CN213073195U - Negative voltage overvoltage protection circuit, LED driving power supply, driving board card and display device - Google Patents
Negative voltage overvoltage protection circuit, LED driving power supply, driving board card and display device Download PDFInfo
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- CN213073195U CN213073195U CN202021526863.XU CN202021526863U CN213073195U CN 213073195 U CN213073195 U CN 213073195U CN 202021526863 U CN202021526863 U CN 202021526863U CN 213073195 U CN213073195 U CN 213073195U
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- 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
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- 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]
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Abstract
The utility model relates to a negative voltage overvoltage crowbar. The utility model discloses a negative voltage overvoltage protection circuit, which comprises a negative voltage sampling unit, wherein the input end is used for collecting a negative voltage signal output by an LED driving power supply, and the output end is connected with the first end of a first resistor; the input end of the first positive voltage sampling unit is used for collecting a first positive voltage signal, and the output end of the first positive voltage sampling unit is connected with the second end of the first resistor; the conduction switch comprises a controlled end, a current input end and a current output end, the controlled end is connected with the second end of the first resistor, and the current output end is grounded; the input end of the second positive voltage sampling unit is used for collecting a second positive voltage signal and is connected with the current input end, and the output end of the second positive voltage sampling unit is connected with the positive input end of the comparison unit; and the negative input end of the comparison unit is used for connecting reference voltage, and the output end of the comparison unit is used for connecting an overvoltage protection pin of the driving chip. The utility model discloses a negative voltage overvoltage crowbar, simple structure, it is with low costs, realized LED drive power supply's negative voltage overvoltage crowbar.
Description
Technical Field
The utility model relates to an electronic circuit's technical field especially relates to a negative voltage overvoltage crowbar, 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 conventional LED driving power circuit, an overvoltage protection circuit is usually provided, but the overvoltage protection circuit provided in the conventional LED driving power circuit is usually a positive voltage protection circuit, and there is no related overvoltage protection circuit for a negative voltage output by the LED driving power circuit.
SUMMERY OF THE UTILITY MODEL
Based on this, the utility model provides a negative voltage overvoltage crowbar, the utility model discloses negative voltage overvoltage crowbar, simple structure, it is with low costs, realized LED drive power supply's negative voltage overvoltage crowbar.
In a first aspect, the present invention provides a negative voltage overvoltage protection circuit, including: the device comprises a first resistor, a negative voltage sampling unit, a first positive voltage sampling unit, a conducting switch, a comparison unit and a second positive voltage sampling unit;
the input end of the negative voltage sampling unit is used for collecting a negative voltage signal output by the LED driving power supply, and the output end of the negative voltage sampling unit is connected with the first end of the first resistor;
the input end of the first positive voltage sampling unit is used for collecting a first positive voltage signal, and the output end of the first positive voltage sampling unit is connected with the second end of the first resistor;
the conduction switch comprises a controlled end, a current input end and a current output end, the controlled end is connected with the second end of the first resistor, and the current output end is grounded;
the input end of the second positive voltage sampling unit is used for collecting a second positive voltage signal and is connected with the current input end, and the output end of the second positive voltage sampling unit is connected with the positive input end of the comparison unit;
the negative input end of the comparison unit is used for being connected with reference voltage, and the output end of the comparison unit is used for being connected with an overvoltage protection pin of the driving chip.
Optionally, the negative voltage sampling unit includes a second resistor and a third resistor, the second resistor and the third resistor are connected in series between the input terminal of the negative voltage sampling unit and ground, and the output terminal of the negative voltage sampling unit is a common connection terminal between the second resistor and the third resistor.
Optionally, the first positive voltage sampling unit includes a fourth resistor and a fifth resistor, the fourth resistor and the fifth resistor are connected in series between the input terminal of the first positive voltage sampling unit and ground, and the output terminal of the first positive voltage sampling unit is a common connection terminal between the fourth resistor and the fifth resistor.
Optionally, the conducting switch is a controllable precision voltage-stabilizing source, the controlled end is a reference end of the controllable precision voltage-stabilizing source, the current input end is a cathode of the controllable precision voltage-stabilizing source, and the current output end is an anode of the controllable precision voltage-stabilizing source.
Optionally, the second positive voltage sampling unit includes a sixth resistor, a first end of the sixth resistor is used for being connected to the input end of the second positive voltage sampling unit and connected to the current input end, and a second end of the sixth resistor is connected to the positive input end of the comparing unit.
