Driving circuit for current programmed organic light-emitting diode displays

Patent metadata

Field	Value
Publication number	US-10078984-B2
Application number	US-35061006-A
Country	US
Kind code	B2
Filing date	Feb 9, 2006
Priority date	Feb 10, 2005
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

A load driving circuit for a load having a parasitic capacitance associated therewith is provided. The load being current programmed. The driving circuit has a data line having a voltage controlling the load, a feedback loop having a lowpass filter for monitoring the voltage of the data line; and a current source for providing a current to the data line; the current source being controlled by a signal line and an output from the lowpass filter.

First claim

What is claimed is:

1. A driving circuit for improving a settling time of current for a current programmed pixel, the current programmed pixel having a light emitting device, the light emitting device being current programmed, the driving circuit comprising:
a data line coupled to the current programmed pixel, for controlling the light emitting device;
a programmable current source for providing via the data line programming current to the current programmed pixel during a programming cycle; and
a positive feedback loop coupled to the data line including:
a first capacitor directly coupled to a node, the first capacitor acting as a low pass filter to mitigate high frequency noise, a node voltage of the node following a voltage of the data line;
a second capacitor directly coupled to the node, the second capacitor differentiating the node voltage generating a first current; and
a current mirror coupled to the node, the current mirror duplicating the first current and adding the duplicated first current to the programming current.

2. A driving circuit for improving a settling time of current for a current programmed pixel having a light emitting device, the light emitting device being current programmed, the driving circuit comprising:
a data line coupled to the current programmed pixel, for controlling the light emitting device;
a capacitor directly coupled to a node, a node voltage of the node following a voltage of the data line, the capacitor differentiating the node voltage generating a first current;
a programmable current source for providing via the data line programming current to the current programmed pixel during a programming cycle; and
a current mirror coupled to the node, the current mirror duplicating the first current and adding the duplicated first current to the programming current.

3. The driving circuit according to claim 2 wherein the light emitting device is an organic light emitting diode.

4. The driving circuit according to claim 2 , wherein an illumination of the light emitting device is responsive to the programming current provided by the data line.

5. The driving circuit according to claim 2 , wherein the light emitting device is controlled by a thin film transistor.

6. A display having an array of pixels each including an organic light emitting diode driven by the driving circuit according to claim 2 .

7. A method of improving a settling time of current for a current programmed pixel having a light emitting device in a display, the light emitting device being current programmed, the method comprising steps of:
providing, during a programming cycle from a programmable current source, programming current via a data line to a current-programmed pixel;
in a positive feedback loop, differentiating a node voltage of a node generating a first current, the node voltage following a voltage of the data line;
low pass filtering the node voltage; and
duplicating the first current and adding the duplicated first current to the programming current.

8. The method according to claim 7 , wherein the light emitting device is an organic light emitting diode.

Assignees

• Nathan Arokia
• Chaji Gholamreza
• Ignis Innovation Inc

Inventors

• Nathan Arokia
• Chaji Gholamreza

Classifications

• H05B33/08

  Electricity · mapped topic

• G09G2320/0295

  by monitoring each display pixel · CPC title

• G09G3/3283 Primary

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

• G09G3/3241

  the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror · CPC title

• G09G2320/0252

  Improving the response speed · CPC title