CN109915797B

CN109915797B - Electronic driver for LED lighting module and LED lamp

Info

Publication number: CN109915797B
Application number: CN201711307388.XA
Authority: CN
Inventors: 丁实宇; 杨旭生
Original assignee: Ledvance GmbH
Current assignee: Ledvance GmbH
Priority date: 2017-12-11
Filing date: 2017-12-11
Publication date: 2021-11-30
Anticipated expiration: 2037-12-11
Also published as: CN109915797A; DE102018131596B4; DE102018131596A1

Abstract

An electronic driver (100) for a lighting module (300) and a LED lamp are provided, the electronic driver (100) comprising a thermistor (R1) and inputs (201, 202) for connecting the electronic driver (100) to a ballast unit (200), wherein the thermistor (R1) is coupled with the inputs (201, 202) such that at least during a start-up phase (Δ t) of the electronic driver (100) the thermistor (R1) is connected in parallel to the inputs (201, 202) and such that after the start-up phase (Δ t) the thermistor (R1) is disconnected from the inputs (201, 202) if the ballast unit (200) is a conventional control device or an alternating current power source.

Description

Electronic driver for LED lighting module and LED lamp

Technical Field

The invention relates to an electronic driver for an LED lighting module and an LED lamp.

Background

Fluorescent lamps have been a well-known and widely used lighting module for many years as an effective replacement for incandescent bulbs. However, with the advent of LED lamps, more efficient and long-lived lighting devices are available. Therefore, there is a need to replace existing fluorescent lamps with LED lamps.

Currently available fluorescent lamps are typically operated using a ballast unit, such as an electronic control unit (ECG), a conventional control unit (CCG) or an ac power supply. Hereinafter, the "ac power supply" may be specifically an ac main power supply. The ballast unit may be adapted to regulate and limit the current supplied to the fluorescent lamp and to provide a starting voltage (ignition voltage) during a starting process of the fluorescent lamp. The ballast unit is part of a lamp of a fluorescent lamp.

Replacing the ballast units present in existing light fixtures would be labor intensive and thus require a significant amount of expense. Therefore, it is better to operate the LED lamp using the already installed ballast unit. In order to provide a LED lamp compatible with the ballast unit, currently available LED lamps comprise an electronic driver for adapting the voltage and/or current provided by the ballast to the requirements of a lighting module of the LED lamp, the lighting module comprising a light emitting diode. Otherwise, the electronic and/or optoelectronic components of the LED lamp may be damaged or destroyed by the ballast unit due to the high voltage generated during the start-up sequence. Furthermore, since the power consumption of the LED lamp is lower than that of the fluorescent lamp, the ballast unit will operate in an unstable state without the electronic driver.

However, currently available electronic drivers are optimized for either operation with ECG or CCG (or ac power). In view of compatibility issues, it is advantageous to have an electronic driver for connecting the LED lamp to the ECG and to the CCG. Furthermore, compatible LED lamps typically have a double-sided input. At this time, impedance matching may cause compatibility problems.

Disclosure of Invention

In view of the above-mentioned drawbacks of the currently available systems, it is an object of the present invention to provide an improved electronic driver for an LED lighting module. It is a further object to provide an improved LED lamp.

These objects are solved by an electronic driver and an LED lamp according to the independent claims. The dependent claims, the description and the drawings present preferred embodiments.

Accordingly, an electronic driver for a lighting module is provided. The electronic driver comprises a thermistor and an input for connecting the electronic driver to the ballast unit. The thermistor is coupled to the input such that the thermistor is connected in parallel to the input at least during a start-up phase of the electronic driver, and such that after the start-up phase the thermistor is disconnected from the input if, in particular only if, the ballast unit is a conventional control device or an alternating current power supply.

The start-up phase may be an initial phase in which ignition is normally performed if the fluorescent tube is connected to the ballast unit. In case of a conventional control device (CCG) as ballast unit, a high temperature may occur at the input during the start-up phase, resulting in an increase of the resistance of the thermistor, providing a high impedance when the ballast unit is a CCG.

Throughout this application, indefinite articles such as "a" or "an" are to be understood as meaning either the singular or the plural, especially having the meaning "at least one", "one or more", etc., unless this is explicitly excluded, for example by the term "only one".

A thermistor is a temperature dependent resistor. Preferably, the thermistor is a PTC resistor. That is, the resistance of the thermistor is preferably proportional to the temperature of the thermistor.

The ballast unit provides an alternating current and/or an alternating voltage. In particular, the ballast unit may be a current source.

