×

Constant frequency, zero-voltage-switching converters with resonant switching bridge

  • US 5,594,635 A
  • Filed: 03/30/1993
  • Issued: 01/14/1997
  • Est. Priority Date: 03/30/1993
  • Status: Expired due to Term
First Claim
Patent Images

1. A constant frequency controlled, zero-voltage switched, quasi-resonant converter for receiving power from a DC power source and providing power to a DC load, said converter comprising:

  • switching bridge means for connecting and disconnecting said power from said DC power source to and from said DC load, said switching bridge comprising;

    (a) a resonant inductor having a first end operatively connected to a first node and a second end operatively connected to a second node;

    (b) a first diode having an anode operatively connected to said first node and a cathode operatively connected to a third node;

    (c) a second diode having an anode operatively connected to said second node and a cathode operatively connected to said third node;

    (d) a third diode having an anode operatively connected to a fourth node and a cathode operatively connected to said second node;

    (e) a fourth diode having an anode operatively connected to said fourth node and a cathode operatively connected to said first node;

    (f) first and second active switch means for connecting and disconnecting said DC power source to and from said DC load, said first active switch means operatively connected across said second diode, said second switch means operatively connected across said third diode;

    (g) a first resonant capacitor;

    (h) a second resonant capacitor;

    wherein said first resonant capacitor is operatively connected to said first node such that any voltage change across said first resonant capacitor necessitates a substantially equal voltage change across said fourth diode as represented by ##EQU6## and wherein said second capacitor is operatively connected to said second node such that any voltage change across said second resonant capacitor necessitates a substantially equal voltage change across said third diode as represented by ##EQU7## when said switching bridge is operatively connected to said converter such that any voltage change across said fourth diode necessitates a substantially equal and opposite voltage change across said first diode;

    at least one filtering inductor having first and second ends, said first end operatively connected to said first node, said second end operatively connected to said DC power source;

    at least one filtering capacitor having a first terminal and a second terminal, the first terminal coupled to said third node and the second terminal coupled to said fourth node;

    a timing means for controlling a conduction interval for each of said first active switch means and said second active switch means so that said second active switch means conducts current for a percentage D of a switching period TS, and said first active switch means conducts current only when said second active switch means is turned off such that said first active switch means and said second active switch means and said first diode and said fourth diode turn on and turn off with substantially zero volts across them.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×