CN212163788U

CN212163788U - LED control circuit and LED lamp capable of realizing gradual darkening

Info

Publication number: CN212163788U
Application number: CN202021229776.8U
Authority: CN
Inventors: 张庆煌; 陈洪新; 王文亮; 方金海
Original assignee: Xiamen Sunshine Iot Technology Co ltd
Current assignee: Xiamen Yankon Energetic Lighting Co Ltd
Priority date: 2020-06-29
Filing date: 2020-06-29
Publication date: 2020-12-15
Anticipated expiration: 2030-06-29

Abstract

The utility model relates to a LED technical field. The utility model discloses a LED control circuit and LED lamp for realizing gradual darkening, wherein, the LED control circuit for realizing gradual darkening comprises an LED drive circuit, the output end of the LED drive circuit is connected with an LED load, the LED drive circuit is provided with a drive control IC, the sampling end of the drive control IC is connected with a sampling resistance unit, the resistance value of the sampling resistance unit is variable, an energy storage element is arranged in the LED drive circuit, the LED lamp also comprises a rapid power-down detection circuit, the rapid power-down detection circuit is configured to control the resistance value of the sampling resistance unit to be switched from a first set value to a second set value when the external power supply of the LED drive circuit is powered down, when the resistance value of the sampling resistor unit is a second set value, the output current of the LED driving circuit is smaller than the output current when the resistance value of the sampling resistor unit is a first set value, and the energy storage element is used for supplying power to the LED driving circuit when an external power supply of the LED driving circuit is powered off.

Description

LED control circuit and LED lamp capable of realizing gradual darkening

Technical Field

The utility model belongs to the technical field of the LED, specifically relate to a realize gradually dark LED control circuit and LED lamp.

Background

LED lamps have been increasingly used in various places because of their advantages such as energy saving, long life, environmental protection, etc. The existing common LED lamp is dark instantly after being cut off by an external power supply, and under the bright state, the dark instantly can make people cannot adapt immediately, so that the user experience feeling is reduced.

However, most of the dim lamps in the market at present use a soft turn-off mode, that is, the lamps are powered all the time, when a user needs to turn off the lamps, a signal is triggered to the lamps, and the lamps are turned off in a gradual soft mode. The dim light function of this kind of mode will be realized, original circuit wiring and controlling means need be revised, trigger switch need be changed to the lamp body need use MCU or other logic control circuit to control, and is with high costs, and the circuit is complicated, realizes the degree of difficulty greatly, still has extravagant electric energy, comes the electric light after having a power failure and so on problem.

Disclosure of Invention

An object of the utility model is to provide a realize gradually dark LED control circuit and LED lamp with the technical problem who solves above-mentioned existence.

In order to achieve the above object, the utility model adopts the following technical scheme: the utility model provides a realize LED control circuit of gradual dark, including LED drive circuit, the output termination LED load of LED drive circuit, LED drive circuit has drive control IC, drive control IC's sampling termination has the sampling resistance unit, the resistance of sampling resistance unit is variable, have energy memory element in the LED drive circuit, still include quick power down detection circuit, quick power down detection circuit is configured to when the external power source of LED drive circuit loses electricity, control the resistance of sampling resistance unit and switch into the second setting value by first setting value, when the resistance of sampling resistance unit is the second setting value, the output current of LED drive circuit is less than the output current when the resistance of sampling resistance unit is first setting value, energy memory element is used for when the external power source of LED drive circuit loses electricity, for LED drive circuit power supply.

Furthermore, the sampling resistor unit comprises a first sampling resistor, a second sampling resistor and an MOS (metal oxide semiconductor) tube Q1, the first sampling resistor and the second sampling resistor are connected in parallel and then connected in series at the sampling end of the drive control IC, the MOS tube Q1 and the second sampling resistor are connected in series, and the grid of the MOS tube Q1 is connected with the output end of the rapid power failure detection circuit.

Furthermore, the resistance value of the first sampling resistor is larger than that of the second sampling resistor.

Furthermore, the fast power-down detection circuit comprises a first voltage division circuit, a capacitor C3, a second voltage division circuit and a triode Q2, wherein the first voltage division circuit is used for dividing the voltage of an external power supply of the LED driving circuit and then charging the capacitor C3 for driving the triode Q2, the triode Q2 is connected in the second voltage division circuit in series, and the second voltage division circuit is used for dividing the voltage of a working power supply of the LED driving circuit and then outputting the divided voltage to the grid of the MOS transistor Q1.

