WO2018157418A1 - 一种保护电路及led驱动电路 - Google Patents

一种保护电路及led驱动电路 Download PDF

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Publication number
WO2018157418A1
WO2018157418A1 PCT/CN2017/077091 CN2017077091W WO2018157418A1 WO 2018157418 A1 WO2018157418 A1 WO 2018157418A1 CN 2017077091 W CN2017077091 W CN 2017077091W WO 2018157418 A1 WO2018157418 A1 WO 2018157418A1
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WO
WIPO (PCT)
Prior art keywords
resistor
switch
unit
control
switch tube
Prior art date
Application number
PCT/CN2017/077091
Other languages
English (en)
French (fr)
Inventor
杨勇
刘方云
Original Assignee
深圳市华星光电技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 深圳市华星光电技术有限公司 filed Critical 深圳市华星光电技术有限公司
Priority to ES17898762T priority Critical patent/ES2946002T3/es
Priority to KR1020197026176A priority patent/KR102215378B1/ko
Priority to US15/567,481 priority patent/US10278257B2/en
Priority to JP2019544827A priority patent/JP6737458B2/ja
Priority to EP17898762.4A priority patent/EP3592117B1/en
Priority to PL17898762.4T priority patent/PL3592117T3/pl
Publication of WO2018157418A1 publication Critical patent/WO2018157418A1/zh

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
    • H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
    • H03K17/0822—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in field-effect transistor switches
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/38—Switched mode power supply [SMPS] using boost topology
    • 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
    • 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
    • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
    • 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
    • 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

  • the present invention relates to the field of switching power supplies, and in particular, to a protection circuit and an LED driving circuit.
  • FIG. 1 is a system block diagram of an LED backlight module provided by the prior art.
  • the LED backlight module comprises: a rectification filter module, a DC-DC conversion module, a high frequency rectification filter module, a boost circuit 101, an LED load, and an output feedback module.
  • the existing LED backlight module system generally uses a 220V AC U_vin through a rectification filter module, a DC-DC conversion module, and a high frequency rectification filter module to output a first power source U1 and a second power source U2, usually for the second power source U2.
  • the first power source U1 is used to drive the LED load.
  • FIG. 2 is a schematic circuit diagram of the existing boosting circuit 101 and the LED load.
  • the boosting circuit 101 is configured to pull up the first power source U1 and provide the LED load.
  • the boosting circuit 101 includes an LED driving chip M1 and a switching transistor Q1.
  • the first power source U1 is further
  • the LED driver chip M1 is supplied with a startup voltage. However, since the driving voltage of the LED driver chip M1 is wide, it can operate at a lower voltage. When the first power source U1 is low, the LED driver chip M1 starts to work. Therefore, the current flowing through the switching transistor Q1 is excessively large, thereby damaging the switching transistor Q1, and reducing the reliability of the LED driving circuit.
  • the invention provides a protection circuit comprising:
  • a Zener diode a voltage dividing unit, a first switching unit, and a second switching unit
  • a cathode of the Zener diode is connected to a first power source, and an anode of the Zener diode is connected to an input end of the voltage dividing unit;
  • a control end of the first switch unit is connected to an output end of the voltage dividing unit, an input end of the first switch unit is connected to a second power source, an output end of the first switch unit and the second switch unit
  • the control terminal is connected, the first switch unit is configured to output a second control signal to the control end of the second switch unit under the control of the first control signal outputted by the output end of the voltage dividing unit;
  • An input end of the second switch unit is connected to the second power source, an output end of the second switch unit is connected to a boost circuit, and the second switch unit is configured to be under the control of the second control signal, Outputting a voltage to the boosting circuit;
  • the boosting circuit includes an LED driving chip, an output end of the second switching unit is connected to a starting end of the LED driving chip, and an input end of the boosting circuit is connected to the first power source for pulling Raising the voltage of the first power output;
  • the voltage dividing unit includes a first resistor and a second resistor
  • a first end of the first resistor is connected to an anode of the Zener tube, and a second end of the first resistor is connected to a first end of the second resistor and a control end of the first switch unit; The second end of the second resistor is grounded.
  • the first switching unit includes a third resistor, a fourth resistor, a first capacitor, and a first switching transistor;
  • a first end of the third resistor is connected to an output end of the voltage dividing unit, and a second end of the third resistor is connected to a first end of the first capacitor and a control end of the first switch tube The second end of the first capacitor is grounded;
  • the first end of the fourth resistor is connected to the second power source, and the second end of the fourth resistor is connected to the first end of the first switch tube and the control end of the second switch unit.
  • the second end of the first switch tube is grounded.
  • the second switching unit includes a fifth resistor and a second switching tube
  • the first end of the fifth resistor is connected to the second power source, and the second end of the fifth resistor is connected to the first end of the second switch tube and the boosting circuit;
  • the control end of the second switch tube is connected to the control end of the second switch unit, and the second end of the second switch tube is grounded.
  • the first switch tube and the second switch tube are NPN type transistors, wherein the control end, the first end, and the second end of the first switch tube and the second switch tube respectively It is the base, collector, and emitter.
  • the first switching unit includes a third resistor, a fourth resistor, a fifth resistor, a first capacitor, and a first switching transistor;
  • a first end of the third resistor is connected to an output end of the voltage dividing unit, and a second end of the third resistor is connected to a first end of the first capacitor and a control end of the first switch tube The second end of the first capacitor is grounded;
  • a first end of the fourth resistor is connected to the second power source, and a second end of the fourth resistor is connected to a first end of the fifth resistor and a control end of the second switch unit, The second end of the fifth resistor is connected to the first end of the first switch tube, and the second end of the first switch tube is grounded.
  • the second switching unit includes a second switching tube
  • the first end of the second switch tube is connected to the second power source, the control end of the second switch tube is connected to the first end of the fifth resistor, and the second end of the second switch tube is The boost circuit is connected.
  • the first switch tube is an NPN type transistor
  • the second switch tube is a PNP type transistor; wherein the control end, the first end, and the second end of the first switch tube
  • the base, the collector and the emitter are respectively the control end, the first end and the second end of the second switch tube are a base, an emitter and a collector, respectively.
