TWI849991B - AMOLED pixel compensation circuit, OLED display device and information processing device - Google Patents

Abstract

An AMOLED pixel compensation circuit has a switch circuit, a PMOS transistor, a capacitor combination and an OLED element. The source of the PMOS transistor is coupled to a DC supply voltage, and the cathode of the OLED element is coupled to a negative voltage. The switch circuit is used to execute a switch operation procedure to drive the PMOS transistor to generate a driving current so that the OLED element generates a brightness, and the switch operation procedure includes: the switch circuit forms a first configuration to couple a reference voltage to the gate voltage of the PMOS transistor and the anode voltage of the OLED element; the switch circuit forms a second configuration. The switch circuit forms a second configuration so that the PMOS transistor and the capacitor combination are connected in series to form a circuit between a common voltage and the DC supply voltage to collect the threshold voltage of the PMOS transistor; the switch circuit forms a third configuration so that one end of the capacitor combination is coupled to a data voltage so that the components of the voltage presented at the other end include the threshold voltage and the data voltage; and the switch circuit forms a fourth configuration so that the PMOS transistor and the OLED element are connected in series to generate the driving current, wherein the driving current is determined by the difference between the DC supply voltage and the voltage at the other end of the capacitor circuit.

Description

AMOLED pixel compensation circuit, OLED display device and information processing device

The present invention relates to the field of integrated circuits, and more particularly to an AMOLED pixel compensation circuit.

Each pixel of a general AMOLED (active mode organic light emitting diode) display module is composed of a pixel circuit, which includes an OLED unit and a transistor circuit for generating a driving current to drive the OLED (organic light emitting diode) unit. The transistor circuit generally includes a plurality of transistors and a storage capacitor, such as a 7T1C (seven PMOS transistors and a storage capacitor) structure, and generates a certain current according to the display data voltage stored in the storage capacitor, and controls the output time of the certain current according to a pulse modulation signal to determine the equivalent value of the driving current, thereby driving the OLED unit to present a predetermined brightness.

However, due to process variations, the transistors in the pixel circuits may have uneven threshold voltages, resulting in uneven display brightness of each pixel and causing Mura (mura) on the display screen.

In addition, to increase the battery life of mobile devices, when the displayed image is a static image, the general AMOLED display module will reduce the display scan refresh rate to save power. However, when the display scan refresh rate is reduced, the transistor leakage current in the transistor circuit will cause the storage voltage of the storage capacitor to drop, thereby affecting the display brightness of the OLED unit.

To solve the above problems, a novel AMOLED pixel compensation circuit architecture is urgently needed in the art.

One purpose of the present invention is to provide an AMOLED pixel compensation circuit, which can quickly equalize the source-gate voltage of the current source transistor of each OLED pixel in the process of displaying a frame, thereby minimizing the short-term afterimage caused by the hysteresis voltage of the source-gate parasitic capacitance of the current source transistor on the display image.

Another object of the present invention is to provide an AMOLED pixel compensation circuit that can compensate the threshold voltage of a current source transistor to minimize display unevenness and Mura caused by process deviation and voltage drop of a supply voltage.

Another object of the present invention is to disclose an AMOLED pixel compensation circuit that can extend the holding time of the driving voltage to support a low screen refresh rate.

Another object of the present invention is to disclose an OLED display device which can minimize the short-term afterimage of the display screen by using the aforementioned AMOLED pixel compensation circuit.

Another object of the present invention is to disclose an OLED display device, which can minimize display unevenness and Mura caused by process deviation and voltage drop of supply voltage through the aforementioned AMOLED pixel compensation circuit, and prolong the holding time of driving voltage to support low screen refresh rate.

Another object of the present invention is to disclose an OLED display device which can provide a screen display effect with uniform brightness by using the aforementioned AMOLED pixel compensation circuit.

Another object of the present invention is to disclose an information processing device that can optimize display effects and support low picture refresh rates by using the aforementioned AMOLED pixel compensation circuit.

