CN214799979U - LED silicon controlled rectifier power supply circuit of adjusting luminance - Google Patents

Abstract

The utility model discloses a LED silicon controlled rectifier dimming power circuit, which comprises an EMC circuit unit, a rectifying and filtering unit, a flyback transformer unit, a PWM controller unit, a rectifying and filtering output unit and a ripple removing unit; the EMC circuit unit is connected with the rectification filter unit, and the rectification filter unit is respectively connected with the flyback transformer unit and the PWM controller unit; the flyback transformer unit is respectively connected with the PWM controller unit and the rectification filter output unit; the rectification filtering unit is connected with the ripple wave removing unit; when the second transformer is in a positive half period, the second transformer is superposed with the voltage charged in the negative half period of the twelfth capacitor through the rectification of a fifth and a thirteenth resistors and a twenty-fifth diode to charge the thirteenth capacitor, so that the voltage of the thirteenth capacitor is boosted, the voltage of the thirteenth capacitor is higher than that of the LED +, and the third MOS transistor is half-turned on; when the ripple waves are superposed on the direct current, the voltage of the LED + rises, and the grid voltage of the third MOS tube is fixed, so that the voltage of the source electrode of the third MOS tube is reduced, the internal resistance of the third MOS tube is increased, and the topping and ripple wave removal are realized.

Description

LED silicon controlled rectifier power supply circuit of adjusting luminance

Technical Field

The utility model relates to a LED power field especially relates to a LED silicon controlled rectifier power supply circuit that adjusts luminance.

Background

In recent years, with the rise of the global LED commercial lighting market, many LED manufacturers including china place LED commercial lighting products at an important position for market development. The major markets of Europe and America and the like put forward the requirements on LED lighting products in the aspects of high efficiency, long service life, high power factor, flexible expansion, dimmable and the like, so that the LED driving IC and power supply industry faces a new revolution. Therefore, the application proportion of intelligent dimming of the silicon controlled dimming power supply, especially in commercial illumination, is expected to be rapidly increased.

Compared with the traditional lighting mode, the LED lighting not only improves the high quality of light, improves the light source efficiency and prolongs the service life of the lamp, but also can adjust the brightness and the color temperature of the lamp by the silicon controlled rectifier dimming function, thereby creating the light environment and energy-saving application; at present, the market has a large demand on dimming power supply products, and most of the dimming power supply products are used together with a silicon controlled rectifier dimmer. Therefore, the research on the LED lighting product with the silicon controlled rectifier dimming is significant.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the defects existing in the prior art and providing a LED silicon controlled rectifier dimming power circuit.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

an LED silicon controlled rectifier dimming power supply circuit is characterized by comprising an EMC circuit unit, a rectifying and filtering unit, a flyback and voltage transformation unit, a PWM controller, a rectifying and filtering output unit and a ripple removing unit; the EMC circuit unit is connected with the rectifying and filtering unit, and the rectifying and filtering unit is respectively connected with the flyback transformer unit and the PWM controller; the flyback transformer unit is respectively connected with the PWM controller and the rectification filter output unit; the rectification filtering unit is connected with the ripple removing unit.

Preferably, the EMC circuit unit includes a first transformer, a fourth transformer, a first inductance, and a second inductance; one end of the first transformer is connected with an external power supply, and the other end of the first transformer is connected with the fourth transformer through the first inductor and the second inductor respectively; and the two ends of the first inductor are connected with a fifth resistor, and the two ends of the second inductor are connected with a sixth resistor.

Preferably, the rectifying and filtering unit includes a rectifying diode, a first MOS transistor, and a third inductor; the rectifier diode is connected with the fourth transformer, and the anode of the rectifier diode is connected with the third inductor; the source electrode of the first MOS tube is connected with the cathode of the rectifier diode and grounded, the grid electrode of the first MOS tube is connected with the cathode of the rectifier diode and grounded sequentially through a thirteenth resistor and a seventeenth capacitor, and the drain electrode of the first MOS tube is connected with one end of the third inductor through an eighteenth capacitor; the other end of the third inductor is connected with the cathode of the rectifier diode through a twenty-fifth resistor and the first capacitor in sequence and is grounded.

