Method of operating hard disk drives, corresponding hard disk drive and processing device
AssigneeSTMicroelectronics S.r.l.
InventorsMarco Ferrari, Davide Betta, Diego Tognoli, Roberto Trabattoni
Life of this patent
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Abstract
In accordance with an embodiment, a hard disk drive includes voice coil motors (VCMs) coupled to respective control units configured to drive retract an operation of the VCMs in the hard disk drive. The retract operation of the VCMs includes a sequence of retract steps. The control units are allotted respective time slots for communication over a communication line with the respective time slots synchronized via the common clock line, and are configured to drive sequences of retract steps of the VCMs in the hard disk drive in a timed relationship.
Claims20
A method, comprising:
- sensing, by a first voice coil motor (VCM) control circuit over a communication line configured to be coupled to a second VCM control circuit, signals indicative of a first sequence of retract steps being performed by a second VCM coupled to the second VCM control circuit;
- applying a clock signal on a common clock line, or receiving the clock signal on the common clock line, wherein the common clock line is different from the communication line;
- and
- driving, by the first VCM control circuit, a second sequence of retract steps, wherein the second sequence of retract steps is performed at a first VCM in a timed relationship to the first sequence of retract steps performed at the second VCM, and the timed relationship is synchronized with the clock signal.
A first voice coil motor (VCM) control circuit, comprising:
- a first finite state machine (FSM) configured to be coupled to a second VCM control circuit over a communication line, the first FSM configured to sense signals indicative of a first sequence of retract steps performed at a second VCM over the communication line;
- a second FSM coupled to the first FSM and having outputs configured to be coupled to the first VCM at a drive output, the second FSM configured to drive a second sequence of retract steps at the drive output, wherein the second sequence of retract steps is performed in a timed relationship to the first sequence of retract steps performed at the second VCM;
- and
- a clock interface circuit configured to be coupled to a clock line that is coupled to the second VCM control circuit.
A method of operating a hard drive system, the method comprising:
- controlling, by a master control circuit, a spindle motor of the hard drive system;
- generating, by the master control circuit, a back-electromotive force (BEMF) from the spindle motor;
- providing power generated from the BEMF to a slave control circuit coupled to the master control circuit, wherein the slave control circuit is coupled to a first VCM;
- applying, by the master control circuit, a clock signal on a common clock line coupled to the slave control circuit;
- and
- sensing, by the master control circuit over a communication line coupled to the slave control circuit, signals indicative of a first sequence of retract steps being performed by the first VCM, wherein the first sequence of retract steps is synchronized to the clock signal applied by the master control circuit.
Dependencies are inferred from the claim text.