RF Amplifier Circuit With Switchable Hybrid Power Combining
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Solution Overview
Problem
Current amplifier circuits face challenges in achieving high power efficiency, particularly in mobile phone applications, due to power combining losses and inefficiencies in power handling as output power increases.
Innovation Solution
The proposed amplifier circuit design includes a first and second amplifier, phase shifter circuits, inductors, capacitors, and a switchable resistor configuration, allowing for phase shifting and efficient power combining through a 90° hybrid structure, enabling operation in both balanced and Doherty modes to enhance tolerance to load variations and increase efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional power combining structure (resistor, inductor, inductor) is used, then power combining is achieved, but power combining losses increase and efficiency decreases
Solution Approach 1:
The patent applies the dynamics principle by making the resistor connection switchable through a switch element. The resistor can be dynamically connected or disconnected from the power combining network based on operating conditions. This dynamic configuration allows the circuit to optimize between power combining mode (resistor connected) and high-efficiency mode (resistor disconnected), thereby reducing power combining losses and improving overall amplification efficiency across different power levels.
2Power
If output power is increased to meet high power performance demands, then power output is improved, but efficiency deteriorates due to power handling losses
Solution Approach 1:
The switchable resistor configuration enables dynamic adaptation to different power levels. At lower power levels, the resistor is connected to provide proper power combining and impedance matching. At higher power levels, the switch disconnects the resistor to eliminate unnecessary power dissipation and reduce power handling losses, thereby maintaining high efficiency across the full power range while still achieving high output power capability.
3Reliability
If a fixed resistor connection is used for power combining, then impedance matching is achieved, but tolerance to load variations decreases
Solution Approach 1:
The switchable resistor configuration provides dynamic impedance adjustment capability. By selectively connecting or disconnecting the resistor, the circuit can adapt its impedance characteristics to match different load conditions. This enhances tolerance to load variations as the circuit can reconfigure itself based on the actual load state, improving reliability without requiring overly complex adaptive impedance matching networks.
Data Source
AI summary
An amplifier circuit includes an inductor coupled to an amplifier, an inductor coupled to an amplifier, an inductor provided in series in a first output path connecting the amplifier and the inductor, a capacitor coupled to the first output path and the ground, a capacitor provided in series in a second output path connecting the amplifier and the inductor, an inductor coupled to the second output path and the ground, and a first circuit coupled between a first path connecting the inductors and a second path connecting the capacitor and the inductor.