Furthermore, the triode Q2 is an NPN triode, the second voltage division circuit includes resistors R17 and R18, the resistors R17 and R18 are connected in series and then connected between the operating power supply of the LED driving circuit and ground, the triode Q2 is connected in series between the resistors R17 and R18, and a node between the triode Q2 and the resistor R18 is connected to a gate of the MOS transistor Q1.

Further, the first voltage division circuit comprises resistors R10, R11, R12, R13, R14 and R15, the resistors R10, R11, R14 and R15 are sequentially connected in series and then connected between a live wire of an external power supply of the LED driving circuit and the ground, the resistors R12, R13, R14 and R15 are sequentially connected in series and then connected between a zero line of the external power supply of the LED driving circuit and the ground, a node between the resistors R14 and R15 is connected with a base of a triode Q2, and the capacitor C3 and the resistor R15 are arranged in parallel.

Further, the energy storage element is a filter electrolytic capacitor of the LED driving circuit.

The utility model also discloses a LED lamp is equipped with foretell realization gradually dark LED control circuit.

The utility model has the advantages of:

the utility model uses the energy storage element as the source of gradually-darkening energy when being turned off, and is matched with the rapid power failure detection circuit to realize the gradually-darkening function, can be compatible with the traditional household lighting switch circuit, does not need to change a wiring circuit, can directly replace the prior lighting lamp, is physically turned off when being turned off, has no electric leakage phenomenon, has no problems of lighting the lamp by incoming electricity and the like, has simple structure, only needs to add some conventional electronic components, and has low cost; the circuit has the advantages of good compatibility, supporting the driving circuit with the energy storage element behind all rectifier bridges, and good realization effect.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

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

Detailed Description

To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The present invention will now be further described with reference to the accompanying drawings and detailed description.

As shown in fig. 1, an LED control circuit for realizing dimming includes an LED driving circuit 1, an output terminal P1 of the LED driving circuit 1 is connected to an LED load, the LED driving circuit 1 has a driving control IC U1, a sampling terminal CS of the driving control IC U1 is connected to a sampling resistor unit 2, a resistance value of the sampling resistor unit 2 is variable, the LED driving circuit 1 has an energy storage element therein, and further includes a fast power-down detection circuit 3, the fast power-down detection circuit 3 is configured to control a resistance value of the sampling resistor unit 2 to be rapidly switched from a first setting value to a second setting value when an external power supply of the LED driving circuit 1 is powered down, when the resistance value of the sampling resistor unit 2 is the second setting value, an output current of the LED driving circuit 1 is smaller than an output current when the resistance value of the sampling resistor unit 2 is the first setting value, the energy storage element is used when the external power supply of the LED driving circuit 1, the LED driving circuit 1 is continuously supplied with power.

In this embodiment, the LED driving circuit 1 is driven by a constant current, and includes a rectifying circuit, a filter circuit and a constant current driving circuit, the rectifying circuit is implemented by a rectifying bridge DB1, an input terminal of the rectifying circuit is connected to an external power supply (ac input), an output terminal of the rectifying circuit is connected to an input terminal of the constant current driving circuit through the filter circuit, and an output terminal P1 of the constant current driving circuit is connected to the LED load.

The constant current driving circuit may be a voltage boosting, voltage reducing, voltage boosting and reducing or linear driving circuit, and in this specific embodiment, the constant current driving circuit is a voltage reducing driving circuit, and includes an inductor T1, a diode D1, a driving control IC U1, and the like, the driving control IC U1 is an ac-dc low sampling resistance LED constant current driving IC, the filter circuit includes an inductor L1, a resistor R1, an electrolytic capacitor EC1, and an electrolytic capacitor EC2, and a specific circuit structure is shown in fig. 1 for details, which will not be described in detail.

In this embodiment, the sampling resistor unit 2 includes a first sampling resistor, a second sampling resistor and a MOS transistor Q1, the MOS transistor Q1 is an NMOS transistor, the first sampling resistor and the second sampling resistor are connected in parallel and then connected in series between the sampling terminal CS of the drive control IC and the ground, the MOS transistor Q1 is connected in series with the second sampling resistor, the gate of the MOS transistor Q1 is connected to the output terminal of the fast power-down detection circuit 3, and the MOS transistor Q1 is adopted, which has low energy consumption, high sensitivity and strong driving capability compared with other switching transistors, and certainly, in some embodiments, the MOS transistor Q1 may also be a PMOS transistor.

