JP3208438U - LED power supply and LED bulb having the LED power supply - Google Patents

Abstract

The present invention provides a power supply for an LED having a simple circuit configuration, reducing the number of parts and reducing the size of the circuit, and suppressing the generation of noise. LED bulbs are provided in a range where there is no problem in practical use. An LED power supply unit incorporated in a base of an LED bulb is input from a commercial power supply and a protection circuit capable of protecting the LED power supply unit and the LED light source from the commercial power supply side toward the LED light source. A rectifying circuit 12 capable of rectifying and converting the alternating current into direct current, a smoothing circuit 13 capable of removing noise of the alternating current component remaining in the rectified direct current, and a constant current holding the input current at a predetermined current value. It consists of a possible constant current circuit 14. The LED power supply unit suppresses noise from the commercial power supply or noise generated during rectification, and outputs a constant current held at a constant current value. To do. [Selection] Figure 1

Description

  The present invention relates to an LED power source for supplying power to a light emitting diode (LED) and an LED bulb having the LED power source.

Conventionally, an incandescent lamp is a warm color light source having a low color temperature, and is known as an illumination device capable of producing a calm and warm atmosphere. For this reason, it is widely used in spaces where emphasis is placed on staying, such as restaurants and cafes such as coffee shops or restaurants, or hotel lobbies with the aim of producing effects. However, since incandescent lamps consume a large amount of power and have a short lifetime, replacement with LED bulbs is rapidly progressing.
In the LED bulb used for this replacement, a light emitting diode (LED) serving as a light source is made to resemble the filament shape of an incandescent lamp, and the emission color is adjusted to a so-called bulb color of the incandescent lamp. .

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By the way, noise is mixed in the commercial AC power source for lighting the incandescent lamp. The noise is mainly caused by voltage drop / rise due to the use of other electrical equipment, or harmonics and high frequencies from the power plant. However, in the case of an incandescent lamp, the noise is not likely to be a problem even if the AC power supply becomes somewhat unstable.
On the other hand, in the case of an electronic device such as an LED, a current for operating the electronic device is several mA, and a voltage of several volts is sufficient. In this case, there is a possibility that noise mixed in the commercial AC power source may have a great influence, which may cause malfunction or damage of the electronic device. Especially when an LED bulb is connected to a socket that used an incandescent lamp, the above-mentioned noise may cause the LED light source to flicker when it is turned on, or the brightness may be flickering without being stable. .

Here, the LED bulb has an AC / DC circuit that converts alternating current into direct current. AC / DC circuits are called a series system in which AC voltage is converted by a power transformer and then rectified to DC, and a system called switching that converts semiconductor elements and voltage by a high-frequency transformer after converting AC to DC. Can be broadly classified. In the case of the series method, an extremely stable output voltage can be obtained, but the conversion efficiency is lower than that of the switching method, and there are problems such as heat generation and enlargement of components. On the other hand, the switching method can increase the conversion efficiency compared to the series method, and the components can be easily reduced in size and weight, but the circuit is complicated and noise is likely to occur.
However, although there is a possibility of generating noise, there is a great merit that the device can be reduced in size and weight, and a switching type AC / DC circuit is built in a base portion of a conventional LED bulb.

  Therefore, the problem to be solved by the present invention is to provide a power supply for LED that has a simple circuit configuration, is reduced in size by reducing the number of parts, and suppresses the generation of noise, and uses the power supply for LED. Thus, it is an object to provide an LED bulb in which flickering at the time of lighting and change in blinking are within a practical range.

The LED power supply according to claim 1 is an LED power supply that supplies a direct current obtained by rectifying and converting an alternating current input from an alternating current power supply to a light emitting diode (LED).
The LED power supply
A rectifier circuit capable of rectifying and converting the alternating current into the direct current;
A smoothing circuit disposed on the output side of the rectifier circuit and removing noise related to the alternating current from the rectified direct current;
A constant current circuit connected in series with the light source along the forward direction of the direct current on the output side of the smoothing circuit, and capable of holding the direct current at a predetermined value;
When the AC is input from the AC power source,
The direct current obtained by rectifying and converting the alternating current is output at a constant value.