To achieve the above-mentioned purpose, an AMOLED pixel compensation circuit is proposed, which has a switching circuit, a PMOS transistor, a capacitor combination and an OLED element, the source of the PMOS transistor is coupled to a DC supply voltage, the cathode of the OLED element is coupled to a negative voltage, the switching circuit is used to perform a switching operation procedure to drive the PMOS transistor to generate a driving current so that the OLED element generates a brightness, and the switching operation procedure includes: The switching circuit forms a first configuration to couple a reference voltage to the gate voltage of the PMOS transistor and the anode voltage of the OLED element; The switch circuit forms a second configuration so that the PMOS transistor and the capacitor combination are connected in series between a common voltage and the DC supply voltage to collect the threshold voltage of the PMOS transistor; The switch circuit forms a third configuration so that one end of the capacitor combination is coupled to a data voltage so that the voltage presented at the other end includes the threshold voltage and the data voltage; and The switch circuit forms a fourth configuration so that the PMOS transistor and the OLED element are connected in series to generate the driving current, wherein the driving current is determined by the difference between the DC supply voltage and the voltage at the other end of the capacitor circuit.

In one embodiment, the switch circuit and the PMOS transistor are fabricated using a low temperature polycrystalline oxide process.

In one embodiment, any transistor in the switch circuit is a transistor selected from the group consisting of PMOS transistors, NMOS transistors and CMOS transistors.

To achieve the aforementioned object, the present invention further provides an OLED display device having an AMOLED panel. The AMOLED panel has the AMOLED pixel compensation circuit as described above.

To achieve the aforementioned object, the present invention further provides an information processing device having a central processing unit and the aforementioned OLED display device, wherein the central processing unit is used to communicate with the OLED display device.

In possible embodiments, the information processing device may be a portable computer, a smart phone or a car computer.

In order to enable the review committee to further understand the structure, features, purpose, and advantages of this creation, the following are attached with diagrams and detailed descriptions of the preferred specific implementation examples.

The principle of the present invention is:

(i) using a switch circuit to uniformize the source-gate voltage of the current source transistor of each OLED pixel during the initialization period of displaying a frame of picture to minimize the difference in the hysteresis voltage of the source-gate parasitic capacitance of each current source transistor, thereby effectively reducing the short-term afterimage phenomenon of the displayed picture;

(ii) using the switch circuit to collect a linear combination voltage including a positive supply voltage, a data voltage and a threshold voltage of a current source transistor, and pre-storing the linear combination voltage in a storage capacitor;

(iii) using the switch circuit to drive the voltage of the storage capacitor to drive the current source transistor to generate a driving current that is independent of the positive supply voltage and the threshold voltage; and

(iv) A switch circuit manufactured using an oxide semiconductor process provides a low leakage current to extend the voltage holding time of the driving voltage.

Accordingly, the present invention can effectively reduce the short-term afterimage phenomenon of the display screen, minimize the influence of the threshold voltage and the positive supply voltage on the driving current, thereby optimizing the display effect of the OLED panel, and can support a low screen refresh rate.

Please refer to FIG. 1, which shows a circuit diagram of an embodiment of the AMOLED pixel compensation circuit of the present invention. As shown in FIG. 1, an AMOLED pixel compensation circuit 100 has a first switch 111, a second switch 112, a third switch 113, a fourth switch 114, a fifth switch 115, a PMOS transistor 120, a conduction time modulation switch 121, a first capacitor 131, a second capacitor 132 and an OLED element 140, wherein the PMOS transistor 120 and the switches can be manufactured by a LTPO (low temperature polycrystalline oxide) process.

The channel of the first switch 111 is coupled between a first node A and a second node B, and the first switch 111 is controlled by a first switch signal SW1 to turn on and off the channel.

The channel of the second switch 112 is coupled between a third node C and a fourth node D, and the conduction and disconnection of the channel of the second switch 112 are controlled by a second switch signal SW2.

The channel of the third switch 113 is coupled between a data voltage V _DATA and the third node C, and the conduction and disconnection of the channel of the third switch 113 are controlled by a third switch signal SW3.

The channel of the fourth switch 114 is coupled between the fourth node D and a common voltage V _COM , and the conduction and disconnection of the channel of the fourth switch 114 are controlled by the first switch signal SW1.

The channel of the fifth switch 115 is coupled between the fifth node E and a reference voltage V _REF , and the conduction and disconnection of the channel of the fifth switch 115 are controlled by the first switch signal SW1.

The PMOS transistor 120 has a source, a gate and a drain. The source is coupled to a DC supply voltage ELVDD, the gate is coupled to the first node A, and the drain is coupled to the second node B. The PMOS transistor 120 is used to output a driving current to the OLED element 140 via the drain.

