JP2008010458A - Led lighting circuit, and vehicle room lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting circuit which can perform light emission of LEDs (light emitting diodes) in a plurality of modes through simple and inexpensive circuitry. <P>SOLUTION: A diode bridge circuit is constituted by arranging LEDs 11-14 on four sides, respectively, input terminals A1 and A2 of a DC power supply are connected with a pair of opposing joints 21 and 22, respectively, a pair of other joints 23 and 24 are connected to be short-circuited, a first resistor 15 is connected to a first current path IR1 when the DC power supply is applied using the input terminal A1 as a plus terminal and the input terminal A2 as a minus terminal, and a second resistor 16 having a resistance different from that of the first resistor 15 is connected to a second current path IR2 when the DC power supply is applied using the input terminal A2 as a plus terminal and the input terminal A1 as a minus terminal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an LED lighting circuit capable of emitting light from a plurality of modes of LEDs (light emitting diodes), and a vehicle interior lamp including the LED lighting circuit.

  As an LED lighting circuit capable of emitting a plurality of types of LEDs, as shown in FIG. 4, a second LED 1 and 2 that emit light of the first color are arranged opposite to each other and are different from the first color. A bridge circuit is formed by arranging two LEDs 3 and 4 that emit light to face each other, a resistor 5 for current adjustment is connected between the connection points 8 and 9, and the connection point 6 is connected to the power input terminals A 1 and A 2. , 7 to change the direction of the current to be supplied, and control to select the lighting of the first color LEDs 1 and 2 and the lighting of the second color LEDs 3 and 4. In the lighting circuit of FIG. 4, when a current is passed with the power input terminal A1 being the plus side, the power input terminal A1 → the connection point 6 → LED1 → the connection point 8 → the resistor 5 → the connection point 9 → the LED2 → the connection point 7 → When a current flows in the order of the power input terminal A2, the LEDs 1 and 2 of the first color emit light, and when a current is passed with the power input terminal A2 set to the plus side, the power input terminal A2 → the connection point 7 → the LED 4 → The current flows in the order of connection point 8 → resistance 5 → connection point 9 → LED 3 → connection point 6 → power input terminal A1, and the second color LEDs 3 and 4 emit light (see Patent Document 1).

JP-A-6-188457

  By the way, the voltage drop of the LED differs for each color. In the LED lighting circuit of FIG. 4, the voltage drop caused by the two LEDs 1 and 2 of the first color and the voltage caused by the two LEDs 3 and 4 of the second color. Since the drop is usually different, when the same voltage is applied to the power input terminals A1 and A2 by applying the same voltage to the power input terminals A1 and A2 in the LED lighting circuit, the resistance value is adjusted using the current adjusting resistor 5 as a variable resistor. Is required. However, when such a variable resistor is used, the circuit configuration becomes complicated and the manufacturing cost increases.

  This invention is proposed in view of the said subject, Comprising: The LED lighting circuit which can perform light emission of LED (light emitting diode) of multiple aspects with simple and low-cost circuit structure, and a vehicle provided with an LED lighting circuit The purpose is to provide room lights.

  In the LED lighting circuit of the present invention, the LED is arranged on each of the four sides to form a diode bridge circuit, and the first and second input terminals of the DC power source are connected to a pair of connection points facing each other in the diode bridge circuit, The diode bridge circuit is connected in such a manner that the other pair of opposite connection points of the diode bridge circuit are short-circuited, and the first input terminal is plus and the second input terminal is minus and the DC power supply is applied. The first resistor is connected to the first current path, and the first resistor is connected to the second current path of the diode bridge circuit when a DC power supply is applied with the second input terminal being positive and the first input terminal being negative. A second resistor having a resistance value different from that of the second resistor is connected.

