RF Transmitter Transformer Feedback to Mitigate Injection Pulling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional RF transmitter circuits, particularly those with digitally controlled oscillators (DCO) and digital power amplifiers (DPA), suffer from efficiency losses due to harmonic distortion and injection pulling, which limit their performance and power efficiency, especially at low supply voltages.
Innovation Solution
The implementation of a feedback capacitor and a matching network transformer in an inverting configuration, along with a magnetically coupled coil, to suppress harmonic distortion and mitigate injection pulling by enhancing feedback coupling and controlling the magnetic coupling factor between the DPA and DCO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a digital power amplifier (DPA) is used to reduce supply voltage and power, then power consumption is reduced, but harmonic distortion occurs at frequencies similar to the DCO operating frequency causing injection pulling
Solution Approach 1:
A feedback capacitor is introduced as an intermediary element between the DPA output and the DCO input. This capacitor creates a feedback path that generates a canceling signal to neutralize the harmonic distortion produced by the DPA, preventing injection pulling while allowing the DPA to operate at reduced power levels
Solution Approach 2:
The patent implements a feedback mechanism where the output of the DPA is fed back through a capacitor to the DCO input. This feedback loop detects the harmonic distortion and automatically generates a counter-signal that cancels the distortion, enabling the system to maintain performance while operating at lower power consumption
2Loss of energy
If the DPA operates at low supply voltage to improve efficiency, then power efficiency is improved, but injection pulling occurs at the DCO
Solution Approach 1:
The feedback capacitor acts as a mediator that allows the system to operate at low supply voltages while maintaining frequency stability. By introducing this intermediary element, the harmful injection pulling effect is canceled, enabling efficient low-voltage operation without sacrificing reliability
3Device complexity
If conventional transmitter circuits are used, then device complexity is low, but efficiency is reduced due to harmonic distortion and injection pulling
Solution Approach 1:
A single feedback capacitor is introduced as a minimal intermediary element into the conventional transmitter circuit. This simple addition creates a feedback path that eliminates harmonic distortion and injection pulling, significantly improving transmitter efficiency while adding minimal complexity to the overall circuit design
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
This solution effectively reduces injection pulling, enhances circuit efficiency, and allows the RF transmitter to operate efficiently at low supply voltages while minimizing harmonic distortion, thereby improving overall performance and extending the lifespan of IoT systems.
Implementation Method 1
The capacitor is electrically coupled between a primary winding and a secondary winding of the matching network transformer. Serving as a feedback capacitor, the capacitor can enhance a feedback coupling from the secondary winding to the primary winding
Implementation Method 2
a magnetically coupled coil, to suppress harmonic distortion and mitigate injection pulling by enhancing feedback coupling and controlling the magnetic coupling factor between the DPA and DCO
Data Source
AI summary
Systems and methods for suppressing and mitigating harmonic distortion in a circuit are disclosed. In one example, a disclosed circuit includes a radio frequency (RF) oscillator and a power amplifier. The RF oscillator is configured to generate an RF signal. The power amplifier is configured to generate an amplified RF signal based on the RF signal. The power amplifier includes a transformer including a primary winding and a secondary winding, and a feedback capacitor electrically coupled to the primary winding and the secondary winding.