The on-time modulation switch 121 is coupled between the second node B and the fifth node E, and the on-time modulation switch 121 controls its on-time according to a PWM signal EM.

The first capacitor 131 is coupled between the third node C and the first node A, and the second capacitor 132 is coupled between the fourth node D and a sixth node F. The first capacitor 131 and the second capacitor 132 are used to form a series circuit to store the data voltage V _DATA and sample the threshold voltage of the PMOS transistor 120 .

The OLED element 140 is coupled between the fifth node E and a negative DC voltage ELVSS, and generates corresponding brightness according to the driving current.

During operation, the AMOLED pixel compensation circuit 100 performs the following steps in sequence:

(I) First stage: Make (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, the on-time modulation switch 121) present (on, on, off, on, on, on) correspondingly, and refer to FIG. 2a for the situation, so that the voltage of the first node A is V _REF , the voltage of the second node B is V _REF , the voltage of the third node C is V _COM , the voltage of the fourth node D is V _COM , and the voltage of the fifth node E is V _REF , the voltage of the sixth node F is the logic 0 voltage of the first switch signal SW1, thereby initializing the gate voltage of the PMOS transistor 120 and the anode voltage of the OLED element 140 with a relatively stable voltage, so as to minimize the influence of the hysteresis voltage of the source-gate parasitic capacitance of the PMOS transistor 120 (that is, eliminate the residual value of the previous frame display voltage) and effectively reduce the short-term afterimage phenomenon of the display screen;

(ii) The second stage: make (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, the on-time modulation switch 121) present (on, on, off, on, on, off) correspondingly, and refer to FIG. 2b for the situation, so that the voltage of the first node A is (ELVDD+V _th ), the voltage of the second node B is (ELVDD+ V _th ), the voltage of the third node C is V _COM , the voltage of the fourth node D is V _COM , the voltage of the fifth node E is V _REF , and the voltage of the sixth node F is the logic 0 voltage of the first switch signal SW1, wherein V _th is the threshold voltage of the PMOS transistor 120;

(III) The third stage: make (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, the on-time modulation switch 121) present (off, on, off, off, off, off, off) correspondingly, and refer to FIG. 2c for the situation, so that the voltage of the first node A is (ELVDD+ _Vth +( _VH - _VL )*C2/(C1+C2)), the voltage of the third node C is ( _VCOM +( _VH - _VL )*C2/(C1+C2)), the voltage of the fourth node D is ( _VCOM +( _VH - _VL )*C2/(C1+C2)), and the voltage of the sixth node F is _VH , wherein V _H is the logic 1 voltage of the first switch signal SW1;

(iv) The fourth stage: make (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, the on-time modulation switch 121) present (off, off, on, off, off, off) correspondingly, and refer to FIG. 2d for the situation, so that the voltage of the first node A is (ELVDD+ _Vth + _VDATA - _VCOM ), the voltage of the third node C is _VDATA , the voltage of the fourth node D is ( _VCOM +( _VH - _VL )*C2/(C1+C2)), and the voltage of the sixth node F is _VH ; and

(V) Fifth stage: make (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, the on-time modulation switch 121) present (off, off, off, off, off, on) correspondingly, and refer to FIG. 2e for the situation, so that the voltage of the first node A is (ELVDD+ _Vth + _VDATA - _VCOM ), the voltage of the third node C is _VDATA , the voltage of the fourth node D is ( _VCOM +( _VH - _VL )*C2/(C1+C2)), and the voltage of the sixth node F is _VH , and the driving current can flow through the OLED element 140 to make the OLED element 140 emit light, and the driving current is independent of the threshold voltage of the PMOS transistor 120. The driving current can be expressed by the following formula:

, where I _OLED represents the driving current, W represents the channel width, and C _OX represents the oxide dielectric capacitance. represents the carrier mobility, and L represents the channel length. Thus, the driving current is independent of the threshold voltage _Vth and the DC supply voltage ELVDD, thereby providing a uniform brightness display effect.

Please refer to FIG. 2f, which shows a working timing diagram of the AMOLED pixel compensation circuit 100 of FIG. 1, wherein the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115 and the on-time modulation switch 121 are all PMOS transistors. As shown in FIG. 2f, T1 represents the first stage, T2 represents the second stage, T3 represents the third stage, T4 represents the fourth stage, and T5 represents the fifth stage.

