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EP-4739003-A1 - LED SYSTEM WITH INTEGRATED HUMIDITY SENSING CAPABILITY

EP4739003A1EP 4739003 A1EP4739003 A1EP 4739003A1EP-4739003-A1

Abstract

The present invention provides a LED system (10). Said LED system (10) comprises: a LED driver (11) providing a LED supply voltage (12) at its output terminals (13, 14), a LED load (15) supplied off the output terminals (13, 14) of the LED driver (11), and a humidity sensor (16) having two terminals and being connected in parallel to the LED load (15). The LED driver (11) comprises a controller designed for reading out a humidity information voltage signal via a voltage present at its output terminals (13, 14).

Inventors

  • BAKK, ISTVAN
  • Mozsáry, András

Assignees

  • Tridonic GmbH & Co. KG

Dates

Publication Date
20260506
Application Date
20241104

Claims (15)

  1. A LED system (10) comprising: a LED driver (11) providing a LED supply voltage (12) at its output terminals (13, 14), a LED load (15) supplied off the output terminals (13, 14) of the LED driver (11), and a humidity sensor (16) having two terminals and being connected in parallel to the LED load (15), wherein the LED driver (11) comprises a controller designed for reading out a humidity information voltage signal via a voltage present at its output terminals (13, 14) .
  2. The LED system (10) of claim 1, wherein the controller is configured to detect the humidity information voltage signal during a transient period, characterized by a change in voltage at the output terminals (13, 14) when powering up or shutting down the LED load (15).
  3. The LED system (10) of claim 2, wherein the controller is further configured to detect the humidity information voltage signal by analyzing a gradient of the voltage ramp-up or ramp-down at its output terminals (13, 14) during the transient period.
  4. The LED system (10) of claim 2 or 3, wherein the humidity sensor (16) is configured to operate during the transient period.
  5. The LED system (10) of claim 4, wherein the humidity sensor (16) comprises: a humistor that changes its impedance based on the humidity and/or temperature inside the LED system, a discrete element that adjusts the current flowing through the sensor based on the impedance change of the humistor, and a passive element that energizes the sensor (16) during the transient period.
  6. The LED system (10) of any preceding claims, wherein the controller is configured to register and store a base level of the voltage ramp in a non-volatile memory as a reference for humidity measurements under predefined environmental conditions.
  7. The LED system (10) of any preceding claims, wherein the controller is further configured to adjust the humidity reading based on ambient temperature, detected using a temperature sensor integrated within the LED driver (11).
  8. The LED system (10) of any preceding claims, wherein the controller is configured to generate an alarm signal if the voltage ramp gradient detected during the transient period exceeds to a predefined threshold indicative of sensor failure or absence.
  9. A LED luminaire comprising: a sealed casing, and a LED system (10) of any of the preceding claims inside said casing.
  10. A method (200) for detecting the humidity level present in the environment of a LED system (10) comprising: a LED driver (11) providing a LED supply voltage (12) at its output terminals (13, 14), a LED load (15) supplied off the output terminals (13, 14) of the LED driver (11), and a humidity sensor (16) having two terminals and being connected in parallel to the LED load (16), the method (200) comprising the step (201) of: reading out a humidity information voltage signal via a voltage present at its output terminals (13, 14).
  11. The method (200) of claim 10, wherein the step (201) of reading out a humidity information voltage signal via a voltage present at its output terminals (13, 14) comprises the step (202) of: detecting the humidity information voltage signal during a transient period, characterized by a change in voltage at the output terminals (13, 14) when powering up or shutting down the LED load (15).
  12. The method (200) of claim 11, wherein the step (202) of detecting the humidity information voltage signal comprises the step of: analyzing a gradient of the voltage ramp-up or ramp-down at its output terminals (13, 14) during the transient period.
  13. The method (200) of any preceding claims, further comprising: registering and storing a base level of the voltage ramp in a non-volatile memory as a reference for humidity measurements under predefined environmental conditions.
  14. The method (200) of any preceding claims, further comprising: adjusting the humidity reading based on ambient temperature, detected using a temperature sensor integrated within the LED driver (11).
  15. An integrated controller for a LED driver (11), arranged to support a method (200) according to any of claims 10 to 14.

Description

TECHNICAL FIELD The present invention relates to LED systems, specifically to LED lighting systems designed for environments where humidity can affect the operation and longevity of the LED luminaires. More particularly, it addresses the need for integrated humidity sensing solutions within outdoor or industrial lighting fixtures, enabling real-time detection and monitoring of internal humidity levels. The invention further pertains to predictive maintenance systems that utilize sensor data to forecast necessary repairs or replacements, ensuring operational efficiency and longevity of the luminaires. BACKGROUND In the current state of the art, luminaires used in outdoor and industrial applications are often classified with high ingress protection ratings, such as IP66, which signifies resistance to dust and water intrusion. These luminaires typically rely on mechanical precision during assembly and proper sealing techniques to maintain their protective characteristics. However, mechanical stress during installation or field operation can damage the housing or seals, leading to water ingress, which can subsequently cause humidity build-up inside the luminaire. Over time, increased humidity can accelerate the aging of sensitive components, such as LED modules, leading to premature failure. State-of-the-art solutions do not offer a reliable means of detecting humidity ingress before significant damage occurs. Conventional methods rely on visual inspection or reactive maintenance, which is performed only after a failure has occurred. This approach leads to increased downtime and unplanned costs. Moreover, standard aging tests, such as the 85°C/85% relative humidity (RH) accelerated aging test, simulate harsh environmental conditions that LED modules might face. However, these tests cannot account for unexpected humidity build-up in situ, which is a common issue resulting from faulty installation, design weaknesses, or damage during use. To date, there are no affordable and effective solutions integrated within the luminaire to monitor real-time humidity levels and trigger preventive maintenance. As a result, many luminaires operate until they fail, without any early indication of the underlying issues caused by moisture ingress. The inability to detect and address humidity-related issues early leads to reduced operational life and efficiency of lighting systems, as well as higher maintenance and replacement costs. SUMMARY In view of the above-discussed limitations, the objective of this invention is to provide a LED lighting system capable of detecting and responding to humidity levels within a sealed luminaire. Such a system offers real-time monitoring of environmental conditions to prevent moisture ingress, which can degrade LED components and reduce their operational lifespan. An additional objective of this invention is to address the lack of integrated, energy-efficient humidity sensing solutions that operate without additional wiring or complex controllers. This system is particularly valuable in outdoor and industrial environments where harsh conditions can lead to luminaire failures, though it is not limited to such applications. 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, a LED system is provided. The system includes a LED driver that provides a supply voltage at its output terminals, a LED load powered by these terminals, and a humidity sensor connected in parallel to the LED load. The LED driver comprises a controller designed for reading out a humidity information voltage signal via a voltage present at its output terminals. The humidity sensor provides a humidity information voltage signal. Advantageously, the humidity sensor operates using the existing LED power wiring, eliminating the need for additional components or external sensors. This design offers a cost-effective and simple method to integrate humidity sensing directly into the LED system. The elimination of extra wiring and controllers reduces complexity and installation costs while ensuring real-time environmental monitoring to prevent premature failure of the luminaire. According to an implementation form of the first aspect of the invention, the controller is configured to detect the humidity information voltage signal during a transient period, characterized by a change in voltage at the output terminals when powering up or shutting down the LED load. This feature improves the energy efficiency of the system, as the sensor only operates during these short periods of voltage change, rather than continuously. By detecting humidity only during the transient period, the system reduces power consumption while still ensuring effective moisture monitoring. According to a further implementation form of the first aspect of the invention, the controller is