KR20100042323A - Led fluorescent lamp - Google Patents

Abstract

PURPOSE: An LED fluorescent lamp is provided to use an existing ballast for a fluorescent lamp without changing wirings by including at least one capacitive element changing an impedance of a ballast for a fluorescent lamp connected through an outer connect pin. CONSTITUTION: An LED array(10) comprises a plurality of LEDs which are serially connected. The LED array comprises an anode side terminal(10a) and a cathode side terminal(10b). At least one capacitive element(C11-C14) is connected between the LED array and an outer connect pin. The capacitive element changes the impedance of an electric ballast connected through the outer connect pin. The electric ballast is a stabilizer with a half bridge mode. The outer connect pin comprises a first or a fourth connection pin(111,112,113,114).

Description

LED fluorescent lamp

The present invention relates to an LED fluorescent lamp, and more particularly to an LED fluorescent lamp that can be used to replace the existing fluorescent lamp.

With the development of technology, the light efficiency of LEDs (Light Emitting Diodes), which have been used only for small power indicators such as indicators in the past, is being improved enough to be used in real life. In addition, unlike other light sources, LED is an environmentally friendly light source that does not contain mercury, and is widely used as a next-generation light source used for a backlight for a mobile phone, a backlight for an LDC TV, a vehicle lamp, and general lighting. Accordingly, incandescent and fluorescent lamps, which have been used as the main light source for lighting for the last 100 years, are beginning to be replaced by LED lamps.

However, in the case of LED lamps, incandescent lamps can be replaced in the case of E26 base compatible lamps, but when replacing fluorescent lamps that are the mainstream of general lighting, the lighting fixtures or a special ballast must be installed separately. . Therefore, there is a difficulty in changing the wiring inside the luminaire, so that the fluorescent LED lamp is not widely used.

Accordingly, an object of the present invention is to provide an LED fluorescent lamp which can be driven using an existing ballast for a fluorescent lamp without changing a separate dedicated ballast or wiring.

LED fluorescent lamp according to the present invention for achieving the above object, an external connection pin, an LED array including a plurality of LEDs connected in series, and connected between the LED array and the external connection pin, the external connection pin It includes at least one capacitive element for changing the impedance of the fluorescent ballast connected through.

In addition, the LED fluorescent lamp according to the present invention for achieving the above object, LED array including a plurality of LEDs connected in series, between the first to fourth connection pins, the first connection pin and one end of the LED array A first capacitor connected, a second capacitor connected between the second connection pin and the one end of the LED array, a third capacitor connected between the third connection pin and the other end of the LED array, and the fourth connection And a fourth capacitor connected between the pin and the other end of the LED array.

According to the present invention, there is provided an LED fluorescent lamp that can be used as is the existing ballast for fluorescent lamps without installing a separate dedicated ballast or changing the wiring inside the luminaire. Therefore, it is possible to use a high-efficiency lighting by replacing the existing fluorescent lamp without special modification.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

The basic circuits of ballasts for electronic fluorescent lamps, which are widely used in general, include a half bridge method, an instant starter method, a soft starter method, and the conventional iron core choke type ballasts, a method using a starter lamp, a rapid starter method, and the like. Is being used. LED fluorescent lamp according to the present invention is configured to be applicable to all of these ballasts for fluorescent lamps. First, the configuration of the LED fluorescent lamp according to the present invention will be described, and next, the operation process when the LED fluorescent lamp according to the present invention is used for various fluorescent ballasts will be described.

1 is a circuit diagram of an LED fluorescent lamp according to a first embodiment of the present invention. Referring to FIG. 1, the LED fluorescent lamp 110 according to the present exemplary embodiment includes the LED array 10 and the capacitors C11, C12, C13, and C14, which are capacitive elements, and first to fourth connections, which are external connection pins. Pins 111, 112, 113, 114. The LED array 10 may be used in a structure in which two or more are connected in parallel, and the same also applies to the LED fluorescent lamp according to another embodiment described below.

The LED array 10 includes a plurality of LEDs connected in series, and includes an anode side terminal 10a and a cathode side terminal 10b. The capacitor C11 is connected between the anode side terminal 10a of the LED array 10 and the first connection pin 111, and the capacitor C12 is connected to the anode side terminal 10a and the second connection pin 112 of the LED array 10. ) Is connected between. The capacitor C13 is connected between the cathode side terminal 10b of the LED array 10 and the third connection pin 113, and the capacitor C14 is connected to the cathode side terminal 10b of the LED array 10 and the fourth connection pin 114. ) Is connected between.

