CN213522468U - LED drive circuit and drive chip for eliminating COB packaging photoelectric effect - Google Patents

LED drive circuit and drive chip for eliminating COB packaging photoelectric effect Download PDF

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Publication number
CN213522468U
CN213522468U CN202022345389.7U CN202022345389U CN213522468U CN 213522468 U CN213522468 U CN 213522468U CN 202022345389 U CN202022345389 U CN 202022345389U CN 213522468 U CN213522468 U CN 213522468U
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circuit
temperature
sub
current
mos transistor
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叶羽安
邓迅升
王文攀
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Shenzhen Sendis Semiconductor Co Ltd
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Shenzhen Sendis Semiconductor Co Ltd
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Priority to PCT/CN2021/108980 priority patent/WO2022083203A1/en
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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

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Abstract

The utility model discloses a LED drive circuit and a drive chip for eliminating COB packaging photoelectric effect, wherein the LED drive circuit is connected with an LED lamp string and comprises an over-temperature adjusting 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 used for detecting the current temperature value and outputting an over-temperature detection signal to the over-temperature regulation circuit when the current temperature value is greater than a preset value; the over-temperature regulating circuit is connected with the constant current circuit and used for outputting a regulating signal to the constant current circuit according to the over-temperature detection signal; the constant current circuit is used for regulating the current flowing through the LED lamp string according to the regulating signal; the utility model discloses a temperature detection circuit that the setting does not set up the BJT device to effectively keep away the photoelectric effect and reply LED driver chip's influence, solve the encapsulation of LED illumination COB and cause the unusual problem of constant current circuit work because of the photoelectric effect.

Description

LED drive circuit and drive chip for eliminating COB packaging photoelectric effect
Technical Field
The utility model relates to a LED lighting technology field, in particular to eliminate LED drive circuit and driver chip of COB encapsulation photoelectric effect.
Background
According to the conventional LED lighting COB packaging scheme, the LED lamp beads and bare chips of the LED driving chips are sealed in a combined mode, the LED lamp beads are light-emitting devices, and the LED driving chips drive the LED lamp beads to emit light. When the LED lamp beads emit light, the bare chips are affected by photons excited by the LED lamp beads, and a photoelectric effect occurs. This effect destroys the constant current circuit in the LED driver chip, causing the constant current flowing through the LED string to be abnormal.
The LED driving chip circuit is generally composed of basic circuits such as a voltage reference circuit, an over-temperature adjustment circuit, and a constant current circuit. In a classical mature circuit, the over-temperature regulating circuit contains a BJT (Bipolar Junction Transistor, abbreviated as a semiconductor triode device) device, and the BE Junction voltage of the BJT device is used to detect the temperature of the chip. When the BJT device is influenced by the photoelectric effect, the BE junction voltage of the BJT device is reduced, and over-temperature protection misjudgment is caused, so that the constant current circuit works abnormally.
Thus, the prior art has yet to be improved and enhanced.
SUMMERY OF THE UTILITY MODEL
In view of the weak point of above-mentioned prior art, the utility model aims to provide an eliminate LED drive circuit and driver chip of COB encapsulation photoelectric effect can effectively solve because of LED lamp pearl and LED driver chip through COB encapsulation back, LED driver chip is provided with the BJT device and receives the photoelectric effect influence to cause the unusual problem of constant current circuit work among the LED driver chip.
In order to achieve the purpose, the utility model adopts the following technical proposal:
an LED drive circuit for eliminating COB packaging photoelectric effect is connected with an LED lamp string and comprises an over-temperature regulating 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 used for detecting the current temperature value and outputting an over-temperature detection signal to the over-temperature regulation circuit when the current temperature value is greater than a preset value; the over-temperature regulating circuit is connected with the constant current circuit and used for outputting a regulating signal to the constant current circuit according to the over-temperature detection signal; the constant current circuit is used for regulating the current flowing through the LED lamp string according to the regulating signal.
The LED driving circuit for eliminating the COB packaging photoelectric effect further comprises a reference voltage circuit, wherein the reference voltage circuit is connected with the constant current circuit and used for providing reference voltage for the constant current circuit.
In the LED drive circuit for eliminating the COB packaging photoelectric effect, the temperature detection circuit comprises 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 and used for detecting the current temperature value and converting the current temperature value into a voltage value to be output to the temperature detection sub-circuit; the temperature detection sub-circuit is connected with the over-temperature regulating circuit and used for outputting an over-temperature detection signal to the over-temperature regulating circuit when detecting that the current temperature value is greater than a preset value according to the voltage value and the reference voltage; the first trimming sub-circuit is connected with the temperature detection sub-circuit and is used for adjusting the voltage value of the reference voltage.
