PWM Waveform Calibration Using Time-Division Clock Multiplexing
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Solution Overview
Problem
Existing methods for generating PWM signals face limitations in precision and adjustability, particularly when there is only one system clock source available, and errors persist even with frequency division, making it difficult to achieve an accurate desired PWM output frequency.
Innovation Solution
A PWM waveform generation device and method utilizing a time-division multiplexing module that receives preprocessing signals from multiple system clock sources, performing time-division and multiplexing processing to generate a PWM output signal with a default standard clock frequency, allowing for precise calibration of the output frequency through adjustments in cycle length and cycle number of the preprocessing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency division coefficient is adjusted to achieve desired PWM output frequency, then frequency accuracy is improved, but errors are inevitable and accurate desired frequency cannot be obtained
Solution Approach 1:
The patent changes the parameter of using multiple clock sources with different frequencies instead of relying on frequency division of a single clock source. By selecting from multiple clock sources with frequencies that are multiples of the target frequency, the system can achieve exact frequency matching without accumulation errors inherent in frequency division methods.
2Measurement precision
If system clock source size is adjusted to obtain accurate PWM output frequency, then frequency accuracy is improved, but the number of system clock sources is constant and cannot be adjusted
Solution Approach 1:
The patent implements a universal clock source selection mechanism that can work with multiple different clock sources (oscillator, RC oscillator, external clock, etc.). The PWM controller is designed to accept various types of clock sources and automatically select the most appropriate one based on the desired output frequency requirements, making the system adaptable to different frequency needs without hardware changes.
3Device complexity
If frequency division is used to generate PWM signal, then PWM signal generation is simple, but working clock precision deteriorates resulting in unstable device operation
Solution Approach 1:
The patent uses multiple low-precision clock sources that can be quickly switched between rather than relying on a single high-precision clock source with frequency division. Each clock source can be used for a specific frequency range and then discarded in favor of another clock source when that range is no longer needed, similar to using disposable objects for specific tasks.
Data Source
AI summary
The PWM waveform generation device comprises a time-division multiplexing module, wherein the time-division multiplexing module is configured for receiving a first preprocessing signal and a second preprocessing signal output by two system clock sources, performing a first time-division processing on the first preprocessing signal to obtain a first time-division signal, and performing a second time-division processing on the second preprocessing signal to obtain a second time-division signal according to a preset strategy, performing multiplexing processing on the first time-division signal and the second time-division signal to obtain a PWM output signal, wherein an output frequency of the PWM output signal is a default standard clock frequency. The present invention has the advantages that the cycle length of one cycle of a PWM waveform depends on cycles of two preprocessing waveforms and the number of the cycles, such that the output waveform frequency may be calibrated to a desired frequency.