WO2014183329A1 - 一种过压保护电路、过压保护方法及面板驱动电路 - Google Patents

一种过压保护电路、过压保护方法及面板驱动电路 Download PDF

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Publication number
WO2014183329A1
WO2014183329A1 PCT/CN2013/078484 CN2013078484W WO2014183329A1 WO 2014183329 A1 WO2014183329 A1 WO 2014183329A1 CN 2013078484 W CN2013078484 W CN 2013078484W WO 2014183329 A1 WO2014183329 A1 WO 2014183329A1
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Prior art keywords
main
voltage
resistor
overvoltage protection
slave
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PCT/CN2013/078484
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English (en)
French (fr)
Inventor
张华�
杨翔
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TCL China Star Optoelectronics Technology Co Ltd
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Shenzhen China Star Optoelectronics Technology Co Ltd
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Priority to US14/008,075 priority Critical patent/US9401600B2/en
Publication of WO2014183329A1 publication Critical patent/WO2014183329A1/zh
Anticipated expiration legal-status Critical
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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • H05B45/52—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits in a parallel array of LEDs
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G09G3/3426—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines the different display panel areas being distributed in two dimensions, e.g. matrix
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/20—Responsive to malfunctions or to light source life; for protection
    • H05B47/24—Circuit arrangements for protecting against overvoltage
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/04—Display protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/041—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using a short-circuiting device
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • H05B45/54—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits in a series array of LEDs
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Definitions

  • Overvoltage protection circuit Overvoltage protection circuit, overvoltage protection method and panel drive circuit
  • the present invention relates to an overvoltage protection circuit, a protection method, and a panel drive circuit, and more particularly to a circuit and a protection method for overvoltage protection of an LED string by an overvoltage trigger circuit of a master-slave IC, and The panel drive circuit of the voltage protection circuit.
  • the number of channels of a single LED constant current driver IC (the number of LED strings that can be driven) is limited.
  • One of the ICs needs to provide a driving signal to the MOS transistor, so that the entire circuit can work normally. This IC is called the main IC, and other ICs only need to provide the dimming pin that connects the LED strings. These ICs are called slave ICs. .
  • the circuit of the traditional multiple IC master-slave mode connection is shown in Figure 1.
  • the output overvoltage protection point of each IC needs to be set by the voltage divider resistor. If the output overvoltage protection point of each IC is set to the same, Depending on the resistance accuracy or individual IC differences, the voltage value that triggers each IC overvoltage protection during actual operation may vary, and the IC may not trigger the protection function.
  • the output voltage is determined only by the drive signal output from the main IC. If the overvoltage protection trigger voltage value of the main IC is less than the trigger voltage value of the slave IC, when the LED is connected to the slave IC. The string appears open circuit, the output voltage is controlled by the main IC and rises. After reaching the overvoltage protection trigger point of the main IC, it stops rising. At this time, the main IC overvoltage protection function is triggered to start detecting the LED strings connected with the main IC; However, since the IC has a large voltage value due to overvoltage protection, it cannot trigger its own overvoltage protection function, which causes the LED string that cannot open the circuit to be closed from the IC. The main IC control output voltage is always maintained at a high voltage state, and the entire line is not stable.
  • the main object of the present invention is to provide an overvoltage protection circuit capable of separately controlling the voltage of the LED string by the master-slave IC, so that the output voltage protection function of the master-slave IC occurs when an abnormal condition occurs. Can play a role.
  • Another object of the present invention is to provide an overvoltage protection method with the overvoltage protection circuit.
  • Another object of the present invention is to provide a panel driving circuit with the overvoltage protection circuit.
  • the present invention provides an overvoltage protection circuit for regulating the voltage of a driving output terminal of a LED string with a main IC and a slave IC, which includes a main IC overvoltage trigger circuit and a slave IC overvoltage trigger circuit, wherein:
  • the main IC overvoltage trigger circuit is electrically connected to the main IC and the plurality of LED strings, respectively, and the slave IC overvoltage trigger circuit is respectively connected with the slave IC and the plurality of groups of LEDs. Connect, set the overvoltage protection trigger point in the main IC and the slave IC respectively, and the voltage of the overvoltage protection trigger point of the slave IC is lower than the voltage of the overvoltage protection trigger point of the main IC.
  • the minimum divided voltage on the slave IC overvoltage trigger circuit is greater than the maximum divided voltage of the main IC overvoltage trigger circuit.
  • the minimum divided voltage on the IC overvoltage trigger circuit is 0.7-1 V higher than the maximum divided voltage of the main IC overvoltage trigger circuit.
  • the main IC overvoltage trigger circuit includes at least two main voltage dividing resistors connected in series, and the slave IC overvoltage trigger circuit also includes at least two slave voltage dividing resistors connected in series, wherein, between the main voltage dividing resistors Set the overvoltage protection trigger point of the main IC, and set the overvoltage protection trigger point from the IC between the voltage divider resistors.
  • the main voltage dividing resistor comprises a first resistor and a second resistor, the first resistor is disposed between the overvoltage protection trigger point and the driving output end of the main IC, and the second resistor is disposed on the overvoltage protection trigger of the main IC.
  • the slave voltage dividing resistor includes a third resistor and a fourth resistor, the third resistor is disposed between the overvoltage protection trigger point of the slave IC and the driving output terminal, and the fourth resistor is disposed at an overvoltage of the slave IC Between the protection trigger point and the ground end, wherein a ratio of a fourth resistor from a voltage divider resistor to a sum of a resistance value of the third resistor and the fourth resistor is greater than a second resistor of the main divider resistor and the first resistor and the second resistor The ratio of the sum of the resistance values of the resistors.
  • the main voltage dividing resistor comprises a first resistor, a second resistor and a third resistor, and the first resistor and the second resistor are disposed between the overvoltage protection trigger point of the main IC and the driving output end, and the third resistor is set Between the overvoltage protection trigger point of the main IC and the ground terminal, the fourth resistor and the fifth resistor are disposed between the overvoltage protection trigger point and the driving output terminal of the IC, and the sixth resistor is set to the overvoltage protection of the slave IC.
  • a ratio of a sixth resistor from the voltage divider resistor to a sum of resistance values of the fourth resistor, the fifth resistor, and the sixth resistor is greater than a third resistor and a third resistor in the main divider resistor
  • the ratio of the sum of the resistance values of a resistor, a second resistor, and a third resistor may be equal to the resistance value of the sixth resistor.
  • the main IC includes an electrically connected main control module and a main detection module, and the main detection module is electrically connected to the main voltage dividing resistor to detect a voltage change of the main voltage dividing resistor, and the main control module and the LED string
  • the driving output end is electrically connected, and the voltage of the driving output end is adjusted according to the detection result of the main detecting module
  • the slave IC comprises an electrical connection slave control module and a slave detection module, and the slave detection module is electrically connected to the slave voltage dividing resistor Detecting the voltage change from the voltage dividing resistor, electrically connecting the control module from the driving output terminal, adjusting the voltage of the driving output terminal according to the detection result of the detecting module, as the output voltage rises, in the slave IC, when detecting from the slave
  • the module detects that the voltage from the voltage dividing resistor reaches the overvoltage protection trigger point of the IC, it sends a shutdown detection command from the control module to the LED string that has an open circuit, interrupting the voltage/current detection thereof
  • the main detection module is electrically connected to each LED string, and each LED string is connected in series with a current limiting resistor.
  • the main detection module detects that the current limiting resistor voltage value in a certain LED string circuit is higher than the set value, it is fed back to the main control module, and the main control module sends a shutdown detection command to the LED string, and the control is turned off.
  • the LED string is detected, and the output voltage of the LED string drive output is controlled to decrease;
  • the slave detection module is electrically connected to each LED string, and the LED strings are respectively connected in series with the current limiting resistor, when the slave detection module measures When the current limiting resistor in a certain LED string circuit is higher than the set value, it is fed back to the slave control module, and the slave module sends a close detection command to the LED string, and controls to turn off the detection of the corresponding LED string;
  • the main IC and the slave IC respectively perform negative feedback control on the on and off of each LED string.
