High-side current sense circuit with common-mode voltage reduction

US7633317B2 · kind B2 · utility

Assignee

• Analog Devices, Inc. · US

Inventors

• Evaldo M. Miranda · Saratoga, US
• Anthonius Bakker · Delft, NL

Key dates

• Filing date: May 17, 2007
• Grant date: Dec 15, 2009
• Expiry date: Jul 19, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G05F5/00
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A high-side current sense circuit comprises a sense resistance Rsense connected in series with a signal having an associated current to be measured I, which develops voltages V1 and V2 on either side of Rsense. A differential gain stage powered by supply voltages VCC and VEE produces an output voltage which varies with the difference between its input signals. To keep the common mode portion of the input signal between voltages VCC and VEE, a voltage modification circuit subtracts or adds a common mode voltage to or from V1 and V2 to produce modified voltages V1′ and V2′, which are coupled to the gain stage inputs. The voltage modification circuit is arranged to ensure that VEE≦V1′ and V2′≦VCC.