In the LED drive circuit for eliminating the COB packaging photoelectric effect, a reference voltage circuit comprises a promoter circuit, a zero-temperature current sub-circuit, a zero-temperature voltage sub-circuit and a second trimming sub-circuit; the promoter circuit is connected with the zero-temperature current sub-circuit and is used for providing starting current for the zero-temperature current sub-circuit; the zero-temperature current sub-circuit is connected with the zero-temperature voltage sub-circuit and is used for outputting a zero-temperature current to the zero-temperature voltage sub-circuit after being started according to the starting current; the zero-temperature voltage sub-circuit is connected with the constant current circuit and used for outputting reference voltage to the constant current circuit according to the zero-temperature current; the second trimming sub-circuit is connected with the zero-temperature voltage sub-circuit and is used for adjusting the voltage value of the reference voltage.
In the LED drive circuit for eliminating the COB packaging photoelectric effect, the temperature sampling sub-circuit comprises a first MOS tube, the grid electrode of the first MOS tube is connected with the drain electrode of the first MOS tube, the temperature detection sub-circuit and the first current source, and the source electrode of the first MOS tube is grounded.
In the LED drive circuit for eliminating the COB packaging photoelectric effect, the temperature sampling sub-circuit comprises a first resistor, one end of the first resistor is connected with the temperature detection sub-circuit and the first current source, and the other end of the first resistor is grounded.
In the LED drive circuit for eliminating the COB packaging photoelectric effect, the temperature detection sub-circuit comprises a first operational amplifier, a second MOS tube and a second resistor; the positive phase input end of the first operational amplifier is connected with a first voltage source, the negative phase input end of the first operational amplifier is connected with one end of a second resistor and the source electrode of a second MOS tube, the grid electrode of the second MOS tube is connected with the output end of the first operational amplifier, the drain electrode of the second MOS tube is connected with an over-temperature regulating circuit, the other end of the second resistor is connected with the output end and the negative phase input end of the second operational amplifier, and the positive phase input end of the second operational amplifier is connected with a temperature sampling sub-circuit and a first current source.
In the LED driving circuit for eliminating the COB packaging photoelectric effect, the over-temperature regulating circuit comprises a third MOS tube, a fourth MOS tube, a fifth MOS tube and a sixth MOS tube; the drain electrode and the grid electrode of the third MOS tube and the grid electrode of the fourth MOS tube are connected with the drain electrode of the second MOS tube, and the source electrode of the third MOS tube is connected with the source electrode of the fourth MOS tube; the drain electrode of the fourth MOS tube is connected with the drain electrode and the grid electrode of the fifth MOS tube and the grid electrode of the sixth MOS tube, the source electrode of the fifth MOS tube is grounded, the source electrode of the sixth MOS tube is grounded, and the drain electrode of the sixth MOS tube is connected with the constant current circuit.
In the LED driving circuit for eliminating the COB packaging photoelectric effect, the over-temperature regulating circuit comprises a seventh MOS tube, an eighth MOS tube and a third resistor; the drain electrode of the seventh MOS tube, the grid electrode of the seventh MOS tube and the grid electrode of the eighth MOS tube are all connected with the drain electrode of the second MOS tube, the source electrode of the seventh MOS tube is connected with the source electrode of the eighth MOS tube, the source electrode of the eighth MOS tube is connected with one end of a third resistor, and the other end of the third resistor is connected with a constant current circuit.
The utility model provides an eliminate LED driver chip of COB encapsulation photoelectric effect, includes foretell LED drive circuit of eliminating COB encapsulation photoelectric effect.
Compared with the prior art, the LED drive circuit and the drive chip for eliminating the COB packaging photoelectric effect provided by the utility model have the advantages that the LED drive circuit is connected with the LED lamp string and comprises an over-temperature adjusting 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 used for detecting the current temperature value and outputting an over-temperature detection signal to the over-temperature regulation circuit when the current temperature value is greater than a preset value; the over-temperature regulating circuit is connected with the constant current circuit and used for outputting a regulating signal to the constant current circuit according to the over-temperature detection signal; the constant current circuit is used for regulating the current flowing through the LED lamp string according to the regulating signal; the utility model discloses a temperature detection circuit that the setting does not set up the BJT device to effectively keep away the photoelectric effect and reply LED driver chip's influence, solve the encapsulation of LED illumination COB and cause the unusual problem of constant current circuit work because of the photoelectric effect.
