SE1351369A1 - LED lamp and method in conjunction with a LED lamp with functionality that simulates a light bulb - Google Patents

Abstract

13 Summary An LED lamp (2) comprising an LED set (4), where the LED lamp (2) is configured to receive an operating voltage via an operating voltage input (6). The LED lamp comprises a control unit (8) comprising a time supply part (10) and a status memory (12) for the LED set (4) where information is stored as to whether it works or not; a first switching unit (14) whose switching is controlled by a first switching signal (16) generated by said control unit (8), and a resistance unit (18) having the resistance R, said resistance unit being arranged to be connected in parallel with said LED set (4) by means of said first coupling unit (14). The control unit (8) is configured to detect an operating voltage at the operating voltage input (6) and that the time supply part (10) is configured to store the time t1 at the time when an operating voltage is detected, and to supply the time At shaved Than t1 as long as the operating voltage is present. The control unit (8) is further configured to control the connection of said resistance unit (18) so that the resistance unit is switched on when information in the status memory (12) shows that the LED set (4) works, and remains switched on as long as At

Description

FIELD OF THE INVENTION The present invention relates to an LED lamp and a method in connection with an LED lamp according to the preambles of the independent claims.

More specifically, it refers to a smart LED lamp with functionality that simulates an incandescent lamp in order to thereby be able to maintain the existing diagnostic function for incandescent light.

Background of the Invention The use of light emitting diodes (LEDs) in headlights, brake lights and other lighting in vehicles is becoming more common. The reason is, among other things, that you get an increased service life and reduced power consumption. A number of LEDs, for example up to 20, are often used together and a unit with several LEDs, called an LED set-up, is included in what will be referred to as the LED lamp.

To get an indication of whether a light bulb is working, a test module that generates a short pulse, a test pulse, is often used to diagnose the light bulb, ie. ensure that the light bulb is working. The pulse has a duration that is long enough to pass the resistance night Over the lannpan, but not so long that the filament "teeth". The pulse length can be up to in the order of 120-250 ms. For a working light bulb, the resistance is known, and is relatively low. For a non-functioning incandescent lamp, where, for example, the incandescent wire is completely or partially off, the resistance is higher. By feeding the resistance, the function of the light bulb can thus be tested.

The test pulses are generated by a test module when the light bulb is off, ie. slack, and is often emitted at regular intervals, e.g. in the order of seconds or minutes.

There are systems for testing LED lamps.

For example, WO-2012/171531 relates to a method and system for diagnosing faults in LED lamps in a vehicle, which, among other things, involved determining an impedance spectrum for the luminaire which is then analyzed.

An LED has a high internal resistance compared to a conventional incandescent lamp. If you replace light bulbs with LED lights in a vehicle with a test module intended for light bulbs, it means that the LED lamp, unlike the light bulb, has time to emit light during the short time that a test pulse on the LED lamp.

AU-2006200462 relates to the use of an LED lamp in vehicles with a test function for incandescent lamps, and in particular how to prevent the LED lamp from flashing when a test pulse is emitted.

Furthermore, the test module's diagnosis of the lamp does not work as intended because the relatively high internal resistance exhibited by the LED lamp will be interpreted by the test module as meaning that the LED lamp does not work, which is incorrect.

It is costly and costly to replace existing test nodules adapted for the diagnosis of light bulbs. There is therefore a desire to be able, with the existing test module, to diagnose the function of the LED lantern, ie. ensure that it works as intended.

The object of the present invention is to provide an LED lamp and a method intended to both ensure that the test module does not give an incorrect diagnosis and to ensure that it gives a correct diagnosis.

Summary of the Invention The present invention, defined by the independent claims, enables a solution to one or more of the problems discussed above.

Preferred embodiments are defined by the dependent claims.

In order to maintain the diagnostic function of an LED lamp and preferably also to ensure that the lamp does not light up or flash when the lamp is off, at least one active switch has been arranged in the LED lamp which initially switches on a resistor, corresponding to the resistor in a light bulb, and then switches over to the LED lamp.

