LED Light Generating Device with Switch Matrix for Variable AC Voltage
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Solution Overview
Problem
LED light generating devices face inefficiencies when operated with variable AC voltages, leading to flicker and poor brightness due to mismatched voltage levels, and existing solutions like 'binning' increase manufacturing costs.
Innovation Solution
A light generating device with at least three LED circuits, each equipped with a controllable current regulator and connected through a switch matrix, which can switch between series and parallel configurations based on the detected AC voltage, allowing precise current control and adaptation to varying voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plurality of LEDs is connected in series to match mains voltage, then the voltage compatibility is improved, but optical flicker occurs and current flow angle is reduced due to AC waveform limitations
Solution Approach 1:
The LED string is divided into multiple groups that can be independently controlled. Each group can be switched on or off based on the instantaneous AC voltage level, allowing the device to maintain stable light output across different phases of the AC waveform and eliminate flicker while maintaining voltage compatibility.
Solution Approach 2:
The patent implements dynamic switching of LED groups based on real-time detection of AC voltage instantaneous values. The controller adjusts which LED groups are active during different phases of the AC cycle, enabling the system to adapt to varying voltage conditions and maintain consistent illumination without flicker.
2Adaptability or versatility
If a device designed for 230V mains is operated with 120V, then the device can be used in different voltage systems, but visible flicker and poor brightness occur due to voltage mismatch
Solution Approach 1:
The controller dynamically adjusts the switching configuration of LED groups based on the detected mains voltage level (120V or 230V). By recognizing the voltage system and appropriately configuring which LED groups are activated, the device maintains optimal brightness and eliminates flicker across different voltage standards.
Solution Approach 2:
The patent designs the LED light generating device to universally support multiple mains voltage systems (both 120V and 230V) through a single configuration. The switch matrix and controller work together to provide multi-functionality, allowing the same device to operate optimally in different voltage environments without requiring separate hardware versions.
3Reliability
If a device designed for 120V is operated with 230V mains voltage, then flicker may be reduced, but large amounts of energy are dissipated by linear regulator or bleeder circuit
Solution Approach 1:
Instead of using a linear regulator or bleeder circuit to handle surplus voltage, the patent segments the LED string into multiple groups and selectively activates only the necessary groups based on the input voltage level. This approach eliminates the need for energy-dissipating components by directing excess voltage away from the LED circuit entirely.
Solution Approach 2:
The patent effectively discards the surplus voltage by not routing it through energy-dissipating components. Instead, the switch matrix configuration selectively connects only the appropriate number of LED groups to match the input voltage, recovering what would have been wasted energy and improving overall system efficiency.
4Illumination intensity
If selected or binned LEDs are used to adapt to different voltage levels, then the light output quality is improved, but manufacturing costs increase noticeably
Solution Approach 1:
The patent divides the LED string into multiple groups that can be independently controlled, eliminating the need for expensive binning processes. By using standard LEDs and controlling them in groups through a switch matrix, the system achieves consistent light output quality without the additional manufacturing costs associated with selecting and sorting individual LEDs by their electrical characteristics.
Solution Approach 2:
Instead of changing the physical or electrical parameters of individual LEDs through binning, the patent changes the operational parameters by controlling which LED groups are active. This approach maintains light output quality while using standard, unsorted LEDs, thereby reducing manufacturing costs.
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4D
AI summary
A light generating device (1) is provided with at least a voltage input (21) adapted for receiving a variable voltage, at least three LED circuits (10), coupled with said voltage input (21), wherein each LED circuit (10) comprises a LED unit (14) and controllable current regulator (15) to control the current through said LED circuit (10). The light generating device (1) further comprises a controllable switch matrix (30) comprising a plurality of switches (25, 26, 27), said switch matrix (30) is configured to operate in at least three different switching modes and a controller (50), connected at least with said switch matrix (30), configured to determine said variable operating voltage and to control the switching mode of said switch matrix (30) in dependence of the determined operating voltage. To provide an efficient operation of such device (1) with a variable operating voltage, such as an AC voltage, in a first switching mode, said LED units (10) are connected parallel to each other, in a second switching mode, at least two of said LED units (10) are connected in series and in a third switching mode, said LED units 10 are connected in series with each other.