Magnetic head swing clamp and cross-talk eliminator for read/write preamplifier

Claim 2

A magnetic head swing clamped read/write preamplifier responsive to mode signals which drive the preamplifier between read mode operation and write mode operation the magnetic head swing clamped read/write preamplifier comprising: a read differential transistor pair connected to an inductive magnetic head, each of the collectors of the transistors in the read differential transistor pair are connected to one of first and second read output terminals for providing first and second read output signals thereto; a write circuit connected to the inductive magnetic head for providing a write current thereto; a reference voltage generator comprising a first reference voltage output terminal, the reference voltage generator generating a first reference voltage level at the first reference voltage output terminal; a relatively negative voltage supply rail; and a positive voltage clamp circuit electrically connected to the first reference voltage output terminal and between the relatively negative voltage supply rail and each of the first and second read output terminals for limiting positive going voltage swings in the first and second read output signals as a function of the first reference voltage level.

Claim 3

The magnetic head swing clamped read/write preamplifier of claim 1 wherein the reference voltage generator further comprises a mode input terminal suited to receive the mode signals for driving the generator between read mode operation and write mode operation as a function of the mode signals.

Claim 4

The magnetic head swing clamped read/write preamplifier of claim 2 wherein the reference voltage generator further comprises voltage biasing circuitry connected to the mode input terminal and to the first reference voltage output terminal for varying the first reference voltage level as a function of the mode signals.

Claim 5

The magnetic head swing clamped read/write preamplifier of claim 1 wherein the positive voltage clamp comprises: a first transistor including first and second terminals forming a primary current flow path connected in series between the first read output terminal and the relatively negative voltage supply rail, and including a control terminal connected to the first reference voltage output terminal; and a second transistor including first and second terminals forming a primary current flow path connected in series between the second read output terminal and the relatively negative voltage supply rail, and including a control terminal connected to the first reference voltage output terminal.

Claim 6

The magnetic head swing clamped read/write preamplifier of claim 1 wherein: the reference voltage generator further comprises a second reference voltage output terminal that provides a second reference voltage level; and the magnetic head swing clamped read/write preamplifier further comprises a negative voltage clamp electrically connected to the second reference voltage output terminal and to the first and second read output terminals for clamping negative voltage swings in the first and second read output signals as a function of the second reference voltage level.

Claim 7

The magnetic head swing clamped read/write preamplifier of claim 5 wherein the negative voltage clamp comprises: a relatively positive voltage supply rail; a first transistor including first and second terminals forming a primary current flow path connected in series between the first read output terminal and the relatively positive voltage supply rail, and including a control terminal connected to the second reference voltage output terminal; and a second transistor including first and second terminals forming a primary current flow path connected in series between the second read output terminal and the relatively positive voltage supply rail, and including a control terminal connected to the second reference voltage output terminal.

Claim 8

A magnetic head swing clamped read/write preamplifier system of the type responsive to mode signals which drive a read/write preamplifier between read mode operation and write mode operation, the magnetic head swing clamped read/write preamplifier system comprising: a plurality of read/write preamplifiers with each of the plurality having a write circuit connected to an inductive magnetic head for providing a write current thereto and a read circuit having a read differential transistor pair connected to the inductive magnetic head, the transistors in the plurality of read differential transistor pairs having collectors which are connected together in parallel thereby providing first and second read output signals at first and second read output terminals; a reference voltage generator comprising a first reference voltage output terminal, the reference voltage generator generating a first reference voltage level at the first reference voltage output terminal; and a negative voltage clamp circuit electrically connected to the first reference voltage output terminal and to each of the collectors of the read differential pair of the plurality for limiting negative going voltage swings in each of the first and second read output signals as a function of the first reference voltage level.

Claim 9

A magnetic head swing clamped read/write preamplifier system of the type responsive to mode signals which drive a read/write preamplifier between read mode operation and write mode operation, the magnetic head swing clamped read/write preamplifier system comprising: a plurality of read/write preamplifiers with each of the plurality having a write circuit connected to an inductive magnetic head for providing a write current thereto and a read circuit having a read differential transistor pair connected to the inductive magnetic head, the transistors in the plurality of read differential transistor pairs having collectors which are connected together in parallel thereby providing first and second read output signals at first and second read output terminals; a reference voltage generator comprising a first reference voltage output terminal, the reference voltage generator generating a first reference voltage level at the first reference voltage output terminal; and a negative voltage clamp circuit electrically connected to the first reference voltage output terminal and to each of the collectors of the read differential pair of the plurality for limiting negative going voltage swings in each of the first and second read output signals as a function of the first reference voltage level.

Claim 10

The magnetic head swing clamped read/write preamplifier system of claim 7 wherein the reference voltage generator further comprises a mode input terminal suited to receive the mode signals for driving the generator between read mode operation and write mode operation as a function of the mode signals.

