JP2004034742A - Light emitting element driving circuit for vehicular luminaire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving circuit for a vehicular luminaire whereby influence of variation of electric characteristics of a light emitting element block can be restrained and suitable electric current can be supplied to respective light emitting elements of the light emitting element block. <P>SOLUTION: This light emitting element driving circuit 10 having the light emitting element block 18 formed by connecting a plurality of the light emitting elements 14 as an optical source 12 is provided with a direct current power source 11 for supplying driving electric current to the light emitting element block 18, and a connector 13 on which a plurality of connecting ends 20a to 20d, and 21a to 21d showing different electric resistance values. The light emitting element block 18 receives supply from the direct current power source 11 through the connecting ends 20a to 20c and 21a to 21c selected in accordance with the electric characteristics. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving circuit for a vehicle lamp using a light emitting element block formed by connecting light emitting elements such as LEDs (light emitting diode elements) to each other as a light source of the vehicle lamp.
[0002]
[Prior art]
As a light source of a vehicular lamp, there is a light source using an LED that consumes less current. In order to compensate for the shortage of light quantity by each LED, such a light source is configured by a light emitting element block formed by connecting a large number of forward-connected LED strings in parallel so as to be aligned with each other. I have. As the LED for the light emitting element block, an LED exhibiting substantially the same forward voltage characteristic Vf is selected for each block, and each light emitting element block is constituted by the selected LED group.
[0003]
The forward voltage characteristic Vf is represented by a voltage drop value generated in the LED when a constant current is supplied to the LED in the forward direction, that is, a voltage value acting on the LED. Corresponds to the value.
[0004]
When a DC voltage is applied to a light emitting element block composed of a large number of LEDs exhibiting substantially the same electric characteristics Vf, the light emitting element blocks exhibit substantially uniform Vf characteristics, that is, a forward electric resistance value for each block. Since the LEDs are constituted by LEDs, substantially uniform currents flow through the individual LEDs, whereby the LEDs in each light emitting element block emit light with uniform brightness.
[0005]
As described above, by selecting LEDs in the same rank having substantially equal electric characteristics Vf for each light emitting element block, and configuring the light emitting element blocks with these, the variation in brightness of each LED in the light emitting element block is obtained. Is prevented.
[0006]
[Problems to be solved by the invention]
However, if there is a rank difference in the Vf characteristic between the LED groups constituting the light-emitting element block for each light-emitting element block, the Vf characteristic varies among the light-emitting element blocks. For example, a light emitting element block composed of LEDs having a rank of 2.0 to 2.2 V having a Vf characteristic and a light emitting element block composed of LEDs having a rank of 2.2 to 2.4 V have a mean value between them. Then, when a predetermined DC voltage is applied to the light emitting element blocks having the rank difference, a current value flowing through each LED for each light emitting element block depends on the Vf characteristic rank. Therefore, the brightness may be different for each light emitting element block.
[0007]
Further, if there is a rank difference in the Vf characteristics of the light-emitting element blocks, an overcurrent may flow through the LEDs of the light-emitting element blocks having small Vf characteristics. This overcurrent causes deterioration of the LED to be accelerated.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a driving circuit for a vehicular lamp capable of suppressing the influence of variation in electrical characteristics of each light emitting element block and supplying an appropriate current to the light emitting element block.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 is a light emitting element driving circuit for a vehicle lamp using a light emitting element block formed by connecting a plurality of light emitting elements as a light source, and supplying a driving current to the light emitting element block. And a connector provided with a plurality of connection ends connected to the power supply and having different electric resistance values from each other, and the light-emitting element block passes through the connection end selected according to its electric characteristics. It is characterized by receiving power supply.
[0010]
The connector according to claim 2, wherein the connector includes a first connector member provided with the plurality of connection ends connected to the power supply, and a plurality of connection ends connectable to the light emitting element block. A second connector member detachably connected to the first connector member such that the connection end is connectable to the corresponding connection end of the first connector member. The connection ends of the connector member and the power supply are connected by electric paths having mutually different electric resistance values.
[0011]
According to a third aspect of the present invention, the light emitting element block includes a plurality of connection terminals and a plurality of connection terminals, which are aligned in series so as to match the forward direction between the two connection terminals, and are serially connected to each other, and have substantially the same electrical characteristics. A light-emitting element array composed of light-emitting elements, the light-emitting element rows being arranged in parallel with each other between the two connection terminals, and the connection terminals are arranged in accordance with a forward resistance value between the pair of connection terminals. It is selectively connected to the connection end of the first connector member.
[0012]
According to the first and third aspects of the present invention, the connection end to the connector is appropriately set according to the electric characteristics such as the Vf characteristic determined by the forward electric resistance characteristic of each light emitting element constituting the light emitting element block. In this case, an appropriate current can be supplied to each light emitting element regardless of the variation in the electrical characteristics of each light emitting element block.