According to at least one embodiment of the electronic driver, the thermistor is connected in series with the relay, wherein the relay is devoid of semiconductor material. Preferably, the thermistor is also free of semiconductor material. The electronic control means (ECG) may be adapted to detect whether a so-called filament corresponding to the impedance is connected to the ECG. If semiconductor materials are used in the circuit, the filament sensing function may fail.

The relay may be a normally closed relay. The relay may be "on" (conductive state, closed) if the thermistor is connected in parallel to the input, and "off" (non-conductive state, open) if the thermistor is disconnected from the input.

According to at least one embodiment of the electronic driver, at least during the start-up phase, the thermistor has a first resistance if the ballast unit is a conventional control device or an alternating current power supply, and a second resistance if the ballast unit is an electronic control device, the first resistance being at least 2 times (in particular, at least 5 times) the second resistance.

According to at least one embodiment, the electronic driver comprises a voltage detection circuit adapted to detect a voltage provided by the ballast unit and to provide the switching signal to the relay. The voltage detection circuit is preferentially connected to the input terminal.

According to at least one embodiment of the electronic driver, the voltage detection circuit comprises a first transistor and a direct current circuit, wherein the direct current circuit is adapted to provide a high direct voltage to the gate of the first transistor when the ballast unit provides a high alternating voltage of high frequency or to provide a low direct voltage to the gate of the first transistor when the ballast unit provides a low alternating voltage or a high alternating voltage of low frequency. Hereinafter, the "high frequency" may be a frequency above 40kHz, which may be provided by an ECG. The "low frequency" may be a frequency below 100Hz, which may be provided by the CCG or ac power source. The first transistor is "on" (conductive state, closed) or "off" (non-conductive state, open) depending on the dc voltage provided by the dc circuit. In order to provide a direct voltage depending on the frequency of the alternating voltage, the direct current circuit may comprise a capacitor.

According to at least one embodiment of the electronic driver, the voltage detection circuit comprises a first transistor and a second transistor, wherein the relay coil is connected to an emitter of the second transistor. The second transistor thus switches the relay. The first transistor and the second transistor may be connected similarly to a schmitt trigger.

According to at least one embodiment of the electronic driver, the direct current circuit comprises a bidirectional rectifying circuit. The dc circuit thus converts the ac voltage provided by the ballast unit into a dc voltage.

According to at least one embodiment, the electronic driver comprises a PWM controller (PWM: pulse width modulation) and a PWM controller power supply, wherein the PWM controller power supply is coupled to the output of the dc circuit such that the PWM controller power supply is switched on at the end of the start-up phase. When the PWM controller is powered on, the thermistors may be disconnected from the respective input terminals. The PWM controller power supply provides power to the PWM controller, which in turn provides power to the lighting module.

According to at least one embodiment of the electronic driver, the output of the PWM controller power supply is coupled to the gate of the second transistor. The PWM controller power supply may thus control the second transistor.

According to at least one embodiment, the electronic driver comprises a rectifier bridge, wherein the thermistors are coupled between the respective input terminals and the rectifier bridge. The filament detector may detect a fault if the rectifier bridge is directly coupled to the ballast unit, since the rectifier bridge may comprise a semiconductor material, in particular a diode.

According to at least one embodiment of the electronic driver, the thermistor (and the relay and the voltage detection circuit, if applicable) are part of a filament circuit, which is coupled to the input, wherein the equivalent resistance of the filament circuit is at most 10k Ω.

Further, an LED lamp for replacing a fluorescent tube is provided. The LED lamp preferably comprises an electronic driver as described above. That is, all features disclosed with reference to the electronic driver are also disclosed for the LED and vice versa.

An LED light package electronic driver, in particular an electronic driver as described herein, and an LED lighting module having at least one light emitting diode. The LED lighting module is connected with the output end of the electronic driver. Preferably, the LED lamp is a retrofit LED lamp for replacing a fluorescent lamp.

Drawings

Preferred embodiments of the present invention will be explained below with reference to the accompanying drawings.

Fig. 1A, 1B, 1C, 2, 3, 4, and 5 illustrate exemplary embodiments of LED lamps and electronic drivers described herein.

Detailed Description

Hereinafter, exemplary embodiments of the electronic driver and the LED lamp described herein will be described with reference to the accompanying drawings. In the several figures, identical or similar elements or elements having the same effect may be indicated by identical reference numerals. A repetitive description of these elements may be omitted to avoid redundancy. The numerical and dimensional relationships of the elements shown in the drawings to each other should not be considered to be drawn to scale. Rather, individual elements may be shown exaggerated in size for better display and/or understanding.

