CN111315076A - LED power supply system and device - Google Patents

LED power supply system and device Download PDF

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Publication number
CN111315076A
CN111315076A CN202010205210.XA CN202010205210A CN111315076A CN 111315076 A CN111315076 A CN 111315076A CN 202010205210 A CN202010205210 A CN 202010205210A CN 111315076 A CN111315076 A CN 111315076A
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China
Prior art keywords
circuit
power supply
led
output
feedback
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CN202010205210.XA
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Chinese (zh)
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CN111315076B (en
Inventor
胡向峰
盘桥富
鲍晓杰
李亚伟
黄德强
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Shenzhen Skyworth RGB Electronics Co Ltd
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Shenzhen Skyworth RGB Electronics Co Ltd
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Priority to CN202010205210.XA priority Critical patent/CN111315076B/en
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00Conversion of dc power input into dc power output

Abstract

The invention discloses an LED power supply system, which comprises an electromagnetic interference EMI circuit, a rectifying circuit, a power factor correction PFC circuit and a double-feedback power supply system circuit; the double-feedback power supply system circuit comprises an LED control circuit and a feedback sub-circuit; the feedback sub-circuit comprises a main feedback sub-circuit and a secondary feedback sub-circuit; the main feedback sub-circuit is used for adjusting the output voltage of the LED control circuit according to the voltage of the LED lamp and the feedback of the secondary feedback sub-circuit. The invention also discloses a device of the LED power supply system. The invention can adjust the power supply voltage of the LED lamp in the LED power supply system.

Description

LED power supply system and device
Technical Field
The invention relates to the technical field of display, in particular to an LED power supply system and device.
Background
With the coming of the LED era, the application of LEDs is more and more extensive, especially, a Mini-LED or a Micro-LED is used as a backlight source display of a high-power product, regional dimming in a smaller range is realized through a large number of small-distance lamp beads, and because the number of backlight lamp beads is large, the power supply power is large and automatic control and adjustment cannot be carried out, the loss of devices in an LED circuit is large, and the service life of the LED product is not long.
Disclosure of Invention
The invention mainly aims to provide an LED power supply system and an LED power supply device, and aims to solve the problem of loss in the application of the LED power supply system.
In order to achieve the above object, the present invention provides an LED power system, which includes an electromagnetic interference EMI circuit, a rectifier circuit, a power factor correction PFC circuit, and a dual feedback power system circuit;
the double-feedback power supply system circuit comprises an LED control circuit and a feedback sub-circuit;
the feedback sub-circuit comprises a main feedback sub-circuit and a secondary feedback sub-circuit;
the input end of the electromagnetic interference EMI circuit is connected with an external power supply, the output end of the electromagnetic interference EMI circuit is connected with the input end of the rectifying circuit, the output end of the rectifying circuit is connected with the input end of the power factor correction PFC circuit, the output end of the power factor correction PFC circuit is connected with the input end of the LED control circuit, the output end of the LED control circuit is connected with the main feedback sub-circuit, the output end of the main feedback sub-circuit is connected with the input end of the secondary feedback sub-circuit, and the output end of the secondary feedback sub-circuit is connected with an LED lamp;
the electromagnetic interference EMI circuit is used for filtering electromagnetic interference signals of the external power supply;
the rectification circuit is used for converting alternating current output by the electromagnetic interference EMI circuit into direct current;
the Power Factor Correction (PFC) circuit is used for converting the direct current output by the rectifying circuit into stable direct current and outputting the stable direct current to the LED control circuit;
the main feedback sub-circuit is used for adjusting the output voltage of the LED control circuit according to the voltage of the LED lamp and the feedback of the secondary feedback sub-circuit.
Optionally, the LED control circuit comprises:
a resonant circuit LLC sub-circuit and a synchronous rectifier sub-circuit;
the input end of the resonant circuit LLC sub-circuit is connected with the output end of the power factor correction PFC circuit, the output end of the resonant circuit LLC circuit is connected with the input end of the synchronous rectifier sub-circuit, and the output end of the synchronous rectifier sub-circuit is connected with the external LED lamp;
the resonant circuit LLC sub-circuit is used for adjusting the output voltage of the power factor correction PFC circuit to a required direct-current voltage;
and the synchronous rectifier sub-circuit is used for rectifying the direct current in the resonant circuit LLC sub-circuit and then outputting the rectified direct current.
