Integrated constant current source

US4651083A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Ulrich Lachmann · Munich, DE
• Erwin Krug · Munich, DE

Key dates

• Filing date: Jul 12, 1985
• Grant date: Mar 17, 1987
• Expiry date: Jul 12, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G05F1/561
• WIPO field: Control
• WIPO sector: Instruments

Abstract

An integrated constant-current source having an operational amplifier with an inverting input to which a reference voltage is feedable, and an output; a first stage to which the output is coupled and by which the output voltage of the operational amplifier is converted to a first current, the first stage being in a circuit wherein a reference resistor is connected from which, for coupling a voltage dropping across the reference resistor, the reference resistor is coupled to a non-inverting input of the operational amplifier; and a second stage coupled to the output of the operational amplifier for converting the output voltage of the operational amplifier to a second current, the second stage being in a circuit wherein a current reflector is connected for supplying an output current which is constant in a first approximation, the integrated constant current source includes a third stage coupled to the output of the operational amplifier and converting the output voltage thereof into another current, the third stage being in a circuit wherein another current reflector is connected, and another stage coupled to the reference resistor, the other current reflector conducting reflected …