Further, the LED lighting circuit of the present invention is different in the emission color or combination of emission colors of the LED connected to the first current path and the combination of emission color or emission color of the LEDs connected to the second current path. The LED is arranged so that the LED emits light in two light emission modes having different emission colors and combinations of emission colors. In addition to the above configuration, for example, LEDs of the same color are arranged and connected to the first current path and the second current path, and the light emission luminance is different by changing the resistance values of the first resistance and the second resistance. Thus, the LED may emit light in two light emission modes having different light emission luminances, and may further emit light in a plurality of light emission modes in which the light emission color, a combination of the light emission colors, and the light emission luminance are appropriately adjusted. Good.
Moreover, the vehicle interior lamp of the present invention is characterized by including the LED lighting circuit of the present invention. For example, LEDs are arranged on four sides to form a diode bridge circuit, and a pair of connection points opposed to each other in the diode bridge circuit. The first and second input terminals of the DC power supply are connected to each other, the other pair of opposing connection points of the diode bridge circuit are connected, the first input terminal is positive, and the second input terminal is negative. A diode when a DC power supply is applied with a first resistor connected to the first current path of the diode bridge circuit when the power is applied, the second input terminal being positive, and the first input terminal being negative. It is assumed that an LED lighting circuit is provided that connects a second resistor having a resistance value different from that of the first resistor to the second current path of the bridge circuit.

  The LED lighting circuit of the present invention can be used for an appropriate illumination lamp such as an indoor lamp other than the vehicle interior lamp. In addition to the configuration of each invention and each embodiment, the invention of the present application is specified by changing these partial configurations to other configurations, or other configurations are added to these configurations. Or those obtained by deleting these partial configurations to the extent that partial effects can be obtained and specifying them as superordinate concepts.

  The LED lighting circuit of the present invention is provided with a first resistor and a second resistor having different resistance values in the first current path and the second current path of the diode bridge circuit in which the LEDs are arranged, thereby adjusting the current. Even if it does not use complicated variable resistance, it is possible to emit light of a plurality of modes of LEDs, and it is possible to emit light of a plurality of modes of LEDs with a simple and low-cost circuit configuration. Therefore, the user can use different light emission modes or enjoy different light emission modes as necessary.

  An illumination lamp having a very high degree of freedom according to the application, such as the color of illumination light, brightness and darkness, color mixture, and irradiation direction, can be obtained. For example, by changing the light emission color or combination of light emission colors of the LEDs connected to the first current path and the light emission color or light emission color combination of the LEDs connected to the second current path, the colors and color combinations can be changed. By realizing two different light emission modes, or by making the LEDs on the four sides of the diode bridge circuit the same color and making the resistance values of the first and second resistors different, two light emission modes having different light emission luminances are obtained. Can be realized. Further, in the state in which the LED illumination lamp is attached, the irradiation direction of the LED that emits light through the first current path is different from the irradiation direction of the LED that emits light through the second current path, and a required region is selectively selected. It can be made to illuminate.

  In addition, since a resistor having a desired resistance value is used as the first and second resistors and LEDs having different forward voltages from different manufacturers can be used as appropriate, the design freedom is high. Further, even when there is a variation in the forward voltage of the LED, it can be easily dealt with by using a resistor having a required resistance value, and the yield of the LED lighting circuit and the LED illumination lamp having the circuit can be improved. Further, since the LED is lit even if the polarity of the voltage applied to the first and second input terminals is reversed, it is possible to obtain an illuminating lamp in which the LED is lit even if the polarity is reversed.

  In addition, by using the vehicle interior light of the present invention, the user can enjoy a plurality of light emission modes having different colors, color combinations, light emission luminances, and the like, and can also be used according to applications. .

