CN218183560U

CN218183560U - PWM dimming circuit for LED

Info

Publication number: CN218183560U
Application number: CN202222314860.5U
Authority: CN
Inventors: 马贵林; 马瑞芳; 马瑞杰; 施春华; 孟伟
Original assignee: Shanghai Musa Electronic Technology Co ltd
Current assignee: Shanghai Musa Electronic Technology Co ltd
Priority date: 2022-09-01
Filing date: 2022-09-01
Publication date: 2022-12-30
Anticipated expiration: 2032-09-01

Abstract

The application relates to a PWM dimming circuit for LEDs, which comprises a plurality of LED lamps and a power input unit, wherein the power input unit is electrically connected to an external power supply and is used for converting the external power supply into voltage used by the LED lamps; the LED lamp control system comprises a control unit, wherein the control unit comprises a control chip U1, the LED lamps are electrically connected with the control chip U1 used for controlling the LED lamps, the control chip U1 is electrically connected with a download interface unit used for downloading the working programs of the LED lamps, and the download interface unit is electrically connected with a computer. This application has the work of making control chip U1 direct electric connection in LED lamp control LED lamp, has avoided producing the distortion after the opto-coupler transmission, has become the pulse signal of distortion, therefore can change the procedure according to the demand and can adjust luminance to the LED lamp, has reached the effect of linear adjusting luminance.

Description

PWM dimming circuit for LED

Technical Field

The utility model belongs to the technical field of the technique of LED equipment of adjusting luminance and specifically relates to a PWM dimmer circuit for LED is related to.

Background

The LED is called a fourth generation light source, has the characteristics of energy conservation, environmental protection, safety, long service life, low power consumption, low heat, high brightness, water resistance, micro size, shock resistance, easiness in dimming, light beam concentration, simplicity and convenience in maintenance and the like, and can be widely applied to the fields of various indications, display, decoration, backlight sources, common illumination and the like.

There are three main ways of LED dimming currently on the market: the linear dimming, the silicon controlled dimming and the PWM dimming are adopted. Of these three dimming approaches, PWM (pulse width modulation) dimming technology is currently considered to be the most promising LED dimming technology.

When performing PWM dimming, an external PWM signal source is provided. The output of the LED driving power supply is adjusted by changing the duty ratio of the input pulse signal, so that the current passing through the LED is adjusted, and the light emitting characteristic of the LED is adjusted. The dimming technology has the advantages of simple application, high efficiency, high precision and good dimming effect.

Current PWM dimming circuits typically use opto-isolator. However, in the PWM dimming circuit using optocoupler isolation, because the additional PWM dimming signal is a switching signal, and the common optocoupler works in a nonlinear state (the optocoupler transistor has a storage time of charges), the PWM dimming signal is distorted after being transmitted through the optocoupler, and becomes a distorted pulse signal, thereby reducing the linearity of dimming.

SUMMERY OF THE UTILITY MODEL

Produce the distortion after using the opto-coupler transmission in order to improve current PWM dimmer circuit, become the pulse signal of distortion, reduce the phenomenon of the linearity of adjusting luminance, the utility model provides a PWM dimmer circuit for LED.

The utility model provides a pair of a PWM dimmer circuit for LED adopts following technical scheme:

a PWM dimming circuit for LEDs comprises a plurality of LED lamps and a power input unit, wherein the power input unit is electrically connected to an external power supply and is used for converting the external power supply into voltage used by the LED lamps;

the LED lamp control system comprises a control unit, wherein the control unit comprises a control chip U1, the LED lamps are electrically connected with the control chip U1 used for controlling the LED lamps, the control chip U1 is electrically connected with a download interface unit used for downloading the working programs of the LED lamps, and the download interface unit is electrically connected with a computer.

By adopting the technical scheme, the control chip U1 is directly and electrically connected with the plurality of LED lamps,

the LED lamp control system is connected with a computer through a download interface unit, a control program for controlling the working mode of the LED lamp is stored in the control chip U1 in advance, so that the control chip U1 outputs square wave signals with different duty ratios, the time of the electric quantity of the LED lamp is directly controlled according to the duty ratios, and the display state of the lamp is adjusted. Because the control chip U1 is directly and electrically connected to the LED lamp to control the LED lamp to work, the mode of optical coupling isolation is not used, distortion generated after optical coupling transmission is avoided, and the distortion is changed into a distorted pulse signal, so that programs can be changed according to requirements to adjust the light of the LED lamp, and the purpose of linear light adjustment is achieved.

Preferably, the control chip U1 is electrically connected to a lamp interface unit for connecting the LED lamp, and the lamp interface unit is provided with a USB interface.

By adopting the technical scheme, the lamp interface unit is arranged in the electrical property of the control chip U1, and the USB interface is arranged on the lamp interface, so that the adaptability of the lamp interface unit to the lamp is improved.