Drawings
Fig. 1 is a block diagram of an LED driving circuit for eliminating the COB package photoelectric effect provided by the present invention;
fig. 2 is a schematic circuit diagram of a first embodiment of an LED driving circuit for eliminating the COB package photoelectric effect provided by the present invention;
fig. 3 is a schematic circuit diagram of a sub-circuit of a zero-temperature current and a sub-circuit of a zero-temperature voltage in an LED driving circuit for eliminating the photoelectric effect of COB package;
fig. 4 is a schematic circuit diagram of a second trimming sub-circuit in the LED driving circuit for eliminating the COB package photoelectric effect provided by the present invention;
fig. 5 is a schematic circuit diagram of a second embodiment of an LED driving circuit for eliminating the COB package photoelectric effect provided by the present invention;
fig. 6 is a schematic circuit diagram of a third embodiment of an LED driving circuit for eliminating the COB package photoelectric effect provided by the present invention;
fig. 7 is the utility model provides an eliminate the circuit schematic diagram of fourth embodiment in the LED drive circuit of COB encapsulation photoelectric effect.
Detailed Description
An object of the utility model is to provide an eliminate COB encapsulation photoelectric effect's LED drive circuit and driver chip, can effectively solve because of LED lamp pearl and LED driver chip through the COB encapsulation back, LED driver chip is provided with the BJT device and causes the unusual problem of LED driver chip constant current circuit work by photoelectric effect influence.
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the following description of the present invention will refer to the accompanying drawings and illustrate embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.
Referring to fig. 1, the LED driving chip for eliminating the COB package photoelectric effect provided by the present invention includes an LED driving circuit for eliminating the COB package photoelectric effect, the LED driving circuit is connected to an LED light string outside the LED driving chip, specifically, the LED driving chip and the LED light bead are integrated together by COB package in this embodiment; the LED driving circuit for eliminating the COB packaging photoelectric effect comprises an over-temperature adjusting circuit 100, a constant current circuit 200 and a temperature detection circuit 300 without a BJT device; the temperature detection circuit 300 is connected to the over-temperature adjustment circuit 100, and is configured to detect a current temperature value and output an over-temperature detection signal to the over-temperature adjustment circuit 100 when the current temperature value is greater than a preset value; the over-temperature regulating circuit 100 is connected with the constant current circuit 200 and is used for outputting a regulating signal to the constant current circuit 200 according to the over-temperature detection signal; the constant current circuit 200 is used for regulating the current flowing through the LED lamp string according to the regulating signal; the utility model discloses a temperature detection circuit 300 that does not set up the BJT device is set up, detects the current temperature value of LED driver chip, is equivalent to the BE junction voltage that does not use the BJT device and detects the temperature of LED driver chip to avoid the influence of photoelectric effect reply LED driver chip, solve the problem that LED illumination COB encapsulation caused constant current circuit work anomaly because of photoelectric effect.
Further, the LED driving circuit for eliminating the COB package photoelectric effect further includes a reference voltage circuit 400, the reference voltage circuit 400 is connected to the constant current circuit 200 and is configured to provide a reference voltage for the constant current circuit 200, and then the constant current circuit 200 may set a current flowing through the LED light string according to the reference voltage, so that the LED light string normally operates.
Further, referring to fig. 2, the temperature detecting circuit 300 includes a temperature sampling sub-circuit 310, a temperature detecting sub-circuit 320, and a first trimming sub-circuit 330; the temperature sampling sub-circuit 310 is connected to the temperature detection sub-circuit 320, and is configured to detect a current temperature value, convert the current temperature value into a voltage value, and output the voltage value to the temperature detection sub-circuit 320; the temperature detection sub-circuit 320 is connected to the over-temperature adjustment circuit 100, and is configured to output an over-temperature detection signal to the over-temperature adjustment circuit 100 when detecting that the current temperature value is greater than the preset value according to the voltage value and the reference voltage; the first trimming sub-circuit 330 is connected to the temperature detecting sub-circuit 320 for adjusting the voltage value of the reference voltage; in this embodiment, none of the temperature sampling sub-circuit 310, the temperature detection sub-circuit 320, and the first trimming sub-circuit 330 has a BJT device.
Specifically, in the present embodiment, the temperature sampling sub-circuit 310 directly converts the temperature value of the LED driving chip into a voltage value, and the voltage value is negatively correlated with the temperature value, and the voltage value is smaller when the temperature value is larger; then, when the temperature detection sub-circuit 320 detects that the voltage value is smaller than the reference voltage, it indicates that the current temperature value is greater than the preset value, that is, the LED driving chip is over-temperature, and when the current temperature value exceeds the over-temperature point temperature, an over-temperature detection signal is output to the over-temperature adjusting circuit 100, and the over-temperature adjusting circuit 100 outputs an adjusting signal related to the current temperature value of the LED driving chip according to the over-temperature detection signal to act on the constant current circuit 200, so as to adjust the current output of the constant current circuit 200, that is, adjust the current flowing through the LED lamp string; since no BJT device is disposed in the temperature sampling sub-circuit 310, the temperature detecting sub-circuit 320, and the first trimming sub-circuit 330, the non-BJT device is used to sample the temperature information of the LED driving chip, and the non-BJT device is greatly affected by the process, and the first trimming sub-circuit 330 is disposed to ensure the accuracy of the temperature detecting circuit 300 in detecting the temperature.