  An embodiment of an LED lighting circuit of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the LED lighting circuit of the first embodiment has a diode bridge circuit in which LEDs 11, 12, 13, and 14 are arranged on four sides, respectively, and a pair of opposing connections on the input side of the diode bridge circuit. The points 21 and 22 are respectively connected to the input terminals A1 and A2 of the DC power source, and the other pair of opposing connection points 23 and 24 on the output side are connected to each other and short-circuited. LED 11 is in the direction from connection point 21 to connection point 23, LED 12 is in the direction from connection point 24 to connection point 22, LED 13 is in the direction from connection point 24 to connection point 21, and LED 14 is in the direction from connection point 22. Connection is made with the direction toward 23 as the forward direction. The LEDs 11 and 12 arranged on two opposite sides of the diode bridge circuit are LEDs having the same color, the LEDs 13 and 14 arranged on the other two opposite sides are LEDs having the same color, and the colors of the LEDs 11 and 12 and the LED 13 , 14 are different in color, for example, the LEDs 11 and 12 are white LEDs and the LEDs 13 and 14 are red LEDs.

  Further, a resistor 15 is connected between the connection point 24 and the connection point 22 between the connection point 24 and the anode side of the LED 12, and a line connecting the connection point 24 and the connection point 21 is connected to the line connecting the connection point 24 and the connection point 22. The resistor 16 is connected between the connection point 24 and the anode side of the LED 13. The resistance value of the first resistor 15 and the resistance value of the second resistor 16 are different from each other. When the voltage drop (Vf) due to the LEDs 11 and 12 is larger than the voltage drop (Vf) due to the LEDs 13 and 14, the first resistance 15 When the resistance value of the resistor 15 is smaller than that of the second resistor 16 and the voltage drop (Vf) due to the LEDs 11 and 12 is smaller than the voltage drop (Vf) due to the LEDs 13 and 14, the resistance value of the first resistor 15 is It is made larger than the second resistor 16. As an example, when LEDs 11 and 12 are white LEDs with a voltage drop of 3.4 V, LEDs 13 and 14 are red LEDs with a voltage drop of 2.0 V, the voltage of the DC power supply is 12 V, and a current of 20 mA is passed through each LED 11 to 14, The resistance value of the first resistor 15 is set to 260Ω, and the resistance value of the second resistor 16 is set to 400Ω.

  When a DC power supply is applied to the LED lighting circuit with the input terminal A1 being positive and the input terminal A2 being negative, as shown in FIG. 2A, the LED 11 has a LED 11, a first resistor 15, and an LED 12 on the path. A current flows in the first current path IR1 of the two-dot chain line, and a current flows in the order of the input terminal A1, the connection point 21, the LED 11, the connection point 23, the connection point 24, the resistor 15, the LED 12, the connection point 22, and the input terminal A2. The first color LEDs 11 and 12 emit light. On the other hand, when a DC power source is applied to the LED lighting circuit with the input terminal A2 being positive and the input terminal A1 being negative, the LED 14 and the second resistor 16 are on the path as shown in FIG. , The current flows through the first current path IR2 of the two-dot chain line in the figure having the LED 13, and the input terminal A2 → the connection point 22 → the LED 14 → the connection point 23 → the connection point 24 → the resistor 16 → the LED 13 → the connection point 21 → the input terminal A1. The current flows in this order, and the second color LEDs 13 and 14 emit light.

  In the LED lighting circuit of the first embodiment, the first resistor 15 and the second resistor 16 having different resistance values are provided in the first current path IR1 and the second current path IR2, thereby making it complicated for current adjustment. Even without using a variable resistor, it is possible to perform light emission by the first light emission mode in which the LEDs 11 and 12 emit light in the first color and light emission by the second light emission mode in which the LEDs 13 and 14 emit light in the second color. .

  In the LED lighting circuit according to the first embodiment, the colors of the LEDs 11 and 12 in one opposing arrangement are different from the colors of the LEDs 13 and 14 in the other opposing arrangement, but the LEDs 11 provided on the four sides of the diode bridge circuit. The colors of .about.14 are all the same, and the resistance values of the first resistor 15 and the second resistor 16 are different, for example, the resistance value of the resistor 15 is larger than that of the resistor 16, and the currents flowing in the LEDs 11,12 and the LEDs 13,14. So that the emission luminance of the LEDs 11 and 12 when the current flows through the first current path IR1 is different from the emission luminance of the LEDs 13 and 14 when the current flows through the second current path IR2. In other words, it is possible to obtain light emission in different light emission modes.

