LED backlight driving chip and BV protection method of driving pin

Abstract

The invention discloses an LED (Light Emitting Diode) backlight driving chip. The LED backlight driving chip comprises an LED pin, a high-voltage MOS (Metal Oxide Semiconductor) switch tube M1 and a driving operational circuit, the high-voltage MOS switch tube is an NMOS (N-channel Metal Oxide Semiconductor) or PMOS (P-channel Metal Oxide Semiconductor) switch tube, a drain electrode of the NMOS or PMOS switch tube is connected with the LED pin, a grid electrode of the NMOS or PMOS switch tube is controlled by a PWM (Pulse Width Modulation) signal, and the NMOS or PMOS switch tube is controlled to be switched on or switched off by the PWM signal; the source electrode of the NMOS or PMOS switch tube is connected with the driving operation circuit; the LED backlight driving chip further comprises a low-voltage ESD unit, and the low-voltage ESD unit is connected to the two ends of the operational circuit in parallel. According to the other mode, the low-voltage ESD units connected in series are connected between the LED pins and the ground or the power source, and the traditional high-voltage ESD units are replaced.

Description

Technical Field

[0001] The present invention relates to the technical field of LED backlight, and in particular to a BV protection method for an LED backlight driver chip and a driver pin. Background Art

[0002] Liquid crystal display (LCD) is the largest screen display application in modern display panels. The liquid crystal material used in LCD panels cannot emit light by itself and needs to be provided by a backlight source. LED backlight sources have the advantages of energy saving, environmental protection, and high performance and are widely used in LCD display panels. The performance of LED backlight driver chips is crucial to LCD display panels.

[0003] like Figure 1 As shown, the LED backlight driver chip in the prior art includes: LED pin, high-voltage MOS switch tube M1 and driving operation circuit, wherein: LED pin is used to connect LED light string, when LED light string is composed of multiple LED lamp beads connected in series, the voltage on LED pin is usually high, for example, 40V. The driving operation circuit is generally a low-voltage device to ensure operation speed and accuracy.

[0004] The ESD (Electro-Static discharge) unit in the prior art is generally set between the LED pin and the ground. Since the LED pin is in a high-voltage state, the corresponding ESD unit also needs to use a high-voltage device. The ESD unit is a structure in which a high-voltage MOS is connected to form a GGNMOS or a triode is connected to form a diode. The ESD unit is connected between the LED pin and GND to protect the device connected in parallel with it. When the ESD current comes, the snapback of the ESD device is used to quickly conduct and discharge. In this circuit structure, the breakdown voltage (BV) on the LED pin is actually determined by the breakdown voltage of the ESD device. This is because the switch tube M1 and the driving operation circuit are connected in series, and the sum of their BVs is greater than the BV of the ESD device.

[0005] It can be seen that a new LED backlight driver chip is needed in the art, and the new LED backlight driver chip can more effectively improve the breakdown voltage performance of the LED pins. Summary of the invention

[0006] The present invention provides an LED backlight driver chip. The LED backlight driver chip improves the breakdown voltage of the LED pin by changing the ESD unit setting of the LED pin of the chip, thereby achieving the effect of improving the breakdown voltage performance of the LED pin.

[0007] Based on the above technical purpose, the present invention provides an LED backlight driver chip, which includes: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit;

[0008] The high-voltage MOS switch tube is an NMOS switch tube, the drain of the NMOS switch tube is connected to the LED pin, the gate of the NMOS switch tube is controlled by a PWM signal, and the PWM signal controls the NMOS switch tube to be turned on or off; the source of the NMOS switch tube is connected to the driving operation circuit;

[0009] The LED backlight driving chip further comprises a low voltage ESD unit, and the low voltage ESD unit is connected in parallel to two ends of the driving operation circuit.

[0010] The present invention also provides another LED backlight driver chip, an LED backlight driver chip, the LED backlight driver chip comprises: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit;

[0011] The high-voltage MOS switch tube is a PMOS switch tube, the drain of the PMOS switch tube is connected to the LED pin, the gate of the PMOS switch tube is controlled by a PWM signal, and the PWM signal controls the PMOS switch tube to be turned on or off; the source of the PMOS switch tube is connected to the driving operation circuit;

[0012] The LED backlight driving chip further comprises a low voltage ESD unit, and the low voltage ESD unit is connected in parallel to two ends of the driving operation circuit.

[0013] The present invention also provides another LED backlight driver chip, an LED backlight driver chip, the LED backlight driver chip comprises: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit;

[0014] The high-voltage MOS switch tube is an NMOS switch tube, the drain of the NMOS switch tube is connected to the LED pin, the gate of the NMOS switch tube is controlled by a PWM signal, and the PWM signal controls the NMOS switch tube to be turned on or off; the source of the NMOS switch tube is connected to the driving operation circuit;

[0015] The LED backlight driving chip further includes a plurality of low-voltage ESD units, which are connected in series, and the plurality of low-voltage ESD units connected in series are connected in parallel between the LED pins and the ground.

[0016] The present invention also provides another LED backlight driver chip, an LED backlight driver chip, the LED backlight driver chip comprises: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit;

[0017] The high-voltage MOS switch tube is a PMOS switch tube, the drain of the PMOS switch tube is connected to the LED pin, the gate of the PMOS switch tube is controlled by a PWM signal, and the PWM signal controls the PMOS switch tube to be turned on or off; the source of the PMOS switch tube is connected to the driving operation circuit;

[0018] The LED backlight driving chip further includes a plurality of low-voltage ESD units, which are connected in series, and the plurality of low-voltage ESD units connected in series are connected in parallel between the LED pins and an external power source.

[0019] Compared with the prior art, one or more embodiments of the present invention may have the following advantages:

[0020] The LED backlight driver chip of the present invention improves the breakdown voltage of the LED pin by changing the ESD unit setting of the chip LED pin, thereby achieving the effect of improving the breakdown voltage performance of the LED pin.

[0021] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a schematic diagram of the circuit structure of an LED backlight driver chip in the prior art;

[0024] Figure 2 is a schematic diagram of the circuit structure of the LED backlight driver chip of the first embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of the circuit structure of the LED backlight driver chip of the second embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of the circuit structure of the LED backlight driver chip of the third embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of the circuit structure of the LED backlight driving chip according to the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings.

[0029] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not indicate that the present invention necessarily has the first element, component, region, layer or part.

[0030] Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used here for convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientation shown in the figure, the spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, then the elements or features described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0031] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0032] Example 1

[0033] like Figure 2 As shown, the LED backlight driver chip of this embodiment includes: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit.

[0034] The high-voltage MOS switch tube is an NMOS switch tube, the drain of the NMOS switch tube is connected to the LED pin, the gate of the NMOS switch tube is controlled by a PWM signal, and the PWM signal controls the NMOS switch tube to be turned on or off; the source of the NMOS switch tube is connected to the driving operation circuit.

[0035] The LED backlight driving chip further includes a low-voltage ESD unit, which is connected in parallel between the source of the NMOS switch tube and the ground.

[0036] In this embodiment, through integrated circuit design, the high-voltage MOS switch tube is designed to achieve self-ESD protection. When ESD charge comes, the high-voltage MOS switch tube can self-conduct to discharge the ESD current to the high potential end of the driving operation circuit, and the low-voltage ESD unit parallel to the driving operation circuit will be triggered to conduct, discharging the ESD current to GND, eliminating the high-voltage ESD protection module from the LED pin to the ground end. The design feature of the high-voltage MOS switch tube is that the high-voltage MOS switch tube can use an LDMOS switch tube with multiple P buried layers, and the LDMOS switch tube with multiple P-doped buried layers includes a first P-doped buried layer at the silicon dioxide layer of the LDMOS, and the first P-doped buried layer is used to form a high electric field at the junction between the silicon dioxide layer of the LDMOS and the N-type drift region to reduce the on-resistance of the LDMOS tube, so as to facilitate the rapid release of ESD charge. At the same time, a second P-doped buried layer and a third P-doped buried layer with different doping concentrations and lengths are arranged in the N-type drift region of the LDMOS switch tube, and the ends of the second P-doped buried layer and the third P-doped buried layer can generate a high electric field, thereby having an obvious depletion effect, thereby further reducing the on-resistance of the LDMOS tube.

[0037] Alternatively, in this embodiment, a capacitor may be connected across the gate and drain of the high-voltage MOS switch tube to achieve the purpose of quickly releasing the ESD charge.

[0038] In this embodiment, since the high-voltage ESD unit in the prior art is omitted, the breakdown voltage of the LED pin is determined by the breakdown voltage of the high-voltage MOS switch tube and the equivalent breakdown voltage of the low-voltage ESD unit in parallel with the driving operation circuit. Therefore, compared with the breakdown voltage of the high-voltage ESD unit in the prior art, the breakdown voltage of the LED pin is significantly improved.

[0039] Example 2

[0040] like Figure 3 As shown, the LED backlight driver chip of this embodiment includes: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit.

[0041] The high-voltage MOS switch tube is a PMOS switch tube, the drain of the PMOS switch tube is connected to the LED pin, the gate of the PMOS switch tube is controlled by a PWM signal, and the PWM signal controls the PMOS switch tube to be turned on or off; the source of the PMOS switch tube is connected to the drive operation circuit.

[0042] The LED backlight driving chip further comprises a low voltage ESD unit, and the low voltage ESD unit is connected in parallel to two ends of the driving operation circuit.

[0043] In this embodiment, through integrated circuit design, the high-voltage MOS switch tube is designed to achieve self-ESD protection. When ESD charge comes, the high-voltage MOS switch tube can self-conduct to discharge the ESD current to the high potential end of the driving operation circuit, and the low-voltage ESD unit parallel to the driving operation circuit will be triggered to conduct and discharge the ESD current to the external power supply, eliminating the high-voltage ESD protection module from the LED pin to the external power supply. The design of the high-voltage MOS switch tube is the same as that of the aforementioned embodiment 1.

[0044] In this embodiment, since the high-voltage ESD unit in the prior art is omitted, the breakdown voltage of the LED pin is determined by the breakdown voltage of the high-voltage MOS switch tube and the equivalent breakdown voltage of the low-voltage ESD unit in parallel with the driving operation circuit. Therefore, compared with the breakdown voltage of the high-voltage ESD unit in the prior art, the breakdown voltage of the LED pin is significantly improved.

[0045] Example 3

[0046] like Figure 4 As shown, the LED backlight driver chip of this embodiment includes: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit.

[0047] The high-voltage MOS switch tube is an NMOS switch tube, the drain of the NMOS switch tube is connected to the LED pin, the gate of the NMOS switch tube is controlled by a PWM signal, and the PWM signal controls the NMOS switch tube to be turned on or off; the source of the NMOS switch tube is connected to the driving operation circuit.

[0048] The LED backlight driving chip further includes a plurality of low-voltage ESD units, which are connected in series, and the plurality of low-voltage ESD units connected in series are connected in parallel between the LED pins and the ground.

[0049] In this embodiment, a high-voltage ESD unit in the prior art is replaced with multiple low-voltage ESD units connected in series, so that the breakdown voltage of the LED pin is converted to be determined by the sum of the breakdown voltages of the multiple low-voltage ESD units, and the sum of the breakdown voltages of the multiple low-voltage ESD units connected in series is also greater than the breakdown voltage of the high-voltage ESD unit in the prior art, thereby significantly improving the breakdown voltage of the LED pin.

[0050] Example 4

[0051] like Figure 5 As shown, the LED backlight driver chip of this embodiment includes: an LED pin, a high-voltage MOS switch tube M1 and a driving operation circuit.

[0052] The high-voltage MOS switch tube is a PMOS switch tube, the drain of the PMOS switch tube is connected to the LED pin, the gate of the PMOS switch tube is controlled by a PWM signal, and the PWM signal controls the PMOS switch tube to be turned on or off; the source of the PMOS switch tube is connected to the drive operation circuit.

[0053] The LED backlight driving chip further includes a plurality of low-voltage ESD units, which are connected in series, and the plurality of low-voltage ESD units connected in series are connected in parallel between the LED pins and an external power source.

[0054] In this embodiment, a high-voltage ESD unit in the prior art is replaced with multiple low-voltage ESD units connected in series, so that the breakdown voltage of the LED pin is converted to be determined by the sum of the breakdown voltages of the multiple low-voltage ESD units, and the sum of the breakdown voltages of the multiple low-voltage ESD units connected in series is also greater than the breakdown voltage of the high-voltage ESD unit in the prior art, thereby significantly improving the breakdown voltage of the LED pin.

[0055] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An LED backlight driver chip, characterized in that: The LED backlight driver chip includes: LED pins, a high-voltage MOS switch tube M1 and a driving operation circuit; The high-voltage MOS switch tube is an NMOS switch tube, the drain of the NMOS switch tube is connected to the LED pin, the gate of the NMOS switch tube is controlled by a PWM signal, and the PWM signal controls the NMOS switch tube to be turned on or off; the source of the NMOS switch tube is connected to the driving operation circuit; The LED backlight driving chip further comprises a low voltage ESD unit, and the low voltage ESD unit is connected in parallel to two ends of the driving operation circuit.

2. An LED backlight driver chip, characterized in that: The LED backlight driver chip includes: LED pins, high-voltage MOS switch tube M1 and a driving operation circuit; The high-voltage MOS switch tube is a PMOS switch tube, the drain of the PMOS switch tube is connected to the LED pin, the gate of the PMOS switch tube is controlled by a PWM signal, and the PWM signal controls the PMOS switch tube to be turned on or off; the source of the PMOS switch tube is connected to the driving operation circuit; The LED backlight driving chip further comprises a low voltage ESD unit, and the low voltage ESD unit is connected in parallel to two ends of the driving operation circuit.

3. An LED backlight driver chip, characterized in that: The LED backlight driver chip includes: LED pins, high-voltage MOS switch tube M1 and a driving operation circuit; The high-voltage MOS switch tube is an NMOS switch tube, the drain of the NMOS switch tube is connected to the LED pin, the gate of the NMOS switch tube is controlled by a PWM signal, and the PWM signal controls the NMOS switch tube to be turned on or off; the source of the NMOS switch tube is connected to the driving operation circuit; The LED backlight driving chip further includes a plurality of low-voltage ESD units, which are connected in series, and the plurality of low-voltage ESD units connected in series are connected in parallel between the LED pins and the ground.

4. An LED backlight driver chip, characterized in that: The LED backlight driver chip includes: LED pins, high-voltage MOS switch tube M1 and a driving operation circuit; The high-voltage MOS switch tube is a PMOS switch tube, the drain of the PMOS switch tube is connected to the LED pin, the gate of the PMOS switch tube is controlled by a PWM signal, and the PWM signal controls the PMOS switch tube to be turned on or off; the source of the PMOS switch tube is connected to the driving operation circuit; The LED backlight driving chip further includes a plurality of low-voltage ESD units, which are connected in series, and the plurality of low-voltage ESD units connected in series are connected in parallel between the LED pins and an external power source.

5. An LED backlight panel, wherein the LED backlight panel uses the LED backlight driver chip according to any one of claims 1 to 4 to drive LED light-emitting elements to emit light.

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