When the capacitors C11 to C14 are connected to a half-bridge type ballast circuit for a fluorescent lamp described later through at least one of the first to fourth connection pins 111, 112, 113, and 114, a series resonant circuit including an inductor and a capacitor The resonance frequency of can be changed. As the resonance frequency changes, the current flowing through the LED fluorescent lamp 110 is reduced by increasing the impedance of the current control inductor in the fluorescent ballast circuit, so that the existing fluorescent ballast can be used without change.

 FIG. 2 is a diagram illustrating a configuration of the LED array shown in FIG. 1. As shown in (a) of FIG. 2, the LED array 10 generally has a configuration in which a plurality of LEDs are connected in series. However, for the protection of series-connected LEDs, as shown in Fig. 2B, Zener diodes Z1 to Zn may be connected in parallel to each LED in reverse direction.

As described above, since a Zener diode is used in parallel with each LED, a current may flow through the D1 through Dn diodes in a positive period of the AC voltage, but a current may flow through the Zener diodes Z1 through Zn in a negative period. The flow of current through the zener diodes Z1 through Zn can be a reactive loss. Therefore, in order to prevent the flow of current through the Zener diodes Z1 to Zn to increase the efficiency, the LED fluorescent lamp according to the present invention can be changed as in the following embodiment.

3 is a circuit diagram of an LED fluorescent lamp according to a second embodiment of the present invention. Referring to FIG. 3, the LED fluorescent lamp 120 according to the present embodiment includes diodes D21 and D22 connected in series to both terminals of the LED array 12 as compared to the LED fluorescent lamp 110 according to the first embodiment. do. Depending on the environment, only one of diodes D21 and D22 may be added. Diodes D21 and D22 allow current only to flow through LED array 12 in the forward direction. Therefore, when a zener diode is connected in parallel in the LED array 12, current flows through the zener diode in a negative period to prevent power loss from occurring.

4 is a circuit diagram of an LED fluorescent lamp according to a third embodiment of the present invention. Referring to FIG. 4, the LED fluorescent lamp 130 according to the present embodiment has diodes D33 to D36 parallel to capacitors C31 to C34 respectively connected to the first to fourth connection pins 131, 132, 133, and 134, respectively. Is added. Such diodes D33 to D36 may be shorted in a capacitor connected in parallel according to the polarity of the voltage input to the first to fourth connection pins 131, 132, 133, and 134 in a ballast for a fluorescent lamp such as a half bridge method described below. Make it operable.

For example, when a positive voltage is applied to the second connection pin 132, the capacitor C32 is shorted by the diode D34, and the capacitor C34 is shorted by the diode D36. In this case, if the external capacitor is connected to the first connection pin 131 and the third connection pin 133, the resonance frequency of the ballast circuit for the fluorescent lamp may be changed by the current flow of the capacitor C31-the external capacitor-capacitor C33. Can be.

5 is a circuit diagram of an LED fluorescent lamp according to a fourth embodiment of the present invention. Diodes D47 to D50 are added to the LED fluorescent lamp 140 according to the present embodiment, so that the LED fluorescent lamp 140 according to the present embodiment is operated regardless of the phase change of the AC voltage in various ballasts for fluorescent lamps.

6 is a circuit diagram of an LED fluorescent lamp according to a fifth embodiment of the present invention. In the LED fluorescent lamp 150 according to the present embodiment to supply the current for the initial trigger drive of the inverter to the capacitors C51 to C54 connected to the first to fourth connection pins 151, 152, 153, and 154, respectively. Resistors R51 to R54 are added in parallel, respectively.

The LED fluorescent lamp of the configuration as described above can be used in connection with the ballast for a conventional fluorescent lamp used without a separate circuit change. For convenience of description, an operation process of various fluorescent ballasts will be described using the LED fluorescent lamp described with reference to FIG. 5 as an example.

FIG. 7 is a diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used for a fluorescent lamp ballast of a half bridge type. The half-bridge fluorescent ballast is composed of a series resonant circuit consisting of an inductor and a capacitor at the switching output point of a half-bridge inverter composed of switching elements, initially turns on the fluorescent lamp with a series resonance voltage across the capacitor, and once the fluorescent lamp is turned on. The stabilization current flowing through the fluorescent lamp is controlled by the inductor of the series resonance circuit.

