US3748554A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stepping motor drive circuit providing collapsing field energy storage
Assignee: Cambridge Thermionic Corp
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Filing: 1971-05-03
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Granted: 1973-07-24
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Expires: 1991-05-03
Abstract
Abstract A drive circuit for supplying current to individual coils of a stepping motor for the duration of a signal pulse, the drive circuit being characterized by a high rate of current decrease in the coil at the end of the signal pulse and efficient use of power sources. The drive circuit has a bridge configuration with the stepping motor coil connected across one bridge diagonal. Connected across the other bridge diagonal is an energizing potential such as a DC power source. Two opposite sides of the bridge have diodes connected therein, the diodes being oriented so as to be back biased by the energizing potential. The remaining two opposite sides of the bridge contain switching transistors, oriented so as to be forward biased by the energizing potential. Switch control means, responsive to the signal pulses, are provided to turn on the switching transistors at the beginning of a signal pulse to energize the coil, and to turn off the transistors at the end of a signal pulse so that the coil will discharge through the diodes back into the energizing potential for storage of the energy of discharge from the coil.
Inventors
- 👤 Donald C Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:12
CPC Classifications
H; H02; H02P; H02P8/00; H02P8/14; H02P8/16; H02P8/165
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
166 words
A stepping motor drive circuit for supplying current to a coil for the duration of a signal pulse comprising, in bridge configuration: a source of energizing power connected as one bridge diagonal; the coil being connected as the other bridge diagonal; diode means connected in each of two opposite bridge sides and being back biased by said energizing power source; controllable switch means in each of the remaining two opposite bridge sides; and control means for said switch means, responsive to a signal pulse, for turning on said switch means simultaneously to provide a first current path through said switch means for energizing of the coil, for turning off one of said switch means after a preselected time interval, said coil remaining energized after said time interval, and for turning off the other of said switch means at the end of said signal pulse to provide a second current path through said diode means for discharge of stored coil energy back into the energizing power source.
Claim 2
Dependent Claim
166 words
A stepping motor drive circuit for supplying current to a coil for the duration of a signal pulse comprising, in bridge configuration: a source of energizing power connected as one bridge diagonal; the coil being connected as the other bridge diagonal; diode means connected in each of two opposite bridge sides and being back biased by said energizing power source; controllable switch means in each of the remaining two opposite bridge sides; and control means for said switch means, responsive to a signal pulse, for turning on said switch means simultaneously to provide a first current path through said switch means for energizing of the coil, for turning off one of said switch means after a preselected time interval, said coil remaining energized after said time interval, and for turning off the other of said switch means at the end of said signal pulse to provide a second current path through said diode means for discharge of stored coil energy back into the energizing power source.
Claim 3
Dependent Claim
36 words
A stepping motor drive circuit according to claim 1 wherein said switch means comprise transistors forward biased by said energizing power source; and said control means includes a monostable multivibrator operative for said preselected time interval.
Claim 4
Dependent Claim
34 words
A stepping motor drive circuit according to claim 1 wherein said energizing power source includes a capacitive storage element and wherein energy is transferred from said coil to said element through said diode means.
Claim 5
Dependent Claim
194 words
A stepping motor drive circuit for supplying current to a coil for the duration of a signal pulse, comprising: an energizing power source; first circuit means providing a first current path through said power source and coil thereby to cause current to flow in said coil; second circuit means providing a second current path through said coil after a preselected time interval such that current is maintained in said coil after said time interval; third circuit means providing a third current path through said power source and coil such that current induced in the coil through the first and second circuit paths is directed in the third path back into the energizing power source; and control means for connecting the energizing power source and coil through the first circuit path at the beginning of a signal pulse, thereby to energize the coil, for connecting the coil through the second circuit path after said preselected time interval, thereby to maintain the coil energized, and for connecting the energizing power source and coil through the third circuit path at the end of said signal pulse, thereby to discharge the coil energy back into the power souRce.
Claim 6
Dependent Claim
194 words
A stepping motor drive circuit for supplying current to a coil for the duration of a signal pulse, comprising: an energizing power source; first circuit means providing a first current path through said power source and coil thereby to cause current to flow in said coil; second circuit means providing a second current path through said coil after a preselected time interval such that current is maintained in said coil after said time interval; third circuit means providing a third current path through said power source and coil such that current induced in the coil through the first and second circuit paths is directed in the third path back into the energizing power source; and control means for connecting the energizing power source and coil through the first circuit path at the beginning of a signal pulse, thereby to energize the coil, for connecting the coil through the second circuit path after said preselected time interval, thereby to maintain the coil energized, and for connecting the energizing power source and coil through the third circuit path at the end of said signal pulse, thereby to discharge the coil energy back into the power souRce.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |