CN108024420B - LED low-voltage driving circuit and LED lamp - Google Patents

LED low-voltage driving circuit and LED lamp Download PDF

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Publication number
CN108024420B
CN108024420B CN201810014841.6A CN201810014841A CN108024420B CN 108024420 B CN108024420 B CN 108024420B CN 201810014841 A CN201810014841 A CN 201810014841A CN 108024420 B CN108024420 B CN 108024420B
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capacitor
output
resistor
led
module
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CN108024420A (en
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朱高贵
洪海川
王智
祝永勤
林敢
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Meizhi Photoelectric Technology Co ltd
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Midea Intelligent Lighting and Controls Technology Co Ltd
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    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30Driver circuits
    • H05B45/37Converter circuits
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

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  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

The invention provides an LED low-voltage driving circuit and an LED lamp, wherein the LED low-voltage driving circuit comprises: the rectifying module comprises a rectifying bridge pile, wherein the rectifying bridge pile is connected to the low-voltage power supply and comprises a first output end and a second output end so as to output direct current; an EMI suppression module connected to the first output, the EMI (Electro Magnetic Interference ) suppression module for suppressing electromagnetic interference; and the constant current control module is respectively connected to the first output end and the EMI suppression module and is used for providing constant current voltage for the LED load. According to the technical scheme, matching with different front-stage electronic transformers is achieved, power supply to the LED load is achieved, phenomena of flickering, sound and the like caused by the front-stage electronic transformers in operation can be reduced, and therefore stability of products is improved.

Description

LED low-voltage driving circuit and LED lamp
Technical Field
The invention relates to the field of electronic illumination, in particular to an LED low-voltage driving circuit and an LED lamp.
Background
The LED light source is used as a common light source, and is increasingly applied in the life of users, and the LED light source comprises an MR16LED spotlight, a smart dimming LED, a vehicle-mounted LED lamp and a solar LED, and is gradually replacing the traditional incandescent lamp as a lighting tool due to the characteristics of high luminous efficiency, long service life, vivid color, environmental protection and the like, wherein the MR16LED low-voltage spotlight can replace the traditional low-voltage halogen lamp and quartz lamp, but has the following defects in use:
the replaced MR16LED spotlight cannot be matched with the electronic transformer in the original driving circuit, so that the LED spotlight cannot be lighted, the lighted LED spotlight has a flicker problem or a sound problem, and the like, so that the LED spotlight cannot be compatible with the sub-transformer in the original halogen lamp driving circuit or the quartz lamp driving circuit.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art or related art.
To this end, an object of the present invention is to propose a low voltage driving circuit for LEDs.
Therefore, another object of the present invention is to provide an LED lamp.
To achieve the above object, an embodiment of the present invention provides an LED low voltage driving circuit, including: a low voltage power supply; the rectifying module comprises a rectifying bridge pile, wherein the rectifying bridge pile is connected to the low-voltage power supply and comprises a first output end and a second output end so as to output direct current; an EMI suppression module connected to the first output, the EMI (Electro Magnetic Interference ) suppression module for suppressing electromagnetic interference; and the constant current control module is respectively connected to the first output end and the EMI suppression module and is used for providing constant current voltage for the LED load.
In the technical scheme, after the commercial power passes through the electronic transformer, the direct-current low voltage or alternating-current low voltage which is more than or equal to 3V and less than or equal to 60V is formed, the direct-current low voltage or alternating-current low voltage is rectified into direct current after passing through the rectification module, the rectification module comprises a finishing bridge pile, the direct current output by the rectification bridge pile passes through the EMI suppression module to suppress electromagnetic interference, and the direct-current electric energy after the electromagnetic interference is suppressed can be input into the constant-current control module so as to perform energy conversion according to different direct-current input voltages through the constant-current control module, so that the matching with different front-stage electronic transformers is realized, the power supply to the LED load is realized, and the phenomena of flickering, sound of the voice and the like caused by the working of the front-stage electronic transformer can be reduced, thereby improving the stability of products.
It should be understood that the LED low-voltage driving circuit provided by the present invention may have various operation modes, including a step-up mode, a step-down mode, and a step-up-step-down mode, so as to achieve compatibility with different front-stage electronic transformers.
The finishing bridge stack comprises 4 rectifier diodes, the rectifier diodes have higher switching frequency, and schottky diodes with fast recovery time and low conduction voltage drop can be used for improving efficiency, wherein the average current level of the schottky diodes needs to be larger than average output current, and reverse breakdown voltage needs to be larger than output voltage.
