WO2022083203A1 - 消除cob封装光电效应的led驱动电路及驱动芯片 - Google Patents

消除cob封装光电效应的led驱动电路及驱动芯片 Download PDF

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Publication number
WO2022083203A1
WO2022083203A1 PCT/CN2021/108980 CN2021108980W WO2022083203A1 WO 2022083203 A1 WO2022083203 A1 WO 2022083203A1 CN 2021108980 W CN2021108980 W CN 2021108980W WO 2022083203 A1 WO2022083203 A1 WO 2022083203A1
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circuit
temperature
mos transistor
current
sub
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PCT/CN2021/108980
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English (en)
French (fr)
Inventor
叶羽安
邓迅升
王文攀
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深圳市晟碟半导体有限公司
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Publication of WO2022083203A1 publication Critical patent/WO2022083203A1/zh

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    • 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
    • H05B45/345—Current stabilisation; Maintaining constant current
    • 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
    • H05B45/56—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits involving measures to prevent abnormal temperature of the LEDs

Definitions

  • the utility model relates to the technical field of LED lighting, in particular to an LED driving circuit and a driving chip for eliminating the photoelectric effect of COB packaging.
  • the LED lamp bead is a light-emitting device, and the LED driver chip drives the LED lamp bead to emit light.
  • the LED lamp bead emits light
  • the bare chip is affected by the photons excited by the LED lamp bead, and the photoelectric effect occurs. This effect destroys the constant current circuit in the LED driver chip, making the constant current flowing through the LED light string abnormal.
  • the LED driver chip circuit is usually composed of basic circuits such as a voltage reference circuit, an over-temperature adjustment circuit, and a constant current circuit.
  • the over-temperature regulation circuit contains a BJT (Bipolar Junction Transistor: short for Bipolar Junction Transistor, also known as a semiconductor triode device) device, and the BE junction voltage of the BJT device is used to detect the temperature of the chip.
  • BJT Bipolar Junction Transistor: short for Bipolar Junction Transistor, also known as a semiconductor triode device
  • the BE junction voltage of the BJT device is used to detect the temperature of the chip.
  • the BE junction voltage will be reduced, resulting in misjudgment of the over-temperature protection, thus causing the constant current circuit to work abnormally.
  • the purpose of the present invention is to provide an LED drive circuit and a drive chip that eliminates the photoelectric effect of COB encapsulation, which can effectively solve the problem of the LED drive chip after the LED lamp beads and the LED drive chip are packaged by COB.
  • An LED drive circuit for eliminating the photoelectric effect of COB package which is connected to an LED light string, includes an over-temperature regulation circuit, a constant current circuit and a temperature detection circuit without a BJT device; the temperature detection circuit is connected with the over-temperature regulation circuit and is used for The current temperature value is detected, and when the current temperature value is greater than the preset value, the over-temperature detection signal is output to the over-temperature adjustment circuit; the over-temperature adjustment circuit is connected with the constant current circuit, and is used to output the adjustment signal to the constant current circuit according to the over-temperature detection signal ; The constant current circuit is used to adjust the current flowing through the LED light string according to the adjustment signal.
  • the LED driving circuit for eliminating the photoelectric effect of the COB package also includes a reference voltage circuit, which is connected with the constant current circuit and is used for providing a reference voltage for the constant current circuit.
  • the temperature detection circuit includes a temperature sampling sub-circuit, a temperature detection sub-circuit and a first trimming sub-circuit; the temperature sampling sub-circuit is connected with the temperature detection sub-circuit for detecting the current temperature value and adjusting the temperature.
  • the current temperature value is converted into a voltage value and output to the temperature detection sub-circuit;
  • the temperature detection sub-circuit is connected to the over-temperature adjustment circuit, and is used to detect that the current temperature value is greater than the preset value according to the voltage value and the reference voltage, and output the over-temperature detection signal to the over-temperature detection signal.
  • a temperature regulating circuit; the first trimming sub-circuit is connected with the temperature detecting sub-circuit, and is used for regulating the voltage value of the reference voltage.
  • the reference voltage circuit includes a starter circuit, a zero-temperature current sub-circuit, a zero-temperature voltage sub-circuit and a second trimming sub-circuit;
  • the starter circuit is connected to the zero-temperature current sub-circuit for providing The zero-temperature current sub-circuit provides the starting current;
  • the zero-temperature current sub-circuit is connected with the zero-temperature voltage sub-circuit for outputting the zero-temperature current to the zero-temperature voltage sub-circuit after starting according to the starting current;
  • the zero-temperature voltage sub-circuit is connected with the constant current circuit , which is used to output the reference voltage to the constant current circuit according to the zero-temperature current;
  • the second trimming sub-circuit is connected to the zero-temperature voltage sub-circuit for adjusting the voltage value of the reference voltage.
  • the temperature sampling sub-circuit includes a first MOS transistor, the gate of the first MOS transistor is connected to the drain of the first MOS transistor, the temperature detection sub-circuit and the first current source, the first MOS transistor The source of the tube is grounded.
  • the temperature sampling subcircuit includes a first resistor, one end of the first resistor is connected to the temperature detection subcircuit and the first current source, and the other end of the first resistor is grounded.
  • the temperature detection sub-circuit includes a first operational amplifier, a second operational amplifier, a second MOS tube and a second resistor; the non-inverting input terminal of the first operational amplifier is connected to the first voltage source, The inverting input terminal of the first operational amplifier is connected to one end of the second resistor and the source of the second MOS transistor, the gate of the second MOS transistor is connected to the output terminal of the first operational amplifier, and the drain of the second MOS transistor is connected to the overtemperature In the adjustment circuit, the other end of the second resistor is connected to the output end and the inverting input end of the second operational amplifier, and the non-inverting input end of the second operational amplifier is connected to the temperature sampling subcircuit and the first current source.
  • the over-temperature adjustment circuit includes a third MOS tube, a fourth MOS tube, a fifth MOS tube and a sixth MOS tube; the drain and gate of the third MOS tube and the fourth MOS tube
  • the gate of the tube is connected to the drain of the second MOS tube, the source of the third MOS tube is connected to the source of the fourth MOS tube; the drain of the fourth MOS tube is connected to the drain, the gate and the gate of the fifth MOS tube.
  • the gates of the six MOS tubes, the source of the fifth MOS tube are grounded, the source of the sixth MOS tube is grounded, and the drain of the sixth MOS tube is connected to the constant current circuit.
  • the over-temperature adjustment circuit includes a seventh MOS transistor, an eighth MOS transistor and a third resistor; the drain and gate of the seventh MOS transistor and the gate of the eighth MOS transistor are all connected The drain of the second MOS transistor, the source of the seventh MOS transistor are connected to the source of the eighth MOS transistor, the source of the eighth MOS transistor is connected to one end of the third resistor, and the other end of the third resistor is connected to the constant current circuit.
  • An LED driving chip for eliminating the photoelectric effect of COB packaging comprising the above-mentioned LED driving circuit for eliminating the photoelectric effect of COB packaging.
  • the LED driving circuit and driving chip provided by the present invention can eliminate the photoelectric effect of COB package.
  • the LED driving circuit is connected with the LED light string, and includes an over-temperature adjustment circuit, a constant current circuit and a temperature without setting the BJT device.
