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. 11, 2018
Filed:
Feb. 17, 2017
Stmicroelectronics, Inc., Coppell, TX (US);
Ian Byers, Northville, MI (US);
STMicroelectronics, Inc., Coppell, TX (US);
Abstract
A first differential amplifier output drives a first winding of a stepper motor and a second differential amplifier output drives a second winding of the stepper motor. Inputs of the first and second differential amplifiers receive input drive signals generated by either a digital to analog converter or a pulse width modulator, where the input drive signals are phase offset sinusoids. Current flowing through a stepper motor winding is sensed to generate a current sense signal. A stall sensing circuit processes the current sense signal to determine whether the stepper motor has stalled by: taking a first derivative of the current sense signal to generate a first derivative signal; taking a second derivative of the current sense signal to generate a second derivative signal; and processing one or more of the current sense signal, the first derivative signal and the second derivative signal to detect a stepper motor stall condition.