In addition, the LED low-voltage driving circuit in the above embodiment provided by the present invention may further have the following additional technical features:
in the above technical solution, preferably, the method further includes: a filtering module comprising: the energy storage filter inductance, the one end of energy storage filter inductance is connected to first output.
In the technical scheme, through the arrangement of the energy storage filter inductor, on one hand, the current flowing through the energy storage filter inductor can be converted into magnetic energy for energy storage, and on the other hand, the current flowing into the EMI suppression module can be limited.
The energy storage filter inductor can be a chip inductor or a work inductance made of nickel-zinc materials.
In any one of the above embodiments, preferably, the EMI suppression module includes: the surface-mounted magnetic beads are used for eliminating EMI noise, and one end of each surface-mounted magnetic bead is connected to the other end of the filter capacitor; the anode of the follow current diode is connected to the other end of the patch type magnetic bead; wherein, one end of the patch type magnetic bead is determined as a suppression input end of the EMI suppression module, and the cathode of the freewheel diode is determined as a suppression output end of the EMI suppression module.
In this technical scheme, through setting up the SMD magnetic bead, can effectively eliminate the EMI noise that does not need to promote drive circuit's stability.
In any of the foregoing aspects, preferably, the EMI suppression module includes: and the anode of the freewheel diode is connected to the RC filter assembly at the other end of the filter capacitor and is arranged in parallel with the freewheel diode, the RC filter assembly comprises a first resistor and a first capacitor which are connected in series, and the RC filter assembly is used for suppressing electromagnetic interference, wherein the anode of the freewheel diode is determined to be the suppression input end of the EMI suppression module, and the cathode of the freewheel diode is determined to be the suppression output end of the EMI suppression module.
In the technical scheme, the RC filter assembly is arranged, so that electromagnetic interference and conducted interference can be restrained by the RC filter assembly.
In any of the foregoing aspects, preferably, the EMI suppression module includes: one end of the patch type magnetic bead is connected to the first output end, and the patch type magnetic bead is used for eliminating EMI noise; the anode of the follow current diode is connected to the other end of the patch type magnetic bead; the RC filter component is arranged in parallel with the free-wheeling diode and comprises a first resistor and a first capacitor which are connected in series, one end of the first resistor is connected to the anode of the free-wheeling diode, the other end of the first resistor is connected to one end of the first capacitor, the other end of the first capacitor is connected to the cathode of the free-wheeling diode, and the RC filter component is used for inhibiting electromagnetic interference, wherein one end of the patch type magnetic bead is determined to be an inhibition input end of the EMI inhibition module, and the cathode of the free-wheeling diode is determined to be an inhibition output end of the EMI inhibition module.
In the technical scheme, the patch type magnetic beads and the RC filter assembly are sequentially arranged, so that the secondary filtering of electromagnetic interference is realized, electromagnetic interference and conduction interference can be simultaneously restrained, the interference restraining effect is better, and the circuit can pass European Union CE authentication.
The freewheeling diode can also be a schottky diode, and can provide a path for the energy released by the energy storage filter inductor during ton.
In any one of the above solutions, preferably, the constant current control module includes: the constant-current control chip comprises an overvoltage protection end, a loop compensation end, a dimming input end, a grounding end, a switch end, an internal power supply output end, a chip power supply end and a current sampling end, wherein the overvoltage protection end is connected to one end of a second resistor; one end of the third resistor is connected to the power supply end of the chip, and the other end of the third resistor is connected to the current sampling end; and the fourth resistor is arranged in parallel with the third resistor.
In the technical scheme, the constant current control chip is arranged to supply power to the chip through the chip power supply section, the MOSFET is arranged in the constant current control chip, the drain electrode of the MOSFET corresponds to the switch end, the source electrode of the MOSFET corresponds to the grounding end, and the voltage of the current sampling end is controlled to be a constant value so as to realize stable current output through the third resistor and the fourth resistor, so that stable power supply to the LED load is realized.
The constant current control chip can be BP1808 or BP1808A.
In any of the above embodiments, preferably, the method further includes: one end of the fourth capacitor is connected to the suppression output end, the other end of the fourth capacitor is grounded, and the fourth capacitor is used for boosting the constant-current voltage; the first end of the fifth resistor is connected to the suppression output end, the other end of the fifth resistor is connected to the overvoltage protection end, the other end of the second resistor is grounded, the other end of the second capacitor is grounded, the dimming input end is empty, the grounding end is grounded, the switch end is connected in series with the fifth capacitor and then grounded, the other end of the third capacitor is grounded, and the second output end is used as an output negative electrode of the LED load.