  • the temperature detection circuit is connected with the over-temperature adjustment circuit for detecting the current temperature value, and outputs an over-temperature detection signal to the over-temperature adjustment circuit when the current temperature value is greater than the preset value;
  • the over-temperature adjustment circuit is connected with the constant current circuit , is used to output the adjustment signal to the constant current circuit according to the over-temperature detection signal;
  • the constant current circuit is used to adjust the current flowing through the LED light string according to the adjustment signal;
  • the utility model is provided with a temperature detection circuit without a BJT device, thereby effectively avoiding Turn on the influence of photoelectric effect on LED driver chip, and solve the problem of abnormal operation of constant current circuit caused by photoelectric effect of LED lighting COB package.
  • Fig. 1 is the structural block diagram of the LED drive circuit that eliminates the photoelectric effect of COB encapsulation provided by the utility model;
  • Fig. 2 is the circuit schematic diagram of the first embodiment in the LED driving circuit for eliminating the photoelectric effect of COB package provided by the present invention
  • FIG. 3 is a circuit schematic diagram of a starter sub-circuit, a zero-temperature current sub-circuit and a zero-temperature voltage sub-circuit in the LED drive circuit for eliminating the photoelectric effect of COB encapsulation provided by the utility model;
  • Fig. 4 is the circuit schematic diagram of the second trimming sub-circuit in the LED driving circuit for eliminating the photoelectric effect of COB package provided by the utility model;
  • Fig. 5 is the circuit schematic diagram of the second embodiment in the LED driving circuit for eliminating the photoelectric effect of COB package provided by the present invention
  • Fig. 6 is the circuit schematic diagram of the third embodiment in the LED driving circuit for eliminating the photoelectric effect of COB package provided by the present invention.
  • FIG. 7 is a circuit schematic diagram of the fourth embodiment of the LED driving circuit for eliminating the photoelectric effect of the COB package provided by the present invention.
  • the purpose of this utility model is to provide an LED drive circuit and a drive chip that eliminates the photoelectric effect of COB encapsulation, which can effectively solve the problem that the LED lamp bead and the LED drive chip are encapsulated by COB, and the LED drive chip is provided with a BJT device and is affected by the photoelectric effect.
  • the LED driver chip for eliminating the photoelectric effect of COB packaging includes an LED driving circuit for eliminating the photoelectric effect of COB packaging, and the LED driver circuit is connected to the LED light string outside the LED driver chip.
  • the LED driver chip and the LED lamp bead are integrated through COB packaging; wherein, the LED driver circuit for eliminating the photoelectric effect of the COB packaging includes an over-temperature adjustment circuit 100, a constant current circuit 200, and a temperature detection device without BJT devices.
  • the temperature detection circuit 300 is connected to the over-temperature adjustment circuit 100 for detecting the current temperature value, and outputs an over-temperature detection signal to the over-temperature adjustment circuit 100 when the current temperature value is greater than the preset value; the over-temperature adjustment circuit 100 is connected to the over-temperature adjustment circuit 100.
  • the constant current circuit 200 is connected to output an adjustment signal to the constant current circuit 200 according to the over-temperature detection signal; the constant current circuit 200 is used to adjust the current flowing through the LED light string according to the adjustment signal;
  • the temperature detection circuit 300 detects the current temperature value of the LED driver chip, which is equivalent to not detecting the temperature of the LED driver chip with the BE junction voltage of the BJT device, thereby avoiding the influence of the photoelectric effect on the LED driver chip and solving the LED lighting COB package The problem that the constant current circuit works abnormally due to the photoelectric effect.
  • the LED driving circuit for eliminating the photoelectric effect of the COB package also includes a reference voltage circuit 400.
  • the reference voltage circuit 400 is connected to the constant current circuit 200 and is used to provide a reference voltage for the constant current circuit 200. Then, the constant current circuit 200 can adjust the reference voltage according to the reference voltage. Set the current flowing through the LED light string to make the LED light string work normally.
  • the temperature detection circuit 300 includes a temperature sampling sub-circuit 310, a temperature detection sub-circuit 320 and a first trimming sub-circuit 330; the temperature sampling sub-circuit 310 is connected with the temperature detection sub-circuit 320 for Detects the current temperature value and converts the current temperature value into a voltage value and outputs it to the temperature detection sub-circuit 320; the temperature detection sub-circuit 320 is connected to the over-temperature adjustment circuit 100 for detecting that the current temperature value is greater than the preset value according to the voltage value and the reference voltage output the over-temperature detection signal to the over-temperature adjustment circuit 100; the first trimming sub-circuit 330 is connected to the temperature detection sub-circuit 320 to adjust the voltage value of the reference voltage; in this embodiment, the temperature sampling sub-circuit 310, the temperature detection sub-circuit 310 Neither the circuit 320 nor the first trimming sub-circuit 330 is provided with a BJT device.
  • the temperature sampling sub-circuit 310 directly converts the temperature value of the LED driver chip into a voltage value, and the voltage value is negatively correlated with the temperature value.
  • the temperature value is larger, the voltage value is smaller; then , when the temperature detection sub-circuit 320 detects that the voltage value is less than the reference voltage, it indicates that the current temperature value is greater than the preset value, that is, the LED driver chip is over-temperature, and the current temperature value exceeds the over-temperature point temperature, then an over-temperature detection signal is output
  • the over-temperature adjustment circuit 100 outputs an adjustment signal related to the current temperature value of the LED driver chip according to the over-temperature detection signal and acts on the constant current circuit 200 to adjust the current output of the constant current circuit 200, that is, Adjust the current flowing through the LED light string; since the temperature sampling sub-circuit 310, the temperature detection sub-circuit 320 and the first trimming sub-circuit 330 are not provided with BJT devices, the non
  • the reference voltage circuit 400 includes a starter sub-circuit 410 , a zero-temperature current sub-circuit 420 , a zero-temperature voltage sub-circuit 430 and a second trimming sub-circuit 440 ;
  • the starter sub-circuit 410 is connected to the zero-temperature current sub-circuit 420 , used to provide the starting current to the zero-temperature current sub-circuit 420;
  • the zero-temperature current sub-circuit 420 is connected to the zero-temperature voltage sub-circuit 430, and is used to output the zero-temperature current to the zero-temperature voltage sub-circuit 430 after starting according to the starting current;
  • the voltage sub-circuit 430 is connected to the constant current circuit 200 for outputting a reference voltage to the constant current circuit 200 according to the zero-temperature current;
  • the second trimming sub-circuit 440 is connected to the zero-temperature voltage sub-circuit 430 for adjusting the voltage value of the reference voltage; After the reference voltage circuit 400 is powered on
  • the zero-temperature voltage sub-circuit 430 of 420 provides zero-temperature current, and the zero-temperature voltage sub-circuit 430 outputs the reference voltage to the constant current circuit according to the zero-temperature current, thereby realizing the output of the reference voltage; and the setting of the second trimming sub-circuit 440 can be The voltage value of the reference voltage is adjusted so as to satisfy the constant current setting of the subsequent constant current circuit 200 .
