Multi-Frequency PWM Resynchronization Using a Quasi-Master Time Base
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing PWM generation technologies fail to maintain synchronization of multi-frequency pulse width modulation signals due to user configuration errors, update errors, and external asynchronous events, leading to loss of initial synchronization among PWM signal outputs.
Innovation Solution
A pulse width modulation generator system utilizing a quasi-master-time-base circuit with phase offset counters, phase comparators, and a synchronization circuit that periodically resynchronizes individual PWM generators to a known reference signal, allowing for minor timing errors and stable synchronized outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If free-running counters are used in PWM generation, then the device complexity is reduced, but synchronization is lost in response to user configuration errors, update errors, and external asynchronous events
Solution Approach 1:
The patent implements a feedback mechanism where the synchronization status of PWM signals is continuously monitored. When desynchronization is detected (through configuration errors, update errors, or external asynchronous events), the system automatically triggers a resynchronization process that resets the counters and aligns all PWM signals to a common reference point, thereby maintaining reliable synchronization without requiring overly complex preventive control mechanisms
Solution Approach 2:
The patent introduces a synchronization controller as an intermediary component that mediates between the free-running counters and the PWM generation process. This controller monitors the synchronization status and intervenes only when necessary to restore synchronization, allowing the counters to operate independently most of the time while ensuring synchronization reliability when needed
2Reliability
If a master time base is used to synchronize all PWM generators, then synchronization reliability is improved, but the device complexity increases due to additional synchronization circuitry
Solution Approach 1:
The patent segments the synchronization function into modular components: individual PWM generators each have their own counters and local control logic, while a separate synchronization controller handles the coordination. This segmentation allows each component to remain relatively simple while the system as a whole achieves reliable synchronization through their coordinated interaction
Solution Approach 2:
The patent implements periodic synchronization checks and corrections, where the synchronization controller periodically monitors the status of PWM signals and triggers resynchronization only when desynchronization is detected. This periodic action approach maintains reliability without requiring continuous complex synchronization circuitry to be actively managing all signals at all times
3Adaptability or versatility
If PWM generators operate independently at different frequencies, then adaptability is improved, but maintaining synchronization across harmonically related frequencies becomes difficult
Solution Approach 1:
The patent designs the PWM generation system with universal control logic that can handle multiple frequencies and harmonically related relationships. The synchronization controller is designed to work with any set of frequencies that share a common base frequency, making the system adaptable to different multi-frequency configurations while maintaining reliable synchronization through its universal synchronization mechanism
Solution Approach 2:
The patent allows the PWM generators to operate with variable frequency parameters while maintaining synchronization through a common reference. The system can dynamically adjust frequency parameters for different PWM channels as long as they maintain harmonic relationships to the base frequency, and the synchronization controller adapts its correction mechanism accordingly to maintain reliability across parameter changes
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A "quasi-master-time-base" circuit is used to periodically resynchronize the individual PWM generators to a know reference signal. This quasi-master-time-base will be at the lowest frequency relative to all of the PWM output frequencies, wherein all of the PWM output frequencies are at the same frequency or at an integer multiple frequency(ies) of the quasi-master frequency. This "quasi-master-time-base" circuit allows for minor timing errors due to user PWM configuration errors and/or update errors, and still yields stable PWM signal outputs that remain synchronized to each other.