LED driver
Technical field
The utility model relates to LED and drives field, particularly a kind of LED driver of electric current stable output.
Background technology
LED illumination is a kind of new type light source of rapid rising development in recent years, and its many good feature makes its application surface more and more wider.The unilateal conduction characteristic of LED makes LED must be equipped with LED driver could to work, in existing LED drive circuit, particularly when electric main driving LED lamp, LED drive circuit must have current rectifying and wave filtering circuit, current rectifying and wave filtering circuit needs relatively large capacitance rectifier output voltage could be smoothed to allowed band, therefore there is use electrolytic capacitor in existing LED drive circuit, the advantage of electrolytic capacitor maximum is good economy performance, affect the useful life of drive circuit the useful life of electrochemical capacitor, and the life-span of electrochemical capacitor is depended on the temperature that it is inner, temperature rise is the factor that electrochemical capacitor working life is had the greatest impact, therefore, the impact in the useful life of the radiating effect of drive enclosure on drive circuit is very large.
And the temperature coefficient of the P-N of LED knot is for negative, when temperature raises, the potential barrier electromotive force of LED reduces.Therefore, LED can not directly use voltage fed, must adopt the drive circuit with current-limiting function, otherwise the rising of temperature while working along with LED, electric current can be increasing, so that damage LED.The ratio that simultaneously flows through the electric current of LED and the luminous flux of LED is also nonlinear.The luminous flux of LED increases and increases along with flowing through the electric current of LED, but is not directly proportional, and luminous flux increases lesser more finally.Therefore, should make LED work under the higher fixed current value of luminous efficiency.
Summary of the invention
Main purpose of the present utility model is to provide a kind of LED driver, is intended to improve the radiating effect of drive enclosure, extends the useful life of LED driver; Realize output circuit current stabilization, for LED provides stable electric current, prevent that LED is burned, the brightness that realizes LED demonstration is even, stable.
The utility model proposes a kind of LED driver, comprise shell and be placed in the LED drive circuit plate in described shell, described shell is made up of heating panel and housing, described heating panel and described shell are made by metal material that can heat conduction, the cross section of described heating panel is " work " type, described LED drive circuit plate laminating is fixed on the lower surface of described heating panel, on the upper surface of described heating panel, be provided with some fin, described fin is column to be arranged, and between described fin is adjacent, interval forms ventilation slot; The shape of described housing and described heating panel adaptation, described housing is wrapped in outside described heating panel, and position corresponding with described fin on described housing has port.
Preferably, on the sidewall of described housing, be provided with some vent ribs.
Preferably, the two ends of described housing are opening setting, are provided with adaptive end cap at described opening part, on described end cap, are provided with wire through-hole.
Preferably, described LED drive circuit plate is provided with the input protection circuit, reduction voltage circuit, current rectifying and wave filtering circuit, current regulator diode and the LED light source circuit that are electrically connected successively, described current rectifying and wave filtering circuit comprises bridge rectifier and filter capacitor, and described filter capacitor is in parallel with the output of described bridge rectifier; Described LED light source circuit comprises at least one group of light source group, and described in each, light source group is connected with current regulator diode described in, parallel with one another between multiple described light source groups.
Preferably, described input protection circuit is made up of a fuse.
Preferably, described reduction voltage circuit is made up of decompression capacitor and the first bleeder resistance, and described the first bleeder resistance is connected in parallel on the two ends of described decompression capacitor.
Preferably, described bridge rectifier is single phase bridge type rectifier circu, is made up of four diodes.
Preferably, also comprise second bleeder resistance in parallel with described filter capacitor.
Preferably, described light source group comprises one or more LED luminous elements, series connection mutually between the LED luminous element in same described light source group.
The shell of LED driver of the present utility model is made up of heating panel and housing, and heating panel and shell all adopt metal material that can heat conduction to make, and have good thermal conductivity.The cross section of heating panel is " work " type, the laminating of LED drive circuit plate is fixed on the lower surface of heating panel, on the upper surface of heating panel, be provided with some fin, the heat on LED drive circuit plate conducts to heating panel and fin, by heating panel and fin quick heat radiating; Fin is column to be arranged, and between fin is adjacent, interval forms ventilation slot, can accelerate circulation of air, improves radiating effect, thereby can prevent that LED drive circuit plate from distributing not go out and cause temperature rise because of the temperature that work produces, and extends the useful life of LED driver.The shape of housing and heating panel adaptation, housing is wrapped in outside heating panel, can protect LED drive circuit plate, prevents the impact on LED drive circuit plate such as rainwater, dust; Position corresponding with fin on housing has port, can guarantee that fin fully contacts with air, makes fin quick heat radiating.
The LED drive circuit plate of LED driver of the present utility model is provided with the input protection circuit, reduction voltage circuit, current rectifying and wave filtering circuit, current regulator diode and the LED light source circuit that are electrically connected successively, current rectifying and wave filtering circuit comprises bridge rectifier and filter capacitor, filter capacitor is in parallel with the output of bridge rectifier, LED driver external AC, High Level AC Voltage is through reduction voltage circuit step-down, then the direct voltage of unidirectional pulsation is exported in bridge rectifier rectification in current rectifying and wave filtering circuit; Filter capacitor is used for the alternating component in unidirectional pulsating voltage after filtering rectification, makes it to become level and smooth direct voltage; LED light source circuit comprises at least one group of light source group, each light source group is connected with a current regulator diode, current regulator diode can be exported constant electric current in very wide voltage range, and there is very high motional impedance, therefore in circuit, occurring that supply voltage is supplied when unstable all can guarantee that circuital current is stable, for light source group provides stable electric current, LED luminous element under driving, stable voltage and current is worked, prevent that LED luminous element is burned, the luminosity of realizing LED luminous element evenly, stable, without dodging screen.
Brief description of the drawings
Fig. 1, Fig. 2 and Fig. 3 are the stereogram of LED driver shell in the embodiment of LED driver of the present utility model;
Fig. 4 is the circuit diagram of LED drive circuit plate in the embodiment of LED driver of the present utility model;
Realization, functional characteristics and the advantage of the utility model object, in connection with embodiment, are described further with reference to accompanying drawing.
Embodiment
Should be appreciated that specific embodiment described herein is only in order to explain the utility model, and be not used in restriction the utility model.
Referring to figs. 1 through Fig. 4, one embodiment of LED driver of the present utility model is proposed, this LED driver comprises shell 10 and is placed in the LED drive circuit plate in shell 10, shell 10 is made up of heating panel 11 and housing 12, heating panel 11 and housing 12, by can the die casting of heat conduction aluminum alloy material forming, have good heat conductivility.The cross section of heating panel 11 is " work " type, the laminating of LED drive circuit plate is fixed on the lower surface of heating panel 11, on the upper surface of heating panel 11, be provided with some fin 110, heat on LED drive circuit plate conducts to heating panel 11 and fin 110, by heating panel 11 and fin 110 quick heat radiatings.Fin 110 is column and arranges, between fin 110 is adjacent, interval forms ventilation slot 111, can accelerate circulation of air, improves radiating effect, thereby can prevent that LED drive circuit plate from distributing not go out and cause temperature rise because of the temperature that work produces, and extends the useful life of LED driver.
The shape of housing 12 and heating panel 11 adaptations, housing 12 is wrapped in outside heating panel 11, can protect LED drive circuit plate, prevents the impact on LED drive circuit plate such as rainwater, dust; Housing 12 has thermal conductivity simultaneously, can auxiliary heat dissipation.Position corresponding with fin 110 on housing 12 has port, can guarantee that fin 110 fully contacts with air, makes fin 110 quick heat radiatings.
On the sidewall of housing 12, be provided with some vent ribs 120, vent rib 120 can improve the contact area of housing 12 and extraneous air, thereby improves radiating rate.
The two ends of housing 12 are opening setting, are provided with adaptive end cap 13 at opening part, on end cap 13, are provided with wire through-hole, stretch from through hole, two ends with the wire that LED drive circuit plate is electrically connected.
LED drive circuit plate is provided with the input protection circuit, reduction voltage circuit 1, current rectifying and wave filtering circuit 2, current regulator diode D5 and the LED light source circuit 3 that are electrically connected successively.Alternating current input is connected with input protection circuit; this input protection circuit is made up of a fuse F; the effect of fuse F is to provide circuit safety protection; the in the situation that of short circuit or serious overload; fuse F automatically fusing disconnects circuit, thereby realizes short-circuit protection or serious overload protection.
The input of reduction voltage circuit 1 is connected with the output of input protection circuit, for the High Level AC Voltage of input is carried out to step-down.Reduction voltage circuit 1 is made up of decompression capacitor C1 and the first bleeder resistance R1, and decompression capacitor C1 can produce capacitive reactance under certain AC signal frequency, thereby the maximum operating currenbt of restriction LED driver is realized current limliting step-down.The first bleeder resistance R1 is connected in parallel on the two ends of decompression capacitor C1, for the path of releasing being provided to decompression capacitor C1, so that after decompression capacitor C1 quits work, and the electric energy of the decompression capacitor C1 two ends storage of releasing.
The input of current rectifying and wave filtering circuit 2 is connected with the output of reduction voltage circuit 1, and reduction voltage circuit 1 carries out High Level AC Voltage to export to current rectifying and wave filtering circuit 2 after step-down, carries out rectifying and wave-filtering by current rectifying and wave filtering circuit 2.Current rectifying and wave filtering circuit 2 comprises bridge rectifier, filter capacitor C2 and a second bleeder resistance R2 in parallel with described filter capacitor C2, bridge rectifier is single phase bridge type rectifier circu, formed by four diode D1, D2, D3, D4, for the direct voltage that is unidirectional pulsation by AC voltage conversion; Filter capacitor C2 is in parallel with the output of bridge rectifier, for the alternating component of the unidirectional pulsating dc voltage after filtering rectification, makes it to become level and smooth direct voltage.The second bleeder resistance R2 provides the path of releasing to filter capacitor C2, so that after filter capacitor C2 quits work, and the electric energy of its two ends storage of releasing.
LED light source circuit 3 is connected with the output of current rectifying and wave filtering circuit 2, the LED luminous element work in the direct voltage drive LED light source circuit 3 that current rectifying and wave filtering circuit 2 is exported.LED light source circuit 3 comprises at least one group of light source group, and light source group can arrange one or more groups, parallel with one another between multiple light source groups, and each light source group is connected with a current regulator diode D5.Light source group comprises one or more LED luminous elements, series connection mutually between the LED luminous element in same light source group.In the present embodiment, be provided with one group of light source group, the direct current of alternating current output smoothing after current rectifying and wave filtering circuit 2 rectifying and wave-filterings of input, direct current is through current regulator diode D5, current regulator diode D5 can export constant electric current in very wide voltage range, and there is very high motional impedance, therefore in circuit, occurring that supply voltage is supplied when unstable all can guarantee that circuital current is stable, for light source group provides stable electric current, LED luminous element under driving, stable voltage and current is worked, prevent that LED luminous element is burned, the luminosity of realizing LED luminous element is even, stable, without dodging screen, for user provides illumination.
The foregoing is only preferred embodiment of the present utility model; not thereby limit the scope of the claims of the present utility model; every equivalent structure transformation that utilizes the utility model specification and accompanying drawing content to do; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present utility model.