CN219644153U - Backlight chip protection circuit, circuit board, backlight board and display device - Google Patents
Backlight chip protection circuit, circuit board, backlight board and display device Download PDFInfo
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- CN219644153U CN219644153U CN202320173512.2U CN202320173512U CN219644153U CN 219644153 U CN219644153 U CN 219644153U CN 202320173512 U CN202320173512 U CN 202320173512U CN 219644153 U CN219644153 U CN 219644153U
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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
- 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]
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Abstract
The utility model discloses a backlight chip protection circuit, a circuit board, a backlight plate and display equipment. The backlight chip protection circuit comprises a first switching device and a first diode, wherein the control end of the first switching device and the cathode of the first diode are used for being connected with a power supply of the backlight chip, the anode of the first diode and the input end of the first switching device are used for being connected with an LED control pin of the backlight chip, and the output end of the first switching device is used for being connected with the cathode of an LED light bar. When the voltage difference between the control end and the input end of the first switching device is larger than a preset conducting voltage value, the input end and the output end of the first switching device are conducted. Through the technical means, the technical problem that the voltage and the current of the built-in dimming MOS tube of the backlight chip exceed the safety specification when the LED lamp strip is in short circuit in the prior art is solved, the built-in dimming MOS tube of the backlight chip is protected from being damaged, and the safety of the backlight chip is improved.
Description
Technical Field
The present utility model relates to the field of display technologies, and in particular, to a backlight chip protection circuit, a circuit board, a backlight board, and a display device.
Background
Most of the current displays use LED (light-emitting diode) light bars as backlight sources, and the backlight chips control the brightness of the LED light bars.
In the prior art, the positive pole of the LED light bar is connected with a power supply, the negative pole of the LED light bar is connected with an LED control pin of a backlight chip, and a dimming MOS (MOSFET) tube is arranged in the backlight chip to control the LED control pin to output high-low level signals. When the LED lamp strip works normally, the dimming MOS tube is conducted, the LED control pin outputs a low-level signal, and the LED lamp strip is conducted and emits light. However, under the influence factors such as environment, the short circuit site may appear between the positive electrode and the negative electrode of the LED light bar, and when the positive electrode and the negative electrode of the LED light bar are in short circuit, the positive electrode of the LED light bar is high voltage, and the negative electrode of the LED light bar can instantly become high voltage with the same voltage as the positive electrode, so that the voltage of the LED control pin exceeds the withstand voltage specification of the dimming MOS tube. And the LED lamp strip is accompanied with the appearance of heavy current, and the heavy current exceeds the impact current specification of the MOS pipe of adjusting luminance, and the MOS pipe of adjusting luminance short circuit burns out, and backlight chip inefficacy, backlight chip's security is lower.
Disclosure of Invention
The utility model provides a backlight chip protection circuit, a circuit board, a backlight board and display equipment, wherein the backlight chip protection circuit is additionally arranged between the negative electrode of an LED lamp strip and an LED control pin of the backlight chip, the voltage of the LED control pin is clamped at the power supply voltage of the backlight chip when the LED lamp strip is in short circuit through the backlight chip protection circuit, and meanwhile, a part of transient current when the LED lamp strip is in short circuit is separated, so that the technical problem that the voltage and the current of a built-in dimming MOS tube of the backlight chip exceed safety specifications when the LED lamp strip is in short circuit in the prior art is solved, the built-in dimming MOS tube of the backlight chip is protected from being damaged, and the safety of the backlight chip is improved.
In a first aspect, the present utility model provides a backlight chip protection circuit, including a first switching device and a first diode, wherein:
the control end of the first switching device and the cathode of the first diode are used for being connected with a power supply of a backlight chip, the anode of the first diode and the input end of the first switching device are used for being connected with an LED control pin of the backlight chip, and the output end of the first switching device is used for being connected with the cathode of an LED lamp strip;
when the voltage difference between the control end and the input end of the first switching device is larger than a preset conducting voltage value, the input end and the output end of the first switching device are conducted.
