CN208509320U

CN208509320U - LED drive circuit

Info

Publication number: CN208509320U
Application number: CN201820880220.1U
Authority: CN
Inventors: 刘拓夫; 周俊
Original assignee: On Bright Electronics Shanghai Co Ltd
Current assignee: Angbao Integrated Circuit Co ltd
Priority date: 2018-06-07
Filing date: 2018-06-07
Publication date: 2019-02-15
Anticipated expiration: 2028-06-07
Also published as: TWM569122U

Abstract

A kind of LED drive circuit, including exchange (AC) input rectification circuit, delay bright control circuit and output filter circuit, wherein: there are four rectification circuit terminals for AC input rectification circuit tool, first and second rectification circuit terminals are used to be separately connected the anode and cathode of AC power supplies, third rectification circuit terminal is connect with the first control circuit terminal for delaying bright control circuit, the 4th rectification circuit terminal ground；Delaying bright control circuit tool, there are four control circuit terminals, first control circuit terminal is connect with third rectification circuit terminal, second control circuit terminal connects benchmark, the connection of first filter circuit terminal of third control circuit terminal and output filter circuit, the second filter circuit terminal connect and ground of the 4th control circuit terminal and output filter circuit；There are two filter circuit terminal, the first and second filter circuit terminals are connect with the third and fourth control circuit terminal output filter circuit tool respectively, which is used to be separately connected the both ends of LED load.

Description

LED drive circuit

Technical field

The utility model relates to circuit fields, relate more specifically to a kind of LED driving electricity that can be realized LED and delay bright scheme Road.

Background technique

With the development of light emitting diode (LED) driver, LED delays bright scheme and is increasingly becoming one kind that people compare favor LED drive scheme.LED delays bright scheme and the difference of traditional LED drive scheme is, will not directly reach after LED unlatching Maximum brightness, but from low-light level gradual change to maximum brightness, with the adaptation time certain to human eye, protection people can be played in this way The effect of eye.

Current LED delays bright scheme and usually requires additional circuit (for example, micro-control unit (MCU)) to control LED's Brightness change, all without any advantage in cost and volume.It is therefore desirable to the LED of a kind of novel low cost, small size Delay bright scheme.

Utility model content

In view of above-described one or more problems, the utility model, which provides one kind and can be realized LED, delays bright scheme LED drive circuit.

According to the LED drive circuit of the utility model embodiment, including exchange (AC) input rectification circuit, delay bright control electricity Road and output filter circuit, in which: there are four rectification circuit terminal, the first and second rectified currents for AC input rectification circuit tool Road terminal is used to be separately connected the anode and cathode of AC power supplies, third rectification circuit terminal and the first control for delaying bright control circuit Circuit terminal connection, the 4th rectification circuit terminal ground；Delaying bright control circuit tool, there are four control circuit terminal, the first control electricity Road terminal is connect with third rectification circuit terminal, and second control circuit terminal connects benchmark, third control circuit terminal and output First filter circuit terminal of filter circuit connects, the second filtered electrical terminal of the 4th control circuit terminal and output filter circuit Sub- connect and ground；There are two filter circuit terminal, the first filter circuit terminal and third control circuits for output filter circuit tool Terminal connection, the second filter circuit terminal and the 4th control circuit terminal connect and ground, two filter circuit terminals are used for It is separately connected the both ends of LED load.

According to the LED drive circuit of the utility model embodiment, LED can be made not directly reach after unlatching most light Degree, but from low-light level gradual change to maximum brightness, and have the advantages that small size and low cost.

Detailed description of the invention

It may be better understood from the description with reference to the accompanying drawing to specific embodiment of the present utility model practical It is novel, in which:

Fig. 1 is the circuit diagram for showing the LED drive circuit according to the utility model embodiment.

Specific embodiment

Now, example embodiment will be described more fully hereinafter with reference to the accompanying drawings.However, example embodiment can be with a variety of shapes Formula is implemented, and is not understood as limited to embodiment set forth herein；On the contrary, thesing embodiments are provided so that this is practical new The design of example embodiment more comprehensively and completely, and is comprehensively communicated to those skilled in the art by type.In the figure in order to Clearly, it may be exaggerated the thickness of region and layer.Identical appended drawing reference indicates same or similar structure in figure, thus will Omit their detailed description.

In addition, described feature, structure or characteristic can be incorporated in one or more implementations in any suitable manner In example.In the following description, many details are provided to provide and fully understand to the embodiments of the present invention.So And it will be appreciated by persons skilled in the art that the technical solution of the utility model can be practiced without in the specific detail It is one or more, or can be using other methods, constituent element, material etc..In other cases, it is not shown in detail or describes public affairs Know structure, material or operation to avoid the major technique intention of fuzzy the utility model.

Fig. 1 is the circuit diagram for showing the LED drive circuit according to the utility model embodiment.As shown in Figure 1, according to this reality It is the LED drive circuit based on BUCK circuit structure with the LED drive circuit of new embodiment, and is inputted including exchange (AC) Rectification circuit 102 delays bright control circuit 104 and output filter circuit 106, in which:

There are four rectification circuit terminals for the tool of AC input rectification circuit 102, and the first and second rectification circuit terminals are for distinguishing The anode and cathode of AC power supplies are connected, third rectification circuit terminal connects with the first control circuit terminal for delaying bright control circuit 104 It connects, the 4th rectification circuit terminal ground.