  • the invention also provides a protection circuit comprising:
  • a Zener diode a voltage dividing unit, a first switching unit, and a second switching unit
  • a cathode of the Zener diode is connected to a first power source, and an anode of the Zener diode is connected to an input end of the voltage dividing unit;
  • a control end of the first switch unit is connected to an output end of the voltage dividing unit, an input end of the first switch unit is connected to a second power source, an output end of the first switch unit and the second switch unit
  • the control terminal is connected, the first switch unit is configured to output a second control signal to the control end of the second switch unit under the control of the first control signal outputted by the output end of the voltage dividing unit;
  • An input end of the second switch unit is connected to the second power source, an output end of the second switch unit is connected to a boost circuit, and the second switch unit is configured to be under the control of the second control signal, A voltage is output to the boost circuit.
  • the boosting circuit includes an LED driving chip, and an output end of the second switching unit is connected to a starting end of the LED driving chip, and an input end of the boosting circuit is The first power connection is used to pull up the voltage of the first power output.
  • the voltage dividing unit includes a first resistor and a second resistor
  • a first end of the first resistor is connected to an anode of the Zener tube, and a second end of the first resistor is connected to a first end of the second resistor and a control end of the first switch unit; The second end of the second resistor is grounded.
  • the first switching unit includes a third resistor, a fourth resistor, a first capacitor, and a first switching transistor;
  • a first end of the third resistor is connected to an output end of the voltage dividing unit, and a second end of the third resistor is connected to a first end of the first capacitor and a control end of the first switch tube The second end of the first capacitor is grounded;
  • the first end of the fourth resistor is connected to the second power source, and the second end of the fourth resistor is connected to the first end of the first switch tube and the control end of the second switch unit.
  • the second end of the first switch tube is grounded.
  • the second switching unit includes a fifth resistor and a second switching tube
  • the first end of the fifth resistor is connected to the second power source, and the second end of the fifth resistor is connected to the first end of the second switch tube and the boosting circuit;
  • the control end of the second switch tube is connected to the control end of the second switch unit, and the second end of the second switch tube is grounded.
  • the first switch tube and the second switch tube are NPN type transistors, wherein the control end, the first end, and the second end of the first switch tube and the second switch tube respectively It is the base, collector, and emitter.
  • the first switching unit includes a third resistor, a fourth resistor, a fifth resistor, a first capacitor, and a first switching transistor;
  • a first end of the third resistor is connected to an output end of the voltage dividing unit, and a second end of the third resistor is connected to a first end of the first capacitor and a control end of the first switch tube The second end of the first capacitor is grounded;
  • a first end of the fourth resistor is connected to the second power source, and a second end of the fourth resistor is connected to a first end of the fifth resistor and a control end of the second switch unit, The second end of the fifth resistor is connected to the first end of the first switch tube, and the second end of the first switch tube is grounded.
  • the second switching unit includes a second switching tube
  • the first end of the second switch tube is connected to the second power source, the control end of the second switch tube is connected to the first end of the fifth resistor, and the second end of the second switch tube is The boost circuit is connected.
  • the first switch tube is an NPN type transistor
  • the second switch tube is a PNP type transistor; wherein the control end, the first end, and the second end of the first switch tube are respectively The base, the collector and the emitter are the base, the emitter and the collector of the control terminal, the first end and the second end of the second switch.
  • an LED driving circuit includes a protection circuit and a boosting circuit connected to the protection circuit.
  • the protection circuit includes:
  • a Zener diode a voltage dividing unit, a first switching unit, and a second switching unit
  • a cathode of the Zener diode is connected to a first power source, and an anode of the Zener diode is connected to an input end of the voltage dividing unit;
  • a control end of the first switch unit is connected to an output end of the voltage dividing unit, an input end of the first switch unit is connected to a second power source, an output end of the first switch unit and the second switch unit
  • the control terminal is connected, the first switch unit is configured to output a second control signal to the control end of the second switch unit under the control of the first control signal outputted by the output end of the voltage dividing unit;
  • An input end of the second switch unit is connected to the second power source, an output end of the second switch unit is connected to a boost circuit, and the second switch unit is configured to be under the control of the second control signal, A voltage is output to the boost circuit.
  • the boosting circuit includes an LED driving chip, and an output end of the second switching unit is connected to a starting end of the LED driving chip, and an input end of the boosting circuit is The first power connection is used to pull up the voltage of the first power output.
  • the voltage dividing unit includes a first resistor and a second resistor
  • a first end of the first resistor is connected to an anode of the Zener tube, and a second end of the first resistor is connected to a first end of the second resistor and a control end of the first switch unit; The second end of the second resistor is grounded.
  • the protection circuit and the LED driving circuit of the present invention are different from the prior art in that the present invention does not directly provide a starting voltage to the boosting circuit through the first power source, but sets a protection circuit, and the first switching unit of the protection circuit Controlling, by the first control signal, outputting the second control signal to the second switching unit, wherein the second switching unit outputs the voltage to the boosting circuit under the control of the second control signal, so that only the voltage provided by the first power source At a certain value, the voltage is output to the booster circuit to operate the booster circuit, thereby improving the reliability of the circuit.
  • FIG. 1 is a system block diagram of an LED backlight module provided by the prior art
  • FIG. 2 is a circuit schematic diagram of a conventional booster circuit 101 and an LED load
  • FIG. 3 is a system block diagram of an LED backlight module provided by the present invention.
  • FIG. 4 is a circuit schematic diagram of a booster circuit 201 and an LED load of the present invention.
  • Figure 5 is a circuit schematic diagram of a first preferred embodiment of the protection circuit of the present invention.
  • Figure 6 is a circuit schematic diagram of a second preferred embodiment of the protection circuit of the present invention.
  • FIG. 3 is a system block diagram of an LED backlight module provided by the present invention.
  • the LED backlight module of the present invention comprises: a rectification filtering module, a DC-DC conversion module, a high frequency rectification filtering module, a boosting circuit 201, an LED load, a protection circuit 202, and an output feedback module.