In this embodiment, the second sampling resistor is composed of resistors R6 and R8 connected in parallel, the first sampling resistor is composed of a resistor R7, and the resistance of the resistor R7 is greater than the resistances of the resistors R6 and R8, so that a better dimming effect can be achieved.

In this embodiment, the fast power-down detection circuit 3 includes a first voltage-dividing circuit, a capacitor C3, a second voltage-dividing circuit, and a transistor Q2, where the first voltage-dividing circuit is configured to divide an external power supply of the LED driving circuit 1 and then charge the capacitor C3, and is configured to drive the transistor Q2, the transistor Q2 is connected in series in the second voltage-dividing circuit, and the second voltage-dividing circuit is configured to divide a working power supply VCC of the LED driving circuit 1 and then output the divided working power supply VCC to a gate of the MOS transistor Q1. The rapid power failure detection circuit 3 adopts the triode Q2, the driving voltage is low, so that the capacitance value of the capacitor C3 can be selected to be small, when an external power supply fails, the electric quantity of the capacitor C3 can be discharged rapidly, the power failure detection speed is improved to reach about 2-3ms, the resistance value of the sampling resistor unit 2 is switched more rapidly, the electric energy consumption of the energy storage element is low, the sustainable delay time under the same energy storage element is longer, and the smoothing effect is better.

In this embodiment, the triode Q2 is an NPN triode, the second voltage division circuit includes resistors R17 and R18, the resistors R17 and R18 are connected in series and then connected between the operating power VCC (i.e., the operating power of the driving control IC U1) of the LED driving circuit 1 and the ground, the triode Q2 is connected in series between the resistors R17 and R18, the collector of the triode Q2 is connected to the resistor R17, the emitter of the triode Q2 is connected to the resistor R18, and the node (the output end of the fast power-down detection circuit 3) between the triode Q2 and the resistor R18 is connected to the gate of the MOS transistor Q1. Of course, in other embodiments, the transistor 2 may also be a PNP transistor

Further, the first voltage dividing circuit includes resistors R10, R11, R12, R13, R14 and R15, resistors R10, R11, R14 and R15 are sequentially connected in series and then connected between the live line L of the external power supply of the LED driving circuit 1 and the ground, resistors R12, R13, R14 and R15 are sequentially connected in series and then connected between the neutral line N of the external power supply of the LED driving circuit 1 and the ground, a node between the resistors R14 and R15 is connected to the base of the triode Q2, and the capacitor C3 and the resistor R15 are connected in parallel.

Preferably, in this embodiment, the energy storage element is a filter electrolytic capacitor in a filter circuit, and in this embodiment, the filter electrolytic capacitors EC1 and EC2 are used, and no energy storage element is required to be arranged, so that the compatibility is good, the structure is simple, the implementation is easy, and the cost is low.

The working process is as follows:

when the LED driving circuit is powered on, an external power source L and an external power source N respectively charge a capacitor C3 after current limiting and voltage division through resistors R10, R11, R12, R13, R14 and R15, a sinusoidal forward bias voltage exists at two ends of the capacitor C3, so that a triode Q2 is conducted, a resistor R17, the triode Q2 and a resistor R18 form a voltage division loop, the voltage division loop is conducted to have voltage division output, the grid of an MOS tube Q1 obtains voltage, the MOS tube Q1 is conducted, the resistances of the resistors R6 and R8 are smaller than that of the resistor R7, at the moment, the total sampling resistor at the CS end of the driving control IC U1 is about the resistor R6, the resistor R8 and the MOS tube Q1 conduct internal resistance (a first set value), the resistance is smaller, the driving control IC U1 controls the output current of the LED driving circuit 1 to be larger.

When the external power supply is powered off, a loop formed by the resistors R10, R11, R12, R13, R14 and R15 disappears, the electric energy of the capacitor C3 is quickly discharged by the resistor R15, the triode Q2 is cut off, a loop formed by the resistor R17, the triode Q2 and the resistor R18 disappears, and the MOS transistor Q1 is cut off. At this time, the sampling resistor at the CS end of the drive control IC U1 is a resistor R7 with a large resistance value, so that the output current of the drive control IC U1 for controlling the LED drive circuit 1 becomes small, the electric quantities of the electrolytic capacitors EC1 and EC2 continue to discharge small currents through the constant current drive circuit 1, the voltage held by the electrolytic capacitors EC1 and EC2 gradually decreases as the energy in the electrolytic capacitors EC1 and EC2 is used, the system working duty cycle increases, and when the maximum output duty cycle threshold of the drive control IC U1 is reached, the output current gradually decreases, a smooth dimming effect is achieved, until the drive control IC U1 stops working, the output is cut off, and the LED load is extinguished.

