Antenna Switch Booster Circuit Reducing Insertion Loss
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Solution Overview
Problem
The existing booster circuit in antenna switches for mobile communication devices experiences a loss due to passing through resistors, leading to a decrease in insertion loss, which is critical for switch characteristics, while trying to reduce harmonic distortion.
Innovation Solution
A semiconductor integrated circuit device with a booster circuit that includes a loss improving resistor to reduce voltage attenuation of the transmission signal, coupled between the second terminal and the boost terminal, and a configuration of capacitive elements and diodes to generate a boost voltage higher than the control signal for the switching transistor circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a booster circuit with diodes and capacitors is used to generate boost voltage, then harmonic distortion is reduced, but insertion loss increases due to voltage attenuation through resistors
Solution Approach 1:
A loss improving resistor is introduced as an intermediary component between the second terminal and the boost terminal. This resistor compensates for the voltage attenuation caused by the existing resistors in the booster circuit path, thereby reducing the net insertion loss while maintaining the boost voltage generation function for harmonic distortion reduction
Solution Approach 2:
The invention changes the electrical parameter (voltage attenuation) by adding a specifically designed loss improving resistor. This resistor's value is optimized to counterbalance the voltage loss in the signal path, transforming the overall voltage attenuation parameter from harmful to beneficial by ensuring sufficient boost voltage reaches the switching transistor gate
2Object-generated harmful factors
If multi-stage connection of FETs is used, then RF voltage per stage is reduced and harmonic distortion is reduced, but the limitation prevents further distortion reduction
Solution Approach 1:
The invention changes the voltage parameter by introducing a booster circuit that generates a boost voltage higher than the control signal voltage. This voltage boosting allows the switching transistor to achieve better off-state isolation without requiring additional multi-stage FET connections, thus reducing harmonic distortion while avoiding increased circuit complexity
Solution Approach 2:
The booster circuit replicates and enhances the control signal voltage to create a boost voltage that is applied to the gate of the switching transistor. This copied and enhanced voltage signal achieves the same distortion reduction effect as multi-stage connections but through a different mechanism that doesn't increase structural complexity
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
Significantly improves insertion loss and reduces harmonic distortion in antenna switches by minimizing voltage attenuation and maintaining sufficient boost voltage.
Implementation Method 1
a voltage is generated in a capacitance 402 by rectification of two diodes 411, 412
Data Source
AI summary
Upon application of an on-state voltage to a control terminal, an antenna switch provided between an antenna terminal and a transmission terminal is turned on, and a transmission signal of a PCS/DCS system passes from the transmission terminal through the antenna terminal. At this time, a booster circuit, to which a part of the transmission signal is supplied, generates at an output terminal a boost voltage higher than a control voltage output from a controller due to the rectification of diodes, and applies the same to the gate of a transistor circuit of the antenna switch. Since in the booster circuit a resistor is coupled to the output terminal, the passage through resistors of an input transmission power in an RF signal path is only the passage through one resistor, thus reducing the attenuation of the transmission signal and providing an excellent insertion loss characteristic.