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Power source using high-frequency phase control

  • US 4,772,994 A
  • Filed: 09/10/1987
  • Issued: 09/20/1988
  • Est. Priority Date: 09/10/1987
  • Status: Expired due to Term
First Claim
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1. A power source of the type using a high-frequency phase control, which comprises:

  • a high-frequency transformer having a primary winding and a secondary winding,first and second switch means each connected at one terminal thereof to the opposite terminals of the primary winding of said high-frequency transformer and each connected at the other terminal thereof to the other, with the common point of connection of said first and second switching means being adapted for connection to a constant polarity source of voltage, and with there being a center tap in said primary winding of said high-frequency transformer adapted for connection to a reference source of voltage,third and fourth switch means each connected at one terminal thereof to the opposite terminals of the secondary winding of said high-frequency transformer and each connected at the other terminal thereof to the other,a reactor connected between the common point of connection of said third and fourth switch means and one of a pair of output terminals,a center tap of said secondary winding of said high-frequency transformer connected to the other of the pair of output terminals,a controlling device for effecting ON-OFF switching control alternately of said first and second switch means and, at the same time, effecting ON-OFF switching control alternately of said third and fourth switch means with a selected phase difference with reference to the switching of said first and second switch means, said controlling device comprising;

    an error amplifier for generating a deviation signal representing any deviation from a reference signal of any output voltage appearing between said pair of output terminals,a flipflop for generating a first rectangular wave controlling signal possessing an amply high frequency as compared with the frequency of said reference signal and exhibiting a duty ratio of 1/2, and a secondd rectangular wave controlling signal of a reverse phase relative to the phase of said first rectangular wave controlling signal,means for generating a triangular wave signal which is synchronized to the first and second rectangular wave controlling signals,a comparator for comparing the triangular wave and the deviation signal to generate a preliminary rectangular wave signal in response to the difference in their amplitude with a duty ratio depending on the amount of this difference,a logic circuit being supplied with the preliminary rectangular wave signal and one of the first and second rectangular wave controlling signals to provide third and fourth rectangular wave controlling signals of opposite phase and with a phase differing from that of the first and second rectangular wave controlling signal depending on the duty ratio of the preliminary rectangular signal, andmeans for effecting ON-OFF control of said first through fourth switch means in accordance with said first through fourth rectangular wave controlling signals.

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