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:
Feb. 22, 2005
Filed:
May. 06, 2003
Siegfried Tscheternigg, Vilgertshofen, DE;
Armin Wedel, Mering, DE;
Siegfried Tscheternigg, Vilgertshofen, DE;
Armin Wedel, Mering, DE;
Infineon Technologies AG, Munich, DE;
Abstract
A method for controlling the charging and discharging phases of a backup capacitor for a data storage medium has the step where the backup capacitor is first discharged to a defined voltage level before it is charged. The capacitor is discharged using a constant current. This ensures that the charging current for the backup capacitor cannot be used to identify what the charge-state of the capacitor was before discharging. Therefore, it is no longer possible to infer the currents that flowed during security-related arithmetic operations in a data processing unit. In one advantageous circuit configuration, a constant current source is formed by a current-mirror circuit, and a comparator is used to compare the voltage on the backup capacitor with a bandgap reference.