  • the temperature sampling sub-circuit 310 includes a first MOS transistor M1, the gate of the first MOS transistor M1 is connected to the drain of the first MOS transistor M1, and the temperature The detection sub-circuit 320 and the first current source I1, the source of the first MOS transistor M1 is grounded, the first MOS transistor M1 is an N-channel MOS transistor, the first current source I1 generates a fixed current and flows through the first MOS transistor M1, Using the characteristics of the first MOS transistor M1, the temperature information of the LED driver chip is sampled; specifically, the gate and source voltages VGS of the first MOS transistor M1 represent the temperature information, and VGS is the voltage value input to the temperature detection sub-circuit 320 VSEN, which is equivalent to that the temperature sampling subcircuit 310 converts the current temperature value into a voltage value and outputs it to the temperature detection subcircuit 320.
  • the current temperature value is negatively correlated with VGS.
  • the corresponding VGS is lower, and the corresponding The lower the VSEN, on the contrary, when the temperature is lower, the corresponding VGS is higher, and the corresponding VSEN is higher, thereby realizing the sampling of the current temperature value of the LED driver chip.
  • the temperature detection sub-circuit 320 includes a first operational amplifier OP1, a second operational amplifier OP2, a second MOS transistor M2 and a second resistor R2; the non-inverting input terminal of the first operational amplifier OP1 is connected to the first operational amplifier OP1.
  • the inverting input terminal of the first operational amplifier OP1 is connected to one end of the second resistor R2 and the source of the second MOS transistor M2, the gate of the second MOS transistor M2 is connected to the output terminal of the first operational amplifier OP1, the first The drain of the two MOS transistor M2 is connected to the over-temperature adjustment circuit 100, the other end of the second resistor R2 is connected to the output end and the inverting input end of the second operational amplifier OP2, and the non-inverting input end of the second operational amplifier OP2 is connected to the temperature sampling sub The circuit 310 and the first current source I1; in this embodiment, the second MOS transistor M2 is an N-channel MOS transistor.
  • the over-temperature adjustment circuit 100 includes a third MOS transistor M3, a fourth MOS transistor M4, a fifth MOS transistor M5 and a sixth MOS transistor M6; the drain and gate of the third MOS transistor M3 and The gate of the fourth MOS transistor M4 is connected to the drain of the second MOS transistor M2, the source of the third MOS transistor M3 is connected to the source of the fourth MOS transistor M4; the drain of the fourth MOS transistor M4 is connected to the fifth MOS transistor The drain and gate of M5 and the gate of the sixth MOS transistor M6, the source of the fifth MOS transistor M5 is grounded, the source of the sixth MOS transistor M6 is grounded, and the drain of the sixth MOS transistor M6 is connected to the constant current circuit 200
  • the temperature-related current IOTP generated by the temperature detection sub-circuit 320 is corresponding to the mirror pull-down reference voltage of the third MOS transistor M3, the fourth MOS transistor M4, the fifth MOS transistor M5 and the sixth MOS transistor M6.
  • the mirrored temperature-related current is equivalent to the adjustment signal, which acts on the constant current circuit 200 to reduce the reference voltage input to the constant current circuit 200, and the reference voltage decreases , the constant current corresponding to the constant current circuit 200 is reduced, so that the power consumption falling on the LED driver chip is reduced, and the corresponding heat generation is reduced, so that the operating temperature of the LED driver chip falls within a reliable range, and the over-temperature of the LED driver chip is realized.
  • the adjustment signal acts on the constant current circuit 200 to reduce the reference voltage input to the constant current circuit 200, and the reference voltage decreases , the constant current corresponding to the constant current circuit 200 is reduced, so that the power consumption falling on the LED driver chip is reduced, and the corresponding heat generation is reduced, so that the operating temperature of the LED driver chip falls within a reliable range, and the over-temperature of the LED driver chip is realized.
  • the starter circuit 410 includes a third resistor R3, a ninth MOS transistor M9, a tenth MOS transistor M10, an eleventh MOS transistor M11 and a twelfth MOS transistor M12; One end is connected to the drain of the ninth MOS transistor M9 and the gate of the tenth MOS transistor M10, the other end of the third resistor R3 is connected to the power supply terminal, the source of the ninth MOS transistor M9, the source of the tenth MOS transistor M10 and the The sources of the eleven MOS transistors M11 are all grounded, the drain of the eleventh MOS transistor M11 is connected to the drain of the twelfth MOS transistor M12, the gate of the eleventh MOS transistor M11 and the gate of the ninth MOS transistor M9, The drain of the tenth MOS transistor M10 is connected to the gate of the twelfth MOS transistor M12 and the zero-temperature current sub-circuit 420, and the source of the twel
  • the starter sub-circuit 410 When the starter sub-circuit 410 is powered on, during the power supply voltage rising stage, the tenth MOS transistor M10 is turned on and pulls down a startup current. It is disconnected, thereby enabling the zero-temperature current sub-circuit 420 to be activated, so as to provide a reference voltage for the constant current circuit 200 subsequently.
  • the zero-temperature current sub-circuit 420 includes a thirteenth MOS transistor M13, a fourteenth MOS transistor M14, a fifteenth MOS transistor M15, a sixteenth MOS transistor M16, and a fourth resistor R4;
  • the source of the three MOS transistors M13 and the source of the fourteenth MOS transistor M14 are both connected to the power supply terminal, and the drain of the thirteenth MOS transistor M13 is connected to the drain and gate of the fifteenth MOS transistor M15 and the sixteenth MOS transistor
  • the gate of M16, the gate of the thirteenth MOS transistor M13 and the gate of the fourteenth MOS transistor M14 are all connected to the drain of the fourteenth MOS transistor M14, the gate of the twelfth MOS transistor M12 and the sixteenth MOS transistor
  • the drain of the transistor M16, the drain of the fourteenth MOS transistor M14 and the drain of the sixteenth MOS transistor M16 are also connected to the zero temperature voltage sub-circuit 430; the source of the sixteenth MO
  • the zero-temperature voltage sub-circuit 430 in this embodiment includes a seventeenth MOS transistor M17 and a fifth resistor R5, and the gate of the seventeenth MOS transistor is connected to the drain of the fourteenth MOS transistor M14 and the sixteenth MOS transistor M16.
  • the drain of the seventeenth MOS transistor M17 is connected to the power supply terminal, the drain of the seventeenth MOS transistor M17 is connected to one end of the fifth resistor R5 and the constant current circuit 200, and the other end of the fifth resistor R5 is grounded; this implementation
  • the seventeenth MOS transistor M17 is a P-channel MOS transistor, and the zero-temperature current of the zero-temperature current sub-circuit 420 is output to the gate of the seventeenth MOS transistor M17 through the drain of the seventeenth MOS transistor M17.
  • the mirror image of the seven MOS transistor M17 flows through the fifth resistor R5, thereby obtaining a zero-temperature reference voltage.
  • the second trimming sub-circuit 440 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, an eighteenth MOS transistor M18, a nineteenth MOS transistor M19, a second Ten MOS tube M20, the first fuse FUSE1, the second fuse FUSE2 and the third fuse FUSE3, one end of the sixth resistor R6, one end of the seventh resistor R7 and one end of the eighth resistor R8 are all connected to electricity, and the other end of the sixth resistor R6 is connected to electricity.
  • One end is connected to the gate of the twentieth MOS transistor M20 and one end of the first fuse FUSE1, the other end of the seventh resistor R7 is connected to the gate of the nineteenth MOS transistor M19 and one end of the second fuse FUSE2, and the other end of the eighth resistor R8 is connected.
  • One end is connected to the gate of the eighteenth MOS tube M18 and one end of the third fuse FUSE3, the other end of the first fuse FUSE1, the other end of the second fuse FUSE2 and the other end of the third fuse FUSE3 are all grounded, and the eighteenth MOS tube is connected to the ground.
  • the source and drain of M18, the source and drain of the nineteenth MOS transistor M19, and the source and drain of the twentieth MOS transistor M20 are all connected to the fifth resistor R5, and the corresponding fifth resistor R5 is equivalent to a plurality of The resistance is obtained in series; when the first fuse FUSE1, the second fuse FUSE2 and the third fuse FUSE3 are not blown, they are connected to the ground, and the eighteenth MOS tube M18, the nineteenth MOS tube M19 and the twentieth MOS tube M20 are all off On, the resistors R01, R02 and RO3 can be short-circuited respectively, thereby reducing the resistance value of the fifth resistor R5, so by controlling whether the first fuse FUSE1, the second fuse FUSE2 and the third fuse FUSE3 are blown, the value of R5 can be adjusted, Therefore, the magnitude of the reference voltage is adjusted; of course, in other embodiments, the circuit structure of the second trimming sub-circuit 440 with the same function can also be selected, which is not limited by the present invention.
  • the circuit structures of the first trimming sub-circuit 330 and the second trimming sub-circuit 440 in this embodiment are the same, so the circuit structure of the first trimming sub-circuit 330 will not be described in detail; since the N-type MOS transistor is seriously affected by the process, different The LED driver chips corresponding to different reference voltages VREF1, and the first trimming sub-circuit 330 is set to trim the voltage value of the reference voltage VREF1, so that the value VOTP of VSEN-VREF1 is consistent.
  • the value of VOTP at normal temperature and the negative temperature coefficient of VGS of the second MOS transistor M2
  • VOTP 180mV at room temperature of 25°C
  • the VGS of the second MOS transistor M2 drops by 1.5mV for every 1°C increase in the temperature of the LED driver chip.
  • VOTP 0mV.
  • the constant current circuit 200 includes a third operational amplifier OP3, a twenty-first MOS transistor M21 and a ninth resistor R9; the non-inverting input end of the third operational amplifier OP3 is connected to one end of the fifth resistor R5, the first The drain of the seventeenth MOS transistor M17 and the drain of the sixth MOS transistor M6, the inverting input end of the third operational amplifier OP3 is connected to one end of the ninth resistor R9 and the source of the twenty-first MOS transistor M21, the ninth resistor The other end of R9 is grounded, and the drain of the twenty-first MOS tube M21 is connected to the output end of the LED light string; in this embodiment, after the second MOS tube M2 is turned on, a temperature-related current is generated and then passed through the temperature adjustment circuit 100, the current value corresponding to the reference voltage is pulled down to reduce the voltage value of the reference voltage.
  • the VREF voltage is smaller; the reference voltage VREF is output to the constant current circuit 200, thus according to the temperature
  • the temperature sampling sub-circuit 310 includes a first resistor R1, and one end of the first resistor R1 is connected to the temperature detection sub-circuit 320 and the first current source I1, and the first The other end of the resistor R1 is grounded; the difference from the first embodiment is that the temperature sampling sub-circuit 310 in this embodiment adopts a resistor, and at the same time, a non-BJT device is sampled to realize the sampling of temperature information. Specifically, there is the sampling temperature information of the upper end voltage VSEN of the first resistor R1.
  • the first resistor R1 is a negative temperature coefficient resistor. The higher the temperature, the lower the VSEN.
  • the over-temperature adjustment circuit 100 includes a seventh MOS transistor M7 and an eighth MOS transistor M8; the drain, gate and eighth MOS transistor of the seventh MOS transistor M7
  • the gate of the transistor M8 is connected to the drain of the second MOS transistor M2
  • the source of the seventh MOS transistor M7 is connected to the source of the eighth MOS transistor M8, and the source of the eighth MOS transistor M8 is connected to the constant current circuit 200
  • the constant current circuit 200 further includes a tenth resistor R10, one end of the tenth resistor R10 is connected to the source of the eighth MOS transistor M8, and the other end of the tenth resistor R10 is connected to the first
  • the other end of the nine resistors R9 and the source of the twenty-first MOS transistor M21 when the current temperature value of the LED driver chip is too high, generates a temperature-related current IOTP through the seventh MOS and the eighth MOS transistor M8 After mirroring,
  • the temperature sampling sub-circuit 310 includes a second voltage source U2, one end of the second voltage source U2 is connected to the non-inverting input end of the second operational amplifier OP1, and the first The other end of the two voltage sources U2 is grounded; in this embodiment, the temperature detection sub-circuit 320 also includes an eleventh resistor R11 and a second current source I2, and the non-inverting input end of the first operational amplifier OP1 is connected to the second current source U2 and the second current source I2.
  • the second voltage source U2 provides the reference voltage VREF1 for the second operational amplifier OP2, and VSEN is positively correlated with temperature, and the temperature of the LED driving chip increases as the temperature increases.
  • the present invention also provides an LED driving circuit for eliminating the photoelectric effect of COB packaging. Since the LED driving circuit for eliminating the photoelectric effect of COB packaging has been introduced in detail above, it will not be described in detail here.
  • the LED drive circuit and drive chip provided by the present invention for eliminating the photoelectric effect of COB package
  • the LED drive circuit is connected with the LED light string, and includes an over-temperature adjustment circuit, a constant current circuit and a temperature detection circuit without a BJT device;
  • the detection circuit is connected with the over-temperature adjustment circuit for detecting the current temperature value, and outputs an over-temperature detection signal to the over-temperature adjustment circuit when the current temperature value is greater than the preset value;
  • the over-temperature adjustment circuit is connected with the constant current circuit for The over-temperature detection signal outputs the adjustment signal to the constant current circuit;
  • the constant current circuit is used to adjust the current flowing through the LED light string according to the adjustment signal; the utility model effectively avoids the photoelectric effect by setting the temperature detection circuit without the BJT device.
  • the influence of the LED driver chip solves the problem of abnormal operation of the constant current circuit caused by the photoelectric effect of the LED lighting COB package.

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Abstract

本实用新型公开了消除COB封装光电效应的LED驱动电路及驱动芯片，LED驱动电路与LED灯串连接，包括过温调节电路、恒流电路和未设置BJT器件的温度检测电路；温度检测电路与过温调节电路连接，用于检测当前温度值，并在当前温度值大于预设值时输出过温检测信号至过温调节电路；过温调节电路与恒流电路连接，用于根据过温检测信号输出调节信号至恒流电路；恒流电路用于根据调节信号调节流经LED灯串的电流；本实用新型通过设置未设置BJT器件的温度检测电路，从而有效避开光电效应对LED驱动芯片的影响，解决LED照明COB封装因光电效应造成恒流电路工作异常的问题。

Description

消除COB封装光电效应的LED驱动电路及驱动芯片 技术领域
本实用新型涉及LED照明技术领域，特别涉及消除COB封装光电效应的LED驱动电路及驱动芯片。
背景技术
现有LED照明COB封装方案，因采用LED灯珠与LED驱动芯片的裸芯片合封，LED灯珠为发光器件，LED驱动芯片驱动LED灯珠发光。当LED灯珠发光时，裸芯片受LED灯珠激发的光子影响，发生光电效应。该效应破坏LED驱动芯片中的恒流电路，使流过LED灯串的恒流电流异常。
LED驱动芯片电路通常由电压基准电路、过温调节电路、恒流电路等基础电路构成。经典成熟的电路中，过温调节电路内含BJT(双极结型晶体管：Bipolar Junction Transistor的简写，又称为半导体三极管器件)器件，利用BJT器件的BE结电压检测芯片的温度。而当BJT器件受光电效应影响会使其BE结电压降低，导致过温保护误判，从而引起恒流电路工作异常。
因而现有技术还有待改进和提高。
实用新型内容
鉴于上述现有技术的不足之处，本实用新型的目的在于提供的消除COB封装光电效应的LED驱动电路及驱动芯片，能够有效解决因LED灯珠与LED驱动芯片经COB封装后，LED驱动芯片设置有BJT器件而受光电效应影响致使LED驱动芯片中恒流电路工作异常的问题。
为了达到上述目的，本实用新型采取了以下技术方案：
一种消除COB封装光电效应的LED驱动电路，其与LED灯串连接，包括过温调节电路、恒流电路和未设置BJT器件的温度检测电路；温度检测电路与过温调节电路连 接，用于检测当前温度值，并在当前温度值大于预设值时输出过温检测信号至过温调节电路；过温调节电路与恒流电路连接，用于根据过温检测信号输出调节信号至恒流电路；恒流电路用于根据调节信号调节流经LED灯串的电流。
消除COB封装光电效应的LED驱动电路，还包括基准电压电路，基准电压电路与恒流电路连接，用于为恒流电路提供基准电压。
消除COB封装光电效应的LED驱动电路中，温度检测电路包括温度采样子电路、温度检测子电路和第一修调子电路；温度采样子电路与温度检测子电路连接，用于检测当前温度值并将当前温度值转换为电压值输出至温度检测子电路；温度检测子电路与过温调节电路连接，用于根据电压值和参考电压检测出当前温度值大于预设值时输出过温检测信号至过温调节电路；第一修调子电路与温度检测子电路连接，用于调节参考电压的电压值。
消除COB封装光电效应的LED驱动电路中，基准电压电路包括启动子电路、零温电流子电路、零温电压子电路和第二修调子电路；启动子电路连接零温电流子电路，用于为零温电流子电路提供启动电流；零温电流子电路与零温电压子电路连接，用于根据启动电流启动后输出零温电流至零温电压子电路；零温电压子电路与恒流电路连接，用于根据零温电流输出基准电压至恒流电路；第二修调子电路与零温电压子电路连接，用于调节基准电压的电压值。
消除COB封装光电效应的LED驱动电路中，温度采样子电路包括第一MOS管，第一MOS管的栅极连接第一MOS管的漏极、温度检测子电路和第一电流源，第一MOS管的源极接地。
消除COB封装光电效应的LED驱动电路中，温度采样子电路包括第一电阻，第一电阻的一端连接温度检测子电路和第一电流源，第一电阻的另一端接地。
消除COB封装光电效应的LED驱动电路中，温度检测子电路包括第一运算放大器、第二运算放大器、第二MOS管和第二电阻；第一运算放大器的正相输入端连接第一电压源，第一运算放大器的反相输入端连接第二电阻的一端和第二MOS管的源极，第二MOS管的栅极连接第一运算放大器的输出端，第二MOS管的漏极连接过温调节电路， 第二电阻的另一端连接第二运算放大器的输出端和反相输入端，第二运算放大器的正相输入端连接温度采样子电路和第一电流源。
消除COB封装光电效应的LED驱动电路中，过温调节电路包括第三MOS管、第四MOS管、第五MOS管和第六MOS管；第三MOS管的漏极和栅极以及第四MOS管的栅极均连接第二MOS管的漏极，第三MOS管的源极连接第四MOS管的源极；第四MOS管的漏极连接第五MOS管的漏极、栅极和第六MOS管的栅极，第五MOS管的源极接地，第六MOS管的源极接地，第六MOS管的漏极连接恒流电路。
消除COB封装光电效应的LED驱动电路中，过温调节电路包括第七MOS管、第八MOS管和第三电阻；第七MOS管的漏极、栅极和第八MOS管的栅极均连接第二MOS管的漏极，第七MOS管的源极连接第八MOS管的源极，第八MOS管的源极连接第三电阻的一端，第三电阻的另一端连接恒流电路。
一种消除COB封装光电效应的LED驱动芯片，包括上述的消除COB封装光电效应的LED驱动电路。
相较于现有技术，本实用新型提供的消除COB封装光电效应的LED驱动电路及驱动芯片，LED驱动电路与LED灯串连接，包括过温调节电路、恒流电路和未设置BJT器件的温度检测电路；温度检测电路与过温调节电路连接，用于检测当前温度值，并在当前温度值大于预设值时输出过温检测信号至过温调节电路；过温调节电路与恒流电路连接，用于根据过温检测信号输出调节信号至恒流电路；恒流电路用于根据调节信号调节流经LED灯串的电流；本实用新型通过设置未设置BJT器件的温度检测电路，从而有效避开光电效应对LED驱动芯片的影响，解决LED照明COB封装因光电效应造成恒流电路工作异常的问题。
附图说明
图1为本实用新型提供的消除COB封装光电效应的LED驱动电路的结构框图；
图2为本实用新型提供的消除COB封装光电效应的LED驱动电路中第一实施例的电路原理图；
图3为本实用新型提供的消除COB封装光电效应的LED驱动电路中启动子电路、零温电流子电路和零温电压子电路的电路原理图；
图4为本实用新型提供的消除COB封装光电效应的LED驱动电路中第二修调子电路的电路原理图；
图5为本实用新型提供的消除COB封装光电效应的LED驱动电路中第二实施例的电路原理图；
图6为本实用新型提供的消除COB封装光电效应的LED驱动电路中第三实施例的电路原理图；
图7为本实用新型提供的消除COB封装光电效应的LED驱动电路中第四实施例的电路原理图。
具体实施方式
本实用新型的目的在于提供消除COB封装光电效应的LED驱动电路及驱动芯片，能够有效解决因LED灯珠与LED驱动芯片经COB封装后，LED驱动芯片设置有BJT器件而受光电效应影响致使LED驱动芯片恒流电路工作异常的问题。
为使本实用新型的目的、技术方案及效果更加清楚、明确，以下参照附图并举实施例对本实用新型进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本实用新型，并不用于限定本实用新型。
