CN212519507U - Over-temperature protection circuit, LED driving power supply, driving board card and display device - Google Patents
Over-temperature protection circuit, LED driving power supply, driving board card and display device Download PDFInfo
- Publication number
- CN212519507U CN212519507U CN202020985419.8U CN202020985419U CN212519507U CN 212519507 U CN212519507 U CN 212519507U CN 202020985419 U CN202020985419 U CN 202020985419U CN 212519507 U CN212519507 U CN 212519507U
- Authority
- CN
- China
- Prior art keywords
- circuit
- over
- power supply
- thermistor
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Abstract
The utility model relates to an excess temperature protection circuit and LED drive power supply. The over-temperature protection circuit of the utility model comprises a switch control chip, a feedback control circuit, a switch circuit and at least one over-temperature detection circuit; the feedback control circuit comprises a light emitting diode and an optical signal converter, wherein the current input end of the light emitting diode is connected with the power supply, and the current input end of the optical signal converter is connected with the feedback input end of the switch control chip; the switch circuit comprises a first end, a second end and a controlled end, wherein the first end is connected with the current output end of the light-emitting diode; each over-temperature detection circuit comprises a power supply end, a grounding end, a voltage output end, a thermistor and a resistor, wherein the thermistor and the resistor are connected in series and then connected between the power supply end and the grounding end, the voltage output end is connected between the thermistor and the resistor, and the voltage output end is also connected with a controlled end of the switch circuit; the utility model discloses an excess temperature protection circuit has realized the quick overload of LED drive power supply and excess temperature protection.
Description
Technical Field
The utility model relates to an electronic circuit's technical field especially relates to an excess temperature protection circuit, LED drive power supply, drive integrated circuit board and display device.
Background
In recent years, LEDs (Light Emitting diodes) are widely used as a green and energy-saving Light source in lighting systems and in the field of home appliances for backlight display of display devices. In a traditional LED dimming mode, constant current is mainly output through a constant current driving circuit to control the brightness of an LED.
In a traditional LED driving power circuit, when power output is overloaded, the temperature of a transformer can rise, so that overcurrent protection needs to be carried out on the output of the transformer, but the traditional overcurrent protection circuit has the problems of more devices, high cost, large PCB occupation area and the like.
SUMMERY OF THE UTILITY MODEL
Based on this, the utility model provides an excess temperature protection circuit and constant current drive circuit, the device is few, and is with low costs, and PCB area occupied is little, has realized the quick overload of LED drive power supply and has crossed temperature protection.
In a first aspect, the utility model provides an excess temperature protection circuit is applied to LED drive power supply, include:
the control circuit comprises a switch control chip, a feedback control circuit, a switch circuit and at least one over-temperature detection circuit;
the switch control chip comprises a feedback input end;
the feedback control circuit comprises an optocoupler, the optocoupler comprises a light emitting diode and an optical signal converter, the current input end of the light emitting diode is connected with a power supply, the current input end of the optical signal converter is connected with the feedback input end of the switch control chip, and the current output end of the optical signal converter is grounded;
the switch circuit comprises a first end connected with the current output end of the light-emitting diode, a second end connected with the ground and a controlled end;
for each over-temperature detection circuit, the over-temperature detection circuit comprises a power supply end, a grounding end, a voltage output end, a thermistor and a resistor, wherein the thermistor and the resistor are connected in series and then are connected between the power supply end and the grounding end, the voltage output end is connected between the thermistor and the resistor, and the voltage output end is also connected with a controlled end of the switch circuit;
when the voltage of the controlled end of the switch circuit reaches the controlled voltage, the first end and the second end of the switch circuit are conducted, the current of the light-emitting diode is increased, the light signal converter is conducted in a saturated mode, the voltage of the feedback input end of the switch control chip is reduced, the switch control chip stops outputting the driving signal, and the LED driving power supply is turned off.
Optionally, the thermistor is a negative temperature coefficient thermistor, a first end of the thermistor is used for connecting the power supply end, a second end of the thermistor is connected with the first end of the resistor, and the second end of the resistor is used for connecting the ground end;
the resistance value of the resistor is configured to enable the voltage output by the voltage output end of the over-temperature detection circuit to be larger than or equal to the controlled voltage of the switch circuit when the resistance value of the thermistor is lower than a first set value.
