Parallel Power Amplifier Gain Control With Lower Output Current
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Solution Overview
Problem
Conventional power amplifiers face challenges in adjusting gain and reducing output current efficiently, leading to degraded power added efficiency (PAE) when operating in gain reduction and backoff modes, and existing methods fail to effectively reduce output current while adjusting gain.
Innovation Solution
The amplifying apparatus includes multiple amplifying circuits and an adjusting circuit, where control signals determine operating modes to adjust gain and output current, enabling selective enabling/disabling of amplifying circuits and adjusting bias voltages to manage linear power and output current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the gain of the power amplifier is reduced by changing the bias, then the gain adjustment is achieved, but the output current cannot be reduced and the PAE is not improved
Solution Approach 1:
The power amplifier is divided into multiple parallel amplifying circuits (first amplifying circuit and second amplifying circuit) that can be independently controlled. By selectively enabling or disabling specific circuits through control signals, the gain and output current can be adjusted in discrete steps without requiring continuous bias changes, thereby reducing output current while maintaining PAE improvement.
Solution Approach 2:
The system dynamically switches between different operating modes by controlling the enable/disable state of amplifying circuits based on the control signal. This dynamic reconfiguration allows the amplifier to adapt its gain and output current characteristics in real-time, resolving the contradiction between gain adjustment and output current reduction.
2Ease of operation
If an attenuator is used at the input terminal to change the gain, then the gain adjustment is achieved, but the output current of the power amplifier cannot be reduced
Solution Approach 1:
The attenuator is removed from the system and replaced by a selective switching mechanism that directly controls which amplifying circuits are active. This extraction eliminates the energy loss associated with attenuation while achieving the same gain adjustment function through circuit selection, thereby reducing both power consumption and maintaining gain control capability.
Solution Approach 2:
A control signal acts as an intermediary between the input and the amplifying circuits, selectively enabling or disabling specific circuits based on the desired gain level. This intermediary mechanism allows for direct control of output current without requiring an attenuator, thus reducing energy loss while achieving gain adjustment.
3Ease of operation
If the power amplifier operates in gain reduction and backoff mode, then the gain is reduced, but the PAE drops and characteristics are degraded
Solution Approach 1:
Different amplifying circuits are designed with different local characteristics (e.g., different gain levels, different efficiency characteristics). By selectively activating specific circuits with favorable local qualities for the current operating condition, the system can maintain high PAE even when operating in gain reduction and backoff modes, rather than uniformly degrading all circuit characteristics.
Data Source
AI summary
The disclosure provides an amplifying apparatus including a plurality of amplifying circuits and an adjusting circuit. The input terminals of the amplifying circuits are coupled to a first common node. The output terminals of the amplifying circuits are coupled to a second common node. The adjusting circuit adjusts an input signal to generate an adjusted signal to the first common node; the adjusting circuit adjusts the signal of the second common node; or the adjusting circuit adjusts the input signal to generate the adjusted signal to the first common node and adjusts the signal of the second common node. The first control signal and the second control signal respectively control the amplifying circuits and the adjusting circuit to determine the gain, the linear power, and the output current of the amplifying apparatus.