According to a variant, the LED lamp has a "learning function", which means that it measures the length of the test pulse and at a pulse longer than this, the LED lamp is switched on instead of the resistance.

In order to also be able to diagnose the LED lamp, feed the current through the LED set-up in the LED lamp and it turns out that these do not work correctly, s6 the resistance is never switched on and the external test module diagnostic function then shows that the LED lamp is out of order.

The function is controlled by a control unit, preferably a small microprocessor, which is integrated in the LED lamp. As the cost for the control unit and other circuits required is legal, it is possible to build all the functionality into the LED lamp without increasing the price too much.

Thus, in addition to the usual benefits of replacing incandescent lamps with LEDs, you also get a maintained, transparent, diagnostic function because an existing test module can be used. According to one embodiment, flashes during the test pulse are eliminated.

Brief Description of the Drawings Figure 1 is a block diagram schematically illustrating embodiments of the LED lamp according to the invention.

Figures 2-4 schematically show the operating voltage and control signals for different operating cases of the LED lamp.

Figure 5 is a flow chart intended to explain the function of the LED lamp.

Figure 6 is a flow chart intended to illustrate a method intended to be used in connection with the LED lamp.

Detailed Description of Preferred Embodiments of the Invention In the following detailed description, the same or similar functions and elements have consistently been given the same reference numerals.

Figure 1 shows an LED lamp 2 comprising an LED set 4, where the LED lamp 2 is configured to receive an operating voltage via an operating voltage input 6. The operating voltage is normally 12 or 24 volts if the LED lamp is arranged in a vehicle. As mentioned above in the background part, a plurality of LEDs are often contained in an LED lamp, and these have been referred to as a LED set 4, one of which may comprise up to twenty or more LEDs. The LED lamp is, for example, arranged on a vehicle, but can of course also be used in other applications.

The LED lamp 2 is connected to a drive voltage source 26, e.g. a battery in, in a connection module 28 via a coupling part 30. The connection module 28 comprises, for example, a suitable base for mounting the LED lamp. These parts are not described in detail because they are known to those skilled in the art of constructions and construction details.

The coupling part 30 connects, depending on control signals (not shown), the LED lamp to the drive voltage source 26. There is also a test module arranged (not shown) which is used for testing the function of a lamp connected to the connection module. In connection with testing, the lamp is connected to the test module for a fixed period of time, ie. a test pulse is delivered to the lamp, and the test module performs a feed to determine if the lamp is working as intended. The resistance of the lamp is often measured and if the resistance deviates from the expected, the test module generates an error signal, for example an error indicator lamp lights up or an error message is emitted.

The LED lamp further comprises a control unit 8 comprising a time supply part and a status memory 12 for the LED set 4 where information is stored as to whether it, or individual LEDs, works or not. The control unit 8 consists, for example, of a microprocessor which is integrated in the LED lamp. It can be arranged in connection with a connection part, for example a socket, on the LED lamp.

The LED lamp also comprises a first switching unit 14, a "switch", the switching on of which is controlled by a first switching signal 16 generated by said control unit 8. The switching unit 14 preferably consists of a transistor or flake other unit with corresponding functionality.

Furthermore, a resistance unit 18 having the resistance R is provided. Preferably, this is a resistor with a resistance R which is of the order of magnitude as the resistance of an incandescent lamp is switched on when the LED lamp is switched on.

The resistance R is preferably less than 20% of a resistance RLED for the LED set-up - the RLED is high and can be in the order of 1-2. The resistance unit 18 is arranged to be connected in parallel with the LED set 4 using the first switching unit 14.

The control unit 8 is configured to detect an operating voltage at the operating voltage input 6 and that the time supply part 10 is configured to store the time t1 at the time when an operating voltage is detected.

As soon as an operating voltage has been detected, the timing part begins to charge the time At raked Than t1 as long as the operating voltage is present.

The control unit 8 is further configured to control the connection of said resistance unit 18 so that the resistance unit is switched on when information in the status memory 12 shows that the LED set 4 works, and remains switched on as long as At Preferably, the LED lamp comprises a second switch-on unit 20 connected in series with the LED set 4, the switch-on of which is controlled by a second switch-on signal 22 generated by the control unit 8. The LED set is switched on when At> tp. The purpose of the second switching unit 20 is to avoid that the LED set emits a flash during the test pulse. The switch-on unit thus ensures that the LED set is switched off during the test pulse and that it is only switched on when it has been established that it was not a test pulse but that the intention was to switch on the LED lamp.

