US 7,554,383 B2
Chip for non-contact reader/writer having power-supply management function
Shigeru Arisawa, Tokyo (Japan); and Akihiko Yamagata, Kanagawa (Japan)
Assigned to Sony Corporation, (Japan)
Appl. No. 10/258,651
PCT Filed Mar. 04, 2002, PCT No. PCT/JP02/01945
§ 371(c)(1), (2), (4) Date Apr. 08, 2003,
PCT Pub. No. WO02/071325, PCT Pub. Date Sep. 12, 2002.
Claims priority of application No. 2001-59284 (JP), filed on Mar. 02, 2001.
Prior Publication US 2003/0141989 A1, Jul. 31, 2003
Int. Cl. G11C 5/14 (2006.01)
U.S. Cl. 327—530  [327/544; 327/407; 307/43; 307/80; 307/81] 6 Claims
OG exemplary drawing
 
1. A semiconductor integrated-circuit device comprising:
rectifying means for rectifying a received carrier wave;
generation means for generating a first power-supply voltage on the basis of an output by said rectifying means; and
selection means for selecting one of said first power-supply voltage generated by said generation means and a supplied second power-supply voltage as a power-supply voltage required for operation,
wherein said selection means selects said first power-supply voltage as the power-supply voltage required for operation when said second power-supply voltage is equal to or lower than a threshold value, and selects said second power-supply voltage as the power-supply voltage required for operation when said second power-supply voltage is equal to or higher than the threshold value and an instruction to operate in accordance with a predetermined function is given.