In the technical scheme, the structure of the BOOST circuit of the topological structure is realized by connecting the fourth capacitor and the fifth resistor into the circuit and matching the fourth capacitor and the fifth resistor with the energy storage filter inductor, so that the BOOST working mode of the LED low-voltage driving circuit is realized.
Specifically, the energy storage filter inductor can mutually convert electric energy and magnetic field energy, when the control switch end is in an off state, the inductor converts the electric energy into the magnetic field energy to be stored, when the control switch end is in an off state, the energy storage filter inductor can convert the stored magnetic field energy into electric field energy, the energy and direct current output by the rectifying module are superposed and then are filtered by the flywheel diode and the first capacitor to obtain smooth direct current voltage, the smooth direct current voltage is provided for a load, and the voltage is formed after the input power voltage and the magnetic field energy of the inductor are converted into the superposition of the electric energy, so that the output voltage is higher than the input voltage, namely the boosting process is completed.
In any of the above embodiments, preferably, the method further includes: the fourth capacitor is connected with the energy storage filter inductor in series, one end of the fourth capacitor is connected to the first output end, the other end of the fourth capacitor is connected to one end of the energy storage filter inductor, the other end of the energy storage filter inductor is connected to the switch end, the other end of the fourth capacitor is determined to be an output negative electrode of the LED load, the fourth capacitor is used for reducing constant current voltage, the other end of the second resistor is grounded, the other end of the second capacitor is grounded, the dimming input end is grounded after being connected with the fifth capacitor in series, the grounding end is empty, and the other end of the third capacitor is grounded.
In the technical scheme, the structure of the BUCK voltage reduction circuit with the topological structure is realized by connecting the fourth capacitor into the circuit and matching with the energy storage filter inductor, so that the voltage reduction working mode of the LED low-voltage driving circuit is realized.
In any of the above embodiments, preferably, the method further includes: the fourth capacitor is connected with the energy storage filter inductor in parallel and is used for boosting or reducing the constant-current voltage; and the first end of the fifth resistor is connected to the suppression output end, the other end of the fifth resistor is connected to the overvoltage protection end, the other end of the second resistor, the other end of the second capacitor and the other end of the third capacitor are respectively connected to the second output end, the dimming input end is connected with the fifth capacitor in series and then is connected to the second output end, and the first output end is determined to be an output negative electrode of the LED load.
In the technical scheme, the structure of the BOOST-BUCK BOOST circuit of the topological structure is realized by adjusting the connection mode of the fourth capacitor and the fifth resistor, and the BOOST-BUCK working mode of the LED low-voltage driving circuit is further realized.
The voltage boosting and boosting circuit adopts a BOOST-BUCK circuit, and the polarity of the output voltage is opposite to that of the input voltage.
In any of the foregoing solutions, preferably, the filtering module further includes: and one end of the ninth capacitor is connected to the first output end, and the other end of the ninth capacitor is connected to the second output end.
In the technical scheme, the filtering function is realized by arranging the sixth capacitor.
In any of the foregoing solutions, preferably, the filtering module further includes: and the anode of the electrolytic capacitor is connected to the first output end, and the cathode of the electrolytic capacitor is connected to the second output end.
In the technical scheme, the voltage stabilizing and filtering functions are realized through energy storage and filtering of the electrolytic capacitor.
Wherein the withstand voltage of the electrolytic capacitor is 25V, and the capacity is more than 470uF.
In any of the above solutions, preferably, the LED load is an MR16LED spotlight.
An embodiment of a second aspect of the invention provides an LED luminaire comprising an LED low voltage driving circuit according to any of the embodiments of the first aspect of the invention.
According to the technical scheme, the constant current control module is used for carrying out energy conversion according to different direct current input voltages, so that the LED load is matched with different front-stage electronic transformers, the LED load is powered, the phenomena of flickering, rattling and the like caused by the working of the front-stage electronic transformers can be reduced, and the product stability is improved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, or may be learned by practice of the invention.
Drawings
Fig. 1 shows a schematic diagram of a structure of an LED low voltage driving circuit according to an embodiment of the present invention;
fig. 2 shows a schematic diagram of a structure of an LED low voltage driving circuit according to another embodiment of the present invention;
fig. 3 shows a schematic diagram of a structure of an LED low-voltage driving circuit according to still another embodiment of the present invention;
fig. 4 shows a schematic diagram of a structure of an LED low-voltage driving circuit according to still another embodiment of the present invention;
fig. 5 shows a schematic diagram of a structure of an LED low-voltage driving circuit according to still another embodiment of the present invention;
fig. 6 shows a schematic structural diagram of a constant current control chip according to an embodiment of the present invention;
FIG. 7 shows a graph of chip soft start time versus COMP capacitance, according to one embodiment of the invention.