  • the invention also provides an overvoltage protection method using the above-mentioned overvoltage protection circuit, which comprises the following steps: Step 1) setting the main IC and the slave IC in the main IC overvoltage trigger circuit and the slave IC overvoltage trigger circuit The overvoltage protection trigger point, the voltage of the overvoltage protection trigger point of the slave IC is lower than the voltage of the overvoltage protection trigger point of the main IC;
  • Step 2 As the output voltage rises, when the voltage from the voltage-receiving resistor is detected from the slave detection module of the IC, it is compared with the overvoltage protection trigger point from the IC:
  • a shutdown detection command is sent from the control module to the open LED string, and the current/voltage detection of the corresponding LED string is controlled to be turned off;
  • Step 3 When the main detection module of the main IC detects that the voltage on the main divider resistor is compared with the overvoltage protection trigger point of the main IC: If the voltage on the main divider resistor reaches the overvoltage protection trigger point of the main IC, the main The control module sends a shutdown command to the LED string that has an open circuit, controls the corresponding LED string to be turned off, and drives the output voltage to decrease;
  • Step 4) The main control module adjusts the voltage adjustment range of the LED drive output according to the feedback value of the main detection module. Step 41) When the main control module needs to increase the output voltage according to the feedback value of the main detection module, the main control module sends a boost control signal to the MOS tube, and the driving MOS tube increases the duty ratio to drive the LED driving output end. Voltage increase range;
  • Step 42) If it is necessary to reduce the output voltage, the main control module sends a buck control signal to the MOS transistor, and the driving MOS transistor reduces the duty ratio to drive the voltage drop of the LED driving output terminal.
  • the present invention also provides a panel driving circuit including an LED string with a main IC and a slave IC, and the above-described overvoltage protection circuit for adjusting the voltage of the driving output terminal of the LED string with the main IC and the slave IC.
  • the present invention provides an overvoltage protection circuit, a protection method, and a panel driving circuit thereof, wherein the overvoltage protection circuit respectively sets an overvoltage trigger circuit in the main IC and the slave IC, by changing the main IC and The connection ratio between the IC and the overvoltage trigger circuit, and the ratio of the divider resistors of the master and slave ICs, and the setting of the overvoltage protection trigger point from the IC is lower than that of the main IC, so that when an abnormal condition occurs, the output When the voltage rises, the IC triggers the output overvoltage protection function from the IC first to reflect the working status of the LED string in real time. If the overvoltage protection trigger point of the main IC is reached, it controls the voltage of the LED drive output terminal, causing the entire circuit to be in a regulated state.
  • DRAWINGS 1 is a circuit diagram of a conventional overvoltage protection circuit
  • FIG. 2 is a circuit block diagram of an overvoltage protection circuit of the present invention
  • FIG. 3 is a circuit diagram of an overvoltage protection circuit according to an embodiment of the present invention.
  • FIG. 4 is a circuit diagram of an overvoltage protection circuit according to Embodiment 2 of the present invention.
  • the present invention provides an overvoltage protection circuit for regulating the voltage of the driving output terminal 100 of the LED string 401, 402 with the main IC 202 and the slave IC 302, which includes the main IC overvoltage trigger circuit 201 and the overvoltage trigger from the IC.
  • the circuit 202 wherein: the main IC overvoltage trigger circuit 201 is electrically connected to the main IC 202 and the plurality of LED strings 401, respectively, and the slave IC overvoltage trigger circuit 201 is electrically connected to the slave IC 302 and the plurality of sets of LED strings 402, respectively.
  • the overvoltage protection trigger point is set in the main IC 202 and the slave IC 302, and the voltage of the overvoltage protection trigger point of the slave IC 302 is lower than the voltage of the overvoltage protection trigger point of the main IC 202.
  • the main IC 202 controls the on/off of the LED string 401 connected thereto according to the voltage change value fed back by the main IC overvoltage trigger circuit 201, and adjusts the magnitude of the output voltage;
  • the slave IC overvoltage trigger circuit 301 is connected to the slave IC 302, and Connected to a plurality of sets of LED strings 402, the IC 302 controls the on and off of the LED string 402 connected thereto according to the voltage change fed back from the IC overvoltage trigger circuit 301, so as to ensure that the LED drive output terminal 100 can be normally powered, and the output voltage is long. The time remains high and the entire circuit is unstable.
  • the main IC 202 includes an electrical control main control module 202a and a main detection module 202b.
  • the main detection module 202b is electrically connected to the main voltage dividing resistor 20 to detect a voltage change of the main voltage dividing resistor 20, and the main control module 202a and
  • the LED driving output terminal 100 is electrically connected, and the voltage of the LED driving output terminal 100 is adjusted according to the detection result fed back by the main detecting module 202b;
  • the slave IC 302 includes an electrical connection slave control module 302a and a slave detection module 302b, the slave detector
  • the measuring module 302a is electrically connected to the voltage dividing resistor 30, detects the voltage change from the voltage dividing resistor 30, is electrically connected from the control module 302a and the LED driving output terminal 100, and adjusts the LED driving output according to the detection result fed back from the detecting module 302b. 100 voltage.
  • the minimum divided voltage on the slave IC overvoltage trigger circuit may be set to be greater than the maximum score of the main IC overvoltage trigger circuit. Voltage, in this way, the voltage divider resistor from the IC overvoltage trigger circuit can first reach the voltage from the IC overvoltage protection trigger point.
  • the minimum divided voltage on the slave IC overvoltage trigger circuit is 0.7-lV higher than the maximum divided voltage of the main IC overvoltage trigger circuit.
  • the main IC overvoltage trigger circuit 201 includes at least two main voltage dividing resistors 20 connected in series
  • the slave IC overvoltage trigger circuit 301 also includes at least two slave voltage dividing resistors 30 connected in series, wherein An overvoltage protection trigger point of the main IC is provided between the voltage resistors 20, and an overvoltage protection trigger point from the IC is set between the voltage dividing resistors 20.
  • Adjust the voltage distribution on each resistor to achieve different purposes for the overvoltage trigger point of the master-slave IC.
  • the main voltage dividing resistor includes a first resistor (R1 ') and a second resistor (R2') connected in series with each other, and the first resistor (R1 ') is disposed at an overvoltage protection trigger point and driving of the main IC.
  • the second resistor (R2') is disposed between the overvoltage protection trigger point of the main IC and the ground end, and the detection point of the main detection module 202b is set to the first resistor (R1 ') and the second The resistor (R2,) is connected; the voltage divider resistor includes a third resistor (R3,) and a fourth resistor (R4,), and the third resistor (R3,) is disposed at an overvoltage protection trigger point and a driving output terminal of the IC.
  • the fourth resistor (R4') is disposed between the overvoltage protection trigger point of the IC and the ground, and the detection point of the detecting module 302b is disposed between the third resistor (R3') and the fourth resistor ( Between R4'), the working status of the respective connected LED strings is detected by the main IC and the slave IC, respectively.
  • the ratio of the sum of the resistance values of the fourth resistor (R4') and the third resistor (R3') and the fourth resistor (R4') from the voltage dividing resistor is greater than the second resistor (R2') of the main voltage dividing resistor
  • the ratio of the sum of the resistance values of the first resistor (R1 ') and the second resistor (R2') That is, the following conditions are met:
  • the voltage value of the overvoltage protection trigger point from the IC302 is set lower than the overvoltage protection trigger point of the main IC 202, and the voltage of the fourth resistor (R4') is higher than the second resistance (R2'). Then, the voltage of the fourth resistor (4') first reaches the overvoltage protection trigger point of the IC, and is triggered from the overvoltage protection circuit of the IC.
  • the voltage of the LED driving output terminal is set to 24V, which is obtained by the common control of the inductor and the MOS tube, and the load voltage of each LED string is controlled according to the driving signal of the main IC to adjust the output control MOS tube.
  • the drive signal of the MOS transistor is intelligently separated by a single IC. Control, that is, controlled by the main IC, otherwise it will cause circuit disorder and work abnormally.
  • the slave IC it is necessary to start the output overvoltage protection before the output voltage reaches 90V.
  • 85V can be selected to calculate the ratio of R3' and R4'.
  • the control signal is output from the IC control module 302a to the main IC control.
  • the module 202a, the main control module 202a of the main IC controls the duty ratio of the driving signal output to the MOS tube, the duty ratio is increased, the output voltage is increased, and the output voltage is divided by the voltage dividing resistor Rl '-R4'.
  • the voltage at the LED driver output continues to rise to the main IC202
  • the main IC 202 also triggers its own overvoltage protection function.
  • the voltage from the voltage dividing resistor R4' first reaches the overvoltage protection trigger point of the IC302, so that the IC302 is obtained from the IC302. Triggering its own overvoltage protection function in advance, and eliminating the abnormality of the LED string. Since the negative end of the LED string is connected to the slave ICpin, the test control circuit connected from the IC302 to the negative terminal of the LED string is turned off, and the slave control module 302a is turned off.
  • the following is calculated according to the output voltage.
