Driver and lighting module

Abstract

Drivers (100) for a lighting module, comprising: - Driver inputs (P1, P2, P3, P4) for receiving a supply voltage output by an electronic ballast (ECG); - Driver outputs (301, 302) for supplying energy to a light-emitting element; - a bridge (110) for rectifying the supply voltage and providing a rectified voltage; and - a power switching transistor (135) for switching the rectified voltage to supply energy to the driver outputs (301, 302); characterized in that the driver (100) is designed as a driver compatible with intelligent ECGs, wherein an intelligent ECG is a ballast that can operate fluorescent lamps with different wattages, wherein the lower the wattage of the fluorescent lamp, the higher the frequency output of the intelligent ECG, and by - an LC circuit (102, 104) provided via the bridge (110) to stabilize a voltage across the driver outputs (301, 302).

Description

Technical area

[0001] The invention relates to a driver for a lighting module and a lighting module comprising the driver. Technical background

[0002] For years, fluorescent lamps have been widely known and used as an efficient alternative to incandescent bulbs. However, with the advent of LED lamps, even more efficient and longer-lasting light sources are available. Furthermore, the materials used in LED lamps are safer than those used in fluorescent lamps, as they do not contain mercury, for example. Therefore, there is a need to replace existing fluorescent lamps with LED lamps, preferably without having to replace the entire light fixture or lamp socket.

[0003] Currently available fluorescent lamp fixtures often consist of an electronic ballast (also called electronic control gear, or ECG) to regulate and limit the current supplied to the fluorescent lamp. LED lamps (LED retrofit lamps) used as replacements for fluorescent or halogen lamps must therefore be compatible with the ECG.

[0004] Fig. Figure 1 shows a driver for an ECG designed to be compatible with power supplies in various geographical regions, including Europe, the Middle East and Africa (EMEA) and the Asia-Pacific region (APAC). The ECG provides outputs P1, P2, P3, and P4, each connected via filaments 222, 224, 226, and 228 to the [unclear text]. Fig. The ECG is connected to the driver shown in Figure 1. The ECG outputs P1-P4 provide the driver with a high-frequency signal via a relay contactor 230 and a capacitor 240. The energy from the ECG is used to operate a ballast supplied via the driver output terminals 301 and 302. The ECG can be a smart ECG capable of operating various fluorescent tubes such as 28W, 35W, 49W, and 80W. The smart ECG can vary its output current depending on the resistance detected by the filaments 222, 224, 226, and 228. The lower the wattage of the fluorescent lamp, the higher the frequency output of the smart ECG.

[0005] The driver of Fig. Circuit 1 is a passive circuit. It comprises the bridge diodes 112, 114, 116, and 118. These form a bridge connected in parallel to an input filter capacitor 120 and a resistor 132. Another resistor 134, together with a capacitor 138 and a diode 139, controls a gate of a power switching transistor 135. A drain of the power switching transistor 135 is connected via a resistor 136 to a first output terminal 301 of the driver. A source of the power switching transistor 135 is connected via a relay coil 130, which is connected in parallel to a filter capacitor 180, to a second output terminal 302 of the driver.

[0006] The voltage at driver output terminals 301 and 302 depends on the energy supplied by the ECG and the capacitance value of capacitor 240. The capacitance value Z of capacitor 240 varies with the frequency f output by the intelligent ECG according to the equation: Z=12πƒ As a result, the capacitance of capacitor 240 decreases when the frequency output of the intelligent ECG increases. This reduced capacitance, in turn, leads to an increased voltage at the driver output terminals 301 and 302. This voltage can rise to the point where it exceeds a certain voltage range for a lighting element connected via output terminals 301 and 302. Consequently, the power switching transistor 135 may overheat and / or malfunction.

[0007] A solution to this problem has been proposed in the prior art, as described in Fig. Figure 2 shows that this driver includes a comparator 140, which outputs a high voltage to the power switching transistor 135 when the voltage at the driver output terminals 301 and 302 exceeds a predetermined value. The filter capacitor 180 supplies the voltage for the lighting element connected via the output terminals 301 and 302, while a freewheeling diode 185 prevents current from flowing back towards the power switching transistor 135 and the bridge diodes 112, 114, 116, and 118. In summary, the comparator 140 helps to keep the voltage across the relay coil 130 within the specified range.

