CN206674263U - A kind of Dimmable LED drive circuit of direct current supply - Google Patents

Abstract

The utility model discloses a kind of Dimmable LED drive circuit of direct current supply, including DC DC constant-current driven modules and dimming interface, the DC DC constant-current driven modules are connected with direct current DC inputs, and LED light source is driven for output constant current；The dimming interface is connected with the DC DC constant-current driven modules, for accessing intelligent illuminating system and controlling the DC DC constant-current driven modules accordingly to adjust output constant current value according to dimming commands.Using the technical solution of the utility model, due to using integrated LED chip NCL30160, it is only necessary to which seldom peripheral components are just embodied as LED light source and provide constant current, enormously simplify circuit structure while reduce the volume of LED drive circuit；NCL30160 has the input pin for being exclusively used in PWM light modulations simultaneously, it is possible to achieve the PWM light modulations of wide scope, conveniently accessible intelligent illuminating system.

Description

A kind of Dimmable LED drive circuit of direct current supply

Technical field

It the utility model is related to field of LED drive, more particularly to a kind of Dimmable LED drive circuit of direct current supply.

Background technology

At present, LED is semiconductor light-emitting elements, its characteristic determine direct current supply when LED it is more efficient, it is therefore, existing Many application scenario LED use direct current supply in technology.The dimming mode of LED drive power has simulation light modulation (Analog Dimming), bidirectional triode thyristor TRIAC is dimmed, the mode such as PWM light modulations (Pulse Width Modulation Dimming).Mould It is a kind of linearity light adjusting to intend light modulation.Simulation light modulation ratio can reach 50:1, typically 10:Less than 1.Simulating the shortcomings that dimming is The deviation of color is also easy to produce, because with current related, LED can be caused when the output current change of simulation light modulation for LED colourity There is deviation in color.The scope for simulating light modulation is narrower.Simulation light modulation can also influence the efficiency of LED power, so that system consumption is more More energy.What therefore simulation dimmed is of limited application.TRIAC light modulations are commonly used to exchange input, traditional illumination neck Domain is generally dimmed using bidirectional thyristor, is that input sinusoidal voltage is pruned into a part, is made the voltage for being input to power supply can not Sine wave is realized, therefore because substantial amounts of harmonic wave occurs in the imperfect of sine voltage, causes serious electromagnetic interference, together When, also result in the reduction of LED power efficiency and power factor (PF).And LED power, dimming effect are held using TRIAC light modulations Easily there is LED scintillation.PWM light modulations are to utilize square wave control signal ON/OFF LED constant current power supply, are put down to adjust LED light source The mode of equal brightness realizes light modulation.How the square-wave signal no matter dimmed changes, and LED is all the time in the bar of constant output current Lighted under part.It is haveing suffered in dimming scope, because LED output current converts between maximum and zero, by adjusting duty Than being in maximum and time in minimum value to adjust output current to change the average current of LED outputs, so PWM is adjusted The problem of misalignment is not present in light mode.With the rise of prior art illumination intelligent, PWM dimming modes can be more convenient Numerical control system is accessed, therefore, PWM light modulations have wider application.

Therefore for drawbacks described above present in currently available technology, it is necessary to be studied in fact, to provide a kind of scheme, Solves defect present in prior art.

Utility model content

In order to overcome the shortcomings of the prior art, drive electricity it is necessory to the Dimmable LED for providing a kind of direct current supply Road, the brightness adjustment control of LED drivings is realized with a kind of simple circuit structure, and intelligent photograph can be easily accessed by dimming interface Bright system.

In order to solve technical problem existing for prior art, the technical solution of the utility model is as follows：

A kind of Dimmable LED drive circuit of direct current supply, including DC-DC constant-current driven modules and dimming interface, it is described DC-DC constant-current driven modules are connected with direct current DC inputs, and LED light source is driven for output constant current；The dimming interface and institute State DC-DC constant-current driven modules to be connected, for accessing intelligent illuminating system and controlling the DC-DC constant currents according to dimming commands Drive module accordingly adjusts output constant current value；

The DC-DC constant-current driven modules include the first chip U1, first resistor R1, second resistance R2, the first electric capacity C1, Second electric capacity C2, the first inductance L1 and the first voltage-stabiliser tube Z1, wherein, the first chip U1 uses integrated LED control chip NCL30160；The negative terminal of the first voltage-stabiliser tube Z1 is connected with direct current DC input DC+ ends, the anode of the first voltage-stabiliser tube Z1 It is connected with one end of the first inductance L1 and the 8th pin of the first chip U1, the other end of the first inductance L1 It is connected with LED light source；The 7th pin of the first chip U1 is connected with one end of the second electric capacity C2；Described first Chip U1 the 6th pin is connected with the PWM control terminals of the dimming interface；The 5th pin of the first chip U1 and institute The one end for stating second resistance R2 is connected, fourth pin and institute of the other end of the second resistance R2 with the first chip U1 The one end for stating the first electric capacity C1 is connected, the other end of the first electric capacity C1, one end of the first resistor R1, described first Chip U1 the 3rd pin, the other end of the second electric capacity C2 are connected with GND ground terminals jointly；The first resistor R1's is another One end is connected with the first pin and second pin of the first chip U1.