Optionally, the thermistor is a positive temperature coefficient thermistor, a first end of the resistor is used for connecting the power supply end, a second end of the resistor is connected with the first end of the thermistor, and the second end of the thermistor is used for connecting the ground end;
the resistance value of the resistor is configured to enable the voltage output by the voltage output end of the over-temperature detection circuit to be larger than or equal to the controlled voltage of the switch circuit when the resistance value of the thermistor is higher than a second set value.
Optionally, the switching circuit includes a controllable precise voltage-stabilizing source, a cathode of the controllable precise voltage-stabilizing source is a first end of the switching circuit, an anode of the controllable precise voltage-stabilizing source is a second end of the switching circuit, and a reference end of the controllable precise voltage-stabilizing source is a controlled end of the switching circuit.
Optionally, the LED driving power supply includes a first constant current boosting unit for outputting the LED constant current driving power supply, where the first constant current boosting unit includes a first diode, and an output end of the first diode is provided with a first copper sheet;
the over-temperature detection circuit comprises a first over-temperature detection circuit, the first over-temperature detection circuit comprises a first thermistor and a first resistor which are connected in series, and the first thermistor is attached to the first copper sheet.
Optionally, a power supply end of the first over-temperature detection circuit is used for being connected to an output end of the first constant current boosting unit.
Optionally, the constant current driving circuit includes a second constant current boosting unit for outputting a 12V chip driving power supply, the second constant current boosting unit includes a second diode, and an output end of the second diode is provided with a second copper sheet;
the over-temperature detection circuit comprises a second over-temperature detection circuit, the second over-temperature detection circuit comprises a second thermistor and a second resistor which are connected in series, and the second thermistor is attached to the second copper sheet.
Optionally, a power supply end of the second over-temperature detection circuit is used for being connected to an output end of the second constant current boosting unit.
Optionally, the constant current driving circuit includes a third constant current boosting unit for outputting 18V auxiliary power, the third constant current boosting unit includes a third diode, and an output end of the third diode is provided with a third copper sheet;
the over-temperature detection circuit comprises a third over-temperature detection circuit, the third over-temperature detection circuit comprises a third thermistor and a third resistor which are connected in series, and the third thermistor is attached to the third copper sheet.
Optionally, a power supply end of the third over-temperature detection circuit is used to be connected to an output end of the third constant current boosting unit.
Optionally, the over-temperature protection circuit further includes a locking circuit;
the locking circuit comprises a power supply end, a grounding end and a voltage stabilizing end, the grounding end of the locking circuit is connected with the first end of the switch circuit, the voltage stabilizing end of the locking circuit is connected with the controlled end of the switch circuit, and when the first end and the second end of the switch circuit are conducted, the voltage output by the voltage stabilizing end of the locking circuit is larger than or equal to the controlled voltage of the switch circuit.
Optionally, the locking circuit includes a PNP triode, a fourth resistor, and a fifth resistor;
the emitting electrode of the PNP triode is connected with the power supply end of the locking circuit, the base set of the PNP triode is connected with the power supply end of the locking circuit through the fourth resistor, the base set of the PNP triode is further connected with the grounding end of the locking circuit through the fifth resistor, and the collecting electrode of the PNP triode is connected to the voltage stabilizing end of the locking circuit.
In a second aspect, the present invention provides an LED driving power supply, which comprises a main power circuit, a constant current control circuit and an over-temperature protection circuit as described in the first aspect of the present invention;
the power supply main circuit is used for outputting a voltage signal to the constant current control circuit, and the constant current control circuit is used for converting the voltage signal into a constant current electrical signal;
the feedback control circuit is used for monitoring and adjusting the output voltage of the power main circuit in real time and outputting a feedback signal to the switch control chip, and the switch control chip controls the output of the power main circuit according to the feedback signal.
Third aspect, the utility model provides a drive integrated circuit board, include the utility model discloses the second aspect LED drive power supply.
In a fourth aspect, the utility model provides a display device, including the LED load with the utility model discloses the third aspect the drive integrated circuit board, the current input end of LED load with LED drive power supply's constant current control circuit's backlight current output end is connected.