Detailed Description
In order that the above-recited objects, features and advantages of the present invention will be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those described herein, and the scope of the invention is therefore not limited to the specific embodiments disclosed below.
As shown in fig. 1 to 3, an LED low voltage driving circuit according to an embodiment of the present invention includes: a low voltage power supply; the rectifying module 10 comprises a rectifying bridge pile, wherein the rectifying bridge pile is connected to the low-voltage power supply and comprises a first output end and a second output end so as to output direct current; an EMI suppression module 20 connected to the first output, the EMI (Electro Magnetic Interference ) suppression module for suppressing electromagnetic interference; the constant current control module 30 is connected to the first output end and the EMI suppression module 20, respectively, and the constant current control module 30 is used for providing a constant current voltage to the LED load.
In this embodiment, after the commercial power passes through the electronic transformer, a dc low voltage or an ac low voltage greater than or equal to 3V and less than or equal to 60V is formed, the dc low voltage or the ac low voltage is rectified into a dc power after passing through the rectifying module 10, the rectifying module 10 includes a rectifying bridge stack, the dc power output by the rectifying bridge stack passes through the EMI suppression module 20 to suppress electromagnetic interference, and the dc power after electromagnetic interference is suppressed can be input into the constant current control module 30 to perform energy conversion according to different dc input voltages through the constant current control module 30, so as to realize matching with different front-stage electronic transformers, so as to realize power supply to the LED load, reduce phenomena such as flicker, ringing, and the like caused when the front-stage electronic transformer works, and thus improve product stability.
It should be understood that the LED low-voltage driving circuit provided by the present invention may have various operation modes, including a step-up mode, a step-down mode, and a step-up-step-down mode, so as to achieve compatibility with different front-stage electronic transformers.
As shown in fig. 1 to 5, the finishing bridge includes 4 rectifier diodes (102, 104, 106 and 108 respectively), and a fuse 110 is further connected to the input end of the rectifier bridge, and the rectifier diodes may use schottky diodes with fast recovery time and low on-voltage drop for improving efficiency because of higher switching frequency, wherein the average current level of the schottky diodes needs to be greater than the average output current, and the reverse breakdown voltage needs to be greater than the output voltage.
In addition, the LED low-voltage driving circuit in the above embodiment provided by the present invention may further have the following additional technical features:
as shown in fig. 1 to 5, in the above embodiment, it is preferable that: a filtering module 40 comprising: the energy storage filter inductor 402, one end of the energy storage filter inductor 402 is connected to the first output end.
In this technical solution, by providing the energy storage filter inductor 402, on one hand, the current flowing through the energy storage filter inductor 402 can be converted into magnetic energy for energy storage, and on the other hand, the current flowing into the EMI suppression module 20 can be limited.
The energy storage filter inductor 402 may be a chip inductor or a work inductance made of nickel-zinc material.
Embodiment one:
as shown in fig. 2, in any of the above embodiments, preferably, the EMI suppression module 20 includes: the patch type magnetic beads 202, one end of the patch type magnetic beads 202 is connected to the other end of the filter capacitor, and the patch type magnetic beads 202 are used for eliminating EMI noise; a freewheel diode 204, wherein an anode of the freewheel diode 204 is connected to the other end of the patch-type magnetic bead 202; wherein one end of the patch-type magnetic bead 202 is determined as a suppression input of the EMI suppression module 20, and a cathode of the flywheel diode 204 is determined as a suppression output of the EMI suppression module 20.
In this embodiment, by providing the patch type magnetic beads 202, unnecessary EMI noise can be effectively eliminated to improve the stability of the driving circuit.
Embodiment two:
as shown in fig. 3, in any of the above embodiments, the EMI suppression module 20 preferably includes: and the anode of the freewheeling diode 204 is connected to the RC filter component at the other end of the filter capacitor, and is arranged in parallel with the freewheeling diode 204, the RC filter component comprises a first resistor 206 and a first capacitor 208 which are connected in series, and the RC filter component is used for suppressing electromagnetic interference, wherein the anode of the freewheeling diode 204 is determined as a suppression input end of the EMI suppression module 20, and the cathode of the freewheeling diode 204 is determined as a suppression output end of the EMI suppression module 20.
In this embodiment, by providing an RC filter assembly, the RC filter assembly can achieve suppression of electromagnetic interference as well as conducted interference.