  • the normal output voltage of the main IC is set to Va-Vb. There is a certain floating range. It is determined that the stable output voltage of the whole circuit is Vout, and the maximum output overvoltage is set to 1.2 Vout.
  • the R1 ' ⁇ R4' resistance value first determine the size of Rl ', R2', and the main IC calculates the ratio of R2V R1 '+R2') to Va/(Va(()) according to Va and the output overvoltage maximum value of 1.2*Vout.
  • the specific resistance of Rl ', R2' can be arbitrarily selected at the level; in order to ensure that the maximum output overvoltage when triggering from the IC is less than the main IC, the slave IC outputs a maximum overvoltage of 1.2 based on Vb and ratio.
  • Vout small voltage, calculate the ratio of R4V (R3'+R4') is larger than Vb/(1.2*Vout), and the specific resistance of Rl ', R2' can be arbitrarily selected at the kO.
  • the ratio of R4V (R3'+R4') is greater than R2V (Rr+R2'), so that at any output voltage, the voltage on R4' must be greater than the voltage on R2', ie the IC will be in the main IC.
  • the output overvoltage protection function is triggered before.
  • the overvoltage protection trigger point / [the maximum output voltage from the IC overvoltage protection is from the IC overvoltage protection trigger point].
  • the main IC overvoltage trigger circuit 201 includes three main voltage dividing resistors 20 connected in series, and the main voltage dividing resistor includes a first resistor (R1) and a second The resistor (R2) and the third resistor (R3), the first resistor (R1) and the second resistor (R2) are disposed between the overvoltage protection trigger point of the main IC and the driving output terminal, and the third resistor (R3) is disposed at The overvoltage protection trigger point of the main IC and the ground terminal, the fourth resistor (R4) and the fifth resistor (R5) are disposed between the overvoltage protection trigger point of the slave IC and the driving output terminal, and the sixth resistor (R6) It is disposed between the overvoltage protection trigger point of the slave IC and the ground terminal, wherein the sixth resistor (R6) and the fourth resistor (R4), the fifth resistor (5), and the sixth resistor (R6) from the voltage dividing resistor The ratio of the sum of the resistance values is
  • the voltage value of the overvoltage protection trigger point from the IC302 is set lower than the overvoltage protection trigger point of the main IC 202, and the voltage of the sixth resistor (R6) is higher than the third resistor (R3), The voltage of the resistor (R6) first reaches the overvoltage protection trigger point of the IC, and is triggered from the overvoltage protection circuit of the IC.
  • the slave IC it is necessary to start the output overvoltage protection before the output voltage reaches 90V. From the IC overvoltage trigger circuit, 85V can be selected to calculate the ratio of R4, R5 and R6.
  • the voltage division principle the main voltage dividing resistor and the voltage value from both ends of the voltage dividing resistor are distributed according to the resistance ratio.
  • the specific resistance values of R4, R5 and R6 can be arbitrarily selected at the level; overall, the ratio of R6/(R4+R5+R6) is greater than R3/(R1+R2+R3), so that it is arbitrary At the output voltage, the voltage on R6 must be greater than the voltage on R3, that is, the slave will trigger the output overvoltage protection function before the main IC.
  • first resistor and the second resistor can be replaced by one resistor.
  • third resistor R3 can also be replaced by multiple resistors, as long as the above calculation ratio is satisfied.
  • the number and arrangement of the voltage divider resistors can be adjusted as needed.
  • the voltage value across the sixth resistor R6 in the voltage dividing resistor is greater than the voltage value across the third resistor R3 in the main voltage dividing resistor, and the voltage across the sixth resistor R6 of the voltage dividing resistor is first reached.
  • the overvoltage protection function of the IC302 is triggered in advance, and the voltage/current detection of the open LED string from the detection module 302b is turned off from the control module 302a, so that the entire circuit is returned. The state of normal work.
  • the main IC 202 When the voltage of the LED driving output terminal 100 continues to rise to the overvoltage protection trigger point of the main IC 202, the main IC 202 also triggers its own overvoltage protection function, and the main control module 202a turns off the main detection module 202b to open the LED string. At the same time, the main control module 202a controls the duty cycle D value of the MOS transistor to decrease, so that the output voltage of the LED drive output terminal 100 is lowered to the voltage at which the LED string operates normally. Among them, set a plurality of main divider resistors and slave divider resistors, and change the voltage across the resistors by fine tuning between R1 and R2 or R4 and R5.
  • the overvoltage protection trigger point inside the master-slave IC ranges from 2.4V to 2.6V, and the overvoltage protection trigger point from the IC is lower than the overvoltage protection trigger point of the main IC, and the main IC has passed
  • the voltage protection trigger point is 2.6V; the overvoltage protection trigger point from the IC is 2.4V.
  • the size of each voltage dividing resistor can be adjusted according to the setting range of the overvoltage protection trigger point to ensure that the protection is triggered before the output voltage rises from the IC to ensure stable operation of the entire circuit.
  • the present invention also provides an overvoltage protection method using the above overvoltage protection circuit, which comprises the following steps: Step 1) In the main IC overvoltage trigger circuit and the slave IC overvoltage trigger circuit, set the overvoltage protection trigger point of the main IC and the slave IC, and the voltage of the overvoltage protection trigger point of the slave IC is lower than that of the main IC Voltage protection trigger point voltage;
  • Step 2 As the output voltage rises, when the voltage from the voltage-receiving resistor is detected from the slave detection module of the IC, it is compared with the overvoltage protection trigger point from the IC:
  • a shutdown detection command is sent from the control module to the open LED string, and the current/voltage detection of the corresponding LED string is controlled to be turned off;
  • Step 3 When the main detection module of the main IC detects that the voltage on the main divider resistor is compared with the overvoltage protection trigger point of the main IC: If the voltage on the main divider resistor reaches the overvoltage protection trigger point of the main IC, the main The control module sends a shutdown command to the LED string that has an open circuit, controls the corresponding LED string to be turned off, and drives the output voltage to decrease;
  • Step 4) The main control module adjusts the voltage adjustment range of the LED drive output according to the feedback value of the main detection module. Step 41) When the main control module needs to increase the output voltage according to the feedback value of the main detection module, the main control module sends a boost control signal to the MOS tube, and the driving MOS tube increases the duty ratio to drive the LED driving output end. Voltage increase range;
  • Step 42) If it is necessary to reduce the output voltage, the main control module sends a buck control signal to the MOS transistor, and the driving MOS transistor reduces the duty ratio to drive the voltage drop of the LED driving output terminal.
  • the overvoltage protection trigger point is respectively set in the main IC 202 and the slave IC 302. As the output voltage rises, in the slave IC 302, when the voltage from the voltage dividing resistor 30 is detected from the detecting module 302b, the overvoltage from the IC 302 is reached. When the trigger point is protected, a shutdown detection command is sent from the control module 302a to the LED string 402 that has an open circuit, and the current/voltage detection of the corresponding LED string 402 is turned off.
  • the main control module 202a sends a shutdown command to the LED string 401 in which the open circuit is opened, controls the corresponding LED string 401 to be turned off, and drives the output voltage to decrease.
  • the main control module 202a according to the feedback value of the main detection module 202b, when the output voltage needs to be increased, the main control module 202a sends a boost control signal to the MOS transistor, and the MOS transistor is driven to increase the duty ratio.
  • the voltage driving output of the LED driving output terminal is increased; when the output voltage needs to be lowered, the main pumping control module 202a sends a buck control signal to the MOS transistor, and the driving MOS transistor reduces the duty ratio to drive the voltage drop of the LED driving output terminal. .
  • the main detection module 202b is electrically connected to each LED string, and each LED string is connected in series with the current limiting resistor 403, and the current limiting circuit 403 is used to limit the current of the LED string shunt to avoid excessive current burning. LED string.
  • the main detection module 202b detects that the current limiting resistor 403 voltage/current value in a certain LED string circuit is higher than the set value, it is fed back to the main control module 202a, and is sent to the LED string 401 by the main control module 202a.
  • the slave detection module 202b is electrically connected to each LED string 402.
  • the LED strings 402 are respectively connected in series with the current limiting resistor 403.
  • the detection module 302b measures the limit of a certain LED string 402 circuit.
  • the feedback to the slave control module 302a is sent from the control module 302a to the LED string 402 to send a shutdown detection command, and the control slave detection module 302b turns off the corresponding LED.
  • the LED string can be marked and sent to the main control module 202a and the slave.
  • the control module 302a is configured to know which group of LED strings is open circuited, and sends corresponding commands to the MOS tube for buck-boost or on-off for negative feedback control.
