Power down brake latch circuit for a brushless DC motor
US6005359A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1997 |
| Grant date | Dec 21, 1999 |
| Priority date | — |
| Expiry date | Jun 13, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/22
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A power down brake latch circuit for dynamically braking a spindle motor in a disk drive system is disclosed. The power down brake latch circuit includes a reservoir capacitor, a smoothing capacitor, a timing circuit, and a logic circuit. The timing circuit includes a voltage divider and a bandgap comparator. The smoothing capacitor absorbs a BEMF voltage from the spindle motor as it rotates after losing power. The timing circuit generates a first signal when a voltage on the smoothing capacitor falls below a threshold. The logic circuit brakes the spindle motor in response to the loss of power and the generation of the first signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.