Maximum duty cycle limiting of pulse width modulators
US5021937A · kind A · utility
18Cited by
4References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 18, 1989 |
| Grant date | Jun 4, 1991 |
| Priority date | — |
| Expiry date | Oct 18, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/33507
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus is disclosed for maintaining accurate control of the maximum duty cycle generated by pulse width modulators. The output signal of a pulse width modulation comparator is averaged and compared to a reference value. This reference value is proportional to the peak value of the comparator's output voltage. A closed loop circuit continually adjusts the duty cycle so the difference between the reference value and the average comparator output is nulled thereby providing an accurate maximum duty cycle output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.