Integrated Doherty Amplifier Matching Without Hybrid Splitters
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Solution Overview
Problem
Conventional Doherty power amplifiers face challenges in miniaturization and integration due to high production costs and size limitations, particularly due to the use of quarter-wave transformers and 3 dB 90° hybrid splitters, which hinder their integration on a single chip while maintaining efficiency and linearity.
Innovation Solution
The proposed solution involves an improved output and input matching method for Doherty power amplifiers, reducing the number of passive devices and using a bonding inductor for impedance control, allowing for a more compact design and efficient power division between the carrier and peaking amplifiers, enabling further miniaturization and integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quarter-wave transformers and 3 dB 90° hybrid splitters are used in conventional Doherty power amplifiers, then load line impedance control and power division are achieved, but device size and production cost increase significantly
Solution Approach 1:
The patent extracts and removes the 3 dB 90° hybrid splitter from the conventional Doherty amplifier structure. Instead of using a hybrid splitter for power division, the invention directly connects the input end of the carrier amplifier to the input end of the peaking amplifier, eliminating the need for this passive device and reducing chip area.
Solution Approach 2:
The patent makes the input matching circuits serve multiple functions. The input matching circuits not only perform impedance matching but also provide power division functionality that was previously handled by the hybrid splitter, allowing the same circuit elements to fulfill multiple roles in the amplifier operation.
2Reliability
If quarter-wave transformers are used for impedance control, then load line impedance is controlled, but the number of passive devices and production cost increase
Solution Approach 1:
The patent merges the impedance control function with the output matching circuits. The output matching circuits are designed to provide both impedance matching and load line impedance control, eliminating the need for separate quarter-wave transformer components and reducing the total number of passive devices required.
Solution Approach 2:
The output matching circuits are designed to perform multiple functions simultaneously: impedance matching and load line impedance control. This multi-functionality reduces the need for dedicated quarter-wave transformers and other separate passive components, simplifying the overall device structure.
3Power
If conventional Doherty amplifier structure is used, then power amplification is achieved, but integration on single chip is difficult due to size and inductor loss
Solution Approach 1:
The patent extracts and removes several passive devices including quarter-wave transformers and hybrid splitters from the conventional structure. This reduction in passive components, particularly inductors which have high loss and large area, makes chip-scale integration feasible while maintaining the power amplification function.
Solution Approach 2:
The patent segments the amplifier into carrier amplifier and peaking amplifier blocks with direct input connections. This segmentation allows each block to be optimized independently and integrated more efficiently on a single chip, reducing the overall area and inductor loss associated with conventional integrated structures.
Data Source
AI summary
The present invention relates to a power amplifier; and, more particularly, to a Doherty power amplifier. The power amplifier includes at least one carrier amplifier; at least one peaking amplifier arranged in parallel with the carrier amplifier in such a manner that the carrier amplifier and the peaking amplifier collectively operate as a Doherty amplifier; a plurality of input matching circuits, at least one of which is respectively connected to an input ends of the carrier amplifier and the peaking amplifier; at least one impedance control circuit, each of which is connected to an output end of each carrier amplifier for controlling a load line impedance of the said each carrier amplifier; at least one output matching circuit directly or indirectly connected to output ends of the impedance control circuit and the peaking amplifier; and at least one first delay circuit for matching delays between the carrier amplifier and the peaking amplifier. The present invention provides an improved Doherty power amplifier capable of achieving a further miniaturization and integration while maintaining an advantage in terms of efficiency and linearity of a Doherty power amplifier by employing an improved output and input matching method, and capable of operating more similar to the ideal operation of a Doherty power amplifier by applying an improved input power division method thereto.