Since the length of test pulses used can vary, it can be advantageous to supply the length of the test pulse in connection with mounting the LED lamp. The supply takes place when the LED lamp is switched on and when it is slack and only needs to be turned on once. A number of test pulses are received and a representative value for the length tp of a test pulse is determined by the timing portion 10 and stored there. Of course, it is also possible to determine and store a value tp in fOrvag. The length of a test pulse has been discussed above and is often in the order of 120-250 ms.

A diagnostic unit 24 is also arranged in the control unit 8. This is configured to determine if the LED set works as intended, and then to update the status memory accordingly. The function was preferably determined by feeding the current through the LED set during operation, i.e. when the LEDs are lit.

Figure 6 shows a simplified flow diagram of a true method with a LED lamp 2. The LED lamp comprises an LED set 4, where the LED lamp 2 is configured to receive an operating voltage via an operating voltage input 6, and where the LED lamp further comprises a control unit. 8 comprising a time supply part 10 and a status memory 12 for the LED set 4 where information is stored as to whether it works or not.

In the LED lamp there is arranged a first switching unit 14 whose connection is controlled by a first switching signal 16 generated by the control unit 8, and a resistance unit 18 having the resistance R, where the resistance unit is arranged to be connected in parallel with the LED set 4 by means of the first switching unit 14. LED The lamp has also been described above with reference to Figure 1 and what is shown has reference to this description.

The method shown in the flow chart of Figure 6 comprises: detecting an operating voltage at the operating voltage input 6; storing the time t1 at the time when an operating voltage is detected, taking the time that is off from t1 as long as the operating voltage is present, controlling the connection of said resistance unit 18 so that the resistance unit is switched on when information in the status memory 12 shows that the LED set 4 works, and remains switched on as long as At The LED lamp also comprises a second switching unit 20 connected in series with said LED set 4, the switching on of which is controlled by a second switching signal 22 generated by the control unit 8 (see figure 1). The method preferably comprises the step of switching on said LED set-up d6 At> tp.

In connection with the description of the LED lamp above, the step of determining the length tp of a test pulse has been described, and that the control unit 8 comprises a diagnostic unit 24 and that the method then comprises the steps of determining whether the LED set works as intended, and updating said status memory accordingly. . These method steps are indicated in Figure 6 by dashed boxes which indicate that the steps are preferably carried out.

A number of different operational cases can occur. These will now be described with reference to the flow diagram in Figure 5 and to Figures 2-4, each of which schematically illustrates whether the respective connection units 14 and 20 are connected and the level of the operating voltage, ie. if operating voltage is present at the operating voltage input 6. In Figures 2-4, the different levels of the switching units have been denoted "0" or "1", where "0" means that the "switch" is open and "1" means that the "switch" is closed, i.e. connected. The operating voltage is denoted by "U".

The control unit 8 detects whether a floating operating voltage is present at the operating voltage input 6. This is represented by the box at the top left in figure 5. When an operating voltage has been detected, the time when the detection took place is saved ("save t1"). Then check if any error on the LED set is stored in the status memory 12. If an error exists, ie. if previous tests with the diagnostic unit 24 have resulted in a fault and this has been stored in the status memory, the resistor unit 18 will not be switched on. This is the situation illustrated in Figure 4. Ie. a test pulse of length tp is detected, but since an error is present, the resistor unit 18 will not be turned on. The test module in the connection module 28 supplies the resistance which will be high, which is the same result as it would be - power if there was a light bulb where the lead wire was damaged or ay. In other words, the test module will give an indication that the LED is not working properly.

If the LED set instead works as intended, "yes" is met, the resistance unit 18 is switched on by closing the "switch" 14.

From this law, two different cases can occur. Either the operating voltage has been applied to the LED lamp to turn on the lamp (illustrated in Figure 2), or a test pulse has been generated, ie. the operating voltage is applied during the time tp (illustrated in figure 3).

