Voltage drop compensation system and method for power supply inside display panel

Patent metadata

Field	Value
Publication number	US-11183121-B2
Application number	US-202016984517-A
Country	US
Kind code	B2
Filing date	Aug 4, 2020
Priority date	Nov 29, 2018
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

A voltage drop compensation system and method for a power supply inside a display panel, to solve technical problems of poor uniformity of screen brightness and high power consumption of the whole screen due to voltage drop of the power supply inside the display panel. The voltage drop compensation system includes a voltage detection circuit and a voltage compensation circuit, where the voltage detection circuit is configured to detect an ELVDD voltage of pixel units in each row; and the voltage compensation circuit is configured to compensate a data voltage of pixel units in each row based on a detected ELVDD voltage.

First claim

What is claimed is:

1. A voltage drop compensation system for a power supply inside a display panel, comprising:
a voltage detection circuit electrically connected with pixel units in each row of the display panel through an ELVDD signal line and configured to detect an ELVDD voltage of the pixel units in each row; and
a voltage compensation circuit configured to compensate a data voltage of the pixel units in each row based on a detected ELVDD voltage, to obtain an equal absolute value of a voltage difference between the data voltage and the corresponding ELVDD voltage of the pixel units in each row;
wherein the ELVDD signal line is electrically connected with m rows of pixel units of the display panel respectively, the m rows of pixel units of the display panel are divided into n segmented areas along an extension direction of the ELVDD signal line, at least one of the n segmented areas is provided with a voltage detection point that is electrically connected with the voltage detection circuit, and m is a total number of the rows of pixel units of the display panel, wherein m≥1, and n≥1;
wherein the voltage detection circuit is configured to:
obtain a real-time voltage of pixel units in k-th row of the display panel, denoted as ELVDD(k), wherein

k
=

m
n

×
t

,

 1≤n≤m, 1≤t≤n, and t is a serial number of the voltage detection point; and
denote a detected real-time voltage of pixel units in 1-st row as ELVDD(1), and then calculate a real-time voltage of pixel units in any remaining row of the display panel by using a linear interpolation method, wherein the calculation equation is as follows:

ELVDD
⁡

(
i
)

=

ELVDD
⁡

(

m
n

×
t

)

-

ELVDD
⁡

(

m
n

×

(

t
-
1

)

)

m
n

×

(

1
-

m
×

(

t
-
1

)

n

)

+

ELVDD
⁡

(

m
n

×

(

t
-
1

)

)

wherein ELVDD(i) is a real-time voltage of pixel units in i-th row, i=2, 3, . . . , m.

2. The system according to claim 1 ,
wherein the voltage compensation circuit is configured to:
obtain a real-time voltage ELVDD(1) of pixel units in 1st row of the display panel; and
obtain an offset between the real-time voltage ELVDD(1) and a preset data voltage.

3. The system according to claim 2 , wherein the voltage compensation circuit is configured to
adjust a voltage offset of a Gamma power supply based on the offset, to remain a voltage difference between the real-time voltage ELVDD(1) and a peak voltage VGMP outputted from the Gamma power supply unchanged, and remain a voltage difference between the peak voltage VGMP and a valley voltage VGSP outputted from the Gamma power supply unchanged, wherein the Gamma power supply is configured to provide a compensation voltage for each pixel unit.

4. The system according to claim 1 , wherein the voltage compensation circuit is further configured to:
obtain an absolute value of a voltage difference between the real-time voltage of the pixel units in the i-th row and the detected real-time voltage of the pixel units in the 1st row of the display panel, denoted as |ELVDD(i)−ELVDD(1)|; and
based on the value of |ELVDD(i)−ELVDD(1)|, shift a data voltage Vdata(i) of the pixel units in the i-th row at an equal ratio to make |ELVDD(i)−Vdata(i)| be a same constant.

5. A voltage drop compensation method for a power supply inside a display panel, applied to a voltage drop compensation system for the power supply inside the display panel, with the system comprising a voltage detection circuit and a voltage compensation circuit, wherein the voltage detection circuit is electrically connected with pixel units in each row of the display panel through an ELVDD signal line, and the method comprises:
detecting an ELVDD voltage of the pixel units in each row by the voltage detection circuit; and
based on the ELVDD voltage, compensating a data voltage of the pixel units in each row by the voltage compensation circuit, to obtain an equal absolute value of a voltage difference between the data voltage and the corresponding ELVDD voltage of the pixel units in each row;
wherein the ELVDD signal line is electrically connected with m rows of pixel units of the display panel respectively, the m rows of pixel units of the display panel are divided into n segmented areas along an extension direction of the ELVDD signal line, at least one of the n segmented areas is provided with a voltage detection point that is electrically connected with the voltage detection circuit, and m is a total number of the rows of pixel units of the display panel, wherein m≤1, and n≤1;
wherein the detecting of the ELVDD voltage of the pixel units in each row comprises:
obtaining a real-time voltage of

Assignees

• Kunshan Govisionox Optoelectronics Co Ltd

Inventors

• Chen Xinquan
• Xu Chunsheng
• Zhang Xiaobao
• Wang Zheng

Classifications

• G09G3/3291 Primary

  in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements · CPC title

• G09G3/3233

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G2320/0233

  Improving the luminance or brightness uniformity across the screen · CPC title

• G09G2320/0673

  for control of gamma adjustment, e.g. selecting another gamma curve · CPC title

• G09G2330/021

  Power management, e.g. power saving · CPC title