LED driver chip and LED display

Abstract

The present invention discloses an LED driver chip and an LED display, comprising: a control unit for outputting a control signal; a shadow elimination unit coupled to the control unit for providing a shadow elimination voltage in response to the control signal; and at least one driving unit respectively coupled to the control unit for providing a driving signal in response to the control signal, wherein: the shadow elimination unit comprises at least one output terminal, and the at least one output terminal is coupled to the output terminal of the at least one driving unit correspondingly, and is used to alternately output the shadow elimination voltage and the driving signal. The LED driver chip and the LED display of the present invention avoid the problem of increased power consumption and volume of the driver chip caused by repeated setting of the shadow elimination circuit by setting the shadow elimination unit to replace the shadow elimination circuit in the driving unit in the prior art, thereby reducing the cost of the LED driver chip and the LED display.

Description

Technical Field

[0001] The present invention relates to the technical field of LED screen drive display, and in particular to an LED drive chip and an LED display. Background Art

[0002] In recent years, LED displays have been widely used in various fields as manufacturing technology matures. However, in traditional LED displays, since the parasitic capacitance of each row is charged when the LED emits light, the electricity has nowhere to be released after it is turned off, resulting in the release of light in the form of light, resulting in ghosting. Therefore, in the existing drive circuit, a ghosting potential is set in the drive circuit corresponding to each row. The setting of multiple ghosting potentials not only increases the power consumption of the drive chip, but also increases the complexity of the drive chip, hindering the further miniaturization of the drive chip.

[0003] Therefore, a new method for setting up a LED screen driver chip is needed to reduce the power consumption and volume of the existing LED screen driver chip. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide an LED driver chip and an LED display, so as to reduce the power consumption and volume of the LED driver chip.

[0005] According to one aspect of the present invention, there is provided an LED driver chip, comprising: a control unit for outputting a control signal; a shadow cancellation unit, coupled to the control unit, for providing a shadow cancellation voltage in response to the control signal; and at least one driving unit, respectively coupled to the control unit, for providing a driving signal in response to the control signal, wherein: the shadow cancellation unit comprises at least one output terminal, and the at least one output terminal is coupled correspondingly to the output terminal of the at least one driving unit, for alternately outputting the shadow cancellation voltage and the driving signal.

[0006] Optionally, the shadow elimination unit includes a buffer and at least one switch, and a conduction state of the at least one switch is responsive to the control signal.

[0007] Optionally, the control signal includes a third voltage, and the buffer receives the third voltage and outputs an image elimination voltage.

[0008] Optionally, the at least one switch is arranged corresponding to the at least one driving unit.

[0009] Optionally, the control signal includes a first voltage, the at least one driving unit includes a first MOS transistor, a gate of the first MOS transistor receives the first voltage, and is used to generate a current at a drain whose magnitude is responsive to the first voltage.

[0010] Optionally, it is characterized in that the at least one driving unit includes a second MOS tube, and the second MOS tube is coupled between the drain of the first MOS tube and the output end, and serves as a switch tube.

[0011] Optionally, the at least one switch and the second MOS transistor in the corresponding driving unit are turned on alternately.

[0012] Optionally, the at least one driving unit includes an amplifier, a positive input terminal of the amplifier is coupled to the drain of the first MOS tube, an output terminal is coupled to the gate of the second MOS tube, the control signal also includes a second voltage, and a negative input terminal of the amplifier receives the second voltage to adjust the drain voltage of the first MOS tube and the conduction state of the second MOS tube.

[0013] According to another aspect of the present invention, there is provided an LED display, comprising: an LED driving chip as described in any one of the above; and an LED display panel coupled to the output end of the at least one driving unit to receive the blanking voltage and the driving signal.

[0014] Optionally, the LED display panel is at least one of a sub-millimeter light emitting diode panel, a micro light emitting diode panel or a quantum dot light emitting diode.

[0015] The LED driver chip and LED display provided by the present invention are provided with a shadow elimination unit to realize driving of the LED display panel in a shadow elimination state. Specifically, since the specifications of the multiple light-emitting diodes in the LED display panel are the same and they are arranged in a uniform array, the parasitic capacitance of each row in the LED display panel is similar or even the same. Therefore, a shadow elimination unit can be used to provide the shadow elimination voltage required for each row, and a control unit is used to control the shadow elimination unit to output the shadow elimination voltage. The present invention uses an independent shadow elimination unit to provide the shadow elimination voltage, which avoids the need to set a shadow elimination circuit in the driving unit corresponding to each row in the prior art, reduces the power consumption of the LED driver chip, improves the integration of the chip, and is conducive to the miniaturization of the LED driver chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0017] Figure 1 A schematic block diagram showing the connection of an LED driver chip according to the prior art is shown;

[0018] Figure 2 Shows Figure 1 An example circuit structure diagram of a driving unit shown;

[0019] Figure 3A schematic block diagram showing the connection of an LED driver chip according to an embodiment of the present invention is shown;

[0020] Figure 4 Shows Figure 3 An example circuit structure diagram of the driving unit and the shadow elimination unit is shown. DETAILED DESCRIPTION

[0021] Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements or modules are represented by the same or similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale.

