Fly height control for hard disk drives

摘要

A fly height control circuit includes an input node to receive a digital control signal, an output node to output a control current to a resistive heater element to adjust a spacing between a read/write head and a surface of a storage medium, and control circuitry to process the digital control signal and generate the output control current based on the digital control signal. The control circuitry generates a first reference current based at least in part on the control current output from the output node. The control circuitry controls a slew rate of the first reference current to generate a slew rate controlled reference current. The control circuitry generates a second reference current based on a feedback voltage at the output node. The control circuitry compares the slew rate controlled reference current with the second reference current to adjust the control current output from the output node.

主权项

1. A fly height control circuit, comprising:
an input node to receive a digital control signal; an output node to output a control current to a resistive heater element to adjust a spacing between a read/write head and a surface of a storage medium; and control circuitry configured to process the digital control signal and generate the output control current based on the digital control signal, wherein the control circuitry generates a first reference current based on a proportional current that is proportional to the output control current, and an input control current that is generated based on the digital control signal, wherein the control circuitry controls a slew rate of the first reference current to generate a slew rate controlled reference current; wherein the control circuitry generates a second reference current based on a feedback voltage at the output node; and wherein the control circuitry compares the slew rate controlled reference current with the second reference current to adjust the output control current and thereby control a slew rate of an output voltage on the output node independent of a resistance value of the resistive heater element connected to the output node.