CN112333887A

CN112333887A - LED drive circuit

Info

Publication number: CN112333887A
Application number: CN202011096294.4A
Authority: CN
Inventors: 白旭; 张池; 陈伟
Original assignee: Shenzhen Zhuanyi Technology Co ltd
Current assignee: Shenzhen Zhuanyi Technology Co ltd
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2021-02-05
Anticipated expiration: 2040-10-14
Also published as: CN112333887B

Abstract

The invention discloses a driving circuit of an LED, which comprises a power input unit, a PWM control unit and a control IC unit, wherein the power input unit is respectively connected with the PWM control unit and the control IC unit, the PWM control unit is connected with the control IC unit, the PWM control unit can control the current or time of the driving circuit, and the control IC unit is connected with an LED product and provides constant current for the LED product. The invention can provide current compensation for the LED at any time through program control.

Description

LED drive circuit

Technical Field

The invention relates to the field of LED lamps, in particular to a drive circuit of an LED.

Background

UVC (200 nm-deep ultraviolet 280nm) LED related application products on the market at present all use constant current to drive LEDs. The disadvantages of this drive are: 1. when the LED is set to operate continuously, it takes a long time to achieve the effect due to natural light decay. 2. Considering the service life, in the initial stage of design, a product with the actual specification at least 200% larger than the actual design specification is required to be selected for use, and then the natural light decay time is calculated to ensure the actual service life of the product; meanwhile, when the LED is applied, the LED with a magnitude larger than the design requirement is selected for application, so that the cost is high; because the attenuation of the LED to 70% of the original value is only thousands of hours, that is, the effective sterilization life of the application product is thousands of hours, the requirement of the current market for the application of the product cannot be met basically, because the practical application needs to be more than 10000 hours at least. 3. Meanwhile, similar products on the market are single applications, no feedback signal source is provided for terminal users, LED products are usually installed in a closed device, and whether the LED works normally or not cannot be observed conveniently.

Disclosure of Invention

In view of the shortcomings of the prior art, the present invention provides a driving circuit of an LED capable of using program control and having a current compensation function.

The invention is realized by the following technical scheme:

the utility model provides a drive circuit of LED, includes power input unit, drive circuit still includes PWM the control unit and controls IC unit, power input unit respectively with PWM the control unit with control IC unit links to each other, PWM the control unit can be right drive circuit's electric current or time are controlled, control IC unit links to each other with the LED product, and right the LED product provides constant current.

Further, the PWM control unit is directly connected with the LED product.

Further, the power supply control circuit further comprises a filtering unit, wherein the filtering unit is connected between the power supply input unit and the control IC unit.

Furthermore, the PWM control circuit further comprises a feedback unit, and the feedback unit is connected with the PWM control unit.

Further, the filtering unit comprises capacitors C2 and C4, the capacitors C2 and C4 are connected in parallel, input ends of the capacitors C2 and C4 are connected with the power input unit, and an output end of the capacitor C4 is grounded.

Further, the control IC unit comprises a chip U2, resistors R1 and R3 and an inductor L1, the resistors R1 and R3 are connected in parallel, and the chip U2 is connected with the output end of the inductor L1.

Further, the U2 includes a pin VIN terminal, a CS terminal, a DIM terminal, a SW terminal, and a GND terminal, the input terminals of the resistors R1 and R3 are connected to the pin VIN terminal of the U2, the output terminals of the resistors R1 and R3 are connected to the CS terminal of the pin U2, the SW terminal of the pin U2 is connected to the input terminal of the inductor L1, and the GND terminal of the pin U2 is grounded.

Further, the PWM control unit includes a chip U1, and the chip U1 is connected to the chip U2.