Referring to FIG. 7, in the electronic ballast, the resonant frequency of the series resonant circuit and the operating frequencies of the switching elements Q61 and Q62 are synchronized by the current transformer T0. The voltage of the DC power supply is referred to as Vs, and the average current Is supplied to the inverter. In this case, the power Ps is as follows.

In this case, if the operating frequency at which the switching elements Q61 and Q62 operate synchronously is expressed as f, the load current is equal to the average current flowing in the DC power supply. Therefore, if Co''C1, Co''C41 to C44, the average current Is is It can be expressed as

Here, if C41, C42, C43, and C44 are set to C2, Ca = C2 * C1 / (C2 + 2C1), and Ro represents the equivalent resistance of the lamp when the lamp is turned on at high frequency.

At this time, the operating frequency f of the inter may be expressed as follows.

In addition, w ₀ can be represented as follows.

Therefore, the current Is from Equations 2 and 5 can be expressed as follows.

Here, Z can be represented as follows.

In the case of Co >> C1 by Equation 3, the basic region of the resonance frequency f is determined by the value of Ca. Therefore, when the LED fluorescent lamp 140 is connected to operate as follows.

When the switching element Q61 is turned ON and the potential at the point (A) becomes Vs, the resonant current flows in the path of the inductors L0-D44-C41-C1-C43-D46-2Co. When switching element Q62 is turned on, the point (A) becomes the ground potential and the current flows in reverse.

Since the LED fluorescent lamp 140 should be symmetrical for versatility, the capacitors C41 to C44 inside the LED fluorescent lamp 140 should be set to C2 because they should not have polarity according to the LED fluorescent lamp 140 connecting pins. -The composite capacitor Ca value in series of C1-C43 can be expressed as follows.

Therefore, in the case of C2 < C1, the value of C can be expressed as C ≒ C2, and the Z value is increased by the following Equations 7 and 8, and the LED fluorescent lamp 140 is increased by that amount. The flowing current is reduced, which makes it possible to control the current. Accordingly, the LED fluorescent lamp according to the present invention can be mounted on a half-bridge type fluorescent ballast without changing the circuit.

 8 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used for an electronic fluorescent ballast of an instant start method. Referring to FIG. 8, the instant start type electronic fluorescent ballast is maintained by Q71 and Q72 of the switching element by the self-oscillation operation of a circuit composed of transformers T1, T2 and capacitor C1. The output of the switching point (A) is shorted to AC and (B) is the midpoint of the series-connected capacitor Co which is 1/2 Vcc DC to the primary winding T2-1 of transformer T2. In this connection, the fluorescent lamp is initially discharged with a high voltage induced in the secondary winding T2-2 of the transformer T2, and once discharged, the stabilizing lamp current is controlled by the capacitor C1 connected in series with the lamp load.

In the case of using a fluorescent ballast of this type, the basic operation is shown. Transformer T2 induces an AC voltage of high frequency to secondary winding T2-2 by self oscillation. +) In the case of potential, in the section where (C)-C1-D43-D41-LED array 14-D42-D45-(D) the current flows, and (C) the point becomes (-) Current flows to point (D)-D48-D41-LED array 14-D42-D47-C1-(C). In addition, a current path may be formed at points (D)-C43-D47-C1-(C) and (D)-D48-C41-C1-(C).

Thus, the current value flowing in the LED array 10 is controlled by 1 / jwC1 of the current control capacitor C1 of the ballast.

9 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used in an electronic fluorescent ballast of a soft starter method. The ballast for electronic fluorescent lamps of this type connects a series resonant circuit composed of an inductor T3 and a capacitor C1 to the switching point (A) of switching elements Q81 and Q82, and connects one or more lamps to both ends of the resonant capacitor C1. The basic operation is similar to the circuit configuration described with reference to FIG. In this method, however, in order to maximize the life of the fluorescent lamp, T3 secondary preheating windings T3-a and T3-b are wound around the resonant transformer, and the fluorescent lamp is generated by the secondary voltage generated in the preheating winding when the lamp is initially turned on. After sufficiently preheating the filament, by applying a high voltage to the lamp, it is to maximize the lamp life by minimizing the oxide scattering of the lamp filament during lighting.