  Further, the first color LED 11, the second color LED 12, the third color LED 13, and the fourth color LED 14 are provided on four sides of the diode bridge circuit, and the LEDs 11 and 12 are the first color and The second color set may emit light, and the LEDs 13 and 14 may emit light with the third color and fourth color set. The first to fourth colors are all different colors, for example, only the fourth color is different, or the first color and the fourth color are the same color, the second color and the third color May be the same color, and the first, fourth, second, and third colors may be different from each other, and at least one different color may be included in the first to fourth colors.

  The number of LEDs provided on each side of the diode bridge circuit is appropriate. For example, as in the second embodiment of FIG. 3, two LEDs 17 and 11 are connected to a line connecting the connection point 21 and the connection point 23. The direction from the point 21 to the connection point 23 is connected in the forward direction, the two LEDs 18 and 14 are connected to the line connecting the connection point 22 and the connection point 23, and the direction from the connection point 22 to the connection point 23 is set to the forward direction. May be connected. The colors of the LEDs 17 and 18 are also appropriate. The LED 17 can be the same color as or different from the LED 11, and the LED 18 can be the same color or different from the LED 14.

  Further, the position where the first resistor 15 is connected in the first current path and the position where the second resistor 16 is connected in the second current path are not limited to the first embodiment. Instead of the position where the first resistor 15 of the first embodiment is connected, the first connecting point 21 and the connecting point 23 in FIG. Instead of the configuration for connecting the resistor 15 or the position for connecting the second resistor 16 of the first embodiment, a line connecting the connection point 22 and the connection point 23, between the cathode side of the LED 14 and the connection point 23. For example, the second resistor 16 may be connected to the position.

  Further, it is preferable that the interior lighting for the vehicle is constituted by the LED lighting circuits of the first and second embodiments and the modified examples, and the interior lighting is performed by the respective LEDs 11 to 14 and the like. The terminals A1 and A2 are preferably connected and used.

  The present invention can be used for, for example, a vehicle interior lamp using an LED as a light source.

The circuit diagram which shows the LED lighting circuit of 1st Embodiment. (A) is explanatory drawing explaining the electric current path | route at the time of flowing an electric current by making power supply input terminal A1 into the LED lighting circuit of FIG. 1 positive, and A2 negative, (b) is a power supply input terminal in the LED lighting circuit of FIG. Explanatory drawing explaining the electric current path | route at the time of flowing an electric current by making A1 into minus and A2 into plus. The circuit diagram which shows the LED lighting circuit of 2nd Embodiment. The circuit diagram which shows the conventional LED lighting circuit.

Explanation of symbols

1, 2, 3, 4, 11, 12, 13, 14, 17, 18 LED
5, 15, 16 Resistors 6, 7, 8, 9, 21, 22, 23, 24 Connection points A1, A2 Power input terminals IR1, IR2 Current path

Claims (3)

The LED is arranged on each of the four sides to form a diode bridge circuit, the first and second input terminals of the DC power supply are connected to a pair of connection points facing each other in the diode bridge circuit, and the other diode bridge circuit A pair of opposing connection points are connected so as to be short-circuited, and when the first input terminal is positive and the second input terminal is negative, a DC power supply is applied to the first current path of the diode bridge circuit. The first resistor and the resistance value are connected to the second current path of the diode bridge circuit when the first resistor is connected, the second input terminal is positive, the first input terminal is negative, and a DC power supply is applied. An LED lighting circuit characterized by connecting second resistors having different values. The LEDs are arranged so that the emission color or combination of emission colors of the LEDs connected to the first current path is different from the emission color or combination of emission colors of the LEDs connected to the second current path. The LED lighting circuit according to claim 1, wherein: A vehicle interior light comprising the LED lighting circuit according to claim 1.

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