  • the main IC overvoltage trigger circuit 201 and the two sets of LED strings are connected in parallel with each other, and the slave overvoltage trigger circuit 301 is also connected in parallel with the two sets of LED strings. It can be understood that the number of the LED strings is Without being limited to this, it can be determined according to the number of LED strings required for the LCD TV.
  • the present invention also provides a panel driving circuit with the overvoltage protection circuit, comprising an LED string with a main IC and a slave IC, and a voltage for driving the output of the LED string with the main IC and the slave IC Adjusted overvoltage protection circuit.
  • an overvoltage trigger circuit is separately provided in the main IC and the slave IC, and is separately controlled.
  • the resistance distribution of the overvoltage resistor makes the overvoltage protection trigger point setting from the IC lower than the overvoltage protection trigger point of the main IC.
  • the voltage of the LED driver output terminal controlled by the acceptor IC reaches the highest value, the voltage rises to
  • the overvoltage protection trigger point of the IC is set, the IC will trigger its own overvoltage protection function in advance, so that it can be turned off by the negative feedback control from the detection module and the slave control module.
  • Control stop the current/voltage detection, so that the whole circuit returns to the normal working state, to avoid the interference of the voltage instability of the local LED string circuit on the entire liquid crystal display. If the voltage of the LED driver output continues to rise to the overvoltage protection trigger point set by the main IC, the main IC also triggers its own overvoltage protection function, which is controlled by the negative feedback of the main detection module and the main control module.
  • the open-circuit LED string interrupt detection occurs in parallel, and at the same time, the buck command MOS transistor is sent to drive the voltage drop of the LED drive output terminal to lower the output voltage to the LED string to ensure the stability of the entire LED string circuit voltage.
  • the overvoltage protection function of the main IC and the slave IC are triggered in the same abnormal situation, and the main IC and the slave IC can respectively detect the working status of the LED string connected thereto, and the LED string corresponding to the open circuit will appear.
  • the internal detection line of the IC is disconnected, and the remaining LED strings form a new line, continue to work normally, the output voltage is reduced and restored to a normal value, and the high voltage state is avoided, making the entire circuit unstable.
  • the overvoltage protection circuit of the present invention changes the selection ratio of the main IC and the slave voltage dividing resistor, so that when an abnormality occurs, the main IC controls the output voltage to rise, and the slave IC triggers the overvoltage protection function before the main IC.

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Abstract

一种过压保护电路、保护方法及面板驱动电路，其中，过压保护电路用于对带主IC（202）和从IC（302）的LED串（401，402）的驱动输出端电压进行调节，其包括主IC过压触发电路（201）和从IC过压触发电路（301），其中，主IC过压触发电路（201）分别与主IC（202）及若干组LED串（401）电连接，从IC过压触发电路（301）分别与从IC（302）及若干组LED串（402）电连接，在主IC和从IC模块中分别设定过压保护触发点，从IC的过压保护触发点的电压低于主IC的过压保护触发点的电压。

Description

一种过压保护电路、 过压保护方法及面板驱动电路
技术领域
本发明涉及一种过压保护电路、保护方法及面板驱动电路， 尤其是指一种通过主从 IC的 过压触发电路分别对 LED串起过压保护的电路和保护方法， 以及采用所述过压保护电路的面 板驱动电路。
背景技术
单颗 LED恒流驱动 IC的通道数 （可驱动的 LED串数）有限， 当大尺寸液晶电视需要更 多的 LED串来提供高亮度的背光照明时， 需要使用到多颗 IC连接起来使用， 其中一颗 IC要 给 MOS管提供驱动信号， 这样整个电路才能正常工作， 这颗 IC称为主 IC， 其它的 IC只需 要提供连接 LED串的调光 pin脚即可， 这些 IC称为从 IC。传统的多颗 IC主从模式连接时的 电路如图 1所示， 每颗 IC的输出过压保护点都需要分压电阻来设置， 如果每颗 IC的输出过 压保护点都设置为一样， 可能因电阻精度或者 IC个体差异， 导致实际工作时触发每颗 IC过 压保护的电压值会存在差异， 可能会出现 IC无法触发保护功能的情况。
多颗 IC主从模式连接时， 输出电压大小只由主 IC输出的驱动信号决定， 如果出现主 IC 的过压保护触发电压值小于从 IC的触发电压值情况时， 当与从 IC连接的 LED串出现开路， 输出电压受主 IC控制而上升， 达到主 IC的过压保护触发点后停止上升， 这时候， 主 IC过压 保护功能触发， 开始侦测与主 IC连接的各 LED串情况； 而从 IC因过压保护触发电压值大， 并不能触发其自身的过压保护功能， 导致从 IC不能将出现开路的 LED串关闭， 主 IC控制输 出电压一直保持在高电压状态， 整个线路不稳定。
因此， 有必要提供可对可通过主从 IC分别对 LED串的电压状况进行单独控制的过压保 护电路。
发明内容
基于现有技术的不足， 本发明的主要目的在于提供一种可通过主从 IC分别对 LED串的 电压进行单独控制的过压保护电路， 使得出现异常状况时， 主从 IC的输出电压保护功能都能 发挥作用。
本发明的另一目的在于提供一种带所述过压保护电路的过压保护方法。
本发明的另一目的在于提供一种带所述过压保护电路的面板驱动电路。
本发明提供了一种过压保护电路， 用于对带主 IC和从 IC的 LED串的驱动输出端电压进 行调节， 其包括主 IC过压触发电路和从 IC过压触发电路， 其中： 所述主 IC过压触发电路分 别与主 IC及若干组 LED串电连接，所述从 IC过压触发电路分别与从 IC及若干组 LED串电 连接， 在主 IC和从 IC中分别设定过压保护触发点， 所述从 IC的过压保护触发点的电压低于 主 IC的过压保护触发点的电压。
优选地， 所述从 IC过压触发电路上的最小分压大于主 IC过压触发电路的最大分压。 所 述从 IC过压触发电路上的最小分压比主 IC过压触发电路的最大分压高 0.7-1 V。所述主 IC过 压触发电路包括至少两个相互串联的主分压电阻，所述从 IC过压触发电路亦包括至少两个相 互串联的从分压电阻， 其中， 在主分压电阻之间设置主 IC的过压保护触发点， 在从分压电阻 之间设置从 IC的过压保护触发点。
优选地， 所述主分压电阻包括第一电阻和第二电阻， 第一电阻设置于主 IC的过压保护触 发点与驱动输出端之间， 第二电阻设置于主 IC的过压保护触发点与接地端之间， 从分压电阻 包括第三电阻和第四电阻， 第三电阻设置于从 IC的过压保护触发点与驱动输出端之间， 第四 电阻设置于从 IC的过压保护触发点与接地端之间， 其中， 从分压电阻中第四电阻与第三电阻 与第四电阻的电阻值之和的比值大于主分压电阻中第二电阻与第一电阻与第二电阻的电阻值 之和的比值。
优选地， 所述主分压电阻包括第一电阻、 第二电阻和第三电阻， 第一电阻和第二电阻设 置于主 IC的过压保护触发点与驱动输出端之间， 第三电阻设置于主 IC的过压保护触发点与 接地端之间， 第四电阻和第五电阻设置于从 IC的过压保护触发点与驱动输出端之间， 第六电 阻设置于从 IC的过压保护触发点与接地端之间，其中，从分压电阻中的第六电阻与第四电阻、 第五电阻和第六电阻的电阻值之和的比值大于主分压电阻中的第三电阻与第一电阻、 第二电 阻和第三电阻的电阻值之和的比值。 其中， 主分压电阻中的第三电阻的电阻值可与第六电阻 的电阻值相等。
优选地， 所述主 IC包括电连接的主控制模块和主侦测模块， 所述主侦测模块与主分压电 阻电连接， 检测主分压电阻的电压变化， 主控制模块与 LED串的驱动输出端电连接， 根据主 侦测模块的检测结果调整驱动输出端的电压；所述从 IC包括电连接的从控制模块和从侦测模 块， 所述从侦测模块与从分压电阻电连接， 检测从分压电阻的电压变化， 从控制模块与驱动 输出端电连接， 根据从侦测模块的检测结果调整驱动输出端电压， 随着输出电压的上升， 在 从 IC中， 当从侦测模块检测到从分压电阻上的电压达到从 IC的过压保护触发点时， 从控制 模块向出现开路的 LED串发送关闭侦测指令， 中断对其的电压 /电流侦测； 在主 IC中， 当主 侦测模块检测到主分压电阻上的电压达到主 IC的过压保护触发点时，主控制模块向出现开路 的 LED串发送关闭侦测指令， 中断对其的电压 /电流侦测， 并驱动 LED串的驱动输出端的输 出电压降低。
优选地， 所述主侦测模块与各 LED串分别电连接， 各 LED串分别与限流电阻串联， 当 主侦测模块测得某一 LED串电路中的限流电阻电压值高于设定值时， 反馈至主控制模块， 由 主控制模块向所述 LED串发送关闭侦测指令，控制关闭对相应的 LED串的侦测，并控制 LED 串驱动输出端的输出电压降低； 所述从侦测模块与各 LED串分别电连接， 所述各 LED串分 别与限流电阻串联， 当从侦测模块测得某一 LED串电路中的限流电阻高于设定值时， 反馈至 从控制模块， 由从控制模块向所述 LED串发送关闭侦测指令， 控制关闭对相应的 LED串的 侦测； 所述主 IC和从 IC分别对各 LED串的通断进行负反馈控制。
本发明还提供了一种采用上述过压保护电路的过压保护方法， 其包括以下步骤： 步骤 1 )在主 IC过压触发电路和从 IC过压触发电路中， 设置主 IC和从 IC的过压保护触 发点， 所述从 IC的过压保护触发点的电压低于主 IC的过压保护触发点的电压；
步骤 2)随着输出电压的上升， 当从 IC的从侦测模块检测到从分压电阻上的电压与从 IC 的过压保护触发点比较：
若从分压电阻上的电压达到从 IC 的过压保护触发点时， 从控制模块向出现开路的 LED 串发送关闭侦测指令， 控制关闭对相应的 LED串的电流 /电压侦测；
步骤 3 )当主 IC的主侦测模块检测到主分压电阻上的电压与主 IC的过压保护触发点比较: 若主分压电阻上的电压达到主 IC 的过压保护触发点时， 主控制模块向出现开路的 LED 串发送关闭指令， 控制相应的 LED串关闭， 并驱动输出电压降低；
步骤 4) 主控制模块根据主侦测模块的反馈值， 调整 LED驱动输出端的电压调整幅度。 步骤 41 ) 主控制模块根据主侦测模块的反馈值， 需要提高输出电压时， 则由主控制模块 发送升压控制信号至 MOS管， 驱动 MOS管提高占空比， 使其驱动 LED驱动输出端的电压 上升幅度；
步骤 42) 若需要降低输出电压时， 则由主控制模块发送降压控制信号至 MOS管， 驱动 MOS 管降低占空比， 使其驱动 LED驱动输出端的电压下降幅度。
本发明还提供了面板驱动电路， 包括带主 IC和从 IC的 LED串、 及用于对带主 IC和从 IC的 LED串的驱动输出端电压进行调节的上述过压保护电路。
与现有技术相比， 本发明一种过压保护电路、 保护方法及其面板驱动电路， 其中， 所述 过压保护电路在主 IC和从 IC分别设置过压触发电路， 通过改变主 IC和从 IC与过压触发电 路的连接方式， 以及主从 IC的分压电阻的选取比例， 并将从 IC的过压保护触发点设置比主 IC的低， 使得当出现异常状况时， 随着输出电压的上升， 从 IC比主 IC先触发输出过压保护 功能， 以对 LED串的工作状态进行实时反映。 若达到主 IC的过压保护触发点时， 则由其控 制 LED驱动输出端的电压大小， 致使整个电路处于稳压状态。
附图说明 图 1为现有过压保护电路的电路图；
图 2为本发明一种过压保护电路的电路框图；
图 3为本发明实施例一过压保护电路的电路图；
图 4为本发明实施例二过压保护电路的电路图。
具体实施方式
参照图 2所示， 为了对大液晶电视中多组 LED串的驱动输出电压进行控制调整， 以解决 多组 LED串与主 IC及从 IC连接时， 出现的输出电压过压的保护问题。本发明提供了一种过 压保护电路， 用于对带主 IC202和从 IC302的 LED串 401、 402的驱动输出端 100电压进行 调节， 其包括主 IC过压触发电路 201和从 IC过压触发电路 202， 其中： 所述主 IC过压触发 电路 201分别与主 IC202及若干组 LED串 401电连接， 所述从 IC过压触发电路 201分别与 从 IC302及若干组 LED串 402电连接， 在主 IC202和从 IC302中分别设定过压保护触发点， 所述从 IC302的过压保护触发点的电压低于主 IC202的过压保护触发点的电压。 主 IC202根 据主 IC过压触发电路 201反馈的电压变化值来控制与之连接的 LED串 401的通断， 并调整 输出电压的大小； 所述从 IC过压触发电路 301与从 IC302连接， 并与若干组 LED串 402连 接， 从 IC302根据从 IC过压触发电路 301反馈的电压变化来控制与之连接的 LED串 402的 通断， 以保障 LED驱动输出端 100可正常供电， 避免输出电压长时间保持高压状态， 使得整 个电路不稳定。
所述主 IC202包括电连接的主控制模块 202a和主侦测模块 202b， 所述主侦测模块 202b 与主分压电阻 20电连接， 检测主分压电阻 20的电压变化， 主控制模块 202a与 LED驱动输 出端 100电连接， 根据主侦测模块 202b反馈的检测结果调整 LED驱动输出端 100的电压； 所述从 IC302包括电连接的从控制模块 302a和从侦测模块 302b， 所述从侦测模块 302a与从 分压电阻 30电连接， 检测从分压电阻 30的电压变化， 从控制模块 302a与 LED驱动输出端 100电连接， 根据从侦测模块 302b反馈的检测结果调整 LED驱动输出端 100的电压。
为了使得从 IC302的过压保护触发点的电压低于主 IC202的过压保护触发点的电压， 可 以设置所述从 IC过压触发电路上的最小分压大于主 IC过压触发电路的最大分压， 这样， 从 IC过压触发电路上的分压电阻可先达到从 IC的过压保护触发点的电压。 优选地， 所述从 IC 过压触发电路上的最小分压比主 IC过压触发电路的最大分压高 0.7-lV。
参照图 2-3所示，以下对主 IC过压触发电路 201和从 IC过压触发电路 301进行详细说明。 所述主 IC过压触发电路 201包括至少两个相互串联的主分压电阻 20， 所述从 IC过压触发电 路 301亦包括至少两个相互串联的从分压电阻 30， 其中， 在主分压电阻 20之间设置主 IC的 过压保护触发点， 在从分压电阻 20之间设置从 IC的过压保护触发点。 通过阻值的分配， 来 调整各电阻上的电压分配， 以实现主从 IC的过压触发点不同的目的。