The utility model discloses an excess temperature protection circuit, when LED drive power supply transships and generates heat, detect the situation of generating heat through thermistor to according to thermistor's characteristic, change excess temperature detection circuit's output voltage, thereby make switch circuit switch on, feedback control circuit draws down switch control chip's feedback voltage, makes switch control chip stop output control signal, thereby turn-offs LED drive power supply, the utility model discloses an excess temperature protection circuit device is few, and is with low costs, and PCB area occupied is little, has realized the quick overload of LED drive power supply and the excess temperature protection.
For better understanding and implementation, the technical solutions of the present invention are described in detail below with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of a circuit configuration of an LED driving power supply according to an example of the prior art;
fig. 2 is a schematic circuit diagram of an over-temperature protection circuit according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of an over-temperature detection circuit according to an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of an over-temperature protection circuit according to an embodiment of the present invention;
fig. 5 is a schematic circuit diagram of an over-temperature protection circuit according to an embodiment of the present invention;
fig. 6 is a schematic circuit diagram of an over-temperature protection circuit according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of an LED driving power supply according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a driving board card according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of a display device according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the relevant portions of the present invention are shown in the drawings.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, are not to be construed as limiting the present invention.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
In the following, several specific embodiments are given for describing the technical solution of the present application in detail. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.
Fig. 1 is a schematic circuit structure diagram of an LED driving power supply in an example of the prior art, and includes a main power supply circuit, a constant current control circuit, a feedback control circuit, and a primary side control circuit.
The power supply main circuit is configured to perform voltage level conversion and ac-dc conversion on a power supply input by the power supply input terminal Vbridge, and output a constant voltage, and in the example shown in fig. 1, the power supply main circuit includes three paths of output signals.
In the example shown in fig. 1, the constant current control circuit includes a plurality of constant current boost units, and is configured to convert three voltage signals output by the power main circuit into VBL for supplying power to the LED, and 18V and 12V voltages for supplying power to other components and the control chip, respectively. In other examples, the number of the constant current boosting units may be other.
The feedback control circuit is used for monitoring and adjusting the output voltage of the power supply main circuit in real time so as to maintain the stability of the output voltage of the LED driving power supply.
The primary side control circuit comprises a switch control chip UB101 and a peripheral circuit thereof, wherein a COMP pin of the switch control chip is a feedback end of the primary side control circuit, and the switch control chip UB101 outputs a control signal to the peripheral circuit thereof through an input voltage of the COMP pin so as to control the output voltage of the power supply main circuit to be stable. When the input voltage of the COMP pin is pulled down to a certain limit value, the switch control chip is triggered to stop working, so that the LED driving power supply is switched off and outputs, and power supply for a load is stopped.
As shown in fig. 2, for the constant current driving circuit shown in fig. 1, the present invention provides an over-temperature protection circuit, which includes a switch control chip UB101, a feedback control circuit 10, a switch circuit 20 and at least one over-temperature detection circuit 30.
The switch control chip UB101 includes a feedback input terminal, in the example of fig. 2, the feedback input terminal of the switch control chip UB101 is a COMP pin thereof, and in other examples, when the switch control chip UB101 is a control chip for implementing other signals of the same function, the feedback input terminal thereof may also be a corresponding pin thereof.
In this embodiment, the feedback control circuit 10 further includes a controllable precise voltage regulator UB102, a current output terminal of the light emitting diode PCB101A is connected to a cathode of the controllable precise voltage regulator UB102, an anode of the controllable precise voltage regulator UB102 is grounded, and a reference electrode of the controllable precise voltage regulator UB102 is connected to a 12V power output terminal of the constant current control circuit through a resistor R135.
In other examples, the feedback control circuit may also be in other forms as long as the feedback control circuit includes the optical coupler in the above example, and outputs a feedback signal to the switch control chip UB101 through the optical coupler.
The switch circuit 20 includes a first terminal 21 for connecting with a current output terminal of the light emitting diode PCB101A, a second terminal 22 for grounding, and a controlled terminal 23, wherein when a voltage of the controlled terminal 23 reaches a controlled voltage, the first terminal 21 and the second terminal 22 of the switch circuit 20 are turned on.
