Method of increasing recording density of hard disc drive and controlling device thereof
View Patent ↗Provided is a method of increasing recording density and a control apparatus for increasing the recording density. The method includes applying a recording current corresponding to a recording signal to a magnetic head of a hard disc drive (HDD), and limiting a current value being applied to the magnetic head to a critical value when the recording current reaches the critical value. In the method, a rising time is reduced by using an overshoot recording current and the recording current is limited to a critical value when an actual recording current reaches the critical value. Thus, write track widths (WTWs) can be reduced at a low recording frequency, thereby increasing tracks per inch (TPI).
1. A method of increasing a recording density of a hard disc drive (HDD), the method comprising:
applying a recording current corresponding to a recording signal to a magnetic head of the HDD; and
limiting a value of a current being applied to the magnetic head to a critical value when the recording current reaches the critical value,
wherein the critical value corresponds to a maximum recording current that is actually applied to the magnetic head when recording information at a high frequency.
2. The method of claim 1 , wherein the limiting of the value of the current is performed by a clamping circuit disposed between the magnetic head and a preamplifier.
3. A method of increasing recording density of a hard disc drive (HDD), the method comprising:
applying a recording current corresponding to a recording signal to a magnetic head of the HDD;
determining a magnitude of a recording frequency;
setting a critical value by referring to a look-up table comprising critical values according to the recording frequencies; and
limiting a value of a current being applied to the magnetic head to the critical value when the recording current reaches the critical value.
4. The method of claim 3 , wherein the critical values in the look-up table are individually determined according to characteristics of the magnetic head and the recording medium of individual HDD.
5. The method of claim 3 , wherein a magnitude of the critical value increases according to an increase in the magnitude of the recording frequency.
6. The method of claim 5 , wherein the limiting of the value of the current is performed by a clamping circuit disposed between the magnetic head and a preamplifier.
7. The method of claim 3 , wherein the determining of the magnitude of the recording frequency comprises determining the number of consecutive data “0”.
8. The method of claim 3 , wherein, in the determining of the magnitude of the recording frequency, if the recording frequency is a high recording frequency, the setting of the critical value and the limiting of the value of the current are omitted.
9. A control apparatus of a hard disc drive (HDD) comprising:
a preamplifier that applies a recording current corresponding to a recording signal to a coil of a magnetic head of the HDD; and
a clamping circuit that limits the recording current to a critical value when the recording current reaches the critical value, wherein the critical value corresponds to a maximum recording current that is actually applied to the magnetic head when recording information at a high frequency.
10. The control apparatus of claim 9 , further comprising a multiplexer that outputs a first input signal inputted from the preamplifier and a second input signal inputted from the clamping circuit, selects the first input signal at a recording frequency higher than a critical frequency, selects the second input signal at other recording frequencies, and outputs the selected input signal to the magnetic head.
11. A preamplifier that applies a recording current to a coil of a magnetic head of a hard disc drive (HDD), the preamplifier comprising a clamping circuit that limits the recording current to a critical value when the recording current reaches the critical value, wherein the critical value corresponds to a maximum recording current that is actually applied to the magnetic head when recording information at a high frequency.