本实施例中， 所述主分压电阻包括相互串联的第一电阻 （R1 ' ) 和第二电阻 （R2' )， 第一 电阻（R1 ' )设置于主 IC的过压保护触发点与驱动输出端之间， 第二电阻（R2' )设置于主 IC 的过压保护触发点与接地端之间， 主侦测模块 202b的侦测点设置于对第一电阻 （R1 ' ) 和第 二电阻 （R2，） 之间； 从分压电阻包括第三电阻 （R3，） 和第四电阻 （R4，）， 第三电阻 （R3，） 设置于从 IC的过压保护触发点与驱动输出端之间， 第四电阻（R4' )设置于从 IC的过压保护 触发点与接地端之间，从侦测模块 302b的侦测点设置于对第三电阻（R3' )和第四电阻（R4' ) 之间， 通过主 IC和从 IC分别侦测各自连接的 LED串的工作状况。 其中， 从分压电阻中第四 电阻（R4' )与第三电阻 （R3' )与第四电阻（R4' ) 的电阻值之和的比值大于主分压电阻中第 二电阻（R2' )与第一电阻（R1 ' )与第二电阻（R2' )的电阻值之和的比值。 即满足以下条件:
R2' R4'
>
。根据分压原理， 使得从 IC302的过压保护触发点的电压值设置为比 主 IC202的过压保护触发点低， 第四电阻（R4' ) 的电压升高比第二电阻（R2' )， 则第四电阻 ( 4' ) 的电压先达到从 IC的过压保护触发点， 从 IC的过压保护电路先触发。
参照图 3所示， 在实施例一中， 设定 LED驱动输出端的电压为 24V， 通过电感和 MOS 管共同控制获得，各 LED串的负载电压大小根据主 IC调整输出控制 MOS管的驱动信号占空 比大小来调整， 输出电压 VQ=Vin(l-D)， 其中， D为 MOS管驱动信号的占空比大小， 在多颗 IC主从模式下， MOS管的驱动信号智能由单独一颗 IC控制， 即由主 IC控制， 否则会产生 电路紊乱， 工作异常。
设定主 IC内部的过压保护触发点范围为 2.4V~2.6V，则需要将 LED驱动输出端的输出电 压最高值控制在 90V (考虑到电路中元器件的耐压值大小， 所以输出电压不能太大）， 主 IC 过压触发电路 201 就需要以 2.4V 触发电压来选取主分压电阻 R1 '和 R2'， 即 R2'/ l =2.4/(90-2.4), 具体阻值可以任意选取， 只要满足此比例即可， 根据分压原理， 主分压 电阻 R1 '禾 Π R2'两端的电压值按阻值比例分配。 对于从 IC， 需要在输出电压达到 90V之前启 动输出过压保护， 从 IC过压触发电路可以选取 85V来计算 R3'和 R4'的比例， 为了保证从 IC 先触发保护模式， 从 IC就要以 2.6V触发电压来计算， 即 R47 R3'=2.6/(85-2.6)， 具体阻值可 以任意选取， 只要满足比例即可。
当其中与从侦测模块相连的某一 LED串出现异常情况 （开路或某颗 LED损坏不亮）， 从 侦测模块 302b检测到异常状况后，从 IC控制模块 302a输出控制信号至主 IC控制模块 202a， 主 IC的主控制模块 202a控制输出给 MOS管的驱动信号占空比大小， 占空比增大，输出电压 升高，输出电压经过分压电阻 Rl '-R4'分压后，当 LED驱动输出端的电压持续上升至主 IC202 的过压保护触发点时， 则主 IC202亦触发自身的过压保护功能， 控制过程如前所述， 从分压 电阻 R4'两端的电压先达到从 IC302的过压保护触发点， 使得从 IC302提前触发自身的过压 保护功能， 将出现异常情况的 LED串排除， 由于 LED串负端与从 ICpin脚连接， 将从 IC302 与 LED串负端连接的测试控制电路关断，通过从控制模块 302a关闭从侦测模块 302b对出现 开路的 LED串的电压 /电流侦测， 即不再侦测出现异常状况的 LED串的电压 /电流， 这时， 剩 余其他的 LED串仍保持正常工作， 主 IC将控制输出给 MOS管的驱动信号的占空比 D减小， 输出电压再降低至 LED串正常工作时的电压值。
以下根据输出电压来计算， 设定主 IC的正常输出电压为 Va-Vb， 存在一定的浮动范围， 确定整个电路稳定的输出电压为 Vout， 设定输出过压最大值为 1.2 Vout。设计 R1 '~R4'电阻值 时，先确定 Rl '、 R2'的大小，主 IC根据 Va和输出过压最大值 1.2*Vout，计算出 R2V R1 '+R2') 的比例大小为 Va/(1.2*Vout)， Rl '、 R2'的具体阻值可以在 级别上任意选取； 为了保证从 IC触发时的输出过压最大值小于主 IC， 则从 IC根据 Vb和比输出过压最大值 1.2*Vout偏小 的电压， 计算出 R4V(R3'+R4')的比例大小要大于 Vb/(1.2*Vout)， Rl '、 R2'的具体阻值可以在 kO.级别上任意选取； 整体而言， R4V(R3'+R4')的比例要大于 R2V(Rr+R2')， 这样在任意的 输出电压时刻， R4'上的电压一定大于 R2'上的电压， 即从 IC会在主 IC之前触发输出过压保 护功能。
本发明中，主分压电阻满足以下条件：第三电阻（R3 ) /【第一电阻（Rl ) +第二电阻（R2)】 =主 IC的过压保护触发点 /【主 IC过压保护时的最大输出电压一主 IC的过压保护触发点】； 所述从分压电阻满足以下条件： 第六电阻（R6) I【第四电阻（R4) +第五电阻（R5 )】 =从1。 的过压保护触发点 /【从 IC过压保护时的最大输出电压一从 IC的过压保护触发点】。
参照图 4所示， 在优选实施例二中， 所述主 IC过压触发电路 201包括三个相互串联的主 分压电阻 20， 所述主分压电阻包括第一电阻 （Rl )、 第二电阻 （R2) 和第三电阻 （R3 )， 第 一电阻 （R1 ) 和第二电阻 （R2) 设置于主 IC 的过压保护触发点与驱动输出端之间， 第三电 阻 （R3 ) 设置于主 IC的过压保护触发点与接地端之间， 第四电阻 （R4) 和第五电阻 （R5 ) 设置于从 IC的过压保护触发点与驱动输出端之间， 第六电阻 （R6) 设置于从 IC的过压保护 触发点与接地端之间， 其中， 从分压电阻中的第六电阻 （R6) 与第四电阻 （R4)、 第五电阻 ( 5 )和第六电阻（R6) 的电阻值之和的比值大于主分压电阻中的第三电阻（R3 )与第一电 阻 （Rl )、 第二电阻 （R2 ) 和第三电阻 （R3 ) 的电阻值之和的比值。 即满足以下条件：
3 6
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R1+R2+R3 R4+R5+R6 。 根据分压原理， 使得从 IC302的过压保护触发点的电压值设置 为比主 IC202 的过压保护触发点低， 第六电阻 （R6) 的电压升高比第三电阻 （R3 )， 、 电阻 （R6) 的电压先达到从 IC的过压保护触发点， 从 IC的过压保护电路先触发。
同样地， 设定主 IC内部的过压保护触发点范围为 2.4V~2.6V， 则需要将 LED驱动输出端 的输出电压最高值控制在 90V， 主 IC过压触发电路中的主分压电阻 Rl、 R2和 R3， 需满足 3/ ( 1+ 2) =2.4/(90-2.4), 具体阻值可以任意选取， 只要满足此比例即可。 对于从 IC， 需 要在输出电压达到 90V之前启动输出过压保护，从 IC过压触发电路可以选取 85V来计算 R4、 R5和 R6的比例， 为了保证从 IC先触发保护模式， 从 IC就要以 2.6V触发电压来计算， 即 6/ ( 4+ 5 ) =2.6/(85-2.6), 具体阻值可以任意选取， 只要满足比例即可。 根据分压原理， 主分压电阻和从分压电阻两端的电压值按阻值比例分配。
根据输出电压计算电阻分配， 计算出 R3/(R1+R2+R3)的比例大小为 Va/(1.2*Vout)， R R2和 R3的具体阻值可以在 级别上任意选取； 为了保证从 IC触发时的输出过压最大值小 于主 IC， 则从 IC根据 Vb和比输出过压最大值 1.2*Vout偏小的电压， R6/(R4+R5+R6)的比例 大小要大于 Vb/(1.2*Vout)， R4、 R5和 R6的具体阻值可以在 级别上任意选取； 整体而言， R6/(R4+R5+R6)的比例要大于 R3/(R1+R2+R3)， 这样在任意的输出电压时刻， R6上的电压一 定大于 R3上的电压， 即从 IC会在主 IC之前触发输出过压保护功能。
其中， 第一电阻和第二电阻 （R1+R2) 可使用一颗电阻代替， 相同地， 第三电阻 R3也可 以使用多颗电阻代替， 只要满足以上的计算比例即可。 分压电阻的个数和排列方式可根据需 要调整。
经计算得出，所述从分压电阻中的第六电阻 R6两端的电压值大于主分压电阻中的第三电 阻 R3两端的电压值，从分压电阻第六电阻 R6两端的电压先达到从 IC302的过压保护触发点， 使得从 IC302提前触发自身的过压保护功能， 通过从控制模块 302a关闭从侦测模块 302b对 出现开路的 LED串的电压 /电流侦测， 使得整个电路回到正常工作时的状态。 当 LED驱动输 出端 100的电压持续上升至主 IC202的过压保护触发点时， 则主 IC202亦触发自身的过压保 护功能， 通过主控制模块 202a关闭主侦测模块 202b对出现开路的 LED串的电压 /电流侦测， 同时， 主控制模块 202a控制 MOS管的占空比 D值下降， 使得 LED驱动输出端 100的输出 电压降低至 LED串正常工作时的电压。 其中， 设置多个主分压电阻和从分压电阻， 通过 R1 和 R2或 R4和 R5之间的微调来改变各电阻两端的电压。