[0022] It should be understood that in the following description, a "circuit" may include a single or multiple combined hardware circuits, programmable circuits, state machine circuits, and / or elements capable of storing instructions executed by programmable circuits. When an element or circuit is said to be "connected to" another element or an element or circuit is said to be "connected between" two nodes, it may be directly coupled or connected to another element or there may be an intermediate element, and the connection between the elements may be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0023] At the same time, certain words are used in this patent specification and claims to refer to specific components. It should be understood by those skilled in the art that hardware manufacturers may use different terms to refer to the same component. This patent specification and claims do not use differences in names as a way to distinguish components, but rather use differences in components' functions as the criteria for distinction.

[0024] In addition, it should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the statement "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0025] The LED display panel uses a light-emitting diode as a light-emitting device. Specifically, the diode emits light when it is forward-conducting and does not emit light when it is reverse-blocked. However, due to the presence of parasitic capacitance at both ends of the LED, the parasitic capacitance is charged when the diode is forward-conducting, and when it is blocked, the parasitic capacitance will cause the diode to emit light, which is the ghosting phenomenon. Generally speaking, a ghosting part is set in the driving circuit of the LED display panel to provide a ghosting voltage to eliminate the ghosting phenomenon when the diode is reverse-blocked. However, each row in the LED display panel requires a corresponding driving circuit, and multiple repeated ghosting circuits increase the power consumption and volume of the driving chip.

[0026] Figure 1 A schematic block diagram of the connection between an LED driver chip and an LED display panel in the prior art is shown, wherein the LED driver chip includes a control unit and a plurality of driver units 1-n, wherein the control unit is coupled to the driver unit to provide a control signal, and the control signal is used to control the driver unit 1-n to output output signals OUT1-n in a preset order.

[0027] Figure 2 Shows Figure 1 The circuit structure diagram of the drive unit in Figure 2 In the illustrated embodiment, the shadow elimination circuit in the driving unit includes, for example, a buffer, and the driving circuit in the driving unit includes, for example, MOS tubes N1CH1, N2CH1, and an amplifier. Specifically, the buffer in the shadow elimination circuit receives an external voltage signal VB3, and the output end is coupled to the output end of the driving unit through a switch S, and the switch S responds to a control signal output by the control unit; the MOS tubes N1CH1 and N2CH1 in the driving circuit are connected in series, the drain of N1CH1 is coupled to the source of N2CH1, the source of N1CH1 is grounded, and the gate receives the external voltage signal VB1 to control the output current of the drain, the negative input end of the amplifier receives the external voltage signal VB2, and the positive input end and the output end are respectively coupled to the drain of N1CH1 and the gate of N2CH1; the drain of N2CH1 is coupled to the output end of the driving unit.

[0028] The driving unit in the prior art can output a blanking voltage or a forward conduction signal in response to a control signal. However, since a plurality of driving units are often required, the blanking circuit is repeatedly provided, which increases the volume and power consumption.

[0029] Figure 3A schematic block diagram of the connection between a driver chip and an LED display panel according to an embodiment of the present invention is shown. The driver chip outputs a plurality of output signals OUT1-n, and the LED display panel generates corresponding images in response to the output signals OUT1-n. The driver chip includes a control unit, an image elimination unit, and a driver unit 1-n. The control unit is coupled to the image elimination unit and the driver unit 1-n, respectively. The image elimination unit and the driver unit 1-n both respond to the control unit to generate an image elimination voltage VDD and a driving signal. It should be understood that the image elimination unit is coupled to the output end of the driver unit 1-n, respectively, so that the output end of the driver chip alternately outputs the driving signal and the image elimination voltage VDD. Specifically, the number of the driver units corresponds to the number of rows of light-emitting diodes in the LED display panel. For example, the number of the driver units and the number of rows of light-emitting diodes in the LED display panel are both n, and the driver unit is coupled to each row of diodes in a one-to-one correspondence.

[0030] The output signals OUT1-n may be different according to the control signal. Specifically, the output signals OUT1-n may be any one of the above-mentioned driving signals or the blanking voltage VDD.

[0031] Figure 4 A schematic diagram of the circuit connection of a driving unit and a shadow elimination unit in a driving chip according to some embodiments of the present invention is shown, wherein the shadow elimination unit, for example, includes a buffer and a plurality of switches S1-Sn. Specifically, the input end of the buffer is, for example, coupled to the control unit to receive a third voltage VB3, and the buffer is used to reduce voltage fluctuations to output a stable shadow elimination voltage VDD. The switches S1-Sn are respectively arranged between the output end of the buffer and the output end of the driving unit 1-n, and the conduction state of the switches S1-Sn is controlled by the control unit. Through the above arrangement, the control unit can control whether any output terminal of the driving chip outputs a shadow elimination voltage, and can also adjust the magnitude of the output shadow elimination voltage.