  According to a second aspect of the present invention, there is provided the LED power source according to the first aspect, wherein the constant current circuit includes an npn transistor connected in series to the rectifier circuit, and a base and an emitter of the transistor. It has a Zener diode to be connected.

The LED bulb according to claim 3 is an LED bulb in which an LED power supply unit that supplies a direct current obtained by rectifying and converting an alternating current input from an alternating current power source to a light emitting diode (LED) that is a light source is incorporated in the base. ,
The LED power supply unit
A rectifier circuit capable of rectifying and converting the alternating current into the direct current;
A smoothing circuit disposed on the output side of the rectifier circuit and removing noise related to the alternating current from the rectified direct current;
A constant current circuit connected in series with the light source along the forward direction of the direct current on the output side of the smoothing circuit, and capable of holding the direct current at a predetermined value;
When the AC is input from the AC power source,
The direct current obtained by rectifying and converting the alternating current is output from the LED power supply unit at a constant value,
While the illuminance of the light source is kept constant,
The base can be directly connected to a socket that outputs the AC power supply.

  According to a fourth aspect of the present invention, there is provided the LED bulb according to the third aspect of the invention, wherein the constant current circuit includes an npn transistor connected in series to the rectifier circuit, and a connection between the base and emitter of the transistor. It is characterized by having a Zener diode.

  The LED bulb according to claim 5 is the invention according to claim 3, wherein a protection circuit for protecting the LED power supply unit and the light source is provided between the AC power supply and the LED power supply unit. Features.

According to the LED power supply of the present invention, the LED power supply includes a rectifier circuit, a smoothing circuit, and a constant current circuit, and the constant current circuit includes a transistor and a Zener diode. As a result, the circuit relating to the LED power supply can be simply configured, and the number of components can be reduced, thereby easily reducing the size.
Further, a constant current circuit capable of holding and outputting an input DC current value at a predetermined value is connected in series along the forward direction of the DC flow output from the rectifier circuit.
At this time, the direct current held at a constant value can be taken out even if the input direct current is somewhat disturbed due to the characteristics of the constant current circuit. As a result, it is possible to suppress noise originating from the commercial AC power source and noise when rectifying and converting AC.

According to the LED bulb of the present invention, the LED power source provided in the LED bulb is composed of a rectifier circuit, a smoothing circuit, and a constant current circuit, and the constant current circuit includes a transistor and a Zener diode. As a result, the circuit relating to the LED power supply can be simply configured, and the number of components can be reduced, thereby easily reducing the size.
Furthermore, the miniaturized LED power supply unit can be easily built in a limited space in the base part of the LED bulb. As the number of components of the LED power supply unit is reduced, the number of components constituting the LED bulb can also be reduced, and a reduction in the failure rate of the LED bulb and an improvement in durability can be expected.
Further, a constant current circuit capable of holding and outputting an input DC current value at a predetermined value is connected in series along the forward direction of the DC flow output from the rectifier circuit.
At this time, the direct current held at a constant value can be taken out even if the input direct current is somewhat disturbed due to the characteristics of the constant current circuit. As a result, it is possible to suppress noise originating from the commercial AC power source and noise when rectifying and converting AC. For this reason, when the LED bulb is turned on, flickering of the LED light source and changes in blinking can be within a practically acceptable range.

It is a circuit diagram which shows the outline of a structure of the power supply for LED which concerns on a present Example. It is a perspective view which shows the outline of a structure of the LED bulb | ball which has the power supply for LED which concerns on a present Example.

  As shown in FIG. 2, the LED bulb 1 has an LED light source 2 composed of a plurality of LED strips formed in a filament shape, and is formed in a substantially bulb shape by a metal base 3 and a glass globe 4. ing. A substrate is built in the base 3. A circuit constituting the LED power supply unit 10 according to the present invention is formed on the substrate. The support column erected on the substrate supports the LED light source 2. A male screw that can be screwed with a female screw formed on the inner surface of the socket of the commercial power supply 50 is formed on the outer surface of the base 3. When the base 3 is screwed into the socket, the LED bulb 1 is connected to the commercial power source 50, and power is supplied from the commercial power source 50 to the LED power source unit 10 according to the present invention. Then, the LED power supply unit 10 outputs a direct current obtained by rectifying and converting an alternating current input from the commercial power supply 50 to the LED light source 2.

  An LED power source and an LED bulb having the LED power source according to the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a circuit diagram showing an outline of the configuration of an LED power source according to the present embodiment, and FIG. 2 is a perspective view showing an outline of the configuration of an LED bulb having an LED power source.

The LED light bulb 1 shown in FIG. 2 has an LED power supply unit 10 inside a base 3 formed in a cup shape. As shown in FIG. 1, the LED power supply unit 10 includes a protection circuit 11, a rectifier circuit 12, a smoothing circuit 13, and a constant current circuit 14 from the commercial power supply 50 side toward the LED light source 2 side.
Here, the commercial power source 50 is a single-phase 100V AC power source. Moreover, the commercial power source 50 may be provided with a dimmer capable of adjusting the illuminance of the LED bulb 1 by controlling the AC voltage or current at the output end. Thereby, the LED bulb 1 can change the illuminance.

  The protection circuit 11 includes a first resistor 20 and a varistor 21. The first resistor 20 is connected in series with the commercial power supply 50. Thereby, the inrush current from the commercial power supply 50 to the LED power supply unit 10 can be prevented. The varistor 21 is connected to the commercial power supply 50 in parallel. As a result, when the switch of the commercial power supply 50 is opened or closed, or when the LED bulb 1 is fitted into the socket with the volume of the dimmer increased, the high voltage input transiently from the commercial power supply 50 side. The LED power supply unit 10 or the LED light source 2 can be protected from a voltage surge. Thus, by providing the protection circuit 11, the LED power supply unit 10 and the LED light source 2 can be protected from an excessive current or voltage.

The rectifier circuit 12 includes a diode bridge formed by connecting four diodes of a first diode 22, a second diode 23, a third diode 24, and a fourth diode 25 in a predetermined direction. It is formed so as to rectify. Thereby, the rectifier circuit 12 can output a direct current obtained by full-wave rectifying the alternating current. In addition, the noise of the AC component before rectification remains in the rectified direct current. The noise is derived from the commercial power supply 50, for example, high frequency / harmonic mixed from the power plant via the power transmission / distribution network, or noise accompanying voltage drop / voltage increase caused by supplying power to other electrical devices, etc. Pulsating current generated when rectifying, flicker noise, and the like.
The smoothing circuit 13 includes a capacitor 26 and a second resistor 27 connected in parallel. As a result, the noise generated in the rectifier circuit 12 can be removed and the direct current can be smoothed.
The rectifier circuit 12 and the smoothing circuit 13 can form a direct current that flows in the forward direction from the LED power source unit 10 toward the LED light source 2 in the direction of the arrow A shown in the figure.

The constant current circuit 14 includes an npn transistor 28, a Zener diode 29 connecting the base and emitter of the transistor 28, a third resistor 30 arranged on the emitter side of the transistor 28, a collector and a base of the transistor. The fourth resistor 31 is connected to each other, and is configured to output a direct current held at a constant current value determined from a predetermined reference voltage by the Zener diode 29 and a predetermined resistance value of the third resistor 30. ing.
Thereby, the constant current circuit 14 can remove noise that could not be removed by the smoothing circuit 13. That is, the constant current circuit 14 is configured to output a constant direct current that cancels the fluctuation even when the value of the rectified direct current slightly fluctuates. 2 can be lit at a constant illuminance. Since the direct current supplied to the LED light source 2 at the time of lighting does not include noise, the LED light source 2 is expected to flicker due to the noise or an unstable change in the direct current output. Unintentional dimming can be prevented.
The constant current circuit 14 is not limited to a circuit formed by a combination of the above devices, and may be configured using other devices such as a constant current diode, a field effect transistor (FET), or an operational amplifier.

