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:
Dec. 21, 1993
Filed:
Sep. 12, 1991
Helmut L Schroder-Brumloop, Berlin, DE;
Sven-Oliver R Kersten, Berlin, DE;
Otis Elevator Company, Farmington, CT (US);
Abstract
Drivers for field-controlled switches are powered and switched on and off by the same combined command and power signal which consists of a command signal modulated by a clock signal forming a command envelope including a train of clock pulses. The invention prevents power from being lost by refreshing power during the PWM low state, such that the command high state pulses need not be used for restoring power. Power and a command to a field-controlled driver is provided by a combined command power signal consisting in the on-state of clock pulses, the groups being a function of switch signal pulse width, and in the off-state of absence of clock pulses. During the off-state of the driver, power is refreshed. In addition, by integration the clock pulses a dead time occurs within the driver circuit, while the driver is being switched on with different time constants.