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:
Jul. 24, 2001
Filed:
Aug. 04, 2000
Erkki Miettinen, Helsinki, FI;
ABB Industries Oy, Helsinki, FI;
Abstract
A galvanic isolation coupling of a current loop comprising an operational amplifier (A,) as a part of the current loop and an optoisolator (,) comprising two receivers. The isolation coupling also comprises a resistance (R,) that is connected in series to be a part of the current loop together with the operational amplifier (A,) and a transmitting LED (LED,) of the optoisolator, whereby the current loop is closed via the cathode of the transmitting LED (LED,), the coupling further comprising a zener diode (Z) and a capacitor (C,) connected in parallel and arranged between the positive and the negative voltage feed points of the operational amplifier, a photodiode (LED,) whose anode is coupled to the operational amplifier output (A,out) and the cathode to the cathode of the transmitting LED (LED,), a resistance (R,) whose first pole is coupled to a first pole (,) of the resistance (R,) and a second pole is coupled to the negative input (Uin−) of the operational amplifier, whereby the cathode of a first receiving PIN diode (PIN,) of the optoisolator (,) is coupled to the negative input (Uin−) of the operational amplifier and the anode is coupled to the cathode of the transmitting LED (LED,), and a circuit (,) that is galvanically isolated from the current loop, the circuit comprising a second receiving PIN diode (PIN,) of the optoisolator (,).