  The LED power supply unit 10 having the above-described configuration is built in the base 3 of the LED bulb 1 shown in FIG. Here, the LED bulb 1 connected to the commercial power supply 50 operates as described below.

  The alternating current input from the commercial power supply 50 to the LED power supply unit 10 is full-wave rectified to direct current by the rectifier circuit 12. The direct current output from the rectifier circuit 12 is smoothed by removing noise of the alternating current component included in the direct current in the smoothing circuit 13, and the current due to fluctuations in the power supply voltage of the commercial power supply 50 and temperature changes in the constant current circuit 14. Variability is suppressed. The constant current circuit 14 outputs a constant current held at a constant value. The LED power supply unit 10 supplies the constant current to the LED light source 2. The LED light source 2 that is lit by the constant current does not become unstable due to flickering or increase or decrease in the amount of light, and can maintain a constant illuminance.

  According to the LED bulb 1 according to the present embodiment, the LED power supply unit 10 of the LED bulb 1 has the constant current circuit 14 connected in series to the LED light source 2. Since the constant current circuit 14 outputs a constant current held at a constant current value, the LED light source 2 that operates at the constant current can be prevented from becoming unstable during lighting.

1 ... LED bulb, 2 ... LED light source, 3 ... base, 4 ... globe,
10 ... LED power supply,
DESCRIPTION OF SYMBOLS 11 ... Protection circuit, 12 ... Rectification circuit, 13 ... Smoothing circuit, 14 ... Constant current circuit,
DESCRIPTION OF SYMBOLS 20 ... 1st resistor, 21 ... Varistor, 22 ... 1st diode, 23 ... 2nd diode, 24 ... 3rd diode, 25 ... 4th diode, 26 ... Capacitor, 27 ... 2nd resistor, 28 ... Transistor, 29 ... Zener diode, 30 ... 3rd resistor, 31 ... 4th resistor,
50: Commercial power supply.

Claims (5)

An LED power source that supplies a direct current obtained by rectifying and converting an alternating current input from an alternating current power source to a light emitting diode (LED),
The LED power supply
A rectifier circuit capable of rectifying and converting the alternating current into the direct current;
A smoothing circuit disposed on the output side of the rectifier circuit and removing noise related to the alternating current from the rectified direct current;
A constant current circuit connected in series with the light source along the forward direction of the direct current on the output side of the smoothing circuit, and capable of holding the direct current at a predetermined value;
When the AC is input from the AC power source,
A power supply for LED, wherein a direct current obtained by rectifying and converting the alternating current is output at a constant value.   2. The LED power supply according to claim 1, wherein the constant current circuit includes an npn-type transistor connected in series to the rectifier circuit, and a Zener diode connecting a base and an emitter of the transistor. . An LED power supply unit that supplies a direct current obtained by rectifying and converting alternating current input from an alternating current power source to a light emitting diode (LED) that is a light source is an LED bulb built in a base,
The LED power supply unit
A rectifier circuit capable of rectifying and converting the alternating current into the direct current;
A smoothing circuit disposed on the output side of the rectifier circuit and removing noise related to the alternating current from the rectified direct current;
A constant current circuit connected in series with the light source along the forward direction of the direct current on the output side of the smoothing circuit, and capable of holding the direct current at a predetermined value;
When the AC is input from the AC power source,
The direct current obtained by rectifying and converting the alternating current is output from the LED power supply unit at a constant value,
While the illuminance of the light source is kept constant,
An LED bulb characterized in that the base can be directly connected to a socket that outputs the AC power supply.   4. The LED bulb according to claim 3, wherein the constant current circuit includes an npn transistor connected in series to the rectifier circuit, and a Zener diode that connects between a base and an emitter of the transistor.   The LED bulb according to claim 3, wherein a protection circuit for protecting the LED power supply unit and the light source is provided between the AC power supply and the LED power supply unit.

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