Driving voltage sensing circuit and display device using the same

Patent metadata

Field	Value
Publication number	US-11087694-B2
Application number	US-201916673650-A
Country	US
Kind code	B2
Filing date	Nov 4, 2019
Priority date	Nov 7, 2018
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A driving voltage sensing circuit and a display device including the same. Deterioration of an organic light-emitting diode (OLED) disposed in each of subpixels is effectively compensated for by accurately sensing a change of charged capacitance depending on a current flowing through the organic light-emitting diode in a deterioration sensing period of the organic light-emitting diode. A driving voltage-for-sensing deterioration, applied to the display panel in the deterioration sensing period of the organic light-emitting diode, is maintained within a reference range. The deterioration of the organic light-emitting diode is accurately sensed by maintaining the driving voltage-for-sensing deterioration, applied in the deterioration sensing period, within the reference range.

First claim

The invention claimed is:

1. A display device, comprising:
a display panel including a plurality of gate lines, a plurality of data lines, and a plurality of subpixels formed adjacent to overlapping locations of the gate lines and the data lines;
a gate driver circuit driving the plurality of gate lines;
a data driver circuit driving the plurality of data lines;
a power management integrated circuit configured to supply a driving voltage-for-sensing deterioration to the display panel;
a driving voltage sensing circuit configured to:
sense whether or not the driving voltage-for-sensing deterioration supplied to the display panel is outside of a reference range; and
output a driving voltage sensing signal according to a result of the sensing; and

a timing controller controlling a supply of the driving voltage-for-sensing deterioration by the power management integrated circuit, in response to the driving voltage sensing signal transferred from the driving voltage sensing circuit,
wherein the driving voltage sensing circuit for sensing the driving voltage-for-sensing deterioration is supplied to the display panel in a deterioration sensing period in which deterioration of a plurality of organic light-emitting diodes of the display panel is sensed;
wherein the driving voltage sensing circuit includes:
a switch allowing the driving voltage-for-sensing deterioration to be supplied as an input signal in the deterioration sensing period;
a first comparator including an operational amplifier, wherein the driving voltage-for-sensing deterioration is supplied to an inverting input terminal of the first comparator through the switch, and the lowest value of the driving voltage-for-sensing deterioration is supplied to a non-inverting input terminal of the first comparator;
a second comparator including an operational amplifier, wherein the driving voltage-for-sensing deterioration is supplied to a non-inverting input terminal of the second comparator, and the highest value of the driving voltage-for-sensing deterioration is supplied to an inverting input terminal of the second comparator;
a first low-pass filter coupled to an output terminal of the first comparator to transfer a first driving voltage sensing signal from the first comparator to the timing controller; and
a second low-pass filter coupled to an output terminal of the second comparator to transfer a second driving voltage sensing signal from the second comparator to the timing controller.

2. The display device according to claim 1 , wherein each of the plurality of subpixels comprises:
an organic light-emitting diode;
a driving transistor driving the organic light-emitting diode, and having the driving voltage-for-sensing deterioration applied thereto, the driving transistor including a source node, a gate node, and a drain node;
a switching transistor electrically connected between the gate node of the driving transistor and a corresponding data line among the plurality of data lines; and
a sensing transistor electrically connected between either the source node or the drain node of the driving transistor and a reference voltage line.

3. The display device according to claim 1 , wherein the reference range corresponds to a range between a highest value of the driving voltage-for-sensing deterioration and a lowest value of the driving voltage-for-sensing deterioration, which are determined in consideration of accurately sensing the deterioration of the organic light-emitting diode within the display panel.

4. The display device according to claim 1 , further comprising:
a first register connected to the output terminal of the first low-pass filter; and
a second register connected to the output terminal of the second low-pass filter.

5. The display device according to claim 1 , wherein the timing controller is further configured to:
control the power management integrated circuit to increase the driving voltage-for-sensing deterioration if the first driving voltage sensing signal is in a logic high level; and
control the power management integrated circuit to decrease the driving voltage-for-sensing deterioration if the second driving voltage sensing signal is in a logic high level.

6. A driving voltage sensing circuit sensing a driving voltage supplied in a deterioration sensing period in which deterioration of a plurality of organic light-emitting diodes of a display panel is sensed, the driving voltage sensing circuit comprising:
a switch allowing the driving voltage to be supplied as an input signal in the deterioration sensing period;
a first comparator including an operational amplifier, wherein the driving voltage is supplied to an inverting input terminal of the operational amplifier through the switch, and a lowest value of the driving voltage is supplied to a non-inverting input terminal of the first comparator;
a second comparator including an operational amplifier, wherein the driving voltage is applied to a non-inverting input terminal of the second comparator, and a highest value of the driving voltage is supplied to an inverting input terminal of the second comparator;
a first low-pass filter coupled to an output terminal of the first comparator to transfer a first driving voltage sensing signal from the first comparator to the timing controller; and
a second low-pass filter coupled to an output terminal of the second comparator to transfer a second driving voltage sensing signal from the second comparator to the timing controller.

7. The driving voltage sensing circuit according to claim 6 , further comprising:
a first register connected to the output terminal of the first low-pass filter; and
a second register connected to the output terminal of the second low-pass filter.

8. A display device, comprising:
a power management integrated circuit configured to supply a driving voltage-for-sensing deterioration to a driving voltage sensing circuit;
the driving voltage sensing circuit configured to:
sense whether or not the driving voltage-for-sensing deterioration received is outside of a reference range; and
output a driving voltage sensing signal according to a result of the sensing; and

a timing controller electrically coupled to the driving voltage sensing circuit,
wherein the driving voltage sensing circuit includes:
a first comparator including a first operational amplifier having an output terminal, an inverting input terminal and a non-inverting input terminal;
a second comparator including a second operational amplifier having an output terminal, an inverting input terminal and a non-inverting input terminal;
a switch capable of selectively providing a sensing driving voltage, wherein one end of the switch is commonly connected to the inverting input terminal of the first comparator and the non-inverting input terminal of the second comparator, wherein the sensing driving voltage ranging between a lowest value and a highest value;
a first low-pass filter coupled to the output terminal of the first comparator; and
a second low-pass filter coupled to the output terminal of the second comparator,
wherein the lowest value of the sensing driving voltage is supplied to the non-inverting input terminal of the first comparator, and the highest value of the sensing driving voltage is supplied to the inverting input terminal of the second comparator.

9. The display device according to claim 8 , wherein the first comparator is configured to compare the lowest value of the sensing driving voltage and the sensing driving voltage, and the second comparator is configured to compare the highest value of the sensing driving voltage and the sensing driving voltage.

10. The display device according to claim 9

Assignees

• Lg Display Co Ltd

Inventors

• Park Kwangmo

Classifications

• G09G2320/045

  Compensation of drifts in the characteristics of light emitting or modulating elements · CPC title

• G09G2320/0295

  by monitoring each display pixel · CPC title

• G09G2330/028

  Generation of voltages supplied to electrode drivers in a matrix display other than LCD · CPC title

• G09G2310/0294

  Details of sampling or holding circuits arranged for use in a driver for data electrodes · CPC title

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title