Pulse-width modulated (PWM) audio power amplifier having output signal magnitude controlled pulse voltage and switching frequency
US8093951B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 2009 |
| Grant date | Jan 10, 2012 |
| Priority date | — |
| Expiry date | Dec 18, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/351
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An audio switching power amplifier having an output pulse voltage selected in conformity with an indication of the output signal amplitude provides lower electromagnetic interference (EMI) in class-D amplifier implementations, in particular, in inductor-less designs. The output pulse voltage may be selected by providing multiple switching circuits, such as half or fully bridge switches, with each switching circuit connected to a different power supply. One of the switching circuits is activated by the switching controller, while the others are disabled, providing selection of the output pulse voltage. Selection of a lower pulse voltage, when the maximum voltage is not required, reduces the generated EMI. The switching frequency of the class-D amplifier may also be controlled in conformity with the output signal amplitude, so that at higher output levels a lower switching rate is selected, reducing the generated EMI.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.