Cascode Power Amplifier Circuit for Higher Output Without Voltage Boost
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Solution Overview
Problem
Power amplifier circuits in mobile communication devices face limitations in maximum output power due to restricted power supply voltage, requiring booster conversion circuits that increase the circuit scale.
Innovation Solution
A power amplifier circuit design incorporating a cascode configuration with bipolar transistors and a voltage adjusting circuit, which allows for increased signal amplitude without boosting the power supply voltage, thereby enhancing output power and efficiency without significant circuit scale expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a booster conversion circuit is added to increase power supply voltage, then maximum output power increases, but circuit scale increases
Solution Approach 1:
The power amplifier circuit is divided into two stages: a drive amplifier stage and a power amplifier stage. The drive amplifier generates an amplified signal with higher voltage swing, which then drives the power amplifier stage. This segmentation allows the power amplifier to achieve higher output power without requiring a booster conversion circuit, thus avoiding increase in circuit scale.
Solution Approach 2:
The invention changes the operating parameters of the power amplifier by using a cascode configuration with specific biasing arrangements. The power supply voltage is optimized to be within the range of 2.7V to 5.5V, and the circuit parameters are designed to maximize voltage swing and output power within this constrained voltage range, eliminating the need for voltage boosting.
2Power
If power supply voltage is increased beyond maximum battery voltage, then maximum output power increases, but additional conversion circuits are required
Solution Approach 1:
The power amplifier circuit employs dynamic biasing and operating point optimization to maximize output power within the available battery voltage range. The circuit dynamically adjusts operating conditions to achieve peak efficiency and maximum power output without requiring voltage conversion, simplifying implementation.
Data Source
AI summary
A power amplifier circuit includes a first transistor, a second transistor, a first bias circuit supplying a first bias current or voltage, a second bias circuit supplying a second bias current or voltage, a first inductor, and a first capacitor. A power supply voltage is supplied to a collector of the first transistor, and an emitter thereof is grounded. A radio frequency signal and the first bias current or voltage are supplied to a base of the first transistor. The power supply voltage is supplied to a collector of the second transistor, and an emitter thereof is connected to the collector of the first transistor via the first capacitor and is grounded via the first inductor. The second bias current or voltage is supplied to a base of the second transistor. An amplified radio frequency signal is output from the collector of the second transistor.