Preferably, the flyback transformer unit includes a second MOS transistor, a second transformer, a fifth transformer, and a third schottky diode; one end of the second transformer is connected with the third inductor, and the other end of the second transformer is connected with the fifth transformer through a seventh capacitor; the drain electrode of the second MOS tube is respectively connected with the second transformer and the positive electrode of the seventh diode, and the grid electrode of the second MOS tube is connected with the third Schottky diode through an eleventh resistor and grounded; the source electrode of the second MOS tube is connected with the negative electrode of a ninth diode, and the positive electrode of the ninth diode is connected between the eleventh resistor and the third Schottky diode; one end of the second transformer is grounded through an eighth resistor, a tenth resistor, a thirteenth resistor and a fourteenth capacitor in sequence, and one end of the fourteenth capacitor is connected between the eleventh resistor and the cathode of the third Schottky diode.

Preferably, the PWM controller unit includes a transistor and a PWM controller; the second pin of the PWM controller is connected with the collector of the triode through a twenty-ninth resistor; the third inductor is grounded through a sixth diode, a thirty-third resistor, a thirty-second resistor and a thirty-first resistor in sequence; the base electrode of the triode is connected between the thirty-first resistor and the thirty-second resistor through a thirty-second resistor, and the emitter electrode of the triode is respectively connected with one end of a third capacitor and one end of a fourth capacitor and grounded; the other end of the third capacitor is connected between the sixth diode and the thirty-third resistor, and the other end of the fourth capacitor is connected with the collector of the triode through a twenty-ninth resistor.

Preferably, a third pin of the PWM controller is connected to the fifth transformer through a fifteenth resistor and a fourteenth resistor; a fourth pin of the PWM controller is connected with the fifth transformer through a twelfth diode and a thirty-ninth resistor, and the fourth pin of the PWM controller is grounded through the twelfth resistor and the second Schottky diode in sequence; a fifth pin of the PWM controller is connected with the first MOS tube through a twenty-third resistor; a ninth pin of the PWM controller is connected with a source electrode of the second MOS tube; the eleventh pin of the PWM controller is connected with a thermistor through a seventeenth resistor and is grounded; and a thirteenth pin of the PWM controller is respectively connected with a ninth resistor and a thirty-fourth capacitor.

Preferably, the rectifying and filtering output unit includes a third transformer, a third MOS transistor, and a thirteenth diode; the drain electrode of the third MOS tube is connected with the second transformer through the thirteenth diode, and the source electrode of the third MOS tube is connected with one end of the third transformer; one end of the third transformer is connected with the second transformer, and the other end of the third transformer is connected with the LED lamp.

Preferably, the ripple removing unit includes a twenty-first diode, a twenty-second diode, a twenty-fifth diode, a thirteenth capacitor and a fifty-third resistor; the twenty-first diode and the twenty-second diode are connected in series, and the anode of the twenty-second diode is connected with the thirteenth capacitor; the twenty-fifth diode and the fifty-third resistor are connected in series; the second transformer is grounded through a twelfth capacitor, a fifty-fourth resistor and a twenty-third diode in sequence, and the fifty-third resistor is connected between the twelfth capacitor and the fifty-fourth resistor; the drain electrode of the third MOS tube is respectively connected with a fifty-th resistor and the twenty-first diode, and the fifty-th resistor is connected with the thirteenth capacitor through a fifty-first resistor and grounded; the grid electrode of the third MOS tube is grounded through a fifth-twelfth resistor and the thirteenth capacitor in sequence, and the source electrode of the third MOS tube is connected with the fifty-second resistor through a twenty-sixth diode and a twenty-fourth diode in sequence.

Compared with the prior art, the beneficial effects of the utility model are that:

the utility model relates to a LED silicon controlled rectifier power supply circuit of adjusting luminance, during the Ton of second MOS pipe switch-on, input power Ui adds power to second transformer primary coil N1 winding, N1 winding has electric current i1 to flow through, both ends produce self-induced electromotive force, the both ends of N2 winding also produce induced electromotive force simultaneously, nevertheless because rectifier diode's effect, do not produce return circuit current, be equivalent to opening a way, the second transformer be equivalent with an energy storage inductance. At the moment when the control switch is switched from on to off suddenly, the current i1 flowing through the primary coil of the second transformer is 0 suddenly, and the magnetic flux cannot be suddenly changed, so that during the Toff period when the second MOS tube is switched off, the magnetic flux in the iron core of the second transformer is mainly maintained by the current in the coil loop of the N2, and the flyback current is generated in the N2 to supply power; during the negative half period of the second transformer, the twelfth capacitor is charged through a thirteenth diode and a fifty-fourth resistor; when the second transformer is in a positive half period, the second transformer is rectified by a fifth and thirteenth resistor and a twenty-fifth diode and is superposed with the voltage charged in the negative half period of the twelfth capacitor, the thirteenth capacitor is charged to realize boosting, the voltage of the thirteenth capacitor is higher than that of the LED +, and the third MOS transistor is turned on in a half-on mode; when the ripple waves are superposed on the direct current, the voltage of the LED + rises, and the grid voltage of the third MOS tube is fixed, so that the voltage of the source electrode of the third MOS tube is reduced, the internal resistance of the third MOS tube is increased, and the topping and ripple wave removal are realized.

Drawings

Fig. 1 is a schematic view of the present invention;

fig. 2 is a schematic circuit diagram proposed by the present invention;

fig. 3 is a schematic circuit diagram of an embodiment of the present invention;

fig. 4 is a schematic circuit diagram of another embodiment of the present invention.

Illustration of the drawings:

1. an EMC circuit unit, 2, a rectifying and filtering unit,

3. a flyback transformer unit, 4, a PWM controller unit,

5. and the rectification filtering output unit 6 is a ripple removing unit.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention; the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, as they may be fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1 to 4, an LED silicon controlled rectifier dimming power supply circuit includes an EMC circuit unit 1, a rectifying and filtering unit 2, a flyback transformer unit 3, a PWM controller unit 4, a rectifying and filtering output unit 5, and a ripple removing unit 6; the EMC circuit unit 1 is connected with the rectifying and filtering unit 2, and the rectifying and filtering unit 2 is respectively connected with the flyback transformer unit 3 and the PWM controller unit 4; the flyback transformer unit 3 is respectively connected with the PWM controller unit 4 and the rectification filter output unit 5; the rectifying and filtering unit 5 is connected with the ripple removing unit 6.

The EMC circuit unit 1 includes a first transformer T1, a fourth transformer T4, a first inductance L1, and a second inductance L2; one end of a first transformer T1 is connected with an external power supply, and the other end of the first transformer T1 is connected with a fourth transformer T4 through a first inductor L1 and a second inductor L2 respectively; a fifth resistor R5 is connected to two ends of the first inductor L1, and a sixth resistor R6 is connected to two ends of the second inductor L2; the third resistor R3 and the fourth resistor R4 are connected in series, one end of the third resistor R3 is connected between the first inductor L1 and the fourth transformer T4, and one end of the fourth resistor R4 is connected between the second inductor L2 and the fourth transformer T4; the third capacitor C3 is connected in parallel with the third resistor R3 and the fourth resistor R4.

The rectifying and filtering unit 2 comprises a rectifying diode DB1, a first MOS tube Q1 and a third inductor L3; the rectifier diode DB1 is connected to the fourth transformer T4, and the anode of the rectifier diode DB1 is connected to the third inductor L3; the source of the first MOS transistor Q1 is connected with the cathode of the rectifier diode DB1 and grounded, the gate of the first MOS transistor Q1 is connected with the cathode of the rectifier diode DB1 through a thirteenth resistor R23 and a seventeenth capacitor C17 in sequence and grounded, and the drain of the first MOS transistor Q1 is connected with one end of a third inductor L3 through an eighteenth capacitor C18; the eighteenth capacitor C18 is grounded through a twenty-second resistor R22, a sixteenth capacitor C16 is connected to the two ends of the eighteenth capacitor C18, and a twenty-first resistor R21 is connected to the two ends of the twenty-second resistor R22; the other end of the third inductor L3 is connected with the negative electrode of the rectifier diode DB1 through a twenty-fifth resistor R25 and a first capacitor C1 in sequence and grounded, and two ends of the twenty-fifth resistor R25 are connected with a twenty-fourth resistor R24.