Embodiment III:
as shown in fig. 1, 4 and 5, in any of the above embodiments, the EMI suppression module 20 preferably includes: the patch type magnetic bead 202, one end of the patch type magnetic bead 202 is connected to the first output end, and the patch type magnetic bead 202 is used for eliminating EMI noise; a freewheel diode 204, wherein an anode of the freewheel diode 204 is connected to the other end of the patch-type magnetic bead 202; the RC filter component is arranged in parallel with the freewheeling diode 204 and comprises a first resistor 206 and a first capacitor 208 which are connected in series, one end of the first resistor 206 is connected to the anode of the freewheeling diode 204, the other end of the first resistor 206 is connected to one end of the first capacitor 208, the other end of the first capacitor 208 is connected to the cathode of the freewheeling diode 204, and the RC filter component is used for suppressing electromagnetic interference, wherein one end of the patch-type magnetic bead 202 is determined to be a suppression input end of the EMI suppression module 20, and the cathode of the freewheeling diode 204 is determined to be a suppression output end of the EMI suppression module 20.
In this embodiment, by sequentially setting the patch type magnetic beads 202 and the RC filter component, the secondary filtering of electromagnetic interference is realized, electromagnetic interference and conductive interference can be simultaneously suppressed, the suppression effect on interference is better, and the line can pass the CE authentication of the european union.
The freewheeling diode 204 may be a schottky diode, and may be used to provide a path for the energy released by the tank filter inductor 402 during ton.
As shown in fig. 1 to 5, in any one of the above embodiments, preferably, the constant current control module 30 includes: the constant current control chip 302 comprises an overvoltage protection end, a loop compensation end, a dimming input end, a grounding end, a switch end, an internal power supply output end, a chip 302 power supply end and a current sampling end, wherein the overvoltage protection end is connected to one end of the second resistor 304, the loop compensation end is connected to one end of the second capacitor 306, the switch end is connected to the inhibition input end, the internal power supply output end is connected to one end of the third capacitor 308 in series, the chip 302 power supply end is connected to the inhibition output end, and the current sampling end is determined to be an output anode of the LED load; the third resistor 310, one end of the third resistor 310 is connected to the power supply end of the chip 302, and the other end of the third resistor 310 is connected to the current sampling end; the fourth resistor 312 is disposed in parallel with the third resistor 310.
In this embodiment, by providing the constant current control chip 302, power is supplied to the chip 302 through a power supply section of the chip 302, a MOSFET tube is provided in the constant current control chip 302, a drain electrode of the MOSFET tube corresponds to a switch end, a source electrode of the MOSFET tube corresponds to a ground end, and by controlling a voltage of the current sampling end to be a constant value, stable current output is achieved through the third resistor 310 and the fourth resistor 312, so that stable power supply to the LED load is achieved.
The constant current control chip 302 may be BP1808 or BP1808A, and the pins in fig. 1 to 6 are numbered as shown in table 1.
TABLE 1
Pin number Pin name Description of the invention
1 OVP An overvoltage protection terminal connected to a voltage dividing resistor between the output pin and ground
2 COMP A loop compensation end connected with a compensation resistor (optional) and a series compensation capacitor to ground
3 DIM Light-adjusting input end suspended when not adjusting light
4 GND Chip grounding end
5 SW A switch terminal connected with the drain of the internal MOSFET and the anode of the external rectifying diode
6 VDD Internal power supply output end of chip
7 VOUT Output voltage connection point and provide power supply for chip
8 CS LED current sampling end, connecting sampling resistor to VOUT end
Fig. 6 shows a schematic internal structure of the constant current control chip 302.
As shown in fig. 1 to 5, sampling resistors 310 and 312 connected to a CS (current sampling end) are used, the voltage of the pin 8 (current sampling end) of the constant current control chip 302 is maintained at 0.2V, and the constant current control chip 302 is controlled to continuously output a constant current value so as to supply power to the LED lamp beads.
As shown in fig. 6, the constant current control chip 302 operates in a fixed frequency 400KHz mode, by sampling the voltage (V-) across the sampling resistor between the CS pin (current sampling terminal) and the VOUT pin (chip power supply terminal), comparing it with the internal reference 0.2V (v+), controlling the voltage (v+) of COMP (loop compensation terminal) by means of an Error Amplifier (EA), comparing the voltage of COMP with the fixed sawtooth wave (V-) generated by the internal oscillation to determine the on-time, when the output current decreases, the voltage across the sampling resistor is less than 0.2V, pulling the COMP voltage up by EA, increasing the pass time, thus maintaining the voltage across the sampling resistor at 0.2V, and the output current maintains the set value, and vice versa.
