Patents Represented by Attorney Dana LeMoine
  • Patent number: 5886572
    Abstract: A method and apparatus for efficient power amplification with low distortion includes an envelope detector (220), a difference amplifier (130), an envelope amplifier (270), and a power amplifier (260). A feedback path is provided from the output through a second envelope detector (120) to the difference amplifier (130). The feedback circuit operates on the bandwidth of the envelope of the RF signal rather than at the RF bandwidth. An envelope amplifier (270) includes a difference amplifier (272), a pulsewidth modulator (275), a driver (280), switching transistors (285), a low pass filter (290), and a voltage scaler (292). A feedback path within the envelope amplifier reduces the time delay introduced by low pass filter (290). The combined feedback loops work together to reduce distortion and lower intermodulation products.
    Type: Grant
    Filed: July 25, 1997
    Date of Patent: March 23, 1999
    Assignee: Motorola, Inc.
    Inventors: Ronald Gene Myers, Bernard Eugene Sigmon, Robert Michael Jackson