The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 18, 2014
Filed:
Nov. 16, 2012
Fujitsu Semiconductor Limited, Yokohama, JP;
Hiroto Kodama, Yokohama, JP;
Akimitsu Tajima, Yokohama, JP;
Hideaki Kondo, Sagamihara, JP;
Osamu Moriwaki, Yokohama, JP;
Fujitsu Semiconductor Limited, Yokohama, JP;
Abstract
A power supply has first and second reference voltage sources; a step-down voltage generator, including a transistor supplied with a first voltage, a resistor string between the transistor and a second voltage, and an op-amp which controls the transistor, and outputting the voltage at a first node among nodes in the resistor string; switches, coupled to the nodes; a comparison circuit, which compares the voltage at a common node the switches coupling in common with the second reference voltage source; and a calibration control circuit, which selects any switch according to a comparison result to calibrate. During calibration, the calibration control circuit couples a second node among the nodes to a non-inverting terminal of the op-amp, and the first reference voltage source to an inverting terminal of the op-amp, and after calibration, couples the common node to the non-inverting terminal, and the second reference voltage source to the inverting terminal.