Optionally, the secondary feedback sub-circuit comprises:
a feedback FB pin circuit;
the input end of the feedback FB pin circuit is connected with the external LED, and the output end of the feedback FB pin circuit is connected with the main feedback circuit;
the feedback FB pin circuit is used for detecting the voltage difference of the external LED lamp.
Optionally, the LED power supply system comprises:
a filter circuit;
the input end of the filter circuit is connected with the output end of the rectification circuit, and the output end of the filter circuit is connected with the input end of the Power Factor Correction (PFC) circuit;
the filter circuit is used for filtering the ripple of the output voltage of the rectifying circuit.
Optionally, the LED power supply system comprises:
the main board and the logic board TCON circuit;
the input end of the main board and logic board TCON circuit is electrically connected with the PFC circuit, the first output end of the main board and logic board TCON circuit is connected with the logic board TCON, the second output end of the main board and logic board TCON circuit is connected with the power amplifier circuit, and the third output end of the main board and logic board TCON circuit is connected with the main board circuit;
the main board circuit adjusts the main board and the logic board TCON circuit through a feedback circuit;
the main board and the logic board TCON circuit are used for providing required voltage for the main board circuit, the logic board TCON circuit and the power amplifier circuit.
Optionally, the LED power supply system comprises:
a standby circuit;
the input end of the standby circuit is electrically connected with the PFC circuit, the first output end of the standby circuit is connected with the constant current chip of the external LED lamp for power supply, and the second output end of the standby circuit is connected with the main chip of the mainboard for power supply;
the constant current chip of the external LED lamp is used for controlling the current value of the external LED lamp;
and the main chip of the mainboard is used for controlling the operation of the power supply system.
Optionally, the logic board TCON circuit further includes:
a logic board TCON switching circuit;
the input end of the logic board TCON switching circuit is electrically connected with the main board and the TCON board circuit, the output end of the logic board TCON switching circuit is electrically connected with the logic board TCON circuit, and the enabling end of the logic board TCON switching circuit is electrically connected with the main board circuit;
the logic board TCON switching circuit is used for controlling the on and off of the logic board TCON circuit.
Optionally, the main board and logic board TCON circuit further includes:
a timing control circuit;
the time sequence control circuit is formed by connecting an enabling end of the mainboard circuit with enabling ends of all circuit devices of the power supply system;
the time sequence control circuit controls the on-off of each device in the power supply system according to time sequence through an enabling signal sent by an enabling end of the mainboard.
Optionally, the LED power supply system comprises:
a thermistor switching circuit;
the input end of the thermistor switching circuit is connected with the external power supply, and the output end of the thermistor switching circuit is connected with the input end of the electromagnetic interference EMI circuit;
the thermistor switching circuit is used for adjusting the input current of the external power supply.
In addition, to achieve the above object, the present invention further provides an apparatus of an LED power supply system, including: an LED power system circuit capable of executing the circuitry of the LED power system.
According to the LED power supply system, the power supply voltage of the LED lamps in the LED power supply system circuit is adjusted through the double-feedback power supply system circuit, so that the power supply voltage of the LED lamps is adjusted according to the voltage difference of the LED lamps in the LED power supply system, the loss of the LED lamps is reduced, and the service life of the LED lamps is prolonged.
Drawings
FIG. 1 is a logic structure diagram of a first embodiment of an LED power system according to the present invention;
FIG. 2 is a logic structure diagram of a second embodiment of the LED power system of the present invention;
FIG. 3 is a logic structure diagram of the secondary feedback sub-circuit 1422 of the present invention;
FIG. 4 is a schematic diagram of the primary and secondary feedback circuits of the feedback sub-circuit 142 of the present invention;
FIG. 5 is a logic structure diagram of the timing control circuit 80 according to the present invention;
FIG. 6 is a logic diagram of the sequential control of the timing control circuit 80 according to the present invention;
FIG. 7 is a schematic circuit diagram of a thermistor switching circuit 90 according to the present invention;
fig. 8 is a schematic diagram of a power supply circuit of the LED power supply system of the present invention.
The implementation, functional features and advantages of the objects of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The main solution of the embodiment of the invention is as follows:
because the existing LED power supply adopts the independent module power supply combination to supply power, the module power supplies are mutually independent, and the constant current control circuit of the LED lamp does not participate in the power supply feedback regulation, the power supply system is complex, the efficiency is low, and the current heat loss is large.