The utility model discloses an excess temperature detection circuitry can be including one or more, for every excess temperature detection circuitry 30, including power end 31, earthing terminal 32, voltage output end 33, thermistor NTC1 and resistance R1, thermistor NTC1 with resistance R1 connect in after establishing ties each other power end 31 with between the earthing terminal 32, voltage output end 33 connect in thermistor NTC1 with between resistance R1, voltage output end 33 still with switching circuit 20's controlled end 23 is connected, power end 31 can be for connecting the power that constant current control circuit exported.
In fig. 2, the thermistor NTC1 is a negative temperature coefficient thermistor, a first terminal of the thermistor NTC1 is connected to the power source terminal 31, a second terminal of the thermistor NTC1 is connected to a first terminal of the resistor R1, and a second terminal of the resistor R1 is connected to the ground terminal 32; the resistance value of the resistor R1 is configured such that, when the resistance value of the thermistor NTC1 is lower than a first set value, the voltage output terminal 33 of the over-temperature detection circuit 30 outputs a voltage equal to or higher than the controlled voltage of the switch circuit 20, thereby turning on the first terminal 21 and the second terminal 22 of the switch circuit 20.
In other examples, as shown in fig. 3, the thermistor NTC1 may also be a positive temperature coefficient thermistor, in the example of fig. 3, a first end of the resistor R1 is used for connecting the power source terminal 31, a second end of the resistor R1 is connected to a first end of the thermistor NTC1, and a second end of the thermistor NTC1 is used for connecting the ground terminal 32. The resistance value of the resistor R1 is configured such that when the resistance value of the thermistor NTC1 is higher than a second set value, the voltage output terminal 33 of the over-temperature detection circuit 30 outputs a voltage equal to or higher than the controlled voltage of the switching circuit 20.
The thermistor NTC1 is used for detecting the heating condition of the components or the power supply circuit in the LED driving power circuit, when the LED driving power circuit in fig. 1 is overloaded, the temperature of the transformer TB101 and the temperature of the diodes DB101, DB103 and DB104 in the circuit will all rise, and a more obvious heating condition will appear, therefore, in the present invention, the thermistor NTC1 may be used for detecting the temperature of the transformer or the diodes, or the temperature of the output end of the transformer or the diodes, because the temperature of the diodes rises faster than the temperature rise of the transformer when overloaded, preferably, the thermistor NTC1 may be used for detecting the temperature of the diode or diodes.
Taking fig. 2 as an example, the thermistor NTC1 is a negative temperature coefficient thermistor, and the working principle of the present invention is as follows:
when the LED driving power circuit normally operates, the resistance value distribution of the thermistor NTC1 and the resistor R1 makes the voltage output by the voltage output terminal 33 less than the controlled voltage of the switch circuit 20, the first terminal 21 and the second terminal 22 of the switch circuit 20 are disconnected, the feedback control circuit normally operates, and the switch control chip controls the output of the main power circuit according to the output of the feedback control circuit. When the LED driving power circuit is overloaded, the thermistor NTC1 detects the heating of the components in the LED driving power circuit, the temperature of the thermistor NTC1 rises simultaneously, the resistance value decreases, the voltage output by the voltage output end 33 rises simultaneously, when the resistance of the thermistor NTC1 decreases to be equal to or less than the first setting value, the voltage output from the voltage output terminal 33 is equal to or greater than the controlled voltage of the switch circuit 20, the first terminal 21 and the second terminal 22 of the switch circuit 20 are conducted, so that the cathode of the light emitting diode PCB101A in the feedback control circuit is grounded, the current passing through the light emitting diode PCB101A is increased, the No. 3 and No. 4 pins of the phototriode PCB101B are in a complete saturated conducting state, the COMP pin voltage of the switch control chip UB101 is pulled down, and the switch control chip UB101 stops outputting the control signal, and then the transformer TB101 stops outputting, so that over-temperature protection is realized, and the LED driving power supply is turned off.
