Patent Application
20210304675
The disclosure relates to a driver circuit, and particularly relates to a display driver and a display driving method.
In general, owing to the organic light emitting diode (OLED) display panel has a problem of the light brightness attenuation, the conventional display driver must be configured with additional current integrator circuits to sense the OLED display panel. Therefore, the conventional display driver of the OLED display panel has problems of high cost and high power consumption. Therefore, regarding how to reduce the cost of the display driver and achieve the effect of power saving, solutions of several embodiments are provided below.
The disclosure is directed to a display driver and a display driving method, and are capable of driving a display panel and sensing an electrical characteristic of the display panel.
The display driver of the disclosure is adapted for driving a display panel and sensing an electrical characteristic of the display panel. The display driver includes a first amplifier circuit. The first amplifier circuit is coupled to the display panel. The first amplifier circuit includes a first driving circuit, a first sensing circuit and a first operational amplifier. The first operational amplifier is coupled to the display panel through a first driving line and a first sensing line. The first driving circuit is coupled to the first operational amplifier. The first driving circuit is configured to provide a first driving signal to the display panel through the first operational amplifier and the first driving line during a driving period. The first sensing circuit is coupled to the first operational amplifier. The first sensing circuit is configured to receive a first sensing signal from the display panel through the first operational amplifier and the first sensing line during a first sensing period.
The display driving method of the disclosure is adapted to a display driver. The display driver includes a first amplifier circuit coupled to the display panel through a first driving line and a first sensing line. The first amplifier circuit includes a first driving circuit, a first sensing circuit and a first operational amplifier. The display driving method includes following steps. A first driving signal is provided by the first driving circuit to the display panel through the first operational amplifier and the first driving line during a driving period. A first sensing signal is received by the first sensing circuit from the display panel through the first operational amplifier and the first sensing line during a first sensing period.
Based on the above, according to the display driver and the display driving method of the disclosure, the display driver is capable of driving a display panel and sensing an electrical characteristic of the display panel by one operational amplifier to reduce the number of operational amplifiers in the display driver, and reduce the cost of the display driver.
To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the disclosure. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted,” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings.
In the embodiment of the disclosure, the display panel 200 includes a pixel array, the pixel array includes a plurality of pixels arranged in an array. The plurality of pixels may include at least one of a plurality red pixels, a plurality green pixels, a plurality blue pixels or a plurality white pixels. The display panel 200 may be an organic light emitting diode (OLED) display panel or a micro light emitting diode (LED) display panel, and the disclosure is not limited thereto. In the embodiment of the disclosure, the amplifier circuit 100 may be corresponded to one or more pixel of the display panel. In another embodiment of the disclosure, the amplifier circuit 100 may be coupled to one pixel through the driving line 101 for driving the one pixel, and coupled to another one pixel through the sensing line 102 for sensing the another one pixel, where the one pixel and the another one pixel may be same color pixels or different color pixels.
In the embodiment of the disclosure, the driving circuit 120 may include a receiver circuit (RX), a digital to analog converter (DAC) circuit, and so on. The driving circuit 120 is configured to provide the driving signal to one pixel of the display panel 200 during the driving period. In the embodiment of the disclosure, the sensing circuit 130 may include a transmitter circuit (TX), an analog to digital converter (ADC) circuit, and so on. The sensing circuit 130 is configured to obtain the sensing signal from the one pixel or another one pixel of the display panel 200 during the sensing period, and provide a processed signal to a post-stage processing circuit, so that the post-stage processing circuit may perform a determination of a light brightness attenuation degree of the display panel 200 to further perform a driving compensation on the display panel 200 accordingly.
In the embodiment of the disclosure, the switch 151 is coupled between the driving circuit 120 and the first input terminal of the operational amplifier 110. The switch 152 is coupled between the second input terminal and the output terminal of the operational amplifier 110. The switch 153 is coupled between the output terminal of the operational amplifier 110 and the driving line 101. The switch 154 is coupled between the sensing circuit 130 and the output terminal of the operational amplifier 110. The switch 155 is coupled between the second input terminal and the sensing line 102. The switch 156 is coupled between a reference voltage Vf1 and the sensing line 102. The switch 157 is coupled between a reference voltage Vf2 and the first input terminal of the operational amplifier 110. The switch 158 is coupled between a reference voltage Vf3 and the output terminal of the operational amplifier. In the embodiment of the disclosure, the first input terminal of the operational amplifier 110 may be a non-inverting input terminal, and the second input terminal of the operational amplifier 110 may be an inverting input terminal. It should be noted that, the amplifier circuit 100 may further include a control circuit, and the control circuit is configured to control the switches 151 to 158.