According to the solution provided by the invention, the power supply voltage of the LED lamp in the LED power supply system circuit is adjusted through the double-feedback power supply system circuit, so that the power supply voltage of the LED lamp is adjusted according to the difference of the LED lamp in the LED power supply system, the service life of the LED lamp is prolonged, and the loss of the LED lamp is reduced.
Referring to fig. 1, a first embodiment of the LED power supply system of the present invention provides a logical structure diagram of an LED power supply system, including: an electromagnetic interference (emi) (electromagnetic interference) circuit 11, a rectifier circuit 12, a power Factor correction (pfc) (power Factor correction) circuit 13, and a dual feedback power system circuit 14; LLC circuit: resonant circuit
The dual feedback power supply system circuit 14 includes an LED control circuit 141 and a feedback sub-circuit 142;
the feedback sub-circuit 142 includes a primary feedback sub-circuit 1421 and a secondary feedback sub-circuit 1422;
the input end of the electromagnetic interference EMI circuit 11 is connected to an external power supply 10, the output end of the electromagnetic interference EMI circuit 11 is connected to the input end of the rectifier circuit 12, the output end of the rectifier circuit 12 is connected to the input end of the power factor correction PFC circuit 13, the output end of the power factor correction PFC circuit 13 is connected to the input end of the LED control circuit 141, the output end of the LED control circuit 141 is connected to the primary feedback sub-circuit 1421, the output end of the primary feedback sub-circuit 1421 is connected to the input end of the secondary feedback sub-circuit 1422, and the output end of the secondary feedback sub-circuit 1422 is connected to the LED lamp 15;
the electromagnetic interference EMI circuit 11 is used for filtering electromagnetic interference signals of the external power supply;
the rectifying circuit 12 is used for converting the alternating current output by the electromagnetic interference EMI circuit 11 into direct current;
the PFC circuit 13 is configured to convert the dc power output by the rectifying circuit 12 into a stable dc power and output the stable dc power to the LED control circuit 141;
the primary feedback sub-circuit 1421 is configured to adjust the output voltage of the LED control circuit 141 according to the voltage of the LED lamp 15 and the feedback sub-circuit 1422.
When the LED power system is connected to the stable external power source 10, the electrical signal of the external power source 10 filters the electromagnetic interference information in the circuit through the electromagnetic interference EMI circuit 12, the electrical signal with the electromagnetic interference signal filtered realizes the conversion of the alternating current signal into the direct current signal through the rectification circuit 12, although the direct current is converted into the direct current, the utilization rate of the electrical signal is not high, the rectified electrical signal needs to be further corrected by the PFC circuit 13, the utilization rate of the electrical signal is improved by the corrected electrical signal, so as to transmit the corrected electrical signal to the LED control circuit 141 and provide the corrected electrical signal to the LED lamp 15 for power supply, the powered LED lamp 15 will feed back the actual electrical information in the circuit to the LED control circuit 141 through the main feedback circuit 1421, thereby achieving the purpose that the LED control circuit 141 controls the LED lamp 15; however, due to certain differences among lamp beads of the LED lamps in actual production, the power supply voltage required by the actual LED lamps is different, if different LED lamps adopt uniform output voltage, part of the LED lamps will reduce the service life of the LED lamps due to overload, so the secondary feedback sub-circuit 1422 can further adjust the output voltage of the LED lamp 15 through the LED control circuit 141 by acquiring the difference information of the lamp beads of the LED lamp 15 and feeding the difference information back to the main feedback sub-circuit 1421 and then to the LED control circuit 141 through the secondary feedback sub-circuit 1422.
Therefore, the LED power supply system feeds data information in an actual circuit back to the LED control circuit in time through the primary feedback circuit and the secondary feedback circuit, so that the LED control circuit can properly adjust the power supply voltage of the LED, unnecessary loss of the LED lamp is reduced, and the service life of the LED lamp is prolonged.