As shown in fig. 6 and 7, BP1808 has a soft start function built in, and when COMP voltage rises to 1V, soft start ends and the built-in MOSFET starts to switch. When the COMP capacitance value is smaller than 8nF, the COMP voltage rises with the maximum slope of 1V/ms, the soft start time is 1ms, if longer soft start time is needed, the capacitance of the COMP terminal can be properly increased, when the COMP capacitance value is larger than 8nF, the COMP capacitance is charged by the soft start charging current with the maximum value of 8uA until the COMP voltage rises to 1V, and the soft start time at the moment is tss:
when the voltage at DIM terminal (dimming input terminal) is continuously less than 0.2V for more than 15ms, the constant current control chip 302 enters a shutdown state in which the quiescent current is reduced to 80ua and comp capacitance is discharged to zero.
As shown in fig. 6, the overvoltage protection end (1 st pin) is provided with an OVP comparator, so that the constant current control chip 302 is adopted, overvoltage protection can be realized in a boost operation mode or a buck-boost operation mode, the overvoltage protection is triggered by an LED open circuit, the overvoltage protection point can be set through an external voltage dividing resistor, the reference voltage of the OVP comparator is 1.2V, and the hysteresis is 100mV, so that the overvoltage protection voltage is set to be higher than the normal VOUT voltage by more than 30%.
In addition, the constant current control chip 302 also has an overheat adjustment function, and gradually reduces the output current when the driving power source is overheated, thereby controlling the output power and the temperature rise, and keeping the power source temperature at a set value to improve the reliability of the system, and the overheat adjustment temperature point is set to 140 ℃.
Embodiment four:
as shown in fig. 1 to 3, in any of the foregoing embodiments, it preferably further includes: one end of the fourth capacitor 314 is connected to the suppression output end, the other end of the fourth capacitor 314 is grounded, and the fourth capacitor 314 is used for boosting the constant current voltage; the first end of the fifth resistor 316 is connected to the suppression output end, the other end of the fifth resistor 316 is connected to the overvoltage protection end, the second output end is grounded, the other end of the second resistor 304 is grounded, the other end of the second capacitor 306 is grounded, the dimming input end is empty, the grounding ground is grounded, the switch end is further connected in series with the fifth capacitor 318 and then grounded, the other end of the third capacitor 308 is grounded, and the second output end is used as an output negative electrode of the LED load.
In the technical scheme, the fourth capacitor 314 and the fifth resistor 316 are connected into the circuit and matched with the energy storage filter inductor 402, so that the structure of the BOOST circuit with the topological structure is realized, and the BOOST working mode of the LED low-voltage driving circuit is further realized.
Specifically, the energy storage filter inductor 402 can mutually convert electric energy and magnetic field energy, when the control switch end is in an off state, the inductor converts the electric energy into the magnetic field energy to be stored, when the control switch end is in an off state, the energy storage filter inductor 402 can convert the stored magnetic field energy into electric field energy, the energy and the direct current output by the rectifying module 10 are superposed and then are filtered by the flywheel diode 204 and the first capacitor 208 to obtain a smooth direct current voltage, the smooth direct current voltage is provided for a load, and because the voltage is formed after the input power voltage and the magnetic field energy of the inductor are converted into the superposition of the electric energy, the output voltage is higher than the input voltage, namely, the boosting process is completed.
Specifically, as shown in fig. 1 to 3, taking a topology BOOST circuit as an example,
wherein D is the charge duty cycle, i.e. the on-time of the MosFET, and 0 < D < 1, vo is the output voltage, and Vi is the input voltage.
Fifth embodiment:
as shown in fig. 4, in any of the foregoing embodiments, it is preferable that the method further includes: the fourth capacitor 314 is connected in series with the energy storage filter inductor 402, one end of the fourth capacitor 314 is connected to the first output end, the other end of the fourth capacitor 314 is connected to one end of the energy storage filter inductor 402, the other end of the energy storage filter inductor 402 is connected to the switch end, the other end of the fourth capacitor 314 is determined to be an output negative electrode of the LED load, the fourth capacitor 314 is used for reducing constant current voltage, the other end of the second resistor 304 is grounded, the other end of the second capacitor 306 is grounded, the dimming input end is connected in series with the fifth capacitor 318 and then grounded, the grounded end is empty, and the other end of the third capacitor 308 is grounded.