[0008] German patent application DE 10 2015 216 594 A1 describes an LED lamp device comprising an LED unit, a driver unit for controlling the LED unit, and a resonant unit for providing AC power to the driver unit and for protecting the driver unit and the LED unit. German patent application WO 2017 / 167 643 A1 describes a conversion circuit for converting signals from a ballast into signals for powering a lighting circuit via a rectifier circuit, wherein the lighting circuit includes at least one light-emitting diode. German patent application DE 10 2015 218 836 A1 describes a double-ended LED lamp with a first lamp base and a second lamp base, wherein the LED lamp comprises a driver unit for operation with an electronic ballast and a switching element for galvanic isolation of the LED driver unit. Summary of the invention

[0009] In view of the aforementioned disadvantages of currently available lighting modules, the present invention aims to provide a driver for an LED lamp in order to retrofit an existing lighting module, such as a currently available fluorescent lamp holder with an ECG, and thus make it compatible with an LED lamp.

[0010] The driver is designed to be compatible with intelligent ECGs and improves the stability of the voltage supplied to the LED lamp. This is achieved by automatically adjusting the output voltage based on the frequency of the input voltage.

[0011] The driver can also be less expensive and / or require less complex circuitry than conventional drivers. Furthermore, the driver design can be more compact than that of the state-of-the-art drivers described above, especially when surface-mount devices (SMDs) are used to implement the driver's LC circuitry.

[0012] This problem is solved by a driver for a lighting module according to the independent claim. Preferred embodiments are described in the dependent claims, the description, and the drawings.

[0013] Accordingly, a driver for a lighting module is provided, comprising driver inputs for receiving a supply voltage output by a ballast (ECG) and driver outputs for supplying power to a light-emitting element. A bridge rectifies the supply voltage and provides a rectified voltage; and a power switching transistor switches the rectified voltage to power the driver outputs. The driver is designed to be compatible with intelligent ECGs, where an intelligent ECG is a ballast capable of operating fluorescent lamps of varying wattages, with the lower the wattage of the fluorescent lamp, the higher the frequency output of the intelligent ECG. Furthermore, an LC circuit is provided across the bridge to stabilize the voltage at the driver outputs.

[0014] In a first aspect, a driver is proposed where the bridge comprises a first bridge input and a second bridge input, with the LC circuit connected between the first and second bridge inputs. This allows the LC circuit to at least partially counteract any potential capacitance changes caused by an intelligent ECG.

[0015] Another aspect being considered is the proposal for a passive driver. This design can offer a simpler and more energy-efficient solution for intelligent ECG compatibility.

[0016] Based on one of the aspects mentioned above, the driver can be used to operate an LED lighting module, for example, an LED retrofit tube. The LED retrofit tube can be a T5 or T8 LED retrofit tube.

[0017] A further object of the present invention is to provide a lighting module comprising a driver and a light-emitting element, wherein the light-emitting element is coupled to the driver outputs of the driver. The driver is preferably the driver as described above. That is to say, all features disclosed in connection with the driver are also disclosed in connection with the lighting module and vice versa.

[0018] The light-emitting element preferably comprises a light-emitting diode (LED) or is itself a light-emitting diode. The lighting module can be adapted for installation in an LED lamp. Brief description of the drawings

[0019] The present revelation is more easily understood by reference to the following detailed description in conjunction with the accompanying figures, whereby Fig. 1 a schematic representation of a first type of driver for a lighting module, as known in the prior art, is, Fig. 2 a schematic representation of a second type of driver for a lighting module, as is known in the prior art, Fig. 3. A circuit diagram of an LC circuit is shown. Fig. 4 a diagram of the reaction of the in Fig. The LC circuit shown in section 3 is, Fig. 5 is a schematic representation of an exemplary embodiment of a driver for a lighting module, Fig. 6. A diagram of the voltage at the driver output terminals for the driver of Fig. 1 is, and Fig. 7 a diagram of the voltage at the driver output terminals for the embodiment of the in Fig. The driver shown in section 5 is shown. Detailed description of the invention

[0020] The exemplary embodiment of the driver and the lighting module is explained below with reference to the figures shown. Identical or similar elements, or elements with the same effect, are identified by the same reference numbers, and repeated descriptions may be omitted to avoid redundancy. The numbers and relative sizes of the elements shown in the figures are not to scale. Rather, individual elements may be exaggerated to improve clarity and / or understanding.

