Storage device having write signal with multiple-slope data transition
View Patent ↗A hard disk drive or other disk-based storage device comprises a storage disk, a read/write head configured to read data from and write data to the disk, and control circuitry coupled to or otherwise associated with the read/write head. The control circuitry comprises a write driver configured to generate a write signal for data to be written to the storage disk, and a multiple-slope transition controller associated with the write driver and configured to control a data transition in the write signal such that the data transition comprises at least two different segments each having a different slope, with the transition controller comprising separate slope control mechanisms for each of the segments. By way of example, the data transition may comprise a dual-slope transition having first and second segments arranged sequentially between a start point and an end point of the data transition.
1. An apparatus comprising:
control circuitry adapted for association with a read/write head configured to read data from and write data to a storage disk, the control circuitry being configured to process data received from and supplied to the read/write head;
wherein the control circuitry comprises:
a write driver configured to generate a write signal for data to be written to the storage disk; and
a multiple-slope transition controller associated with the write driver and configured to control a data transition in said write signal such that said data transition comprises at least two different segments each having a different slope, said multiple-slope transition controller comprising separate slope control mechanisms for each of said segments.
2. The apparatus of claim 1 wherein the data transition comprises one of a rising transition and a falling transition.
3. The apparatus of claim 1 wherein the data transition comprises a dual-slope transition having first and second segments arranged sequentially between a start point and an end point of the data transition with the slope of the first segment being greater than the slope of the second segment.
4. The apparatus of claim 1 wherein the data transition comprises a dual-slope transition having first and second segments arranged sequentially between a start point and an end point of the data transition with the slope of the first segment being less than the slope of the second segment.
5. The apparatus of claim 1 wherein the data transition has at least one knee point located between a start point and an end point of the data transition, with a given knee point separating two sequentially-arranged segments of the data transition.
6. The apparatus of claim 5 wherein the data transition is a rising transition and the knee point is located in a rectangle defined by coordinates [T — 0, −Iw] and [T — 0+T_rise, Iw+OSA], where T — 0 denotes a start time of the data transition, T_rise denotes a rise time of the data transition, Iw denotes steady state current, OSA denotes overshoot amplitude, −Iw denotes a start current amplitude of the data transition, and Iw+OSA denotes an end current amplitude of the data transition.
7. The apparatus of claim 5 wherein the data transition is a falling transition and the knee point is located in a rectangle defined by coordinates [T — 0,Iw] and [T — 0+T_fall,−Iw-OSA], where T — 0 denotes a start time of the data transition, T_fall denotes a fall time of the data transition, Iw denotes steady state current, OSA denotes overshoot amplitude, Iw denotes a start current amplitude of the data transition, and −Iw-OSA denotes an end current amplitude of the data transition.
8. The apparatus of claim 1 wherein the multiple-slope transition controller is at least partially incorporated into the write driver.
9. The apparatus of claim 1 wherein the separate slope control mechanisms comprise:
a first controllable delay element arranged in a steady state path of the write driver for controlling a slope of a first one of the segments; and
a second controllable delay element arranged in an overshoot path of the write driver for controlling a slope of a second one of the segments.
10. The apparatus of claim 9 wherein the first and second controllable delay elements are independently controllable in a manner that allows different slopes to be established for steady state and overshoot segments of the data transition.
11. The apparatus of claim 9 wherein inputs of the respective first and second controllable delay elements are both adapted to receive the data to be written to the storage disk.
12. The apparatus of claim 9 wherein an output of the first controllable delay element is coupled to an input of a drive element of the steady state path, and an output of the second controllable delay element is coupled to an input of an overshoot generator of the overshoot path.
13. The apparatus of claim 1 wherein the control circuitry is fabricated in at least one integrated circuit.
14. A storage device comprising the apparatus of claim 1 .
15. A virtual storage system comprising the storage device of claim 14 .
16. The apparatus of claim 1 wherein the control circuitry further comprises:
at least one integrated circuit comprising a disk controller and read channel circuitry; and
a preamplifier coupled between said at least one integrated circuit and the read/write head;
wherein the write driver and its associated multiple-slope transition controller are implemented in the preamplifier.
17. The apparatus of claim 1 comprising a processor and a memory coupled to the processor, wherein at least a portion of the control circuitry is implemented by the processor executing software code stored in the memory.
18. The apparatus of claim 1 wherein the different slopes for each of said segments are controlled responsive to respective control signals applied to the multiple-slope transition controller.
19. The apparatus of claim 1 wherein a first slope for a first segment of said segments is controlled responsive to a first control signal applied to a first slope control mechanism, and a second slope for a second segment of said segments is controlled responsive to a second control signal applied to a second slope control mechanism.
20. A method comprising the steps of:
receiving data to be written to a storage disk of a storage device; and
generating a write signal for the data to be written to the storage disk, the write signal having a plurality of data transitions, with at least one of said data transitions comprising at least two different segments each having a different slope;
wherein the generating step comprises separately controlling each of said segments.
21. A non-transitory computer-readable storage medium having embodied therein executable code for performing the steps of the method of claim 20 .
22. A processing system comprising:
a processing device; and
a storage device coupled to the processing device and comprising at least one storage disk;
wherein the storage device further comprises:
a read/write head configured to read data from and write data to the storage disk; and
control circuitry configured to process data received from and supplied to the read/write head;
the control circuitry comprising:
a write driver configured to generate a write signal for data to be written to the storage disk; and
a multiple-slope transition controller associated with the write driver and configured to control a data transition in said write signal such that said data transition comprises at least two different segments each having a different slope, said multiple-slope transition controller comprising separate slope control mechanisms for each of said segments.