In T1, EM is at a low potential (logic 0), SW1 is at a low potential (logic 0), SW2 is at a low potential (logic 0), and SW3 is at a high potential (logic 1), causing (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, and the on-time modulation switch 121) to correspondingly present (on, on, off, on, on, on).

In T2, EM is at a high potential, SW1 is at a low potential, SW2 is at a low potential, and SW3 is at a high potential, causing (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, and the on-time modulation switch 121) to correspondingly present (on, on, off, on, on, off).

In T3, EM is at a high level, SW1 is at a high level, SW2 is at a low level, and SW3 is at a high level, causing (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, and the on-time modulation switch 121) to correspondingly present (off, on, off, off, off, off, off).

In T4, EM is at a high level, SW1 is at a high level, SW2 is at a high level, and SW3 is at a low level, causing (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, and the on-time modulation switch 121) to correspondingly present (off, off, on, off, off, off, off).

In T5, EM is at a low potential, SW1 is at a high potential, SW2 is at a high potential, and SW3 is at a high potential, causing (the first switch 111, the second switch 112, the third switch 113, the fourth switch 114, the fifth switch 115, and the on-time modulation switch 121) to correspondingly present (off, off, off, off, off, off, on).

In addition, in order to extend the storage time of the gate voltage of the PMOS transistor 120, the first switch 111 can be implemented by an NMOS transistor.

Please refer to FIG. 2g, which shows a circuit diagram of another embodiment of the AMOLED pixel compensation circuit of the present invention. As shown in FIG. 2g, an AMOLED pixel compensation circuit 100a has an NMOS transistor 111a, a second switch 112a, a third switch 113a, a fourth switch 114a, a fifth switch 115a, a PMOS transistor 120a, a conduction time modulation switch 121a, a first capacitor 131a, a second capacitor 132a and an OLED element 140a, wherein the PMOS transistor 120a and the switches can be manufactured by a LTPO (low temperature polycrystalline oxide) process.

The channel of the NMOS transistor 111a is coupled between a first node A and a second node B, and the conduction and disconnection of the channel of the NMOS transistor 111a are controlled by a fourth switch signal SW4.

The channel of the second switch 112a is coupled between a third node C and a fourth node D, and the conduction and disconnection of the channel of the second switch 112a are controlled by a second switch signal SW2.

The channel of the third switch 113a is coupled between a data voltage V _DATA and the third node C, and the conduction and disconnection of the channel of the third switch 113a are controlled by a third switch signal SW3.

The channel of the fourth switch 114a is coupled between the fourth node D and a common voltage V _COM , and the on and off of the channel of the fourth switch 114a is controlled by the first switch signal SW1.

The channel of the fifth switch 115a is coupled between the fifth node E and a reference voltage V _REF , and the conduction and disconnection of the channel of the fifth switch 115a are controlled by the first switch signal SW1.

The PMOS transistor 120a has a source, a gate and a drain. The source is coupled to a DC supply voltage ELVDD, the gate is coupled to the first node A, and the drain is coupled to the second node B. The PMOS transistor 120a is used to output a driving current to the OLED element 140a via the drain.

The on-time modulation switch 121a is coupled between the second node B and the fifth node E, and the on-time modulation switch 121a controls its on-time according to a PWM signal EM.

The first capacitor 131a is coupled between the third node C and the first node A, and the second capacitor 132a is coupled between the fourth node D and a sixth node F. The first capacitor 131a and the second capacitor 132a are used to form a series circuit to store the data voltage V _DATA and sample the threshold voltage of the PMOS transistor 120a.

The OLED element 140a is coupled between the fifth node E and a negative DC voltage ELVSS, and generates corresponding brightness according to the driving current.

Please refer to FIG2h for the working timing of the AMOLED pixel compensation circuit 100a, wherein the second switch 112a, the third switch 113a, the fourth switch 114a, the fifth switch 115a and the on-time modulation switch 121a are all PMOS transistors. As shown in FIG2h, T1 represents the first stage, T2 represents the second stage, T3 represents the third stage, T4 represents the fourth stage, and T5 represents the fifth stage.