  • the LED backlight module system of the present invention generally uses a 220V AC U_vin through a rectification filter module, a DC-DC conversion module, and a high frequency rectification filter module to output a first power source U1 and a second power source U2, and the second power source U2 is used for The movement/CB drive, the first power source U1 and the second power source U2 output a voltage to the booster circuit 201 under the control of the protection circuit 202, thereby driving the LED load.
  • FIG. 4 is a circuit schematic diagram of the booster circuit 201 and the LED load of the present invention.
  • the input end of the boosting circuit of the present invention is connected to the first power source U1.
  • the boosting circuit of the present invention further includes an LED driving chip M2 and a switching transistor Q2, wherein the LED driving chip The start end of the M2 is connected to the output terminal VIN of the second switch unit, the control end of the switch tube Q2 is connected to the adjustment control terminal SW of the LED drive chip M2, and the first end of the switch tube Q2 is connected to the output of the first power source Q1.
  • the second end of the switching transistor Q2 is connected to the feedback terminal CS of the LED driving chip M2.
  • the LED driving chip M2 When the LED driving chip M2 receives a starting voltage from the output terminal VIN of the second switching unit, the LED driving chip M2 operates, and the control switch tube Q2 is adjusted through the SW terminal of the LED driving chip M2; when the switching tube Q2 is turned on, the inductance L1 energy storage, when the inductor L1 will store the stored energy, the output voltage value of the OVP terminal of the LED driver chip M2 is driven to drive the LED load.
  • FIG. 5 is a circuit schematic diagram of a first preferred embodiment of the protection circuit of the present invention.
  • the protection circuit includes a Zener diode D1, a voltage dividing unit 501, a first switching unit 502, and a second switching unit 503.
  • the cathode of the Zener diode D1 is connected to the first power source U1, and the anode of the Zener diode D1. Connected to the input of the voltage dividing unit 501.
  • the control end of the first switch unit 502 is connected to the output end of the voltage dividing unit 501, the input end of the first switch unit 502 is connected to the second power source U2, and the output end of the first switch unit 502 is connected to the control end of the second switch unit 503.
  • the first switching unit 502 is configured to output a second control signal to the control end of the second switching unit 503 under the control of the first control signal outputted by the output of the voltage dividing unit 501.
  • the input end of the second switch unit 503 is connected to the second power source U2, the output end VIN of the second switch unit 503 is connected to the booster circuit, and the second switch unit 503 is configured to output a voltage to the control under the control of the second control signal.
  • the boost circuit is configured to output a voltage to the control under the control of the second control signal.
  • the voltage dividing unit 501 includes a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the anode of the Zener diode D1, and the second end of the first resistor R1 and the second resistor R2 are One end is connected to the control end of the first switching unit 502; the second end of the second resistor R2 is grounded.
  • the first switch unit 502 includes a third resistor R3, a fourth resistor R4, a first capacitor C1, and a first switch transistor Q3.
  • the first end of the third resistor R3 is connected to the output end of the voltage dividing unit 501, and the third resistor R3 is The second end is connected to the first end of the first capacitor C1 and the control end of the first switch tube Q3; the second end of the first capacitor C1 is grounded; the first end of the fourth resistor R4 is connected to the second power source U2, fourth The second end of the resistor R4 is connected to the first end of the first switch tube Q3 and the control end of the second switch unit 503, and the second end of the first switch tube Q3 is grounded.
  • the second switch unit 503 includes a fifth resistor and a second switch Q4; the first end of the fifth resistor R5 is coupled to the second power source U2, the second end of the fifth resistor R5 is coupled to the first end of the second switch tube Q4, and The boosting circuit is connected; the control end of the second switching transistor Q4 is connected to the control end of the second switching unit 503, and the second end of the second switching transistor Q4 is grounded.
  • the first switch tube Q3 and the second switch tube Q4 are NPN type transistors; the control end, the first end and the second end of the first switch tube and the second switch tube are respectively a base, a collector and an emitter.
  • the protection circuit further includes a second capacitor C2.
  • the first end of the second capacitor C2 is connected to the output terminal VIN of the second switch unit 503, and the second end of the second capacitor C2 is grounded.
  • the working circuit of the protection circuit is as follows: when the voltage outputted by the first power source U1 is greater than the voltage regulation value of the voltage regulator D1, the voltage regulator D1 is turned on, and the voltage output by the first power source U1 is input through the voltage dividing unit 501.
  • the terminal flows in, and then outputs the first control signal to the control end of the first switching unit 502 through the output end of the voltage dividing unit 501, so that the first switching transistor Q3 is turned on; the second power source U2 passes through the fourth resistor R4 and the first switch.
  • the tube Q3 is output to the ground, so that the control end of the second switch unit 503 receives the second control signal, so that the second switch tube Q4 is turned off, and the second power source U2 outputs a voltage to the second through the input end of the second switch unit 503.
  • the output terminal VIN of the switch unit 503 similarly, when the voltage outputted by the first power source U1 is less than the voltage regulator value of the Zener diode D1, the Zener diode D1 is turned off, the first switch transistor Q3 is turned off, and the second switch transistor Q4 is turned on.
  • the second power source U2 is output to the ground through the input end of the second switching unit 503, and the output terminal VIN of the second switching unit 503 has no voltage output.
  • FIG. 6 is a circuit schematic diagram of a second preferred embodiment of the protection circuit of the present invention.
  • the protection circuit includes a Zener diode D1, a voltage dividing unit 601, a first switching unit 602, and a second switching unit 603; the cathode terminal of the Zener diode D1 is connected to the first power source U1, and the Zener diode D1 The anode end is connected to the input end of the voltage dividing unit 601.
  • the control end of the first switch unit 602 is connected to the output end of the voltage dividing unit 601, the input end of the first switch unit 602 is connected to the second power source U2, and the output end of the first switch unit 602 is connected to the control end of the second switch unit 603.
  • the first switching unit 602 is configured to output a second control signal to the control end of the second switching unit 603 under the control of the first control signal outputted by the output of the voltage dividing unit 601.
