Differential Class-E Amplifier With Shared Inductor and Output Transformer
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Solution Overview
Problem
Differential class-E power amplifiers require a large number of inductors for harmonic tuning and output matching, making them unsuitable for integrated circuit implementation due to silicon area constraints and difficulties in pre-estimating inductive couplings, which degrades magnetic coupling and quality factor.
Innovation Solution
A differential electronic amplifier design with a reduced number of inductors, utilizing a single symmetrical inductance as a differential resonating load and an output transformer that combines harmonic tuning, output matching, and impedance transformation, isolating the output transformer from DC current with capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of inductors are used for harmonic tuning and output matching in differential class-E amplifiers, then the amplifier performance is improved, but the silicon area increases and integration becomes difficult
Solution Approach 1:
The patent combines multiple inductor functions into a single shared inductor structure. The differential pair shares a common inductor for both harmonic tuning and output matching purposes, eliminating the need for separate inductors for each function. This merging approach maintains the required amplifier performance while dramatically reducing the total silicon area occupied by inductive elements.
Solution Approach 2:
The shared inductor is designed to perform multiple functions simultaneously: it serves as both the harmonic tuning element and the output matching element for the differential class-E amplifier. This multi-functional design allows a single inductor to replace what would traditionally require multiple separate inductors, enabling integration while preserving performance.
2Reliability
If multiple inductors are used in the amplifier circuit, then the magnetic coupling and quality factor are affected, but the device complexity increases
Solution Approach 1:
By merging multiple inductor functions into a single shared inductor, the patent eliminates the complex inductive couplings that would exist between multiple separate inductors. The single inductor structure simplifies the magnetic coupling relationships while maintaining the required quality factor and coupling characteristics for proper amplifier operation.
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
Enables efficient integration on a single chip with improved magnetic coupling and quality factor, reducing the complexity of inductive couplings and allowing for optimized impedance transformation, as demonstrated by simulation results showing low insertion losses and high reflection coefficient at the antenna.
Implementation Method 1
C2 resonates the load at the operating frequency. Capacitor C1 and inductor L5 are placed in series together resulting in a tuned series LC circuit.
Implementation Method 2
an output stage constituted by a first side of a transformer; a load impedance connected to a second side of the transformer
Data Source
AI summary
A differential electronic amplifier including: a first switch connected between a first reference voltage and a first node; a second switch connected between a second reference voltage and a second node; a resonant differential load connected between the first and second nodes and having a centre point connected to a third reference voltage; an output stage constituted by a first side of a transformer; a load impedance connected to a second side of the transformer; a first capacitive element connected between the first side of the transformer and the first node; and a second capacitive element connected between the first side of the transformer and the second node; wherein all inductive elements connected in series between the first and second capacitive elements are inductively coupled to the second side of the transformer.