Disk drive calibrating touchdown sensor
First Claim
1. A disk drive comprising:
- a disk;
a head actuated over the disk, the head comprising a touchdown sensor comprising a resistance; and
control circuitry operable to;
apply a bias signal at a first bias value to the touchdown sensor and measure a corresponding first resistance of the touchdown sensor;
apply the bias signal at a second bias value to the touchdown sensor and measure a corresponding second resistance of the touchdown sensor;
estimate a reference resistance of the touchdown sensor based on the first and second bias values and the first and second resistances; and
generate an operating bias value for the bias signal based on a predetermined operating temperature of the touchdown sensor, the reference resistance, and a thermal coefficient of resistance (TCR) of the touchdown sensor, wherein the TCR specifies a change in temperature of the touchdown sensor relative to a change in the resistance of the touchdown sensor,wherein the bias signal comprises a voltage and the control circuitry is operable to generate the operating bias value for the bias signal according to;
8 Assignments
0 Petitions
Accused Products
Abstract
A disk drive is disclosed comprising a head actuated over a disk, the head comprising a touchdown sensor. A bias signal is applied at a first bias value to the touchdown sensor and a corresponding first resistance of the touchdown sensor is measured. The bias signal is applied at a second bias value to the touchdown sensor and a corresponding second resistance of the touchdown sensor is measured. A reference resistance of the touchdown sensor is estimated based on the first and second bias values and the first and second resistances. An operating bias value is generated for the bias signal based on a predetermined operating temperature of the touchdown sensor, the reference resistance, and a thermal coefficient of resistance (TCR) of the touchdown sensor, wherein the TCR specifies a change in temperature of the touchdown sensor relative to a change in the resistance of the touchdown sensor.
-
Citations
23 Claims
-
1. A disk drive comprising:
-
a disk; a head actuated over the disk, the head comprising a touchdown sensor comprising a resistance; and control circuitry operable to; apply a bias signal at a first bias value to the touchdown sensor and measure a corresponding first resistance of the touchdown sensor; apply the bias signal at a second bias value to the touchdown sensor and measure a corresponding second resistance of the touchdown sensor; estimate a reference resistance of the touchdown sensor based on the first and second bias values and the first and second resistances; and generate an operating bias value for the bias signal based on a predetermined operating temperature of the touchdown sensor, the reference resistance, and a thermal coefficient of resistance (TCR) of the touchdown sensor, wherein the TCR specifies a change in temperature of the touchdown sensor relative to a change in the resistance of the touchdown sensor, wherein the bias signal comprises a voltage and the control circuitry is operable to generate the operating bias value for the bias signal according to; - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method of operating a disk drive comprising a head actuated over a disk, the head comprising a touchdown sensor comprising a resistance, the method comprising:
-
applying a bias signal at a first bias value to the touchdown sensor and measure a corresponding first resistance of the touchdown sensor; applying the bias signal at a second bias value to the touchdown sensor and measure a corresponding second resistance of the touchdown sensor; estimating a reference resistance of the touchdown sensor based on the first and second bias values and the first and second resistances; and generating an operating bias value for the bias signal based on a predetermined operating temperature of the touchdown sensor, the reference resistance, and a thermal coefficient of resistance (TCR) of the touchdown sensor, wherein the TCR specifies a change in temperature of the touchdown sensor relative to a change in the resistance of the touchdown sensor, wherein the bias signal comprises a voltage and the operating bias value for the bias signal is generated according to; - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
-
23. A disk drive comprising:
-
a disk; a head actuated over the disk, the head comprising a touchdown sensor comprising a resistance; and control circuitry operable to; apply a bias signal at a first bias value to the touchdown sensor and measure a corresponding first resistance of the touchdown sensor; apply the bias signal at a second bias value to the touchdown sensor and measure a corresponding second resistance of the touchdown sensor; estimate a reference resistance of the touchdown sensor based on the first and second bias values and the first and second resistances; generate an operating bias value for the bias signal based on a predetermined operating temperature of the touchdown sensor, the reference resistance, and a thermal coefficient of resistance (TCR) of the touchdown sensor, wherein the TCR specifies a change in temperature of the touchdown sensor relative to a change in the resistance of the touchdown sensor; apply the bias signal at the operating bias value to the touchdown sensor and measure a corresponding third resistance of the touchdown sensor; update the reference resistance of the touchdown sensor based on the first, second, and operating bias values and the first, second, and third resistances; and update the operating bias value for the bias signal based on the updated reference resistance.
-
Specification