Further, referring to fig. 3, the reference voltage circuit 400 includes a 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 starting sub-circuit 410 is connected with the zero-temperature current sub-circuit 420 and is used for providing starting current for 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 configured to output a zero-temperature current to the zero-temperature voltage sub-circuit 430 after being started according to the starting current; the zero-temperature voltage sub-circuit 430 is connected with the constant current circuit 200 and is used 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, and is configured to adjust a voltage value of the reference voltage; after the reference voltage circuit 400 is powered on, when the power voltage rises, the reference voltage circuit outputs a starting current to the zero-temperature current sub-circuit 420; when the zero-temperature current sub-circuit 420 is started, the sub-circuit 410 is closed, then the zero-temperature current sub-circuit 420 provides zero-temperature current for the zero-temperature voltage sub-circuit 430, and the zero-temperature voltage sub-circuit 430 outputs reference voltage to the constant current circuit according to the zero-temperature current, so that the output of the reference voltage is realized; the second trimming sub-circuit 440 is configured to adjust the voltage value of the reference voltage, so as to satisfy the constant current setting of the subsequent constant current circuit 200.
Further, please continue to refer to fig. 2, in the first embodiment of the present invention, the temperature sampling sub-circuit 310 includes a first MOS transistor M1, a gate of the first MOS transistor M1 is connected to a drain of the first MOS transistor M1, the temperature detection sub-circuit 320 and a first current source I1, a 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 to flow through the first MOS transistor M1, and the temperature information of the LED driving chip is sampled by using the characteristic of the first MOS transistor M1; specifically, the gate and source voltages VGS of the first MOS transistor M1 represent temperature information, and VGS is a voltage value VSEN input to the temperature detection sub-circuit 320, so that the temperature sampling sub-circuit 310 converts a current temperature value into a voltage value and outputs the voltage value to the temperature detection sub-circuit 320, the current temperature value is negatively related to VGS, the higher the temperature is, the lower the corresponding VGS is, and the lower the corresponding VSEN is, otherwise, the lower the temperature is, the higher the corresponding VGS is, the higher the corresponding VSEN is, and further sampling of the current temperature value of the LED driving chip is achieved.
Further, in the present embodiment, 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; a non-inverting input terminal of the first operational amplifier OP1 is connected to a first voltage source U1, an inverting input terminal of the first operational amplifier OP1 is connected to one end of a second resistor R2 and a source of a second MOS transistor M2, a gate of the second MOS transistor M2 is connected to an output terminal of the first operational amplifier OP1, a drain of the second MOS transistor M2 is connected to the over-temperature regulating circuit 100, the other end of the second resistor R2 is connected to an output terminal and an inverting input terminal of a second operational amplifier OP2, and a non-inverting input terminal of the second operational amplifier OP2 is connected to the temperature sampling sub-circuit 310 and the first current source I1; in this embodiment, the second MOS transistor M2 is an N-channel MOS transistor.
The voltage at the non-inverting input terminal of the second operational amplifier OP2 is VSEN, and the voltage at the non-inverting input terminal of the first operational amplifier OP1 is the reference voltage VREF 1; when the current temperature value of the LED driving chip is greater than the preset value, the reference voltage VREF1 input by the non-inverting input terminal of the first operational amplifier OP1 is greater than VSEN, the second MOS transistor M2 is turned on, and a temperature-related current iot ═ VREF1-VSEN)/R2, that is, an over-temperature detection signal is generated, where R2 is a resistance value of the second resistor R2; when the current temperature value of the LED driving chip does not reach the preset value, the reference voltage VREF1 at the non-inverting input terminal of the first operational amplifier OP1 is less than VSEN, the second MOS transistor M2 is turned off, and iot is 0; therefore, when the current temperature is higher than the predetermined value, the temperature detection sub-circuit 320 generates a current related to the temperature to the over-temperature adjustment circuit 100, so as to adjust the current of the LED string.
Further, in the present embodiment, the over-temperature regulating 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 the gate of the third MOS transistor M3 and the gate of the fourth MOS transistor M4 are both connected to the drain of the second MOS transistor M2, and 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 drain and the gate of the fifth MOS transistor 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; in this embodiment, the temperature-related current IOTP generated by the temperature detection sub-circuit 320 passes through the currents corresponding to the mirror pull-down reference voltages of the third MOS transistor M3, the fourth MOS transistor M4, the fifth MOS transistor M5 and the sixth MOS transistor M6, so as to reduce the reference voltage; in this embodiment, the mirrored temperature-related current is equivalent to an adjustment signal, and acts on the constant current circuit 200 to reduce the reference voltage input to the constant current circuit 200, and when the reference voltage is reduced, the constant current corresponding to the constant current circuit 200 is reduced, so that the power consumption falling on the LED driving chip is reduced, and the corresponding heat generation is reduced, so that the operating temperature of the LED driving chip falls in a reliable interval, and the over-temperature protection of the LED driving chip is realized.
