Method and apparatus for providing current pulses to illumination source in imaging scanner
AssigneeSymbol Technologies, Inc.
InventorJames Giebel
Life of this patent
Estimating the term…
Abstract
A method and apparatus for providing current pulses to the illumination source in an imaging scanner. The method includes: (1) sensing a current supplied from a current port to obtain a current-monitoring signal; (2) controlling a charge current provided to a storage capacitor based on the current-monitoring signal; (3) measuring a parameter related to a voltage across the storage capacitor; and (4) generating a driving current for the illumination source by the illumination driver circuit, if the parameter is above a predetermined threshold value, to provide a driving current for a illumination source in an imaging scanner.
Claims15
An imager for imaging target objects comprising:
- an illumination source for providing illumination directed towards a target object;
- photosensitive elements located within the imager for capturing an image from the target object while the imager is activated during an exposure period;
- a current sensing circuit operative to provide a current-monitoring signal related to a current supplied from a current port;
- an illumination driver circuit operative to provide a driving current for the illumination source;
- a storage capacitor operative to supply a current to the illumination driver circuit to provide the driving current for the illumination source, wherein a total peak driving current for the illumination source exceeds a maximum current supplied from the current port;
- and
- a charger circuit operative to provide to the storage capacitor a charge current that depends upon the current-monitoring signal provided by the current sensing circuit.
An imager for imaging target objects comprising:
- an illumination source for providing illumination directed towards a target object;
- photosensitive elements located within said imager for capturing an image from the target object while the imager is activated during an exposure period;
- an illumination driver circuit operative to provide a driving current for the illumination source;
- a storage capacitor operative to supply a current to the illumination driver circuit to provide the driving current for the illumination source, wherein a total peak driving current for the illumination source exceeds a maximum current supplied from a current port;
- and
- a charger circuit operative to adjust a charge current provided to the storage capacitor for maintaining the current supplied from the current port substantially close to a predetermined value.
A method comprising:
- sensing a current supplied from a current port to obtain a current-monitoring signal;
- controlling a charge current provided to a storage capacitor based on the current-monitoring signal;
- measuring a parameter related to a voltage across the storage capacitor;
- and
- generating a driving current for the illumination source by the illumination driver circuit, if the parameter is above a predetermined threshold value, to provide a driving current for a illumination source in an imaging scanner having photosensitive elements located therein, wherein the illumination driver circuit is operatively coupled to the storage capacitor to receive a current therefrom, wherein a total peak driving current for the illumination source exceeds a maximum current supplied from the current port.
Dependencies are inferred from the claim text.