JPH0822579A - Led lamp for ac current - Google Patents

Abstract

PURPOSE:To provide the compact and low heat developed LED lamp for A.C. current used by the commercially available power supply. CONSTITUTION:The LED lamp for A.C. current connects a LED light emitting body 5 through a rectifier diode 2, transistor 3, and current limit resistance 5 to an A.C. power supply terminal 1. The current flows while the voltage is lower than the A.C. semi-wave decided by bias resistances 7 and 8 of a bias circuit 4 and the LED light emitting body 5 is turned on and off twice by one A.C. semi-wave. The LED lamp is turned on and off twice by one A.C. semi- wave with little fluctuation of the brightness of the LED lamp against the power supply voltage and the fluctuation of frequency. Thus, the flickering of the LED lamp is reduced and the consumption power of the current limit resistance is made low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC LED lamp used as an indicator lamp / illumination switch of a commercial power source.

[0002]

2. Description of the Related Art In principle, an LED (light emitting diode) is a semiconductor driven by direct current. Therefore, conventionally, LED
When a lamp is lit by a commercial power source, it is lit by converting it into a DC voltage suitable for an LED light emitter or by connecting several tens of LEDs in series.

[0003]

In the LED lamp described above, the DC power supply circuit is large in the former case and the LE is in the latter case.
Currently, a large number of D's are required, and neither of them takes advantage of the small size of the LED.

In recent years, due to the higher brightness and improved reliability of LED light emitters, AC LEs that can be used in commercial power sources
The need for D-lamps is increasing.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to reduce the size and generate less heat and to use a commercial power source (AC100).
It is intended to provide an AC LED lamp that can be used for V or 200V, 50 or 60Hz).

[0006]

In order to achieve the above object, an AC LED lamp according to claim 1 is formed by connecting an LED light emitter to an AC power supply terminal via a rectifying diode and a transistor. The transistor is switched on from a voltage close to zero when the voltage of the AC half-liquid obtained by half-wave rectification or full-liquid rectification of the AC power supply to a predetermined voltage, L
When the ED turns on and exceeds a predetermined voltage, the transistor switches off and the LED turns off, and the transistor switches on from the predetermined voltage at the same half-wave voltage drop to a voltage close to zero. However, the LED is turned on and is turned on twice by one AC half-wave, and the AC LED lamp according to claim 2 has a predetermined voltage value according to claim 1 as a bias circuit resistance. It is characterized in that the brightness of the LED lamp can be changed by changing it to an arbitrary value by changing.

[0007]

As shown in FIG. 1, in the AC LED lamp of claim 1, the LED light emitting body 5 is connected to the AC power supply terminal 1 via the rectifying diode 2 and the transistor 3, and the voltage is less than a predetermined voltage of AC half wave. Transistor 3 switches on, LE
A current having a waveform as shown by the diagonal lines in FIG. 2 (for half-wave rectification) flows through D, and the LED is turned on. With this lighting method,
Since the predetermined voltage can be made significantly smaller than the AC peak voltage, the value of the current limiting resistor becomes small and the power consumption thereof can be reduced. In addition, since the predetermined voltage does not change even when the power supply voltage and the frequency change, the fluctuation of the brightness of the LED lamp is small. Further, in the case of half-wave rectification in one cycle of AC, the LED lights up twice, and in the case of full-wave rectification, the LED lights up four times, so that the flicker of the LED lamp is small.

As shown in FIG. 3, the AC LE according to claim 1.
By changing the resistance of the bias circuit 4 of the D lamp, the predetermined voltage changes, so the current flowing through the LED also changes, and the brightness of the LED lamp can be changed.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 4 shows an example of a circuit of the AC LED lamp according to the first aspect.

In FIG. 4, reference numeral 2 is a rectifying diode, 3 is a transistor, and these are connected through a current limiting resistor 6 and an LED light emitter 5 to an AC power supply terminal 1 of a 100 V or 200 V commercial power supply, and a lighting circuit 9 is provided. Make up. Resistance 7
And the resistor 8 form a bias circuit 4 for switching the transistor 3 on and off.

In FIG. 4, the rectifying diode 2 is composed of a bridge of one element for half-wave rectification and four elements for full-wave rectification.

In the circuit of FIG. 4 of the embodiment, the transistor 3 is switched on at a voltage equal to or lower than a predetermined voltage of the AC half-wave of the AC power source, a current flows through the LED light emitter 5, and the LED lamp is turned on.

FIG. 5 is an assembly view of the AC LED lamp shown in FIG.

In FIG. 5, the chip parts are mounted on the printed circuit board 10, but it is also possible to form the hybrid IC or semiconductor IC and the LED chip.

[0016]

According to the first aspect of the invention, the fluctuation of the brightness of the LED lamp is small with respect to the fluctuation of the power supply voltage and the frequency, and since the LED lamp is lit twice with one AC half-wave, the flicker of the LED lamp is prevented. There is an effect that a small-sized AC LED lamp can be obtained with less power consumption due to the current limiting resistance.

The invention according to claim 2 can obtain the effect of the invention according to claim 1, and the LED lamp can be changed by changing the resistance 8 of the bias circuit 4 of FIG. 4 while fixing the resistance 7. The effect is that the brightness of can be changed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an invention according to claim 1.

2 is a diagram showing a waveform of a current flowing through the circuit shown in FIG.

FIG. 3 is a block diagram showing a configuration of the invention described in claim 2.

FIG. 4 is a circuit diagram of an embodiment of the invention described in claim 1.

5 is an assembly view of the embodiment shown in FIG. 4. FIG.

[Explanation of symbols]

 1 AC power supply terminal 2 Rectifier diode 3 Transistor 4 Bias circuit 5 LED light emitter 6 Current limiting resistor 7 Resistor 8 Resistor 9 Lighting circuit 10 Printed circuit board 11 Base and support

Claims (2)

[Claims] 1. An LED light emitter is connected to an AC power supply connection terminal through a rectifying diode, a transistor and a current limiting resistor, and the AC power supply is subjected to half-wave rectification or full-wave rectification at the time of voltage rise of an AC half-wave. When the transistor switches on from a voltage close to zero to a predetermined voltage and the LED lights up, and when the voltage exceeds the predetermined voltage, the transistor switches off and the LED goes off, and when the power supply voltage of the same half-wave falls. From a predetermined voltage to a voltage close to zero, the transistor will switch on and the LED will light up, and it will light up twice with one AC half-wave, producing less heat,
An AC LED lamp characterized in that the fluctuation of the brightness of the LED lamp is small with respect to the fluctuation of the power supply voltage and the fluctuation of the frequency. 2. The LED according to claim 1, wherein the predetermined voltage value is changed to an arbitrary value by changing the resistance of the bias circuit.
AC alternating current, characterized by variable lamp brightness
ED lamp