Fan system—rotation speed control circuit and method for rotation speed error auto-calibration thereof
US9490739B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 2013 |
| Grant date | Nov 8, 2016 |
| Priority date | — |
| Expiry date | Apr 12, 2035 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B30/70
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A rotation speed control circuit with function of auto-calibrating rotation speed error is disclosed. The rotation speed control circuit includes a first multiplexer, a second multiplexer, an error amplifier and a current compensation circuit. In calibration mode, the rotation speed control circuit selects a calibration clock signal and a calibration voltage through the first multiplexer and the second multiplexer correspondingly according to a mode switch signal, and adjusts current value of a first current accordingly. In other words, the rotation speed control circuit utilizes the first current to compensate error of the external capacitor through the calibration clock signal fixed and the calibration voltage fixed in the duration of calibration mode, so as to avoid that aging of the external capacitor leads to rotation speed error and then affects the whole operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.