Motor speed control circuit with electronic clutch
US5410229A · kind A · utility
78Cited by
46References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1994 |
| Grant date | Apr 25, 1995 |
| Priority date | — |
| Expiry date | Feb 28, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/93
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The pulse width modulated DC motor speed control circuit indirectly senses motor current using sense MOSFETs and a peak detector circuit with storage capacitor for deriving an average motor current signal. The average motor current signal is used both in the feedback loop of the pulse width modulated speed control circuit and also in the motor shutoff or clutch circuit. The clutch circuit shuts off power to the motor when a user-settable torque is reached. The motor speed control circuit is therefore adapted for use in hand-held DC power tools such as screwdrivers and nutdrivers which stop rotation at a predefined torque.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.