Delaying the bright tool of control circuit 104, there are four control circuit terminal, first control circuit terminal and AC input rectification circuits 102 third rectification circuit terminal connection, second control circuit terminal connect benchmark, and third control circuit terminal and output filter First filter circuit terminal of circuit 106 connects, the second filter circuit of the 4th control circuit terminal and output filter circuit 106 Terminal connect and ground.

The tool of output filter circuit 106 first filter circuit terminal and delays bright control circuit 104 there are two filter circuit terminal Third control circuit terminal connection, the second filter circuit terminal with delay bright control circuit 104 the 4th control circuit terminal connect It connects and is grounded.Here, two filter circuit terminals of output filter circuit 106 are used to be separately connected the both ends of LED load.

In some embodiments, AC input rectification circuit 102 includes fuse F1, rectifier diode D1, D2, D3, D4, with And input filter capacitor C1.Delaying bright control circuit 104 includes delaying bright control chip U1, high voltage startup resistance R1, current detecting electricity R2 is hindered, resistance R3 and R4 is arranged in demagnetization detection and open-circuit-protection, and chip power supply capacitor C2 delays bright time control capacitor C3, afterflow Diode D5 and power inductance L1.Output filter circuit 106 includes output filter capacitor C4.

In some embodiments, delay drain electrode foot (DRAIN foot) that bright control chip U1 includes chip interior high-voltage MOS pipe, Bright time setting is delayed in chip power supply foot (VDD foot), demagnetization detection and open-circuit-protection foot (FB foot), LED current setting foot (CS foot) Foot (FT foot) and chip reference ground (GND foot).Here, delay it is bright control chip U1 GND foot can with delay bright control circuit 104 second control circuit terminal connects or as the second control circuit terminal for delaying bright control circuit 104.

Specifically, the course of work for delaying bright control chip U1 is as follows:

First stage is after the power-up rushed the output voltage of LED drive circuit in advance to the electricity for being slightly less than LED conducting voltage Pressure.

Second stage charges to bright control capacitor C3 is delayed, so that the voltage delayed on bright control capacitor C3 increases at any time；It is logical It crosses detection and delays the voltage on bright control capacitor C3 to control the size of the output electric current of LED drive circuit, so that LED drive circuit Output electric current size with delay it is bright control capacitor C3 on voltage raising and increase, to realize that LED's delays bright control.This In, the capacitance size for delaying bright control capacitor C3 determines that LED delays the length of time of bright process.

Phase III charges to certain voltage and keeps, so that the brightness of LED reaches most light to bright control capacitor C3 is delayed It spends and keeps the maximum brightness.

The utility model can be realized in other specific forms, without departing from its spirit and essential characteristics.Therefore, currently Embodiment should all be counted as being exemplary rather than in all respects limited, the scope of the utility model is by appended power Benefit requires rather than foregoing description defines, also, fall into the meaning of claim and whole in the range of equivalent change all by It is included among the scope of the utility model.

Claims

1. An LED drive circuit, comprising an alternating current (AC) input rectifier circuit, a slow-brightness control circuit, and an output filter circuit, wherein:

The AC input rectifier circuit has four rectifier circuit terminals, the first and second rectifier circuit terminals are used to connect the positive and negative poles of the AC power supply respectively, and the third rectifier circuit terminal is connected to the first control circuit terminal of the slow-brightening control circuit connected, the fourth rectifier circuit terminal is grounded;

The slow-brightening control circuit has four control circuit terminals, the first control circuit terminal is connected to the third rectifier circuit terminal, the second control circuit terminal is connected to the reference ground, and the third control circuit terminal is connected to the output filter circuit The first filter circuit terminal of the output filter circuit is connected, and the fourth control circuit terminal is connected to the second filter circuit terminal of the output filter circuit and grounded;

The output filter circuit has two filter circuit terminals, the first filter circuit terminal is connected to the third control circuit terminal, the second filter circuit terminal is connected to the fourth control circuit terminal and grounded, and the Two filter circuit terminals are used to connect two ends of the LED load respectively.

2. The LED driving circuit of claim 1, wherein the AC input rectifier circuit comprises a fuse, a rectifier diode, and an input filter capacitor.

3. The LED driving circuit of claim 1, wherein the slow-brightness control circuit comprises a slow-brightness control chip, a high-voltage startup resistor, a current detection resistor, a demagnetization detection and an open-circuit protection setting resistor, a chip power supply capacitor, and a slow-brightness time. Control capacitors, freewheeling diodes, and power inductors.

4. The LED driving circuit of claim 1, wherein the output filter circuit comprises an output filter capacitor.

5. The LED driving circuit of claim 3, wherein the slow-brightening control chip comprises the following pins: a drain pin of a high-voltage MOS tube inside the chip, a chip power supply pin, a demagnetization detection and open circuit protection pin, an LED current setting pin Fixed foot, slow lighting time setting foot, and chip reference ground.

6 . The LED driving circuit of claim 3 , wherein the slow-brightness control chip charges the slow-brightness control capacitor, so that the voltage on the slow-brightness control capacitor increases with time, and by detecting the The voltage on the slow-brightness control capacitor is used to control the magnitude of the output current of the LED drive circuit, so that the magnitude of the output current of the LED drive circuit increases with the increase of the voltage on the slow-brightness control capacitor, so as to achieve Slow-bright control of the LED load.