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:
Mar. 26, 2002
Filed:
Sep. 14, 2000
Andrea Merello, Arese, IT;
Gianluca Ventura, Cinisello Balsamo, IT;
Roberto Peritore, Trezzano Sul Naviglio, IT;
STMicroelectronics S.r.L., Agrate Brianza, IT;
Abstract
A method for controlling an electromagnetic actuator having an arm connected thereto uses a circuit that temporarily places in a high impedance state output nodes connected to a winding of the electromagnetic actuator. A detected BEMF is compared with a lower threshold and an upper threshold. Current in the electromagnetic actuator is monitored and controlled. A current pulse is provided to the electromagnetic actuator based upon the comparison of the detected BEMF with the lower and upper thresholds. The respective amplitudes of successively provided current pulses having a same polarity are progressively increased, and an amplitude of a provided current pulse having a polarity opposite a polarity of a preceding current pulse is decreased. The amplitude of the driving current pulses provided to the winding of the electromagnetic actuator advantageously adapts automatically to varying frictional conditions, or to any other cause of variation of the mechanical load of the actuator. These conditions occur when the arm moved by the electromagnetic actuator starts to slide up or flies off the parking ramp.