Compared with prior art, using the technical solution of the utility model, due to using integrated LED chip NCL30160, it is only necessary to which seldom peripheral components are just embodied as LED light source and provide constant current, enormously simplify circuit structure simultaneously Reduce the volume of LED drive circuit；NCL30160 has the input pin for being exclusively used in PWM light modulations simultaneously, it is possible to achieve wide scope PWM light modulation, conveniently accessible intelligent illuminating system.

Brief description of the drawings

Fig. 1 is the structured flowchart of the Dimmable LED drive circuit of the utility model direct current supply.

Fig. 2 is the circuit theory diagrams of DC-DC constant-current driven modules in the utility model.

Specific examples below will further illustrate the utility model with reference to above-mentioned accompanying drawing.

Embodiment

Technical scheme provided by the utility model is described further below with reference to accompanying drawing.

Referring to Fig. 1, the structured flowchart of the Dimmable LED drive circuit of the utility model direct current supply, including DC- are shown DC constant-current driven modules and dimming interface, DC-DC constant-current driven modules are connected with direct current DC inputs, driven for output constant current LED light source；Dimming interface is connected with DC-DC constant-current driven modules, for accessing intelligent illuminating system and according to dimming commands Control DC-DC constant-current driven modules accordingly adjust output constant current value.Direct current DC inputs, DC-DC constant-current driven modules, dimming interface With LED light source common ground connection.

Referring to Fig. 2, the circuit theory diagrams of DC-DC constant-current driven modules in the utility model, DC-DC constant currents driving are shown Module further comprises the first chip U1, first resistor R1, second resistance R2, the first electric capacity C1, the second electric capacity C2, the first inductance L1 and the first voltage-stabiliser tube Z1, wherein, the first chip U1 uses integrated LED control chip NCL30160；First voltage-stabiliser tube Z1's is negative End is connected with direct current DC input DC+ ends, the first voltage-stabiliser tube Z1 anode and the first inductance L1 one end and the first chip U1 8th pin is connected, and the first inductance L1 other end is connected with LED light source；First chip U1 the 7th pin and the second electricity The one end for holding C2 is connected；First chip U1 the 6th pin is connected with the PWM control terminals of dimming interface；First chip U1's 5th pin is connected with second resistance R2 one end, the second resistance R2 other end and the first chip U1 the 4th pin and One electric capacity C1 one end is connected, and the first electric capacity C1 other end, first resistor R1 one end, the 3rd of the first chip U1 the draw Pin, the second electric capacity C2 other end are connected with GND ground terminals jointly；The first of the first resistor R1 other end and the first chip U1 Pin is connected with second pin.

In the utility model, DC-DC constant-current driven modules are realized using integrated LED control chip NCL30160. NCL30160 is a switching regulator for integrated LED, is carried so as to only need seldom peripheral components to be just embodied as LED light source For constant current, it enormously simplify circuit structure while reduce the volume of LED drive circuit.NCL30160 is internally integrated only 55 millis MOSFET inside the low conduction impedance in Europe (m Ω), the high switching frequency of 1.4 megahertzs of highest (MHz) make designer to use Smaller outer member, help to minimize circuit board size and cost minimizes.NCL30160 supports input voltage model Enclose has the input pin for being exclusively used in PWM light modulations for 6.3V to 40V, this control chip, it is possible to achieve the PWM light modulations of wide scope. Chip has the input pin of resistance programming adjustment constant current size.With short-circuit protection, under-voltage protection and overtemperature protection shutdown etc. are protected Protective function.And its peripheral circuit and its simple, it is only necessary to a small amount of several part cans driving LED light source, maximum output Electric current is 1A.

