- Document Number:
20060176597
- Appl. No:
11/052381
- Application Filed:
February 07, 2005
- نبذة مختصرة :
A write head drive circuit for a magnetic data storage device is configured to drive a write head with a write head degaussing current that is applied at the end of a write cycle. The write head degaussing current is an alternating current waveform with a programmable number of current pulses with decreasing amplitude and a frequency controlled by a CMOS ring oscillator. The CMOS ring oscillator includes switchable feedback paths to control its frequency. A programmable timer terminates the write head degaussing current after an interval of time dependent on signals that indicate the programmable number of current pulses and the frequency of the CMOS oscillator.
- Inventors:
Ngo, Tuan Van (Eden Prairle, MN, US); Brannon, Craig Matthew (Maplewood, MN, US); Price, John Joseph (Eagan, MN, US)
- Claim:
1. A write current circuit for a magnetic data storage device, comprising: a write head drive circuit adapted to selectively drive a write head with a write head degaussing current, wherein the write head degaussing current is an alternating current waveform with a programmable number of current pulses with decreasing amplitude and a frequency controlled by an oscillator; and a programmable timer, wherein the programmable timer is configured to terminate the write head degaussing current after an interval of time based on a signal indicating the programmable number of current pulses.
- Claim:
2. The write current circuit according to claim 1, wherein the write head is selectively driven with a current signal representing data to be stored in the magnetic data storage device.
- Claim:
3. The write current circuit according to claim 1, wherein the interval of time is dependent on the frequency of the oscillator.
- Claim:
4. The write current circuit according to claim 1, wherein the oscillator is a CMOS ring oscillator with at least one switchable feedback path that controls the oscillator frequency.
- Claim:
5. The write current circuit according to claim 1, wherein the amplitude of the write head degaussing current is controlled with a substantially exponentially decreasing current waveform.
- Claim:
6. The write current circuit according to claim 1, wherein the write head degaussing current is applied at the end of a write cycle.
- Claim:
7. The write current circuit according to claim 1, including means for applying the write head degaussing current at the end of a write cycle.
- Claim:
8. A method of configuring a write current circuit for a magnetic data storage device, comprising: selectively driving a write head with a write head degaussing current that is an alternating current waveform with a programmable number of current pulses with decreasing amplitude and frequency controlled by an oscillator; and terminating the write head degaussing current with a programmable timer that responds after an interval of time based on a signal indicating the programmable number of current pulses.
- Claim:
9. The method according to claim 8, including selectively driving the write head with a current signal representing data to be stored in the magnetic data storage device.
- Claim:
10. The method according to claim 8, including setting the interval of time dependent on the frequency of the oscillator.
- Claim:
11. The method according to claim 8, including using a CMOS ring oscillator for the oscillator, and using at least one switchable feedback path in the CMOS ring oscillator to control its frequency.
- Claim:
12. The method according to claim 8, including using a substantially exponentially decreasing current waveform to control the amplitude of the write head degaussing current.
- Claim:
13. The method according to claim 8, including applying the write head degaussing current at the end of a write cycle.
- Claim:
14. A write current circuit for a magnetic data storage device, comprising: means for selectively driving a write head with a write head degaussing current that is an alternating current waveform having a programmable number of current pulses with decreasing amplitude, the alternating current waveform having a frequency; and means for terminating the alternating current waveform after an interval of time dependent on the programmable number of current pulses.
- Claim:
15. The write current circuit according to claim 14, including means for selectively driving the write head with a current signal representing data to be stored in the magnetic data storage device.
- Claim:
16. The write current circuit according to claim 14, including means for setting the interval of time dependent on the frequency of the alternating current waveform.
- Claim:
17. The write current circuit according to claim 14, including means for controlling the frequency of the alternating current waveform.
- Claim:
18. The write current circuit according to claim 14, including means for controlling the amplitude of the alternating current waveform with a substantially exponentially decreasing waveform.
- Claim:
19. The write current circuit according to claim 14, including means for applying the write head degaussing current at the end of a write cycle.
- Current U.S. Class:
360046/000
- Current International Class:
11; 11
- الرقم المعرف:
edspap.20060176597
Processing Request
No Comments.