| US 7,515,188 B2 | ||
| Method and system for reducing mismatch between reference and intensity paths in analog to digital converters in CMOS active pixel sensors | ||
| R. Jacob Baker, Boise, Id. (US) | ||
| Assigned to Micron Technology, Inc., Boise, Id. (US) | ||
| Filed on Jul. 16, 2004, as Appl. No. 10/892,875. | ||
| Prior Publication US 2006/0012692 A1, Jan. 19, 2006 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. H04N 5/335 (2006.01); H04N 5/235 (2006.01) | ||
| U.S. Cl. 348—308 [348/221.1] | 14 Claims |
| 1. A circuit for coupling an intensity voltage and a reference voltage from an active pixel sensor to a processing circuit,
comprising:
a first pair of switches coupling an intensity input node to which the intensity voltage is applied to a first output node
and coupling a reference input node to which the reference voltage is applied to a second output node during a first operating
period;
a second pair of switches coupling the intensity input node to the second output node and coupling the reference input node
to the first output node during a second operating period; and
a polarity reversing circuit operative to couple the first and second output nodes to the processing circuit with one polarity
during the first operating period and in a reverse polarity during the second operating period.
|