CN210868248U

CN210868248U - LED light sense adjusting constant current circuit based on NE555 chip

Info

Publication number: CN210868248U
Application number: CN201921476044.6U
Authority: CN
Inventors: 张叶茂; 梁林德; 莫淑贤; 王永宁; 刘红艳; 陈新菡
Original assignee: Nanning College for Vocational Technology
Current assignee: Nanning College for Vocational Technology
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2020-06-26
Anticipated expiration: 2029-09-06

Abstract

The utility model discloses a LED lamp light sense adjusts constant current circuit is including the unsteady state multivibrator circuit that is used for exporting the PWM signal based on NE555 chip to and be used for receiving the PWM signal and export the LED constant current drive circuit of stabilizing the constant current, wherein, unsteady state multivibrator circuit includes the NE555 chip, the charge-discharge circuit who is coupled with the NE555 chip and couple the photo resistance RG1 between power and charge-discharge circuit. The utility model discloses utilize the NE555 chip and the charge-discharge circuit who is coupled with the NE555 chip and the photo resistance RG1 of coupling between power and charge-discharge circuit directly generates the PWM signal and adjusts luminance, and rethread LED constant current drive circuit realizes that the PWM signal adjusts luminance, need not to reconnect other converting circuit, simple structure, and is with low costs.

Description

LED light sense adjusting constant current circuit based on NE555 chip

Technical Field

The utility model relates to a regulating circuit is felt to LED light particularly, relates to a LED light feels adjusts constant current circuit based on NE555 chip.

Background

Due to the advantages of high luminous efficiency, long service life, safety, energy conservation, no pollution and the like, the LED is widely applied to the lighting industry in recent years, particularly the development of LED driving dimming technology, and dimming can effectively utilize energy and save energy. There are three main ways of dimming LEDs on the market: firstly, linear dimming, secondly silicon controlled rectifier dimming, thirdly PWM signal dimming, and PWM signal dimming more accords with people to the requirement of LED precision, efficiency and effect of adjusting luminance. At present, the PWM signal dimming mainly has the following two ways, one is realized by adopting a single chip microcomputer, and although a good effect is obtained, the cost is inevitably increased; secondly, a special chip such as SJT0801 is adopted, but the phenomena of the reduction of the service life of the LED and the like caused by unstable factors such as jump voltage and the like caused by the instant starting cannot be avoided.

In view of the above-mentioned problem of dimming with PWM signals, patent document CN204046880U discloses a novel LED dimming circuit, which utilizes an NE555 chip to generate a sawtooth wave, converts the sawtooth wave into dimming with PWM signals through an LTH35 voltage comparator, and then implements dimming with PWM signals through a high-performance LED constant current driving chip PT 4115. Although the cost can be reduced and the stability can be improved by using the above technology for dimming the LED, the circuit needs to convert the sawtooth wave generated by the NE555 chip into the PWM signal through the LTH35 voltage comparator for dimming, the whole circuit structure is complicated, and the improvement is needed.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to the above-mentioned defect among the prior art, provide a simple structure's LED light sense adjusts constant current circuit based on NE555 chip.

In order to realize the purpose of the utility model, the utility model adopts the following technical scheme:

the LED lamp light sense adjusting constant current circuit based on the NE555 chip comprises an astable multivibrator circuit used for outputting a PWM signal and an LED constant current driving circuit used for receiving the PWM signal and outputting a stable constant current, wherein the astable multivibrator circuit comprises the NE555 chip, a charging and discharging circuit coupled with the NE555 chip and a photoresistor RG1 coupled between a power supply and the charging and discharging circuit.

Furthermore, the utility model discloses still provide following subsidiary technical scheme:

the charging and discharging circuit comprises a potentiometer RP1, a diode D1, a resistor R1 and a capacitor C1, wherein the head end of the potentiometer RP1 is coupled with a photosensitive resistor RG1, the center end of the potentiometer RP1 is coupled with the 7 th pin of the NE555 chip and the anode of a diode D1 respectively, the tail end of the potentiometer RP1 is coupled with the cathode of the diode D1 and one end of the resistor R1 respectively, the anode of the capacitor C1 is coupled with the other end of the resistor R1 and the 2 nd and 6 th pins of the NE555 chip respectively, and the cathode of the capacitor C1 is grounded.

The photoresistor RG1 is model MG 42-17.

The model of the diode D1 is 1N 4007.

The capacitor C1 is an electrolytic capacitor with a capacitance value of 0.001 μ F.

The astable multivibrator circuit further comprises a capacitor C2, wherein the anode of the capacitor C2 is coupled with the 5 th pin of the NE555 chip, and the cathode of the capacitor C2 is grounded.

The capacitor C2 is an electrolytic capacitor with a capacitance value of 0.001 μ F.

