Method and apparatus for digitizing a voltage

US6949903B2 · kind B2 · utility

Assignee

• ebm-papst St. Georgen GmbH & Co. KG · DE

Inventors

• Hansjörg Berroth · Villingen-Schwenningen, DE
• Arnold Kuner · St. Georgen, DE
• Hans-Dieter Schondelmaier · St. Georgen, DE

Key dates

• Filing date: Nov 18, 2002
• Grant date: Sep 27, 2005
• Expiry date: Nov 18, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03M1/54
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

When digitizing a voltage, a capacitor is charged, through an impedance, to a voltage value (Um) dependent on the voltage to be digitized. The limits of that one of a plurality of voltage ranges in which said voltage value (Um) lies, are ascertained, and the two limits of that voltage range are defined as a first limit and second limit; the voltage at the capacitor is modified to the first limit by a charge modification circuit containing an impedance, and a first time interval needed therefor is identified; the voltage at the capacitor is modified to the second limit; the voltage at the capacitor is modified from the second to the first limit via the charge modification circuit. A seond time interval needed therefor is identified. Based on values of the first time interval and second time interval, a digital value is calculated, which serves as an indication of how much the voltage value (Um) at the capacitor differs from one of said two limits.