TWI832434B - Burn-proof pixel circuits, display devices and information processing devices - Google Patents

Abstract

A pixel circuit that can prevent burnout, which has: a plurality of OLED pixel circuit units, coupled between a common positive voltage connection terminal and a negative voltage source; and a current source, coupled between a positive voltage source and the common between positive voltage connections.

Description

Burn-proof pixel circuits, display devices and information processing devices

The present invention relates to an OLED pixel circuit, and in particular, to an OLED pixel circuit that can prevent burnout.

The current operating range of the OLED (organic light emitting diode; organic light emitting diode) pixel circuit is determined by the performance of the light emitting layer (EL) evaporated on the OLED element.

In order to prevent the OLED pixel circuit from being burned, some manufacturers will insert an additional transistor into the OLED pixel circuit to use this additional transistor when unexpected conditions occur (abnormal matching circuit setting operation, abnormal temperature or electrostatic attack). The channel impedance of the crystal provides a current limiting effect to prevent the OLED pixel circuit from being burned.

In addition, some manufacturers do not install the extra transistor but use algorithms to prevent the OLED pixel circuit from generating abnormally large currents. This type of algorithm mainly uses the algorithm to adjust the pixel data voltage to reduce the overall current when maximum brightness occurs. However, this type of algorithm can generally only deal with normal working conditions. If it is an unexpected situation (abnormal matching circuit setting operation, abnormal temperature or electrostatic attack), it cannot provide protection.

In order to solve the above problems, there is an urgent need in this field for a novel pixel circuit that can prevent burnout.

An object of the present invention is to disclose a pixel circuit that can prevent burnout, which can be provided by disposing a current source circuit between a positive voltage source and a common positive voltage connection end of a plurality of OLED pixel circuit units of the pixel circuit. An over-current protection prevents an abnormally large current from being generated when any of the OLED pixel circuit units is short-circuited.

Another object of the present invention is to disclose a display device that can provide an over-current protection function through the aforementioned pixel circuit that can prevent burnout.

Another object of the present invention is to disclose an information processing device that can provide an over-current protection function through the aforementioned pixel circuit that can prevent burnout.

In order to achieve the above purpose, a pixel circuit that can prevent burning is proposed, which has: A plurality of OLED pixel circuit units are coupled between a common positive voltage connection terminal and a negative voltage source; and A current source is coupled between a positive voltage source and the common positive voltage connection terminal.

In one embodiment, the current source has a rated output current value to provide a plurality of driving currents required by the plurality of OLED pixel circuit units. The driving currents are each determined by a pixel voltage and the sum of the driving currents is less than the rated output current value. Output current value.

In one embodiment, when any one of the OLED pixel circuit units is short-circuited, the rated output current value will cause the driving current flowing through the unit to be less than the maximum forward current of one of the OLED elements of the unit. .

In one embodiment, the current source is provided by a current mirror circuit.

To achieve the above object, the present invention further proposes a display device, which has a pixel array and a driving circuit for driving the pixel array. The pixel array includes a plurality of pixel circuits that can prevent burnout, and each of them should have a pixel circuit that can prevent burnout. The pixel circuit has: A plurality of OLED pixel circuit units are coupled between a common positive voltage connection terminal and a negative voltage source; and A current source is coupled between a positive voltage source and the common positive voltage connection terminal.

In one embodiment, the current source has a rated output current value to provide a plurality of driving currents required by the plurality of OLED pixel circuit units, and the driving currents are each determined by a pixel voltage provided by the driving circuit. And the sum is less than the rated output current value.

In one embodiment, when any one of the OLED pixel circuit units is short-circuited, the rated output current value will cause the driving current flowing through the unit to be less than the maximum forward current of one of the OLED elements of the unit. .

In one embodiment, the current source is provided by a current mirror circuit.

To achieve the above object, the present invention further proposes an information processing device, which has a central processing unit and the aforementioned display device, wherein the central processing unit is used to communicate with the display device.

In possible embodiments, the information processing device may be a smart handheld device, a portable computer, a wearable device, a vehicle-mounted computer or an access control system.

In order to enable the review committee to further understand the structure, characteristics and purpose of the present invention, drawings and detailed descriptions of preferred embodiments are attached as follows.

Please refer to FIG. 1 , which illustrates a circuit diagram of an embodiment of a burn-proof pixel circuit of the present invention. As shown in FIG. 1 , a burn-proof pixel circuit 100 has a plurality of OLED pixel circuit units 110 and a current source 120 .

The OLED pixel circuit units 110 are coupled between a common positive voltage connection terminal A and a negative voltage source VSS. Each OLED pixel circuit unit 110 has a voltage-to-current circuit 111, an OLED element 112 and an Switch 113, in which the voltage-to-current circuit 111 is used to determine a driving current of the OLED element 112 according to a pixel voltage V _Pj , j = 1 to N, N is an integer greater than 1; the OLED element 112 is connected to the voltage-to-current circuit 111 is stacked to receive the driving current; and the switch 113 is used to reset the voltage across the OLED element 112 to zero to provide a shadow elimination effect.

The current source 120 is coupled between a positive voltage source VDD and the common positive voltage connection terminal A, and has a rated output current value to provide the driving current required by the OLED pixel circuit units 110, wherein the rated output The current value must be greater than the sum of the driving currents to ensure that the OLED pixel circuit units 110 can operate normally.

In addition, in order to prevent any OLED pixel circuit unit 110 from generating an abnormally large current, the rated output current value must ensure that when any of the OLED pixel circuit units 110 is short-circuited, the current flowing through the unit does not exceed its OLED The maximum forward current of element 112. For example, assuming that the OLED element 112 of the first OLED pixel circuit unit 110 is short-circuited, it will cause a large current, causing the rated output current value of the current source 120 to be unable to meet the driving current required by these OLED pixel circuit units 110 , in this case, the voltage of the common positive voltage connection terminal A will drop downward to reduce the current flowing through the first OLED pixel circuit unit 110, thereby avoiding the current flowing through the OLED element 112 of the first OLED pixel circuit unit 110. The current exceeds its maximum forward current. In addition, when the voltage-to-current circuit 111 or the switch 113 is short-circuited due to unexpected circumstances (abnormal matching circuit setting operation, abnormal temperature or electrostatic attack), the rated output current value of the current source 120 can also exert an over-current protection effect to avoid Burn out the voltage-to-current circuit 111 or switch 113.

Alternatively, the current source 120 may be provided by a current mirror circuit. Since the current mirror circuit is a conventional technology, it will not be described in detail here.

According to the above description, the present invention provides a display device. Please refer to FIG. 2 , which illustrates a block diagram of a display device according to an embodiment of the present invention. As shown in FIG. 2 , a display device 200 has a pixel array 210 and a driving circuit 220 for driving the pixel array 210 . The pixel array 210 includes a plurality of pixel circuit driving circuits 211 that can prevent burnout and can prevent burnout. The pixel circuit driving circuit 211 is implemented by the pixel circuit 100 that can prevent burning.

According to the above description, the present invention further provides an information processing device. Please refer to FIG. 3 , which illustrates a block diagram of an embodiment of the information processing device of the present invention. As shown in FIG. 3 , an information processing device 300 has a central processing unit 310 and a display device 320 , wherein the display device 320 is implemented by the display device 200 , and the central processing unit 310 is used to communicate with the display device 320 .

Through the design disclosed above, the present invention has the following advantages: 1. The burn-proof pixel circuit of the present invention can provide an over-current protection by disposing a current source circuit between a positive voltage source and a common positive voltage connection terminal of multiple OLED pixel circuit units of the pixel circuit. This prevents abnormally large current from being generated when any of the OLED pixel circuit units is short-circuited. 2. The display device of the present invention can provide an over-current protection function through the aforementioned pixel circuit that can prevent burning. 3. The information processing device of the present invention can provide an over-current protection function through the aforementioned pixel circuit that can prevent burning.

What is disclosed in this case is a preferred embodiment. Any partial changes or modifications derived from the technical ideas of this case and easily inferred by those familiar with the art will not deviate from the scope of the patent rights of this case.

To sum up, regardless of the purpose, means and effects of this case, it shows that it is completely different from the conventional technology, and that the invention is practical first, and indeed meets the patent requirements for inventions. I sincerely ask the review committee to take a clear look and grant the patent as soon as possible for your benefit. Society is a prayer for the Supreme Being.

100: Pixel circuit that can prevent burnout 110:OLED pixel circuit unit 111: Voltage to current circuit 112:OLED components 113:switch 120:Current source 200:Display device 210: Pixel array 211: Pixel circuit driving circuit that can prevent burnout 220: Drive circuit 300:Information processing device 310:Central processing unit 320:Display device

FIG. 1 is a circuit diagram of an embodiment of a burn-proof pixel circuit of the present invention. FIG. 2 is a block diagram of a display device according to an embodiment of the present invention. FIG. 3 is a block diagram of an embodiment of the information processing device of the present invention.

100: Pixel circuit that can prevent burnout

110:OLED pixel circuit unit

111: Voltage to current circuit

112:OLED components

113: switch

120:Current source

Claims (6)

A pixel circuit that can prevent burnout, which has: a plurality of OLED pixel circuit units, coupled between a common positive voltage connection terminal and a negative voltage source; and a current source, coupled between a positive voltage source and the common between the positive voltage connection terminals; wherein, the current source has a rated output current value to provide a plurality of driving currents required by the plurality of OLED pixel circuit units. The driving currents are each determined by a pixel voltage and the sum of is less than the rated output current value; and when any unit among the OLED pixel circuit units is short-circuited, the rated output current value will cause the driving current flowing through the unit to be less than the maximum positive voltage of one of the OLED elements of the unit. towards current. In the pixel circuit capable of preventing burnout as described in item 1 of the patent application, the current source is provided by a current mirror circuit. A display device having a pixel array and a drive circuit for driving the pixel array. The pixel array includes a plurality of burn-proof pixel circuits, and each of the burn-proof pixel circuits has: a plurality of OLED pixel circuits. a unit coupled between a common positive voltage connection terminal and a negative voltage source; and a current source coupled between a positive voltage source and the common positive voltage connection terminal; wherein the current source has a rated output The current value is to provide a plurality of driving currents required by the plurality of OLED pixel circuit units. The driving currents are each determined by a pixel voltage provided by the driving circuit and the sum thereof is less than the rated output current value; and when the Any one of these OLED pixel circuit units When a short circuit occurs, the rated output current value will cause the driving current flowing through the unit to be less than the maximum forward current of one of the OLED elements of the unit. For the display device described in Item 3 of the patent application, the current source is provided by a current mirror circuit. An information processing device having a central processing unit and a display device as described in any one of items 3 to 4 of the patent application, wherein the central processing unit is used to communicate with the display device. The information processing device described in item 5 of the patent application is an electronic device selected from a group consisting of a smart handheld device, a portable computer, a wearable device, a vehicle-mounted computer and an access control system. .

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