Touch down detection with HDI sensor DC mode
US8976481B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Feb 18, 2014 |
| Grant date | Mar 10, 2015 |
| Priority date | — |
| Expiry date | Feb 18, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/6076
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Methods are provided for determining the heater power level of a dynamic flying height (DFH) type write head at which a touch down (TD) occurs. Each method makes use of the DC component of a head-disk interference (HDI) sensor and the determination of the TD heater energy is deduced from certain characteristics of the function relating heater power to HDI DC signal strength. Characteristics that provide reliable indication of a TD include points of minimum slope, structure of the slope's slope and the properties of a linear fit to the slope if the slope does not converge to a consistent value. It is found that the use of all methods in combination allow a reliable TD determination under virtually all conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.