As long as At Nar At> tp, i.e. when the time for the duration of the test pulse has elapsed, 18 is switched off and it is checked whether operating voltage is present. If it is still present, the lamp must be switched on and then the switching unit 20 is switched on and thereby the diodes and thus the LED lamp are switched on.

If the operating voltage is no longer present, either a test pulse was received - this is shown in Figure 3 - and then the switching unit 20 should remain open. Or the lamp has been switched off after being toothed and then the switching unit 20 disconnects the LED set 4.

According to a variant, the second coupling unit has been excluded. The functionality will be the same as described above except that the LED set will flash during the test pulse.

The present invention is not limited to the above-described preferred embodiments. Different alternatives, modifications and equivalents can be used. The above embodiments are, therefore, not to be construed as limiting the scope of the invention as defined by the appended claims.

Claims (10)

An LED lamp (2) comprising an LED set (4), wherein the LED lamp (2) is configured to receive an operating voltage via an operating voltage input (6), characterized in that the LED lamp comprises A control unit (8) comprising a time supply part (10) and a status memory (12) for the LED set (4) where information is stored as to whether it works or not, 2. a first switching unit (14) whose switching is controlled by a first switching signal (16) generated by said control unit (8), 3. a resistance unit (18) having the resistance R, said resistance unit being arranged to be connected in parallel with said LED set (4) by means of said first switching unit (14), the control unit (8) being configured to detect an operating voltage at the operating voltage input (6) and that the time supply part (10) is configured to store the time t1 at the time when an operating voltage is detected, and to supply the time At offset from t1 as long as the operating voltage is present, and the control unit (8) further configured to control the connection of said resistance unit (18) so that the resistance unit is switched on when information in the status memory (12) shows that the LED set (4 ) works, and remains connected as long as At The LED lamp according to claim 1, wherein the resistance R is less than 20% of a resistance RLED for said LED set. The LED lamp according to claim 1 or 2, wherein the LED lamp comprises a second switching unit (20) connected in series with said LED set (4), the switching on of which is controlled by a second switching signal (22) generated by said control unit (8), wherein said LED set-up is switched on when At> tp. The LED lamp according to any one of claims 1-3, wherein the time supply part (10) is configured to determine the length tp of a test pulse. 11 The LED lamp according to any one of claims 1-4, wherein the control unit (8) comprises a diagnostic unit (24) configured to determine if the LED set works as intended, and to update said status memory accordingly. A method in connection with an LED lamp (2) comprising an LED set (4), wherein the LED lamp (2) is configured to receive an operating voltage via an operating voltage input (6), and wherein the LED lamp comprises: a control unit (8) comprising a time supply part (10) and a status memory (12) for the LED set (4) where information is stored as to whether it works or not, 1. a first switching unit (14) whose switching is controlled by a first switching signal (16) generated by said control unit (8), a resistance unit (18) having the resistance R, said resistance unit being arranged to be connected in parallel with said LED set (4) by means of said first switching unit (14), characterized in that the method comprises: detecting an operating voltage at the operating voltage input (6); - storing the time t1 at the time when an operating voltage is detected, 3. feeding the time At raked from t1 as long as the operating voltage is present, 4. controlling the connection of said resistance unit (18) so that the resistance unit is switched on cla information in the status memory (12) shows that the LED set (4) works, and remains connected as long as At The method of claim 6, wherein the resistance R is less than 20% of a resistance RLED for said LED set. The method according to claim 6 or 7, wherein the LED lamp comprises a second switching unit (20) connected in series with said LED set (4), the switching on of which is controlled by a second switching signal (22) generated by said 12 control unit (8), the method comprises the step of switching on said LED set when At> tp. The method of any of claims 6-8, wherein the method comprises the step of determining the length tp of a test pulse. The method according to any of claims 6-9, wherein the control unit (8) comprises a diagnostic unit (24) and that the method comprises the steps of determining whether the LED set works as intended, and updating said status memory accordingly. 1/2 18 14 8 12 - \ 16 '22 24