The utility model uses the energy storage element as the source of the gradually-darkening energy when being turned off, and is matched with the rapid power failure detection circuit to realize the gradually-darkening function, can be compatible with the traditional household lighting switch circuit, does not need to change a wiring circuit, can directly replace the prior lighting lamp, is physically turned off when being turned off, has no electric leakage phenomenon, has no problems of lighting lamps and the like when being turned off, has simple structure, only needs to add some conventional electronic devices, and has low cost; the circuit has the advantages of good compatibility, supporting the driving circuit with the energy storage element behind all rectifier bridges, and good realization effect.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The utility model provides a realize LED control circuit of gradual dark, includes LED drive circuit, LED drive circuit's output termination LED load, and LED drive circuit has drive control IC, and drive control IC's sampling end has connect sampling resistance unit, its characterized in that: the sampling resistor unit is variable in resistance value, the LED driving circuit is provided with an energy storage element, the LED driving circuit further comprises a rapid power-down detection circuit, the rapid power-down detection circuit is configured to control the resistance value of the sampling resistor unit to be switched from a first set value to a second set value when an external power supply of the LED driving circuit is powered down, when the resistance value of the sampling resistor unit is the second set value, the output current of the LED driving circuit is smaller than the output current when the resistance value of the sampling resistor unit is the first set value, and the energy storage element is used for supplying power to the LED driving circuit when the external power supply of the LED driving circuit is powered down.

2. The dimming-enabled LED control circuit of claim 1, wherein: the sampling resistor unit comprises a first sampling resistor, a second sampling resistor and an MOS (metal oxide semiconductor) tube Q1, the first sampling resistor and the second sampling resistor are connected in parallel and then connected in series on a sampling end of a drive control IC (integrated circuit), the MOS tube Q1 and the second sampling resistor are connected in series, and a grid electrode of the MOS tube Q1 is connected with an output end of the rapid power-down detection circuit.

3. The dimming-enabled LED control circuit of claim 2, wherein: the resistance value of the first sampling resistor is larger than that of the second sampling resistor.

4. The LED control circuit for realizing dimming according to claim 2 or 3, wherein: the quick power-down detection circuit comprises a first voltage division circuit, a capacitor C3, a second voltage division circuit and a triode Q2, wherein the first voltage division circuit is used for charging the capacitor C3 after dividing the voltage of an external power supply of the LED driving circuit and is used for driving the triode Q2, the triode Q2 is connected in the second voltage division circuit in series, and the second voltage division circuit is used for dividing the voltage of a working power supply of the LED driving circuit and outputting the divided voltage to the grid of an MOS tube Q1.

5. The dimming-enabled LED control circuit of claim 4, wherein: the triode Q2 is an NPN triode, the second voltage division circuit comprises a resistor R17 and a resistor R18, the resistor R17 and the resistor R18 are connected in series and then connected between a working power supply of the LED driving circuit and the ground, the triode Q2 is connected in series between the resistor R17 and the resistor R18, and a node between the triode Q2 and the resistor R18 is connected with a grid electrode of the MOS transistor Q1.

6. The dimming-enabled LED control circuit of claim 4, wherein: the first voltage division circuit comprises resistors R10, R11, R12, R13, R14 and R15, the resistors R10, R11, R14 and R15 are sequentially connected in series and then connected between a live wire and ground of an external power supply of the LED driving circuit, the resistors R12, R13, R14 and R15 are sequentially connected in series and then connected between a zero wire and ground of the external power supply of the LED driving circuit, a node between the resistors R14 and R15 is connected with a base electrode of a triode Q2, and the capacitor C3 and the resistor R15 are arranged in parallel.

7. The dimming-enabled LED control circuit of claim 1, wherein: the energy storage element is a filtering electrolytic capacitor of the LED driving circuit.

8. An LED lamp, characterized in that: an LED control circuit for realizing dimming according to any one of claims 1 to 7 is provided.