The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Feb. 20, 2001

Filed:

May. 19, 1999
Applicant:
Inventors:

Osamu Katayama, Nagoya, JP;

Takahiro Iwamura, Kariya, JP;

Tetsuo Hirano, Anjo, JP;

Assignee:

Denso Corporation, Kariya, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02M 7/538 ; G05F 3/08 ;
U.S. Cl.
CPC ...
H02M 7/538 ; G05F 3/08 ;
Abstract

A device selectively supplying a high voltage and a ground level voltage to electrodes of an electroluminescent display panel. The voltage supply device includes a first and a second transistor connected in series, and outputs the high voltage upon turning on the first switching transistor and the ground level voltage upon turning on the second switching transistor. The device includes a circuit for selecting either an operation mode under which the device is normally operated with the high voltage or a test mode under which the device is tested under a low test voltage. The mode selection is performed by an external signal supplied to the device. Under the test mode, the switching transistors are turned on with a low gate voltage by operation of a circuit built in the device. Accordingly, the voltage supply device normally operated under the high voltage is easily tested under the low test voltage.


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