  • the input end of the second switch unit 603 is connected to the second power source U2, the output end of the second switch unit 603 is connected to the boost circuit, and the second switch unit 603 is used to output a voltage to the boost under the control of the second control signal.
  • the circuit makes the boost circuit work.
  • the voltage dividing unit 601 includes a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the anode of the Zener diode D1, and the second end of the first resistor R1 and the second resistor R2 are One end is connected to the control end of the first switching unit 602; the second end of the second resistor R2 is grounded.
  • the first switch unit 602 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, and a first switch transistor Q3.
  • the first end of the third resistor R3 is connected to the output end of the voltage dividing unit 601.
  • the second end of the third resistor R3 is connected to the first end of the first capacitor C1 and the control end of the first switch tube Q3; the second end of the first capacitor C1 is grounded; the first end of the fourth resistor R4 is connected to the second power source U2 is connected, the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5 and the control end of the second switch unit 603, and the second end of the fifth resistor R5 is connected to the first end of the first switch tube Q3 The second end of the first switching transistor Q3 is grounded.
  • the second switch unit 603 includes a second switch tube Q4; the first end of the second switch tube Q4 is connected to the second power source U2, and the control end of the second switch tube Q4 is connected to the first end of the fifth resistor R5, the second switch The second end of the tube Q4 is connected to the booster circuit.
  • the first switch tube Q3 is an NPN type triode
  • the second switch tube Q4 is a PNP type triode
  • the control end, the first end and the second end of the first switch tube Q3 are a base, a collector, and an emitter, respectively.
  • the control end, the first end and the second end of the second switch Q4 are a base, an emitter and a collector, respectively.
  • the protection circuit further includes a second capacitor C2.
  • the first end of the second capacitor C2 is connected to the output terminal VIN of the second switch unit 603, and the second end of the second capacitor C2 is grounded.
  • the working circuit of the protection circuit is as follows: when the voltage outputted by the first power source U1 is greater than the voltage regulation value of the Zener diode D1, the Zener diode D1 is turned on, and the voltage output by the first power source U1 is input through the input terminal of the voltage dividing unit 601. After flowing in, the output terminal of the voltage dividing unit 601 outputs a first control signal to the control end of the first switching unit 602, so that the first switching transistor Q3 is turned on; the second power source U2 passes through the fourth resistor R4 and the fifth resistor R5.