请参阅图1，本实用新型提供的消除COB封装光电效应的LED驱动芯片中包括消除COB封装光电效应的LED驱动电路，该LED驱动电路与LED驱动芯片外部的LED灯串连接，具体来说，本实施例中LED驱动芯片和LED灯珠是通过COB封装集成在一起的；其中，消除COB封装光电效应的LED驱动电路包括过温调节电路100、恒流电路200和未设置BJT器件的温度检测电路300；温度检测电路300与过温调节电路100连接，用于检测当前温度值，并在当前温度值大于预设值时输出过温检测信号至过温调节电路100；过温调节电路100与恒流电路200连接，用于根据过温检测信号输出调节信号至恒流电路200；恒流电路200用于根据调节信号调节流经LED灯串的电流；本实 用新型通过设置未设置BJT器件的温度检测电路300，对LED驱动芯片的当前温度值进行检测，相当于不以BJT器件的BE结电压检测LED驱动芯片的温度，从而避开光电效应对LED驱动芯片的影响，解决LED照明COB封装因光电效应造成恒流电路工作异常的问题。
进一步地，消除COB封装光电效应的LED驱动电路还包括基准电压电路400，基准电压电路400与恒流电路200连接，用于为恒流电路200提供基准电压，那么恒流电路200可根据基准电压设置流经LED灯串的电流，使得LED灯串正常工作。
进一步地，请一并参阅图2，温度检测电路300包括温度采样子电路310、温度检测子电路320和第一修调子电路330；温度采样子电路310与温度检测子电路320连接，用于将检测当前温度值并将当前温度值转换为电压值输出至温度检测子电路320；温度检测子电路320与过温调节电路100连接，用于根据电压值和参考电压检测出当前温度值大于预设值时输出过温检测信号至过温调节电路100；第一修调子电路330与温度检测子电路320连接，用于调节参考电压的电压值；本实施例中温度采样子电路310、温度检测子电路320和第一修调子电路330中均未设置BJT器件。
具体地，本实施例中直接由温度采样子电路310将LED驱动芯片的温度值转换为电压值，且该电压值与温度值呈负相关，当温度值越大则该电压值越小；之后，当温度检测子电路320检测到该电压值小于参考电压时，表明当前温度值大于预设值，也即LED驱动芯片过温，当前温度值超过过温点温度，则输出一过温检测信号至过温调节电路100，过温调节电路100根据该过温检测信号输出与LED驱动芯片的当前温度值相关的调节信号作用于恒流电路200，以调节恒流电路200的电流输出，也即调节流经LED灯串的电流；由于温度采样子电路310、温度检测子电路320和第一修调子电路330中均未设置BJT器件，采用非BJT器件采样LED驱动芯片的温度信息，而非BJT器件受工艺制程影响较大，通过设置第一修调子电路330保证温度检测电路300对温度检测的准确性。
进一步地，请参阅图3，基准电压电路400包括启动子电路410、零温电流子电路420、零温电压子电路430和第二修调子电路440；启动子电路410连接零温电流子电路 420，用于为零温电流子电路420提供启动电流；零温电流子电路420与零温电压子电路430连接，用于根据启动电流启动后输出零温电流至零温电压子电路430；零温电压子电路430与恒流电路200连接，用于根据零温电流输出基准电压至恒流电路200；第二修调子电路440与零温电压子电路430连接，用于调节基准电压的电压值；基准电压电路400接电后，当电源电压上升时，输出一启动电流至零温电流子电路420；当零温电流子电路420启动之后，启动子电路410会关闭，之后由零温电流子电路420为零温电压子电路430提供零温电流，零温电压子电路430根据零温电流输出基准电压至恒流电路，由此实现基准电压的输出；而第二修调子电路440的设置，可以实现对基准电压的电压值的调节，以便于满足后续恒流电路200的恒流设置。
进一步地，请继续参阅图2，本实用新型的第一实施例中，温度采样子电路310包括第一MOS管M1，第一MOS管M1的栅极连接第一MOS管M1的漏极、温度检测子电路320和第一电流源I1，第一MOS管M1的源极接地，第一MOS管M1为N沟道MOS管，第一电流源I1产生固定的电流流经第一MOS管M1，利用第一MOS管M1的特性，采样LED驱动芯片的温度信息；具体地，第一MOS管M1的栅极和源极电压VGS表征温度信息，且VGS为输入至温度检测子电路320的电压值VSEN，由此相当于所述温度采样子电路310将当前温度值转换为电压值后输出给温度检测子电路320，当前温度值与VGS负相关，当温度越高则对应VGS越低，对应的VSEN越低，反之，当温度越低则对应VGS越高，对应的VSEN越高，进而实现对LED驱动芯片的当前温度值的采样。
进一步地，本实施例中，温度检测子电路320包括第一运算放大器OP1、第二运算放大器OP2、第二MOS管M2和第二电阻R2；第一运算放大器OP1的正相输入端连接第一电压源U1，第一运算放大器OP1的反相输入端连接第二电阻R2的一端和第二MOS管M2的源极，第二MOS管M2的栅极连接第一运算放大器OP1的输出端，第二MOS管M2的漏极连接过温调节电路100，第二电阻R2的另一端连接第二运算放大器OP2的输出端和反相输入端，第二运算放大器OP2的正相输入端连接温度采样子电路310和第一电流源I1；本实施例中，第二MOS管M2为N沟道MOS管。
第二运算放大器OP2的正相输入端的电压对应为VSEN，第一运算放大器OP1的正相输入端输入的电压为参考电压VREF1；当LED驱动芯片的当前温度值大于预设值时，则第一运算放大器OP1的正相输入端输入的参考电压VREF1大于VSEN，第二MOS管M2导通，产生与温度相关的电流IOTP＝(VREF1-VSEN)/R2，也即过温检测信号，其中R2为第二电阻R2的阻值；当LED驱动芯片的当前温度值未达到预设值时，第一运算放大器OP1的正相输入端的参考电压VREF1小于VSEN，则第二MOS管M2断开，IOTP＝0；由此在当前温度至大于预设值时，则温度检测子电路320为会产生一个与产生与温度相关的电流至过温调节电路100，以便于后续调节LED灯串的电流。
进一步地，本实施例中，过温调节电路100包括第三MOS管M3、第四MOS管M4、第五MOS管M5和第六MOS管M6；第三MOS管M3的漏极和栅极以及第四MOS管M4的栅极均连接第二MOS管M2的漏极，第三MOS管M3的源极连接第四MOS管M4的源极；第四MOS管M4的漏极连接第五MOS管M5的漏极、栅极和第六MOS管M6的栅极，第五MOS管M5的源极接地，第六MOS管M6的源极接地，第六MOS管M6的漏极连接恒流电路200；本实施例中，温度检测子电路320产生的与温度相关的电流IOTP经第三MOS管M3、第四MOS管M4、第五MOS管M5和第六MOS管M6的镜像下拉基准电压对应的电流，进而降低基准电压；其中，本实施例中经镜像后的与温度相关的电流相当于调节信号，作用于恒流电路200使得输入至恒流电路200的基准电压降低，而基准电压减小，则恒流电路200对应的恒流电流减小，使得落在LED驱动芯片上的功耗降低，那么对应的发热减少，使得LED驱动芯片工作温度落在可靠区间，实现LED驱动芯片的过温保护。