Further, referring to fig. 2, the LED power system of the present invention provides a logic structure diagram of the LED power system of the second embodiment, based on the embodiment shown in fig. 2, the LED control circuit 141 includes: a resonant circuit LLC (a class of circuits in which there are two inductors (L) and a resonant capacitor (C)) sub-circuit 1411 and a synchronous rectifier sub-circuit 1412; the input end of the resonant circuit LLC sub-circuit 1411 is connected with the output end of the power factor correction PFC circuit 13, the output end of the resonant circuit LLC sub-circuit 1411 is connected with the input end of the synchronous rectifier sub-circuit 1412, and the output end of the synchronous rectifier sub-circuit 1412 is connected with the LED lamp 15;
the resonant circuit LLC sub-circuit 1411 is configured to adjust the output voltage of the PFC circuit 13 to a desired dc voltage;
the synchronous rectification sub-circuit 1412 is configured to rectify and output the direct current in the resonant circuit LLC sub-circuit 1411.
The LED control circuit 141 receives the electrical signal output by the PFC circuit 13, adjusts the corrected electrical signal to a desired dc signal through the LLC sub-circuit 1411, and converts the dc signal into a dc signal through the synchronous rectifier sub-circuit 1412, so as to improve the conversion efficiency of the electrical signal and reduce unnecessary power consumption, and the rectified electrical signal further adjusts the output voltage of the LED lamp 15 through the feedback circuit 142.
Specifically, the LED control circuit can be an LED lamp which is connected with the parallel control of a plurality of resonant circuit LLC sub-circuits and a synchronous rectifier sub-circuit, and the grouped LED lamps are regulated and controlled by the corresponding one-to-one regulation and control of the plurality of resonant circuit LLC sub-circuits and the feedback sub-circuits respectively by grouping the LED lamps, so that one access power supply separately controls the plurality of parallel LED control circuits, the design of a plurality of power supply modules of the conventional LED power supply system is optimized, the working efficiency of the power supply system is improved, and the heat loss of the LED power supply system is reduced; in addition, each group of the LED lamps is controlled by a separate LED control circuit, the separate LED control circuits are mutually independent, and compared with the existing LED lamp unified low-voltage control, the separate control of the LED control circuits controls the LED lamp groups, so that the current of the LED lamp groups is reduced, the heat loss of the LEDs is reduced, and the purpose of prolonging the service life of the LEDs is realized. TCON board: timing Controller logic board
The embodiment adopts the synchronous rectification circuit to improve the conversion efficiency of the medium electric signal of the LED control circuit, and further reduces the loss of the LED power supply system circuit. In addition, the rectifier diode having the rectifying function can be replaced with a synchronous rectifier circuit according to the needs of the power supply system, and a schottky diode and the like are commonly included. PS _ ON: POWER Supply-ON
Further, referring to fig. 3, the LED power system of the present invention provides a logical structure diagram of the sub-feedback sub-circuit 1422, and based on the embodiment shown in fig. 1 or fig. 2, the sub-feedback sub-circuit 1422 includes: a feedback fb (feed back) pin circuit 1422-1; the input end of the feedback FB pin sub-circuit 1422-1 is connected to the external LED lamp 15, and the output end of the feedback FB pin sub-circuit 1422-1 is connected to the main feedback circuit 1421;
the feedback FB pin circuit 1422-1 is configured to detect a voltage difference of the external LED lamp 15.
When the voltage difference exists between the lamp beads in the LED lamp 15, the constant current detection chip in the FB pin sub-circuit can detect the voltage difference between different lamp beads, so as to generate a current, and the generated current is communicated with the secondary feedback sub-circuit 1422, so that the current information in the secondary feedback sub-circuit 1422 is fed back to the main feedback circuit 1421 to generate the voltage difference, for example, the set voltage value of the main feedback sub-circuit is 2.5V, and when the voltage value in the main feedback sub-circuit is detected to be greater than the set value, a signal is fed back to the LED control circuit through the main feedback sub-circuit, so as to adjust the output voltage of the LED control circuit, thereby implementing the required voltage regulation and control of different LEDs.
