Microstepping bipolar stepping motor controller for document positioning
US5359271A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 25, 1993 |
| Grant date | Oct 25, 1994 |
| Priority date | — |
| Expiry date | Jan 25, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P8/22
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A controller for operating a stepping motor to a resolution defined by plural inter-pole motor positions includes a digital processor for communication with an external host system for controlling operation of the stepping motor, at least in a microstep mode. The processor selects Sine/Cosine driving current values for the motor windings from a table covering at least 90.degree., to define the inter-pole positions, stored in a RAMDAC or combination digital memory and digital to analog converter. The processor also controls scaling of the output of the digital to analog converter for different modes of operation, such as normal, hold and shutdown. The RAMDAC also can be loaded by the processor. Power stages are coupled to two analog outputs of the RAMDAC amplify the RAMDAC output signals, and provide a high power output to the windings using bridge drivers. The bridge drivers are enabled by analog comparators responsive to the analog input and to a current sense feedback, for enabling the bridge drivers until motor coil current reaches the value defined by the analog input, whereupon the driver is disabled and a one-shot is triggered to lock out the driver for preventing current ove…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.