[0013]
According to the second aspect of the present invention, the connector is composed of the first and second connector members which are detachable from each other, and a large number of light emitting element blocks are connected in advance to the second connection form in each electrical characteristic rank. By connecting to the connector members, the proper connection work between each light emitting element block and the power supply can be performed simply by connecting both connector members, so that the proper connection work between the light emitting element blocks and the power supply can be quickly performed without error. Can be done.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
As shown in FIG. 1, a vehicle lamp drive circuit 10 according to the present invention includes a DC power supply 11, and a connector 13 provided between the DC power supply 11 and a light source 12 that is supplied with power from the DC power supply 11. Is provided.
[0015]
The light source 12 is used as a light source of a lamp such as a rear combination lamp, a tail lamp, or a stop lamp of an automobile. The light source 12 comprises a group of light emitting elements 14 such as a number of light emitting diode elements (LEDs). Each light emitting element 14 has a forward voltage characteristic Vf belonging to one group of, for example, 2.0 to 2.2 V, 2.2 to 2.4 V, or 2.4 to 2.6 V. Between the two connection terminals 15 and 16, the light emitting element rows 17 are connected in series with each other so as to have the same forward direction so that the arrangement directions of the respective anodes and cathodes are the same. The light emitting element blocks 18 are arranged in a matrix by being aligned and connected in parallel so that their forward directions coincide.
[0016]
The light emitting element block 18 composed of a group of light emitting elements 14 having a forward voltage characteristic Vf of, for example, 2.0 to 2.2 V constitutes a first rank light emitting element block 18. Further, the light emitting element block 18 composed of the group of the light emitting elements 14 having the forward voltage characteristic Vf of, for example, 2.2 to 2.4 V constitutes the light emitting element block 18 of the second rank. The light emitting element blocks 18 of the second rank exhibit higher Vf characteristics than the light emitting element blocks 18 of the first rank. Further, the light-emitting element block 18 composed of the group of the light-emitting elements 14 having the forward voltage characteristic Vf of, for example, 2.4 to 2.6 V has a third higher Vf characteristic than the light-emitting element block 18 of the second rank. The light emitting element blocks 18 of the rank are configured.
[0017]
The connector 13 includes a first connector member 20 composed of, for example, a socket connected to the DC power supply 11 via a conductive path 19 provided with a protection resistor R1 and a plug detachably connected to the first connector member 20, for example. And a second connector member 21 made of
[0018]
The socket 20 has first to fourth connection ends 20a to 20d, and the plug 21 has four connection ends 21a to 21d corresponding to the connection ends 20a to 20d of the socket 20, respectively.
[0019]
The fourth connection terminal 20d of the socket 20 is grounded, and the cathode terminal 16 of the light emitting element block 18 is connected to the connection terminal 21d of the plug 21 corresponding to the connection terminal 20d.
[0020]
In the conductive path 19, resistors R1, R2 and R3 interconnected in series are inserted. One end 19a of the conductive path 19 is connected to the DC power supply 11, and the other end is connected to the third connection end 20c. The conductive path 19 is connected to the first connection end 20a between the resistor R1 and the resistor R2 via the branch path 19b. Further, the conductive path 19 is connected to the second connection end 20b between the resistor R2 and the resistor R3 via the branch path 19c.
[0021]
The resistor R1 provided in the conductive path 19 is a protection resistor for preventing an overcurrent from the DC power supply 11 at the time of short circuit, and the protection resistor R1 is provided between the DC power supply 11 and the first connection end 20a. The electric resistance value (R1) is given. An electric resistance value (R1 + R2) of the protection resistor R1 and the resistor R2 connected in series to the protection resistor R1 is provided between the DC power supply 11 and the second connection terminal 20b. The electric resistance value (R1 + R2 + R3) of the protection resistor R1, the resistor R2, and the resistor R3 connected in series is provided between the DC power supply 11 and the third connection terminal 20c.
[0022]
The protection resistor R1 is designed to supply an appropriate current to each light emitting element 14 of the light emitting element block 18 when the third rank light emitting element block 18 having the highest forward voltage characteristic Vf is used. The resistance value is set. The resistor R2 is configured to supply an appropriate current to each light emitting element 14 of the light emitting element block 18 when the second rank light emitting element block 18 having the intermediate forward voltage characteristic Vf is used. The resistance value is set in relation to the resistor R1. Further, when the first rank light emitting element block 18 having the lowest forward voltage characteristic Vf is used, the resistor R3 supplies an appropriate current to each light emitting element 14 of the light emitting element block 18. The resistance value is set in relation to the resistors R1 and R2.
[0023]
In the drive circuit 10 according to the present invention, according to the rank of the forward voltage characteristic Vf of the light emitting element block 18 of the light source 12 to be driven, the second connection side of the anode side connection terminal 15 of the light emitting element block 18 is connected. The connection terminals 21a to 21c of the connector member 21 are selected.
[0024]
When the light emitting element block 18 is the first rank light emitting element block 18, the third connection end 21c is selected as the connection end of the plug 21 for connecting the anode side connection terminal 15, and the light emitting element block of the second rank is selected. In the case of 18, the second connection terminal 21b is selected, and in the case of the third rank light emitting element block 18, the first connection end 21a is selected. The anode-side connection terminal 15 of the light-emitting element block 18 is connected to connection ends 21a to 21c selected according to the rank.
