Synchronous rectifier that is impervious to reverse feed

Synchronous rectifier, comprising a transformer with a primary winding which is supplied on an alternating basis with current from a direct-current source by means of a switch that is controlled by an oscillator, the transformer having a first secondary winding with first and second ends, further comprising a first MOSFET and a second MOSFET which are connected into the circuit on an alternating basis in time with the oscillator, the first MOSFET functioning as a rectifier diode and the second MOSFET functioning as a recovery diode, a drain electrode of the first MOSFET being joined with the first end of the first secondary winding and with a first output of the synchronous rectifier by means of a storage choke, a drain electrode of the second MOSFET supplying current to the second end of the first secondary winding, the source electrodes of first and second MOSFETs being joined by a line with a second output of the synchronous rectifier, and the first and second outputs being joined by means of a storage and smoothing capacitor, the synchronous rectifier further comprising:

• the transformer having a second secondary winding with first and second ends, the first end of the second secondary winding having the same polarity the as first end of the first secondary winding;
• a control device a first connection of the control device being connected with the first end of the second secondary winding, a second connection of the control device being connected with the second end of the second secondary winding, a third connection of the control device being connected with the first end of the first secondary winding, a fourth connection of the control device being connected with the second end of the first secondary winding, a fifth connection of the control device being connected to the line, a sixth connection of the control device being connected to a gate electrode of the first MOSFET, and a seventh connection of the control device being connected to a gate electrode of the second MOSFET,
• the control device contains means for the determination of whether a voltage is being induced through the first and second secondary windings to determine whether the synchronous rectifier is working, and means for blocking the first and second MOSFETs upon determining that the synchronous rectifier is not working, whereupon the first and second MOSFETs will continue to carry out their diode function by means of first and second substrate diodes.