  • the first switch tube Q3 is output to the ground end, so that the control end of the second switch unit 603 receives the second control signal, so that the second switch tube Q4 is turned on, and the second power source U2 is output through the input end of the second switch unit 603. a voltage to the output terminal VIN of the second switching unit 603; likewise, when the voltage output by the first power source U1 is less than the voltage regulator value of the Zener diode D1, the Zener diode D1 is turned off, the first switching transistor Q3 is turned off, and the second switch The tube Q4 is turned off, and the output terminal VIN of the second switching unit 603 has no voltage output.
  • the protection circuit of the present invention provides a protection circuit, through the control action of the first switching tube and the second switching tube, so that only when the voltage supplied by the first power source is at a certain value, the voltage is output to the LED driving chip, thereby improving The reliability of the circuit.
  • the present invention also provides an LED driving circuit, which includes the protection circuit of the above embodiment.
  • the protection circuit has been discussed in detail in the above embodiments, and details are not described herein again.
  • the LED driving circuit of the present invention is provided with a protection circuit, and the control function of the first switching unit and the second switching unit is such that the voltage is output to the LED driving chip only when the voltage supplied by the first power source is at a certain value, thereby Improve the reliability of the circuit.

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Abstract

本发明提供一种保护电路及LED驱动电路，包括稳压二极管、分压单元、第一开关单元以及第二开关单元；稳压二极管的阴极、阳极分别连接第一电源、分压单元的输入端；第一开关单元的控制端、输入端、输出端分别连接至分压单元的输出端、第二电源、第二开关单元的控制端；第二开关单元的输入端、输出端分别连接第二电源、升压电路。

Description

一种保护电路及LED驱动电路 技术领域
本发明涉及开关电源技术领域，尤其涉及一种保护电路及LED驱动电路。
 背景技术
参阅图1，图1为现有技术提供的LED背光模组的系统框图。如图1所示，该LED背光模组包括：整流滤波模块、DC-DC转换模块、高频整流滤波模块、升压电路101、LED负载以及输出反馈模块。现有的LED背光模组系统，通常是将220V交流电U_vin通过整流滤波模块、DC-DC转换模块以及高频整流滤波模块，从而输出第一电源U1以及第二电源U2，通常第二电源U2用于机芯/CB驱动，第一电源U1用于驱动LED负载。
而现有的升电路通常配合LED驱动芯片驱动LED负载，参阅图2，图2为现有的升压电路101以及LED负载的电路原理图。如图2所示，该升压电路101用于拉升第一电源U1，再提供给LED负载，该升压电路101包括一LED驱动芯片M1以及一开关管Q1，其中，第一电源U1还为LED驱动芯片M1提供启动电压，然而，由于LED驱动芯片M1的启动电压的范围较宽，在较低的电压下就能工作，当第一电源U1较低时，LED驱动芯片M1就开始工作，从而使得开关管Q1流过的电流过大，进而损坏开关管Q1，降低LED驱动电路的可靠性。
故，有必要提供一种保护电路及LED驱动电路，以解决现有技术所存在的问题。
 技术问题
本发明的目的在于提供一种保护电路及LED驱动电路，旨在提高现有的LED背光模组的可靠性。
 技术解决方案
本发明提供一种保护电路其包括：
稳压二极管、分压单元、第一开关单元以及第二开关单元；
所述稳压二极管的阴极连接第一电源，所述稳压二极管的阳极连接至所述分压单元的输入端；
所述第一开关单元的控制端连接至所述分压单元的输出端，所述第一开关单元的输入端连接第二电源，所述第一开关单元的输出端与所述第二开关单元的控制端连接，所述第一开关单元用于在所述分压单元的输出端输出的第一控制信号的控制下，输出第二控制信号至所述第二开关单元的控制端；
所述第二开关单元的输入端连接所述第二电源，所述第二开关单元的输出端连接至升压电路，所述第二开关单元用于在所述第二控制信号的控制下，输出一电压至所述升压电路；
所述升压电路包括一LED驱动芯片，所述第二开关单元的输出端与所述LED驱动芯片的启动端连接，所述升压电路的输入端与所述第一电源连接，用于拉升所述第一电源输出的电压；
所述分压单元包括第一电阻以及第二电阻；
所述第一电阻的第一端与所述稳压管的阳极连接，所述第一电阻的第二端与所述第二电阻的第一端以及所述第一开关单元的控制端连接；所述第二电阻的第二端接地。
在本发明的的保护电路中，所述第一开关单元包括第三电阻、第四电阻、第一电容以及第一开关管；
所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第一开关管的第一端以及所述第二开关单元的控制端连接，所述第一开关管的第二端接地。
在本发明的的保护电路中，所述第二开关单元包括第五电阻以及第二开关管；
所述第五电阻的第一端与所述第二电源连接，所述第五电阻的第二端与所述第二开关管的第一端以及所述升压电路连接；
所述第二开关管的控制端与所述第二开关单元的控制端连接，所述第二开关管的第二端接地。
在本发明的的保护电路中，所述第一开关管以及所述第二开关管为NPN型三极管，其中，第一开关管以及第二开关管的控制端、第一端、第二端分别为基极、集电极、发射极。
在本发明的的保护电路中，所述第一开关单元包括第三电阻、第四电阻、第五电阻、第一电容以及第一开关管；