Optionally, the comparison unit includes an operational amplifier, a positive input end of the operational amplifier is connected to an output end of the second positive voltage sampling unit, a negative input end of the operational amplifier is connected to the reference voltage, and an output end of the operational amplifier is used for connecting an overvoltage protection pin of the driver chip.
Optionally, the first positive voltage signal is the same as the reference voltage.
In a second aspect, the present invention provides a LED driving power supply, including:
a power main circuit and the negative voltage overvoltage protection circuit of the first aspect of the present invention, the power main circuit including a positive voltage output terminal and a negative voltage output terminal;
and the input end of the negative voltage sampling unit is connected with the negative voltage output end.
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 present invention provides a display device, including the third aspect of the present invention the driving board.
The utility model discloses an among the negative voltage overvoltage crowbar, gather the negative voltage signal of LED drive power supply output through negative voltage sampling unit, when the negative voltage signal was excessive pressure, pull the voltage signal that first positive voltage sampling unit was gathered, make the on-off end, the reference voltage signal that second positive voltage sampling unit was gathered to be higher than comparing unit negative input end, and send to comparing unit's positive input end, thereby make comparing unit's output high level, trigger LED drive power supply's driver chip's overvoltage protection, the utility model discloses negative voltage overvoltage crowbar, simple structure, it is with low costs.
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 negative voltage overvoltage protection circuit according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a negative voltage overvoltage protection circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of an LED driving power supply according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a driving board card according to an embodiment of the present invention;
fig. 5 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.
The utility model provides a negative voltage overvoltage crowbar can be when LED drive power supply's alternating current power supply is not enough or loses the electricity, cuts off the power supply to the back level power fast.
As shown in fig. 1, in one embodiment, the negative voltage overvoltage protection circuit of the present invention includes a negative voltage sampling unit 1, a first positive voltage sampling unit 2, a first resistor R1, a conducting switch 3, a second positive voltage sampling unit 4, and a comparison unit 5.
The input end of the negative voltage sampling unit 1 is used for collecting a negative voltage signal output by the LED driving power supply, and the output end of the negative voltage sampling unit is connected with the first end of the first resistor R1 and used for outputting the collected negative voltage signal to the first end of the first resistor R1.
The input end of the first positive voltage sampling unit 2 is used for collecting a first positive voltage signal VCC1, and the output end of the first positive voltage sampling unit 2 is connected with the second end of the first resistor R1, and is used for outputting the collected first positive voltage signal to the second end of the first resistor R1. The first positive voltage signal VCC1 may be an auxiliary voltage signal output by the LED driving power supply, such as an auxiliary voltage signal of 5V, 12V or 18V, and in some examples, the first positive voltage signal VCC1 may also be a more stable reference voltage signal, and the reference voltage signal may be 2.5V.
The conducting switch 3 comprises a controlled end, a current input end and a current output end, the controlled end is connected with the second end of the first resistor R1, the current output end is grounded, the conducting switch 3 conducts or cuts off the current input end and the current output end according to a voltage signal received by the controlled end, and the conducting switch can be a controllable precise voltage-stabilizing source, a triode, a field effect transistor and other switching devices.
The input end of the second positive voltage sampling unit 4 is used for collecting a second positive voltage signal and is connected with the current input end of the conducting switch 3, and the output end of the second positive voltage sampling unit 4 is connected with the positive input end of the comparing unit 5 and is used for outputting the collected second positive voltage signal to the positive input end of the comparing unit 5; the first positive voltage signal VCC1 may be an auxiliary voltage signal output by the LED driving power supply, such as an auxiliary voltage signal of 5V, 12V, or 18V.
The negative input end of the comparison unit 5 is used for connecting a reference voltage, and the output end OVP of the comparison unit 5 is used for connecting an overvoltage protection pin of a driving chip.
In some examples, the reference voltage may be 2.5V. The comparing unit 5 is configured to compare the voltage signals of the positive input terminal and the negative input terminal, and output a level signal according to a comparison result.
The overvoltage protection circuit with the negative voltage can be used for LED driving power supplies of various terminal devices. For example, a display device such as a television, a smart panel, etc., the load may be a backlight light source (e.g., an LED light bar), etc., and a driving chip for constant current control is provided in the LED driving power supply of the terminal device.
