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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.

Patent No.:

US 8981653 B1

PDFFull Text
Date of Patent:
Mar. 17, 2015

Filed:

Mar. 15, 2013

Flash driver to limit a load current of a flash and method to limit a load current of a flash driver

Applicant:

Ams Ag, Unterpremstätten, AT;

Inventors:

Peter Trattler, Graz, AT;

Karl Georg Waser, Graz, AT;

Assignee:

ams AG, Unterpremstaetten, AT;

Attorney:

McDermott Will & Emery LLP

Primary Examiner:

Douglas W Owens

Assistant Examiner:

Christian L Garcia

Int. Cl.
CPC ...
H05B 41/00 (2006.01); H05B 41/30 (2006.01); H05B 41/16 (2006.01); H05B 41/36 (2006.01); G05F 1/00 (2006.01); G03B 7/26 (2006.01); G03B 15/05 (2006.01); H05B 33/08 (2006.01);
U.S. Cl.
CPC ...
G03B 15/05 (2013.01); H05B 33/0815 (2013.01); H05B 33/0824 (2013.01); Y02B 20/347 (2013.01);
Abstract

A flash driver to limit a load current for a flash comprises a dc/dc converter (DCDC) having a first input (IN) to receive an input voltage (Vin) and an output (OUT) to supply an output voltage (Vout). The dc/dc converter is designed to convert the input voltage (Vin) to the output voltage (Vout). Furthermore the flash driver has an adjustable current source (Iadj) connected between the output (OUT) and a load terminal (LT). A first control unit (CTRL) is connected to the first input (IN) and coupled to the adjustable current source (Iadj), and is designed to compare the input voltage (Vin) to a threshold (Vth) and, if the comparison indicates the input voltage (Vin) being smaller than the threshold value (Vth), adjust the adjustable current source (Iadj) such that the input voltage (Vin) is equal or greater than the threshold value (Vth). A second control unit (CTRL) is coupled to the adjustable current source (Iadj) and the dc/dc converter (DCDC) and is designed to detect a voltage drop over the adjustable current source (Iadj) and to set the dc/dc converter (DCDC) to control the conversion of input voltage (Vin) to the output voltage (Vout) depending on the detected voltage drop.

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