JP2007193976A - Led lighting control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress manufacturing cost of an LED lighting control device and simplify layout designing of a circuit board. <P>SOLUTION: A display part 5 is made up of at least first and a second LEDs L1, L2 connected in series. A switching circuit 4 is provided with a first transistor Q1 connected to one end of the first LED L1 and between the first LED L1 and the second LED L2, and a second transistor Q2 connected as a driving load of the first transistor Q1 and connected between the first LED L1 and the second LED L2 and to one end of the second LED L2. A single resistive element 6 is connected in series with the display part 5. A control means 1 drives and controls the switching circuit 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an LED lighting control device that turns on / off an LED by turning on / off a transistor.

As a conventional LED lighting control device, there is one that turns on / off an LED by turning on / off a transistor, which is disclosed in Patent Document 1, for example. As shown in FIG. 4, the LED lighting control device A is composed of a control means 1, a switch circuit 2, and a display unit 3, and includes a CPU, a ROM, a RAM, an input / output interface, and the like. First, second, third, and fourth transistors (npn transistors) Q1, Q2, and Q3 provided in the switch circuit 2 by a control signal output from the control means 1 including a microcomputer (hereinafter referred to as a microcomputer). , Q4 are selectively driven, and the first, second, third, and fourth LEDs L1, L2, L3, and L4 of the display unit 3 connected to the transistors Q1, Q2, Q3, and Q4 are selectively made to emit light. Is. In the figure, R1, R2, R3, and R4 are protective resistors connected to the bases of the transistors Q1, Q2, Q3, and Q4 provided in the switch circuit 2, and R5, R6, R7, and R8 are , Current limiting resistors of the LEDs L1, L2, L3, and L4 provided in the display unit 3. Vb is a drive power source for causing the LEDs L1, L2, L3, and L4 to emit light.
JP-A-6-161595

  However, the LED lighting control device A described above requires current limiting resistors R5, R6, R7, and R8 corresponding to the LEDs L1, L2, L3, and L4 in the display unit 3, and has a large number of parts. There is a problem of increasing the cost. In addition, since the LED lighting control device A requires the respective current limiting resistors R5, R6, R7, and R8, in recent years when miniaturization of the device is desired, the mounting layout of the circuit board on which each electronic component described above is mounted. Has a problem that the layout design becomes complicated.

  The present invention has been made in view of the above-described problems, and aims to suppress the manufacturing cost of the LED lighting control device and simplify the layout design of the circuit board.

  In order to solve the above-described problems, the present invention provides an LED lighting control device that turns on / off an LED by turning on / off a transistor, as in the LED lighting control device according to claim 1, and includes at least a first one. , A display unit formed by connecting second LEDs in series, one end of the first LED, a first transistor connected between the first LED and the second LED, and a first A switching circuit including at least a second transistor connected as a driving load of the transistor and connected between the first LED and the second LED and to one end of the second LED; and A single resistor connected in series and a control means for driving and controlling the switch circuit are provided.

  According to another aspect of the present invention, there is provided an LED lighting control device that turns on / off an LED by turning on / off a transistor, as in the LED lighting control device according to claim 2, and includes at least first and second LEDs. A display unit comprising: a switch circuit comprising at least first and second transistors for respectively driving the first LED and the second LED; and a single unit connected in series to the display unit And a control means for driving and controlling the switch circuit.

  Further, as in the LED lighting control device according to claim 3, in the LED lighting control device according to claim 1 or 2, the control means does not simultaneously drive the first and second transistors. It is controlled by.

  According to a fourth aspect of the present invention, in the LED lighting control device according to the first or second aspect of the present invention, the display unit includes an AT indicator that notifies an AT shift position of the vehicle.

  In addition, as described in claim 5, in the LED lighting control device according to claim 1 or 2, the display unit includes a door indicator that notifies an open / closed state of a vehicle door.

  Further, as described in claim 6, in the LED lighting control device according to claim 1 or 2, the control means is configured to drive the first and second transistors in a time-sharing manner. .

  The present invention relates to an LED lighting control device that turns on / off an LED by turning on / off a transistor, and can reduce the manufacturing cost of the LED lighting control device and simplify the layout design of a circuit board.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will be described by taking as an example the case where the present invention is applied to an AT indicator that informs the AT shift position of a vehicle. However, the same reference numerals are used for the same or corresponding parts as in the conventional example, and detailed description thereof is omitted.

  FIG. 1 shows an LED lighting control device B according to an embodiment of the present invention. The LED lighting control device B includes a control means 1, a switch circuit 4, and a display unit 5.

  The control means 1 is composed of a microcomputer and is used for on / off control of a switch circuit 4 to be described later.

  The display unit 5 connects the first, second, third, and fourth LEDs L1, L2, L3, and L4 in series, and connects the anode side of the first LED L1 to the drive power supply Vb, The cathode side of the LED L4 is grounded to a ground level via a resistor 6 serving as a common protective resistance for the LEDs L1, L2, L3, and L4. The resistor 6 is set to 510Ω, for example.

  As shown in FIG. 2, the display unit 5 includes an AT indicator 7 that informs the AT shift position of the vehicle, and includes a parking range “P”, a reverse range “R”, a neutral range “N”, and a drive range “D”. , And LED L1, L2, L3, L4 prepared for illuminating each indicator display section 7a, 7b, 7c, 7d, Emits the same emission color.

  The switch circuit 4 includes first, second, third, and fourth transistors (pnp transistors) Q5, Q6, Q7, and Q8 that turn on / off the LEDs L1, L2, L3, and L4, respectively. The first, second, and third transistors Q5, Q6, and Q7 connect the transistors provided in the subsequent stages as driving loads (in the case of the first transistor Q5, the second transistor Q6 serves as the driving load). ), The fourth transistor Q8 connects the resistor 6 as a driving load.

  The connection state will be specifically described. The first transistor Q5 has an emitter connected to the anode side (one end) of the first LED L1, and a collector connected to the cathode of the first LED L1 and the anode of the second LED L2. To the connection point (between the first LED L1 and the second LED L2). The second transistor Q6 has an emitter connected to a connection point between the cathode of the first LEDL1 and the anode of the second LEDL2, and a collector connected between the cathode of the second LEDL2 and the anode of the third LEDL3. Connect between. The third transistor Q7 has an emitter connected to a connection point between the cathode of the second LEDL2 and the anode of the third LEDL3, and a collector connected between the cathode of the third LEDL3 and the anode of the fourth LEDL3. Connect between. The fourth transistor Q8 has an emitter connected to the connection point between the cathode of the third LEDL3 and the anode of the fourth LEDL4, and a collector connected to the cathode of the fourth LEDL4. The bases of the transistors Q5, Q6, Q7, and Q8 of the switch circuit 4 are connected to the output unit of the control means 1 via protective resistors R1, R2, R3, and R4.

  Since the aforementioned LED lighting control device B uses the display unit 5 as the AT indicator 7, any one of the LEDs L1, L2, L3, L4 corresponding to the indicator display units 7a, 7b, 7c, 7d is used. Only the lights up. Therefore, for example, when the user of the vehicle selects the drive range “D”, the control unit 1 inputs the signal indicating the drive range “D”, so that only the fourth LED L4 is turned on. , The bases of the third transistors Q5, Q6, and Q7 are set to a voltage level of “L” to drive the first, second, and third transistors Q5, Q6, and Q7, and the first, second, and third transistors are driven. By bypassing the drive current I applied to the LEDs L1, L2, and L3 and setting the base of the fourth transistor Q8 to a voltage level of “H”, the drive current I is applied to the fourth LED L4, and the fourth LED L4 Lights up.

In addition, when the vehicle user selects the neutral range “N”, the control means 1 inputs the signal of the neutral range “N”, so that only the third LED L3 is turned on. By setting the bases of the fourth transistors Q5, Q6, and Q8 to a voltage level of “L”, the first, second, and fourth transistors Q5, Q6, and Q8 are driven, and the first, second, and fourth transistors are driven. By bypassing the drive current I applied to the LEDs L1, L2, and L4 and setting the base of the third transistor Q7 to a voltage level of “H”, the drive current I is applied to the third LED L3, and the third LED L3 is Light up. Hereinafter, the same processing is performed when the first and second LEDs L1 and L2 are driven.

  The LED lighting control device B includes a display unit 5 formed by connecting at least the first and second LEDs L1 and L2 in series, one end of the first LED L1, and between the first LED L1 and the second LED L2. The first transistor Q1 to be connected and the second transistor connected as a driving load for the first transistor Q1 and connected between the first LEDL1 and the second LEDL2 and to one end of the second LEDL2 A switching circuit 4 having at least Q2; a single resistor 6 connected in series to the display unit 5; and a control means 1 for driving and controlling the switching circuit 4, and Since the control means 1 is controlled so as not to drive the first and second transistors Q1 and Q2 at the same time, the control means 1 includes LEDs of the same system and does not light up each LED simultaneously. In the drive device for lighting any one LED, it is only necessary to provide a single resistor 6 for protecting the LED, and the number of protective resistors can be reduced as compared with the conventional LED lighting control device A. It becomes possible to reduce the manufacturing cost. In addition, since the number of protective resistors can be reduced, the layout design of the circuit board on which each electronic component is mounted can be simplified.