In this case, if the switching frequency of the switching elements Q81 and Q82 is matched with the inductance value L1 of the inductor T3 and the series resonant frequency of the capacitor C1, as shown in FIG. 7, when f is Co''C1, Co is If you ignore, you get

An AC voltage of frequency f is induced across the capacitor C1. In operation, the current flowing through the filament heating winding T3-a coupled to the inductor T3 flows in the path of Ca-D43-C42 at the positive polarity period, and at D44-in the negative period. It flows through the path of C41-Ca. The current flowing in the winding T3-b flows in the path of C43-D45-Cb in the positive period and in the path of Cb-C43-D46 in the negative period, and the value of the capacitor controlling the current is C41, If we put the values C42, C43, and C44 equal to C2,

Since the current Ca >> C2, the current flowing in the windings T3-a, T3-b is determined by C2, which is the value of C41 to C44, and this capacitor value is a very small value of several thousand picoparades or less. Since the voltage induced by T3-a and T3-b is as low as a few volts, the current flowing through the inductors T3-a and T3-b can be almost ignored.

The main current flowing through the LDE fluorescent lamp 100 is that the potential of the point (B) is (B) in the positive period compared to the point (C) (B)-D44-D41-LED array (14)-D42-D46 In the negative period, current flows in the path of the point (C)-D49-D41-LED array 14-D42-D50-(B).

10 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used in a choke type ballast of a starter lamp type.

Referring to FIG. 10, in the positive period of the input voltage, since the starter lamp S 200 is equal to the open state, current flows through the inductors L-D44-D41-LED arrays 10-D42-D46. , The current at this time is controlled by the impedance jwL of the inductor L.

In the negative period, a current flows in the path of the D49-D41-LED array 14-D42-D50-inductor L, and the current flows in the form of a pulse with a frequency of 2f, which is twice the frequency of the input power supply f. Indicates. Therefore, flickering, which may occur when driving the LED fluorescent lamp 140 at a commercial frequency f, may be significantly reduced.

FIG. 11 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used for a fluorescent ballast of an iron core type rapid starter.

Referring to FIG. 11, when the voltage (+) is applied to the (A) side of the choke winding, the voltages applied to the winding n1 and n2 of the choke for preheating the filament of the fluorescent lamp are referred to as the winding n1, respectively. The load is a capacitor C42 because the diode D43 is shorted in the positive period of the power supply, and the capacitor C41 is also seen as the diode D44 is shorted in the negative period of the power supply. Similarly for winding n2, point (B) shows capacitor C44 in the period of positive voltage and capacitor C43 shows the load of Vn2 in period of negative voltage.

LED fluorescent lamps should not have polarity on either side of the socket and should be symmetrical. For this purpose, the values of capacitors C41, C42, C43, and C44 are designed to be the same unless there is a separate purpose. When placed, this capacitor C2 is designed to have a relatively small capacitance value of several thousand pF or less, so at a frequency of 50 to 60 Hz, the impedance capacitance value of 1 / jwC1 of this capacitor is very large so that the current flowing through it is almost negligible. have.

If you see the path of the main current flowing in the LED fluorescent lamp, if you set the input power voltage to Vo,

Vo is equal to or more than the initial discharge start voltage sufficient to induce the initial discharge of the fluorescent lamp. When looking at the current flowing in the LED array 14, the point (A) is based on the point (B) and the point (A) is in the period of the (+) period-D44-D41-LED array 14-D42-D46- Current flows through the path of point (B), and current flows through the path of point (B)-D49-D41-LED array 14-D42-D50-(A) in the minus period.

Also in this case, like the choke ballast of the starter method of FIG. 10, the current flowing through the LED fluorescent lamp 100 has a pulse current form having a frequency of 2f, which is twice the input power frequency f. Therefore, there is an advantage that can significantly reduce the flicker phenomenon when driving the LED fluorescent lamp at f at a commercial frequency of 50/60 Hz.

As described above, the LED fluorescent lamp according to the present invention can be directly mounted and used without changing a circuit in an electronic ballast which is generally used. In addition, the LED fluorescent lamp according to the present invention is not limited to the configuration and method of the embodiments described as described above, the embodiments are all or part of each embodiment so that various modifications can be made It may alternatively be configured in combination.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a circuit diagram of an LED fluorescent lamp according to a first embodiment of the present invention,

2 is a view showing the structure of the LED array of FIG.