进一步地，请继续参阅图3，启动子电路410包括第三电阻R3、第九MOS管M9、第十MOS管M10、第十一MOS管M11和第十二MOS管M12；第三电阻R3的一端连接第九MOS管M9的漏极和第十MOS管M10的栅极，第三电阻R3的另一端连接电源端，第九MOS管M9的源极、第十MOS管M10的源极和第十一MOS管M11的源极均接地，第十一MOS管M11的漏极连接第十二MOS管M12的漏极、第十一MOS管M11的栅极和第九MOS管M9的栅极，第十MOS管M10的漏极连接第十二MOS 管M12的栅极和零温电流子电路420，第十二MOS管M12的源极连接电源端；本实施例中，第九MOS管M9和第十一MOS管M11为N沟道MOS管，第十MOS管M10和第十二MOS管M12为P沟道MOS管。
当启动子电路410接电后，电源电压上升阶段内，此时第十MOS管M10导通后下拉一启动电流，之后零温电流子电路420根据该启动电流启动后，则第十MOS管M10断开，由此实现启动零温电流子电路420，以便于后续为恒流电路200提供基准电压。
进一步地，本实施例中，零温电流子电路420包括第十三MOS管M13、第十四MOS管M14、第十五MOS管M15、第十六MOS管M16和第四电阻R4；第十三MOS管M13的源极和第十四MOS管M14的源极均连接电源端，第十三MOS管M13的漏极连接第十五MOS管M15的漏极、栅极和第十六MOS管M16的栅极，第十三MOS管M13的栅极和第十四MOS管M14的栅极均连接第十四MOS管M14的漏极、第十二MOS管M12的栅极和第十六MOS管M16的漏极，第十四MOS管M14的漏极和第十六MOS管M16的漏极还连接零温电压子电路430；第十六MOS管M16的源极连接第四电阻R4的一端，第四电阻R4的另一端接地，第十五MOS管M15的源极接地；本实施例中第十三MOS管M13和第十四MOS管M14均为P沟道MOS管，第十五MOS管M15和第十六MOS管M16均为N沟道MOS管。
当零温电流子电路420启动之后输出一零温电流，该零温电流IBIS＝(VGS15-VGS16)/R4，其中，VGS15为第十五MOS管M15的栅极和源极电压，VGS16为第十六MOS管M16的栅极和源极电压，R4为第四电阻R4的阻值。
进一步地，本实施例中零温电压子电路430包括第十七MOS管M17和第五电阻R5，十七MOS管的栅极连接第十四MOS管M14的漏极和第十六MOS管M16的漏极，第十七MOS管M17的源极连接电源端，第十七MOS管M17的漏极连接第五电阻R5的一端和恒流电路200，第五电阻R5的另一端接地；本实施例中第十七MOS管M17为P沟道MOS管，零温电流子电路420的零温电流经第十七MOS管M17的漏极输出给第十七MOS管M17的栅极，经第十七MOS管M17镜像后流过第五电阻R5，进而得到零温的基准电压。
进一步地，请参阅图4，本实施例中第二修调子电路440包括第六电阻R6、第七电阻R7、第八电阻R8、第十八MOS管M18、第十九MOS管M19、第二十MOS管M20、第一保险丝FUSE1、第二保险丝FUSE2和第三保险丝FUSE3，第六电阻R6的一端、第七电阻R7的一端和第八电阻R8的一端均接电，第六电阻R6的另一端连接第二十MOS管M20的栅极和第一保险丝FUSE1的一端，第七电阻R7的另一端连接第十九MOS管M19的栅极和第二保险丝FUSE2的一端，第八电阻R8的另一端连接第十八MOS管M18的栅极和第三保险丝FUSE3的一端，第一保险丝FUSE1的另一端、第二保险丝FUSE2的另一端和第三保险丝FUSE3的另一端均接地，第十八MOS管M18的源极和漏极、第十九MOS管M19的源极和漏极以及第二十MOS管M20的源极和漏极均连接第五电阻R5，对应的第五电阻R5相当于多个电阻串联得到；当第一保险丝FUSE1、第二保险丝FUSE2和第三保险丝FUSE3未烧断之前，连通到地，第十八MOS管M18、第十九MOS管M19和第二十MOS管M20均断开，可分别短路电阻R01、R02和RO3，从而减小了第五电阻R5的阻值，故而通过控制第一保险丝FUSE1、第二保险丝FUSE2和第三保险丝FUSE3是否烧断，可调整R5值，从而调整基准电压的大小；当然在其他实施例中也可选择具有相同功能的第二修调子电路440的电路结构，本实用新型对此不做限。
其中，本实施例中第一修调子电路330和第二修调子电路440的电路结构相同，因此对第一修调子电路330的电路结构不做赘述；由于N型MOS管受工艺影响严重，不同的LED驱动芯片将对应不同的参考电压VREF1，通过设置第一修调子电路330修调参考电压VREF1的电压值，使得VSEN-VREF1的值VOTP一致。通过设计VOTP常温下的值、第二MOS管M2的VGS的负温系数，从而确定芯片的过温点温度。例如本实施例中设计，常温25℃条件下VOTP＝180mV，LED驱动芯片温度每升高1℃，第二MOS管M2的VGS下掉1.5mV，当LED驱动芯片温度达到145℃时，VOTP＝0mV。LED驱动芯片温度持续升高，产生一个与温度相关的电流IOTP，IOTP＝(VREF1-VSEN)/R1，以便于后续过温调节电路100根据该电流调节流经LED灯串的电流，实现过温保护。
进一步地，本实施例中恒流电路200包括第三运算放大器OP3、第二十一MOS管 M21和第九电阻R9；第三运算放大器OP3的正相输入端连接第五电阻R5的一端、第十七MOS管M17的漏极和第六MOS管M6的漏极，第三运算放大器OP3的反相输入端连接第九电阻R9的一端和第二十一MOS管M21的源极，第九电阻R9的另一端接地，第二十一MOS管M21的漏极连接LED灯串的输出端；本实施例中在第二MOS管M2导通后，产生一个与温度相关的电流后经过温调节电路100的镜像，下拉基准电压对应的电流值，来降低基准电压的电压值，当LED驱动芯片的温度越高，则VREF电压越小；该基准电压VREF输出给恒流电路200，由此根据温度检测电路300和过温调节电路100来设置基准电压VREF，调节LED灯串电流的输出，其中，ILED＝VREF/R9，R9为第九电阻R9的阻值，因此，基准电压VREF越低，则流经LED灯串电流越小，使得落在LED驱动芯片上的功耗降低，那么对应的发热减少，使得LED驱动芯片工作温度落在可靠区间，实现LED驱动芯片的过温保护。
进一步地，请参阅图5，本实用新型的第二实施例中，温度采样子电路310包括第一电阻R1，第一电阻R1的一端连接温度检测子电路320和第一电流源I1，第一电阻R1的另一端接地；与第一实施例不同的是，本实施例中温度采样子电路310采用的是电阻，同时采样的是非BJT器件实现对温度信息的采样。具体地，有第一电阻R1的上端电压VSEN采样温度信息，第一电阻R1为负温度系数电阻，温度越高，VSEN越低，当VSEN低于VREF1时，第二MOS管M2开启，产生与温度相关的电流IOTP＝(VREF1-VSEN)/R2，该电流经第三MOS管M3、第四MOS管M4、第五MOS管M5和第六MOS管M6形成的电流镜的镜像后，会下拉基准电压对应的电流，降低基准电压的电压值，基准电压减小，则恒流电流IOUT＝VREF/R10减小，落在LED驱动芯片上的功耗降低，LED驱动芯片发热减少，使芯片工作温度落在可靠区间。
进一步地，请参阅图6，本实用新型的第三实施中，过温调节电路100包括第七MOS管M7和第八MOS管M8；第七MOS管M7的漏极、栅极和第八MOS管M8的栅极均连接第二MOS管M2的漏极，第七MOS管M7的源极连接第八MOS管M8的源极，第八MOS管M8的源极连接所述恒流电路200；本实施例中所述恒流电路200还包括第十电阻R10，所述第十电阻R10的一端连接所述第八MOS管M8的源极，所 述第十电阻R10的另一端连接所述第九电阻R9的另一端和所述第二十一MOS管M21的源极，当LED驱动芯片的当前温度值过高时，产生一个与温度相关的电流IOTP经第七MOS、第八MOS管M8镜像后流经第十电阻R10，经镜像后的与温度相关的电流相当于调节信号，该调节信号输入恒流电路200，调节了恒流电路200中第九电阻R9上端的电压，从而来调节LED灯串的电流，此时ILED＝(VREF-IOTP*R10)/R9，IOTP＝(VREF1-VSEN)/R2，R9和R10分别为第九电阻R9和第十电阻R10的阻值，当过温之后，温度越高，VSEN越小，则IOPT越大，那么ILED越小，落在LED驱动芯片上的功耗降低，LED驱动芯片发热减少，使芯片工作温度落在可靠区间，由此实现过温保护。
进一步地，请参阅图7，本实用新型的第四实施例中，温度采样子电路310包括第二电压源U2，第二电压源U2的一端连接第二运算放大器OP1的正相输入端，第二电压源U2的另一端接地；本实施例中温度检测子电路320中还包括第十一电阻R11和第二电流源I2，第一运算放大器OP1的正相输入端连接第二电流源U2和第十一电阻R11的一端，第十一电阻R11的另一端接地；本实施例中由第二电压源U2为第二运算放大器OP2提供参考电压VREF1，VSEN与温度正相关，LED驱动芯片温度越高，则VSEN电压越大；当LED驱动芯片的当前温度值未大于预设值时，VREF1大于VSEN，此时第二MOS管关闭，IOTP＝0，当LED驱动芯片的当前温度值大于预设值时，则IOTP＝(VSEN-VREF1)/R2，该电流经后续过温调节电路100镜像后作用于恒流电路200，进而下拉基准电压对应的电流值，来降低基准电压的电压值，实现对LED驱动芯片的过温保护。
本实用新型还相应提供一种消除COB封装光电效应的LED驱动电路，由于上文已对消除COB封装光电效应的LED驱动电路进行了详细介绍，此处不再详述。
综上，本实用新型提供的消除COB封装光电效应的LED驱动电路及驱动芯片，LED驱动电路与LED灯串连接，包括过温调节电路、恒流电路和未设置BJT器件的温度检测电路；温度检测电路与过温调节电路连接，用于检测当前温度值，并在当前温度值大于预设值时输出过温检测信号至过温调节电路；过温调节电路与恒流电路连接，用于根 据过温检测信号输出调节信号至恒流电路；恒流电路用于根据调节信号调节流经LED灯串的电流；本实用新型通过设置未设置BJT器件的温度检测电路，从而有效避开光电效应对LED驱动芯片的影响，解决LED照明COB封装因光电效应造成恒流电路工作异常的问题。
可以理解的是，对本领域普通技术人员来说，可以根据本实用新型的技术方案及其实用新型构思加以等同替换或改变，而所有这些改变或替换都应属于本实用新型所附的权利要求的保护范围。

Claims (10)

  1. 一种消除COB封装光电效应的LED驱动电路，其与LED灯串连接，其特征在于，包括过温调节电路、恒流电路和未设置BJT器件的温度检测电路；所述温度检测电路与所述过温调节电路连接，用于检测当前温度值，并在当前温度值大于预设值时输出过温检测信号至所述过温调节电路；所述过温调节电路与所述恒流电路连接，用于根据所述过温检测信号输出调节信号至所述恒流电路；所述恒流电路用于根据所述调节信号调节流经所述LED灯串的电流。
  2. 根据权利要求1所述的消除COB封装光电效应的LED驱动电路，其特征在于，还包括基准电压电路，所述基准电压电路与所述恒流电路连接，用于为所述恒流电路提供基准电压。
  3. 根据权利要求1所述的消除COB封装光电效应的LED驱动电路，其特征在于，所述温度检测电路包括温度采样子电路、温度检测子电路和第一修调子电路；所述温度采样子电路与所述温度检测子电路连接，用于检测当前温度值并将当前温度值转换为电压值输出至所述温度检测子电路；所述温度检测子电路与所述过温调节电路连接，用于根据所述电压值和参考电压检测出当前温度值大于预设值时输出所述过温检测信号至所述过温调节电路；所述第一修调子电路与所述温度检测子电路连接，用于调节所述参考电压的电压值。
  4. 根据权利要求2所述的消除COB封装光电效应的LED驱动电路，其特征在于，所述基准电压电路包括启动子电路、零温电流子电路、零温电压子电路和第二修调子电路；所述启动子电路连接所述零温电流子电路，用于为所述零温电流子电路提供启动电流；所述零温电流子电路与所述零温电压子电路连接，用于根据所述启动电流启动后输出零温电流至所述零温电压子电路；所述零温电压子电路与所述恒流电路连接，用于根据所述零温电流输出基准电压至所述恒流电路；所述第二修调子电路与所述零温电压子电路连接，用于调节所述基准电压的电压值。
  5. 根据权利要求3所述的消除COB封装光电效应的LED驱动电路，其特征在于，所述温度采样子电路包括第一MOS管，所述第一MOS管的栅极连接所述第一MOS管的漏极、所述温度检测子电路和第一电流源，所述第一MOS管的源极接地。
  6. 根据权利要求3所述的消除COB封装光电效应的LED驱动电路，其特征在于，所述温度采样子电路包括第一电阻，所述第一电阻的一端连接所述温度检测子电路和第一电流源，所述第一电阻的另一端接地。
  7. 根据权利要求5或6任意一项所述的消除COB封装光电效应的LED驱动电路，其特征在于，所述温度检测子电路包括第一运算放大器、第二运算放大器、第二MOS管和第二电阻；所述第一运算放大器的正相输入端连接第一电压源，所述第一运算放大器的反相输入端连接所述第二电阻的一端和第二MOS管的源极，所述第二MOS管的栅极连接所述第一运算放大器的输出端，所述第二MOS管的漏极连接所述过温调节电路，所述第二电阻的另一端连接所述第二运算放大器的输出端和反相输入端，所述第二运算放大器的正相输入端连接所述温度采样子电路和第一电流源。
  8. 根据权利要求7所述的消除COB封装光电效应的LED驱动电路，其特征在于，所述过温调节电路包括第三MOS管、第四MOS管、第五MOS管和第六MOS管；所述第三MOS管的漏极和栅极以及所述第四MOS管的栅极均连接所述第二MOS管的漏极，所述第三MOS管的源极连接所述第四MOS管的源极；所述第四MOS管的漏极连接所述第五MOS管的漏极、栅极和所述第六MOS管的栅极，所述第五MOS管的源极接地，所述第六MOS管的源极接地，所述第六MOS管的漏极连接所述恒流电路。
  9. 根据权利要求7所述的消除COB封装光电效应的LED驱动电路，其特征在于，所述过温调节电路包括第七MOS管和第八MOS管；所述第七MOS管的漏极、栅极和所述第八MOS管的栅极均连接所述第二MOS管的漏极，所述第七MOS管的源极连接所述第八MOS管的源极，所述第八MOS管的源极连接所述恒流电路。
  10. 一种消除COB封装光电效应的LED驱动芯片，其特征在于，包括权利要求1-9任意一项所述的消除COB封装光电效应的LED驱动电路。
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