In T1, EM is at a low level (logic 0), SW1 is at a low level (logic 0), SW2 is at a low level (logic 0), SW3 is at a high level (logic 1), and SW4 is at a high level (logic 1), causing (NMOS transistor 111a, second switch 112a, third switch 113a, fourth switch 114a, fifth switch 115a, on-time modulation switch 121a) to correspondingly present (on, on, off, on, on, on).

In T2, EM is at a high level, SW1 is at a low level, SW2 is at a low level, SW3 is at a high level, and SW4 is at a high level, causing (NMOS transistor 111a, second switch 112a, third switch 113a, fourth switch 114a, fifth switch 115a, on-time modulation switch 121a) to correspondingly present (on, on, off, on, on, off).

In T3, EM is at a high level, SW1 is at a high level, SW2 is at a low level, SW3 is at a high level, and SW4 is at a low level, causing (NMOS transistor 111a, second switch 112a, third switch 113a, fourth switch 114a, fifth switch 115a, on-time modulation switch 121a) to correspondingly present (disconnect, on, disconnect, disconnect, disconnect, disconnect).

In T4, EM is at a high level, SW1 is at a high level, SW2 is at a high level, SW3 is at a low level, and SW4 is at a low level, causing (NMOS transistor 111a, second switch 112a, third switch 113a, fourth switch 114a, fifth switch 115a, on-time modulation switch 121a) to correspondingly present (off, off, on, off, off, off).

In T5, EM is at a low level, SW1 is at a high level, SW2 is at a high level, SW3 is at a high level, and SW4 is at a low level, causing (NMOS transistor 111a, second switch 112a, third switch 113a, fourth switch 114a, fifth switch 115a, on-time modulation switch 121a) to correspondingly present (off, off, off, off, off, on).

As can be seen from the above description, the present invention discloses an AMOLED pixel compensation circuit, which has a switch circuit, a PMOS transistor, a capacitor combination and an OLED element, the source of the PMOS transistor is coupled to a DC supply voltage, the cathode of the OLED element is coupled to a negative voltage, the switch circuit is used to execute a switch operation procedure to drive the PMOS transistor to generate a driving current so that the OLED element generates a brightness, and the switch operation procedure includes: the switch circuit forms a first configuration so that a reference voltage is coupled to the gate voltage of the PMOS transistor and the anode voltage of the OLED element; The switch circuit forms a second configuration so that the PMOS transistor and the capacitor combination are connected in series to form a circuit between a common voltage and the DC supply voltage to collect the threshold voltage of the PMOS transistor; the switch circuit forms a third configuration so that one end of the capacitor combination is coupled to a data voltage so that the components of the voltage presented at the other end include the threshold voltage and the data voltage; and the switch circuit forms a fourth configuration so that the PMOS transistor and the OLED element are connected in series to generate the driving current, wherein the driving current is determined by the difference between the DC supply voltage and the voltage at the other end of the capacitor circuit.

In a possible embodiment, the switch circuit and the PMOS transistor can be manufactured by a low temperature polycrystalline oxide process. In addition, any transistor in the switch circuit can be a PMOS transistor, an NMOS transistor or a CMOS transistor.

According to the above description, the present invention further proposes an OLED display device. Please refer to FIG. 3, which shows a block diagram of an embodiment of the OLED display device of the present invention. As shown in FIG. 3, an OLED display device 200 has a driving circuit 210 and an AMOLED panel 220, and the AMOLED panel 220 has a plurality of AMOLED pixel compensation circuits 221, wherein the AMOLED pixel compensation circuit 221 is implemented by the AMOLED pixel compensation circuit 100, and the driving circuit 210 is used to make each AMOLED pixel compensation circuit 221 light up the OLED element according to the aforementioned working sequence.

According to the above description, the present invention further proposes an information processing device. Please refer to FIG. 4, which shows a block diagram of an embodiment of the information processing device of the present invention. As shown in FIG. 4, an information processing device 300 has a central processing unit 310 and an OLED display device 320, wherein the central processing unit 310 is used to communicate with the OLED display device 320, and the OLED display device 320 is implemented by the OLED display device 200.

In addition, the information processing device 300 may be a portable computer, a smart phone, or a car computer.

