LED Driver AC Signal Detection for Frequency and Peak Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lighting systems lack an efficient method to detect and measure the frequency and amplitude of an AC voltage, particularly for mains voltage, which is crucial for determining the operational mode of lighting devices, including emergency lighting.
Innovation Solution
A driver for lighting systems that includes input terminals for AC or DC voltage, output terminals for LED loads, a detection circuitry to obtain signals representing the frequency and amplitude of the AC voltage, and a control circuit that processes these signals to adapt the driver's operation parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional DC/AC detection circuitries are used with threshold comparisons, then the presence or non-presence of AC voltage can be detected, but the frequency and amplitude measurement capability is insufficient
Solution Approach 1:
The detection circuitry is designed to perform multiple functions: it detects AC/DC voltage presence, measures frequency, and measures amplitude using a single integrated circuit configuration. This eliminates the need for separate detection circuits for each parameter, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent introduces an intermediary signal processing approach where the detection circuitry converts voltage measurements into timing information (time duration between zero crossings). This intermediary representation allows accurate frequency and amplitude measurement without requiring complex direct measurement circuits, thus reducing overall circuit complexity while maintaining high measurement precision.
2Measurement precision
If a primary side controller is used to obtain AC voltage signals, then accurate voltage detection is achieved, but component count and cost increase
Solution Approach 1:
The patent extracts the voltage detection function from the primary side controller and relocates it to the secondary side. By removing the primary side controller's detection burden and implementing detection circuitry on the secondary side instead, the system achieves accurate AC voltage signal detection while reducing the overall component count and eliminating the need for a separate primary side controller.
Solution Approach 2:
The secondary side of the driver is made self-sufficient by equipping it with its own detection circuitry that can independently measure AC voltage characteristics. This self-service approach eliminates the need for a primary side controller to provide voltage information, reducing component count while maintaining measurement precision.
3Reliability
If emergency lighting detection is implemented without frequency and amplitude measurement, then simple operation is maintained, but reliable emergency mode activation cannot be ensured
Solution Approach 1:
The detection circuitry continuously monitors and measures frequency and amplitude parameters in advance, maintaining these measurements ready for immediate evaluation. This preliminary action ensures that when emergency mode activation is needed, the system already has the necessary voltage characteristic data to reliably determine whether to activate emergency lighting, without adding complex operational steps.
Solution Approach 2:
The control circuit receives continuous feedback from the detection circuitry regarding frequency and amplitude measurements. This feedback mechanism automatically provides the information needed for reliable emergency mode activation decisions, maintaining ease of operation while ensuring high reliability through continuous monitoring and automatic evaluation of voltage characteristics.
Data Source
AI summary
The disclosure relates to a driver for lighting means (100) comprising: input terminals (101a, 101b) for an optionally rectified AC voltage; output terminals (104a, 104b) for supplying a LED load (105), a detection circuitry (102) connected to the input terminals (101a, 101b), configured to obtain a signal representing a frequency of the AC voltage and an amplitude of the peak of each cycle of the AC voltage, and a control circuit (103) being connected to the detection circuitry (102) and supplied with said signal.