In this embodiment, the fourth capacitor 314 is connected to the circuit and is matched with the energy storage filter inductor 402 and the MOSFET tube, so that the structure of the BUCK circuit with the topological structure is realized, and the BUCK working mode of the low-voltage driving circuit of the LED is further realized.
Wherein, by controlling the MOSFET to open and close, the energy storage filter inductor 402 generates back electromotive force to realize voltage reduction.
Example six:
as shown in fig. 5, in any of the foregoing embodiments, it is preferable that the method further includes: a fourth capacitor 314, which is parallel connected to the energy storage filter inductor 402, and the fourth capacitor 314 is used for boosting or reducing the constant current voltage; the first end of the fifth resistor 316 is connected to the suppression output end, the other end of the fifth resistor 316 is connected to the overvoltage protection end, wherein the other end of the second resistor 304, the other end of the second capacitor 306 and the other end of the third capacitor 308 are respectively connected to the second output end, the dimming input end is connected to the second output end after being connected in series with the fifth capacitor 318, and the first output end is determined as the output negative electrode of the LED load.
In this embodiment, by adjusting the connection mode of the fourth capacitor 314 and the fifth resistor 316 and matching with the MOSFET, the structure of the BOOST-BUCK circuit with the topology structure is realized, and the BOOST-BUCK working mode of the LED low-voltage driving circuit is further realized.
The voltage boosting and boosting circuit adopts a BOOST-BUCK circuit, and the polarity of the output voltage is opposite to that of the input voltage.
In any of the above embodiments, preferably, the filtering module 40 further includes: and a sixth capacitor 404, one end of the ninth capacitor is connected to the first output terminal, and the other end of the ninth capacitor is connected to the second output terminal.
In this embodiment, the filter function is realized by providing the sixth capacitor 404.
In any of the above embodiments, preferably, the filtering module 40 further includes: and an electrolytic capacitor 406, wherein the positive electrode of the electrolytic capacitor 406 is connected to the first output terminal, and the negative electrode of the electrolytic capacitor 406 is connected to the second output terminal.
In this embodiment, the voltage stabilizing and filtering function is realized by the energy storage and filtering of the electrolytic capacitor 406.
The withstand voltage of the electrolytic capacitor 406 is 25V, and the capacity is more than 470uF.
In any of the above embodiments, preferably, the LED load is an MR16LED spotlight.
The LED lamp provided by the embodiment of the invention comprises the LED low-voltage driving circuit in any of the embodiments.
In the present invention, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more, unless expressly defined otherwise. The terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; "coupled" may be directly coupled or indirectly coupled through intermediaries. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or units referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention.
In the description of the present specification, the terms "one embodiment," "some embodiments," "particular embodiments," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (11)

1. An LED low voltage driving circuit, comprising:
a low voltage power supply;
the rectifying module comprises a rectifying bridge pile, wherein the rectifying bridge pile is connected to the low-voltage power supply and comprises a first output end and a second output end so as to output direct current;
an EMI suppression module connected to the first output terminal, the EMI suppression module configured to suppress electromagnetic interference;
the constant current control module is respectively connected to the first output end and the EMI suppression module and is used for providing constant current voltage for the LED load;
the filtering module comprises an energy storage filtering inductor, and one end of the energy storage filtering inductor is connected to the first output end;
the constant current control module includes:
the constant-current control chip comprises an overvoltage protection end, a loop compensation end, a dimming input end, a grounding end, a switch end, an internal power supply output end, a chip power supply end and a current sampling end, wherein the overvoltage protection end is connected to one end of a second resistor, the loop compensation end is connected to one end of a second capacitor, the switch end is connected to an inhibition input end of the EMI inhibition module, the internal power supply output end is connected to one end of a third capacitor in series, the chip power supply end is connected to an inhibition output end of the EMI inhibition module, and the current sampling end is determined to be an output positive electrode of the LED load;
one end of the third resistor is connected to the power supply end of the chip, and the other end of the third resistor is connected to the current sampling end;
and the fourth resistor is arranged in parallel with the third resistor.
2. The LED low voltage driver circuit of claim 1, wherein the EMI suppression module comprises:
one end of the patch type magnetic bead is connected to the other end of the energy storage filter inductor, and the patch type magnetic bead is used for eliminating EMI noise;
a freewheeling diode, the anode of which is connected to the other end of the patch type magnetic bead;
wherein one end of the patch type magnetic bead is determined as the suppression input end of the EMI suppression module, and a cathode of the freewheel diode is determined as the suppression output end of the EMI suppression module.
