CIRCUITRY FOR REVERSING A MAGNETIC FIELD

• Main Authors: BUECHLER, CHRISTIAN, ZUCKER, FRIEDHELM
• Format: Patent
• Language: English; Korean
• Published: 15.04.1999
• Edition: 6
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

An electromagnet is provided in magneto-optical recording and playback devices in order to be able to reverse the magnetisation of the magneto-optical layer of the magneto-optical disc as a function of the bits to be stored. To achieve a fast and reliable magnetisation reversal, a coil (S) is constructed from two series-connected windings (W1, W2) of opposite winding direction. The common junction point of the two windings (W1, W2) is connected via a series circuit of an inductance (L) and a current source (Q) to a supply voltage (U). The free terminal (B1) of one winding (W1) is connected to reference potential via a first diode (D1) and a parallel circuit of a capacitor (C) and a Zener diode (Z) connected in series thereto. The free terminal (B2) of the other winding (W2) is connected via a second diode (D2) to the common junction point of the first diode (D1) and the parallel circuit. The free terminal (B1) of one winding (W1) is connected to reference potential via a first controllable switch (S1) and the free terminal (B2) of the other winding (W2) is connected to reference potential via a second controllable switch (S2). For recording data, the controllable switches (S1, S2) are opened and closed in phase opposition by a drive circuit (AS) as a function of the bits to be stored. Magnetic and magneto-optical recording devices.