Further, with reference to fig. 3, the sub-start 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 of a third resistor R3 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 a power supply terminal, the source of the ninth MOS transistor M9, the source of the tenth MOS transistor M10 and the source of the eleventh MOS transistor 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 twelfth MOS transistor M12 is connected to the power supply terminal; in this embodiment, the ninth MOS transistor M9 and the eleventh MOS transistor M11 are N-channel MOS transistors, and the tenth MOS transistor M10 and the twelfth MOS transistor M12 are P-channel MOS transistors.
When the sub-circuit 410 is powered on, the tenth MOS transistor M10 is turned on to pull down a start current in the power voltage rising stage, and then the sub-circuit 420 is started according to the start current, and the tenth MOS transistor M10 is turned off, so as to start the sub-circuit 420, and provide a reference voltage for the constant current circuit 200 subsequently.
Further, in the present embodiment, 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; a source electrode of the thirteenth MOS transistor M13 and a source electrode of the fourteenth MOS transistor M14 are both connected to a power supply terminal, a drain electrode of the thirteenth MOS transistor M13 is connected to a drain electrode and a gate electrode of the fifteenth MOS transistor M15 and a gate electrode of the sixteenth MOS transistor M16, a gate electrode of the thirteenth MOS transistor M13 and a gate electrode of the fourteenth MOS transistor M14 are both connected to a drain electrode of the fourteenth MOS transistor M14, a gate electrode of the twelfth MOS transistor M12 and a drain electrode of the sixteenth MOS transistor M16, and a drain electrode of the fourteenth MOS transistor M14 and a drain electrode of the sixteenth MOS transistor M16 are also connected to the zero-temperature voltage sub-circuit 430; the source of the sixteenth MOS transistor M16 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, and the source of the fifteenth MOS transistor M15 is grounded; in this embodiment, the thirteenth MOS transistor M13 and the fourteenth MOS transistor M14 are both P-channel MOS transistors, and the fifteenth MOS transistor M15 and the sixteenth MOS transistor M16 are both N-channel MOS transistors.
When the zero-temperature current sub-circuit 420 is activated, a zero-temperature current is output, where the zero-temperature current IBIS is (VGS15-VGS16)/R4, where VGS15 is a gate and source voltage of the fifteenth MOS transistor M15, VGS16 is a gate and source voltage of the sixteenth MOS transistor M16, and R4 is a resistance of the fourth resistor R4.
Further, in the present embodiment, the zero-temperature voltage sub-circuit 430 includes a seventeenth MOS transistor M17 and a fifth resistor R5, a gate of the seventeenth MOS transistor is connected to the drain of the fourteenth MOS transistor M14 and the drain of the sixteenth MOS transistor M16, a source of the seventeenth MOS transistor M17 is connected to a power supply terminal, a 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; in this embodiment, the seventeenth MOS transistor M17 is a P-channel MOS transistor, 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, and flows through the fifth resistor R5 after being mirrored by the seventeenth MOS transistor M17, so as to obtain the zero-temperature reference voltage.
Further, referring to fig. 4, in the present embodiment, 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 twentieth MOS transistor M20, a first FUSE1, a second FUSE2 and a third 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 power, the other end of the sixth resistor R6 is connected to the gate of the twentieth MOS transistor M20 and one end of the first FUSE1, the other end of the seventh resistor R7 is connected to the gate of the nineteenth MOS transistor M5739 and one end of the second FUSE2, the other end of the eighth resistor R8 is connected to the gate of the eighteenth MOS transistor M18 and one end of the third FUSE3, the other end of the first FUSE 68628, the second FUSE1 and the other end of the second FUSE 36867 and the other end of the second FUSE 36874 are all connected to ground, and the drain of the third FUSE 18, The source and the drain of the nineteenth MOS transistor M19 and the source and the drain of the twentieth MOS transistor M20 are both connected with a fifth resistor R5, and the corresponding fifth resistor R5 is obtained by connecting a plurality of resistors in series; when the first FUSE FUSE1, the second FUSE FUSE2 and the third FUSE FUSE3 are not blown, the eighteenth MOS transistor M18, the nineteenth MOS transistor M19 and the twentieth MOS transistor M20 are all disconnected and short-circuit resistors R01, R02 and RO3 can be respectively realized, so that the resistance value of the fifth resistor R5 is reduced, and the R5 value can be adjusted by controlling whether the first FUSE FUSE1, the second FUSE FUSE2 and the third FUSE FUSE3 are blown or not, so that the magnitude of the reference voltage can be adjusted; of course, the circuit structure of the second trimming sub-circuit 440 having the same function may be selected in other embodiments, which is not limited by the present invention.
