KR20110025098A - Circuit for radiating safely light emitting diode lighting - Google Patents

Abstract

PURPOSE: A circuit is provided to make other serially connected LEDs operate normally by shorting an LED with a defect. CONSTITUTION: One constant current unit(110) includes a constant voltage diode(U1). The constant current unit constantly supplies a current. A short unit(120) is serially connected to the constant current unit and includes a first light emitting diode, a fourth resistor(R4), a fifth resistor(R5), a sixth resistor(R6), and a third transistor(Q3). The anode and cathode of the first light emitting diode is connected to the constant current unit. The emitter of the third transistor is connected to the fifth resistor.

Description

Circuit for emitting LED lights safely {CIRCUIT FOR RADIATING SAFELY LIGHT EMITTING DIODE LIGHTING}

The present invention relates to a circuit for safely emitting an LED light, and more particularly, when a problem occurs in any one of the plurality of LED elements connected in series, by causing the problem LED to operate in series by a short The present invention relates to a circuit for safely emitting an LED light that allows other connected LED devices to operate normally.

In general, in the street lamp or indoor lighting, especially in the light emitting diode (LED) lighting module of the subway, several LEDs are connected in series according to the characteristics of the product, and a plurality of LEDs in series are connected in series according to the purpose of the lighting module. By connecting in parallel, the function of the lighting module desired by the user is achieved.

That is, as shown in FIG. 1, in the conventional LED lighting circuit, the DC voltage output from the power is connected to Vout, and the current is applied through the resistor R1 and the LEDs 1 to 5, thereby providing the LEDs 1 to 5. It will emit light.

At this time, the resistor (R1) serves to limit the current by the voltage applied through Vout, but there is no function to adjust the current itself.

Therefore, the conventional LED lighting module as described above is directly affected by the current change due to the voltage fluctuation, that is, the influence of the surge voltage and transients occurring in the surroundings, any one of LED 1 to LED 5 If is opened, there is a problem that the entire LED 1 ~ LED 5 connected in series does not emit light.

Accordingly, the present invention is to solve the above problems, the object is that when a problem, such as open to any one of a plurality of LED elements connected in series, such that the LED is a problem to operate in a short This provides a circuit that safely emits LED lights that allow other LED devices in series to operate normally.

A circuit for safely emitting a LED light according to a first embodiment of the present invention for achieving the above object, the constant current unit 110 is provided with a constant voltage diode (U1) for supplying a constant current, and the constant current unit A circuit for safely emitting LED lights including a short unit 120 connected in series to the 110, wherein the short unit 120 includes a first light emitting diode in which an anode and a cathode are sequentially connected to the constant current unit 110. (LED 1), a fourth resistor (R4) having one end connected to an anode of the first light emitting diode (LED 1) and the other end connected to an emitter of a second transistor (Q2), and the second transistor (Q2). The collector of the second transistor Q2 connected to one end of the fourth resistor R4 and the fifth resistor R5 connected to one end of the emitter of the first light emitting diode LED 1 and connected to the cathode of the first light emitting diode LED 1. One end is connected to the first A sixth resistor R6 having the other end connected to the base of the second transistor Q2, a base connected to the emitter of the second transistor Q2, and a collector connected to the other end of the sixth resistor R6; And a third transistor Q3 having an emitter connected to the other end of the fifth resistor R5.

On the other hand, a circuit for safely emitting a LED light according to a second embodiment of the present invention for achieving the above object is provided with one constant current unit 110 to supply a constant current with a constant voltage diode (U1), and A circuit for safely emitting LED lights, including an SCR unit 130 connected in series with the constant current unit 110, wherein the SCR unit 130 includes a first node in which an anode and a cathode are sequentially connected to the constant current unit 110. A light emitting diode (LED 1), a twentieth resistor (R20) having one end connected to an anode of the first light emitting diode (LED 1), and one end connected to the other end of the twentieth resistor (R20) and the other end of the first A twenty-first resistor R21 connected to the cathode of the light emitting diode LED 1, a second capacitor C2 having one end and the other end connected in parallel to the twenty-first resistor R21, and one end of the twentieth resistor R20. An anode is connected to the 21st resistor R21 A cathode is connected to the other end and includes a thyristor SCR 1 having a gate connected to a contact between the twentieth resistor R20 and the twenty-first resistor 20.