The utility model discloses an excess temperature protection circuit, when LED drive power supply circuit appears overloading and generates heat, detect the situation of generating heat through thermistor to according to thermistor's characteristic, change excess temperature detection circuit's output voltage, thereby make switch circuit switch on, feedback control circuit draws down switch control chip's feedback voltage, makes switch control chip stop output control signal, thereby turn-offs LED drive power supply, the utility model discloses an excess temperature protection circuit device is few, and is with low costs, and PCB area occupied is little, has realized the quick overload of LED drive power supply and has crossed the temperature protection.
In an embodiment, as shown in fig. 4, the over-temperature protection circuit of the present invention further includes a locking circuit 40, the locking circuit 40 includes a power source terminal 41, a ground terminal 42 and a voltage stabilizing terminal 43, the ground terminal 42 of the locking circuit 40 is connected to the first terminal 21 of the switch circuit 20, the voltage stabilizing terminal 43 of the locking circuit 40 is connected to the controlled terminal 23 of the switch circuit 20, and when the first terminal 21 and the second terminal 22 of the switch circuit 20 are turned on, the voltage output by the voltage stabilizing terminal 43 of the locking circuit 40 is greater than or equal to the controlled voltage of the switch circuit 20.
In a specific example, as shown in fig. 5, the switch circuit 20 includes a controllable precision voltage regulator UB103, a cathode K of the controllable precision voltage regulator UB103 is a first end 21 of the switch circuit 20, an anode a of the controllable precision voltage regulator UB103 is a second end 22 of the switch circuit 20, a reference electrode R of the controllable precision voltage regulator UB103 is a controlled end 23 of the switch circuit 20, and a controlled voltage of the switch circuit 20 is a reference voltage of the controllable precision voltage regulator UB 103. The specific model of the controllable precise voltage-stabilizing source UB103 can be TL431, and the reference voltage of the controllable precise voltage-stabilizing source UB is 2.5V.
In a specific example, as shown in fig. 5, the latch circuit 40 includes a PNP transistor Q701, a fourth resistor R701, and a fifth resistor R702.
An emitter E of the PNP triode Q701 is connected with a power supply end of the locking circuit, a base set B of the PNP triode Q701 is connected with the power supply end of the locking circuit through the fourth resistor R701, the base set B of the PNP triode Q701 is further connected with a grounding end of the locking circuit through the fifth resistor R702, and a collector C of the PNP triode Q701 is connected with a voltage stabilizing end of the locking circuit.
When the voltage of the reference electrode R of the controllable precise voltage-stabilizing source UB103 is greater than the reference voltage, the cathode K and the anode A of the controllable precise voltage-stabilizing source UB103 are conducted, so that the base set B of the PNP triode Q701 is grounded through a fifth resistor, the collector C and the emitter E of the PNP triode Q701 are conducted, the power supply end of the locking circuit provides locking voltage greater than the reference voltage for the reference electrode of the controllable precise voltage-stabilizing source UB103 through the emitter E and the collector C of the PNP triode Q701, the cathode K and the anode A of the controllable precise voltage-stabilizing source UB103 are kept in a conducting state to form a locking state, and unlocking can be realized only by cutting off the voltage of the power supply end of the locking circuit.
In one embodiment, as shown in fig. 6, the constant current control circuit of the LED driving power supply includes a first constant current boosting unit for outputting a LED constant current driving power supply VBL, and the first constant current boosting unit includes a first diode DB104 and a first electrolytic capacitor EB105, wherein a current output end of the first diode DB104 is provided with a first copper sheet for serving as a conductive element to transmit a current output from the first diode DB104 to the LED.
The over-temperature detection circuit comprises a first over-temperature detection circuit 61, the first over-temperature detection circuit 61 comprises a first thermistor NTC1 and a first resistor R704 which are connected in series, and the first thermistor NTC1 is attached to the first copper sheet, so that when the LED driving circuit is overloaded, the first thermistor NTC1 can detect the temperature rise of the output end of the first diode DB104 at the first time by detecting the temperature of the first copper sheet.
In one embodiment, a power supply end of the first over-temperature detection circuit is used for being connected to an output end of the first constant-current boosting unit.
