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:
May. 31, 1988
Filed:
Feb. 12, 1987
Hans-Bodo Laue, Altenbeken, DE;
Nixdorf Computer AG, Paderborn, DE;
Abstract
A circuit arrangement for the control of the series switching element of a clocked power supply unit has a pulse signal (Vt) delivered by a pulse generator. The pulse-interval ratio of the pulse signal can be varied as a function of a regulating signal (Vc) derived from the output side of the power supply unit and delivered by way of an optoisolator (13). The portion of the circuit employed as pulse generator (1) includes an operational amplifier (10) with feedback at both inputs. One feedback branch of the amplifier (10) contains at the amplifier input a capacitance (15) and a variable resistance. The variable resistance is formed by the parallel connection of a phototransistor (132) of an optoisolator (13) and an ohmic resistor (12). Accordingly, it becomes possible to produce a variation of the pulse-interval ratio of the pulse signal (Vt) either solely by modification of the pulse length or solely by modification of the pulse intervals. One input of the operational amplifier (10) may be connected with a start-stop switching stage (3), which also uses an op-amp ( 20). The two operational amplifiers (10, 20), which both are employed as open collector voltage comparators, can also be made as part of an integrated unit.