Capacitive Height Sensing with Variable Step Charge-to-Voltage Converter
AssigneeAvago Technologies International Sales Pte. Limited
InventorKin Wai Roy Chew
Life of this patent
Estimating the term…
Abstract
Solutions for capacitive height sensing (CHS) can include a multi-phase charge-to-voltage (C2V) converter. In some examples, a measurement cycle may begin with a coarse phase using a first voltage step and transition to a fine phase using a second, smaller voltage step. Control logic can be configured to manage the voltage steps and integrate charge from a variable capacitor associated with a head gimbal assembly (HGA). In some embodiments, an offset circuit may be used to increase measurement sensitivity. An output signal based on the integrated voltage may be indicative of the HGA's height.
Claims20
An apparatus, comprising:
- a charge-to-voltage converter configured to generate an integrated voltage based on charge from a variable capacitor formed by capacitance between a head gimbal assembly (HGA) and a media;
- a variable voltage source configured to provide a charging voltage to the variable capacitor;
- and
- logic configured to:
- control the variable voltage source to repeatedly charge the variable capacitor with a first voltage step during a first phase of a measurement cycle;
- control the variable voltage source to repeatedly charge the variable capacitor with a second voltage step during a second phase of the measurement cycle, wherein the second voltage step is smaller than the first voltage step;
- and
- generate an output signal indicative of a change in a height of the HGA relative to the media based on the integrated voltage generated by the charge-to-voltage converter.
A method, comprising:
- in a first phase of a measurement cycle:
- repeatedly charging a variable capacitor with a first voltage step, wherein the variable capacitor is formed by capacitance between a head gimbal assembly (HGA) and a media;
- and
- integrating charge from the variable capacitor to generate a first portion of an integrated voltage;
- in a second phase of the measurement cycle:
- repeatedly charging the variable capacitor with a second voltage step, wherein the second voltage step is smaller than the first voltage step;
- and
- integrating charge from the variable capacitor to generate a second portion of the integrated voltage;
- and
- generating, based on the integrated voltage, an output signal indicative of a change in a height of the HGA relative to the media.
A system, comprising:
- a head gimbal assembly (HGA) and a media, wherein a variable capacitor is formed by capacitance between the HGA and the media;
- and
- a circuit, comprising:
- a charge-to-voltage converter configured to generate an integrated voltage based on charge from the variable capacitor;
- a variable voltage source configured to provide a charging voltage to the variable capacitor;
- and
- logic configured to control the variable voltage source to:
- repeatedly charge the variable capacitor with a first voltage step during a first phase of a measurement cycle;
- repeatedly charge the variable capacitor with a second voltage step during a second phase of the measurement cycle, wherein the second voltage step is smaller than the first voltage step;
- and
- generate an output signal indicative of a change in a height of the HGA relative to the media.
Dependencies are inferred from the claim text.