所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第五电阻的第一端以及所述第二开关单元的控制端连接，所述第五电阻的第二端与所述第一开关管的第一端连接，所述第一开关管的第二端接地。
在本发明的的保护电路中，所述第二开关单元包括第二开关管；
所述第二开关管的第一端与所述第二电源连接，所述第二开关管的控制端与所述第五电阻的第一端连接，所述第二开关管的第二端与所述升压电路连接。
在本发明的的保护电路中，所述第一开关管为NPN型三极管，所述第二开关管为PNP型三极管；其中，所述第一开关管的控制端、第一端、第二端分别为基极、集电极、发射极，所述第二开关管的控制端、第一端、第二端分别为基极、发射极、集电极。
本发明还提供一种保护电路，其包括：
稳压二极管、分压单元、第一开关单元以及第二开关单元；
所述稳压二极管的阴极连接第一电源，所述稳压二极管的阳极连接至所述分压单元的输入端；
所述第一开关单元的控制端连接至所述分压单元的输出端，所述第一开关单元的输入端连接第二电源，所述第一开关单元的输出端与所述第二开关单元的控制端连接，所述第一开关单元用于在所述分压单元的输出端输出的第一控制信号的控制下，输出第二控制信号至所述第二开关单元的控制端；
所述第二开关单元的输入端连接所述第二电源，所述第二开关单元的输出端连接至升压电路，所述第二开关单元用于在所述第二控制信号的控制下，输出一电压至所述升压电路。
在本发明的的保护电路中，所述升压电路包括一LED驱动芯片，所述第二开关单元的输出端与所述LED驱动芯片的启动端连接，所述升压电路的输入端与所述第一电源连接，用于拉升所述第一电源输出的电压。
在本发明的的保护电路中，所述分压单元包括第一电阻以及第二电阻；
所述第一电阻的第一端与所述稳压管的阳极连接，所述第一电阻的第二端与所述第二电阻的第一端以及所述第一开关单元的控制端连接；所述第二电阻的第二端接地。
在本发明的的保护电路中，所述第一开关单元包括第三电阻、第四电阻、第一电容以及第一开关管；
所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第一开关管的第一端以及所述第二开关单元的控制端连接，所述第一开关管的第二端接地。
在本发明的的保护电路中，所述第二开关单元包括第五电阻以及第二开关管；
所述第五电阻的第一端与所述第二电源连接，所述第五电阻的第二端与所述第二开关管的第一端以及所述升压电路连接；
所述第二开关管的控制端与所述第二开关单元的控制端连接，所述第二开关管的第二端接地。
在本发明的的保护电路中，所述第一开关管以及所述第二开关管为NPN型三极管，其中，第一开关管以及第二开关管的控制端、第一端、第二端分别为基极、集电极、发射极。
在本发明的的保护电路中，所述第一开关单元包括第三电阻、第四电阻、第五电阻、第一电容以及第一开关管；
所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第五电阻的第一端以及所述第二开关单元的控制端连接，所述第五电阻的第二端与所述第一开关管的第一端连接，所述第一开关管的第二端接地。
在本发明的的保护电路中，所述第二开关单元包括第二开关管；
所述第二开关管的第一端与所述第二电源连接，所述第二开关管的控制端与所述第五电阻的第一端连接，所述第二开关管的第二端与所述升压电路连接。
在本发明的保护电路中，所述第一开关管为NPN型三极管，所述第二开关管为PNP型三极管；其中，所述第一开关管的控制端、第一端、第二端分别为基极、集电极、发射极，所述第二开关管的控制端、第一端、第二端分别为基极、发射极、集电极。
依据本发明的上述目的，还提供一种LED驱动电路，其包括一保护电路，及与所述保护电路连接的升压电路；所述保护电路，包括：
稳压二极管、分压单元、第一开关单元以及第二开关单元；
所述稳压二极管的阴极连接第一电源，所述稳压二极管的阳极连接至所述分压单元的输入端；
所述第一开关单元的控制端连接至所述分压单元的输出端，所述第一开关单元的输入端连接第二电源，所述第一开关单元的输出端与所述第二开关单元的控制端连接，所述第一开关单元用于在所述分压单元的输出端输出的第一控制信号的控制下，输出第二控制信号至所述第二开关单元的控制端；
所述第二开关单元的输入端连接所述第二电源，所述第二开关单元的输出端连接至升压电路，所述第二开关单元用于在所述第二控制信号的控制下，输出一电压至所述升压电路。
在本发明的LED驱动电路中，所述升压电路包括一LED驱动芯片，所述第二开关单元的输出端与所述LED驱动芯片的启动端连接，所述升压电路的输入端与所述第一电源连接，用于拉升所述第一电源输出的电压。
在本发明的LED驱动电路中，所述分压单元包括第一电阻以及第二电阻；
所述第一电阻的第一端与所述稳压管的阳极连接，所述第一电阻的第二端与所述第二电阻的第一端以及所述第一开关单元的控制端连接；所述第二电阻的第二端接地。
 有益效果
本发明的保护电路及LED驱动电路，与现有技术的区别在于，本发明没有直接通过第一电源给升压电路提供启动电压，而是设置了一保护电路，该保护电路的第一开关单元在第一控制信号的控制下，输出第二控制信号至第二开关单元，进而第二开关单元在第二控制信号的控制下，输出电压至升压电路，使得只有在第一电源提供的电压在一定值时，才会输出电压给升压电路，使升压电路工作，从而提高了电路的可靠性。
 附图说明
为让本发明的上述内容能更明显易懂，下文特举优选实施例，并配合所附图式，作详细说明如下：
下面结合附图，通过对本发明的具体实施方式详细描述，将使本发明的技术方案及其它有益效果显而易见。
图1为现有技术提供的LED背光模组的系统框图；
图2为现有的升压电路101以及LED负载的电路原理图；
图3为本发明提供的LED背光模组的系统框图；
图4为本发明的升压电路201以及LED负载的电路原理图；
图5为本发明的保护电路的第一优选实施例的电路原理图；
图6为本发明的保护电路的第二优选实施例的电路原理图。
 本发明的最佳实施方式
为更进一步阐述本发明所采取的技术手段及其效果，以下结合本发明的优选实施例及其附图进行详细描述。显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
参阅图3，图3为本发明提供的LED背光模组的系统框图。如图3所示，本发明的LED背光模组包括：整流滤波模块、DC-DC转换模块、高频整流滤波模块、升压电路201、LED负载、保护电路202以及输出反馈模块。本发明的LED背光模组系统，通常是将220V交流电U_vin通过整流滤波模块、DC-DC转换模块以及高频整流滤波模块，从而输出第一电源U1以及第二电源U2，第二电源U2用于机芯/CB驱动，第一电源U1以及第二电源U2在保护电路202的控制下输出电压至升压电路201，进而驱动LED负载。
具体的，参阅图4，图4为本发明的升压电路201以及LED负载的电路原理图。如图4所示，本发明的升压电路的输入端与第一电源U1连接；进一步的，本发明的升压电路还包括一LED驱动芯片M2以及一开关管Q2，其中，该LED驱动芯片M2的启动端与第二开关单元的输出端VIN连接，该开关管的Q2的控制端与LED驱动芯片M2的调节控制端SW连接，开关管Q2的第一端接入第一电源Q1输出的电压，开关管Q2的第二端与LED驱动芯片M2的反馈端CS连接。当LED驱动芯片M2从第二开关单元的输出端VIN接收到一启动电压时，LED驱动芯片M2工作，通过LED驱动芯片M2的SW端调节控制开关管Q2；当开关管Q2导通时，电感L1储能，关断时电感L1将储存的能量输出，通过LED驱动芯片M2的OVP端输出电压值，从而驱动LED负载。
