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EP-4738998-A1 - INTELLIGENT SMART PARALLEL LED-DRIVER DETECTION FOR LOAD SHARING

EP4738998A1EP 4738998 A1EP4738998 A1EP 4738998A1EP-4738998-A1

Abstract

The present invention provides an LED driver for supplying power to an LED load. Said LED driver comprises a droop characteristic defined by a droop characteristic curve, which represents the relationship between an output voltage and an output current of the LED driver, wherein the output voltage decreases as the output current increases. Said LED driver further comprises a control unit configured to autonomously modify the droop characteristic curve without external input.

Inventors

  • Schneider, Miguel Philipp
  • ROMANO, FABIO

Assignees

  • Tridonic GmbH & Co. KG

Dates

Publication Date
20260506
Application Date
20241030

Claims (13)

  1. An LED driver (10) for supplying power to an LED load (11), comprising: a droop characteristic defined by a droop characteristic curve, which represents the relationship between an output voltage and an output current of the LED driver (10), wherein the output voltage decreases as the output current increases; and a control unit configured to autonomously modify the droop characteristic curve without external input.
  2. The LED driver (10) of claim 1, wherein the control unit is configured to shift the droop characteristic curve in order to determine an operating status of the LED driver, the operating status comprising single mode operation or parallel operation, wherein in parallel operation, the LED driver (10) operates in parallel with at least one other LED driver (10).
  3. The LED driver (10) of claim 2, further comprises a measurement unit configured to measure changes in the output voltage and/or output current of the LED driver (10) .
  4. The LED driver (10) of claim 3, wherein the control unit is configured to: determine that the LED driver (10) is in single mode operation when the measured voltage and/or current change is larger than or equal to an expected voltage and/or current change, and determine that the LED driver (10) is in parallel operation when the measured voltage and/or current change is smaller than the expected voltage and/or current change.
  5. The LED driver (10) of claim 4, wherein the control unit is further configured to adjust one or more operational parameters of the LED driver (10), based on the determined operating status of the LED driver (10).
  6. The LED driver (10) of claim 5, wherein the control unit is configured to: flatten the slope of the droop characteristic curve when the LED driver is in single mode operation, or restore the original droop characteristic curve when the LED driver is in parallel operation.
  7. The LED driver (10) of claims 3 to 6, wherein the control unit is further configured to: calculate the total power supplied by the parallelly connected LED drivers based on the measured voltage and/or current changes, and/or determine a number of LED drivers operating in parallel based on the measured voltage and/or current changes.
  8. A LED system (1) comprising: an LED load (11), and at least one LED driver (10) of any preceding claims.
  9. A method (300) for detecting an operation status of an LED drive(10), comprising: measuring (301) an output voltage and/or output current of the LED driver (10); autonomously shifting (302) a droop characteristic curve, which represents the relationship between the output voltage and the output current of the LED driver (10); measuring (303) a change of output voltage and/or a change of output current based on the shifted droop characteristic curve; comparing (304) the measured voltage and/or current change with an expected voltage and/or current change; and determining (305) whether the LED driver (10) is operating in single mode or in parallel with at least one other LED driver (10) based on the comparison of the measured change and the expected change.
  10. The method (300) of claim 9, comprising: determining that the LED driver (10) is operating in single mode when the measured voltage and/or current change is larger than or equal to an expected voltage and/or current change, and determining that the LED driver (10) is in parallel operation when the measured voltage and/or current change is smaller than the expected voltage and/or current change.
  11. The method (300) of claim 9 or 10, comprising: adjusting one or more operational parameters of the LED driver, based on the determined operating status of the LED driver (10).
  12. The method (300) of one of the claims 9 to 11, further comprising: flattening the slope of the droop characteristic curve when the LED driver (10) is operating in single mode, or restoring the original droop characteristic curve when the LED driver (10) is operating in parallel with at least one other LED driver (10).
  13. The method (300) of one of the claims 9 to 12, further comprising: calculating the total power supplied by the parallelly connected LED drivers based on the measured voltage and/or current change, and/or determining a number of LED drivers operating in parallel based on the measured voltage and/or current change.

Description

TECHNICAL FIELD The present invention relates to LED driver technology, specifically to DC-output LED drivers for use in parallel ("stacked") configurations to supply combined DC power to a shared LED load. The invention focuses on methods for determining the operational status of an LED driver, whether functioning independently or as part of a parallel system, without the need for communication between the drivers. BACKGROUND In modern LED lighting systems, multiple LED drivers are often stacked or connected in parallel at their DC output to supply combined DC power to a single LED load. Such configurations are used to meet higher power demands, ensuring redundancy and load-sharing between the parallel drivers. However, in these systems, there is typically no communication between the individual drivers. As a result, each LED driver does not know whether it is operating alone or in parallel with other drivers in the system. This lack of communication poses a challenge, as certain parameters and characteristics of the LED driver, such as output voltage and current regulation, need to be adjusted depending on whether the driver is in single or parallel operation. Traditional LED drivers often rely on "voltage droop control" to balance the load between parallel drivers. Voltage droop control is a technique wherein the output voltage of an LED driver is controlled by its internal control to decrease with increasing output current. This ensures that when multiple drivers are operating in parallel, their loads are balanced by matching their output characteristics. However, conventional LED drivers require pre-configuration or external input to determine their operation mode (single or parallel). The inability to autonomously detect whether a driver is part of a stacked system or operating individually can lead to inefficient operation, improper load balancing, or even system failure in certain cases. SUMMARY In view of the above-discussed limitations, the objective of this invention is to enable an LED driver to independently determine whether it is operating alone or in parallel with other drivers. An additional objective of this invention is to allow the LED driver to dynamically adjust its parameters, thereby optimizing its performance for the current configuration without the need for external communication or configuration. These and other objectives are achieved by the solution of this disclosure as described in the independent claims. Advantageous implementations are further defined in the dependent claims. According to a first aspect of the invention, an LED driver is provided. Said LED driver comprises a droop characteristic defined by a droop characteristic curve, which represents the relationship between an output voltage and an output current of the LED driver, wherein the output voltage decreases as the output current increases. Said LED driver comprises a control unit configured to autonomously modify the droop characteristic curve without external input. The invention provides an LED driver that can autonomously shift its droop characteristic curve without external input. The droop characteristic curve represents how the output voltage is controlled by the internal control of the driver to "droop" when the load current increases. For instance, the voltage is at its highest at no load, and as the load increases, the voltage decreases along the curve, with the slope determining the amount of droop. The autonomous modification of the droop characteristic curve allows the LED driver to dynamically adjust its behavior based on internal conditions. This eliminates the need for external input or communication, simplifying the system design and enabling real-time adaptation to varying load conditions. It provides flexibility in system architecture, allowing the driver to optimize its performance regardless of external configuration. According to a further implementation form of the first aspect of the invention, the control unit is configured to shift the droop characteristic curve in order to determine an operating status of the LED driver, the operating status comprising single mode operation or parallel operation, wherein in parallel operation, the LED driver operates in parallel with at least one other LED driver. This configuration introduces the ability of the control unit to shift the droop characteristic curve to determine the operating status of the LED driver, whether in single mode or in parallel operation with at least one other driver. By shifting its internally stored droop characteristic curve, the driver can self-determine its operating status (single or parallel mode) autonomously. This enables the system to dynamically recognize when it's part of a larger driver network and adapt its operational parameters accordingly. It enhances scalability and provides a basis for efficient load sharing when operating in parallel mode. According to a further implementation form of the first aspect of