Further, the chip U1 includes a pin timer terminal, a VSS terminal, a VDD terminal, a FB terminal, a PWM terminal, resistors R2, R5, and a capacitor C5, the pin timer terminal of the chip U1 is connected to 5V voltage through the resistor R2, the pin timer terminal of the chip U1 is grounded through the capacitor C5, the pin VSS terminal of the chip U1 is grounded, the pin VDD terminal of the chip U1 is connected to 5V voltage, the pin FB terminal of the chip U1 is grounded through the resistor R5, and the pin PWM terminal of the chip U1 is connected to the DIM terminal of the pin U2.

Further, the PWM control unit further includes a chip U3, and the chip U3 is connected to the chip U1.

Furthermore, the chip U3 includes a pin VIN terminal, a VOUT terminal and a GND terminal, the pin VIN terminal of the chip U3 is connected with 24V voltage, the pin VOUT terminal of the chip U3 is connected with the pin VDD terminal of the chip U1, and the GND terminal of the pin U3 is grounded.

Further, an LED product or a UVCLED product having a driver circuit with any of the above features.

Compared with the prior art, the invention has the advantages that:

1. the U1 chip with programmable time control capability is adopted to achieve the effect of realizing continuous compensation and accumulated compensation current through software programming.

2. Through the feedback unit, the user can observe the working state of the LED more conveniently.

3. Through the PWN control circuit and the control IC unit, stable current compensation can be automatically provided within any time period for the working requirement of the LED product.

Drawings

FIG. 1 is a block diagram of a driving circuit of an LED according to an embodiment of the present invention;

FIG. 2 is a circuit diagram of a driving circuit of an LED according to an embodiment of the present invention;

FIG. 3 is a circuit pin diagram of a chip U1 according to an embodiment of the present invention;

fig. 4 is a pin diagram of a chip U3 according to an embodiment of the invention.

Detailed Description

The following non-limiting detailed description of the present invention is provided in connection with the preferred embodiments and accompanying drawings.

As shown in fig. 1, a driving circuit of an LED according to an embodiment of the present invention includes a power input unit, a filtering unit, a PWM control unit, a control IC unit, and a feedback unit, which can be used in an LED product or a UVCLED product. The power input unit is connected with the filtering unit, the power input unit is used for providing power voltage for the driving circuit, the filtering unit can filter other noise signals to enable the input power frequency to be more stable, the filtering unit is connected with the control IC unit, the control IC unit controls one IC in the output current to enable the output current to be constant, the power input unit is also connected with the PWM control unit, the PWM control unit can control the current and time required by the circuit through software, the PWM control unit is connected with the control IC unit, a loop is formed among the power input unit, the filtering unit, the PWM control unit and the control IC unit, the feedback unit is connected with the PWM control unit, the feedback unit intercepts a working point from an LED working end, a judgment signal is provided for the terminal through the processing of the PWM control unit, the LED product can be directly connected with the control IC unit and the PWM control unit respectively, the LED product is operated by a constant current provided by the control IC unit, and the PWM control unit adjusts the current at a specific time point to achieve the use demand state.

As shown in fig. 2, the power input unit includes a connector CON3 and a diode D1, the connector CON3 includes a pin 1, a pin 2 and a pin 3, the pin 1 is an input end and outputs a 24V voltage, the pin 2 is grounded, the pin 3 is connected to a feedback signal, which can facilitate a user to monitor an operating state of the connector CON3, the diode D1 is connected to an input line of the pin 1 of the CON3 and is used for preventing the input end from being connected reversely, an external power supply supplies power to the entire driving circuit through the connector CON3, and after the voltage is input, the voltage passes through the device D1.

The filtering unit comprises capacitors C2 and C4, the capacitors C2 and C4 are connected in parallel, the input ends of the capacitors C2 and C4 are connected to an input line of a CON3 pin 1, and the other end of the capacitor C4 is grounded.

