Removal of Hall Sensor Offset to Achieve Stable Spindle-Motor Loop in a CD System
Abstract
Brushless spindle motor is one of the most important key components used in a CD system. A stable spindle motor control loop is essential to assure reliable data integrity for a high-speed CD drive. However, DC offset is frequently observed on Hall sensors of the spindle motor used in a CD system. This spindle-motor Hall sensor offset also shows large range variation among batches from different motor suppliers. This undesired Hall sensor DC offset can induce unstable spindle-motor control loop and cause malfunction of a CD drive. Being a drive manufacturer to mass produce CD drives over one million unit per month, the problem of Hall sensor offset variation must be overcome to assure smooth operation of the mass production. As the demand on CD technology continues toward higher data transfer rate, the demand on spin rate stability of a spindle motor continues its advance. The increase of spin rate requires higher power consumption of a spindle motor and excessive heat is generated. This excessive heat aggravates the offset drifting in the Hall sensor and also induces amplitude shrinkage of Hall sensor signals. This undesired offset variation results in timing jitter of spindle-motor timing driving sequence to induce unstable spindle-motor loop in a CD system. In this paper, a practical solution is proposed to remove the offset completely, and thus, to achieve a very stable spindle loop.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2000
- Accession Number
- ADP011838
Entities
People
- Chi C. Lin
- Chin H. Lin
- Shum Y. Tung
- Wai W. Wang