在本发明中， 所述主从 IC内部的过压保护触发点范围为 2.4V— 2.6V， 从 IC的过压保护 触发点低于主 IC的过压保护触发点， 所述主 IC的过压保护触发点为 2.6V; 从 IC的过压保 护触发点为 2.4V。 可根据过压保护触发点的设置范围来调整所设置的各分压电阻的大小， 以 保证在输出电压上升时， 从 IC比主 IC先触发保护， 确保整个电路的稳定工作。
本发明还提供了一种采用上述过压保护电路的过压保护方法， 其包括以下步骤： 步骤 1 )在主 IC过压触发电路和从 IC过压触发电路中， 设置主 IC和从 IC的过压保护触 发点， 所述从 IC的过压保护触发点的电压低于主 IC的过压保护触发点的电压；
步骤 2)随着输出电压的上升， 当从 IC的从侦测模块检测到从分压电阻上的电压与从 IC 的过压保护触发点比较：
若从分压电阻上的电压达到从 IC 的过压保护触发点时， 从控制模块向出现开路的 LED 串发送关闭侦测指令， 控制关闭对相应的 LED串的电流 /电压侦测；
步骤 3 )当主 IC的主侦测模块检测到主分压电阻上的电压与主 IC的过压保护触发点比较: 若主分压电阻上的电压达到主 IC 的过压保护触发点时， 主控制模块向出现开路的 LED 串发送关闭指令， 控制相应的 LED串关闭， 并驱动输出电压降低；
步骤 4) 主控制模块根据主侦测模块的反馈值， 调整 LED驱动输出端的电压调整幅度。 步骤 41 ) 主控制模块根据主侦测模块的反馈值， 需要提高输出电压时， 则由主控制模块 发送升压控制信号至 MOS管， 驱动 MOS管提高占空比， 使其驱动 LED驱动输出端的电压 上升幅度；
步骤 42) 若需要降低输出电压时， 则由主控制模块发送降压控制信号至 MOS管， 驱动 MOS 管降低占空比， 使其驱动 LED驱动输出端的电压下降幅度。
参照图 2-图 4所示， 以下进一步说明如何控制 LED串的关断以及输出电压的调整。在主 IC202和从 IC302中分别设定过压保护触发点， 随着输出电压的上升， 在从 IC302中， 当从 侦测模块 302b检测到从分压电阻 30上的电压达到从 IC302的过压保护触发点时， 从控制模 块 302a向出现开路的 LED串 402发送关闭侦测指令， 控制关闭对相应的 LED串 402的电流 /电压侦测； 在主 IC202中， 当主侦测模块 202b检测到主分压电阻 20上的电压达到主 IC202 的过压保护触发点时， 主控制模块 202a向出现开路的 LED串 401发送关闭指令， 控制相应 的 LED串 401关闭， 并驱动输出电压降低。 在本发明中， 主控制模块 202a根据主侦测模块 202b的反馈值，当需要提高输出电压时，则由主控制模块 202a发送升压控制信号至 MOS管， 驱动 MOS管提高占空比， 使其驱动 LED驱动输出端的电压上升幅度； 当需要降低输出电压 时， 贝抽主控制模块 202a发送降压控制信号至 MOS管， 驱动 MOS 管降低占空比， 使其驱 动 LED驱动输出端的电压下降幅度。
所述主侦测模块 202b与各 LED串分别电连接， 各 LED串分别与限流电阻 403串联， 通 过限流电阻 403对 LED串分路的电流进行限流控制， 以避免过大电流烧损 LED串。 当主侦 测模块 202b测得某一 LED串电路中的限流电阻 403电压值 /电流值高于设定值时， 反馈至主 控制模块 202a， 由主控制模块 202a向所述 LED串 401发送关闭侦测指令， 控制主侦测模块 202b关闭对相应的 LED串 401的电流 /电压侦测，并驱动 LED驱动输出端 100的输出电压降 低； 所述从侦测模块 202b与各 LED串 402分别电连接， 所述各 LED串 402分别与限流电阻 403串联， 当从侦测模块测 302b测得某一 LED串 402电路中的限流电阻 403电压值 /电流值 高于设定值时， 反馈至从控制模块 302a， 由从控制模块 302a向所述 LED串 402发送关闭侦 测指令， 控制从侦测模块 302b关闭对相应的 LED串 402的电流 /电压侦测。 根据主侦测模块 202b和从侦测模块 302b所反馈的某一 LED串的电压值或电流值高于设定值，可对所述 LED 串进行标示， 并分别发送至主控制模块 202a和从控制模块 302a， 使其获知哪组 LED串发生 开路， 并发相应指令至 MOS 管对其进行升降压或通断进行负反馈控制。 在本实施例中， 所 述主 IC过压触发电路 201与两组 LED串相互并联， 所述从过压触发电路 301亦与两组 LED 串相互并联， 可以理解， 所述 LED串的个数不受此限， 可根据液晶电视所需的 LED串的个 数来确定。
本发明还提供了一种带所述过压保护电路的面板驱动电路，其包括带主 IC和从 IC的 LED 串、 以及用于对带主 IC和从 IC的 LED串的驱动输出端电压进行调节的过压保护电路。
本发明的过压保护电路， 在主 IC和从 IC分别设置过压触发电路， 并进行单独控制。 过 分压电阻的阻值分配， 使得从 IC的过压保护触发点设置比主 IC的过压保护触发点低， 在受 主 IC控制的 LED驱动输出端电压达到最高值时，则电压上升至从 IC设置的过压保护触发点 时， 从 IC提前触发自身的过压保护功能， 使其通过从侦测模块和从控制模块的负反馈控制， 对与之相并联出现开路的 LED 串关闭侦测控制， 停止对其的电流 /电压侦测， 以使整个电路 又回到正常工作的状态， 以避免局部 LED串电路的电压不稳定对整个液晶显示造成的干扰。 若当 LED驱动输出端的电压持续上升至主 IC设置的过压保护触发点时，则主 IC亦触发自身 的过压保护功能，通过主侦测模块和主控制模块的负反馈控制，对与之相并联出现开路的 LED 串中断侦测， 同时， 发送降压指令 MOS管， 使其驱动 LED驱动输出端的电压下降， 使其降 低向 LED串的输出电压， 以保证整个 LED串电路电压的稳定。 这样， 主 IC和从 IC的过压 保护功能在同一异常情况下均被触发到，主 IC和从 IC可分别对与其相连的 LED串的工作状 况进行实时侦测， 将出现开路的 LED串对应的 IC内部侦测线路断开， 而剩下的 LED串组成 新的线路， 继续正常工作， 输出电压降低并恢复至正常值， 避免处于高压状态， 使得整个电 路不稳定。 本发明的过压保护电路改变了主 IC和从 IC分压电阻的选取比例， 使得当出现异 常时， 主 IC控制输出电压上升的过程中， 从 IC比主 IC先触发过压保护功能。

Claims

权 利 要 求 书
、 一种过压保护电路， 用于对带主 IC和从 IC的 LED串的驱动输出端电压进行调节， 其包括 主 IC过压触发电路和从 IC过压触发电路， 其中： 所述主 IC过压触发电路分别与主 IC及若 干组 LED串电连接， 所述从 IC过压触发电路分别与从 IC及若干组 LED串电连接， 所述主 IC过压触发电路包括至少两个相互串联的主分压电阻， 所述从 IC过压触发电路亦包括至少 两个相互串联的从分压电阻， 其中， 在主分压电阻之间设置主 IC 的过压保护触发点， 在从 分压电阻之间设置从 IC的过压保护触发点， 所述从 IC的过压保护触发点的电压低于主 IC 的过压保护触发点的电压。
、 根据权利要求 1所述的过压保护电路， 其中： 所述从 IC过压触发电路上的最小分压大于主 IC过压触发电路的最大分压。
、 根据权利要求 2所述的过压保护电路， 其中： 所述从 IC过压触发电路上的最小分压比主 IC 过压触发电路的最大分压高 0.7-1 V。
、 根据权利要求 2所述的过压保护电路， 其中： 所述主分压电阻包括第一电阻和第二电阻， 第 一电阻设置于主 IC的过压保护触发点与驱动输出端之间， 第二电阻设置于主 IC的过压保护 触发点与接地端之间， 从分压电阻包括第三电阻和第四电阻， 第三电阻设置于从 IC 的过压 保护触发点与驱动输出端之间， 第四电阻设置于从 IC 的过压保护触发点与接地端之间， 其 中， 从分压电阻中第四电阻与第三电阻与第四电阻的电阻值之和的比值大于主分压电阻中第 二电阻与第一电阻与第二电阻的电阻值之和的比值。
、 根据权利要求 2所述的过压保护电路， 其中： 所述主分压电阻包括第一电阻、第二电阻和第 三电阻， 第一电阻和第二电阻设置于主 IC 的过压保护触发点与驱动输出端之间， 第三电阻 设置于主 IC的过压保护触发点与接地端之间， 第四电阻和第五电阻设置于从 IC的过压保护 触发点与驱动输出端之间， 第六电阻设置于从 IC 的过压保护触发点与接地端之间， 其中， 从分压电阻中的第六电阻与第四电阻、第五电阻和第六电阻的电阻值之和的比值大于主分压 电阻中的第三电阻与第一电阻、 第二电阻和第三电阻的电阻值之和的比值。
、 根据权利要求 5所述的过压保护电路，其中： 主分压电阻中的第三电阻的电阻值与第六电阻 的电阻值相等。
、 根据权利要求 1所述的过压保护电路， 其中： 所述主 IC包括电连接的主控制模块和主侦测 模块， 所述主侦测模块与主分压电阻电连接， 检测主分压电阻的电压变化， 主控制模块与 LED 串的驱动输出端电连接， 根据主侦测模块的检测结果调整驱动输出端的电压； 在主 IC 中， 当主侦测模块检测到主分压电阻上的电压达到主 IC 的过压保护触发点时， 主控制模块 向出现开路的 LED串发送关闭侦测指令， 中断对其的电压 /电流侦测， 并驱动 LED串的驱动 输出端的输出电压降低。
