Head-medium contact detection using introduced heat oscillation

摘要

An apparatus includes a head transducer configured to interact with a magnetic recording medium and a heater configured to thermally actuate the head transducer. A thermal sensor at or near the head transducer is configured to produce a sensor signal. Circuitry is coupled to the heater and configured to cause an oscillation in heater power. The heater power oscillation causes an oscillation in the sensor signal. A detector is coupled to the thermal sensor and configured to detect head-medium contact using the oscillating sensor signal and heater power.

主权项

1. An apparatus, comprising:
a head transducer configured to interact with a magnetic recording medium; a heater configured to thermally actuate the head transducer; a thermal sensor situated at or near the head transducer and configured to produce a sensor signal; circuitry coupled to the heater and configured to generate a reference signal to cause an oscillation in power supplied to the heater, the heater power oscillation causing an oscillation in the sensor signal; and a detector coupled to the thermal sensor, the detector configured to:
detect a phase difference between the sensor and reference signals; ordetect an error between a curve fitted to the sensor signal and the reference signal; ordetect a difference in noise between the sensor and reference signals; andmeasure a rate of change in resistance, ΔR, of the thermal sensor;measure a rate of change in power, ΔP, supplied to the heater; anddetect head-medium contact based on ΔR and ΔP.