Apparatus and method for current sensing for motor driver in pwm mode
US5689162A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Nov 18, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0009
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A motor drive control circuit for operation in the PWM mode includes a feedack circuit from a resistor for sensing motor coil current modified to switchably connect the resistor to the drive input in accordance with operation of a sample-hold switch. The sample-hold switch is controlled to sample a signal proportional to motor coil current only at the middle of the coil current rise during each PWM ON time, thus providing a reliable indication of average coil current. A signal storage capacitor connected in the feedback circuit receives the sampled signal and retains it for use in feedback control throughout PWM operation until the next sample.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.