Driver circuit for a display device

• US 20020093992A1
• Filed: 01/08/2002
• Published: 07/18/2002
• Est. Priority Date: 01/09/2001
• Status: Active Grant

• Current Assignee: Callahan Cellular LLC (Intellectual Ventures LLC)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Plangger, Guido
• Granted Patent: US 6,972,755 B2
• Time in Patent Office: Days
• US Class Current: 370/535
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: Y10S 345/904 Display with fail/safe testing feature

Abstract

The invention relates to a device for driving display devices and to a display device that is provided with a driver circuit. The invention also relates to a method of testing driver circuits. Driver circuits of this kind have a decisive effect on the quality of the display devices. Therefore, in order to ensure a good quality, the driver circuit must be extensively tested, that is, with an as short as possible test time and using as few means as possible. In order to make such a test possible, a device for driving the display devices is provided with M leads that are coupled to A_N output stages that are provided with at least one multiplex device (4) and at least one amplifier unit (5), the M leads being coupled to a first switching device (2) that enables the interruption of a voltage supply to the M leads, and at least one second switching device (3) being provided in at least one output stage (A_N) in order to switch the output stage (A_N) to a selectable potential. This enables the use of a test that can be carried out digitally.

Claims

1. A device for driving a display device, which device is provided with M leads that are coupled to at least one multiplex device (4) and to a first switching device (2) that enables interruption of a voltage supply to the M leads, and also provided with at least one second switching device (3) that is coupled to the M leads and whereby at least one of the M leads can be switched to a selectable potential.

2. A device as claimed in claim 1, characterized in that the M leads are coupled to A_N output stages that are provided with at least one multiplex device (4) and at least one amplifier unit (5), and that at least one output stage (A_N) is provided with a second switching device (3) for switching the output stage (A_N) to a selectable potential.

3. A device as claimed in claim 1, characterized in that second switching devices (3) are provided in all output stages A_N.

4. A device as claimed in claim 1, characterized in that the multiplex device (4) that can be controlled by a digital signal is arranged to switch a voltage that is present on the M leads through to the output stage A_N.

5. A device as claimed in claim 1, characterized in that the second switching device (3) in the output stage (A_N) switches the lead M that is selected by the multiplex device (4) to a test reference potential.

6. A device as claimed in claim 1, characterized in that in a test mode the first switching device (2) connects the M leads to a common potential and separates them from this potential.

7. A device as claimed in claim 1, characterized in that a voltage generator generates at least one voltage for supply to the M leads.

8. A device as claimed in claim 1, characterized in that the switching devices (2, 3) can be controlled separately.

9. A display device that includes a driver circuit as claimed in the claims 1 to 8, in which the output stages A_N are connected to N terminals of a display device.

10. A method of testing a driver circuit, in which the driver circuit is supplied with at least one voltage on M leads, in which the M leads are coupled to a first switching device (2) and the voltage supply to the M leads is interrupted by means of the first switching device (2), in which one of the M leads is selected by means of at least one multiplex device that is coupled to the M leads, and in which the supplied voltage on the selected lead is switched to a test reference potential by means of a second switching device (3).