Preferably, the control chip U1 is electrically connected to a clock unit for providing a clock signal to the control chip U1, and the clock unit includes a real-time clock chip U4.

By adopting the technical scheme, the clock unit can provide a real-time clock signal for the control chip U1, so that the control chip U1 can accurately output square wave signals with different duty ratios according to a program, and the working state of the LED lamp is controlled.

Preferably, the control chip U1 is electrically connected to an infrared interface unit, and the infrared interface unit is electrically connected to an infrared sensing device for detecting whether a person is using near the LED lamp.

Through adopting above-mentioned technical scheme, there is infrared induction system at control chip U1 through infrared interface unit electric connection, utilizes near infrared induction system response lamps and lanterns whether someone uses, with in detecting signal transmission to control chip U1. When no person is detected to exist near the lamp, the control chip U1 is made to change the working mode of the LED lamp, so that the functions of saving electricity and energy are achieved.

Preferably, the control chip U1 is electrically connected to a key unit for changing the operating mode of the LED lamp.

By adopting the technical scheme, the key unit is pressed, the control chip U1 is enabled to change the working modes of the plurality of LED lamps through the set program by utilizing different control signals output by the key unit, and the working modes comprise an automatic mode and a manual mode so as to improve the adaptability of the lamp to various conditions.

Preferably, the control chip U1 is electrically connected to a display unit for displaying the working information of the LED lamp.

Through adopting above-mentioned technical scheme, utilize the display element to carry out real-time display with the work information of LED lamp to the staff observes the debugging circuit.

Preferably, the control chip U1 is electrically connected to an expansion IO unit for expansion work.

By adopting the technical scheme, the control chip U1 is electrically connected with the expansion IO unit, so that new functions can be added to the circuit by using the expansion IO unit, and the expansion capability of the circuit is improved.

Preferably, the control chip U1 is electrically connected to a collection unit for collecting ambient brightness, and the collection unit is electrically connected to an AD collection unit for converting analog quantity to digital quantity.

By adopting the technical scheme, when the circuit normally works, the acquisition unit acquires the brightness in the environment in real time, and further when the environment brightness is lower, the brightness of the LED lamp controlled by the control chip U1 is brighter, and when the brightness of the environment is higher, the brightness of the LED lamp controlled by the control chip U1 is darker.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the control chip U1 is directly and electrically connected to the LED lamp to control the LED lamp to work, distortion generated after transmission of the optical coupler is avoided, and the distortion is changed into a distorted pulse signal, so that programs can be changed according to requirements to adjust the light of the LED lamp, and the aim of linear light adjustment is fulfilled;

2. the control chip U1 is electrically connected with an infrared sensing device through an infrared interface unit, the infrared sensing device is used for sensing whether people use nearby the lamp, and when no people exist nearby the lamp, the control chip U1 is made to change the working mode of the LED lamp, so that the functions of saving electricity and energy are achieved.

Drawings

FIG. 1 is a circuit diagram of a power input unit in the present embodiment;

FIG. 2 is a schematic circuit diagram of a control unit according to the present embodiment;

FIG. 3 is a schematic circuit diagram of a lamp interface unit, a clock unit and a key unit in the present embodiment;

FIG. 4 is a schematic circuit diagram of the acquisition unit and the infrared interface unit in this embodiment;

fig. 5 is a circuit diagram of the display unit in the present embodiment.

Description of the reference numerals: 10. a power input unit; 20. a control unit; 21. a download interface unit; 30. a lamp interface unit; 40. a clock unit; 50. a key unit; 60. a collection unit; 70. an infrared interface unit; 80. a display unit; 90. and expanding the IO unit.

Detailed Description

The present application is described in further detail below with reference to figures 1-5.

A PWM dimming circuit for an LED (light emitting diode) comprises a power input unit 10, wherein an input end of the power input unit 10 is electrically connected to an external power supply, an output end of the power input unit 10 is electrically connected to other units, and the power input unit 10 is used for obtaining the external power supply and converting the voltage of the external power supply into the voltage which can be used by circuit unit elements.

Referring to fig. 1, in detail, the power input unit 10 includes pin header interface terminals, a WJ128 connection terminal, and a miniUSB interface terminal. The pin header interface terminal can be used for supplying power to a DuPont wire; the WJ128 wire terminal can be used in the case of bare power supply; the miniUSB interface terminal can use the connecting wire that has the miniUSB interface to connect, and miniUSB interface terminal has the volume great, and is connected more firmly with the circuit board, connects ground more stably, is favorable to making connecting wire and miniUSB interface terminal carry out plug many times on the circuit board. The power input unit 10 includes three different interface modes, so that the power input unit 10 can be connected in different modes according to different situations.

