Switching Frequency Control via Pseudorandom Signal Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power converters face challenges in effectively controlling switching frequency variations to minimize electromagnetic interference (EMI), often requiring large and expensive analog circuits or limited digital solutions with non-uniform energy spreading.
Innovation Solution
A system and method utilizing a pseudorandom signal generator, digital-to-analog converter, and pulse-width-modulation generator to create frequency variations, which randomize the switching frequency and spread EMI power uniformly across a frequency band, using a digital circuit and M-sequence generator for portable and adaptable frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an analog circuit is used to generate clock jittering for frequency variation, then EMI suppression is improved, but the capacitor area increases and implementation cost increases
Solution Approach 1:
The patent replaces the analog circuit-based clock jittering mechanism with a digital circuit implementation. The digital circuit uses a counter and selective gating to generate frequency variation signals, eliminating the need for large capacitors and expensive analog components while achieving the same EMI suppression effect through digital logic operations.
Solution Approach 2:
The patent changes the state of the frequency variation signal from fixed pattern to scrambled pattern by selectively enabling different counter outputs based on scrambled clock signals. This parameter change in the signal pattern improves energy spreading uniformity across the frequency band while maintaining the digital implementation's area efficiency.
2Ease of manufacture
If a digital circuit with counter is used to generate frequency variation signal, then implementation cost is reduced, but the energy spreading becomes non-uniform due to fixed pattern
Solution Approach 1:
The patent introduces dynamics to the previously static fixed-pattern digital frequency variation by using scrambled clock signals to selectively enable different counter outputs. This makes the frequency variation pattern change over time in a scrambled manner, achieving uniform energy spreading while maintaining the low-cost digital implementation.
Solution Approach 2:
The patent introduces scrambled clock signals as an intermediary mechanism between the counter and the frequency variation output. These scrambled clocks act as a mediator that selects different counter outputs in a scrambled sequence, transforming the fixed pattern into a scrambled pattern that achieves uniform energy spreading without increasing implementation complexity.
3Device complexity
If frequency variation is controlled by external power supply voltage, then the system is simple to implement, but the frequency variation range is limited and design becomes difficult
Solution Approach 1:
The patent segments the frequency control function into discrete digital steps using a counter, allowing independent control of frequency variation magnitude through the counter modulus. This segmentation enables flexible adjustment of frequency variation range by programming the counter without changing the basic circuit structure, achieving both simplicity and adaptability.
Data Source
AI summary
System and method for providing frequency control to a power converter. The system includes a pseudorandom signal generator configured to generate a digital signal. The digital signal is associated with at least an N-bit datum, and N is a positive integer. Additionally, the system includes a digital-to-analog converter configured to receive the digital signal and generate a first control signal, an output signal generator configured to receive the first control signal and generate at least a first output signal associated with a frequency, and a pulse-width-modulation generator configured to receive at least the first output signal. The N-bit datum represents a pseudorandom number.