参阅图5，图5为本发明的保护电路的第一优选实施例的电路原理图。如图5所示，该保护电路包括稳压二极管D1、分压单元501、第一开关单元502以及第二开关单元503；稳压二极管D1的阴极连接第一电源U1，稳压二极管D1的阳极连接至分压单元501的输入端.。
第一开关单元502的控制端连接至分压单元501的输出端，第一开关单元502的输入端连接第二电源U2，第一开关单元502的输出端与第二开关单元503的控制端连接，第一开关单元502用于在分压单元501的输出端输出的第一控制信号的控制下，输出第二控制信号至第二开关单元503的控制端。
第二开关单元503的输入端连接第二电源U2，第二开关单元503的输出端VIN连接至升压电路，第二开关单元503用于在第二控制信号的控制下，输出一电压至所述升压电路。
具体地，分压单元501包括第一电阻R1以及第二电阻R2；第一电阻R1的第一端与稳压二极管D1的阳极连接，第一电阻R1的第二端与第二电阻R2的第一端以及第一开关单元502的控制端连接；第二电阻R2的第二端接地。
第一开关单元502包括第三电阻R3、第四电阻R4、第一电容C1以及第一开关管Q3；第三电阻R3的第一端与分压单元501的输出端连接，第三电阻R3的第二端与第一电容C1的第一端以及第一开关管Q3的控制端连接；第一电容C1的第二端接地；第四电阻R4的第一端与第二电源U2连接，第四电阻R4的第二端与第一开关管Q3的第一端以及第二开关单元503的控制端连接，第一开关管Q3的第二端接地。
第二开关单元503包括第五电阻以及第二开关管Q4；第五电阻R5的第一端与第二电源U2连接，第五电阻R5的第二端与第二开关管Q4的第一端以及升压电路连接；第二开关管Q4的控制端与第二开关单元503的控制端连接，第二开关管Q4的第二端接地。
其中，第一开关管Q3以及第二开关管Q4为NPN型三极管；第一开关管以及第二开关管的控制端、第一端、第二端分别为基极、集电极、发射极。
该保护电路还包括第二电容C2，第二电容C2的第一端与第二开关单元503的输出端VIN连接，第二电容C2的第二端接地。
该保护电路的工作原路如下：当第一电源U1输出的电压大于稳压管D1的稳压值时，该稳压管D1导通，第一电源U1输出的电压经分压单元501的输入端流入，再经分压单元501的输出端输出第一控制信号至第一开关单元502的控制端，从而使得第一开关管Q3导通；第二电源U2经第四电阻R4以及第一开关管Q3输出至接地端，使得第二开关单元503的控制端接收第二控制信号，使得第二开关管Q4关闭，第二电源U2经第二开关单元503的输入端，输出一电压至第二开关单元503的输出端VIN；同样，当第一电源U1输出的电压小于稳压管D1的稳压值时，该稳压管D1截止，第一开关管Q3关闭，第二开关管Q4导通，第二电源U2经第二开关单元503的输入端输出至接地端，第二开关单元503的输出端VIN无电压输出。
参阅图6，图6为本发明的保护电路的第二优选实施例的电路原理图。如图6所示，该保护电路包括稳压二极管D1、分压单元601、第一开关单元602以及第二开关单元603；稳压二极管D1的阴极端连接第一电源U1，稳压二极管D1的阳极端连接至分压单元601的输入端.。
第一开关单元602的控制端连接至分压单元601的输出端，第一开关单元602的输入端连接第二电源U2，第一开关单元602的输出端与第二开关单元603的控制端连接，第一开关单元602用于在分压单元601的输出端输出的第一控制信号的控制下，输出第二控制信号至第二开关单元603的控制端。
第二开关单元603的输入端连接第二电源U2，第二开关单元603的输出端连接至升压电路，第二开关单元603用于在第二控制信号的控制下，输出一电压至升压电路，使得该升压电路工作。
具体地，分压单元601包括第一电阻R1以及第二电阻R2；第一电阻R1的第一端与稳压管D1的阳极连接，第一电阻R1的第二端与第二电阻R2的第一端以及第一开关单元602的控制端连接；第二电阻R2的第二端接地。
第一开关单元602包括第三电阻R3、第四电阻R4、第五电阻R5、第一电容C1以及第一开关管Q3；第三电阻R3的第一端与分压单元601的输出端连接，第三电阻R3的第二端与第一电容C1的第一端以及第一开关管Q3的控制端连接；第一电容C1的第二端接地；第四电阻R4的第一端与第二电源U2连接，第四电阻R4的第二端与第五电阻R5的第一端以及第二开关单元603的控制端连接，第五电阻R5的第二端与第一开关管Q3的第一端连接，第一开关管Q3的第二端接地。
第二开关单元603包括第二开关管Q4；第二开关管Q4的第一端与第二电源U2连接，第二开关管Q4的控制端与第五电阻R5的第一端连接，第二开关管Q4的第二端与升压电路连接。
其中，第一开关管Q3为NPN型三极管，第二开关管Q4为PNP型三极管；第一开关管Q3的控制端、第一端、第二端分别为基极、集电极、发射极，第二开关管Q4的控制端、第一端、第二端分别为基极、发射极、集电极。
保护电路还包括第二电容C2，第二电容C2的第一端与第二开关单元603的输出端VIN连接，第二电容C2的第二端接地。
该保护电路的工作原路如下：当第一电源U1输出的电压大于稳压管D1的稳压值时，稳压管D1导通，第一电源U1输出的电压经分压单元601的输入端流入，再经分压单元601的输出端输出第一控制信号至第一开关单元602的控制端，从而使得第一开关管Q3导通；第二电源U2经第四电阻R4、第五电阻R5以及第一开关管Q3输出至接地端，使得第二开关单元603的控制端接收第二控制信号，使得第二开关管Q4导通，第二电源U2经第二开关单元603的输入端，输出一电压至第二开关单元603的输出端VIN；同样，当第一电源U1输出的电压小于稳压管D1的稳压值时，稳压管D1截止，第一开关管Q3关闭，第二开关管Q4关闭，第二开关单元603的输出端VIN无电压输出。
本发明的保护电路通过设置一保护电路，通过第一开关管以及第二开关管的控制作用，使得只有在第一电源提供的电压在一定值时，才会输出电压给LED驱动芯片，从而提高了电路的可靠性。
本发明还提供一种LED驱动电路，包括上述实施例的保护电路，该保护电路已经在上述实施例中进行了详细的论述，在此不再赘述。
本发明的LED驱动电路过设置一保护电路，通过第一开关单元以及第二开关单元的控制作用，使得只有在第一电源提供的电压在一定值时，才会输出电压给LED驱动芯片，从而提高了电路的可靠性。
综上，虽然本发明已以优选实施例揭露如上，但上述优选实施例并非用以限制本发明，本领域的普通技术人员，在不脱离本发明的精神和范围内，均可作各种更动与润饰，因此本发明的保护范围以权利要求界定的范围为准。

Claims (19)

  1. 一种保护电路，其包括：
    稳压二极管、分压单元、第一开关单元以及第二开关单元；
    所述稳压二极管的阴极连接第一电源，所述稳压二极管的阳极连接至所述分压单元的输入端；
    所述第一开关单元的控制端连接至所述分压单元的输出端，所述第一开关单元的输入端连接第二电源，所述第一开关单元的输出端与所述第二开关单元的控制端连接，所述第一开关单元用于在所述分压单元的输出端输出的第一控制信号的控制下，输出第二控制信号至所述第二开关单元的控制端；
    所述第二开关单元的输入端连接所述第二电源，所述第二开关单元的输出端连接至升压电路，所述第二开关单元用于在所述第二控制信号的控制下，输出一电压至所述升压电路；
    所述升压电路包括一LED驱动芯片，所述第二开关单元的输出端与所述LED驱动芯片的启动端连接，所述升压电路的输入端与所述第一电源连接，用于拉升所述第一电源输出的电压；
    所述分压单元包括第一电阻以及第二电阻；
    所述第一电阻的第一端与所述稳压管的阳极连接，所述第一电阻的第二端与所述第二电阻的第一端以及所述第一开关单元的控制端连接；所述第二电阻的第二端接地。