In a second aspect, the present utility model provides a circuit board comprising a backlight chip protection circuit as described in the first aspect.
In a third aspect, the utility model provides a backlight board, which comprises a backlight chip, an LED light bar and the circuit board according to the second aspect, wherein an LED control pin and a power supply of the backlight chip are connected with a backlight chip protection circuit of the circuit board, a negative electrode of the LED light bar is connected with the backlight chip protection circuit of the circuit board, and a positive electrode of the LED light bar is connected with a power supply.
In a fourth aspect, the present utility model provides a display device comprising a backlight as described in the third aspect.
In the utility model, when the built-in dimming MOS tube of the backlight chip is conducted, the LED control pin outputs a low-level signal, the input end and the output end of the first switch device are conducted, the negative electrode of the LED lamp strip is connected with the low-level signal, the LED lamp strip is conducted, and the LED lamp strip emits light normally. When the LED lamp strip is in short circuit, the cathode of the LED lamp strip instantly becomes high voltage the same as the anode of the LED lamp strip, the voltage of the LED control pin increases along with the voltage rising of the cathode of the LED lamp strip, the voltage of the LED control pin increases to enable the voltage difference between the control end and the input end of the first switching device to be reduced, when the voltage difference between the control end and the input end of the first switching device is reduced to a preset voltage value, the input end and the output end of the first switching device are disconnected, the voltage of the LED control pin is approximately equal to the power voltage of a backlight chip, and the power voltage of the backlight chip is far smaller than the voltage specification of the MOS tube of the built-in dimming chip. Along with the decrease of the voltage difference between the control end and the input end of the first switching device, the on-resistance of the first switching device is continuously increased, and the transient current when the LED light bar is in short circuit is greatly reduced. Before the input end and the output end of the first switching device are disconnected, the first diode is conducted and partial transient current is separated, so that the transient current is far smaller than the impact current specification of the built-in dimming MOS tube, and the voltage of the LED control pin is clamped at the power supply voltage of the backlight chip after the first diode is conducted. Through the technical means, the technical problem that the voltage and the current of the built-in dimming MOS tube of the backlight chip exceed the safety specification when the LED lamp strip is in short circuit in the prior art is solved, the built-in dimming MOS tube of the backlight chip is protected from being damaged, and the safety of the backlight chip is improved.
Drawings
Fig. 1 is a schematic structural diagram of a protection circuit for a backlight chip according to an embodiment of the present utility model;
fig. 2 is a schematic structural diagram of a backlight board according to an embodiment of the present utility model;
in the figure, 10, a backlight chip protection circuit; 20. a backlight chip; 30. LED light bar; r1, a first resistor; r2, a second resistor; q1, a first switching device; q2, a second switching device; d1, a first diode; d2, a second diode; e1, an electrolytic capacitor; l1, a first inductor; VCC, power supply of the backlight chip; LED_IC, LED control pin; SGND, ground; VIN, power supply.
Detailed Description
In order to make the objects, technical solutions and advantages of the present utility model more apparent, the following detailed description of specific embodiments of the present utility model is given with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the matters related to the present utility model are shown in the accompanying drawings. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart depicts operations (or steps) as a sequential process, many of the operations can be performed in parallel, concurrently, or at the same time. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figures. The processes may correspond to methods, functions, procedures, subroutines, and the like.
The terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged, as appropriate, such that embodiments of the present utility model may be implemented in sequences other than those illustrated or described herein, and that the objects identified by "first," "second," etc. are generally of a type, and are not limited to the number of objects, such as the first object may be one or more. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/", generally means that the associated object is an "or" relationship.
In an embodiment, an anode of the LED light bar is connected to a power supply, a cathode of the LED light bar is connected to an LED control pin of a backlight chip, and a dimming MOS (MOSFET, field effect transistor) tube is built in the backlight chip to control the LED control pin to output a high-low level signal. When the LED lamp strip works normally, the dimming MOS tube is conducted, the LED control pin outputs a low-level signal, and the LED lamp strip is conducted and emits light. When the LED lamp strip is in short circuit, the negative electrode of the LED lamp strip is changed into high voltage which is the same as that of the positive electrode, and larger transient current is generated, and the high voltage and the large current act on the LED control pin of the backlight chip, so that the dimming MOS tube is subjected to the problem that the voltage and the current exceed the withstand voltage specification and the impulse current specification, the short circuit burning out of the dimming MOS tube occurs at the maximum probability, the backlight chip fails after the short circuit burning out of the dimming MOS tube, the LED lamp strip cannot continuously emit light normally, and the backlight plate of the display device has serious faults.
In order to solve the above problems, the present embodiment provides a protection circuit for a backlight chip, which protects a built-in dimming MOS tube of the backlight chip from being damaged, and improves the safety of the backlight chip.
Fig. 1 shows a schematic structural diagram of a protection circuit for a backlight chip according to an embodiment of the present utility model. As shown in fig. 1, the backlight chip protection circuit 10 includes a first switching device Q1 and a first diode D1. The control end of the first switching device Q1 and the cathode of the first diode D1 are used for being connected with the power supply VCC of the backlight chip 20, the anode of the first diode D1 and the input end of the first switching device Q1 are used for being connected with the LED control pin led_ic of the backlight chip 20, and the output end of the first switching device Q1 is used for being connected with the cathode of the LED light bar 30. When the voltage difference between the control end and the input end of the first switching device Q1 is greater than a preset conducting voltage value, the input end and the output end of the first switching device Q1 are conducted.
In this embodiment, the on voltage is smaller than the power VCC voltage of the backlight chip 20, for example, the power VCC voltage of the backlight chip 20 is generally 3V to 5V, and the first switching device Q1 with the on voltage of 1V to 2.5V may be used. The voltage specification of the first switching device Q1 adopted in the embodiment is larger than the voltage accessed by the anode of the LED light bar 30, the capability of the first switching device Q1 for resisting impact current and transient power is strong, and the short circuit of the LED light bar 30 does not damage the first switching device Q1.
For example, when the backlight chip 20 works normally, the built-in dimming MOS transistor of the backlight chip 20 is turned on, and the LED control pin led_ic of the backlight chip 20 outputs a low level signal, i.e. the input end of the first switching device Q1 is connected to the low level signal. The control end of the first switching device Q1 is connected to the power VCC voltage of the backlight chip 20, and the voltage difference between the control end and the input end of the first switching device Q1 is greater than the on voltage value of the first switching device Q1, at this time, the output end and the input end of the first switching device Q1 are turned on. After the first switching device Q1 is turned on, the negative electrode of the LED light bar 30 is connected to the low-level signal output by the LED control pin led_ic, at this time, the positive electrode of the LED light bar 30 is connected to the high voltage, and the negative electrode of the LED light bar 30 is connected to the low voltage, and a current from the positive electrode to the negative electrode is formed in the LED light bar 30, that is, the LED light bar 30 is turned on and emits light. The addition of the backlight chip protection circuit 10 in this embodiment also does not affect the normal driving of the backlight chip 20 to light the LED light bar 30, and ensures the operational reliability of the LED light bar 30 and the backlight chip 20.
When the positive electrode and the negative electrode of the LED light bar 30 are short-circuited, the negative electrode of the LED light bar 30 instantaneously becomes a high voltage equal to the positive electrode of the LED, and the voltage of the LED control pin led_ic increases with the increase of the negative electrode voltage of the LED light bar 30 because the LED control pin led_ic is turned on with the negative electrode of the LED light bar 30. When the LED control pin led_ic increases, the voltage difference between the control terminal and the input terminal of the first switching device Q1 gradually decreases, and when the voltage difference between the control terminal and the input terminal of the first switching device Q1 decreases to the on voltage value of the first switching device Q1, the output terminal and the input terminal of the first switching device Q1 are disconnected. Before the first switching device Q1 is turned off, the voltage of the LED control pin led_ic is greater than the power VCC voltage of the backlight chip 20, that is, the anode voltage of the first diode D1 is greater than the cathode voltage, the first diode D1 is turned on, and the first diode D1 clamps the voltage of the LED control pin led_ic to the power VCC voltage of the backlight chip 20. When the first switching device Q1 is turned off, the voltage of the LED control pin led_ic is approximately equal to the voltage of the power VCC of the backlight chip 20. Therefore, after the short circuit occurs in the LED light bar 30, even if there is a delay in the turn-off response speed of the first switching device Q1, the voltage of the LED control pin led_ic can be clamped to the power VCC voltage of the backlight chip 20 through the first diode D1, so that the voltage of the LED control pin led_ic is ensured to be far less than the voltage specification of the built-in dimming MOS transistor, and the built-in dimming MOS transistor is protected from being damaged.
When the positive electrode and the negative electrode of the LED light bar 30 are short-circuited, the LED light bar 30 can generate larger transient current. When the voltage difference between the control terminal and the input terminal of the first switching device Q1 decreases as the voltage of the LED control pin led_ic increases, the on-resistance between the input terminal and the output terminal of the first switching device Q1 increases, thereby reducing the transient current generated by the short circuit. After the first diode D1 is conducted, the current flows from a low-impedance passage, namely, the passage of the first diode D1 can separate part of transient current, so that the transient current flowing in the LED control pin LED_IC is greatly reduced and is far smaller than the impact current specification of the built-in dimming MOS tube, and the built-in dimming MOS tube is protected from being damaged.
In an embodiment, referring to fig. 1, the first switching device Q1 is an N-type field effect transistor, a gate of the N-type field effect transistor is a control end of the first switching device Q1, a source of the N-type field effect transistor is an input end of the first switching device Q1, and a drain of the N-type field effect transistor is an output end of the first switching device Q1. The voltage difference between the gate and the source of the N-type field effect transistor is the driving voltage of the N-type field effect transistor. When the LED control pin LED_IC outputs a low-level signal, the driving voltage of the N-type field effect transistor is larger than the conducting voltage value of the N-type field effect transistor, and the N-type field effect transistor is conducted, so that the negative electrode of the LED lamp strip 30 is connected to the low-level signal output by the LED control pin LED_IC, and the LED lamp strip 30 is conducted to emit light. After the LED light bar 30 is shorted, the driving voltage of the N-type field effect transistor decreases along with the increase of the voltage of the control pin, when the driving voltage of the N-type field effect transistor decreases to the on voltage value, the N-type field effect transistor is turned off, and at this time, the driving voltage is equal to the difference between the power VCC voltage of the backlight chip 20 and the voltage of the LED control pin led_ic, so the voltage of the LED control pin led_ic is approximately equal to the power VCC voltage of the backlight chip 20, and the voltage of the LED control pin led_ic is far less than the voltage specification of the built-in dimming MOS transistor. Along with the reduction of the driving voltage of the N-type field effect transistor, the on-resistance of the N-type field effect transistor is continuously increased, so that the transient current generated when the LED light bar 30 is short-circuited is greatly reduced, and the current of the LED control pin LED_IC is far less than the impact current specification of the built-in dimming MOS transistor by matching with the shunting effect of the first diode D1.
It should be noted that, the first switching device Q1 may be a bipolar transistor in addition to a MOS transistor, where the MOS transistor and the bipolar transistor are used as switching devices commonly used in industry, and the cost advantage is obvious and the circuit structure is simple, and the consumed power is extremely low, so that the efficiency and standby power consumption of the power are not affected basically, and the method saves environmental protection.
In an embodiment, referring to fig. 1, the backlight chip protection circuit 10 further includes a first resistor R1, a first end of the first resistor R1 is used for being connected to the power VCC of the backlight chip 20, and a second end of the first resistor R1 is used for being connected to the control end of the first switching device Q1. For example, when the first switching device Q1 is an N-type field effect transistor, the voltage VCC of the power supply VCC of the backlight chip 20 is shunted by the first resistor R1 after passing through the first resistor R1 and then acts on the control terminal of the N-type field effect transistor. It can be understood that if the power VCC voltage of the backlight chip 20 is not split by the first resistor R1, the large current directly acts on the control terminal of the N-type fet, which is easily burned out. Therefore, the first resistor R1 can limit the current of the N-type field effect transistor, so that the working safety of the N-type field effect transistor is improved, and the circuit reliability is improved.
In an embodiment, referring to fig. 1, the backlight chip protection circuit 10 further includes a second resistor R2, a first end of the second resistor R2 is used to connect to the control end of the first switching device Q1, and a first end of the second resistor R2 is used to control the LED pin led_ic of the backlight chip 20. For example, when the first switching device Q1 adopts an N-type field effect transistor, the second resistor R2 may be regarded as a driving voltage clamping resistor of the N-type field effect transistor, and acts together with the first diode D1 to clamp the voltage of the LED control pin led_ic to the power VCC voltage of the backlight chip 20, so as to prevent the N-type field effect transistor from being damaged due to malfunction, ensure the working safety of the N-type field effect transistor, and improve the circuit reliability.
On the basis of the above embodiment, the present embodiment also provides a circuit board including the backlight chip protection circuit 10 described in the above embodiment. Illustratively, the circuit board includes a unitary board card or a plurality of splice cards, with the backlight chip protection circuit 10 disposed thereon. After the circuit board adopts the backlight chip protection circuit 10 described in the above embodiment, the built-in dimming MOS tube of the backlight chip 20 can be effectively protected from being damaged, and the security of the backlight board is improved.
On the basis of the above embodiments, fig. 2 is a schematic structural diagram of a backlight board according to an embodiment of the present utility model. As shown in fig. 2, the backlight board includes the backlight chip 20, the LED light bars 30, and the circuit board described in the above embodiments. The LED control pin LED_IC of the backlight chip 20 is connected with the backlight chip protection circuit 10 of the circuit board through a power supply, the cathode of the LED lamp strip 30 is connected with the backlight chip protection circuit 10 of the circuit board, and the anode of the LED lamp strip 30 is connected with the power supply VIN. The backlight board provided in this embodiment adds the backlight chip protection circuit 10 between the backlight chip 20 and the LED light bar 30, so as to clamp the voltage of the LED control pin led_ic near the power VCC voltage of the backlight chip 20 and reduce the current of the LED control pin led_ic when the LED light bar 30 is shorted by the backlight chip protection circuit 10, so as to ensure that the voltage and the current of the built-in dimming MOS tube are far smaller than the safety specification, protect the built-in dimming MOS tube of the backlight chip 20 from being damaged, and improve the safety of the backlight board.
In an embodiment, referring to fig. 2, the backlight panel further includes a second diode D2, an anode of the second diode D2 is connected to the power supply VIN, and a second end of the second diode D2 is connected to a cathode of the LED light bar 30. The power supply VIN is an ac power source, and the second diode D2 rectifies the power supply VIN, so that the rectified dc power acts on the LED light bar 30. In this embodiment, referring to fig. 2, the backlight panel further includes an electrolytic capacitor E1, a first end of the electrolytic capacitor E1 is connected to the cathode of the second diode D2 and the anode of the LED light bar 30, and a second end of the electrolytic capacitor E1 is grounded SGND. The electrolytic capacitor E1 can filter the alternating current passing through the second diode D2, so as to avoid the alternating current from affecting the work of the LDE light bar, and ensure the working reliability of the backlight plate.
In an embodiment, referring to fig. 2, the backlight panel further includes a first inductor L1, a first end of the first inductor L1 is connected to the power supply VIN, and a second end of the first inductor L1 is connected to an anode of the second diode D2. For example, as the boost energy storage inductor of the LED light bar 30, the first inductor L1 may boost the power supply VIN to reach the rated power range of the LED light bar 30. In this embodiment, referring to fig. 2, the backlight panel further includes a second switching device Q2, a control terminal of the second switching device Q2 is connected to a driving pin of the backlight chip 20, an input terminal of the second switching device Q2 is grounded to SGND, and an output terminal of the second switching device Q2 is connected to a second terminal of the first inductor L1. For example, the second switching device Q2 may also be an N-type field effect transistor, when the driving pin of the backlight chip 20 outputs a high level signal, the driving voltage of the N-type field effect transistor is greater than the on voltage value, the input end and the output end of the second switching device Q2 are turned on, at this time, the positive electrode of the LED light bar 30 is grounded SGND, and the LED light bar 30 is turned off to be in the off state. When the driving pin of the backlight chip 20 outputs a low-level signal, the driving voltage of the N-type field effect transistor is smaller than the conducting voltage value, the input end and the output end of the second switching device Q2 are disconnected, at this time, the anode of the LED light bar 30 is connected to the boosted power supply VIN, and the LED light bar 30 is turned on to be in a light-on state. The backlight chip 20 controls whether the power supply VIN supplies power to the LED lamp strip 30 through the driving pins, when the LED lamp strip 30 is short-circuited, the backlight chip 20 can cut off the power supply VIN to supply power to the LED lamp strip 30 through the driving pins, so that the LED lamp strip 30 is prevented from being kept in a short-circuited state for a long time, and the safety of the LED lamp strip 30 is ensured.
On the basis of the above embodiments, the present embodiment also provides a display device including the backlight described in the above embodiments. After the backlight plate described in the above embodiments is used in the display device, the backlight chip 20 or the backlight plate does not need to be replaced frequently, so that the service life of the display device is prolonged.
In summary, when the backlight chip protection circuit 10, the backlight board and the display device provided by the embodiment of the utility model are turned on, the LED control pin led_ic outputs a low-level signal, the input end and the output end of the first switching device Q1 are turned on, the negative electrode of the LED light bar 30 is connected to the low-level signal, the LED light bar 30 is turned on, and the LED light bar 30 emits light normally. When the LED light bar 30 is shorted, the negative electrode of the LED light bar 30 instantaneously becomes a high voltage as the positive electrode of the LED light bar 30, the voltage of the LED control pin led_ic increases along with the voltage rise of the negative electrode of the LED light bar 30, the voltage of the LED control pin led_ic increases to reduce the voltage difference between the control end and the input end of the first switching device Q1, and when the voltage difference between the control end and the input end of the first switching device Q1 is reduced to a preset voltage value, the input end and the output end of the first switching device Q1 are disconnected, at this time, the voltage of the LED control pin led_ic is approximately equal to the power VCC voltage of the backlight chip 20, and the power VCC voltage of the backlight chip 20 is far less than the voltage specification of the MOS transistor of the built-in dimming chip. As the voltage difference between the control terminal and the input terminal of the first switching device Q1 decreases, the on-resistance of the first switching device Q1 increases continuously, so as to greatly reduce the transient current when the LED light bar 30 is short-circuited. Before the input end and the output end of the first switching device Q1 are disconnected, the first diode D1 is turned on and splits part of transient current, so that the transient current is far smaller than the impact current specification of the built-in dimming MOS transistor, and after the first diode D1 is turned on, the voltage of the LED control pin led_ic is clamped at the power VCC voltage of the backlight chip 20. Through the technical means, the technical problem that the voltage and the current of the built-in dimming MOS tube of the backlight chip 20 exceed the safety specifications when the LED lamp strip 30 is in short circuit in the prior art is solved, the built-in dimming MOS tube of the backlight chip 20 is protected from being damaged, and the safety of the backlight chip 20 is improved.
The foregoing description is only of the preferred embodiments of the utility model and the technical principles employed. The present utility model is not limited to the specific embodiments described herein, but is capable of numerous modifications, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, while the utility model has been described in connection with the above embodiments, the utility model is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit of the utility model, the scope of which is set forth in the following claims.
Claims (11)
1. A backlight chip protection circuit, comprising a first switching device and a first diode, wherein:
the control end of the first switching device and the cathode of the first diode are used for being connected with a power supply of a backlight chip, the anode of the first diode and the input end of the first switching device are used for being connected with an LED control pin of the backlight chip, and the output end of the first switching device is used for being connected with the cathode of an LED lamp strip;
when the voltage difference between the control end and the input end of the first switching device is larger than a preset conducting voltage value, the input end and the output end of the first switching device are conducted.
2. The backlight chip protection circuit according to claim 1, wherein the first switching device is an N-type field effect transistor, a gate of the N-type field effect transistor is a control terminal of the first switching device, a source of the N-type field effect transistor is an input terminal of the first switching device, and a drain of the N-type field effect transistor is an output terminal of the first switching device.
3. The backlight chip protection circuit of claim 1, further comprising a first resistor, a first end of the first resistor being configured to be connected to a power supply of the backlight chip, and a second end of the first resistor being configured to be connected to a control end of the first switching device.
4. The backlight chip protection circuit of claim 1, further comprising a second resistor, a first end of the second resistor being used to connect to a control end of the first switching device, and a first end of the second resistor being used to control pins of LEDs of the backlight chip.
5. A circuit board comprising the backlight chip protection circuit according to any one of claims 1 to 4.
6. The backlight board is characterized by comprising a backlight chip, an LED lamp strip and the circuit board according to claim 5, wherein an LED control pin and a power supply of the backlight chip are connected with a backlight chip protection circuit of the circuit board, a negative electrode of the LED lamp strip is connected with the backlight chip protection circuit of the circuit board, and a positive electrode of the LED lamp strip is connected with a power supply.
7. The backlight of claim 6, further comprising a second diode, wherein an anode of the second diode is connected to the power supply, and a second end of the second diode is connected to a cathode of the LED light bar.
8. The backlight of claim 7, further comprising an electrolytic capacitor, wherein a first end of the electrolytic capacitor is connected to the cathode of the second diode and the anode of the LED light bar, and a second end of the electrolytic capacitor is grounded.
9. The backlight of claim 7, further comprising a first inductor, a first end of the first inductor being connected to the power supply, and a second end of the first inductor being connected to an anode of the second diode.
10. The backlight of claim 9, further comprising a second switching device, wherein a control terminal of the second switching device is connected to a driving pin of the backlight chip, an input terminal of the second switching device is grounded, and an output terminal of the second switching device is connected to a second terminal of the first inductor.
11. A display device comprising a backlight as claimed in any one of claims 6-10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320173512.2U CN219644153U (en) | 2023-01-16 | 2023-01-16 | Backlight chip protection circuit, circuit board, backlight board and display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320173512.2U CN219644153U (en) | 2023-01-16 | 2023-01-16 | Backlight chip protection circuit, circuit board, backlight board and display device |
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| Publication Number | Publication Date |
|---|---|
| CN219644153U true CN219644153U (en) | 2023-09-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320173512.2U Active CN219644153U (en) | 2023-01-16 | 2023-01-16 | Backlight chip protection circuit, circuit board, backlight board and display device |
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| Country | Link |
|---|---|
| CN (1) | CN219644153U (en) |
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2023
- 2023-01-16 CN CN202320173512.2U patent/CN219644153U/en active Active
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