Adaptive pulse width modulated resonant Class-D converter

  • US 5,986,895 A
  • Filed: 06/05/1998
  • Issued: 11/16/1999
  • Est. Priority Date: 06/05/1998
  • Status: Expired due to Fees
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First Claim
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1. A method for controlling the operation of a Class-D resonant DC-to-DC power converter having a transformer and using first and second alternately turned on switches in a switching cycle to drive a resonant circuit including the primary winding of said transformer so as to produce a high-frequency alternating current in said transformer primary, comprising the steps of:

  • a) turning said first switch on for a first length of time in a first part of each switching cycle, said first length of time being a function of the output voltage of said converter;

    b) turning said second switch on in a second part of each switching cycle, following the turn-off of said first switch; and

    c) turning said second switch off;

    i) a predetermined minimum time after turn-on if the current in said resonant circuit is below a predetermined threshold at said minimum time;

    ii) a predetermined maximum time after turn-on if the current in said resonant circuit remains above said predetermined threshold from said minimum time to said maximum time; and

    iii) at the transition of said resonant circuit current through said predetermined threshold if that transition occurs between said minimum time and said maximum time.

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