Recording head with surface charge control
A data recording head may consist of at least a charge control circuit that has a substrate, ground, surface charge circuitry, and data reader circuitry. The substrate may be electrically isolated from the ground and electrically connected between the surface charge circuitry and a non-zero fixed voltage. The surface charge circuitry can be configured to apply a varying substrate charge to the substrate at a predetermined frequency to alter a head media spacing between the substrate and a data storage medium.
1. An apparatus comprising a charge control circuit resident in a preamplifier of a transducing head and comprising a substrate, ground, surface charge circuitry, and data reader circuitry, the substrate positioned proximal an air bearing surface (ABS), electrically isolated from the ground, and electrically connected between the surface charge circuitry and a non-zero fixed voltage, the surface charge circuitry configured to apply a varying substrate charge to the substrate at a predetermined frequency to alter a head media spacing between the substrate and a data storage medium.
2. The apparatus of claim 1 , wherein the predetermined frequency is dependent on a rotational speed of the data storage medium.
3. The apparatus of claim 1 , wherein the substrate comprises AlTiC.
4. The apparatus of claim 1 , wherein the surface control circuitry comprises first and second control lines extending from the substrate to respective first and second control modules.
5. The apparatus of claim 4 , wherein the first control line has a first resistor and the second control line has a second resistor, the first and second resistors connected in parallel to the substrate.
6. The apparatus of claim 4 , wherein the first and second resistors are different resistance values.
7. The apparatus of claim 4 , wherein the first and second resistors are each a common resistance value.
8. The apparatus of claim 4 , wherein a third resistor connects the first and second control lines, the third resistor being a different resistance value than the first and second resistors.
9. The apparatus of claim 1 , wherein the charge control circuit is positioned wholly on a single wafer.
10. An apparatus comprising a charge control circuit resident in a transducing head and comprising a substrate, ground, surface charge circuitry, and data reader circuitry, the data reader circuitry electrically connected to the ground, the substrate positioned proximal an air bearing surface (ABS), electrically isolated from the ground, and electrically connected between the first and second charge control modules of the surface charge circuitry, the first and second charge control modules each having a non-zero fixed voltage, the surface charge circuitry configured to apply a varying substrate charge to the substrate at a predetermined frequency to alter a head media spacing between the substrate and a data storage medium.
11. The apparatus of claim 10 , wherein the data storage medium has a surface charge, the surface charge attracted to the substrate charge.
12. The apparatus of claim 10 , wherein the substrate charge is supplied by a preamplifier via the surface charge circuitry.
13. The apparatus of claim 10 , wherein the predetermined frequency is static or oscillating.
14. The apparatus of claim 10 , wherein the non-zero fixed voltage is provided by the surface charge circuitry.
15. A method comprising:
positioning a charge control circuit on a wafer in a transducing head, the charge control circuit comprising a substrate, ground, surface charge circuitry, and data reader circuitry, the substrate positioned proximal an air bearing surface (ABS);
isolating the substrate electrically from the ground;
connecting the substrate electrically to first and second charge control modules of the surface charge circuitry the first and second charge control modules each having a non-zero fixed voltage; and
applying a varying substrate charge to the substrate with the surface charge circuitry, the varying substrate charge having a predetermined frequency to alter a head media spacing between the substrate and a data storage medium.
16. The method of claim 15 , wherein the substrate charge alters the head media spacing by being attracted to a surface charge of the data storage medium.
17. The method of claim 15 , wherein the substrate charge detects contact between the substrate and the data storage medium.
18. The method of claim 15 , wherein the substrate charge is altered from the first frequency to a second frequency to alter the head media spacing.
19. The method of claim 18 , wherein the first frequency is smaller than the second frequency.
20. The method of claim 15 , wherein a maximum voltage available from the surface charge circuitry is passed to the substrate without loss.