The LED constant current driving circuit comprises a PT4115 chip, a current sampling circuit, an inductor L1 and a diode D2, wherein the pin 8 of the PT4115 chip is coupled with an astable multivibrator circuit, the current sampling circuit is coupled between a power supply and the pin 1 of the PT4115 chip, the inductor L1 is used for ballasting, and the diode D2 is used for freewheeling.

The current sampling circuit comprises a photoresistor RG2 and a potentiometer RP2, wherein the photoresistor RG2 is coupled between a power supply and the head end of the potentiometer RP2, the center end of the potentiometer RP2 is coupled with the tail end, and the tail end of the potentiometer RP2 is further coupled with the No. 1 pin of the PT4115 chip.

The LED constant current driving circuit further comprises a capacitor C3, and the capacitor C3 is coupled between the inductor and the No. 3 pin of the PT4115 chip.

Compared with the prior art, the utility model has the advantages that:

the NE555 chip, the charging and discharging circuit coupled with the NE555 chip and the photoresistor RG1 coupled between the power supply and the charging and discharging circuit are used for directly generating PWM signals for dimming, and then the PWM signals for dimming are realized through the LED constant current driving circuit, and other conversion circuits do not need to be connected, so that the structure is simple, and the cost is low.

Drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments or related technologies will be briefly introduced below, and it is obvious that the drawings in the following description only relate to some embodiments of the present invention and are not limiting to the present invention.

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the present invention, taken in conjunction with the accompanying drawings and the detailed description, is given in a non-limiting manner.

As shown in fig. 1, the LED lamp light-sensing adjustment constant current circuit based on the NE555 chip of the present embodiment includes an astable multivibrator circuit and an LED constant current driving circuit, which are coupled to each other, wherein the astable multivibrator circuit is mainly used for outputting a PWM signal, and the LED constant current driving circuit is mainly used for receiving the PWM signal and is controlled by the PWM signal to output a stable constant current. The astable multivibrator circuit has a light sensation adjusting function and can output PWM signals only under the condition of adjusting the light sensation within a specific range.

The astable multivibrator circuit comprises an NE555 chip U1, a charging and discharging circuit, a photoresistor RG1 and a capacitor C2, wherein the charging and discharging circuit further comprises a potentiometer RP1, a diode D1, a resistor R1 and a capacitor C1. The 4 th pin and the 8 th pin of the NE555 chip U1 are respectively coupled with a power supply VCC, one end of a photoresistor RG1 is respectively coupled with the power supply and the 4 th pin of U1, the other end of the photoresistor is coupled with the head end of a potentiometer RP1, the center end of the potentiometer RP1 is respectively coupled with the 7 th pin of the NE555 chip and the anode of a diode D1, the tail end of the photoresistor is respectively coupled with the cathode of a diode D1 and one end of a resistor R1, the anode of a capacitor C1 is respectively coupled with the other end of a resistor R1 and the 2 nd and 6 th pins of the NE555 chip, and the cathode of the capacitor C1 is grounded. The positive pole of the capacitor C2 is coupled with the 5 th pin of the NE555 chip, and the negative pole is grounded. The output duty cycle of pin 3 of the NE555 chip U1 can be adjusted using RP1, with higher duty cycle meaning higher bulb brightness and lower duty cycle meaning lower lamp brightness. When the circuit works, the light-sensitive resistor RG1 in the astable multivibrator circuit senses the illumination intensity in the environment, and adjusts the charges passing through the upper half parts of the R1 and the RP1 and the capacitor C1 according to the illumination intensity, so that the output end of the U1 of the NE555 chip outputs different pulse electric signals. In this embodiment, the photosensitive resistor RG1 is MG42-17, the diode D1 is 1N4007, the potentiometer RP1 is a 103-type potentiometer, the resistor R1 has a resistance of 1K, the capacitors C1 and C2 are electrolytic capacitors, and the capacitance values are 0.01 μ F, respectively.

The LED constant current driving circuit comprises a PT4115 chip, a current sampling circuit, an inductor L1, a diode D2 and a capacitor C3, wherein the current sampling circuit comprises a photosensitive resistor RG2 and a potentiometer RP 2. The pin 8 of the PT4115 chip is coupled to the pin 3 of the NE555 chip U1 through a resistor R2 (with a resistance of 1K), the photo resistor RG2 is coupled between the power supply and the head end of the potentiometer RP2, the center end of the potentiometer RP2 is coupled to the tail end, the tail end of the potentiometer RP2 is further coupled to the pin 1 of the PT4115 chip, the inductor L1 is coupled to the LED1 for ballasting, and the diode D2 is used for freewheeling. The capacitor C3 is coupled between the inductor and pin 3 of the PT4115 chip. The current sampling circuit can enable the LED lamp to emit stable luminosity; adjusting RP2 may also limit the maximum brightness of the LED at a certain ambient light intensity. When the PT4115 chip U2 works, when the 8 th pin DIM receives a negative pulse electric signal, the circuit works in a circuit lower than 0.3V, and the built-in power switch is in a standby state, so that a lamp is not on; when the 8-pin DIM of the PT4115 chip U2 receives a negative pulse electric signal, the circuit works in a circuit higher than 0.3V, a built-in power switch is conducted, and an LED lamp is lightened. In this embodiment, the diode D2 is a schottky diode model SS14, the photo resistor RG2 is a schottky diode model MG42-17, the potentiometer RP2 is a 103 potentiometer, the inductor L1 has a value of 100mH, and the capacitor C3 is a 103 capacitor.

