Resonant rectifying device, control method and apparatus for resonant rectifying

A control method for controlling a resonant rectifying device, wherein the resonant rectifying device includes:

• a transformer having a primary winding and a secondary winding;
• a primary-side circuit coupled to the primary winding of the transformer, the primary-side circuit including:
• a first field effect transistor (FET) and a second FET coupled in series between a voltage source and a ground;
• a capacitor, a first side of the capacitor being coupled to a point between the first and the second FETs;
• and
• an inductor, a first end of the inductor being coupled to one end of the primary winding and to a second side of the capacitor, and a second end of the inductor being coupled to the ground, wherein the inductor is a first inductor, and the primary-side circuit further includes a second inductor coupled in series between the capacitor and the first inductor;
• and
• a secondary-side circuit coupled to the secondary winding of the transformer, the secondary-side circuit includes:
• a third FET, a first end of the third FET being coupled to a first end of the secondary winding;
• and
• a fourth FET, a first end of the fourth FET being coupled to a second end of the secondary winding;
• wherein a second end of the third FET and a second end of the fourth FET are coupled to each other, and are coupled to an output terminal of the secondary-side circuit;
• the method comprising:
• during a first time segment of an operating period of the resonant rectifying device:
• controlling the first FET to turn on;
• controlling the third FET to turn on after an on-delay time after the first FET is turned on;
• controlling the third FET to turn off;
• and
• controlling the first FET to turn off after an off-delay time after the third FET is turned off;
• during a second time segment of the operating period after the first time segment:
• controlling the first FET, the second FET, the third FET, and the fourth FET to keep off;
• during a third time segment of the operating period after the second time segment:
• controlling the first FET, the second FET, the third FET, and the fourth FET to keep off;
• during a fourth time segment of the operating period after the third time segment:
• controlling the second FET to turn on;
• controlling the fourth FET to turn on after the on-delay time after the second FET is turned on;
• controlling the fourth FET to turn off;
• and
• controlling the second FET to turn off after the off-delay time after the fourth FET is turned off;
• and
• during a fifth time segment of the operating period after the fourth time segment:
• controlling the first FET, the second FET, the third FET, and the fourth FET to keep off.

A resonant rectifying device, comprising:

• a transformer having a primary winding and a secondary winding;
• a primary-side circuit coupled to the primary winding of the transformer, the primary-side circuit including:
• a first field effect transistor (FET) and a second FET coupled in series between a voltage source and a ground;
• a capacitor, a first side of the capacitor being coupled to a point between the first and the second FETs;
• and
• an inductor, a first end of the inductor being coupled to one end of the primary winding and to a second side of the capacitor, and a second end of the inductor being coupled to the ground;
• and
• a secondary-side circuit coupled to the secondary winding of the transformer, the secondary-side circuit includes:
• a third FET, a first end of the third FET being coupled to a first end of the secondary winding;
• and
• a fourth FET, a first end of the fourth FET being coupled to a second end of the secondary winding,
• wherein a second end of the third FET and a second end of the fourth FET are coupled to each other, and are coupled to an output terminal of the secondary-side circuit;
• and
• wherein when the resonant rectifying device is in a light-load mode or an idle mode, the resonant rectifying device adopts a frequency modulation (FM) control mode, and when the resonant rectifying device is in a full-load mode, the resonant rectifying device adopts a pulse width modulation (PWM) control mode.