Specifically, the actual working principle of the double-feedback power supply circuit of the LED power supply system can refer to fig. 4, and the feedback circuit is composed of an optical coupler (optical coupler is also called as a photoelectric isolator or a photoelectric coupler) U0, an optical coupler power supply resistor R15, a shunt resistor R16, an adjustable voltage regulator (adjustable dc voltage regulator) U10 (generally TL431, a controllable precise voltage regulator), a compensation circuit C11/R14/C10, and a sampling resistor R11/R12/R13. The primary sampling circuit of Vout (output voltage) is formed by R13/R12/R11, is used for adjusting the output voltage Vout of the LLC circuit, and the secondary feedback sampling circuit is formed by FB current signals from the LED lamp and R10/R11. When the current in the feedback FB circuit flows into the main feedback circuit through R10 due to the difference of the lamp beads, the voltage of VFB (feedback voltage) is increased, and in order to ensure that the voltage of Vref (reference voltage) is 2.5V, the feedback circuit adjusts the LLC output of the main circuit, so that the voltage of Vout is increased, and the normal work of the lamp beads on the lamp panel is ensured. When the difference of the lamp beads is larger, the current flowing into a VFB point is larger, the voltage of Vout is higher, the output voltage Vout of the power supply is adjusted along with the change of the difference of the matched lamp beads, so that the voltage output caused by the difference of different LED lamp beads is optimal, the heat loss of constant current chips on different LED lamps caused by the difference of the lamp beads is reduced, the loss of the LED lamps is reduced, and the service life of the LED lamps is prolonged.
If there is no feedback FB sub-circuit to sample, when the power supply system is designed, the output voltage Vout needs to be designed according to the highest lamp bead voltage, if the lamp bead voltage is lower, the same power supply output voltage, because the lamp bead current is constant, the heat loss of the constant current chip on the screen body with lower lamp bead voltage will be increased, and when the LED lamps are grouped more, the whole LED backlight control loss is increased sharply.
Therefore, an FB signal in the secondary feedback FB sub-circuit is connected to the VFB through the R10, the VFB is connected with the Vref through the resistor R12, and a voltage difference is generated at two ends of the resistor R12, so that the main feedback circuit feeds back information to the LED control circuit, the output voltage of the resonant LLC sub-circuit and the rectifying circuit is further regulated, and the current of the feedback FB sub-circuit plays a secondary regulation role on the main feedback sub-circuit; if the FB signal in the secondary feedback FB sub-circuit is directly connected to Vref through R10, the primary feedback sub-circuit of Vout1 is greatly adjusted, and when the difference of lamp beads is large, Vout output is greatly changed, so that the stability of the whole circuit is influenced; therefore, the secondary feedback FB sub-circuit not only ensures that the output of the main feedback circuit is not influenced, but also can properly adjust the LED power supply voltage according to the voltage of the lamp bead, and the heat loss of the LED lamp bank is reduced.
Further, based on the embodiment shown in fig. 2, the LED power supply system includes: a filter circuit 40; the input end of the filter circuit 40 is connected with the output end of the rectifying circuit 12, and the output end of the filter circuit 40 is connected with the input end of the power factor correction PFC circuit 13;
the filter circuit 40 is used for filtering the ripple of the output voltage of the rectifier circuit.
In this embodiment, the filter circuit 40 filters the ac component in the electrical signal output by the rectifier circuit 12, and retains the dc component, so that the ripple coefficient of the output voltage is reduced, the waveform becomes smoother, and the smoothed electrical signal is further input to the power factor correction PFC circuit, thereby being beneficial to the normal operation of subsequent dc circuit devices. Common filter circuits include two major types, passive filter and active filter; the filter circuit elements of the passive filter circuit only consist of passive elements (resistors, capacitors and inductors), and the main forms of passive filtering include capacitor filtering, inductor filtering and duplex filtering (including inverted L-type, LC filtering, LC pi-type filtering, RC pi-type filtering and the like); the filter circuit elements of the active filter circuit include passive elements and active elements (bipolar type tubes, unipolar type tubes, integrated operational amplifiers), and active RC filters, i.e. electronic filters, are commonly used.
Further, based on the embodiment shown in fig. 2, the LED power supply system includes: a main board and logic board TCON circuit 50; the input end of the main board and logic board TCON circuit 50 is electrically connected to the PFC circuit 13, the first output end of the main board and logic board TCON circuit 50 is connected to the logic board TCON circuit 52, the second output end of the main board and logic board TCON circuit 50 is connected to the power amplifier circuit 51, and the third output end of the main board and logic board TCON circuit 50 is connected to the main board circuit 53;
the main board circuit 53 adjusts the main board and logic board TCON circuit to supply the main board circuit with stable voltage through the feedback circuit 1 (54);
the main board and logic board TCON circuit 50 is used to provide the required voltage for the main board circuit 53, the logic board TCON circuit 52 and the power amplifier circuit 51.
