Invention Grant
US08687821B2 Plop-free amplifier 有权
无波动放大器

  • Patent Title: Plop-free amplifier
  • Patent Title (中): 无波动放大器
  • Application No.: US12945505
    Application Date: 2010-11-12
  • Publication No.: US08687821B2
    Publication Date: 2014-04-01
  • Inventor: Han Martijn Schuurmans
  • Applicant: Han Martijn Schuurmans
  • Applicant Address: NL Eindhoven
  • Assignee: NXP B.V.
  • Current Assignee: NXP B.V.
  • Current Assignee Address: NL Eindhoven
  • Priority: EP09176061 20091116
  • Main IPC: H04B15/00
  • IPC: H04B15/00
Plop-free amplifier
Abstract:
An amplifier is disclosed, wherein the output stage is split between a primary output stage and a secondary stage. To minimize or eliminate any audible plop when the amplifier is switched on, the primary stage is connected, and the second stage is gradually connected using a switch. The gradual connection can be by means of varying the pulse-density of a pulse wave modulation on the switch, from fully open (0% pulse-density) to fully closed (100%). The inverse process can minimize or eliminate plop during switch-off. Separate feedback loops are switchable, from the primary and secondary stages; in a DC-coupled embodiment, the feedback loop from the secondary stage may include DC-offset cancelling circuitry, to both reduce or eliminate the plop and avoid and DC-offset current through the speaker.
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