Preferably, the constant current unit 110 includes a first resistor R1 having one end connected to an output voltage Vout applied from an external power, and a cathode and an anode sequentially formed at the other end of the first resistor R1. A first transistor Q1 connected to a constant voltage diode U1 connected to the other end of the first resistor R1, and a collector connected between the output voltage Vout and the first resistor R1; A first capacitor C1 having one end connected between the first resistor R1 and a cathode of the constant voltage diode U1, a second resistor R2 having one end connected to the other end of the first capacitor C1, and And a third resistor R3 connected to the emitter of the first transistor Q1, wherein the other end of the second resistor R2 is between the emitter and the third resistor R3 and the constant voltage diode U1. )

According to a circuit for safely emitting an LED light according to the present invention, when a problem such as an open of any one of the plurality of light emitting diode (LED) elements connected in series, such as to open, cause the problem LED to operate in short This allows other LED devices in series to operate normally.

Other objects and advantages of the present invention in addition to the above object will be apparent from the detailed description of the embodiments with reference to the accompanying drawings.

1 is a view showing a circuit applied to a conventional LED lighting module.
2 is a view showing a circuit for safely emitting an LED light according to a preferred embodiment of the present invention.

Hereinafter, a circuit for safely emitting an LED light according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

<First Embodiment>

First, a circuit for safely emitting an LED light according to a first embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 2, a circuit for safely emitting an LED light according to a first embodiment of the present invention includes one constant current unit 110 and a plurality of short units 120 connected in series with the constant current unit 110. ).

In detail, the constant current unit 110 includes a first resistor R1 having one end connected to an output voltage Vout applied from an external power, and a cathode and an anode connected to the other end of the first resistor R1 sequentially. A first transistor Q1 having a constant voltage diode U1, a base connected to the other end of the first resistor R1, and a collector connected between the output voltage Vout and the first resistor R1; A first capacitor C1 having one end connected between a first resistor R1 and a cathode of the constant voltage diode U1, a second resistor R2 having one end connected to the other end of the first capacitor C1, and And a third resistor R3 connected to the emitter of the first transistor Q1, wherein the other end of the second resistor R2 is between the emitter and the third resistor R3 and the constant voltage diode U1. Is connected to.

The operation of the constant current unit 110 configured as described above is as follows.

That is, when the output voltage Vout is applied to the constant current unit 110 from an external power, the first transistor Q1 is operated while the first capacitor C1 is charged through the first resistor R1. Current flows from the first transistor Q1 and is applied to the second resistor R2 and the third resistor R3.

At this time, a voltage is generated at both ends of the resistor R3 according to the amount of current flowing from the first transistor Q1, and the generated voltage is applied to the constant voltage diode U1.

The constant voltage diode U1 internally has a reference voltage of 2.5 V, and a change in current occurs in the cathode of the constant voltage diode U1 according to a difference between the reference voltage and the voltage between both ends of the third resistor R3. The amount of current flowing through the base of the transistor Q1 is controlled.

This can be seen through the equation such as IC = IB * HFE, the adjustment of the current of the base adjusts the IC current to flow a constant current according to the value of the third resistor (R3).

The short unit 120 is connected to a first light emitting diode LED 1 in which an anode and a cathode are sequentially connected to an anode of the constant voltage diode U1, and one end is connected to an anode of the first light emitting diode LED 1. And one end of the fourth resistor R4 connected to the emitter of the second transistor Q2 and the other end thereof to the emitter of the second transistor Q2, and the other end of the cathode of the first light emitting diode LED 1. A sixth resistor having one end connected to a fifth resistor R5 connected to the second transistor Q2 connected to one end of the fourth resistor R4 and having a second end connected to a base of the second transistor Q2; A third connected to R6 and an emitter of the second transistor Q2, a collector connected to the other end of the sixth resistor R6, and an emitter connected to the other end of the fifth resistor R5; Transistor Q3.

The operation of the constant current unit 110 and the short unit 120 configured as described above is as follows.

That is, in normal operation, a current flows from the constant current unit 110 to the first light emitting diode D1, and any one of the plurality of first to fifth light emitting diodes LED 1 to LED 5. The constant current flows through the constant voltage diode U1 of the constant current unit 110 even during a short circuit.

However, when one of the first to fifth light emitting diodes LED 1 to 5 is open, the third transistor Q3 is turned on through the fourth resistor R4. At the same time, the second transistor Q2 operates.

At this time, the current flowing through the second transistor Q2 generates a voltage across the fifth resistor R5 to continuously turn on the third transistor Q3, and also operates the second transistor Q2. Is continuously maintained, such that the plurality of light emitting diodes including the first light emitting diode LED 1 operate like a short, thereby allowing other light emitting diodes to operate normally.

Here, the plurality of short units 120 may be connected in series to the constant current unit 110.

