Modular CMOS Power Amplifier With Parallel Gain Control
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Solution Overview
Problem
CMOS transistors in radio transmitters face limitations such as lower trans-conductance, breakdown voltage, and passive component performance, leading to higher current consumption, limited power supply, and challenges in power tuning and isolation, which affect signal amplification and frequency conversion.
Innovation Solution
A modular amplifier structure with gain-controlled amplifier sub-units using CMOS transistors, where local oscillator signals control the activation and disabling of amplifier sub-units to adjust amplification, and a combining circuit with capacitors and a coil provides enhanced voltage gain without excessive passive component usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If CMOS transistors are used in amplifiers, then integration level and manufacturing cost are improved, but trans-conductance and breakdown voltage decrease leading to higher current consumption and limited power supply
Solution Approach 1:
The amplifier is divided into multiple parallel amplifier sub-units, each with its own CMOS transistor. By selectively activating subsets of these sub-units, the amplifier achieves variable gain while maintaining efficient current utilization. Each sub-unit operates at optimal current levels, avoiding the need for a single high-current transistor.
Solution Approach 2:
The amplifier dynamically switches between different subsets of amplifier sub-units based on the required signal level. This dynamic reconfiguration allows the system to adapt current consumption to the actual signal requirements, consuming more current only when high signal levels are needed.
2Ease of manufacture
If CMOS transistors are used in amplifiers, then manufacturing advantages are improved, but breakdown voltage decreases leading to limited power supply and output swing
Solution Approach 1:
The voltage swing requirement is segmented across multiple amplifier sub-units. Each sub-unit operates within a limited voltage range determined by the CMOS breakdown voltage, but the parallel combination of multiple sub-units delivers the required total power and voltage swing capability.
Solution Approach 2:
Multiple amplifier sub-units with limited individual power capability are merged in parallel to achieve the required total power output. The combining circuit merges the outputs of multiple sub-units, each operating within safe voltage limits, to produce the necessary overall power and voltage swing.
3Device complexity
If isolation is reduced in CMOS amplifiers, then manufacturing simplicity is improved, but power tuning range and accuracy deteriorate
Solution Approach 1:
The power tuning function is segmented across multiple independently controllable amplifier sub-units. Each sub-unit can be individually activated or deactivated, providing fine-grained control over the total power output. This segmented approach enables accurate power tuning without requiring complex isolation networks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves efficient amplification and frequency conversion with improved power handling, reduced power consumption, and minimal signal leakage, addressing the limitations of CMOS transistors while maintaining low output impedance and isolation.
Implementation Method 1
a combining circuit with capacitors and a coil provides enhanced voltage gain
Data Source
Figure 1~5
Figure 3~4B
AI summary
There is provided a modular amplifier structure comprising a plurality of parallel amplifier sub-units (208). Each amplifier sub-unit is configured to amplify a received payload signal under control of at least one received control signal. Outputs of the amplifier sub-units are applied to a combining circuit (218). The combining circuit is configured to combine the outputs of the plurality of amplifier sub-units to provide an amplified payload signal.