CN201177243Y - Dimmable LED lighting - Google Patents

Abstract

The dimmable LED lighting provided by the utility model is composed of a light-emitting diode [LED], a power supply circuit and a light-emitting diode driving circuit. In the driving circuit, there is a dimming PWM control circuit with a timer integrated circuit [NE] as the core [ I], the dimming PWM control circuit has a PWM output terminal [3], and a constant current source chip circuit [II] with a voltage input terminal for driving LED to emit light, the voltage input terminal is connected with the PWM output terminal in the dimming PWM control circuit Terminals are connected via a resistor [R3]. The brightness of the LED can be adjusted by inputting PWM at the voltage input terminal of the constant current source chip circuit, and the output of the constant current source chip to the LED is a constant current instead of a pulse. There is no pulse, so that its working stability and life are better.

Description

Dimmable LED lighting

technical field

The utility model relates to a dimmable LED lighting lamp, in particular to a dimmable high-power LED lighting lamp, which belongs to the technical field of lighting.

Background technique

LED lighting is composed of LED (light emitting diode), power supply circuit and light emitting diode driving circuit. When the LED lighting needs to be dimmed, there is a solution to adjust the current through the LED by modulating the pulse width of the working current to change the brightness. As introduced in the Chinese utility model patent ZL200620047055.9 "Pulse Width Energy Saving LED Dimming Desk Lamp", a timer integrated circuit such as NE555 is used to generate adjustable pulse width and then the light-emitting diode is driven to emit light by boosting the voltage to adjust the pulse width. The width size gets the brightness size. However, this kind of pulse current makes the light-emitting diode work, although the pulse frequency is very high so that people's eyesight cannot detect it, but it is harmful to the service life and work stability of the light-emitting diode.

Contents of the invention

In view of the above shortcomings, the utility model aims to provide a dimmable LED lighting lamp which can not only adjust the light but also not directly adjust the pulse width of the current passing through the light emitting diode.

The dimmable LED lighting lamp provided by the utility model is composed of a light-emitting diode, a power supply circuit and a light-emitting diode drive circuit. In the drive circuit, there is a dimming PWM control circuit with a timer integrated circuit as the core. The dimming PWM control circuit has The PWM output terminal, and a constant current source chip circuit with a voltage input terminal for driving the LED to emit light, the voltage input terminal is connected with the PWM output terminal of the dimming PWM control circuit through a resistor.

As we all know, a constant current source chip circuit with a voltage input terminal (ADJ) can output currents of different magnitudes under the influence of its input voltage pulse width, that is, the PWM (pulse width modulation) input at the voltage input terminal of the constant current source chip circuit ) to adjust the brightness of the LED. However, what the constant current source chip outputs to the LED is a constant current rather than a pulse. Therefore, compared with the prior art, the LED of the present invention emits light without pulses, so that its working stability and life are better.

Description of drawings

Accompanying drawing is the schematic circuit diagram of an embodiment of the utility model, among the figure: I-dimming PWM control circuit, II-constant current source chip circuit, C1, C2, C3-capacitor, D1-diode, LED-light-emitting diode, NE-timer integrated circuit (grade NE555, of which: 1-ground terminal, 2-trigger input terminal, 3-PWM output terminal, 4-reset terminal, 5-control voltage terminal, 6-threshold input terminal, 7-discharge terminal , 8-power terminal), R1, R2, R3-resistors, TR-potentiometer, U-power input terminal.

Detailed ways

In this example, the timer integrated circuit NE555 chip is used as the core to design a circuit with adjustable pulse width, that is, the dimming PWM control circuit. In this circuit, pin 1 of the NE555 chip is grounded, pin 2 is connected to pin 6 and then connected to the power supply through resistor R2, potentiometer TR and another resistor R1, and pin 3 outputs a continuously variable pulse width through a load resistor R3. PWM pulse, pin 4 and pin 8 are connected to the power supply, pin 5 is grounded through the oscillating capacitor C3, pin 7 is connected to the rheostat of the potentiometer, there is a clamping diode D1 between pin 7 and pin 6, and the positive pole of the clamping diode points to pin 7 , 6 feet are also grounded through a capacitor C2, and the power input terminal U is pressed to the ground through a capacitor C1 to filter out interference pulses. Among them, resistor R1, potentiometer TR, resistor R2 and capacitor C2 constitute the required time integration circuit, adjust the potentiometer TR to change the ratio of the resistance value between pin 7 and the power supply terminal and pin 6, and the output of pin 3 can be changed The duty cycle of the pulse.

There is a constant current source chip circuit II with the constant current source chip ZXLD1360 as the core, and its voltage input terminal is connected to the PWM output terminal of the dimming PWM control circuit through the load resistor R3. When the constant current source chip circuit obtains pulses with different duty ratios, it can output driving currents with different intensities to the LED, so as to achieve the effect of dimming the LED. The greater the duty cycle, the greater the drive current output by the constant current source chip circuit, and the greater the brightness of the LED.

Claims (1)

1, a kind of Dimmable LED illuminating lamp, constitute with light emitting diode, power circuit and LED driving circuit, having in drive circuit with the timer integrated circuit is the light modulation pwm control circuit of core, the light modulation pwm control circuit has the PWM output, it is characterized in that the constant-current source chip circuit that has voltage input end that has driving LED luminous in addition, this voltage input end is connected through a resistance with PWM output in the light modulation pwm control circuit.

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