The flyback transformer unit 3 includes a second MOS transistor Q2, a second transformer T2, a fifth transformer T5, and a third schottky diode ZD 3; one end of a second transformer T2 is connected with a third inductor L3, and the other end of the second transformer T2 is connected with a fifth transformer T5 through a seventh capacitor C7; the drain of the second MOS transistor Q2 is connected to the anodes of the second transformer T2 and the seventh diode D7, respectively, the gate of the second MOS transistor Q2 is connected to the third schottky diode ZD3 through an eleventh resistor R11 and grounded, and the two ends of the eleventh resistor R11 are connected to an eighth diode D8; the source of the second MOS transistor Q2 is connected to the cathode of the ninth diode D9, and the anode of the ninth diode D9 is connected between the eleventh resistor R11 and the third schottky diode ZD 3; one end of a second transformer T2 is grounded through an eighth resistor R8, a tenth resistor R10, a thirteenth resistor R13 and a fourteenth capacitor C14 in sequence, and one end of a fourteenth capacitor C14 is connected between an eleventh resistor R11 and the cathode of a third Schottky diode ZD 3; one end of a second transformer T2 is respectively connected with a thirty-sixth resistor R36, a thirty-seventh resistor R37, a thirty-eighth resistor R38 and a fifteenth capacitor C15, the cathode of a seventh diode D7 is respectively connected with a forty-fourth resistor R44 and a forty-fifth resistor R45, and the thirty-sixth resistor R36, the thirty-seventh resistor R37, the thirty-eighth resistor R38 and the fifteenth capacitor C15 are respectively connected with a forty-fourth resistor R44 and a forty-fifth resistor R45; the thirty-sixth resistor R36, the thirty-seventh resistor R37, the thirty-eighth resistor R38 and the fifteenth capacitor C15 are connected in parallel.

The PWM controller unit 4 includes a transistor Q5 and a PWM controller U1; a second pin of the PWM controller U1 is connected with the collector of a triode Q5 through a twenty-ninth resistor R29; the third inductor L3 is grounded through a sixth diode D6, a thirty-third resistor R33, a thirty-second resistor R32 and a thirty-first resistor R31 in sequence; the base electrode of the triode Q5 is connected between the thirty-first resistor R31 and the thirty-second resistor R32 through the thirty-second resistor R30, and the emitter electrode of the triode Q5 is respectively connected with one end of the third capacitor C3 and one end of the fourth capacitor C4 and grounded; the other end of the third capacitor C3 is connected between the sixth diode D6 and the thirty-third resistor R33, and the other end of the fourth capacitor C4 is connected to the collector of the transistor Q5 through the twenty-ninth resistor R29.

A third pin of the PWM controller U1 is connected to the fifth transformer T5 through a fifteenth resistor R15 and a fourteenth resistor R14; a fourth pin of the PWM controller U1 is connected to the fifth transformer T5 through a twelfth diode D12 and a thirty-ninth resistor R39, and a forty-third resistor R43 is connected to two ends of the thirty-ninth resistor R39; a fourth pin of the PWM controller U1 is grounded sequentially through a twelfth resistor R12 and a second schottky diode ZD2, the fourth pin of the PWM controller U1 is connected to a fifth capacitor C5 and a sixth capacitor C6, respectively, and the fifth capacitor C5 and the sixth capacitor C6 are connected in parallel and grounded; a fifth pin of the PWM controller U1 is connected to the gate of the first MOS transistor Q1 through a twenty-third resistor R23; a ninth pin of the PWM controller U1 is connected to the source of the second MOS transistor Q2; a tenth pin of the PWM controller U1 is connected to an eighteenth resistor R18, a nineteenth resistor R19 and a twentieth resistor R20, respectively, and grounded, and the eighteenth resistor R18, the nineteenth resistor R19 and the twentieth resistor R20 are connected in parallel; an eleventh pin of the PWM controller U1 is connected to a thermistor NTC through a seventeenth resistor R17 and grounded, and both ends of the seventeenth resistor R17 and the thermistor NTC are connected to a thirty-fifth capacitor C35; the twelfth pin of the PWM controller U1 is grounded; the thirteenth pin of the PWM controller U1 is connected to the ninth resistor R9 and the thirty-fourth capacitor C34, respectively, the ninth resistor R9 is connected to the fourth pin of the PWM controller U1, and the thirty-fourth capacitor C34 is grounded.

