Delta-sigma modulator for a fan driver
US7863849B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 29, 2008 |
| Grant date | Jan 4, 2011 |
| Priority date | — |
| Expiry date | Jun 25, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P7/285
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fan driver circuit for powering a fan with a linear voltage may be designed using digital design techniques, resulting in a testable, accurate circuit on a smaller die size. The fan driver circuit may be configured to receive a digital control signal, which may be a sequence of numeric values, e.g. multiple-bit binary numbers, each indicative of a desired present rotational speed of the fan. The fan driver circuit may be implemented using a digital modulator, e.g. a delta-sigma modulator, with a simple low-pass filter, e.g. an RC-filter at the output, and may use oversampling based on a system clock, to shift in-band noise to out-of-band frequencies, and digital interpolation to filter out unwanted images from the upsampled digital control signal. The delta-sigma modulator may be constructed as a first-order delta-sigma modulator using an error-feedback structure to reduce die size.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.