Spindle motor back-EMF synchronous rectifier

• US 6,188,192 B1
• Filed: 07/30/1999
• Issued: 02/13/2001
• Est. Priority Date: 07/30/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Chen, Ching-Siang
• Primary Examiner(s): Ip, Paul
• Application Number:
  US09/364,518
• Time in Patent Office: 564 Days
• Field of Search: 318/560-696, 360/70-105, 361/23-32, 361/92, 361/91, 361/93
• US Class Current: 318/563
• CPC Class Codes: G11B 21/12 Raising and lowering; Back-spacing or forward-spacing along track; Returning to starting position otherwise than during transducing operation
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: H02P 25/034 Voice coil motors voice coil motors driven by DC power H02P7/025

Abstract

A disk drive system including a disk having a magnetic surface and suppported for rotation on a spindle, a magnetic head being movable relative to the magnetic surface, and a spindle motor for driving the spindle. The motor generates a back-EMF voltage during an emergency condition and switches said back-EMF voltage during said emergency condition. A comparator circuit compares different phases of back-EMF voltage, and a control circuit controls said plurality of switches to supply said back-EMF voltage to direct said head to a stored position.

Claims

1. A disk drive system, said system including a disk having a magnetic surface and supported for rotation on a spindle, a magnetic head being movable relative to said magnetic surface, and a spindle motor for driving said spindle, said system comprising:

said motor generating a back-EMF voltage during an emergency condition;

a plurality of switches for switching said back-EMF voltage during said emergency condition;

a comparator circuit for comparing different phases of back-EMF voltage; and

a control circuit to control said plurality of switches to supply said back-EMF voltage to direct said head to a stored position.

2. A disk drive system, as in claim 1, wherein said control circuit includes a truth table to generate control signals to control said plurality of switches.

3. A disk drive system, as in claim 1, wherein said plurality of switches includes an upper switch and a lower switch.

4. A disk drive system, as in claim 1, wherein said control circuit includes a latch circuit.

5. A method for operating a disk drive system, said system including a disk havig a magnetic surface and suppported for rotation on a spindle, a magnetic head being movable relative to said magnetic surface, and a spindle motor for driving said spindle, said method including the steps of:

generating a back-EMF voltage from said motor during an emergency condition;

switching said back-EMF voltage during said emergency condition;

comparing different phases of said back-EMF voltage; and

controlling said plurality of switches to supply said back-EMF voltage to direct said head to a stored position.

6. A method for operating a disk drive system, as in claim 5, wherein said control step includes accessing a truth table to generate control signals to control said plurality of switches.

7. A method for operating a disk drive system, as in claim 5, wherein said switching step includes switching an upper switch and a lower switch.

8. A method for operating a disk drive system, as in claim 5, wherein said control step includes latching a latch circuit.