In an embodiment, as shown in fig. 6, the constant current control circuit of the LED driving power supply further includes a second constant current boosting unit for outputting 12V chip driving power, and the second constant current boosting unit includes a second diode DB101 and a second electrolytic capacitor EB101, wherein a current output end of the second diode DB101 is provided with a second copper sheet, and the second copper sheet is used as a conductive element for transmitting a current output from the second diode DB101 to the chip for supplying power.
Correspondingly, the over-temperature detection circuit comprises a second over-temperature detection circuit 62, the second over-temperature detection circuit 62 comprises a second thermistor NTC2 and a second resistor R705 which are connected in series, the second thermistor NTC2 is attached to the second copper sheet, so that when a chip power supply circuit in the LED driving circuit is overloaded, the second thermistor NTC2 can detect the temperature rise of the output end of the second diode DB101 at the first time by detecting the temperature of the second copper sheet.
In one embodiment, a power supply end of the second over-temperature detection circuit is used for being connected to an output end of the second constant-current boosting unit.
In an embodiment, as shown in fig. 6, the constant current control circuit of the LED driving power supply further includes a third constant current boosting unit for outputting 18V auxiliary power, and the third constant current boosting unit includes a third diode DB101 and a third electrolytic capacitor EB104, wherein a current output end of the third diode DB103 is provided with a third copper sheet, and the third copper sheet is used as a conductive element to transmit a current output from the third diode DB 103.
Correspondingly, the over-temperature detection circuit comprises a third over-temperature detection circuit 63, the third over-temperature detection circuit 63 comprises a third thermistor NTC3 and a third resistor R706 which are connected in series, the third thermistor NTC3 is attached to the third copper sheet, so that when an auxiliary power supply circuit in the LED driving circuit is overloaded, the third thermistor NTC3 can detect the temperature rise of the output end of the third diode DB103 at the first time by detecting the temperature of the third copper sheet.
In one embodiment, a power supply terminal of the third over-temperature detection circuit is used for being connected to an output terminal of the third constant current boosting unit.
Fig. 7 is a schematic structural diagram of an LED driving power supply provided by the present invention, which includes a power main circuit 71, a constant current control circuit 72, and an over-temperature protection circuit 73 according to any of the above embodiments.
The power supply main circuit 71 is configured to output a voltage signal to the constant current control circuit 72, and the constant current control circuit 72 is configured to convert the voltage signal into a constant current electrical signal.
The feedback control circuit of the over-temperature protection circuit 73 is configured to monitor and adjust the output voltage of the main power supply circuit 71 in real time, and output a feedback signal to the switch control chip UB101, and the switch control chip UB101 controls the output of the main power supply circuit 71 according to the feedback signal.
Fig. 8 is a schematic structural diagram of the driving board card provided by the present invention, and the driving board card 80 includes the LED driving power supply 81 according to any of the above embodiments.
Fig. 9 is a schematic structural diagram of a display device provided by the present invention, and the display device 90 includes an LED load 91 and the driving board 80 according to any of the above embodiments; and the current input end of the LED load 91 is connected with the backlight current output end of the constant current control circuit of the LED driving power supply.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention.
Claims (15)
1. An over-temperature protection circuit, comprising:
the control circuit comprises a switch control chip, a feedback control circuit, a switch circuit and at least one over-temperature detection circuit;
the switch control chip comprises a feedback input end;
the feedback control circuit comprises an optocoupler, the optocoupler comprises a light emitting diode and an optical signal converter, the current input end of the light emitting diode is connected with a power supply, the current input end of the optical signal converter is connected with the feedback input end of the switch control chip, and the current output end of the optical signal converter is grounded;
the switch circuit comprises a first end connected with the current output end of the light-emitting diode, a second end connected with the ground and a controlled end;
for each over-temperature detection circuit, the over-temperature detection circuit comprises a power supply end, a grounding end, a voltage output end, a thermistor and a resistor, wherein the thermistor and the resistor are connected in series and then are connected between the power supply end and the grounding end, the voltage output end is connected between the thermistor and the resistor, and the voltage output end is also connected with a controlled end of the switch circuit;
when the voltage of the controlled end of the switch circuit reaches the controlled voltage, the first end and the second end of the switch circuit are conducted, the current of the light-emitting diode is increased, the light signal converter is conducted in a saturated mode, the voltage of the feedback input end of the switch control chip is reduced, the switch control chip stops outputting the driving signal, and the LED driving power supply is turned off.