3 is a circuit diagram of an LED fluorescent lamp according to a second embodiment of the present invention;

4 is a circuit diagram of an LED fluorescent lamp according to a third embodiment of the present invention;

5 is a circuit diagram of an LED fluorescent lamp according to a fourth embodiment of the present invention;

6 is a circuit diagram of an LED fluorescent lamp according to a fifth embodiment of the present invention;

7 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used in a half-bridge type fluorescent ballast.

8 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used in an electronic fluorescent lamp ballast of an instant starter type;

9 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used in a soft starter type electronic fluorescent ballast.

10 is a view showing a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used in a choke type ballast using a starter lamp, and

11 is a circuit diagram illustrating a circuit configuration when an LED fluorescent lamp according to an embodiment of the present invention is used in a fluorescent ballast of an iron core type starter method.

Explanation of symbols on the main parts of the drawings

10: LED array 110: LED fluorescent lamp

Claims (14)

External connection pins; An LED array comprising a plurality of LEDs connected in series; And And at least one capacitive element connected between the LED array and the external connection pin to change an impedance of an electronic fluorescent ballast connected through the external connection pin. The method of claim 1, The electronic fluorescent ballast is an LED fluorescent lamp, characterized in that the half-bridge type ballast. The method of claim 1, The external connection pins LED fluorescent lamp comprising a first to fourth connection pins. The method of claim 3, The at least one capacitive element, A first capacitor having one end connected to the first connection pin and the other end connected to an anode side terminal of the LED array; A second capacitor having one end connected to the second connection pin and the other end connected to an anode side terminal of the LED array; A third capacitor having one end connected to the third connection pin and the other end connected to a cathode side terminal of the LED array; And One end is connected to the fourth connection pin, and the other end includes a fourth capacitor connected to the cathode side terminal of the LED array. The method of claim 4, wherein A first resistor connected in parallel with the first capacitor; A second resistor connected in parallel with the second capacitor; A third resistor connected in parallel with the third capacitor; And LED fluorescent lamp further comprises at least one of the fourth resistor connected in parallel to the fourth capacitor. The method of claim 4, wherein And an anode connected to the other end of the first capacitor and a cathode connected to the anode-side terminal of the LED array. The method of claim 4, wherein And an anode connected to a cathode side terminal of the LED array and a cathode connected to the other end of the third capacitor. The method according to claim 6 or 7, A third diode having an anode connected to the first connecting pin and a cathode connected to an anode of the first diode; A fourth diode having an anode connected to the second connecting pin and a cathode connected to an anode of the first diode; A fifth diode having a cathode connected to the third connecting pin and an anode connected to the second diode cathode; And The cathode is connected to the fourth connection pin, the anode further comprises at least one of the sixth diode connected to the second diode cathode. The method of claim 1, The LED array is characterized in that a plurality of LED fluorescent lamps are connected in parallel. An LED array comprising a plurality of LEDs connected in series; First to fourth connecting pins; A first capacitor connected between the first connection pin and one end of the LED array; A second capacitor connected between the second connection pin and the one end of the LED array; A third capacitor connected between the third connection pin and the other end of the LED array; And And a fourth capacitor connected between the fourth connection pin and the other end of the LED array. The method of claim 10, A first diode connected between the first connection pin and the LED array to form a one-way current path in the LED array; And And at least one of a second diode connected between the third connection pin and the LED array to form a one-way current path in the LED array. The method of claim 10, A third diode connected in parallel with the first capacitor and having an anode connected to the first connection pin; A fourth diode connected in parallel to the second capacitor and an anode connected to the second connection pin; A fifth diode connected in parallel with the third capacitor and having a cathode connected to the third connecting pin; And And a sixth diode connected in parallel with the fourth capacitor and having a cathode connected to the fourth pin. The method of claim 12, A seventh diode having an anode connected to the anode of the fifth diode and a cathode connected to the first connecting pin; An eighth diode having an anode connected to the third connecting pin and a cathode connected to a cathode of the first diode; A ninth diode having an anode connected to the fourth connecting pin and a cathode connected to a cathode of the second diode; And The anode is connected to the anode of the sixth diode, the cathode further comprises a tenth diode connected to the second connecting pin. The method of claim 10, A first resistor connected in parallel with the first capacitor; A second resistor connected in parallel with the second capacitor; A third resistor connected in parallel with the third capacitor; And LED fluorescent lamp further comprises a fourth resistor connected in parallel to the fourth capacitor.

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