In the embodiment of the disclosure, the amplifier circuit 100 is a hybrid buffer structure, and the amplifier circuit 100 can be operated in a driving mode and a sensing mode in different periods. During the driving period, the amplifier circuit 100 is operated in a driving mode. More specifically, the switches 151, 152 and 153 are turned on, and the switches 154 and 155 are turned off, so that the operational amplifier 110 is operated as a voltage follower. Therefore, the driving circuit 120 may provide the driving signal to the display panel 200 through the operational amplifier 110 and the driving line 101 during the driving period. Therefore, the amplifier circuit 100 is capable of effectively providing the driving signal for driving the one pixel of display panel 200. In addition, during the driving period, the switch 156 may also be turned on, so as to provide the reference voltage Vf1 to the display panel 200 through the sensing line 102. In another embodiment of the disclosure, the amplifier circuit 100 may not include the switch 156.
In the embodiment of the disclosure, the first pixel 610 includes a photo diode 611, a storage capacitor 612 and transistor 613 to 615. A first terminal of the photo diode 611 is coupled to a reference voltage Vb. A first terminal of the storage capacitor 612 is coupled to a second terminal of the photo diode 611. A first terminal of the transistor 613 is coupled to a second terminal of the storage capacitor 612, and a second terminal of the transistor 613 is coupled to the first driving line 511 via the circuit node N11. A first terminal of the transistor 614 is coupled to a reference voltage Va, a second terminal of the transistor 614 is coupled to the second terminal of the photo diode 611, and a control terminal of the transistor 614 is coupled to the first terminal of the photo diode 611. A first terminal of the transistor 615 is coupled to the first sensing line 513 via the circuit node N12, and a second terminal of the transistor 615 is coupled to first terminal of the photo diode 611. In the embodiment of the disclosure, the second pixel 620 includes a photo diode 621, a storage capacitor 622 and transistor 623 to 625, and the third pixel 630 includes a photo diode 631, a storage capacitor 632 and transistor 633 to 635. The second pixel 620 and the third pixel 630 has same circuit architecture as the first pixel 610, and respectively coupled to the second amplifier circuit 520 and the third amplifier circuit 530 in the same coupling manner, therefore details circuit of the second pixel 620 and the third pixel 630 are not repeated. In the embodiment of the disclosure, the first sensing line 512, the second sensing line 522 and the third sensing line 532 are coupled together.
It should be noted that, the first amplifier circuit 510, the second amplifier circuit 520 and the third amplifier circuit 530 each include same circuit units as the amplifier circuit 100 of
Taking the second amplifier circuit 520 senses the first pixel 610 as an example, the first amplifier circuit 510 provides the first driving signal or other driving signal to the first pixel 610 through the first driving line 511 during a first sensing period, so that the transistor 614 is turned on by the transistor 613. Then, the second amplifier circuit 520 receives a sensing signal from the transistor 614 through the transistor 615, the circuit node N12 and the second sensing line 522 during the first sensing period. In the embodiment of the disclosure, the above sensing signal may be, for example, a source-to-drain current of the transistor 614. Thus, the operational amplifier (such as the operational amplifier 110 in
Further, owing to the second pixel 620 and the third pixel 630 are idle, therefore corresponding to the turn-on result of the switch 158 in
However, in another embodiment of the disclosure, the first pixel 610 may also be sensed by the third amplifier circuit 530. By that analogy, the second pixel 620 may be sensed by the first amplifier circuit 510 or the third amplifier circuit 530 during a second sensing period, and the third pixel 630 may be sensed by the first amplifier circuit 510 or the second amplifier circuit 520 during a third sensing period. In other words, each of pixels in the display panel 600 may be sensed by the amplifier circuit of the respective adjacent pixel without an additional amplifier circuit. Therefore, the display driver 500 of the disclosure can effectively reduce number of operational amplifiers, and reduce the cost of the display driver 500.
In summary, the display driver and the display driving method of the disclosure are capable of performing the driving operation and the sensing operation in different period through one operational amplifier by controlling the multiple switches, where the one operational amplifier is operated as a current integrator or a voltage follower in the different period. In other words, the display driver of the disclosure no need additional current integrator circuits to sense the display panel. Therefore, the display driver and the display driving method of the disclosure can effectively reduce the cost of the display driver and achieve the effect of power saving by a specific amplifier circuit design.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.