3. The LED low voltage driver circuit of claim 1, wherein the EMI suppression module comprises:
the anode of the freewheel diode is connected to the other end of the energy storage filter inductor;
an RC filter assembly connected in parallel with the freewheeling diode, the RC filter assembly including a first resistor and a first capacitor connected in series, the RC filter assembly being configured to suppress electromagnetic interference,
wherein an anode of the freewheel diode is determined as the suppression input of the EMI suppression module and a cathode of the freewheel diode is determined as the suppression output of the EMI suppression module.
4. The LED low voltage driver circuit of claim 1, wherein the EMI suppression module comprises:
a patch type magnetic bead, one end of which is connected to the first output end, wherein the patch type magnetic bead is used for eliminating EMI noise;
a freewheeling diode, the anode of which is connected to the other end of the patch type magnetic bead;
an RC filter component which is arranged in parallel with the freewheeling diode and comprises a first resistor and a first capacitor which are connected in series, wherein one end of the first resistor is connected to the anode of the freewheeling diode, the other end of the first resistor is connected to one end of the first capacitor, the other end of the first capacitor is connected to the cathode of the freewheeling diode, the RC filter component is used for inhibiting electromagnetic interference,
wherein one end of the patch type magnetic bead is determined as the suppression input end of the EMI suppression module, and a cathode of the freewheel diode is determined as the suppression output end of the EMI suppression module.
5. The LED low voltage driving circuit according to claim 1, further comprising:
one end of the fourth capacitor is connected to the suppression output end, the other end of the fourth capacitor is grounded, and the fourth capacitor is used for boosting the constant-current voltage;
a fifth resistor, a first end of which is connected to the inhibit output terminal, and the other end of which is connected to the overvoltage protection terminal,
the second output end of the second resistor is grounded, the other end of the second resistor is grounded, the dimming input end is empty, the other end of the third capacitor is grounded, and the second output end is used as an output negative electrode of the LED load.
6. The LED low voltage driving circuit according to claim 1, further comprising:
a fourth capacitor connected in series with the energy storage filter inductor, one end of the fourth capacitor being connected to the first output end, the other end of the fourth capacitor being connected to one end of the energy storage filter inductor, the other end of the energy storage filter inductor being connected to the switch end, the other end of the fourth capacitor being determined as an output negative electrode of the LED load, the fourth capacitor being configured to step down the constant current voltage,
the other end of the second resistor is grounded, the other end of the second capacitor is grounded, the dimming input end is connected with a fifth capacitor in series and then grounded, the grounding end is empty, the switch end is also connected with the fifth capacitor in series and then grounded, and the other end of the third capacitor is grounded.
7. The LED low voltage driving circuit according to claim 1, further comprising:
the fourth capacitor is arranged in parallel with the energy storage filter inductor and is used for boosting or reducing the constant-current voltage;
a fifth resistor, a first end of which is connected to the inhibit output terminal, and the other end of which is connected to the overvoltage protection terminal,
the other end of the second resistor, the other end of the second capacitor and the other end of the third capacitor are respectively connected to the second output end, the dimming input end is connected with the fifth capacitor in series and then connected to the second output end, and the first output end is determined to be an output negative electrode of the LED load.
8. The LED low voltage driver circuit of claim 5, wherein said filter module further comprises:
and one end of the sixth capacitor is connected to the first output end, and the other end of the sixth capacitor is connected to the second output end.
9. The LED low voltage driving circuit according to any one of claims 1 to 4, wherein the filtering module further comprises:
and the anode of the electrolytic capacitor is connected to the first output end, and the cathode of the electrolytic capacitor is connected to the second output end.
10. The LED low voltage driver circuit of claim 1, wherein the LED load is an MR16LED spotlight.
11. An LED light fixture, comprising:
the LED low voltage driving circuit according to any one of claims 1 to 10.
CN201810014841.6A 2018-01-08 2018-01-08 LED low-voltage driving circuit and LED lamp Active CN108024420B (en)

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CN109041343A (en) * 2018-08-06 2018-12-18 广东德洛斯照明工业有限公司 A kind of LED drive circuit of low electromagnetic
CN108922480B (en) * 2018-09-27 2024-04-02 广州视源电子科技股份有限公司 LED current-sharing control circuit
CN109587894B (en) * 2019-01-09 2024-03-05 浙江阳光美加照明有限公司 Wireless control linear driving circuit of LED filament lamp

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CN202634816U (en) * 2012-05-25 2012-12-26 无锡实益达电子有限公司 Small-size low-electromagnetic-interference LED (light emitting diode) driving power supply
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