output of the driver. The first potential controller includes a divider and an amplifier.