Voltage boost circuitry for hard drive write preamplifiers
AssigneesSony Corporation, Sony Electronics Inc.
InventorsMehrdad Nayebi, Murat Hayri Eskiyerli, Phil Shapiro
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Abstract
Higher write speeds in hard disk write preamplifiers require higher supply voltages. The voltage across an inductive write head, VL, is proportional to the value of inductance, L, and to the speed at which the write current is reversed, di/dt. Accordingly, the write current reversal time in inductive write-heads fundamentally depends on how large a voltage can be impressed across the write drive head. The proposed circuitry and method provides a voltage boost circuit for hard disk drive preamplifiers that satisfies the demand for improved rise-time while meeting the conflicting demand for maintaining a same supply voltage.
Claims4
A boost circuit, for a preamplifier having a mode of operation for providing a boost voltage to reverse the current in an inductive write head, the boost circuit comprising:
- a first switch having a first terminal and a second terminal, the second terminal coupled to ground;
- a first npn transistor having an emitter, a collector and a base;
- a capacitive element coupled between the emitter of said npn transistor and the first terminal of said first switch;
- and
- a second switch having a first terminal coupled to a supply voltage and a second terminal coupled to the first terminal of said first switch,
- wherein said first switch is an npn transistor, and
- further wherein said first switch is driven by an emitter-coupled pair of transistors.
In a data storage system having a plurality of magnetic transducers which read and write data to and from a magnetic medium, wherein the magnetic transducer write heads are inductive in operation, a write driver/preamplifier boost circuit comprising:
- a first switch having a first terminal and a second terminal, the second terminal coupled to ground;
- a first npn transistor having an emitter, a collector and a base;
- a capacitive element coupled between the emitter of said npn transistor and the first terminal of said first switch;
- and
- a second switch having a first terminal coupled to a supply voltage (Vcc) and a second terminal coupled to the first terminal of said first switch,
- wherein said first switch is an npn transistor, and
- further wherein said first switch is driven by an emitter-coupled pair of transistors.
Dependencies are inferred from the claim text.