[0021] Fig. Figure 3 illustrates an LC resonant circuit with an inductor L102 and a capacitor C104. Such a resonant circuit produces an impedance that varies with the input frequency and is lowest at the resonance point, as shown in Fig. Figure 4 shows that if the input frequency f is higher or lower than the resonance point, the impedance Z of the LC circuit increases.

[0022] In Fig. Figure 5 shows an exemplary embodiment of a driver 100 for a lighting module. In some respects, the driver is similar to the prior art driver in Fig. 1 similar. The driver of Fig. However, 5 differs in that it integrates an LC circuit 102, 104 into its rectifier bridge 110.

[0023] In particular, the rectifier bridge 110 comprises a first bridge input 111 and a second bridge input 113, as well as a first bridge output 115 and a second bridge output 117. The first bridge input 111 is connected to the first bridge output 115 via the bridge diode 112. The second bridge input 113 is connected to the first bridge output 115 via the bridge diode 114. The second bridge output 117 is connected to the first bridge input 111 via the bridge diode 116. The second bridge output 117 is connected to the second bridge input 113 via the bridge diode 118.

[0024] The LC circuit 102, 104 is connected between the first bridge input 111 and the second bridge input 113. The LC circuit 102, 104 allows a portion of the energy received by the intelligent ECG to pass through. By selecting a suitable frequency for the resonant point of the LC circuit 102, 104, the resulting impedance is low when the intelligent ECG generates a frequency around the resonant point. This keeps the voltage at the output terminals 301, 302 relatively stable. In particular, this maintains the output voltage within a specific range, which for some LEDs can be between 5V and 35V. This prevents thermal problems that could damage or destroy the power switching transistor 135.

[0025] The Fig. 6 and Fig. Figure 7 illustrates the difference in output voltage between the driver of Fig. 1 and the driver of Fig. 5. In particular, it shows Fig. 6, that the voltage at the driver output terminals 301, 302 of the driver of Fig. 1 is approximately 65V. Fig. Figure 7 shows that the voltage at the driver output terminals 301, 302 of the driver is Fig. 5 only fluctuates slightly around the value of 18.6V. It follows that the embodiment of Fig. 5 generates an output voltage that remains stable within a certain range.

[0026] It will be obvious to a person skilled in the art that the embodiment shown is only one example among a multitude of possibilities. Therefore, the embodiment discussed here should not be understood as limiting these features and configurations. Any possible combination and configuration of the described features can be chosen according to the scope of the invention. List of reference symbols P1, P2, P3, P4 EC outputs 100 drivers for a lighting module 102 Inductor 104 Capacitor 110 Rectifier bridge 111, 113 First and second bridge entrances 115, 117 First and second bridge exits 112, 114, 116, 118 bridge diodes 120 Input filter capacitor 130 Relay coil 132 resistance 134 Resistance 135 Power switching transistor 136 Resistance 138 Capacitor 139 Diode 140 Comparator 142 Diode 143 Resistance 144 Resistance 145 resistance 146 Resistance 148 Resistance 180 filter capacitor 185 Freewheeling diode 222, 224, 226, 228 filaments 230 Relay contactor 240 filter capacitor 301, 302 First and second driver outputs

Claims

[1] Driver (100) for a lighting module, comprising: - Driver inputs (P1, P2, P3, P4) for receiving a supply voltage output by an electronic ballast (ECG); - Driver outputs (301, 302) for supplying energy to a light-emitting element; - a bridge (110) for rectifying the supply voltage and providing a rectified voltage; and - a power switching transistor (135) for switching the rectified voltage to supply energy to the driver outputs (301, 302); characterized in that the driver (100) is designed as a driver compatible with intelligent ECGs, wherein an intelligent ECG is a ballast that can operate fluorescent lamps with different wattages, wherein the lower the wattage of the fluorescent lamp, the higher the frequency output of the intelligent ECG, and by - an LC circuit (102, 104) provided via the bridge (110) to stabilize a voltage across the driver outputs (301, 302). [2] Driver (100) according to claim 1, wherein the bridge (110) comprises a first bridge input (111) and a second bridge input (113), wherein the LC circuit (102, 104) is connected between the first bridge input (111) and the second bridge input (113). [3] Lighting module comprising a driver (100) according to one of the preceding claims and a light-emitting element, wherein the light-emitting element is coupled to driver outputs (301, 302) of the driver (100).

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