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Multi-level Class-D amplifier by means of 2 physical layers

  • US 6,842,070 B2
  • Filed: 06/30/2003
  • Issued: 01/11/2005
  • Est. Priority Date: 04/17/2003
  • Status: Active Grant
First Claim
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1. A circuit to generate virtual multi-level output pulses for a Class-D Amplifier with only 2 physical levels, where the resulting time-voltage-area corresponds to a multiple of digital levels, comprising:

  • means to convert the input signal into a PDM (Pulse Density Modulated) signal;

    means to generate the output of said PDM (Pulse Density Modulated) as a signal, representing the desired multiple of pulse areas values;

    means to determine the required length-ratio of positive and negative pulse portions within one sampling period, where said pulse length ratio represents said multiple pulse-area values;

    means to define a set of output pulse-area values, one for each step of said multiple pulse-area values;

    means to control the time of pulse phase changes within one sampling period;

    a pulse generator providing the virtual multi-level output pulses to a power driver, using said pulse length controlled signal;

    means for a Class-D power driver to drive voltage into an output load, controlled by said power driver pulses, typically a Complementary-Pair-Driver or an equivalent circuit; and

    means for an output load as the amplifier'"'"'s output target.

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