US 11,658,581 B1
Power converter with adjustable output voltage
Chia-An Yeh, New Taipei (TW)
Assigned to Acbel Polytech Inc., New Taipei (TW)
Filed by ACBEL POLYTECH INC., New Taipei (TW)
Filed on Feb. 15, 2022, as Appl. No. 17/671,988.
Int. Cl. H02M 3/335 (2006.01)
CPC H02M 3/33576 (2013.01) [H02M 3/33571 (2021.05); H02M 3/33592 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A power converter with an adjustable voltage output, comprising:
an isolation DC/DC transformer having a primary coil and a secondary coil;
a primary side circuit connected to the primary coil of the isolation DC/DC transformer for transmitting an input AC power to the primary coil;
a secondary side circuit connected to the secondary coil of the isolation DC/DC transformer and comprising a first output loop and a second output loop;
a mode switch connected to the first output loop;
wherein when the mode switch turns off, the first output loop is open and the second output loop outputs a first output voltage; when the mode switch turns on, the second output loop outputs a second output voltage higher than the first output voltage;
wherein the secondary coil is a central-tapped coil having a first end, a second end and a central-tapped end;
the secondary side circuit includes a first rectifying switch and a second rectifying switch, wherein the first output loop is formed by a configuration that the first rectifying switch is connected to the first end of the secondary coil and connected to one end of the mode switch, while the other end of the mode switch is connected to a ground;
the second output loop is formed by a configuration that the second rectifying switch is connected between the second end of the secondary coil and the ground;
the central-tapped end of the secondary coil is connected to an output capacitor;
the first rectifying switch and the mode switch are NMOS power transistors with their sources connected together; and
the primary side circuit comprises:
an inductor connected in parallel to the primary coil;
a resonant capacitor connected between an input DC power port of an input DC power and a dotted end of the primary coil;
a first switch having
a first end connected to the input DC power port of the input DC power; and
a second end connected to a non-dotted end of the primary coil; and
a second switch connected between the non-dotted end of the primary coil and the ground.