Parallel Cascode Amplifier Circuit for RF Distortion Suppression
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Solution Overview
Problem
Existing amplification circuits in mobile devices experience distortion when input with large radio-frequency signals due to low power supply voltage sharing between cascode-connected transistors, leading to increased error rates and reduced communication speed.
Innovation Solution
An amplification circuit design with a first amplifier cascode-connected to a second amplifier, where the second amplifier is connected in parallel, allowing independent power supply to each transistor, thereby preventing voltage division and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If power supply voltage is shared between cascode-connected first and second transistor circuits, then device complexity is reduced, but distortion occurs when large radio-frequency signals are input due to low driving voltage
Solution Approach 1:
The power supply configuration is segmented into two independent power supply circuits: a first power supply circuit providing voltage to the cascode-connected transistor circuit, and a second power supply circuit providing voltage to the parallel-connected transistor circuit. This segmentation allows each circuit to operate with sufficient driving voltage independently, preventing distortion while maintaining manageable device complexity through modular power supply architecture.
2Power
If cascode connection is used between transistors, then gain is improved, but power supply voltage is divided leading to low driving voltage and distortion
Solution Approach 1:
The amplification function is segmented into two independent transistor circuits with separate power supplies. The cascode-connected first transistor circuit provides gain optimization, while the parallel-connected second transistor circuit provides alternative amplification path with sufficient driving voltage from its dedicated power supply, ensuring neither circuit suffers from voltage division.
Solution Approach 2:
The power supply voltage parameters are changed from a single shared voltage to two different voltages: a first power supply voltage for the cascode circuit and a second power supply voltage for the parallel circuit. This parameter change allows independent optimization of each circuit's operating conditions, maintaining high gain while avoiding voltage division-induced distortion.
3Ease of manufacture
If single power supply is used for all transistors, then ease of manufacture is improved, but distortion occurs in high-speed communication scenarios
Solution Approach 1:
The power supply system is segmented into two independent circuits that can be manufactured and tested separately before integration. The first power supply circuit serves the cascode transistor circuit while the second power supply circuit serves the parallel transistor circuit, maintaining manufacturing simplicity through modular design while ensuring communication performance through independent voltage control.
Data Source
AI summary
An amplification circuit includes a first amplifier provided between an input terminal and an output terminal and a second amplifier connected in parallel with the first amplifier between the input terminal and the output terminal. The first amplifier includes a transistor and a transistor, which are cascode connected with each other. The second amplifier includes a transistor. The transistor has a gate connected to the input terminal, a source connected to ground, and a drain. The transistor has a gate, a source connected to the drain of the transistor, and a drain connected to the output terminal. The transistor has a gate connected to the input terminal, a source connected to ground, and a drain connected to the output terminal.