&Lt; Embodiment 2 >

The second embodiment has a main configuration in which the short unit 120 applied in the first embodiment is replaced by the SCR unit 130, and the constant current unit 110 applied in the first embodiment is applied as it is. Detailed description thereof will be omitted and the SCR unit 130 will be mainly described.

That is, a circuit for safely emitting an LED light according to the second embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 2, a circuit for safely emitting an LED light according to a second embodiment of the present invention includes a plurality of SCR units 130 connected in series to one constant current unit 110.

The SCR unit 130 includes a first light emitting diode LED 1 in which an anode and a cathode are sequentially connected to an anode of the constant voltage diode U1 of the constant current unit 110, and an anode of the first light emitting diode LED 1. A twenty-second resistor R20 having one end connected to the twenty-first resistor; one end connected to the other end of the twentieth resistor R20; and a twenty-first resistor R21 connected to the cathode of the first light emitting diode LED 1; A second capacitor C2 having one end and the other end connected in parallel to the twenty-first resistor R21, an anode connected to one end of the twentieth resistor R20, and a cathode connected to the other end of the twenty-first resistor R21 The thyristor SCR 1 has a gate connected to the contact point between the twentieth resistor R20 and the twenty-first resistor 20.

That is, the operation of the second embodiment configured as described above is as follows.

That is, in normal operation, a current flows from the constant current unit 110 to the first light emitting diode D1, and any one of the plurality of first to fifth light emitting diodes LED 1 to LED 5. The constant current flows through the constant voltage diode U1 of the constant current unit 110 even during a short circuit.

However, when one of the first to fifth light emitting diodes LED 1 to 5 is open, the second capacitor C2 is charged through the twentieth resistor R20 and the twenty-first resistor R21. At the same time, a voltage divided by the twentieth resistor R20 and the twenty-first resistor R21 is applied to the gate of the thyristor SCR 1, and the voltage operates the thyristor SCR 1, whereby the light emitting diodes Make it behave like a short.

Here, a plurality of SCR units 130 may be connected in series to the constant current unit 110.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

110: constant current unit 120: short unit
130: SCR unit

Claims (3)

A circuit including a constant current unit 110 having a constant voltage diode (U1) for supplying a constant current, and a short unit 120 connected in series to the constant current unit 110, the LED for safely emitting light LED
The short unit 120,
An anode and a cathode are sequentially connected to the constant current unit 110, and one end is connected to an anode of the first light emitting diode LED 1, and the other end of the second transistor Q2 is already connected. A fourth resistor R4 connected to the emitter, a fifth resistor R5 having one end connected to an emitter of the second transistor Q2 and the other end connected to a cathode of the first light emitting diode LED 1, and A sixth resistor R6 having one end connected to a collector of a second transistor Q2 connected to one end of a fourth resistor R4 and the other end connected to a base of the second transistor Q2, and the second transistor Q2. And a third transistor (Q3) having a base connected to the emitter of (), a collector connected to the other end of the sixth resistor (R6), and an emitter connected to the other end of the fifth resistor (R5). A circuit that safely emits LED lights. A circuit including a constant current unit 110 having a constant voltage diode U1 to supply a constant current and an SCR unit 130 connected in series with the constant current unit 110 to safely emit LED lighting,
The SCR unit 130,
A first light emitting diode (LED 1) in which an anode and a cathode are sequentially connected to the constant current unit (110), a twentieth resistor (R20) having one end connected to an anode of the first light emitting diode (LED 1), and the 20th. One end connected to the other end of the resistor R20 and the other end connected to the cathode of the first light emitting diode LED 1 and the first and the other end connected in parallel to the twenty-first resistor R21. An anode is connected to the second capacitor C2 and one end of the twentieth resistor R20, and a cathode is connected to the other end of the twenty-first resistor R21, and the twentieth resistor R20 and the twenty-first resistor 20 are connected to each other. And a thyristor (SCR 1) having a gate connected to a contact therebetween. 3. The method according to claim 1 or 2,
The constant current unit 110,
A first resistor R1 having one end connected to an output voltage Vout applied from an external power source, a constant voltage diode U1 having a cathode and an anode sequentially connected to the other end of the first resistor R1, and the first resistor R1; A base is connected to the other end of the resistor R1 and a collector is connected between the output voltage Vout and the first resistor R1, the first transistor Q1, the first resistor R1, and the constant voltage diode. A first capacitor C1 having one end connected between the cathode of U1, a second resistor R2 having one end connected to the other end of the first capacitor C1, and an emitter of the first transistor Q1. And a third resistor (R3) connected to each other, wherein the other end of the second resistor (R2) is connected between the emitter and the third resistor (R3) and the constant voltage diode (U1). Light emitting circuit.

Images