Through the above disclosed design, the present invention has the following advantages:

1. The AMOLED pixel compensation circuit of the present invention can quickly equalize the source-gate voltage of the current source transistor of each OLED pixel in the process of displaying a frame, thereby minimizing the short-term afterimage caused by the hysteresis voltage of the source-gate parasitic capacitance of the current source transistor on the display image.

2. The AMOLED pixel compensation circuit of the present invention can compensate the threshold voltage of the current source transistor to minimize the display unevenness and Mura phenomenon caused by process deviation and voltage drop of the supply voltage.

3. The AMOLED pixel compensation circuit of the present invention can extend the holding time of the driving voltage to support low screen refresh rate.

4. The OLED display device of the present invention can minimize the short-term afterimage of the display screen by using the aforementioned AMOLED pixel compensation circuit.

5. The OLED display device of the present invention can minimize the display unevenness and Mura phenomenon caused by process deviation and voltage drop of the supply voltage through the aforementioned AMOLED pixel compensation circuit, and prolong the holding time of the driving voltage to support a low screen refresh rate.

6. The information processing device of the present invention can optimize the display effect and support low screen refresh rate through the aforementioned AMOLED pixel compensation circuit.

The present invention discloses only one of the preferred embodiments. Any partial changes or modifications that are derived from the technical concept of the present invention and are easily inferred by a person familiar with the art do not deviate from the scope of the patent right of the present invention.

In summary, this case shows that its purpose, means and effects are all different from the known technology, and it is the first invention that is practical and indeed meets the patent requirements for invention. We sincerely request the review committee to examine this carefully and grant a patent as soon as possible to benefit the society. This is our utmost prayer.

100:AMOLED pixel compensation circuit

111: First switch

112: Second switch

113: The third switch

114: The fourth switch

115: The fifth switch

120:PMOS transistor

121: On-time modulation switch

131: first capacitor

132: Second capacitor

140:OLED components

100a:AMOLED pixel compensation circuit

111a: NMOS transistor

112a: Second switch

113a: The third switch

114a: The fourth switch

115a: Fifth switch

120a: PMOS transistor

121a: On-time modulation switch

131a: first capacitor

132a: second capacitor

140a:OLED components

200:OLED display device

210:Drive circuit

220:AMOLED panel

221:AMOLED pixel compensation circuit

300: Information processing device

310: Central Processing Unit

320:OLED display device

FIG. 1 shows a circuit diagram of an embodiment of the AMOLED pixel compensation circuit of the present invention. FIG. 2a shows an equivalent circuit diagram of the AMOLED pixel compensation circuit of FIG. 1 operating in a first stage. FIG. 2b shows an equivalent circuit diagram of the AMOLED pixel compensation circuit of FIG. 1 operating in a second stage. FIG. 2c shows an equivalent circuit diagram of the AMOLED pixel compensation circuit of FIG. 1 operating in a third stage. FIG. 2d shows an equivalent circuit diagram of the AMOLED pixel compensation circuit of FIG. 1 operating in a fourth stage. FIG. 2e shows an equivalent circuit diagram of the AMOLED pixel compensation circuit of FIG. 1 operating in a fifth stage. FIG. 2f shows a working timing diagram of the AMOLED pixel compensation circuit of FIG. 1. FIG. 2g shows a circuit diagram of another embodiment of the AMOLED pixel compensation circuit of the present invention. FIG. 2h shows a working timing diagram of the AMOLED pixel compensation circuit of FIG. 2g. FIG. 3 shows a block diagram of an embodiment of the OLED display device of the present invention. FIG. 4 shows a block diagram of an embodiment of the information processing device of the present invention.

100:AMOLED pixel compensation circuit

111: First switch

112: Second switch

113: The third switch

114: The fourth switch

115: The fifth switch

120: PMOS transistor

121: On-time modulation switch

131: First capacitor

132: Second capacitor

140:OLED components

Claims (10)