When the main board and logic board TCON circuit receives the correction electrical signal provided by the PFC circuit, the main board and the logic board TCON circuit for receiving the correction signal adopt LLC circuit, the LLC circuit includes half-bridge resonant circuit, for example, when the LLC circuit can provide 20V voltage for the power amplifier circuit, the LLC circuit can provide 12V stable voltage for the motherboard, and a feedback circuit regulates 1(54) to control the output of the stable voltage, the LLC circuit can provide 12V voltage for the logic board TCON circuit, the values of the stable voltage listed in the embodiment can be adjusted and controlled according to the actual needs of the LED power supply system, the main board and the logic board TCON circuit provide the basis for the logic processing of the LED system and the function logic operation of the whole system, so that the normal operation of each function of the LED power supply system is guaranteed.
Further, based on the embodiment shown in fig. 2, the LED power supply system includes: a standby circuit 60; the input end of the standby circuit 60 is connected with the output end of the power factor correction PFC circuit 13, the first output end of the standby circuit 60 is connected with the constant current chip 62 of the LED lamp for power supply, and the second output end of the standby circuit 60 is connected with the main chip 61 of the mainboard for power supply;
the constant current chip 62 of the LED lamp is used for controlling the current value of the LED lamp 15;
the main chip 61 of the motherboard is used to control the operation of the power system.
When the LED power system receives a high level signal, the PFC circuit 13 inputs an electrical signal to the standby circuit 60, the standby circuit 60 outputs a stable voltage through voltage transformation, for example, 5VSB (auxiliary power supply) voltage is output to supply power to a main chip 61 on the main board circuit, 5V is supplied power to a constant current chip 62 on the LED lamp, and the stable voltage 5V output is fed back to output a stable voltage through a feedback circuit 2 (63); the output magnitude of the stable voltage can be adjusted and controlled according to the requirements of the LED power supply system; the standby circuit supplies power to the mainboard and the LED constant current chip to start running when the LED power supply system is started.
Further, based on the embodiment shown in fig. 2, the logic board TCON circuit further includes: a logic board TCON switching circuit 70; the input end of the logic board TCON switching circuit 70 is electrically connected to the main board and the TCON board circuit 50, the output end of the logic board TCON switching circuit 70 is electrically connected to the logic board TCON circuit 52, and the enable end of the logic board TCON switching circuit 52 is electrically connected to the main board circuit 53;
the logic board TCON switching circuit 70 is used for controlling the logic board TCON circuit 52 to be turned on and off.
After the LED power system is started, the main board circuit generates a high level signal and sends a logic enable TCON _ EN signal, and the logic enable TCON _ EN signal controls the logic board TCON switching circuit 70 to further control the logic board TCON circuit to be started; if the main board circuit sends out a low level signal, the output of the logic enable TCON _ EN signal is suspended, and the logic board TCON switching circuit 70 further controls the logic board TCON circuit to be turned off.
Further, referring to fig. 5, based on the embodiment shown in fig. 2, the main board and logic board TCON circuit further includes: a timing control circuit 80; the timing control circuit is formed by connecting an enabling end 801 of the mainboard circuit with an enabling end 802 of each circuit device 803 of the power supply system;
the timing control circuit controls the opening and closing of each circuit device 803 in the power supply system according to the timing through an enabling signal sent by an enabling end 801 of the mainboard.
Specifically, referring to fig. 6, when the LED POWER system is turned ON, the main board circuit 53 is powered ON and sends a high level signal PS _ ON (POWER Supply-ON), after sending a PS _ ON high electrical signal for t1 time, the main board circuit then sends a logic Enable TCON _ EN (TCON-Enable) signal, after t2 time, the main board circuit sends a backlight constant current dimming signal pwm (pulse width modulation), and after t3 time, the main board circuit sends a backlight control Enable signal (ENA), and after that, the backlight system operates normally, and the LED lamp is turned ON. When the LED power system receives a standby signal, the main board turns off ENA, PWM and TCON _ EN after t4, t5 and t6 in sequence, and finally PS _ ON is changed into low level, and the whole machine enters a standby state, so that the time sequence control of the power system is realized; meanwhile, the enabling signal of the mainboard circuit controls the on-off of each circuit device in the power supply system instead of being directly controlled by the input of an external power supply, so that the noise of circuit switching and the heat loss of the circuit devices caused by the on-off of the power supply are avoided, and meanwhile, the sequential control circuit realizes that the LED equipment has the characteristic of an intelligent network standby system.
