A method and apparatus for maximising the sustainable flash of a handheld portable electronic device

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(11)

EP 2 053 459 A8

(12)	CORRECTED EUROPEAN PATENT APPLICATION
	Note: Bibliography reflects the latest situation

(15)	Correction information:
	Corrected version no 1 (W1 A1)

(48)	Corrigendum issued on:
	15.07.2009 Bulletin 2009/29

(43)	Date of publication:
	29.04.2009 Bulletin 2009/18

(21)	Application number: 08161786.2

(22)	Date of filing: 28.09.2007

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International Patent Classification (IPC):

G03B 15/05^(2006.01)

(84)	Designated Contracting States:
	AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR
	Designated Extension States:
	AL BA HR MK RS

(62)	Application number of the earlier application in accordance with Art. 76 EPC:
	07117584.8 / 2042919

(71)	Applicant: Research In Motion Limited
	Waterloo, Ontario N2L 3W8 (CA)

(72)	Inventors:
	Geris, Ryan Kitchener, Ontario, N2M 5G7 (CA) Winger, Lyall Waterloo, Ontario, N2T 1A6 (CA) Book, Christopher Waterloo, Ontario, N2T 2S7 (CA)

(74)	Representative: Fennell, Gareth Charles et al
	Kilburn & Strode LLP 20 Red Lion Street London WC1R 4PJ London WC1R 4PJ (GB)


	Remarks:
	This application was filed on 05-08-2008 as a divisional application to the application mentioned under INID code 62.

(54)	A method and apparatus for maximising the sustainable flash of a handheld portable electronic device

(57) A method and apparatus for maintaining a maximum sustained flash current over the whole length of a flash using a programmable current drive in a handheld portable device powered by a battery. The method involves measuring the battery voltage before and after a flash is initiated and circulating the equivalent series resistance (ESR) of the battery. The calculated ESR is then used to adjust the flash current. The process may be repeated to correct for errors in the flash current.