The embodiment of the utility model provides a theory of operation does:
when the LED driving power supply normally works, the voltage signal collected by the first positive voltage sampling unit 2 is higher than the controlled voltage of the conduction switch 3, so that the current input end and the current output end of the conduction switch are conducted, the input end of the second positive voltage sampling unit 4 is grounded and pulled down the voltage of the positive input end of the comparison unit 5 is lower than the reference voltage of the negative input end, the output of the output end of the comparison unit 5 is at a low level, and the overvoltage protection of the driving chip can not be triggered.
When the negative voltage LED output by the LED driving power supply is overvoltage, the voltage of the output end of the first positive voltage sampling unit 2 is pulled down by the negative voltage signal collected by the negative voltage sampling unit 1 through the first resistor R1, when the voltage of the output end of the first positive voltage sampling unit 2 is lower than the controlled voltage of the conduction switch 3, the current input end and the current output end of the conduction switch are cut off, so that the second positive voltage signal is collected by the second positive voltage sampling unit 4, and the voltage signal greater than the reference voltage is output to the positive input end of the comparison unit 5, at this moment, the voltage of the positive input end of the comparison unit 5 is greater than the voltage of the negative input end, the output end of the comparison unit 5 is at a high level, and the overvoltage protection of the driving.
The embodiment of the utility model provides an in, gather the negative voltage signal of LED drive power supply output through the negative voltage sampling unit, when the negative voltage signal is excessive pressure, pull the voltage signal that first positive voltage sampling unit was gathered down for the on-off ends, the second positive voltage sampling unit is gathered the reference voltage signal that is higher than the comparison unit negative input end, and sends to the positive input end of comparison unit, thereby makes the output high level of comparison unit, triggers LED drive power supply's drive chip's overvoltage protection, the utility model discloses a negative voltage overvoltage protection circuit, simple structure, it is with low costs.
In an embodiment, as shown in fig. 2, the negative voltage sampling unit includes a second resistor R2 and a third resistor R3, the second resistor R2 and the third resistor R3 are connected in series between the input terminal of the negative voltage sampling unit and ground, the second resistor R2 and the third resistor R3 form a voltage dividing circuit, and the output terminal of the negative voltage sampling unit is a common connection terminal between the second resistor R2 and the third resistor R3.
In other examples, the second resistor R2 or the third resistor R3 may be implemented by a series connection of a plurality of resistors.
In one embodiment, as shown in fig. 2, the first positive voltage sampling unit includes a fourth resistor R4 and a fifth resistor R5, the fourth resistor R4 and the fifth resistor R5 are connected in series between the input terminal of the first positive voltage sampling unit and ground, the fourth resistor R4 and the fifth resistor R5 form a voltage dividing circuit, and the output terminal of the first positive voltage sampling unit is a common connection terminal between the fourth resistor R4 and the fifth resistor R5.
In an embodiment, as shown in fig. 2, the conducting switch is a controllable precision voltage regulator U1, the controlled terminal is a reference terminal R of the controllable precision voltage regulator U1, the current input terminal is a cathode K of the controllable precision voltage regulator U1, the current output terminal is an anode a of the controllable precision voltage regulator U1, and the anode a of the controllable precision voltage regulator U1 is grounded.
In an embodiment, as shown in fig. 2, the second positive voltage sampling unit 4 includes a sixth resistor R6, a first end of the sixth resistor R6 is used for being connected to the input end of the second positive voltage sampling unit and to the current input end of the controllable precision voltage regulator U1, i.e. the cathode K, and a second end of the sixth resistor R6 is connected to the positive input end of the comparing unit.
In one embodiment, as shown in fig. 2, the comparing unit includes an operational amplifier U2, a positive input terminal of the operational amplifier U2 is connected to an output terminal of the second positive voltage sampling unit, i.e., a second terminal of the sixth resistor R6, a negative input terminal of the operational amplifier U2 is connected to the reference voltage 2.5VREF, and an output terminal of the operational amplifier U2 is used for connecting an over-voltage protection pin of the driver chip.
In the embodiment of the present application, the type and model of the operational amplifier U2 are not particularly limited, and may be a general-purpose operational amplifier, a high-speed operational amplifier, a low-power operational amplifier, or the like.
In one embodiment, as shown in fig. 2, the first positive voltage signal is the same as the reference voltage, and both are 2.5V.
Fig. 3 is a schematic structural diagram of an LED driving power supply provided by the present invention, which includes a power main circuit 31 and a negative voltage overvoltage protection circuit 32 according to any of the above embodiments.
The power main circuit 31 comprises a positive voltage output end LED + and a negative voltage output end LED-; the input end of the negative voltage sampling unit 1 is connected with the negative voltage output end LED-.
Fig. 4 is a schematic structural diagram of the driving board card provided by the present invention, and the driving board card 40 includes the LED driving power supply 41 according to any of the above embodiments.
Fig. 5 is a schematic structural diagram of a display device provided by the present invention, the display device 50 includes an LED load 51 and the driving board 40 according to any of the above embodiments; two ends of the LED load 51 are respectively connected with a positive voltage output end LED + and a negative voltage output end LED-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 (10)
1. A negative voltage overvoltage protection circuit, comprising: the device comprises a first resistor, a negative voltage sampling unit, a first positive voltage sampling unit, a conducting switch, a comparison unit and a second positive voltage sampling unit;
the input end of the negative voltage sampling unit is used for collecting a negative voltage signal output by the LED driving power supply, and the output end of the negative voltage sampling unit is connected with the first end of the first resistor;
the input end of the first positive voltage sampling unit is used for collecting a first positive voltage signal, and the output end of the first positive voltage sampling unit is connected with the second end of the first resistor;
the conduction switch comprises a controlled end, a current input end and a current output end, the controlled end is connected with the second end of the first resistor, and the current output end is grounded;
the input end of the second positive voltage sampling unit is used for collecting a second positive voltage signal and is connected with the current input end, and the output end of the second positive voltage sampling unit is connected with the positive input end of the comparison unit;
the negative input end of the comparison unit is used for being connected with reference voltage, and the output end of the comparison unit is used for being connected with an overvoltage protection pin of the driving chip.
2. The negative voltage overvoltage protection circuit of claim 1, wherein:
the negative voltage sampling unit comprises a second resistor and a third resistor, the second resistor and the third resistor are mutually connected in series between the input end of the negative voltage sampling unit and the ground, and the output end of the negative voltage sampling unit is a common connecting end between the second resistor and the third resistor.
3. The negative voltage overvoltage protection circuit of claim 1, wherein:
the first positive voltage sampling unit comprises a fourth resistor and a fifth resistor, the fourth resistor and the fifth resistor are mutually connected in series between the input end of the first positive voltage sampling unit and the ground, and the output end of the first positive voltage sampling unit is a common connection end between the fourth resistor and the fifth resistor.
4. The negative voltage overvoltage protection circuit of claim 1, wherein:
the conducting switch is a controllable precise voltage-stabilizing source, the controlled end is a reference end of the controllable precise voltage-stabilizing source, the current input end is a cathode of the controllable precise voltage-stabilizing source, and the current output end is an anode of the controllable precise voltage-stabilizing source.
5. The negative voltage overvoltage protection circuit of claim 1, wherein:
the second positive voltage sampling unit comprises a sixth resistor, the first end of the sixth resistor is used for being connected with the input end of the second positive voltage sampling unit and connected with the current input end, and the second end of the sixth resistor is connected with the positive input end of the comparison unit.
6. The negative voltage overvoltage protection circuit of claim 1, wherein:
the comparison unit comprises an operational amplifier, the positive input end of the operational amplifier is connected with the output end of the second positive voltage sampling unit, the negative input end of the operational amplifier is connected with the reference voltage, and the output end of the operational amplifier is used for being connected with an overvoltage protection pin of the driving chip.
7. The negative voltage overvoltage protection circuit of claim 1, wherein:
the first positive voltage signal is the same as the reference voltage.
8. An LED driving power supply, comprising:
a power supply main circuit comprising a positive voltage output terminal and a negative voltage output terminal, and the negative voltage overvoltage protection circuit of any one of claims 1 to 7;
and the input end of the negative voltage sampling unit is connected with the negative voltage output end.
9. A drive integrated circuit board, its characterized in that includes:
the LED driving power supply according to claim 8.
10. A display device characterized by:
comprising a drive board as claimed in claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021526863.XU CN213073195U (en) | 2020-07-28 | 2020-07-28 | Negative voltage overvoltage protection circuit, LED driving power supply, driving board card and display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021526863.XU CN213073195U (en) | 2020-07-28 | 2020-07-28 | Negative voltage overvoltage protection circuit, LED driving power supply, driving board card and display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213073195U true CN213073195U (en) | 2021-04-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021526863.XU Active CN213073195U (en) | 2020-07-28 | 2020-07-28 | Negative voltage overvoltage protection circuit, LED driving power supply, driving board card and display device |
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| Country | Link |
|---|---|
| CN (1) | CN213073195U (en) |
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- 2020-07-28 CN CN202021526863.XU patent/CN213073195U/en active Active
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