The utility model discloses a theory of operation is: the photoresistor RG1 senses the illumination intensity in the current environment, when the real-time environment illumination intensity is strong, the photoresistor RG1 adjusts the charges passing through the upper half parts of R1 and RP1 and the capacitor C1, when the voltage at the two ends of the capacitor C1 reaches 2/3 of VCC, the output of the internal upper comparator is turned over, the internal trigger switches the output result, the output end of the NE555 chip U1 becomes a negative pulse electrical signal, at the moment, the DIM of the 8 th pin of the PT4115 chip U2 works in a circuit lower than 0.3V, and the built-in power switch is in a standby state, so that the lamp is not bright; when the real-time environment is in weak illumination, because the internal trigger is set, the current passes through R1, when the capacitor starts to discharge, the lower half of RP1 flows into the discharge pin, when the voltage across the capacitor C1 becomes 1/3 of VCC, the lower comparator overturns the output of the capacitor, and the internal trigger switches the output of the capacitor again, so that the astable multivibrator U1 outputs a positive pulse electrical signal, at the moment, the 8-pin DIM of the PT4115 chip U2 works in a circuit higher than 0.3V, the built-in power switch is turned on, and the LED lamp is turned on.

It should be noted that the above-mentioned preferred embodiments are only for illustrating the technical concepts and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, and the protection scope of the present invention cannot be limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The utility model provides a LED lamp light feels and adjusts constant current circuit based on NE555 chip which characterized in that: the LED constant current drive circuit comprises an astable multivibrator circuit used for outputting a PWM signal and an LED constant current drive circuit used for receiving the PWM signal and outputting a stable constant current, wherein the astable multivibrator circuit comprises an NE555 chip, a charging and discharging circuit coupled with the NE555 chip and a photoresistor RG1 coupled between a power supply and the charging and discharging circuit.

2. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 1, wherein: the charging and discharging circuit comprises a potentiometer RP1, a diode D1, a resistor R1 and a capacitor C1, wherein the head end of the potentiometer RP1 is coupled with a photosensitive resistor RG1, the center end of the potentiometer RP1 is coupled with the 7 th pin of an NE555 chip and the anode of a diode D1 respectively, the tail end of the potentiometer RP1 is coupled with the cathode of the diode D1 and one end of the resistor R1 respectively, the anode of the capacitor C1 is coupled with the other end of the resistor R1 and the 2 nd and 6 th pins of the NE555 chip respectively, and the cathode of the capacitor C1 is grounded.

3. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 1 or 2, wherein: the photosensitive resistor RG1 is MG 42-17.

4. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 2, wherein: the model of the diode D1 is 1N 4007.

5. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 2, wherein: the capacitor C1 is an electrolytic capacitor with a capacitance value of 0.001 muF.

6. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 1, wherein: the astable multivibrator circuit further comprises a capacitor C2, wherein the anode of the capacitor C2 is coupled with the 5 th pin of the NE555 chip, and the cathode of the capacitor C2 is grounded.

7. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 6, wherein: the capacitor C2 is an electrolytic capacitor with a capacitance value of 0.001 muF.

8. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 1, wherein: the LED constant current driving circuit comprises a PT4115 chip, a current sampling circuit, an inductor L1 and a diode D2, wherein the 8 th pin of the PT4115 chip is coupled with an astable multivibrator circuit, the current sampling circuit is coupled between a power supply and the 1 st pin of the PT4115 chip, the inductor L1 is used for ballasting, and the diode D2 is used for freewheeling.

9. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 8, wherein: the current sampling circuit comprises a photoresistor RG2 and a potentiometer RP2, wherein the photoresistor RG2 is coupled between a power supply and the head end of the potentiometer RP2, the center end of the potentiometer RP2 is coupled with the tail end, and the tail end of the potentiometer RP2 is further coupled with the No. 1 pin of the PT4115 chip.

10. The LED lamp light sense regulation constant current circuit based on the NE555 chip as claimed in claim 8, wherein: the LED constant current driving circuit further comprises a capacitor C3, and the capacitor C3 is coupled between the inductor and the No. 3 pin of the PT4115 chip.