Fig. 1A, 1B and 1C show an LED lamp having a lighting module 300 and a different type of ballast unit 200, respectively. Each LED lamp includes an electronic driver 100 as described herein and may include an additional driver 110. The additional driver 110 may be formed the same as or similar to the electronic driver 100 described herein. However, the additional driver 110 may also be implemented in a different manner. Furthermore, the individual LED lamps may be free of additional drivers 110 (not shown in fig. 1A to 1C).

Each ballast unit 200 is connected to the

input terminals

201, 202 of the electronic driver 100 (and the additional driver 110). Fig. 1A shows a conventional ac power supply as the ballast unit 200. Fig. 1B shows a CCG as the ballast unit 200. Fig. 1C shows an ECG as ballast unit 200.

To achieve compatibility with all types of ballast units 200, the input impedance of the additional driver 110 should preferably be chosen such that it has a low impedance if the ECG is a ballast unit 200 (in particular for allowing filament detection), and a low impedance if the CCG is a ballast unit 200. This can be achieved, for example, by connecting 2 small-impedance resistors in series.

Electronic driver 100 may be more complex because the input voltage to electronic driver 100 may range up to 185V, even up to 265V, in CCG mode and/or ac mode (fig. 1A and 1B). The input impedance should therefore be much higher than the input impedance of the additional driver 110. If ballast unit 200 is an ECG, this impedance imbalance of electronic driver 100 and additional driver 110 may lead to lamp failure during the start-up phase.

Fig. 2 and 3 illustrate an exemplary embodiment of an electronic driver 100 as described herein. Fig. 2 shows the general concept and fig. 3 shows a specific embodiment. The electronic driver 100 comprises

input terminals

201, 202 for connecting the ballast unit 200 to the electronic driver 100. Furthermore, the electronic driver 100 comprises a filament circuit 101, a rectifier bridge 102 with bridge diodes, a PWM controller power supply 103, a PWM controller 104, an inductor L1A, an inductor L1B, an inductor L2A, an inductor L2B and

output terminals

301, 302 for connecting the lighting module 300 to the electronic driver 100.

The

input terminals

201, 202 are connected in parallel with a first capacitor C1 for filtering out high frequency components. The filament circuit 101 includes a thermistor R1 (particularly, a PTC resistor) and a relay K1, and the relay K1 is a normally closed relay and is connected in series with the thermistor R1.

The filament circuit 101 has a direct current circuit 111, and the direct current circuit 111 has a second capacitor C2, a third capacitor C3, a second diode D2, a first resistor R21, and a second resistor R22. The dc circuit 111 generates a dc voltage from the ac voltage provided by the ballast unit 200. The dc circuit 111 is connected to the first transistor Q1 and the second transistor Q2. The filament circuit 101 further includes a first diode D1.

The electronic driver 100 also comprises other electronic components, such as resistors, capacitors and diodes. The electronic driver 100 comprises a fourth diode D4 and a third resistor R3, which are part of the PWM power supply circuit 103. In addition, the third transistor Q3 is coupled to the output terminal of the PWM controller 104. The PWM controller 104 provides a pulse width modulation signal to the gate of the third transistor Q3, and the third transistor Q3 switches the connection of the lighting module 300 and the ballast unit 200 according to the modulation signal.

Before the LED lamp starts, if the ballast unit 200 is an ECG, the thermistor R1 and relay K1 will first provide low impedance for filament detection in the ECG and for starting the ECG. The current detected by the ECG filament detection can be very small, so that the resistance of the thermistor R1 is very low.

During the start-up phase of the LED lamp, if the ballast unit 200 is ECG, the voltage in the voltage detection circuit 111 will rise and provide a high dc voltage signal to the first transistor Q1. The first transistor Q1 is thus "on", which results in the gate of the second transistor Q2 being connected to ground GND and "off". Thus, relay K1 is still closed ("on"). The ECG and lighting module 300 will therefore operate in a standard mode.

If the ballast unit 200 is a CCG and/or an ac power supply, during the start-up phase, first, the thermistor R1 is connected in parallel to the

input terminals

201, 202. The CCG provides a high temperature, resulting in a temperature increase and a sharp increase in resistance of the thermistor R1. The PWM controller power supply 103 is enabled through the third resistor R3 and the fourth diode D4, thereby supplying a voltage to the gate of the second transistor Q2, which causes the second transistor to be "turned on" (closed). Since the low frequency voltage provided by the CCG or the ac power source cannot pass through the second capacitor C2, the first transistor Q1 is turned "off" (open circuit) in the case that the ballast unit 200 is a CCG. Here, the frequency characteristic of the ballast unit 200 can be utilized. The CCG or ac power supply provides an ac voltage with only a small frequency (e.g., 50Hz to 60Hz), while the ECG provides a high frequency voltage, e.g., at least 40 kHz.