  2. 根据权利要求1所述的保护电路，其中所述第一开关单元包括第三电阻、第四电阻、第一电容以及第一开关管；
    所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
    所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第一开关管的第一端以及所述第二开关单元的控制端连接，所述第一开关管的第二端接地。
  3. 根据权利要求2所述的保护电路，其中所述第二开关单元包括第五电阻以及第二开关管；
    所述第五电阻的第一端与所述第二电源连接，所述第五电阻的第二端与所述第二开关管的第一端以及所述升压电路连接；
    所述第二开关管的控制端与所述第二开关单元的控制端连接，所述第二开关管的第二端接地。
  4. 根据权利要求3所述的保护电路，其中所述第一开关管以及所述第二开关管为NPN型三极管，其中，第一开关管以及第二开关管的控制端、第一端、第二端分别为基极、集电极、发射极。
  5. 根据权利要求1所述的保护电路，其中所述第一开关单元包括第三电阻、第四电阻、第五电阻、第一电容以及第一开关管；
    所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
    所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第五电阻的第一端以及所述第二开关单元的控制端连接，所述第五电阻的第二端与所述第一开关管的第一端连接，所述第一开关管的第二端接地。
  6. 根据权利要求5所述的保护电路，其中所述第二开关单元包括第二开关管；
    所述第二开关管的第一端与所述第二电源连接，所述第二开关管的控制端与所述第五电阻的第一端连接，所述第二开关管的第二端与所述升压电路连接。
  7. 根据权利要求6所述的保护电路，其中所述第一开关管为NPN型三极管，所述第二开关管为PNP型三极管；其中，所述第一开关管的控制端、第一端、第二端分别为基极、集电极、发射极，所述第二开关管的控制端、第一端、第二端分别为基极、发射极、集电极。
  8. 一种保护电路，其包括：
    稳压二极管、分压单元、第一开关单元以及第二开关单元；
    所述稳压二极管的阴极连接第一电源，所述稳压二极管的阳极连接至所述分压单元的输入端；
    所述第一开关单元的控制端连接至所述分压单元的输出端，所述第一开关单元的输入端连接第二电源，所述第一开关单元的输出端与所述第二开关单元的控制端连接，所述第一开关单元用于在所述分压单元的输出端输出的第一控制信号的控制下，输出第二控制信号至所述第二开关单元的控制端；
    所述第二开关单元的输入端连接所述第二电源，所述第二开关单元的输出端连接至升压电路，所述第二开关单元用于在所述第二控制信号的控制下，输出一电压至所述升压电路。
  9. 根据权利要求8所述的保护电路，其中所述升压电路包括一LED驱动芯片，所述第二开关单元的输出端与所述LED驱动芯片的启动端连接，所述升压电路的输入端与所述第一电源连接，用于拉升所述第一电源输出的电压。
  10. 根据权利要求8所述的保护电路，其中所述分压单元包括第一电阻以及第二电阻；
    所述第一电阻的第一端与所述稳压管的阳极连接，所述第一电阻的第二端与所述第二电阻的第一端以及所述第一开关单元的控制端连接；所述第二电阻的第二端接地。
  11. 根据权利要求8所述的保护电路，其中所述第一开关单元包括第三电阻、第四电阻、第一电容以及第一开关管；
    所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
    所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第一开关管的第一端以及所述第二开关单元的控制端连接，所述第一开关管的第二端接地。
  12. 根据权利要求11所述的保护电路，其中所述第二开关单元包括第五电阻以及第二开关管；
    所述第五电阻的第一端与所述第二电源连接，所述第五电阻的第二端与所述第二开关管的第一端以及所述升压电路连接；
    所述第二开关管的控制端与所述第二开关单元的控制端连接，所述第二开关管的第二端接地。
  13. 根据权利要求12所述的保护电路，其中所述第一开关管以及所述第二开关管为NPN型三极管，其中，第一开关管以及第二开关管的控制端、第一端、第二端分别为基极、集电极、发射极。
  14. 根据权利要求8所述的保护电路，其中所述第一开关单元包括第三电阻、第四电阻、第五电阻、第一电容以及第一开关管；
    所述第三电阻的第一端与所述分压单元的输出端连接，所述第三电阻的第二端与所述第一电容的第一端以及所述第一开关管的控制端连接；所述第一电容的第二端接地；
    所述第四电阻的第一端与所述第二电源连接，所述第四电阻的第二端与所述第五电阻的第一端以及所述第二开关单元的控制端连接，所述第五电阻的第二端与所述第一开关管的第一端连接，所述第一开关管的第二端接地。
  15. 根据权利要求14所述的保护电路，其中所述第二开关单元包括第二开关管；
    所述第二开关管的第一端与所述第二电源连接，所述第二开关管的控制端与所述第五电阻的第一端连接，所述第二开关管的第二端与所述升压电路连接。
  16. 根据权利要求15所述的保护电路，其中所述第一开关管为NPN型三极管，所述第二开关管为PNP型三极管；其中，所述第一开关管的控制端、第一端、第二端分别为基极、集电极、发射极，所述第二开关管的控制端、第一端、第二端分别为基极、发射极、集电极。
  17. 一种LED驱动电路，其包括一保护电路，及与所述保护电路连接的升压电路；所述保护电路，包括：
    稳压二极管、分压单元、第一开关单元以及第二开关单元；
    所述稳压二极管的阴极连接第一电源，所述稳压二极管的阳极连接至所述分压单元的输入端；
    所述第一开关单元的控制端连接至所述分压单元的输出端，所述第一开关单元的输入端连接第二电源，所述第一开关单元的输出端与所述第二开关单元的控制端连接，所述第一开关单元用于在所述分压单元的输出端输出的第一控制信号的控制下，输出第二控制信号至所述第二开关单元的控制端；
    所述第二开关单元的输入端连接所述第二电源，所述第二开关单元的输出端连接至升压电路，所述第二开关单元用于在所述第二控制信号的控制下，输出一电压至所述升压电路。
  18. 根据权利要求17所述的LED驱动电路，其中所述升压电路包括一LED驱动芯片，所述第二开关单元的输出端与所述LED驱动芯片的启动端连接，所述升压电路的输入端与所述第一电源连接，用于拉升所述第一电源输出的电压。
  19. 根据权利要求17所述的LED驱动电路，其中所述分压单元包括第一电阻以及第二电阻；
    所述第一电阻的第一端与所述稳压管的阳极连接，所述第一电阻的第二端与所述第二电阻的第一端以及所述第一开关单元的控制端连接；所述第二电阻的第二端接地。
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EP3592117B1 (en) 2023-03-15
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US10278257B2 (en) 2019-04-30
CN106849629A (zh) 2017-06-13

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