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EP0598446A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Motor drive circuit, as well as a data reading and/or recording apparatus comprising such a motor drive circuit

Assignee: Koninklijke Philips NV
•
Filing: 1993-11-11
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Granted: —
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Expires: 2013-11-11
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Abstract

Abstract A description is given of a motor drive circuit (9) for driving an electromotor (7) with a permanent magnet rotor and a stator comprising one or more stator windings (25, 26, 27). When the supply voltage of the motor drive circuit (9) fails, an emergency signal is generated by a signal generator (36). This emergency control signal activates an auxiliary power supply circuit for extracting electric energy from the motor and supplying the extracted energy to an auxiliary circuit (8). The auxiliary power supply circuit comprises a rectifier circuit formed by the fly back diodes (25c, 25d, 26c, 26d, 27c, 27d) bridging the switches (25a, 25b, 26a, 26b, 27a, 27b) of an electronic commutation circuit. The drive circuit comprises short-circuit switches (25e, 26e, 27e) bridging the stator windings (25, 26, 27). In response to the emergency control signal a short-circuit means (37) causes the stator windings (25, 26, 27) to be temporarily intermittently short-circuited. As a result, a capacitor (32) is charged. The energy stored in the capacitor (32) is used for temporarily feeding an auxiliary circuit (8) once the power supply to the drive circuit has failed. If the drive circuit is used in combination with a hard disc drive, the energy supplied by the auxiliary power supply circuit can be used for moving the magnetic head (3) to an idle position.

Inventors

  • 👤 Johannes P.M. C/O Int. Octrooibureau Bv Bahlmann
  • 👤 Henricus M. C/O Int. Octrooibureau Bv Van Hout

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-08 16:14
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/54; H; H02; H02P; H02P6/00; H02P6/34

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 151 words
Motor drive circuit for driving an electromotor with a permanent magnet rotor and a stator comprising one or more stator windings, the motor drive circuit comprising an excitation circuit for exciting the stator windings, a signal generation circuit for generating an emergency control signal which indicates a failure of the excitation of the stator windings, and an auxiliary power supply circuit for extracting electric energy from the motor in response to the emergency control signal and supplying the extracted energy to an auxiliary circuit, the auxiliary power supply circuit comprising a rectifier circuit inserted between at least one stator winding and the auxiliary circuit, characterized in that the drive circuit comprises a short-circuit means for short-circuiting the at least one stator winding coupled to the rectifier circuit, and a control means coupled to the short-circuit means for causing the stator winding(s) coupled to the rectifier circuit to be temporarily intermittently short-circuited.
Claim 2
Dependent Claim 45 words
Drive circuit as claimed in Claim 1, characterized in that the short-circuit means comprises control means for controlling the short-circuiting in response to the voltage level of the energy supplied to the auxiliary circuit in a manner in which said voltage level remains substantially constant.
Claim 3
Dependent Claim 30 words
Drive circuit as claimed in Claim 1 or 2, characterized in that the auxiliary power supply circuit is coupled to the short-circuiting means for supplying power to the short-circuiting means.
Claim 4
Dependent Claim 105 words
Data reading and/or recording apparatus comprising a motor for driving in a rotating fashion a disc having a recording layer, a read/write head arranged opposite the recording layer and movable in radial direction relative to the disc, an actuator for moving the head and a positioning control means for energizing the actuator, and a motor drive circuit as defined in the opening paragraph, the positioning control means for its energy supply being coupled to the auxiliary power supply circuit and the positioning control means being arranged for causing the magnetic head to be moved to an idle position in response to the emergency control signal.

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