Method and apparatus for servo data synchronization in a disc drive

• US 6,311,140 B1
• Filed: 11/27/2000
• Issued: 10/30/2001
• Est. Priority Date: 01/25/1999
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Morris, John C., Cvancara, Dustin M.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Raymond, Edward
• Application Number:
  US09/723,358
• Time in Patent Office: 337 Days
• Field of Search: 702/141, 702/142, 702/127, 702/1, 702/183, 702/145, 702/150, 702/189, 734/88, 734/91, 734/93, 734/94, 735/040.3, 735/040.2, 735/141.6, 324/160, 324/162, 318/649-651, 360/49, 360/130.32, 360/244.1, 360/245.8, 360/245.9, 369/33, 369/34, 708/854, 700/46, 700/94, 700/304
• US Class Current: 702/141
• CPC Class Codes: G11B 5/59611 Detection or processing of peak/envelop signals
• CPC Class Codes: G11B 5/5965 Embedded servo format G11B5/59655 takes precedence

Abstract

A sensor chip is provided that includes a sensing element and a sigma-delta circuit that cooperate to generate sensor samples at a sensor data rate and a buffer that stores sensor samples at the sensor data rate. Although the buffer stores the samples at the sensor data rate, it is capable of providing the samples to an external circuit at a higher data rate. In one embodiment, the sensor chip is able to provide the stored sensor samples to an off-chip component at a rate set by the off-chip component.

Claims

1. A sensor chip capable of being bonded to a surface to detect acceleration of the surface, the sensor chip comprising:

a sensing element, capable of affecting an electrical signal based on movement of the surface;

a sigma-delta circuit capable of interacting with the sensing element to generate sensor samples at a sensor data rate; and

a buffer, coupled to the sigma-delta circuit and capable of storing sensor samples from the sigma-delta circuit at the sensor data rate and capable of providing stored sensor samples at a rate that is higher than the sensor data rate.

2. The sensor chip of claim 1 further comprising an output terminal capable of carrying stored sensor samples read from the buffer.

3. The sensor chip of claim 2 further comprising a read-enable terminal capable of being connected to an external component such that the external component can enable a reading operation to read stored sensor samples from the buffer by applying a signal to the read-enable terminal.

4. The sensor chip of claim 3 further comprising a read clock terminal capable of being connected to an external component such that the external component can control the rate at which stored sensor samples are read from the buffer.

5. The sensor chip of claim 1 wherein the sensing element is a micro-electromechanical system.

6. A method for providing acceleration data corresponding to the acceleration of an object, the method comprising steps of:

(a) modifying an electrical signal within a sensor chip that is mounted to the object based on movement of the sensor chip;

(b) generating sensor samples within the chip at a sensor data rate by applying the electrical signal to a sigma-delta circuit within the chip;

(c) storing the sensor samples in a buffer on the chip at the sensor data rate; and

(d) providing the stored sensor samples to a circuit external to the chip at a rate that is higher than the sensor data rate.

7. The method of claim 6 wherein providing step (d) comprises receiving a read enable signal from a circuit external to the chip before providing the stored sensor samples.

8. The method of claim 6 wherein providing step (d) comprises receiving a read clock signal from a circuit external to the chip and providing the stored sensor samples at a rate set by the read clock signal.

9. A sensor chip for sensing the movement of an object to which the sensor chip is bonded, the sensor chip comprising:

a sensing element and sigma-delta circuit that together generate sensor samples indicative of movement of the object at a sensor data rate; and

buffer means located on the sensor chip for storing the sensor samples at the sensor data rate for later retrieval at some rate that is higher than the sensor data rate.