The rectifying and filtering output unit 5 comprises a third transformer T3, a third MOS transistor Q3 and a thirteenth diode D13; the drain of the third MOS transistor Q3 is connected to the second transformer T2 through a thirteenth diode D13, and the source of the third MOS transistor Q3 is connected to the first transformer T3; one end of a third transformer T3 is connected with the second transformer T2, and the other end of the third transformer T3 is connected with an LED lamp; a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a twenty-third capacitor C23, a forty-second resistor R42, a forty-third resistor R43, a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a twenty-third capacitor C23, a forty-second resistor R42 and a forty-third resistor R43 are connected between the third MOS transistor Q3 and the thirteenth diode D13 in parallel and are grounded; the second transformer T2 is connected to the cathode of the thirteenth diode D13 sequentially through a fourth eleventh resistor R41 and a thirty-third capacitor C33, and a forty-fourth resistor R44 is connected to both ends of the forty-first resistor R41; the drain of the third MOS transistor Q3 is connected to the source of the third MOS transistor Q3 through a first resistor R1.

The de-ripple unit 6 includes a twenty-first diode D21, a twenty-second diode D22, a twenty-fifth diode D25, a thirteenth capacitor C13, and a fifty-third resistor R53; the twenty-first diode D21 and the twenty-second diode D22 are connected in series, and the anode of the twenty-second diode D22 is connected with the thirteenth capacitor C13; the twenty-fifth diode D25 is connected in series with the fifty-third resistor R53; the second transformer T2 is grounded through a twelfth capacitor C12, a fifty-fourth resistor R54 and a twenty-third diode D23 in sequence, and the fifty-third resistor R53 is connected between the twelfth capacitor D12 and the fifty-fourth resistor R54; the drain of the third MOS transistor Q3 is connected to a fifty-th resistor R50 and a twenty-first diode D21, respectively, and the fifty-th resistor R50 is connected to ground through a fifty-first resistor R51 and a thirteenth capacitor C13; the gate of the third MOS transistor Q3 is grounded through a fifth twelfth resistor R52 and a thirteenth capacitor C13 in sequence, and the source of the third MOS transistor Q3 is connected with a fifty-second resistor R52 through a twenty-sixth diode D26 and a twenty-fourth diode D24 in sequence; the fifty-third resistor R53 and the fifty-third resistor R50 are connected in series and return to the ground through the third MOS transistor Q3 and the LED light source, so that the voltage of the thirteenth capacitor C13 can be reduced by reducing the fifty-third resistor R50 or increasing the fifty-third resistor R53, the on-resistance of the third MOS transistor Q3 is increased, and the ripple is reduced; the twenty-first diode D21 and the twenty-second diode D22 function: the thirteenth capacitor C13 is rapidly charged by the positive half period during startup, and the third MOS transistor Q3 is rapidly switched on; the fifty-second resistor R52 is a driving resistor of the third MOS transistor Q3; the twenty-fourth diode D24 is clamped with the twenty-sixth diode D26.

In a specific embodiment of the present invention, as shown in fig. 3, one end of the second transformer T2 is grounded through an eighth resistor R8, a tenth resistor R10, a thirteenth resistor R13 and a fourteenth capacitor C14 in sequence, and a resistor is removed; an eleventh pin of the PWM controller U1 is connected with a thermistor NTC through a seventeenth resistor R17 and is grounded, a thirty-fifth capacitor C35 is connected to two ends of the seventeenth resistor R17 and the thermistor NTC, and the connection of the eleventh pin of the PWM controller U1 is removed; a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a twenty-third capacitor C23, a forty-second resistor R42, a forty-third resistor R43, a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a twenty-third capacitor C23, a forty-second resistor R42 and a forty-third resistor R43 are connected between the third MOS transistor Q3 and the thirteenth diode D13 in parallel and are grounded; removing two capacitors and one resistor; the same function is realized; the fifty-third resistor R53 and the fifty-third resistor R50 are connected in series and return to the ground through the third MOS transistor Q3 and the LED light source, so that the voltage of the thirteenth capacitor C13 can be reduced by reducing the fifty-third resistor R50 or increasing the fifty-third resistor R53, the on-resistance of the third MOS transistor Q3 is increased, and the ripple is reduced; the twenty-first diode D21 and the twenty-second diode D22 function: the thirteenth capacitor C13 is rapidly charged by the positive half period during startup, and the third MOS transistor Q3 is rapidly switched on; the fifty-second resistor R52 is a driving resistor of the third MOS transistor Q3; the twenty-fourth diode D24 is clamped with the twenty-sixth diode D26.