The control IC unit comprises a chip U2, resistors R1, R3 and an inductor L1, the chip U2 is a single chip microcomputer of a model PT4115, the chip U2 comprises a pin VIN end, a CS end, a DIM end, a SW end and a GND end, the resistors R1 and R3 are original sampling resistors of the U2, a resistor R1 is connected to an input line of a CON3 pin 1, the resistors R1 and R3 are connected in parallel, input ends of the resistors R1 and R3 are connected with the pin VIN end of the chip U2, output ends of the resistors R1 and R3 are connected with the pin CS end of the chip U2, the pin GND end of the chip U2 is connected, and the pin SW end of the chip U2 is connected with the input end of the inductor L1.

The filtering unit is arranged at pin 3 of CON3 and pin FB of chip U1, which is convenient for users to observe the working states of the input terminal, chip U1 and the whole circuit, thereby better controlling the driving circuit.

The LED driving circuit further comprises a diode D2, a capacitor C3, an output end CON2, resistors R4 and R6, and a zener diode Z2, wherein one end of the diode D2 is connected to an input end of the resistor R1, the other end of the diode D2 is connected to a SW end of a pin U2 of the chip, the output end CON2 comprises a pin 1 and a pin 2, the pin 1 of the CON2 is connected with the pin 1 of the CON3, the pin 2 of the CON2 is connected with an output end of an inductor L1, one end of the capacitor C3 is connected with the pin 1 of the CON2, the other end of the capacitor C3 is connected with the pin 2 of the CON2, the resistors R4 and R6 are connected to the pin 2 of the.

As shown in fig. 3-4, the PWM control unit includes a chip U1, resistors R2, R5, a capacitor C5, and a chip U3, the chip U1 is a single chip microcomputer of model MS51FSB9AE, the chip U1 includes a pin tie rst terminal, a VSS terminal, a VDD terminal, an FB terminal, and a PWM terminal, one side of the pin tie rst terminal of the chip U1 is connected to a 5V power supply through a resistor R2, the other side is grounded through a capacitor C5, the pin VSS terminal of the chip U1 is grounded, the pin VDD terminal of the chip U1 is connected to a 5V voltage, the FB terminal of the pin U1 is grounded through a resistor R5, and the PWM terminal of the pin U1 is connected to a pin DIM terminal of the chip U2. The chip U1 has programmable time control capability, and can realize two compensation mode signals, namely continuous compensation and accumulative compensation, for the driving circuit through software programming. The driving circuit is controlled by the single chip microcomputer, so that the control process is more accurate, a control program is arranged in the single chip microcomputer, and when a control signal sent by an external control panel is received, the current compensation can be automatically realized on the LED product. Chip U3 includes pin VIN end, VOUT end and GND end, and chip U3 pin VIN termination 24V voltage, and chip U3 pin VOUT end links to each other with chip U1 pin VDD end, and chip U3 pin GND end ground connection, chip U3 is the supply chip of full-time, provides the 5V voltage that self work needs for singlechip U1.

The chips U1, U2 and U3 realize automatic current compensation for the driving circuit, and the current compensation is divided into continuous compensation and accumulative compensation. Continuous compensation, when the LED product works, the amplitude can be reduced along with the change of working time and environment temperature, so that the initial value of the LED product is set to be 1.3 times of the normal value, the initial value is in the middle of the specification range of the LED product and is not too high, the continuous compensation is reset to zero after the LED product works, and when the LED product works again, the program is circulated. And accumulated compensation, necessary current compensation is carried out at a service life point according to an inherent service life curve of the LED product, the current compensation amplitude is not too large, multiple times of compensation can be carried out, and an upper limit point is set simultaneously so as not to damage the LED product due to too high current.

When the driving circuit works, a power supply is input through a connector CON3, filtered through a diode D1, filtered through capacitors C2 and C4 and transmitted to resistors R1 and R3, and then enters a VIN end of a pin U2 of a chip U, output is output from an SW end of a pin U2 of the chip U, and forms a loop with an output end CON2 through an inductor L1, the chip U1 is connected with the chip U2, the chip U1 realizes current compensation on the driving circuit through a control chip U2, the chip U3 is connected with a chip U1, the chip U3 provides 5V voltage required by work for the chip U1, after the driving circuit is electrified, the current of the driving circuit gradually rises, the voltage also gradually rises to a normal working mode of an LED product, when the LED product works for a certain period of time, light can be attenuated, after the chip U1 detects the voltage, the chip U2 is controlled, the current is added to the driving.