In this embodiment, the circuit structures of the first trimming sub-circuit 330 and the second trimming sub-circuit 440 are the same, and therefore the circuit structure of the first trimming sub-circuit 330 is not described in detail; because the N-type MOS transistor is seriously affected by the process, different LED driver chips correspond to different reference voltages VREF1, and the voltage value of the reference voltage VREF1 is modified by setting the first modification sub-circuit 330, so that the values VOTP of VSEN-VREF1 are consistent. The over-temperature point temperature of the chip is determined by designing the value of VOTP at normal temperature and the negative temperature coefficient of VGS of the second MOS tube M2. For example, in the design of this embodiment, the VOTP is 180mV at 25 ℃ and 1.5mV drops under VGS of the second MOS transistor M2 for every 1 ℃ rise of the temperature of the LED driving chip, and when the temperature of the LED driving chip reaches 145 ℃, the VOTP is 0 mV. The temperature of the LED driving chip is continuously increased to generate a temperature-dependent current iot (VREF1-VSEN)/R1, so that the subsequent over-temperature adjusting circuit 100 adjusts the current flowing through the LED string according to the current to realize over-temperature protection.
Further, the constant current circuit 200 in this embodiment includes a third operational amplifier OP3, a twenty-first MOS transistor M21, and a ninth resistor R9; the positive phase input end of the third operational amplifier OP3 is connected with one end of the fifth resistor R5, the drain electrode of the seventeenth MOS transistor M17 and the drain electrode of the sixth MOS transistor M6, the negative phase input end of the third operational amplifier OP3 is connected with one end of the ninth resistor R9 and the source electrode of the twenty-first MOS transistor M21, the other end of the ninth resistor R9 is grounded, and the drain electrode of the twenty-first MOS transistor M21 is connected with the output end of the LED lamp string; in this embodiment, after the second MOS transistor M2 is turned on, a current related to temperature is generated, and then the current value corresponding to the reference voltage is pulled down through the mirror image of the temperature adjustment circuit 100 to reduce the voltage value of the reference voltage, and when the temperature of the LED driving chip is higher, the VREF voltage is smaller; the reference voltage VREF is output to the constant current circuit 200, so that the reference voltage VREF is set according to the temperature detection circuit 300 and the over-temperature adjustment circuit 100, and the output of the LED string current is adjusted, wherein ILED is VREF/R9, and R9 is the resistance of the ninth resistor R9, so that the lower the reference voltage VREF is, the smaller the LED string current flows through, the power consumption on the LED driver chip is reduced, the corresponding heat generation is reduced, the working temperature of the LED driver chip falls in a reliable interval, and the over-temperature protection of the LED driver chip is realized.
Further, referring to fig. 5, in the second embodiment of the present invention, the temperature sampling sub-circuit 310 includes a first resistor R1, one end of the first resistor R1 is connected to the temperature detection sub-circuit 320 and the first current source I1, and the other end of the first resistor R1 is grounded; unlike the first embodiment, in the present embodiment, the temperature sampling sub-circuit 310 employs a resistor, and the sampling is performed by a non-BJT device to sample the temperature information. Specifically, the upper end voltage VSEN of the first resistor R1 samples temperature information, the first resistor R1 is a negative temperature coefficient resistor, the VSEN is lower as the temperature is higher, when the VSEN is lower than VREF1, the second MOS transistor M2 is turned on, a current iot (VREF1-VSEN)/R2 related to the temperature is generated, and after the current passes through a mirror image of a current mirror formed by the third MOS transistor M3, the fourth MOS transistor M4, the fifth MOS transistor M5 and the sixth MOS transistor M6, a current corresponding to a reference voltage is pulled down, the voltage value of the reference voltage is reduced, the constant current IOUT/VREF/R10 is reduced, power consumption on the LED driving chip is reduced, and heat generation of the LED driving chip is reduced, so that the operating temperature of the chip falls in a reliable interval.
Further, referring to fig. 6, in a third embodiment of the present invention, the over-temperature regulating circuit 100 includes a seventh MOS transistor M7 and an eighth MOS transistor M8; the drain and the gate of the seventh MOS transistor M7 and the gate of the eighth MOS transistor M8 are all 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; in this embodiment, 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, the other end of the tenth resistor R10 is connected to the other end of the ninth resistor R9 and the source of the twenty-first MOS transistor M21, when the current temperature value of the LED driving chip is too high, a temperature-related current IOTP is generated and mirrored by the seventh MOS and the eighth MOS transistor M8, and then flows through the tenth resistor R10, the mirrored temperature-related current corresponds to an adjustment signal, the adjustment signal is input to the constant current circuit 200, and the voltage at the upper end of the ninth resistor R9 in the constant current circuit 200 is adjusted, so as to adjust the current of the LED light string, at this time, ILED (VREF-iot R10)/R9, iovref 1-VSEN)/R2, R9 and R10 are the resistance values of the ninth resistor R9 and the tenth resistor R10, respectively, and after the temperature is too high, the higher the temperature is, the smaller VSEN is, the larger IOPT is, the smaller ILED is, the power consumption on the LED driving chip is reduced, the heating of the LED driving chip is reduced, the working temperature of the chip is in a reliable interval, and therefore over-temperature protection is achieved.