In another embodiment of the present invention, as shown in fig. 4, during the Ton when the second MOS transistor Q2 is turned on, the input power Ui powers on the N1 winding of the primary winding of the second transformer T2, the N1 winding has the current i1 flowing through, the self-induced electromotive force is generated at both ends, meanwhile, the induced electromotive force is also generated at both ends of the N2 winding, but no loop current is generated due to the function of the rectifier diode DB1, which is equivalent to an open circuit, and the second transformer T2 is equivalent to an energy storage inductor. At the instant when the control switch K is suddenly turned off from on, the current i1 flowing through the primary winding of the second transformer T2 suddenly becomes 0, and the magnetic flux cannot suddenly change, so during Toff when the second MOS transistor Q2 is turned off, the magnetic flux in the core of the second transformer T2 is mainly maintained by the current in the N2 winding loop, and a flyback current is generated in N2 for supplying power.

The utility model discloses a theory of operation: during the Ton period when the second MOS transistor Q2 is turned on, the input power Ui energizes the N1 winding of the primary winding of the second transformer T2, a current i1 flows through the N1 winding, self-induced electromotive force is generated at both ends, an induced electromotive force is also generated at both ends of the N2 winding, but no loop current is generated due to the action of the rectifier diode DB1, which corresponds to an open circuit, and the second transformer T2 corresponds to an energy storage inductor. At the moment when the control switch K is suddenly turned from on to off, the current i1 flowing through the primary coil of the second transformer T2 is suddenly 0, and the magnetic flux cannot suddenly change, so that during Toff when the second MOS transistor Q2 is turned off, the magnetic flux in the iron core of the second transformer T2 is mainly maintained by the current in the N2 coil loop, and a flyback current is generated in the N2 for supplying power; during the negative half cycle of the second transformer T2, the twelfth capacitor C12 is charged through a twenty-third diode D23 and a fifty-fourth resistor R54: when the second transformer T2 has a positive half cycle, the second transformer T2 is rectified by a fifth-thirteenth resistor R53 and a twenty-fifth diode D25 and is superposed with the voltage charged in the negative half cycle of the twelfth capacitor C12 to charge the thirteenth capacitor C13, so that the voltage is boosted, the voltage of the thirteenth capacitor C13 is higher than that of the LED +, and the third MOS transistor Q3 is turned on for half; when the ripple is added to the direct current, the voltage of the LED + rises, and the gate voltage of the third MOS transistor Q3 is fixed, so that the voltage of the source of the third MOS transistor Q3 becomes smaller, the internal resistance of the third MOS transistor Q3 increases, and the top-clipping and ripple-removing are realized.

Above, only be the concrete implementation of the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art is in the technical scope of the present invention, according to the technical solution of the present invention and the design of the present invention, equivalent replacement or change should be covered within the protection scope of the present invention.

Claims (8)

1. An LED silicon controlled rectifier dimming power supply circuit is characterized by comprising an EMC circuit unit, a rectifying and filtering unit, a flyback and voltage transformation unit, a PWM controller unit, a rectifying and filtering output unit and a ripple removing unit; the EMC circuit unit is connected with the rectifying and filtering unit, and the rectifying and filtering unit is respectively connected with the flyback transformer unit and the PWM controller unit; the flyback transformer unit is respectively connected with the PWM controller unit and the rectification filter output unit; the rectification filtering unit is connected with the ripple removing unit.

2. The LED silicon controlled rectifier dimming power supply circuit of claim 1, wherein the EMC circuit unit comprises a first transformer, a fourth transformer, a first inductance and a second inductance; one end of the first transformer is connected with an external power supply, and the other end of the first transformer is connected with the fourth transformer through the first inductor and the second inductor respectively; and the two ends of the first inductor are connected with a fifth resistor, and the two ends of the second inductor are connected with a sixth resistor.

3. The LED silicon controlled rectifier dimming power supply circuit according to claim 2, wherein the rectifying and filtering unit comprises a rectifying diode, a first MOS (metal oxide semiconductor) tube and a third inductor; the rectifier diode is connected with the fourth transformer, and the anode of the rectifier diode is connected with the third inductor; the source electrode of the first MOS tube is connected with the cathode of the rectifier diode and grounded, the grid electrode of the first MOS tube is connected with the cathode of the rectifier diode and grounded sequentially through a thirteenth resistor and a seventeenth capacitor, and the drain electrode of the first MOS tube is connected with one end of the third inductor through an eighteenth capacitor; the other end of the third inductor is connected with the cathode of the rectifier diode through a twenty-fifth resistor and the first capacitor in sequence and is grounded.

