Switched-Capacitor RF Power Amplifier With Parallel Charge-Control Stages
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Solution Overview
Problem
Current CMOS technology faces challenges in integrating a power amplifier due to difficulties in achieving high output power, energy efficiency, and linearity, leading to complex designs and high power consumption.
Innovation Solution
The development of a Switched-Capacitor Radio Frequency Power Amplifier (SCPA) architecture that controls charge transfer in multiple stages with storage elements, using phase and amplitude information to drive a switch-based amplification, allowing for efficient and accurate amplification without requiring extensive analog/mixed signal circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional CMOS power amplifier designs are used, then integration is achieved, but achieving desirable operating characteristics (high output power, high energy efficiency, and sufficient linearity) becomes difficult
Solution Approach 1:
The power amplifier is divided into multiple parallel amplifier stages, each contributing to the overall output. This segmentation allows the system to achieve high output power through constructive combination of multiple smaller amplification paths while maintaining CMOS integration benefits.
Solution Approach 2:
The amplifier employs periodic switching of MOSFETs between different states (on/off, different impedance levels) to achieve efficient power amplification. This periodic switching enables the system to operate in switching modes that improve energy efficiency while maintaining linearity through controlled impedance transformation.
2Use of energy by moving object
If MOSFETs are scaled to switch at higher speeds with lower dynamic power consumption, then energy efficiency increases, but higher impedance transformation ratio is required to produce given output power
Solution Approach 1:
Multiple amplifier stages are combined in parallel, each contributing to the overall output power. This merging approach allows the system to achieve high output power without requiring excessive impedance transformation ratios, as the combined output of multiple stages provides the necessary power level.
Solution Approach 2:
The patent transitions from single-stage to multi-stage parallel architecture, adding a dimensional aspect to the power amplification approach. This dimensional change (from one amplification path to multiple parallel paths) enables efficient power delivery without excessive impedance transformation requirements.
3Adaptability or versatility
If CMOS switches are used in power amplifiers, then integration is achieved, but additional circuits are required to modulate output signal level, leading to complex designs with large chip areas and high power consumption
Solution Approach 1:
The amplifier stages utilize the inherent switching characteristics of CMOS devices to perform both switching and amplification functions. The MOSFETs serve multiple roles (switching element, amplification element, impedance transformation element), eliminating the need for separate modulation circuits and reducing overall chip area and power consumption.
Solution Approach 2:
The CMOS MOSFETs are designed to perform multiple functions simultaneously: switching, amplification, and impedance transformation. This multi-functionality reduces the need for additional dedicated circuits, thereby reducing chip area and power consumption while maintaining integration benefits.
4Measurement precision
If digital power amplifiers use parallel amplifier stages to modulate effective gain, then small output linearity is achieved, but saturation occurs for large outputs requiring additional circuitry
Solution Approach 1:
The parallel amplifier stage architecture segments the power amplification function across multiple paths. Each stage operates in a linear region for its portion of the output, and the combined output maintains linearity over a wider range. This segmentation prevents saturation by distributing the amplification load across multiple stages.
Solution Approach 2:
The amplifier employs dynamic control of the parallel stages, where the contribution of each stage to the overall output is dynamically adjusted based on the input signal level. This dynamic operation allows the system to maintain linearity across both small and large output swings without requiring additional linearization circuitry.
Data Source
AI summary
Disclosed herein is an improved power amplifier, referred to as a Switched-Capacitor Radio Frequency Power Amplification (SCPA). The SCPA may be fabricated with scale CMOS technology. The SCPA may include a plurality of stages, each stage including a storage device, a switch, and selection circuitry. Various combinations of the stages may produce an output signal based on characteristics of a reference signal to be amplified. The output from the stages may be combined to create an amplified approximate square wave. The amplified square wave may be filtered by output circuitry such as a bandpass matching circuit, resulting in an output signal that may be an amplified version of the reference signal.