Title:
METHOD AND APPARATUS FOR EFFICIENT MIXED SIGNAL PROCESSING IN A DIGITAL AMPLIFIER
Document Type and Number:
WIPO Patent Application WO2001003303
Kind Code:
A3
Abstract:
A system and method creating a highly efficient digital amplifier which can take either analog or digital inputs, and produce a high power accurate representation of the input to drive speakers or other low impedance load is described. The system employs a transition detector and delay unit which allows the comparator of the signal modulator to ignore its inputs for a pre-determined number of subsequent clock cycles once an output transition has been detected. Through the use of faster clocks and variable clock cycle skips upon the comparator's output transition, finer resolution of the feedback's clock period for noise-shaping purposes is achieved. Finer resolution of the clock period allows the present invention to employ a more aggressive noise-shaping than previously possible. In another aspect of the invention, additional delta-sigma modulator noise suppression is obtained by using the common bridge implementation of the power output stage with the improvement of configuring the bridge to create a 3-state condition instead of the conventional 2 states. By controlling the two halves of the bridge independently of one another, an output with 3 states makes for improved noise shaping performance.
Inventors:
OLSON ERLEND (US)
OPRIS ION (US)
OPRIS ION (US)
Application Number:
PCT/US2000/017596
Publication Date:
January 10, 2002
Filing Date:
June 27, 2000
Export Citation:
Assignee:
BROADCOM CORP (US)
OLSON ERLEND (US)
OPRIS ION (US)
OLSON ERLEND (US)
OPRIS ION (US)
International Classes:
H03F3/217; H03M3/02; H03M7/32; (IPC1-7): H03M7/00; H03M3/02; H03F3/217
Domestic Patent References:
| WO2000035082A1 | 2000-06-15 |
Foreign References:
| US5617058A | 1997-04-01 | |||
| US5508647A | 1996-04-16 |
Other References:
MAGRATH A J ET AL: "POWER DIGITAL-TO-ANALOGUE CONVERSION USING A SIGMA-DELTA MODULATOR WITH CONTROLLED LIMIT CYCLES", ELECTRONICS LETTERS,GB,IEE STEVENAGE, vol. 31, no. 4, 16 February 1995 (1995-02-16), pages 251 - 253, XP000513671, ISSN: 0013-5194
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