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. 03, 1984
Filed:
Jun. 14, 1982
Carlo Fare, Limito, IT;
Honeywell Information Systems Italia, Caluso, IT;
Abstract
A stepping motor drive circuit having pairs of magnetically coupled phase windings (1, 3 and 2, 4), comprises current chopping control circuits (23, 24) for controlling the on/off switching of a plurality of driving transistors (5, 6, 7, 8) each coupled to a respective phase winding, and the circuits associated with each switching transistor for reducing their storage times and hence switching losses. More particularly, with reference to the switching transistor (5), the related circuit for storage time reduction comprises a series connected capacitor (25) and a diode (45). The circuit connects between one terminal of one winding (2) of the pair of phase windings which is magnetically coupled to the one winding (1) of the other pair connected to such switching transistor (5) and to the base of such transistor (5). As soon as the transistor (5) is caused to switch from ON to OFF, the circuit applies a reverse voltage pulse to the base of the transistor (5) causing a fast transition towards the cutoff region. Besides improving the stepping motor efficiency for a high chopping frequency, the arrangement makes it possible to use switching transistors that dissipate power and are less expensive.