Further, referring to fig. 7, in a fourth embodiment of the present invention, 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 terminal of the second operational amplifier OP1, and the other end of the second voltage source U2 is grounded; the temperature detection sub-circuit 320 in this embodiment further includes an eleventh resistor R11 and a second current source I2, a non-inverting input terminal of the first operational amplifier OP1 is connected to one end of the second current source U2 and one end of the eleventh resistor R11, and the other end of the eleventh resistor R11 is grounded; in this embodiment, the second voltage source U2 provides the second operational amplifier OP2 with the reference voltage VREF1, VSEN is positively correlated to the temperature, and the higher the temperature of the LED driving chip is, the higher the voltage of VSEN is; when the current temperature value of the LED driver chip is not greater than the preset value, VREF1 is greater than VSEN, the second MOS transistor is turned off, iot is 0, and when the current temperature value of the LED driver chip is greater than the preset value, iot is (VSEN-VREF1)/R2, and the current is mirrored by the subsequent over-temperature adjusting circuit 100 and then acts on the constant current circuit 200, so as to pull down the current value corresponding to the reference voltage, thereby reducing the voltage value of the reference voltage and realizing the over-temperature protection of the LED driver chip.
The utility model discloses still the corresponding LED drive circuit who provides an elimination COB encapsulation photoelectric effect because the above has carried out detailed introduction to the LED drive circuit who eliminates COB encapsulation photoelectric effect, and here is no longer detailed.
To sum up, the utility model provides a eliminate COB encapsulation photoelectric effect's LED drive circuit and driver chip, LED drive circuit and LED lamp cluster are connected, including excess temperature regulating circuit, constant current circuit and not setting up the temperature detection circuit of BJT device; the temperature detection circuit is connected with the over-temperature regulation circuit and used for detecting the current temperature value and outputting an over-temperature detection signal to the over-temperature regulation circuit when the current temperature value is greater than a preset value; the over-temperature regulating circuit is connected with the constant current circuit and used for outputting a regulating signal to the constant current circuit according to the over-temperature detection signal; the constant current circuit is used for regulating the current flowing through the LED lamp string according to the regulating signal; the utility model discloses a temperature detection circuit that the setting does not set up the BJT device to effectively keep away the photoelectric effect and reply LED driver chip's influence, solve the encapsulation of LED illumination COB and cause the unusual problem of constant current circuit work because of the photoelectric effect.
It should be understood that equivalent alterations and modifications can be made by those skilled in the art according to the technical solution of the present invention and the inventive concept thereof, and all such alterations and modifications should fall within the scope of the appended claims.

Claims (10)

1. An LED drive circuit for eliminating COB packaging photoelectric effect is connected with an LED lamp string and is characterized by comprising an over-temperature regulating circuit, a constant current circuit and a temperature detection circuit without a BJT device; the temperature detection circuit is connected with the over-temperature regulating circuit and used for detecting a current temperature value and outputting an over-temperature detection signal to the over-temperature regulating circuit when the current temperature value is greater than a preset value; the over-temperature regulating circuit is connected with the constant current circuit and used for outputting a regulating signal to the constant current circuit according to the over-temperature detection signal; the constant current circuit is used for adjusting the current flowing through the LED lamp string according to the adjusting signal.
2. The LED driving circuit for eliminating the photoelectric effect of COB packages according to claim 1, further comprising a reference voltage circuit, wherein the reference voltage circuit is connected with the constant current circuit and is used for providing a reference voltage for the constant current circuit.
3. The LED driving circuit for eliminating the COB packaging photoelectric effect according to claim 1, wherein the temperature detection circuit comprises 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 and is used for detecting the current temperature value, converting the current temperature value into a voltage value and outputting the voltage value to the temperature detection sub-circuit; the temperature detection sub-circuit is connected with the over-temperature regulating circuit and is used for outputting an over-temperature detection signal to the over-temperature regulating circuit when detecting that the current temperature value is greater than a preset value according to the voltage value and the reference voltage; the first trimming sub-circuit is connected with the temperature detection sub-circuit and is used for adjusting the voltage value of the reference voltage.
