Digital Power Amplifier Circuit With Feedback-Controlled Transistor Stacks
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Solution Overview
Problem
Conventional switched capacitor digital power amplifiers (SCDPAs) face limitations in achieving desired output power due to low supply voltage, leading to increased complexity and stress on inverter components, and traditional solutions either increase cell count or supply voltage, resulting in design challenges and inefficiencies.
Innovation Solution
An amplifier circuit with multiple transistor stacks and a feedback circuit that provides proportional feedback signals to control output voltages, allowing for increased supply voltage without stressing inverter components, thereby enhancing output power while maintaining transistor reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If supply voltage is increased to achieve desired output power, then output power is improved, but inverter components experience increased stress and reliability deteriorates
Solution Approach 1:
The amplifier circuit is divided into multiple transistor stacks connected in series, where each stack handles a portion of the total voltage swing. This segmentation allows the supply voltage to be distributed across multiple devices, reducing the stress on any single inverter component while maintaining the desired output power level.
Solution Approach 2:
Multiple transistor stacks serve as intermediary elements between the supply voltage source and the output load. These stacks act as voltage dividers and current mirrors that distribute and control the voltage distribution, allowing high supply voltage to be used without directly stressing the inverter components with the full voltage swing.
2Power
If supply voltage is increased to improve output power, then power efficiency is improved, but device complexity increases due to additional components needed
Solution Approach 1:
The transistor stacks serve multiple functions simultaneously: they act as voltage dividers, current mirrors, and amplification stages. This multi-functionality allows the circuit to achieve high power efficiency without requiring separate dedicated components for each function, thereby limiting the increase in device complexity.
Solution Approach 2:
The invention merges the functions of voltage regulation, current control, and signal amplification into a unified transistor stack architecture. By combining these functions into reusable modular stacks, the circuit achieves high power efficiency without proportionally increasing complexity, as the same structural units perform multiple roles.
3Device complexity
If traditional amplifier circuits are used with low supply voltage, then device simplicity is maintained, but output power remains insufficient
Solution Approach 1:
The amplifier circuit employs dynamic voltage distribution across the transistor stacks, where the voltage swing is dynamically allocated to different stacks based on the signal requirements. This dynamic operation allows the circuit to maintain simplicity in its basic architecture while achieving high output power through efficient voltage utilization during operation.
Data Source
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AI summary
An amplifier circuit may include a plurality of transistors connected in series, the plurality of transistors including: a first transistor of a first conductivity type, a second transistor of the first conductivity type, and a third transistor of the first conductivity type coupled to the first transistor of the first conductivity type and the second transistor of the first conductivity type, the first transistor of the first conductivity type comprising a control terminal to receive a first signal varying between a first upper voltage level and a first lower voltage level; a first transistor of a second conductivity type, a second transistor of the second conductivity type, and a third transistor of the second conductivity type coupled to the first transistor of the second conductivity type and the second transistor of the second conductivity type, the first transistor of the second conductivity type comprising a control terminal to receive a second signal varying between a second upper voltage level and a second lower voltage level; an output terminal coupled to the second transistor of the first conductivity type and the second transistor of the second conductivity type, the output terminal is configured to provide an output signal varying between the first upper voltage level and the second lower voltage level; and a feedback circuit configured to provide signals that are in phase with the output signal to a control terminal of the third transistor of the first conductivity type and to a control terminal of the third transistor of the second conductivity type.