、 根据权利要求 7所述的过压保护电路， 其中： 所述从 IC包括电连接的从控制模块和从侦测 模块， 所述从侦测模块与从分压电阻电连接， 检测从分压电阻的电压变化， 从控制模块与驱 动输出端电连接， 根据从侦测模块的检测结果调整驱动输出端电压， 随着输出电压的上升， 在从 IC中， 当从侦测模块检测到从分压电阻上的电压达到从 IC的过压保护触发点时， 从控 制模块向出现开路的 LED串发送关闭侦测指令， 中断对其的电压 /电流侦测。
、 根据权利要求 1所述的过压保护电路， 其中： 所述主侦测模块与各 LED串分别电连接， 各 LED串分别与限流电阻串联， 当主侦测模块测得某一 LED串电路中的限流电阻电压值高于 设定值时， 反馈至主控制模块， 由主控制模块向所述 LED 串发送关闭侦测指令， 控制关闭 对相应的 LED串的侦测， 并控制 LED串驱动输出端的输出电压降低。
0、 根据权利要求 9 所述的过压保护电路， 其中： 所述从侦测模块与各 LED 串分别电连 接， 所述各 LED串分别与限流电阻串联， 当从侦测模块测得某一 LED串电路中的限流电阻 高于设定值时， 反馈至从控制模块， 由从控制模块向所述 LED串发送关闭侦测指令， 控制 关闭对相应的 LED串的侦测； 所述主 IC和从 IC分别对各 LED串的通断进行负反馈控制。1、 一种采用如权利要求 1所述的过压保护电路的过压保护方法， 其中， 包括以下步骤：
步骤 1 )在主 IC过压触发电路和从 IC过压触发电路中，设置主 IC和从 IC的过压保护触发 点， 所述从 IC的过压保护触发点的电压低于主 IC的过压保护触发点的电压；
步骤 2)随着输出电压的上升， 当从 IC的从侦测模块检测到从分压电阻上的电压与从 IC的 过压保护触发点比较：
若从分压电阻上的电压达到从 IC的过压保护触发点时，从控制模块向出现开路的 LED串发 送关闭侦测指令， 控制关闭对相应的 LED串的电流 /电压侦测；
步骤 3 ) 当主 IC的主侦测模块检测到主分压电阻上的电压与主 IC的过压保护触发点比较： 若主分压电阻上的电压达到主 IC的过压保护触发点时，主控制模块向出现开路的 LED串发 送关闭指令， 控制相应的 LED串关闭， 并驱动输出电压降低；
步骤 4) 主控制模块根据主侦测模块的反馈值， 调整 LED驱动输出端的电压调整幅度。 、 根据权利要求 11所述的过压保护方法， 其中： 步骤 4) 进一步包括以下步骤：
步骤 41 ) 主控制模块根据主侦测模块的反馈值， 需要提高输出电压时， 则由主控制模块发 送升压控制信号至 MOS管， 驱动 MOS管提高占空比， 使其驱动 LED驱动输出端的电压上 升幅度；
步骤 42)若需要降低输出电压时，则由主控制模块发送降压控制信号至 MOS管，驱动 MOS 管降低占空比， 使其驱动 LED驱动输出端的电压下降幅度。 、一种面板驱动电路，其中：包括带主 IC和从 IC的 LED串、及用于对带主 IC和从 IC的 LED 串的驱动输出端电压进行调节的如权利要求 1所述的过压保护电路。
PCT/CN2013/078484 2013-05-17 2013-06-29 一种过压保护电路、过压保护方法及面板驱动电路 Ceased WO2014183329A1 (zh)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107845367A (zh) * 2017-11-13 2018-03-27 合肥惠科金扬科技有限公司 多功能led背光驱动电路及显示设备

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016009537A (ja) * 2014-06-23 2016-01-18 三菱電機株式会社 光源制御装置および光源制御方法
KR102360117B1 (ko) * 2014-12-30 2022-02-07 주식회사 엘엑스세미콘 리어 콤비네이션 램프 장치 및 그 감시 방법
CN105406700A (zh) * 2015-12-21 2016-03-16 中国科学院广州能源研究所 一种光伏逆变器母线电容均压及母线过压保护控制电路及系统
US10111299B2 (en) 2016-05-31 2018-10-23 Infineon Technologies Ag Adaptive overvoltage protection for multifunction LED chain
CN107978281B (zh) 2017-12-12 2020-11-10 北京京东方光电科技有限公司 一种背光模组驱动方法、装置以及显示装置
CN109755923B (zh) * 2019-02-20 2021-01-19 广州视源电子科技股份有限公司 一种电源装置的保护电路、方法及设备
CN113498234B (zh) * 2020-04-01 2023-05-12 炬芯科技股份有限公司 Mos管驱动电路及增强型led驱动电路
EP4159007B1 (en) * 2020-05-25 2023-10-25 Signify Holding B.V. Automatic length detection lighting device
DE102022131083A1 (de) * 2022-11-24 2024-05-29 Infineon Technologies Ag Fahrzeug, Fehlerüberwachungsvorrichtung für ein Fahrzeug und Halbleitervorrichtung zur Detektion einer Überspannung und/oder eines Überstroms

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2925000Y (zh) * 2006-06-23 2007-07-18 宁波日兴电子有限公司 音频电流led灯控制器
CN102750920A (zh) * 2012-07-02 2012-10-24 深圳市华星光电技术有限公司 一种led背光驱动电路、背光模组及液晶显示装置
CN103037589A (zh) * 2012-12-26 2013-04-10 深圳创维－Rgb电子有限公司 一种led恒流驱动电路及液晶电视
KR20130044102A (ko) * 2011-10-21 2013-05-02 엘지이노텍 주식회사 Ｌｅｄ 구동장치

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6597179B2 (en) * 1999-11-19 2003-07-22 Gelcore, Llc Method and device for remote monitoring of LED lamps
US20090021871A1 (en) * 2001-10-04 2009-01-22 Ise Corporation Energy Storage Pack Having Overvoltage Protection and Method of Protection
KR100867551B1 (ko) * 2007-05-18 2008-11-10 삼성전기주식회사 Ｌｅｄ 어레이 구동 장치
US8405321B2 (en) * 2007-07-26 2013-03-26 Rohm Co., Ltd. Drive unit, smoothing circuit, DC/DC converter
US20130193879A1 (en) * 2010-05-10 2013-08-01 Innosys, Inc. Universal Dimmer
US8773031B2 (en) * 2010-11-22 2014-07-08 Innosys, Inc. Dimmable timer-based LED power supply
US20130169165A1 (en) * 2011-12-15 2013-07-04 Laurence P. Sadwick Multi-Phase Lighting Driver
US9425608B2 (en) * 2011-12-20 2016-08-23 Kohler Co. Overvoltage protection system and method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2925000Y (zh) * 2006-06-23 2007-07-18 宁波日兴电子有限公司 音频电流led灯控制器
KR20130044102A (ko) * 2011-10-21 2013-05-02 엘지이노텍 주식회사 Ｌｅｄ 구동장치
CN102750920A (zh) * 2012-07-02 2012-10-24 深圳市华星光电技术有限公司 一种led背光驱动电路、背光模组及液晶显示装置
CN103037589A (zh) * 2012-12-26 2013-04-10 深圳创维－Rgb电子有限公司 一种led恒流驱动电路及液晶电视

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107845367A (zh) * 2017-11-13 2018-03-27 合肥惠科金扬科技有限公司 多功能led背光驱动电路及显示设备
CN107845367B (zh) * 2017-11-13 2024-02-20 合肥惠科金扬科技有限公司 多功能led背光驱动电路及显示设备

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