Pulse Width Modulation (PWM) has been used extensively for motor control, DC-AC
converters, DC-DC converters and in audio applications. The conventional method of
generating a pulse width modulated signal involves generating an accurate sawtooth or triangle
wave using analog circuits. In CMOS, being analog circuit intensive puts extra constraints
on the fabrication process used for manufacture, thus requiring a higher cost than
digital CMOS. Delta-Sigma Modulation on the other hand is analog intensive, but requires
only quality capacitor matching, which can be obtained with current digital CMOS processes.
This thesis describes a method to generate a digital PWM with pulse dithering
using a Delta-Sigma modulator. The Delta-Sigma modulator provides accuracy and allows
the circuit to be implemented in a digital CMOS process, while the pulse dithering in the
PWM spreads out harmonic noise generated from the PWM fundamental frequency. / Graduation date: 1998
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33863 |
| Date | 14 July 1997 |
| Creators | Lewison, Richard S. |
| Contributors | Allstot, David J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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