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EP0048405A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Step motor driving circuit

Assignee: Bull HN Information Systems Italia SpA
•
Filing: 1981-09-10
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Granted: —
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Expires: 2001-09-10
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Abstract

Abstract A driving circuit for a four phases (1, 2, 3, 4) step motor, where each stable rotor position is reached by suitably energizing the series of two of the four phases, comprises a circuit (22) which controls the current in the energized phases by comparing a current related signal with a reference signal. Particularly, such circuit disconnects the series of two phases from the power supply and ground when the energization current reaches a predetermined upper threshold value and connect it again to the power supply and ground when the energization current, which is maintained in the phases through recycle diodes (9, 10, 11, 12), falls below a predetermined lower threshold value. In such way the energization current within the phases is kept nearly constant and this reduces to a minimum the winding copper losses, under the same mechanical performances. The cross configuration of the windings, with a current sensor (19) in the center of the cross, further enables to reduce to a minimum number the components of the control circuits.

Inventors

  • 👤 Roberto Cattoni

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-23 21:26
CPC Classifications
H; H02; H02P; H02P8/00; H02P8/12

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 183 words
Step motor driving circuit for a four-phases step motor where each stable rotor position is reached by suitable energization of the series of two of said four phases, characterized by that it compri ses: - four switching devices, each one coupled to one of said four pha ses, controlled through logical gates by first command pulses supplied by a control unit which controls with suitable sequence the contemporaneous closing of two of said switching devices; - an energization current sensor, always in series with any energi zed pair of said phases, providing at its output a signal propor tional to the energization current in said phase pairs; - a control circuit of said energization current which compares the output of said sensor with a reference signal and supplies with second command signals said switching devices through said logical gates, said control current together with said logical gates providing the opening of said switching devices when said energization current overcomes a predetermined upper threshold value and the further closing of said switching devices when said k current falls below a predetermined lower threshold value.
Claim 2
Dependent Claim 183 words
Step motor driving circuit for a four-phases step motor where each stable rotor position is reached by suitable energization of the series of two of said four phases, characterized by that it compri ses: - four switching devices, each one coupled to one of said four pha ses, controlled through logical gates by first command pulses supplied by a control unit which controls with suitable sequence the contemporaneous closing of two of said switching devices; - an energization current sensor, always in series with any energi zed pair of said phases, providing at its output a signal propor tional to the energization current in said phase pairs; - a control circuit of said energization current which compares the output of said sensor with a reference signal and supplies with second command signals said switching devices through said logical gates, said control current together with said logical gates providing the opening of said switching devices when said energization current overcomes a predetermined upper threshold value and the further closing of said switching devices when said k current falls below a predetermined lower threshold value.
Claim 3
Dependent Claim 50 words
Step motor driving circuit as claimed in claim 1 further characterized by that it comprises recycle diodes which enable to maintain said energization current within the winding pair selected by said control unit, during the time interval of said switching devices, said time interval being determined by said control circuit.
Claim 4
Dependent Claim 21 words
Step motor driving circuit as claimed in claim 1 where said current sensor consists in a resistor with low resistance value.

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