Further, referring to fig. 7, the present invention provides a schematic circuit diagram of a thermistor switching circuit 90, and based on the embodiment shown in fig. 2, the LED power supply system includes: a thermistor switching circuit 90; the input end of the thermistor switching circuit 90 is connected with the external power supply 10, and the output end of the thermistor switching circuit 90 is connected with the input end of the electromagnetic interference EMI circuit 11;
the thermistor switching circuit 90 is used for adjusting the input current of the external power supply.
Referring to fig. 7, after the LED power system is turned on, according to the sequence of power system timing control, when the main board circuit sends out a logic enable TCON _ EN high level signal, after voltage division by R30 and R31 resistors, the Q30 triode is turned on, the base of the Q31 triode is at a low level, the Q31 triode is turned on, 5VSB (auxiliary power supply) supplies power to the relay K0 through the resistor R33, the K0 is turned on, the relay spring is attracted, the point a and the point B are turned on, the thermistor is short-circuited at this time, thereby preventing the temperature rise from being too high due to long-time operation, in the t1 time period, the relay is not turned on, the thermistor operates, the surge current in the power-on instant circuit is suppressed, and the rear-stage device is protected; according to the sequence requirement of the time sequence control signal, the temperature rise of the thermistor after the LED display device is started is solved, and the switching noise problem when the whole network is in standby is avoided, so that the problems of low-voltage heat loss of the thermistor in the high-power LED display device and switching circuit noise are solved.
Specifically, referring to fig. 8, the power supply condition of the power system circuit can be further understood, after the external power source is powered ON, the standby circuit in the power system starts to operate, and outputs +5VSB to power the main board circuit, after that, the main board circuit sends out a high level signal PS _ ON, the circuit starts to operate, and the PS _ ON high level signal starts to operate
In addition, the specific embodiment of the LED power system device of the present invention is substantially the same as the embodiments of the LED power system circuit described above, and is not described herein again.
It is further noted that, herein, relational terms such as first, second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the present specification and drawings, or used directly or indirectly in other related fields, are included in the scope of the present invention.

Claims (10)

1. An LED power supply system is characterized by comprising an electromagnetic interference EMI circuit, a rectifying circuit, a power factor correction PFC circuit and a double-feedback power supply system circuit;
the double-feedback power supply system circuit comprises an LED control circuit and a feedback sub-circuit;
the feedback sub-circuit comprises a main feedback sub-circuit and a secondary feedback sub-circuit;
the input end of the electromagnetic interference EMI circuit is connected with an external power supply, the output end of the electromagnetic interference EMI circuit is connected with the input end of the rectifying circuit, the output end of the rectifying circuit is connected with the input end of the power factor correction PFC circuit, the output end of the power factor correction PFC circuit is connected with the input end of the LED control circuit, the output end of the LED control circuit is connected with the main feedback sub-circuit, the output end of the main feedback sub-circuit is connected with the input end of the secondary feedback sub-circuit, and the output end of the secondary feedback sub-circuit is connected with the LED lamp;
the electromagnetic interference EMI circuit is used for filtering electromagnetic interference signals of the external power supply;
the rectification circuit is used for converting alternating current output by the electromagnetic interference EMI circuit into direct current;
the Power Factor Correction (PFC) circuit is used for converting the direct current output by the rectifying circuit into stable direct current and outputting the stable direct current to the LED control circuit;
the main feedback sub-circuit is used for adjusting the output voltage of the LED control circuit according to the voltage of the LED lamp and the feedback of the secondary feedback sub-circuit.
2. The LED power supply system of claim 1 wherein the LED control circuit comprises:
a resonant circuit LLC sub-circuit and a synchronous rectifier sub-circuit;
the input end of the resonant circuit LLC sub-circuit is connected with the output end of the power factor correction PFC circuit, the output end of the resonant circuit LLC circuit is connected with the input end of the synchronous rectifier sub-circuit, and the output end of the synchronous rectifier sub-circuit is connected with the external LED lamp;
the resonant circuit LLC sub-circuit is used for adjusting the output voltage of the power factor correction PFC circuit to a required direct-current voltage;
and the synchronous rectifier sub-circuit is used for rectifying the direct current in the resonant circuit LLC sub-circuit and then outputting the rectified direct current.
3. The LED power supply system of claim 1 wherein said secondary feedback sub-circuit comprises:
a feedback FB pin circuit;
the input end of the feedback FB pin circuit is connected with the external LED, and the output end of the feedback FB pin circuit is connected with the main feedback circuit;
the feedback FB pin circuit is used for detecting the voltage difference of the external LED lamp.
4. The LED power supply system of claim 1, wherein the LED power supply system comprises:
a filter circuit;
the input end of the filter circuit is connected with the output end of the rectification circuit, and the output end of the filter circuit is connected with the input end of the Power Factor Correction (PFC) circuit;
the filter circuit is used for filtering the ripple of the output voltage of the rectifying circuit.
5. The LED power supply system of claim 1, wherein the LED power supply system comprises:
the main board and the logic board TCON circuit;
the input end of the main board and logic board TCON circuit is electrically connected with the PFC circuit, the first output end of the main board and logic board TCON circuit is connected with the logic board TCON, the second output end of the main board and logic board TCON circuit is connected with the power amplifier circuit, and the third output end of the main board and logic board TCON circuit is connected with the main board circuit;
the main board circuit adjusts the main board and the logic board TCON circuit through a feedback circuit;
the main board and the logic board TCON circuit are used for providing required voltage for the main board circuit, the logic board TCON circuit and the power amplifier circuit.
6. The LED power supply system of claim 1, wherein the LED power supply system comprises:
a standby circuit;
the input end of the standby circuit is electrically connected with the Power Factor Correction (PFC) circuit, the first output end of the standby circuit is connected with the constant current chip of the external LED lamp for power supply, and the second output end of the standby circuit is connected with the main chip of the mainboard for power supply;
the constant current chip of the external LED lamp is used for controlling the current value of the external LED lamp;
and the main chip of the mainboard is used for controlling the operation of the power supply system.
7. The LED power system of claim 5, wherein the logic board TCON circuit further comprises:
a logic board TCON switching circuit;
the input end of the logic board TCON switching circuit is electrically connected with the main board and the TCON board circuit, the output end of the logic board TCON switching circuit is electrically connected with the logic board TCON circuit, and the enabling end of the logic board TCON switching circuit is electrically connected with the main board circuit;
the logic board TCON switching circuit is used for controlling the on and off of the logic board TCON circuit.
8. The LED power system of claim 5, wherein the main board and logic board TCON circuit further comprises:
a timing control circuit;
the time sequence control circuit is formed by connecting an enabling end of the mainboard circuit with an enabling end of a circuit device of the power supply system;
the time sequence control circuit controls the opening and closing of circuit devices in the power supply system according to time sequence through an enabling signal sent by an enabling end of the mainboard.
9. The LED power supply system of claim 1, wherein the LED power supply system comprises:
a thermistor switching circuit;
the input end of the thermistor switching circuit is connected with the external power supply, and the output end of the thermistor switching circuit is connected with the input end of the electromagnetic interference EMI circuit;
the thermistor switching circuit is used for adjusting the input current of the external power supply.
10. An apparatus of an LED power system, the apparatus of the LED power system comprising: an LED power system circuit;
the LED power supply system circuit is capable of executing the circuit of the LED power supply system of any one of claims 1 to 9.
CN202010205210.XA 2020-03-24 2020-03-24 LED power supply system and device Active CN111315076B (en)

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Citations (6)

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Publication number Priority date Publication date Assignee Title
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WO2013159371A1 (en) * 2012-04-28 2013-10-31 深圳市华星光电技术有限公司 Led backlight drive circuit, liquid crystal display device and drive method
CN104010148A (en) * 2014-05-26 2014-08-27 深圳创维-Rgb电子有限公司 Power circuit and television
CN109151351A (en) * 2018-09-25 2019-01-04 深圳创维-Rgb电子有限公司 A kind of power panel and TV
CN110391751A (en) * 2019-08-06 2019-10-29 深圳创维-Rgb电子有限公司 Double feedback digital power circuits and power supply

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202178046U (en) * 2011-07-26 2012-03-28 青岛海信电器股份有限公司 Backlight drive circuit and television set
US20130113841A1 (en) * 2011-11-08 2013-05-09 Ds Electron Co., Ltd. Backlight unit and display device including the same
WO2013159371A1 (en) * 2012-04-28 2013-10-31 深圳市华星光电技术有限公司 Led backlight drive circuit, liquid crystal display device and drive method
CN104010148A (en) * 2014-05-26 2014-08-27 深圳创维-Rgb电子有限公司 Power circuit and television
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