[0025]
On the other hand, the cathode terminal of the light emitting element block 18 is connected to the fourth connection end 21d regardless of the rank.
[0026]
When the second connector member 21 as a plug to which the light emitting element block 18 is connected is connected to the first connector member 20 as a socket, the connection ends 21a to 21c of the plug 21 to which the anode-side connection terminal 15 is connected. Each of the light emitting elements 14 of the light emitting element block 18 receives a drive current from the DC power supply 11 and emits light through the connection ends 20a to 20c of the socket 20 corresponding to the above.
[0027]
At this time, since the connection ends 21a to 21c of the plug 21 are connected in accordance with the rank of the light emitting element block 18, in the case of the first rank, the current is supplied to the light emitting element block 18 via the resistors R1, R2, and R3. In the case of the second rank, current is supplied to the light emitting element block 18 via the resistors R1 and R2, and in the case of the third rank, current is supplied to the light emitting element block 18 via the resistor R1. .
[0028]
Since each resistor is set so that an appropriate drive current is supplied to the light emitting element block 18 according to each rank, the light emitting element block 18 passes through the selected connection ends 21a to 21c. , The appropriate drive current is supplied regardless of the rank of the light emitting element block 18.
[0029]
Therefore, it is possible to prevent a variation in brightness for each rank of the light emitting element blocks 18 used, and it is possible to obtain a substantially uniform light amount. Further, it is possible to prevent an overcurrent from being supplied to each of the light emitting elements 14 of the light emitting element block 18, and to prevent deterioration of each of the light emitting elements 14 due to the supply of the overcurrent.
[0030]
The example of the light-emitting elements 14 arranged in a matrix as the light-emitting element block 18 has been described. However, as the arrangement of the light-emitting elements 14 in the light-emitting element block 18, a single light-emitting element 14 is arranged in parallel instead of each light-emitting element row 17. The connection or the number of the light emitting element rows 17 and the number of the light emitting elements 14 in each row can be appropriately selected.
[0031]
Further, as described along with the embodiment, the first connector member 20 and the second connector member 21 which can be detached from each other are used, and the anode-side connection ends 15 of the large number of light emitting element blocks 18 are previously set to the light emitting element blocks. By connecting to the predetermined connection ends 21a to 21c for each rank of the Vf characteristic of the block 18, the proper connection work between each light emitting element block 18 and the DC power supply 11 can be performed simply by connecting the two connector members 20, 21. Since the connection can be performed, a proper connection operation between the light emitting element block 18 and the DC power supply 11 can be quickly performed without error.
[0032]
Also, for example, the connection ends 20a to 20c of the socket 20 are selected without using the socket 20 and the plug 21 as the connector 13, and the connection end 15 of the light emitting element block 18 is directly connected to the selected connection ends 20a to 20c. be able to.
[0033]
【The invention's effect】
According to the present invention, by selecting the connection end of the connector according to the electrical characteristics of the light emitting element block, an appropriate current can flow through the light emitting element block irrespective of the variation in the electrical properties. Variations in brightness for each light emitting element can be prevented, and a decrease in durability due to supply of an overcurrent to each light emitting element can be prevented.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram schematically showing a drive circuit 10 according to the present invention.
[Explanation of symbols]
Reference Signs List 10 drive circuit 11 power supply 12 light source 13 connector 14 light emitting element 15, 16 pair of connection terminals 18 light emitting element block 19 conductive path 20 first connector member (socket)
21 Second connector member (plug)
20a to 20d, 21a to 21d Connection ends R1, R2, R3 Resistor

Claims (3)

A light emitting element driving circuit for a vehicle lamp using a light emitting element block formed by connecting a plurality of light emitting elements as a light source, comprising: a power supply for supplying a driving current to the light emitting element block; and a power supply connected to the power supply. A connector provided with a plurality of connection ends exhibiting different electric resistance values from each other, wherein the light-emitting element block receives the supply of the power through the connection end selected according to its electrical characteristics. Light emitting element drive circuit for vehicle lighting. The connector includes a first connector member provided with the plurality of connection ends connected to the power supply, and a plurality of connection ends connectable to the light emitting element block, and the connection ends correspond to the first connection member. A second connector member detachably connected to the first connector member so as to be connectable to the connection end of the first connector member, wherein each of the connection ends of the first connector member is The light emitting element drive circuit according to claim 1, wherein the light source drive circuit is connected to the power supply by an electric circuit having a different electric resistance value. The light-emitting element block is a light-emitting element array including a plurality of light-emitting elements having a pair of connection terminals and a plurality of light-emitting elements having substantially the same electrical characteristics, being connected in series so as to match the forward direction between the two connection terminals. A plurality of light emitting element rows aligned in parallel with each other between the two connection terminals, and the connection terminals are connected to the first connector member in accordance with a forward resistance value between the pair of connection terminals. 3. The light emitting element driving circuit according to claim 2, wherein the light emitting element driving circuit is selectively connected to an end.

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