Parallel Doherty Amplifier Bias Control for Low-Power Efficiency
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Solution Overview
Problem
Conventional Doherty power amplifiers experience limited improvement in power amplification efficiency when operating in low output power ranges, which hinders energy savings and consumption reduction in wireless communication systems.
Innovation Solution
A method and device that adjust gate voltages of main and peak power amplifiers in a Doherty power amplifier using a bias circuit, causing the peak power amplifiers to be in an off state and the main power amplifiers to operate in both main and peak power amplification states, thereby optimizing efficiency in low output power ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the conventional Doherty power amplifier adjusts drain voltage or gate voltage to improve efficiency at low output power, then power amplification efficiency is improved slightly, but the improvement is less than 10% and insufficient for significant energy savings
Solution Approach 1:
The patent divides the power amplifier system into two parallel paths (first path and second path), each containing main and peak power amplifiers. This segmentation allows independent control of each path, enabling the system to optimize efficiency at low output power by selectively activating only necessary amplifiers in one path while keeping others in off state, thereby achieving significant energy savings beyond the conventional 10% improvement.
2Reliability
If the peak power amplifier operates in class C and main power amplifier operates in class AB, then the amplifier maintains relatively high efficiency within a large input signal power range, but power consumption remains high when operating in low output power range
Solution Approach 1:
The patent implements dynamic control by adjusting gate voltages of main and peak power amplifiers based on real-time output power levels. When output power is within low output power range, the control circuit adjusts voltages to cause peak power amplifiers to enter off state while maintaining main power amplifiers in active state, thereby dynamically adapting power consumption to actual operating conditions and significantly reducing energy waste at low power levels.
Solution Approach 2:
The patent changes the operating state parameters of power amplifiers by adjusting gate voltages. Specifically, it transitions peak power amplifiers from active operating states to off state, and maintains main power amplifiers in appropriate amplification states, thereby changing the overall power consumption parameters of the system to achieve lower energy consumption at low output power ranges.
Data Source
AI summary
One aspect of the present invention provides a method for improving power amplification efficiency of a Doherty power amplifier. The method is applied to a Doherty power amplifier that has two paths of Doherty circuit units connected in parallel. The method includes: when output power of the Doherty power amplifier is within a low out power range, adjusting, by a bias circuit, gate voltages of main power amplifiers and peak power amplifiers in the two paths of Doherty circuit units connected in parallel, in order to cause the peak power amplifiers to be in an off state, and the main power amplifiers in the two paths of Doherty circuit units connected in parallel to be in a main power amplification state and a peak power amplification state respectively.