The invention provides an LED product with the driving circuit with any of the characteristics.

When the LED lamp is used, the PWM control is added on the basis of the prior art, the current compensation is realized on the LED product through the compensation points and the time periods required by the software computing circuit, the current compensation can enable the LED product to return to the original brightness again when the LED product is in light decay, the service life is prolonged, the working condition of the product is more conveniently monitored by a user by arranging the feedback signal source at the working end of the LED product, and the voltage and the current are not required to be added to the initial LED product, so that the cost can be reduced.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The LED driving circuit comprises a power input unit and is characterized by further comprising a PWM control unit and a control IC unit, wherein the power input unit is respectively connected with the PWM control unit and the control IC unit, the PWM control unit is connected with the control IC unit, the PWM control unit can control the current or time of the driving circuit, and the control IC unit is connected with an LED product and provides constant current for the LED product.

2. The LED driving circuit according to claim 1, wherein the PWM control unit is directly connected to the LED product.

3. The LED driving circuit according to claim 1, further comprising a filter unit connected between the power input unit and the control IC unit.

4. The LED driving circuit according to claim 1, further comprising a feedback unit, wherein the feedback unit is connected to the PWM control unit.

5. The LED driving circuit as claimed in claim 4, wherein the filtering unit comprises capacitors C2 and C4, the capacitors C2 and C4 are connected in parallel, the input terminals of the capacitors C2 and C4 are connected to the power input unit, and the output terminal of the capacitor C4 is connected to ground.

6. The LED driving circuit as claimed in claim 1, wherein the control IC unit comprises a chip U2, resistors R1 and R3 and an inductor L1, the resistors R1 and R3 are connected in parallel, and the chip U2 is connected with an output end of the inductor L1.

7. The LED driving circuit as claimed in claim 6, wherein the U2 comprises a VIN terminal, a CS terminal, a DIM terminal, a SW terminal and a GND terminal, the input terminals of the resistors R1 and R3 are connected to the VIN terminal of the U2 pin, the output terminals of the resistors R1 and R3 are connected to the CS terminal of the U2 pin, the SW terminal of the U2 pin is connected to the input terminal of the inductor L1, and the GND terminal of the U2 pin is connected to ground.

8. The LED driving circuit as claimed in claim 6, wherein the PWM control unit comprises a chip U1, and the chip U1 is connected to the chip U2.

9. The LED driving circuit as claimed in claim 8, wherein the chip U1 includes a TICERST terminal, a VSS terminal, a VDD terminal, a FB terminal and a PWM terminal, and resistors R2, R5 and a capacitor C5, the TICERST terminal of the chip U1 pin is connected to 5V voltage through the resistor R2, the TICERST terminal of the chip U1 pin is connected to ground through the capacitor C5, the VSS terminal of the chip U1 pin is connected to ground, the VDD terminal of the chip U1 pin is connected to 5V voltage, the FB terminal of the chip U1 pin is connected to ground through the resistor R5, and the PWM terminal of the chip U1 pin is connected to the DIM terminal of the chip U2.

10. The LED driving circuit as claimed in claim 9, wherein the PWM control unit further comprises a chip U3, and the chip U3 is connected to the chip U1.

11. The LED driving circuit as claimed in claim 10, wherein the chip U3 comprises a pin VIN terminal, a VOUT terminal and a GND terminal, the pin VIN terminal of the chip U3 is connected to a 24V voltage, the pin VOUT terminal of the chip U3 is connected to the pin VDD terminal of the chip U1, and the pin GND terminal of the chip U3 is connected to ground.

12. LED product or UVCLED product with a driver circuit according to any of claims 1 to 11.