Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2011-03-08
2011-03-08
Shalwala, Bipin (Department: 2629)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S086000, C345S207000
Reexamination Certificate
active
07903058
ABSTRACT:
A circuit and method for monitoring the forward voltage for a plurality of LEDs in a battery powered device so that the gain in the LED driver circuit can be switched at a point that optimizes the energy provided by the battery. The invention provides for sensing each LED's voltage, VLED, and determining the maximum forward voltage, VLEDmax, between the plurality of LEDs. The invention uses the knowledge of VLEDmaxin conjunction with VIN, converter output resistance and LED current, and current source/sink minimum headroom to switch from an initial gain to some higher gain just before the current sinks/sources would drop out, or from a higher gain to a lower gain in the event of the battery voltage going back to a voltage close to its initial value after being momentarily pulled down by a heavy load.
REFERENCES:
patent: 6897709 (2005-05-01), Henry
patent: 7489292 (2009-02-01), Kasai
patent: 2003/0169097 (2003-09-01), Henry
patent: 2004/0080361 (2004-04-01), Henry
patent: 2005/0017702 (2005-01-01), Kernahan et al.
patent: 2006/0033442 (2006-02-01), D'Angelo
patent: 2006/0109205 (2006-05-01), Deng
patent: 2006/0279562 (2006-12-01), Emek et al.
patent: 2007/0008255 (2007-01-01), Emek et al.
Maxim, “MAX1570 White LED Current Regulator with 1x/1.5x High-Efficiency Charge Pump,” Jul. 2000.
Semtech, “SC604 Low Noise, High Efficiency Regulated White LED Driver,” Revised Aug. 15, 2002.
Griesert Nathanael
Jacquet Florence
McIntyre William J.
Swank Damian
Chowdhury Afroza Y
National Semiconductor Corporation
Shalwala Bipin
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