Power Converter Jitter Modulation Near Switching Frequency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switched mode power converters face challenges in effectively modulating jitter signals to optimize switching frequency and reduce noise, leading to inefficiencies in power conversion and increased audible noise.
Innovation Solution
Incorporating a jitter generator within the controller of a switched mode power converter, which modulates the jitter signal by adjusting its frequency through a timer circuit and logic gates, allowing for dynamic control of switching parameters such as frequency, duty cycle, and current limits, thereby optimizing energy transfer and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the switching frequency is increased to improve power conversion efficiency, then the power conversion efficiency is improved, but audible noise increases when the switching frequency approaches the jitter frequency
Solution Approach 1:
The jitter frequency is dynamically adjusted based on the switching frequency. When the switching frequency approaches the jitter frequency, the controller automatically modulates the jitter signal frequency to maintain separation, ensuring continuous noise reduction without sacrificing power conversion efficiency across varying operating conditions
Solution Approach 2:
The system changes the frequency parameter of the jitter signal dynamically. The jitter frequency is modified in response to switching frequency changes, allowing the system to adapt to different operating points and maintain optimal performance while avoiding audible noise generation
2Device complexity
If a fixed jitter frequency is used to simplify control, then the device complexity is reduced, but power conversion efficiency decreases when switching frequency approaches jitter frequency
Solution Approach 1:
The controller monitors the switching frequency and uses this feedback to automatically adjust the jitter signal frequency. This closed-loop approach maintains optimal separation between switching and jitter frequencies without requiring complex external control circuits, achieving adaptive optimization with minimal additional complexity
3Device complexity
If the jitter signal frequency is not modulated, then the device complexity is reduced, but audible noise increases near the switching frequency
Solution Approach 1:
The jitter generator is integrated within the existing controller architecture, combining the jitter signal generation and frequency modulation functions into a single unified circuit. This merging approach reduces overall device complexity while maintaining the capability to modulate jitter frequency for noise reduction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A controller for use in a power converter includes a jitter generator circuit coupled to receive a drive signal from a switch controller and generate a jitter signal. The switch controller is coupled to a power switch coupled to an energy transfer element. The switch controller is coupled to receive a current sense signal representative of a drain current through the power switch. The switch controller is coupled to generate the drive signal to control switching of the power switch in response to the current sense signal and the jitter signal to control a transfer of energy from an input of the power converter to an output of the power converter.