Use of motor winding as integrator to generate sawtooth for switch mode current regulator
US4420717A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 1980 |
| Grant date | Dec 13, 1983 |
| Priority date | — |
| Expiry date | Oct 6, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P8/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A stepper motor for use in peripheral devices such as electronic printing terminals has its coils selected for activation by selection circuitry, with its power provided by a switch mode current regulator. The switch mode regulator utilizes the selected motor winding as the storage element of the regulator and the voltage ramp derived from the current flow through the motor coil itself for comparison with a reference voltage. The output of the comparator circuit controls the state of a latch which has a fixed frequency clock input. The frequency of the latch output is fixed, but the on time and off time of the latch varies in accordance with the output of the comparator. A comparator and latch circuit therefore form a pulse width modulator which then regulates the on and off time of the switching regulator power transistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.