When the second transistor Q2 is "on", the coil of the relay K1 is connected to the PWM controller power supply 103, and the relay K1 is "off" (open), thereby disconnecting the thermistor R1 from the

input terminals

201, 202.

Fig. 4 and 5 show the gate voltage V of the first transistor during the start-up phase at in case the ballast unit 200 is CCG (fig. 4) or ECG (fig. 5)_Q1Thermistor voltage drop V_R1And relay coil voltage V_K1。

Referring to fig. 4, prior to start-up of the PWM controller power supply 103, during a start-up phase Δ t of, for example, 161.8ms, the thermistor R1 has a high voltage of, for example, 347V peak voltage (corresponding to about 230V at 50 Hz). The PWM controller power supply 103 is then activated and provides a voltage to the relay K1 coil, thereby opening the relay K1. Thus, the thermistor R1 is removed from the

input terminals

201, 202.

Referring to fig. 5, in the case of an ECG, the first transistor Q1 is turned "on" because the ac voltage provided by the ECG can pass through the second capacitor C2. Therefore, contrary to the case of CCG or ac power supply, the gate of the second transistor Q2 is connected to ground GND and the relay coil voltage V_K1Too low. Thus, the relay K1 remains closed at all times, and the thermistor R1 remains connected in parallel with the

inputs

201, 202. For example, the voltage drop at thermistor R1 in the case of an ECG may be 14.7V.

The present invention is not limited to the description based on the embodiment. Rather, the invention encompasses any novel feature and any combination of features, including in particular any combination of features in the patent claims, even if this feature or this combination itself is not explicitly described in the patent claims or exemplary embodiments.

Claims

1. An electronic driver (100) for a lighting module (300), comprising a thermistor (R1) and an input (201, 202) for connecting the electronic driver (100) to a ballast unit (200),

wherein the thermistor (R1) is coupled with the input (201, 202) such that the thermistor (R1) is connected in parallel to the input (201, 202) at least during a start-up phase (Δ t) of the electronic driver (100) and such that after the start-up phase (Δ t) the thermistor (R1) is disconnected from the input (201, 202) if the ballast unit (200) is a conventional control device or an alternating current power source,

wherein the thermistor (R1) is connected in series with a relay (K1), wherein the relay (K1) is devoid of semiconductor material;

the electronic driver (100) comprises a voltage detection circuit adapted to detect a voltage provided by the ballast unit (200) and to provide a switching signal to the relay (K1); and

the voltage detection circuit comprises a first transistor (Q1) and a direct current circuit (111), wherein the direct current circuit (111) is adapted to provide a high direct current voltage to the gate of the first transistor (Q1) when the ballast unit (200) provides a high alternating current voltage at a high frequency, and/or to provide a low direct current voltage to the gate of the first transistor (Q1) when the ballast unit (200) provides a low alternating current voltage or a high alternating current voltage at a low frequency.

2. The electronic driver (100) of claim 1, wherein the voltage detection circuit comprises a first transistor (Q1) and a second transistor (Q2), wherein the relay (K1) is connected to an emitter of the second transistor (Q2).

3. The electronic driver (100) of claim 1 or 2, wherein the direct current circuit (111) comprises a bidirectional rectifying circuit.

4. Electronic driver (100) according to claim 1 or 2, comprising a PWM controller (104) and a PWM controller power supply (103), wherein the PWM controller power supply (103) is coupled to an output of the direct current circuit (111) such that the PWM controller power supply (103) is switched on at the end of the start-up phase (Δ t).

5. The electronic driver (100) of claim 4, wherein the output of the PWM controller power supply (103) is coupled to a gate of a second transistor (Q2).

6. The electronic driver (100) of claim 1, comprising a rectifier bridge (102), wherein the thermistor (R1) is coupled between the input (201, 202) and the rectifier bridge (102).

7. The electronic driver (100) as claimed in claim 1, wherein the thermistor (R1), and where applicable the relay (K1) and the voltage detection circuit, are part of a filament circuit (101) coupled to the input terminals (201, 202), wherein the equivalent resistance of the filament circuit (101) is at most 10K Ω.

8. LED lamp for replacing a fluorescent tube, comprising an electronic driver (100) according to claim 1 and a LED lighting module (300) with at least one light emitting diode, wherein the LED lighting module (300) is connected with an output of the electronic driver (100).