Claim 11

The magnetic head swing clamped read/write preamplifier system of claim 8 wherein the reference voltage generator further comprises voltage biasing circuitry connected to the mode input terminal and to the first reference voltage output terminal for varying the first reference voltage level as a function of the mode signals.

Claim 12

The magnetic head swing clamped read/write preamplifier system of claim 7 wherein the negative voltage clamp comprises: a relatively positive voltage supply rail; a first transistor including first and second terminals forming a primary current flow path connected in series between the first read output terminal and the relatively positive voltage supply rail, and including a control terminal connected to the first reference voltage output terminal; and a second transistor including first and second terminals forming a primary current flow path connected in series between the second read output terminal and the relatively positive voltage supply rail, and including a control terminal connected to the first reference voltage output terminal.

Claim 13

The magnetic head swing clamped read/write preamplifier system of claim 7 wherein: the reference voltage generator further comprises a second reference voltage output terminal that provides a second reference voltage level at the second reference voltage output terminal; and the magnetic head swing clamped read/write preamplifier system further comprises a positive voltage clamp electrically connected to the second reference voltage output terminal and to the first and second read output terminals for clamping positive voltage swings in the first and second read output signals as a function of the second reference voltage level.

Claim 14

The magnetic head swing clamped read/write preamplifier system of claim 11 wherein the positive voltage clamp comprises: a relative negative voltage supply rail; a first transistor including first and second terminals forming a primary current flow path connected in series between the first read output terminal and the relatively negative voltage supply rail, and including a control terminal connected to the second reference voltage output terminal; and a second transistor including first and second terminals forming a primary current flow path connected in series between the second read output terminal and the relatively negative voltage supply rail, and including a control terminal connected to the second reference voltage output terminal.

Claim 15

A magnetic head swing clamped read/write preamplifier system responsive to mode signals which drive a read/write preamplifier between read mode operation and write mode operation and including a write current switching circuit and a read circuit connected to an inductive magnetic head, the magnetic head swing clamped read/write preamplifier system comprising: a plurality of read/write preamplifiers with each of the read circuits having a differential transistor pair connected to an inductive magnetic head, the collectors of the transistors in the read differential transistor pair providing first and second read output signals at first and second read output terminals connected in parallel with the other read differential transistor pairs for connection to a read amplifier; a reference voltage generator comprising first and second reference voltage output terminals, the reference voltage generator generating a first reference voltage level at the first reference voltage output terminal and a second reference voltage level at the second reference voltage output terminal; a positive voltage clamp circuit electrically connected between the first reference voltage output terminal and each of the first and second read output terminals for limiting positive going voltage swings in the first and second read output signals as a function of the first reference voltage level; and a negative voltage clamp circuit electrically connected between the second reference voltage output terminal and each of the first and second read output terminals for limiting negative going voltage swings in the first and second read output signals as a function of the second reference voltage level.

Claim 16

A magnetic head swing clamped read/write preamplifier system responsive to mode signals which drive a read/write preamplifier between read mode operation and write mode operation and including a write current switching circuit and a read circuit connected to an inductive magnetic head, the magnetic head swing clamped read/write preamplifier system comprising: a plurality of read/write preamplifiers with each of the read circuits having a differential transistor pair connected to an inductive magnetic head, the collectors of the transistors in the read differential transistor pair providing first and second read output signals at first and second read output terminals connected in parallel with the other read differential transistor pairs for connection to a read amplifier; a reference voltage generator comprising first and second reference voltage output terminals, the reference voltage generator generating a first reference voltage level at the first reference voltage output terminal and a second reference voltage level at the second reference voltage output terminal; a positive voltage clamp circuit electrically connected between the first reference voltage output terminal and each of the first and second read output terminals for limiting positive going voltage swings in the first and second read output signals as a function of the first reference voltage level; and a negative voltage clamp circuit electrically connected between the second reference voltage output terminal and each of the first and second read output terminals for limiting negative going voltage swings in the first and second read output signals as a function of the second reference voltage level.

Claim 17

The magnetic head swing clamped read/write preamplifier system of claim 13 wherein the reference voltage generator further comprises a mode input terminal suited to receive the mode signals for driving the generator between read mode operation and write mode operation as a function of the mode signals.

Claim 18

The magnetic head swing clamped read/write preamplifier system of claim 14 wherein the reference voltage generator further comprises voltage biasing circuitry connected to the mode input terminal and to the first and second reference voltage output terminals for varying the first and second reference voltage levels as functions of the mode signals.

Claim 19

The magnetic head swing clamped read/write preamplifier system of claim 13 wherein the positive voltage clamp comprises: a relatively negative voltage supply rail; a first transistor including first and second terminals forming a primary current flow path connected in series between the first read output terminal and the relatively negative voltage supply rail, and including a control terminal connected to the first reference voltage output terminal; and a second transistor including first and second terminals forming a primary current flow path connected in series between the second read output terminal and the relatively negative voltage supply rail, and including a control terminal connected to the first reference voltage output terminal.