4. The LED silicon controlled rectifier dimming power supply circuit according to claim 3, wherein the flyback transformer unit comprises a second MOS tube, a second transformer, a fifth transformer and a third Schottky diode; one end of the second transformer is connected with the third inductor, and the other end of the second transformer is connected with the fifth transformer through a seventh capacitor; the drain electrode of the second MOS tube is respectively connected with the second transformer and the positive electrode of the seventh diode, and the grid electrode of the second MOS tube is connected with the third Schottky diode through an eleventh resistor and grounded; the source electrode of the second MOS tube is connected with the negative electrode of a ninth diode, and the positive electrode of the ninth diode is connected between the eleventh resistor and the third Schottky diode; one end of the second transformer is grounded through an eighth resistor, a tenth resistor, a thirteenth resistor and a fourteenth capacitor in sequence, and one end of the fourteenth capacitor is connected between the eleventh resistor and the cathode of the third Schottky diode.

5. The LED silicon controlled rectifier dimming power supply circuit according to claim 4, wherein the PWM controller unit comprises a triode and a PWM controller; the second pin of the PWM controller is connected with the collector of the triode through a twenty-ninth resistor; the third inductor is grounded through a sixth diode, a thirty-third resistor, a thirty-second resistor and a thirty-first resistor in sequence; the base electrode of the triode is connected between the thirty-first resistor and the thirty-second resistor through a thirty-second resistor, and the emitter electrode of the triode is respectively connected with one end of a third capacitor and one end of a fourth capacitor and grounded; the other end of the third capacitor is connected between the sixth diode and the thirty-third resistor, and the other end of the fourth capacitor is connected with the collector of the triode through a twenty-ninth resistor.

6. The LED silicon controlled rectifier dimming power supply circuit according to claim 5, wherein a third pin of the PWM controller is connected with the fifth transformer through a fifteenth resistor and a fourteenth resistor; a fourth pin of the PWM controller is connected with the fifth transformer through a twelfth diode and a thirty-ninth resistor, and the fourth pin of the PWM controller is grounded through the twelfth resistor and the second Schottky diode in sequence; a fifth pin of the PWM controller is connected with the first MOS tube through a twenty-third resistor; a ninth pin of the PWM controller is connected with a source electrode of the second MOS tube; the eleventh pin of the PWM controller is connected with a thermistor through a seventeenth resistor and is grounded; and a thirteenth pin of the PWM controller is respectively connected with a ninth resistor and a thirty-fourth capacitor.

7. The LED silicon controlled rectifier dimming power supply circuit according to claim 4, wherein the rectification filter output unit comprises a third transformer, a third MOS (metal oxide semiconductor) tube and a thirteenth diode; the drain electrode of the third MOS tube is connected with the second transformer through the thirteenth diode, and the source electrode of the third MOS tube is connected with one end of the third transformer; one end of the third transformer is connected with the second transformer, and the other end of the third transformer is connected with the LED lamp.

8. The LED silicon controlled rectifier dimming power supply circuit according to claim 7, wherein the ripple removing unit comprises a twenty-first diode, a twenty-second diode, a twenty-fifth diode, a thirteenth capacitor and a fifty-third resistor; the twenty-first diode and the twenty-second diode are connected in series, and the anode of the twenty-second diode is connected with the thirteenth capacitor; the twenty-fifth diode and the fifty-third resistor are connected in series; the second transformer is grounded through a twelfth capacitor, a fifty-fourth resistor and a twenty-third diode in sequence, and the fifty-third resistor is connected between the twelfth capacitor and the fifty-fourth resistor; the drain electrode of the third MOS tube is respectively connected with a fifty-th resistor and the twenty-first diode, and the fifty-th resistor is connected with the thirteenth capacitor through a fifty-first resistor and grounded; the grid electrode of the third MOS tube is grounded through a fifth-twelfth resistor and the thirteenth capacitor in sequence, and the source electrode of the third MOS tube is connected with the fifty-second resistor through a twenty-sixth diode and a twenty-fourth diode in sequence.

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