Lighting Controller Zero Crossing Synchronization
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Solution Overview
Problem
Prior multichannel dimmers face issues with manufacturing costs and potential malfunctions due to the need for dedicated timing lines and optoisolators for zero voltage detection, and suffer from jitter in zero voltage detection, leading to variations in lighting intensity, especially when driving LED lights.
Innovation Solution
A lighting controller design where the master processor observes zero crossing points in alternating current and transmits control commands to slave processors on an internal control bus in a predetermined relationship with these points, eliminating the need for separate timing lines and using digital filtering to reduce jitter, allowing accurate phase-cutting of AC half-waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated timing lines and optoisolators are used to convey zero voltage detection information to slave processors, then reliability of timing information transmission is improved, but manufacturing costs increase and device complexity increases
Solution Approach 1:
The patent merges the timing information transmission with the existing control command transmission by embedding timing data in the least significant bits of control commands on the shared control bus. This eliminates the need for separate dedicated timing lines and optoisolators, reducing device complexity while maintaining reliable timing information delivery to slave processors.
Solution Approach 2:
The control bus is given multi-functionality by using it for both control command transmission and timing information conveyance. The same communication infrastructure serves dual purposes, eliminating redundant components and simplifying the overall system architecture while ensuring reliable timing delivery.
2Measurement precision
If dedicated timing lines with optoisolators are used for zero voltage detection, then timing accuracy is improved, but manufacturing costs increase
Solution Approach 1:
The patent combines timing information with control commands in the same data stream on the control bus. By embedding timing data in the least significant bits of control commands, the system achieves accurate timing delivery without requiring expensive dedicated timing lines and optoisolators, significantly reducing manufacturing costs.
Solution Approach 2:
The timing information is copied into the control command data structure as additional bits. This allows the timing data to be transmitted alongside control commands using the existing communication infrastructure, avoiding the need for separate expensive timing transmission paths while maintaining measurement precision.
3Speed
If zero voltage detection is performed without digital filtering, then response speed is improved, but jitter in timing detection increases causing lighting intensity variation
Solution Approach 1:
The patent implements digital filtering of the zero voltage detection signal to reduce jitter. The filtered timing information is then embedded in control commands and transmitted to slave processors, providing stable and consistent timing references that eliminate lighting intensity variations while maintaining adequate response speed through efficient filtering algorithms.
Data Source
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AI summary
A lighting controller comprises an operating power input for receiving alternating current, a master processor, and one or more slave processors. Each slave processor is configured to use respective switching components to manipulate half-waves of alternating current for outputting a phase-cut alternating current. An internal control bus conveys control commands indicative of desired extent of said manipulating from the master processor to the slave processors. The master processor is configured to time transmissions of control commands on the internal control bus in a predetermined relationship with zero crossing points between half-waves of the alternating current.