2. The over-temperature protection circuit according to claim 1, wherein:
the thermistor is a negative temperature coefficient thermistor, the first end of the thermistor is used for connecting the power supply end, the second end of the thermistor is connected with the first end of the resistor, and the second end of the resistor is used for connecting the grounding end;
the resistance value of the resistor is configured to enable the voltage output by the voltage output end of the over-temperature detection circuit to be larger than or equal to the controlled voltage of the switch circuit when the resistance value of the thermistor is lower than a first set value.
3. The over-temperature protection circuit according to claim 1, wherein:
the thermistor is a positive temperature coefficient thermistor, the first end of the thermistor is used for connecting the power supply end, the second end of the thermistor is connected with the first end of the thermistor, and the second end of the thermistor is used for connecting the grounding end;
the resistance value of the resistor is configured to enable the voltage output by the voltage output end of the over-temperature detection circuit to be larger than or equal to the controlled voltage of the switch circuit when the resistance value of the thermistor is higher than a second set value.
4. The over-temperature protection circuit according to claim 1, wherein:
the switching circuit comprises a controllable precise voltage-stabilizing source, wherein the cathode of the controllable precise voltage-stabilizing source is the first end of the switching circuit, the anode of the controllable precise voltage-stabilizing source is the second end of the switching circuit, and the reference end of the controllable precise voltage-stabilizing source is the controlled end of the switching circuit.
5. An over-temperature protection circuit according to any one of claims 1 to 4, wherein:
the LED driving power supply comprises a first constant current boosting unit for outputting the LED constant current driving power supply, the first constant current boosting unit comprises a first diode, and the output end of the first diode is provided with a first copper sheet;
the over-temperature detection circuit comprises a first over-temperature detection circuit, the first over-temperature detection circuit comprises a first thermistor and a first resistor which are connected in series, and the first thermistor is attached to the first copper sheet.
6. An over-temperature protection circuit according to claim 5, wherein:
and the power supply end of the first over-temperature detection circuit is used for being connected to the output end of the first constant-current boosting unit.
7. An over-temperature protection circuit according to claim 5, wherein:
the constant current driving circuit comprises a second constant current boosting unit for outputting a 12V chip driving power supply, the second constant current boosting unit comprises a second diode, and the output end of the second diode is provided with a second copper sheet;
the over-temperature detection circuit comprises a second over-temperature detection circuit, the second over-temperature detection circuit comprises a second thermistor and a second resistor which are connected in series, and the second thermistor is attached to the second copper sheet.
8. An over-temperature protection circuit according to claim 7, wherein:
and the power supply end of the second over-temperature detection circuit is used for being connected to the output end of the second constant-current boosting unit.
9. An over-temperature protection circuit according to claim 5, wherein:
the constant current driving circuit comprises a third constant current boosting unit for outputting the 18V auxiliary power supply, the third constant current boosting unit comprises a third diode, and the output end of the third diode is provided with a third copper sheet;
the over-temperature detection circuit comprises a third over-temperature detection circuit, the third over-temperature detection circuit comprises a third thermistor and a third resistor which are connected in series, and the third thermistor is attached to the third copper sheet.
10. An over-temperature protection circuit according to claim 9, wherein:
and the power supply end of the third over-temperature detection circuit is used for being connected to the output end of the third constant-current boosting unit.
11. The excess temperature protection circuit according to any one of claims 1 to 4, wherein:
the over-temperature protection circuit further comprises a locking circuit;
the locking circuit comprises a power supply end, a grounding end and a voltage stabilizing end, the grounding end of the locking circuit is connected with the first end of the switch circuit, the voltage stabilizing end of the locking circuit is connected with the controlled end of the switch circuit, and when the first end and the second end of the switch circuit are conducted, the voltage output by the voltage stabilizing end of the locking circuit is larger than or equal to the controlled voltage of the switch circuit.
