Title :
2.5 rad/sec/sup 2/ resolution digital output MEMS-based rotational accelerometer for HDD applications
Author :
Gola, A. ; Pasolini, F. ; Chiesa, E. ; Lasalandra, E. ; Tronconi, M. ; Ungretti, T. ; Baschirotto, A.
Author_Institution :
STMicroelectronics, Cornaredo, Italy
Abstract :
Mechanical vibration of a HDD can cause head mis-positioning. This effect can be compensated by using the device presented in the following. It is a capacitive rotational accelerometer sensor which uses MEMS. The vibrations of the disk drive cause tiny rotational displacements of the moving part of the MEMS structure, which are measured by sensing the small variations in capacitance that they cause. Capacitance changes as small as 0.05 fF can be measured by the device. The device operates as follows: the minute rotational vibrations are detected and measured in order to generate a feed-forward correction signal for the voice coil drive circuit to keep the head in the correct position. This allows the track spacing to be reduced significantly, increasing the storage density per unit area. The circuit has been realized in a 0.61 /spl mu/m BiCMOS technology with an area of 9.5 mm/sup 2/. The power consumption is 150 mW from a single 5V supply.
Keywords :
BiCMOS integrated circuits; acceleration measurement; angular velocity measurement; capacitive sensors; disc drives; feedforward; hard discs; integrated circuit design; integrated circuit measurement; microsensors; vibrations; 0.05 fF; 0.61 micron; 150 mW; 5 V; BiCMOS MEMS-based rotational accelerometers; MEMS structure moving part rotational displacements; capacitance change measurement; capacitive rotational accelerometer sensors; circuit power consumption; die area; high resolution digital output accelerometers; mechanical vibration HDD head mis-positioning; micro-electro-mechanical systems; mis-positioning compensation; power supply voltage; rotational vibration detection; storage density per unit area increase; track spacing reduction; voice coil drive circuit feed-forward correction signal; Accelerometers; Capacitance measurement; Capacitive sensors; Circuits; Disk drives; Displacement measurement; Mechanical sensors; Micromechanical devices; Rotation measurement; Vibration measurement;
Conference_Titel :
Magnetic Recording Conference, 2002. Digest of the Asia-Pacific
Conference_Location :
Singapore
Print_ISBN :
0-7803-7509-2
DOI :
10.1109/APMRC.2002.1037650
