Patent ID: 6252440
Filing Date: 2001-06-26
Classification: G11B

Abstract:
A write driver circuit comprising: a reversal switching circuit having a pair of output terminals connected to both terminals of a magnetic head, for reversing the direction of a write current passing through the magnetic head in response to reversal of a write signal, and reversing means for reversing the write current by making a voltage difference between both terminals of the magnetic head in a period from reversal of the write signal to reversal of the write current to the magnetic head larger than a voltage difference between both terminals of the magnetic head, which occurs only in the reversal switching circuit, characterized in that the reversal switching circuit comprises: a first power source side transistor and a first ground side transistor which are connected in series in the forward direction between a power input terminal and a ground terminal; a second power source side transistor and a second ground side transistor which are connected in series in the forward direction between the power input terminal and the ground terminal; first switching means which is connected to the base of the first power source side transistor in response to a write signal; second switching means which is connected to the base of the second power source side transistor and controls the second power source side transistor in response to the write signal; third switching means which is connected to the base of the first ground side transistor and controls the first ground side transistor in response to the write signal; and fourth switching means which is connected to the base of the second ground side transistor and controls the second ground side transistor in response to the write signal, the magnetic head is connected between a connecting point of the first power source side transistor and the first ground side transistor and a connecting point of the second power source side transistor and the second ground side transistor, and the operation of a set of the first and fourth switching means and that of a set of the second and third switching means are reversed in response to reversal of the write signal to reverse the operation of a set of the first power source side transistor and the second ground side transistor and that of a set of the second power source side transistor and the first ground side transistor, thereby reversing the write current passing through the magnetic head.