4. The LED driving circuit for eliminating the photoelectric effect of COB packages according to claim 2, wherein the reference voltage circuit comprises a promoter circuit, a zero-temperature current sub-circuit, a zero-temperature voltage sub-circuit and a second trimming sub-circuit; the starting circuit is connected with the zero-temperature current sub-circuit and is used for providing starting current for the zero-temperature current sub-circuit; the zero-temperature current sub-circuit is connected with the zero-temperature voltage sub-circuit and is used for outputting a zero-temperature current to the zero-temperature voltage sub-circuit after being started according to the starting current; the zero-temperature voltage sub-circuit is connected with the constant current circuit and used for outputting reference voltage to the constant current circuit according to the zero-temperature current; and the second trimming sub-circuit is connected with the zero-temperature voltage sub-circuit and is used for adjusting the voltage value of the reference voltage.
5. The LED driving circuit for eliminating the COB package photoelectric effect according to claim 3, wherein the temperature sampling sub-circuit comprises a first MOS transistor, a gate of the first MOS transistor is connected to a drain of the first MOS transistor, the temperature detection sub-circuit and a first current source, and a source of the first MOS transistor is grounded.
6. The LED driving circuit for eliminating the COB packaging photoelectric effect as claimed in claim 3, wherein the temperature sampling sub-circuit comprises a first resistor, one end of the first resistor is connected to the temperature detection sub-circuit and a first current source, and the other end of the first resistor is grounded.
7. The LED driving circuit for eliminating the photoelectric effect of COB packages according to any one of claims 5 or 6, wherein the temperature detection sub-circuit comprises a first operational amplifier, a second MOS transistor and a second resistor; the positive phase input end of the first operational amplifier is connected with a first voltage source, the negative phase input end of the first operational amplifier is connected with one end of a second resistor and the source electrode of a second MOS tube, the grid electrode of the second MOS tube is connected with the output end of the first operational amplifier, the drain electrode of the second MOS tube is connected with the over-temperature regulating circuit, the other end of the second resistor is connected with the output end and the negative phase input end of the second operational amplifier, and the positive phase input end of the second operational amplifier is connected with the temperature sampling sub-circuit and the first current source.
8. The LED driving circuit for eliminating the COB package photoelectric effect according to claim 7, wherein the over-temperature regulating circuit comprises a third MOS transistor, a fourth MOS transistor, a fifth MOS transistor and a sixth MOS transistor; the drain electrode and the grid electrode of the third MOS tube and the grid electrode of the fourth MOS tube are connected with the drain electrode of the second MOS tube, and the source electrode of the third MOS tube is connected with the source electrode of the fourth MOS tube; the drain electrode of the fourth MOS tube is connected with the drain electrode and the grid electrode of the fifth MOS tube and the grid electrode of the sixth MOS tube, the source electrode of the fifth MOS tube is grounded, the source electrode of the sixth MOS tube is grounded, and the drain electrode of the sixth MOS tube is connected with the constant current circuit.
9. The LED driving circuit for eliminating the COB packaging photoelectric effect according to claim 7, wherein the over-temperature regulating circuit comprises a seventh MOS transistor and an eighth MOS transistor; the drain electrode and the grid electrode of the seventh MOS tube and the grid electrode of the eighth MOS tube are connected with the drain electrode of the second MOS tube, the source electrode of the seventh MOS tube is connected with the source electrode of the eighth MOS tube, and the source electrode of the eighth MOS tube is connected with the constant current circuit.
10. An LED driving chip for eliminating COB package photoelectric effect, comprising the LED driving circuit for eliminating COB package photoelectric effect of any one of claims 1 to 9.
CN202022345389.7U 2020-10-20 2020-10-20 LED drive circuit and drive chip for eliminating COB packaging photoelectric effect Active CN213522468U (en)

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CN103281836B (en) * 2013-06-06 2015-04-01 东莞博用电子科技有限公司 Chip over-temperature protection circuit applied to alternative current LED drive system
CN103826361B (en) * 2014-01-14 2016-11-23 深圳市晶台股份有限公司 A kind of LED COB controllable temperature system
CN208953151U (en) * 2018-10-18 2019-06-07 杭州士兰微电子股份有限公司 Excess temperature detection device
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CN110944432A (en) * 2019-12-16 2020-03-31 华帝股份有限公司 LED lamp constant current output circuit with over-temperature detection function and over-temperature detection method
CN111142603B (en) * 2019-12-18 2021-11-16 芯创智（北京）微电子有限公司 Circuit and device for detecting reference voltage bjt tube temperature saving
CN213522468U (en) * 2020-10-20 2021-06-22 深圳市晟碟半导体有限公司 LED drive circuit and drive chip for eliminating COB packaging photoelectric effect

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022083203A1 (en) * 2020-10-20 2022-04-28 深圳市晟碟半导体有限公司 Led drive circuit and led drive chip for eliminating cob encapsulation photoelectric effect

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