Bipolar Power Amplifier Switching Without Cascode Linearity Limits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power amplification circuits face challenges in handling large signals due to restricted amplitude and linearity issues, leading to signal distortion and increased circuit area when using cascode-connected bipolar transistors.
Innovation Solution
A power amplification circuit design that employs a single bipolar transistor with a DC-grounded emitter and AC-grounded base, controlled by a control circuit supplying DC control voltage or current, allowing for efficient switching and reducing circuit area by eliminating the need for cascode connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two bipolar transistors are cascode connected to form a high-frequency switch, then the switch can control signal transmission, but the output signal amplitude is restricted by saturation voltages and the circuit area increases
Solution Approach 1:
The patent extracts the switching control function from the cascode-connected two-transistor configuration and implements it using a single bipolar transistor. By removing the redundant second transistor and its associated cascode connection, the circuit achieves the same switching control capability with reduced component count and smaller circuit area.
Solution Approach 2:
The patent merges the functions of two separate transistors into a single bipolar transistor. The single transistor integrates both the switching control function and the signal transmission function that were previously distributed across two cascode-connected transistors, thereby reducing circuit complexity and area.
2Reliability
If two bipolar transistors are cascode connected, then switching control is achieved, but the output signal amplitude is restricted and linearity characteristics deteriorate
Solution Approach 1:
The patent removes the second transistor from the cascode connection, eliminating the saturation voltage restriction that limited output signal amplitude. By extracting this redundant component, the single transistor configuration allows for larger output signal amplitudes and improved linearity characteristics while maintaining switching control capability.
3Area of stationary object
If a single bipolar transistor is used instead of cascode connection, then circuit area is reduced, but switching control capability must be maintained
Solution Approach 1:
The patent combines multiple functions (switching control and signal transmission) into a single bipolar transistor configuration. This merging eliminates the need for cascode connections while maintaining the essential switching control capability through proper biasing and circuit design.
Data Source
AI summary
Provided is a power amplification circuit that includes: a first transistor that has an emitter to which a first radio frequency signal is supplied, a base to which a first DC control current or DC control voltage is supplied and a collector that outputs a first output signal that corresponds to the first radio frequency signal; a first amplifier that amplifies the first output signal and outputs a first amplified signal; and a first control circuit that supplies the first DC control current or DC control voltage to the base of the first transistor in order to control output of the first output signal.