Claim 20

The magnetic head swing clamped read/write preamplifier system of claim 13 wherein the negative voltage clamp comprises: a relatively positive voltage supply rail; a first transistor including first and second terminals forming a primary current flow path connected in series between the first read output terminal and the relatively positive voltage supply rail, and including a control terminal connected to the second reference voltage output terminal; and a second transistor including first and second terminals forming a primary current flow path connected in series between the second read output terminal and the relatively positive voltage supply rail, and including a control terminal connected to the second reference voltage output terminal.

Claim 21

A clamped read/write preamplifier system suited for use with a device providing a read mode select signal for reading information from a magnetic media and a write mode select signal for writing information to the magnetic media, the clamped read/write preamplifier system comprising: a plurality of inductive magnetic heads each of which having a pair of terminals electrically connected thereto; a plurality of write circuits each of which being electrically connected to each of the pair of terminals of one of the plurality of inductive magnetic heads for providing a write current thereto in response to the write mode select signal; a plurality of read preamplifier circuits each of which being electrically connected to each of the pair of terminals of one of the plurality of inductive magnetic heads and providing common read output signals for the plurality of the preamplifier circuits at a pair of read output terminals in response to the read mode select signal; a reference voltage generator for providing a reference voltage level at a reference voltage output terminal; a clamping circuit electrically connected to the reference voltage output terminal and between a voltage supply rail and at least one of the common read output terminals of the plurality of read preamplifier circuits for limiting voltage swings at the pair of read output terminals as a function of the reference voltage level; and coupling means for selectively coupling the clamping circuit to each of the pair of terminals of the plurality of inductive magnetic heads for clamping voltage swings as a function of the reference voltage level, with coupling of the clamping circuit being based on voltage swing magnitude at each of the pair of terminals for the plurality of inductive magnetic heads.

Claim 22

A clamped read/write preamplifier system suited for use with a device providing a read mode select signal for reading information from a magnetic media and a write mode select signal for writing information to the magnetic media, the clamped read/write preamplifier system comprising: a plurality of inductive magnetic heads each of which having a pair of terminals electrically connected thereto; a plurality of write circuits each of which being electrically connected to each of the pair of terminals of one of the plurality of inductive magnetic heads for providing a write current thereto in response to the write mode select signal; a plurality of read preamplifier circuits each of which being electrically connected to each of the pair of terminals of one of the plurality of inductive magnetic heads and providing common read output signals for the plurality of the preamplifier circuits at a pair of read output terminals in response to the read mode select signal; a reference voltage generator for providing a reference voltage level at a reference voltage output terminal; a clamping circuit electrically connected to the reference voltage output terminal and between a voltage supply rail and at least one of the common read output terminals of the plurality of read preamplifier circuits for limiting voltage swings at the pair of read output terminals as a function of the reference voltage level; and coupling means for selectively coupling the clamping circuit to each of the pair of terminals of the plurality of inductive magnetic heads for clamping voltage swings as a function of the reference voltage level, with coupling of the clamping circuit being based on voltage swing magnitude at each of the pair of terminals for the plurality of inductive magnetic heads.

Claim 23

A magnetic head swing clamped read preamplifier configured for connection to an inductive magnetic head, the read preamplifier comprising: a first transistor having a control terminal and a controlled terminal with the control terminal connected to the inductive magnetic head and with the controlled terminal providing a read output signal at a read output terminal; a reference voltage generator for providing a reference voltage level at a reference voltage output terminal; a voltage supply terminal; and a voltage clamp circuit connected to the reference voltage output terminal and between the controlled terminal and the voltage supply terminal for limiting voltage swings in the read output signal as a function of the reference voltage level.

Claim 24

A magnetic head swing clamped read preamplifier configured for connection to an inductive magnetic head, the read preamplifier comprising: a first transistor having a control terminal and a controlled terminal with the control terminal connected to the inductive magnetic head and with the controlled terminal providing a read output signal at a read output terminal; a reference voltage generator for providing a reference voltage level at a reference voltage output terminal; a voltage supply terminal; and a voltage clamp circuit connected to the reference voltage output terminal and between the controlled terminal and the voltage supply terminal for limiting voltage swings in the read output signal as a function of the reference voltage level.

Claim 25

The magnetic head swing clamped read amplifier of claim 19 wherein the voltage clamp circuit is a positive voltage clamp circuit for limiting positive going voltage swings in the read output signal.

Claim 26

The magnetic head swing clamped read amplifier of claim 19 wherein the voltage clamp circuit is a negative voltage clamp circuit for limiting negative going voltage swings in the read output signal.