[0032] The driver chip of the present invention further comprises a plurality of driver units 1-n, and the first driver unit is used for the following description. It should be understood by those skilled in the art that the driver units in the driver chip have no sequence, and the sequence numbers here are only used to distinguish them.

[0033] In the embodiment of the present invention, the driving unit includes a first MOS transistor N1CH1, a second MOS transistor N2CH1 and a first amplifier AMP1, wherein N1CH1 and N2CH1 are sequentially connected in series between the output terminal and the ground, the drain of N1CH1 is electrically connected to the source of N2CH1, the source of N1CH1 is grounded, the drain of N2CH1 is connected to the output terminal, and the positive input terminal and the output terminal of the first amplifier AMP1 are respectively coupled to the drain of N1CH1 and the gate of N2CH1. N1CH1 is used as a voltage-controlled current source, and its gate receives a first voltage VB1, which is provided by a control unit, for example, and the drain output of N1CH1 is responsive to the current of the first voltage VB1. N2CH1 is used as a switch tube, and its conduction state responds to the output voltage of the first amplifier AMP1. The negative input terminal of the first amplifier AMP1 receives a second voltage VB2, which is provided by the control unit, for example, and the second voltage VB2 cooperates with the first amplifier AMP1 to control the drain voltage of N1CH1 and the conduction state of N2CH1, thereby controlling the driving signal output by the driving unit.

[0034] It should be understood that other driving units are similarly provided with MOS tubes N1CH2 - N1CHn, N2CH2 - N2CHn and amplifiers AMP2 - AMPn.

[0035] When the LED driver chip of the present invention starts to work, for example, the LED diode corresponding to the first driver unit needs to emit light, at this time, the control unit controls the switch S1 to be disconnected, and controls N1CH1 to output the drive current by outputting the first voltage VB1 and the second voltage VB2, and turns on N2CH1 to output the drive current as a drive signal; when the above-mentioned LED diode needs to stop emitting light, the control unit controls N2CH1 to be disconnected, and turns on the switch S1 to convert the output signal OUT1 into the blanking voltage VDD.

[0036] The present invention further provides an LED display, comprising the above-mentioned LED driving chip and an LED display panel, wherein the LED display panel receives the above-mentioned output signals OUT1-n.

[0037] It should be understood that the LED driver chip of the present invention has a wide range of applicability and can be used in different LED displays that require shadow elimination. Specifically, the above-mentioned LED display panel can be at least one of a sub-millimeter light-emitting diode panel, a micro-light-emitting diode panel or a quantum dot light-emitting diode.

[0038] According to the embodiments of the present invention, as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The scope of protection of the present invention shall be based on the scope defined by the claims of the present invention and their equivalents.

Claims

1. An LED driver chip, characterized in that: include: A control unit, used for outputting a control signal; A plurality of driving units are respectively coupled to the control unit, the plurality of driving units respectively comprising a first MOS tube and a second MOS tube, the second MOS tube is coupled between the drain of the first MOS tube and the output end of the corresponding driving unit, the first MOS tube generates a driving signal in response to the control signal, and the second MOS tube is used as a switch tube to output the driving signal; as well as a shadow elimination unit, coupled to the control unit to receive the control signal, the shadow elimination unit comprising a buffer and a plurality of switches, the output end of the buffer being coupled to one end of the plurality of switches, the other ends of the plurality of switches being respectively coupled to the output ends of the plurality of driving units, and the conduction states of the plurality of switches being controlled according to the control signal to output a shadow elimination voltage, The plurality of switches in the shadow elimination unit and the second MOS tube in the corresponding driving unit are turned on alternately, so that the shadow elimination voltage and the driving signal are output alternately when driving each row of LEDs of the LED display.

2. The LED driver chip according to claim 1, characterized in that: The control signal includes a third voltage, and the buffer receives the third voltage and outputs an image elimination voltage.

3. The LED driver chip according to claim 1, characterized in that: The control signal includes a first voltage, and the gate of the first MOS transistor receives the first voltage to generate a current at the drain whose magnitude is responsive to the first voltage.

4. The LED driver chip according to claim 3, characterized in that: The multiple driving units respectively include an amplifier, a positive input terminal of the amplifier is coupled to the drain of the first MOS tube, and an output terminal is coupled to the gate of the second MOS tube, the control signal also includes a second voltage, and a negative input terminal of the amplifier receives the second voltage to adjust the drain voltage of the first MOS tube and the conduction state of the second MOS tube.

5. An LED display, characterized in that: include: The LED driver chip according to any one of claims 1 to 4; The LED display panel is coupled to the output ends of the plurality of driving units to receive the blanking voltage and the driving signal.

6. The LED display according to claim 5, characterized in that: The LED display panel is at least one of a sub-millimeter light emitting diode panel, a micro light emitting diode panel or a quantum dot light emitting diode.

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