An AMOLED pixel compensation circuit has a switch circuit, a PMOS transistor, a capacitor combination and an OLED element. The source of the PMOS transistor is coupled to a DC supply voltage, and the cathode of the OLED element is coupled to a negative DC voltage. The switch circuit is used to execute a switch operation procedure to drive the PMOS transistor to generate a driving current so that the OLED element generates a brightness, and the switch operation procedure includes: the switch circuit forms a first configuration so that a reference voltage is coupled to the gate voltage of the PMOS transistor and the anode voltage of the OLED element; the switch circuit The circuit forms a second configuration so that the PMOS transistor and the capacitor combination are connected in series between a common voltage and the DC supply voltage to collect the threshold voltage of the PMOS transistor; the switch circuit forms a third configuration so that one end of the capacitor combination is coupled to a data voltage so that the voltage presented at the other end includes the threshold voltage and the data voltage; and the switch circuit forms a fourth configuration so that the PMOS transistor and the OLED element are connected in series to generate the driving current, wherein the driving current is determined by the difference between the data voltage and the common voltage. The AMOLED pixel compensation circuit as described in claim 1, wherein the switch circuit and the PMOS transistor are manufactured by a low temperature polycrystalline oxide process. The AMOLED pixel compensation circuit as described in claim 2, wherein any transistor in the switch circuit is a transistor selected from a group consisting of PMOS transistors, NMOS transistors and CMOS transistors. An OLED display device has an AMOLED panel, the AMOLED panel has a plurality of AMOLED pixel compensation circuits, each of the AMOLED pixel compensation circuits has a switch circuit, a PMOS transistor, a capacitor combination and an OLED element, the source of the PMOS transistor is coupled to a DC supply voltage, the cathode of the OLED element is coupled to a negative DC voltage, the switch circuit is used to execute a switch operation procedure to drive the PMOS transistor to generate a driving current so that the OLED element generates a brightness, and the switch operation procedure includes: the switch circuit forms a first configuration to couple a reference voltage to the PMOS transistor; The gate voltage of the crystal and the anode voltage of the OLED element; the switch circuit forms a second configuration so that the PMOS transistor and the capacitor combination are connected in series between a common voltage and the DC supply voltage to collect the threshold voltage of the PMOS transistor; the switch circuit forms a third configuration so that one end of the capacitor combination is coupled to a data voltage so that the voltage presented at the other end includes the threshold voltage and the data voltage; and the switch circuit forms a fourth configuration so that the PMOS transistor and the OLED element are connected in series to generate the driving current, wherein the driving current is determined by the difference between the data voltage and the common voltage. An OLED display device as described in claim 4, wherein the switch circuit and the PMOS transistor are manufactured by a low temperature polycrystalline oxide process. An OLED display device as described in claim 5, wherein any transistor in the switch circuit is a transistor selected from a group consisting of PMOS transistors, NMOS transistors and CMOS transistors. An information processing device has a central processing unit and an OLED display device. The central processing unit is used to communicate with the OLED display device. The OLED display device has an AMOLED panel. The AMOLED panel has a plurality of AMOLED pixel compensation circuits. Each of the AMOLED pixel compensation circuits has a switch circuit, a PMOS transistor, a capacitor combination and an OLED element. The source of the PMOS transistor is coupled to a DC supply voltage, and the cathode of the OLED element is coupled to a negative DC voltage. The switch circuit is used to execute a switch operation procedure to drive the PMOS transistor to generate a driving current so that the OLED element generates a brightness, and the switch operation procedure includes: The switch circuit forms a first configuration so that a reference voltage is coupled to the gate voltage of the PMOS transistor and the anode voltage of the OLED element; the switch circuit forms a second configuration so that the PMOS transistor and the capacitor combination are connected in series between a common voltage and the DC supply voltage to collect the threshold voltage of the PMOS transistor; the switch circuit forms a third configuration so that the PMOS transistor and the capacitor combination are connected in series to form a circuit between a common voltage and the DC supply voltage to collect the threshold voltage of the PMOS transistor; The third configuration allows one end of the capacitor combination to couple a data voltage and the other end of the capacitor combination presents a voltage whose components include the threshold voltage and the data voltage; and the switch circuit forms a fourth configuration to connect the PMOS transistor and the OLED element into a series circuit to generate the driving current, wherein the driving current is determined by the difference between the data voltage and the common voltage. An information processing device as described in claim 7, wherein the switch circuit and the PMOS transistor are manufactured by a low temperature polycrystalline oxide process. An information processing device as described in claim 8, wherein any transistor in the switch circuit is a transistor selected from a group consisting of PMOS transistors, NMOS transistors and CMOS transistors. The information processing device as described in any one of claims 7 to 9 is a device selected from the group consisting of a portable computer, a smart phone and a car computer.

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