Single wire digital width modulation for fan control with tachometer feedback
US6563284B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 2001 |
| Grant date | May 13, 2003 |
| Priority date | — |
| Expiry date | Dec 25, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/085
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a motor drive system which comprises a fan controller circuit operable to generate a PWM control signal for control of a motor speed. The fan controller circuit comprises a current detection circuit and a motor speed determination circuit. The system further comprises a fan driver circuit operable to drive a motor at a duty cycle based on the PWM control signal from the fan controller circuit. The fan driver circuit comprises a current sink circuit operable to draw current from the PWM control signal when the PWM control signal is high and when the motor reaches a predetermined position. In the addition, the current detection circuit is operable to detect the current draw on the PWM control signal and provide an indication signal to the fan speed determination circuit associated with such detection. Further, the motor speed determination circuit is operable to determine the speed of the motor based upon a timing associated with successive current draw detections. The present invention also relates to a method of determining a motor speed which comprises driving a motor at a duty cycle dictated by a PWM control signal and detecting a predetermined ro…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.