  Moreover, the effect as the LED lighting control apparatus B mentioned above is large by comprising the display part 5 from the AT indicator 7 which notifies the AT shift position of the vehicle. That is, the AT indicator 7 often has the same display color of the indicator unit corresponding to a plurality of shift ranges, and the indicator unit does not light up at the same time, and the LED lighting control device B has a single system configuration. Even when the resistor 6 is used, the light emission luminance of the LED is not varied.

  FIG. 3 shows another embodiment of the present invention, which is different from the above-described embodiment in that the display unit 3 is composed of a door indicator 8 for notifying an open / closed state of a vehicle door.

  The door indicator 8 notifies the opening / closing state of the vehicle door, and has indicator portions 8a, 8b, 8c, 8d for informing the opening / closing states of the doors on the driver's seat, front passenger seat, right rear seat, and left rear seat. is doing. The door indicator 8 is not a display form in which any one of the indicator display portions is displayed in each of the indicator display portions 8a, 8b, 8c, and 8d, and corresponds to a plurality of indicator display portions as long as the door is open. Each LED needs to be lit.

  Accordingly, when the LED lighting control device B inputs to the control means 1 a signal indicating that the plurality of doors are open, for example, a signal indicating that the doors of the driver seat and the passenger seat are open, By sequentially driving each transistor for driving each corresponding LED for each predetermined period, each LED corresponding to the open door can be turned on alternately.

  In addition, when each LED corresponding to a plurality of doors is turned on, it is generally visually recognized that the plurality of LEDs are always turned on by sequentially driving (time-division driving) each transistor with a cycle of 200 Hz or more. In the LED lighting control device B of the present invention, even if the system configuration uses a single resistor 6, the same effect can be obtained by simultaneously emitting a plurality of LEDs without changing the light emission luminance. Obtainable.

  As a control device for sequentially driving a plurality of LEDs using a single resistor 6, an npn transistor indicated by the switch circuit 2 of the LED lighting control device A shown in FIG. 4 can be used. As a configuration in this case, the present invention relates to an LED lighting control device that turns on / off an LED by turning on / off a transistor, a display unit including at least first and second LEDs, the first LED, and the first LED A switch circuit including at least first and second transistors for driving the two LEDs, a single resistor connected in series to the display unit, and control means for driving and controlling the switch circuit; It is set as the structure provided with these. That is, the circuit configuration of the switch circuit 2 shown in FIG. 4 is the same, and in the circuit configuration of the display unit 3, the current limiting resistors R5 to R8 corresponding to the LEDs L1 to L4 are eliminated, and the LEDs L1 to L4 are simply connected in series. An effect similar to that of the LED lighting control device B shown in FIG. 1 can be obtained by connecting one resistor and connecting the drive power supply Vb to one end of the resistor.

The circuit diagram which shows the LED lighting control apparatus which shows embodiment of this invention. The figure which shows the display part of embodiment same as the above. The figure which shows the display part of other embodiment of this invention. The circuit diagram which shows the conventional LED lighting control apparatus.

Explanation of symbols

B LED lighting control device 1 control means 4 switch circuit R1 to R4 protective resistance Q5 to Q8 1st to 4th transistor 5 display unit L1 to L4 1st to 4th transistor 6 resistor 7 AT indicator 8 door indicator

Claims (6)

An LED lighting control device for turning on / off an LED by turning on / off a transistor,
A display unit formed by connecting at least first and second LEDs in series;
One end of the first LED, a first transistor connected between the first LED and the second LED, and a first LED connected to the first transistor as a driving load of the first transistor A switch circuit comprising at least a second transistor connected between the two LEDs and to one end of the second LED;
A single resistor connected in series to the display unit;
Control means for driving and controlling the switch circuit;
An LED lighting control device comprising: An LED lighting control device for turning on / off an LED by turning on / off a transistor,
A display unit comprising at least first and second LEDs;
A switch circuit including at least first and second transistors for respectively driving the first LED and the second LED;
A single resistor connected in series to the display unit;
Control means for driving and controlling the switch circuit;
An LED lighting control device comprising: 3. The LED lighting control device according to claim 1, wherein the control means controls the first and second transistors so as not to be driven simultaneously. The LED lighting control device according to claim 1, wherein the display unit includes an AT indicator that notifies an AT shift position of the vehicle. The LED lighting control device according to claim 1, wherein the display unit includes a door indicator that notifies an open / closed state of a vehicle door. 3. The LED lighting control device according to claim 1, wherein the control unit drives the first and second transistors in a time-sharing manner. 4.

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