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Negative Bias Resistor for Fast-Write Current Driver

IP.com Disclosure Number: IPCOM000100933D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Kurachi, K: AUTHOR [+3]

Abstract

Disclosed is a technique for designing a fast-write current driver which is used in digital magnetic recording. This technique allows higher recording frequency or more head coil turn (higher signal-to- noise ratio) by adding only two resistors in the conventional write driver circuit.

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Negative Bias Resistor for Fast-Write Current Driver

       Disclosed is a technique for designing a fast-write
current driver which is used in digital magnetic recording.  This
technique allows higher recording frequency or more head coil turn
(higher signal-to- noise ratio) by adding only two resistors in the
conventional write driver circuit.

      The figure shows an interface between a recording head and a
read/write electronic circuit.  Two resistors (designated RNBC) are
added for the following two purposes:

      One reason is to reduce the time constant in a transition of
write current by increasing head internal resistance equivalently.
To choose appropriate RNBC and damping resistor values allows
increasing transition speed while keeping the same overshoot in the
write current waveform.  Another reason is to prevent head amplitude
loss by increasing the input impedance of a read amplifier.

      This method requires additional power loss and voltage loss due
to the additional current (iNBC), but does not present problems
unless the RNBC is too great.