Referring to fig. 1 and 2, the power input unit 10 is electrically connected to a control unit 20 storing a control program, the control unit 20 includes a control chip U1, and a peripheral circuit is electrically connected to a periphery of the control chip U1. The control chip U1 is electrically connected to a download interface unit 21 for downloading the transmission control program, and the download interface unit 21 includes connection terminals P2 and P4 for connecting to a downloader. In this embodiment, the connection terminals P2 and P4 adopt XH2.54 terminal sockets, so that the connection terminals can be directly connected by using an XH2.54 connection wire, thereby avoiding wrong insertion. The connection terminals P2 and P4 are electrically connected to the reading terminal and the receiving terminal of the control chip U1, respectively.

Referring to fig. 2 and 3, the control chip U1 is electrically connected to the lamp interface unit 30, the lamp interface unit 30 includes a USB interface J2 for connecting a lamp having a USB interface, a GND terminal of the USB interface J2 is electrically connected to the triode Q3, the GND terminal is electrically connected to an emitter of the triode Q3, a collector of the triode Q3 is grounded, and a base of the triode Q3 is electrically connected to the P3.5 pin terminal of the control chip U1 after being connected to the resistor R15 in series. The type of the triode Q3 is a PNP type triode, and the triode Q3 works in an amplification area.

Referring to fig. 3, the usb interface J2 is connected to a plurality of LED lamps, and the control chip U1 changes the base current of the triode Q3 by outputting square wave signals with different duty ratios, and then controls the current flowing between the emitter and the collector, thereby changing the brightness of the LED lamps and realizing the control of the LED lamps.

Referring to fig. 2 and 3, the control chip U1 is electrically connected to a clock unit 40 for providing a real-time clock signal to the control chip U1, the clock unit 40 includes a clock chip U4, and the model of the clock chip U4 is DS1302. The serial clock end of the clock chip U4 is electrically connected to the P1.0 pin of the control chip U1, the I/O output end of the clock chip U4 is electrically connected to the P1.1 pin of the control chip U1, the reset end of the clock chip U4 is electrically connected to the P1.2 pin of the control chip U1, and the crystal oscillator pin of the clock chip U4 is electrically connected to the crystal oscillator X2.

Referring to fig. 2 and 3, the control chip U1 is electrically connected to a key unit 50 for changing the operating mode of the control chip U1 for controlling the LED lamp, and the key unit 50 includes a key S3, a key S4, a key S5, and a key S6. One ends of the keys S3, S4, S5 and S6 are connected in parallel and grounded, and the other ends of the keys S3, S4, S5 and S6 are respectively and electrically connected to pins P2.2, P2.3, P2.4 and P2.2 of the control chip U1. The working mode of the LED lamp is changed by pressing different key combinations. In the embodiment, the LED lamp has four working modes, namely (a) automatic switching and automatic brightness adjustment; (b) a manual switch for automatically adjusting the brightness; (c) automatic switch, adjust the luminance manually; and (d) a manual switch for manually adjusting the brightness.

Referring to fig. 2 and 4, the control chip U1 is electrically connected to a collecting unit 60 for collecting brightness and brightness of light near the lamp, the collecting unit 60 includes a photo resistor R3, one end of the photo resistor R3 is electrically connected to VDD of the power supply 5V after being connected in series to a resistor R12 for voltage division, and the other end of the photo resistor R3 is grounded. The AD acquisition unit 60 is electrically connected between the photoresistor R3 and the resistor R12 and used for converting analog quantity into digital quantity, the AD acquisition unit 60 comprises an analog-to-digital conversion chip U6, and the model of the analog-to-digital conversion chip U6 is ADS1015IDGSR. The data end of the analog-to-digital conversion chip U6 is electrically connected to the P2.0 pin of the control chip U1, and the control end of the analog-to-digital conversion chip U6 is electrically connected to the P2.1 pin of the control chip U1.

The resistance value of the photoresistor R3 is controlled by the illumination brightness of the environment and changes along with the brightness change of the environment, so that the point potential between the photoresistor R3 and the resistor R12 changes, and the voltage value of the point potential is uploaded to the analog-to-digital conversion chip U6, so that the analog-to-digital conversion chip U6 has the functions of data acquisition and analog-to-digital conversion. Under the mode of automatically adjusting the brightness, the control chip U1 can automatically adjust the brightness of the LED lamp according to the brightness of the environment, and when the brightness of the environment is brighter, the brightness of the LED lamp is controlled to be lower. When the brightness of the environment is darker, the brightness of the LED lamp is controlled to be brighter.

Referring to fig. 2 and 4, the control chip U1 is electrically connected to an infrared interface unit 70 for detecting whether a person is near the LED lamp, the infrared interface unit 70 includes an infrared interface terminal P5, a pin 2 terminal of the infrared interface terminal P5 is electrically connected to a triode Q2 after being connected in series with a resistor R14, the resistor R14 is electrically connected to a base of the triode Q2, an emitter of the triode Q2 is electrically connected to a VDD power supply of 5V after being connected in series with a resistor R13, and a collector of the triode Q2 is grounded. The emitter of the triode Q2 is also electrically connected to a P1.3 pin of the control chip U1. The infrared sensing device is electrically connected with the control chip U1 through the infrared interface unit 70, and when the infrared sensing device detects that someone near the LED lamp uses the LED lamp, the brightness of the LED lamp is normal brightness. When the infrared sensing device detects that no one near the LED lamp uses the LED lamp, the brightness of the LED lamp is reduced to reduce power consumption.

Referring to fig. 2 and 5, the control chip U1 is electrically connected to a display unit 80 for displaying the operating information of the LED lamp, the display unit 80 includes a liquid crystal display Q1, and the type of the liquid crystal display Q1 is LCD1602. And the liquid crystal display screen Q1 is electrically connected with the signal output end of the control chip U1. The working information of the LED lamp is displayed by the liquid crystal display screen Q1 in real time, and the working state of elements in the circuit can be conveniently checked by a worker.

Referring to fig. 2 and 5, the control chip U1 is electrically connected to an expansion IO unit 90 for implementing an expansion function, the expansion IO unit 90 includes an interface unit P3, and a data transmission pin of the interface unit P3 is electrically connected to pins P1.4, P1.5, P1.6, and P1.7 of the control chip U1, respectively, so as to facilitate other expansions of the functions of the circuit to enrich the functions of the circuit.

The implementation principle of the application is as follows: firstly, the control chip U1 is electrically connected to the downloader through the download interface unit 21, and then the control program for controlling the LED lamp is burned into the control chip U1. The LED lamp is connected to the circuit through the lamp interface unit 30, and the infrared detection device is connected to the infrared interface unit 70.

When the circuit controls the LED lamp to work, the corresponding working mode is selected by pressing a key in the key unit 50, so that the control chip U1 outputs square wave signals with different duty ratios to drive the LED lamp to light for a certain time. When the LED lamp is in the automatic brightness adjusting mode, the brightness of the LED lamp can be automatically adjusted according to the brightness of the environment, whether a person uses the LED lamp and the brightness of the LED lamp is automatically adjusted by the aid of the infrared detection device, and the purpose of energy conservation is achieved.

The above are preferred embodiments of the present application, and the scope of protection of the present application is not limited thereto, so: equivalent changes in structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a PWM dimmer circuit for LED, includes a plurality of LED lamp, its characterized in that: the LED lamp comprises a power input unit (10), wherein the power input unit (10) is electrically connected to an external power supply, and the power input unit (10) is used for converting the external power supply into voltage used by the LED lamp;

the LED lamp control system comprises a control unit (20), wherein the control unit (20) comprises a control chip U1, the LED lamp is electrically connected with the control chip U1 used for controlling the LED lamp, the control chip U1 is electrically connected with a download interface unit (21) used for downloading an LED lamp working program, and the download interface unit (21) is electrically connected with a computer.

2. The PWM dimming circuit for an LED according to claim 1, wherein: the LED lamp control device is characterized in that the control chip U1 is electrically connected with a lamp interface unit (30) used for being connected with the LED lamp, and a USB interface is arranged on the lamp interface unit (30).

3. The PWM dimming circuit for an LED according to claim 1, wherein: the control chip U1 is electrically connected with a clock unit (40) used for providing clock signals for the control chip U1, and the clock unit (40) comprises a real-time clock chip U4.

4. The PWM dimming circuit for LEDs according to claim 1, wherein: the LED lamp control system is characterized in that the control chip U1 is electrically connected with an infrared interface unit (70), and the infrared interface unit (70) is electrically connected with an infrared induction device for detecting whether people are near the LED lamp or not.

5. The PWM dimming circuit for an LED according to claim 1, wherein: the control chip U1 is electrically connected with a key unit (50) for changing the working mode of the LED lamp.

6. The PWM dimming circuit for LEDs according to claim 1, wherein: the control chip U1 is electrically connected with a display unit (80) for displaying the working information of the LED lamp.

7. The PWM dimming circuit for an LED according to claim 1, wherein: the control chip U1 is electrically connected with an expansion IO unit (90) used for expansion work.

8. The PWM dimming circuit for an LED according to claim 1, wherein: the control chip U1 is electrically connected with a collecting unit (60) for collecting the ambient brightness, and the collecting unit (60) is electrically connected with an AD collecting unit (60) for converting the analog quantity into the digital quantity.