Fig. 2 is the complete circuit schematic diagram using NCL30160 chip drives LED light sources.1,2 pin CS is that current sense is anti- Feed pin, flow through the size of current of LED light source between CS pin and ground to set by connecting a resistance R1.NCL30160 is electricity Stream mode control, when internal FET is turned on, electric current passes through inductance and LED light source and FET from input, then arrives ground.Work as FET During shut-off, electric current is continuously through inductance and LED and diode.Output current control circuit is setting by CS comparator thresholds Put and provide 10% ripple current to realize.Peak point current comparator threshold is 220mV, is arranged to higher than average electric current 10%, and the threshold value of valley point current comparator is 180mV, is arranged to lower than average 10%.When FET is turned on, in inductance Electric current is risen by oblique wave.This electric current is detected by the non-essential resistance R1 between CS pin and ground.When the voltage of CS pin reaches During 220mV, peak point current comparator is by switch-off power FET.One traditional hysteresis controller continues to monitor load current, and When load current, which reduces, reaches 180mV until CS voltages, valley comparator is open-minded by FET.But when the fet is off, electric current Information can not obtain, therefore set the suitable FET turn-off times, and go to adjust by correction signal when FET is turned on herein Turn-off time is necessary.Short-circuit protection is also to be realized by CS comparators, the threshold for the CS comparators of short-circuit protection It is worth for 500mV, i.e. the 2.5 of average electric current times.It is more than normal export average electric current 2.5 times when CS pin detect short circuit current When, the CS comparators for short-circuit protection will turn off FET.Play the function of short-circuit protection.

The ROT pin of NCL30160 chips are off time setting resistance and connect pin.Outer meeting resistance be connected to ROT pin and The turn-off time of hysteresis controller is set between VCC pin.And in follow-up switch periods, when FET is turned on, CS pin detect Voltage, and when the fet is off, the amplitude adjuster threshold value according to CS voltage changes.

The DIM/EN pin of NCL30160 chips are PWM brightness adjustment controls or enabled pin.Connection one is logically high low level Pwm signal enables or closed power MOSFET and LED light source electric current to this pin.Make output current normal value and with It is lower to be changed according to dutycycle.So as to realize the regulation to LED luminance.PWM frequency necessarily be greater than more than 100Hz, otherwise LED light Scintillation occurs in source.But PWM frequency be not easy to it is too high, it is too high that EMI can be caused serious.In a kind of preferred embodiment In, 245Hz PWM frequency can be selected.

The LX pin of NCL30160 chips are that the drain electrode with internal power MOSEFET is connected.The first outside inductance L1 with LX pin are connected.First inductance L1 value determined in the course of work, the slope that output current is ramped up and declined.And inductance is electric The slope of stream determines that electric current needs the time how long from the valley of ripple to peak value when FET is turned on；And when FET ends When, electric current needs the time how long from the peak value of ripple current to valley.Higher inductance value reduce output current rise and The slope of decline, this causes the error between the ripple of actual output current and desired value to diminish.But the selection of inductance should make Export the saturation current value that peak current value is no more than electric current.Inductance value becomes big, after frequency reduces, and frequency reduces, MOSFET switching loss response can also reduce.So inductance value selection need consider, cost, volume and loss need Ask.

The explanation of above example is only intended to help and understands method and its core concept of the present utility model.It should refer to Go out, for those skilled in the art, can also be to this on the premise of the utility model principle is not departed from Utility model carries out some improvement and modification, and these are improved and modification also falls into the protection domain of the utility model claims It is interior.

The foregoing description of the disclosed embodiments, professional and technical personnel in the field are enable to realize or new using this practicality Type.A variety of modifications to these embodiments will be apparent for those skilled in the art, determine herein The General Principle of justice can be realized in other embodiments in the case where not departing from spirit or scope of the present utility model.Cause This, the utility model is not intended to be limited to the embodiments shown herein, and is to fit to and principles disclosed herein The most wide scope consistent with features of novelty.

Claims (1)

1. the Dimmable LED drive circuit of a kind of direct current supply, it is characterised in that including DC-DC constant-current driven modules and light modulation Interface, the DC-DC constant-current driven modules are connected with direct current DC inputs, and LED light source is driven for output constant current；The light modulation Interface is connected with the DC-DC constant-current driven modules, for accessing intelligent illuminating system and according to controlling dimming commands DC-DC constant-current driven modules accordingly adjust output constant current value；

The DC-DC constant-current driven modules include the first chip U1, first resistor R1, second resistance R2, the first electric capacity C1, second Electric capacity C2, the first inductance L1 and the first voltage-stabiliser tube Z1, wherein, the first chip U1 uses integrated LED control chip NCL30160；The negative terminal of the first voltage-stabiliser tube Z1 is connected with direct current DC input DC+ ends, the anode of the first voltage-stabiliser tube Z1 It is connected with one end of the first inductance L1 and the 8th pin of the first chip U1, the other end of the first inductance L1 It is connected with LED light source；The 7th pin of the first chip U1 is connected with one end of the second electric capacity C2；Described first Chip U1 the 6th pin is connected with the PWM control terminals of the dimming interface；The 5th pin of the first chip U1 and institute The one end for stating second resistance R2 is connected, fourth pin and institute of the other end of the second resistance R2 with the first chip U1 The one end for stating the first electric capacity C1 is connected, the other end of the first electric capacity C1, one end of the first resistor R1, described first Chip U1 the 3rd pin, the other end of the second electric capacity C2 are connected with GND ground terminals jointly；The first resistor R1's is another One end is connected with the first pin and second pin of the first chip U1.