12. The over-temperature protection circuit according to claim 11, wherein:
the locking circuit comprises a PNP triode, a fourth resistor and a fifth resistor;
the emitting electrode of the PNP triode is connected with the power supply end of the locking circuit, the base set of the PNP triode is connected with the power supply end of the locking circuit through the fourth resistor, the base set of the PNP triode is further connected with the grounding end of the locking circuit through the fifth resistor, and the collecting electrode of the PNP triode is connected to the voltage stabilizing end of the locking circuit.
13. An LED drive power supply characterized in that:
the over-temperature protection circuit comprises a power supply main circuit, a constant current control circuit and the over-temperature protection circuit as claimed in any one of claims 1 to 12;
the power supply main circuit is used for outputting a voltage signal to the constant current control circuit, and the constant current control circuit is used for converting the voltage signal into a constant current electrical signal;
the feedback control circuit is used for monitoring and adjusting the output voltage of the power main circuit in real time and outputting a feedback signal to the switch control chip, and the switch control chip controls the output of the power main circuit according to the feedback signal.
14. A drive integrated circuit board, its characterized in that:
comprising the LED driving power supply according to claim 13.
15. A display device characterized by:
comprising an LED load and a driver board as claimed in claim 14;
and the current input end of the LED load is connected with the backlight current output end of the constant current control circuit of the LED driving power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020985419.8U CN212519507U (en) | 2020-06-02 | 2020-06-02 | Over-temperature protection circuit, LED driving power supply, driving board card and display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020985419.8U CN212519507U (en) | 2020-06-02 | 2020-06-02 | Over-temperature protection circuit, LED driving power supply, driving board card and display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212519507U true CN212519507U (en) | 2021-02-09 |
Family
ID=74382102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020985419.8U Active CN212519507U (en) | 2020-06-02 | 2020-06-02 | Over-temperature protection circuit, LED driving power supply, driving board card and display device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212519507U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023273908A1 (en) * | 2021-06-30 | 2023-01-05 | 广州视源电子科技股份有限公司 | Overload protection circuit |
-
2020
- 2020-06-02 CN CN202020985419.8U patent/CN212519507U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023273908A1 (en) * | 2021-06-30 | 2023-01-05 | 广州视源电子科技股份有限公司 | Overload protection circuit |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101916548B (en) | Control circuit of light-emitting diode (LED) lamp tube of liquid crystal display | |
| CN102842893B (en) | Short-circuit protection and control circuit for LED (Lighnt emitting Diode) strip lamp | |
| CN212519502U (en) | Remote controller control circuit, circuit board and remote controller | |
| CN212519507U (en) | Over-temperature protection circuit, LED driving power supply, driving board card and display device | |
| CN218920268U (en) | Voltage selection circuit, power supply circuit and electronic equipment | |
| CN216160989U (en) | Starting circuit and starting device | |
| CN211606889U (en) | Overvoltage protection circuit, constant current drive circuit, drive integrated circuit board and electronic equipment | |
| CN209994597U (en) | Multifunctional dimming circuit and device | |
| CN211352536U (en) | Constant current load circuit, backlight adjusting circuit, driving board card and electronic equipment | |
| CN211792154U (en) | Backlight control circuit, television and intelligent panel | |
| CN209571817U (en) | IC chip protects circuit | |
| CN109587883B (en) | Light source self-adapting device and system of light emitting diode | |
| CN213073195U (en) | Negative voltage overvoltage protection circuit, LED driving power supply, driving board card and display device | |
| CN207403595U (en) | A kind of charging gun with charging instruction | |
| CN218277208U (en) | Digital dimming control circuit of LED lamp | |
| CN218301202U (en) | Power supply circuit with low standby power consumption | |
| CN217469468U (en) | Multi-path power supply control system and electronic equipment | |
| CN218301211U (en) | Power-down protection power supply circuit and protection system | |
| CN212344116U (en) | Startup loop adjusting circuit, LED driving power supply, driving board card and display device | |
| CN211826405U (en) | Power input/output state display circuit | |
| CN220358027U (en) | Multi-opening multi-closing optocoupler relay | |
| CN214253042U (en) | Output signal control circuit and device | |
| CN213694233U (en) | LED constant-brightness adjusting circuit and electronic equipment | |
| CN213243518U (en) | Power-down protection circuit, LED driving power supply, driving board card and display device | |
| CN214279848U (en) | Luminous keyboard module |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |