Method for driving an electronic switch in a power converter circuit and control circuit

An apparatus comprising:

• a controller operative to:
• drive a switch, the switch coupled to an inductor in a power converter, the switch being driven during successive drive cycles, each of which includes an ON-time and an OFF-time of controlling the switch;
• control a magnitude of an ON-time duration of the switch in a second drive cycle depending on a feedback signal, the second drive cycle occurring subsequent to a first drive cycle of controlling the ON-time duration of the switch;
• and
• wherein control of the magnitude of the ON-time duration in the second drive cycle comprises:
• i) adjustment of a first on-time portion, TON1, of the ON-time duration in the second drive cycle based on the feedback signal, ii) determination of a duration of a delay time between a demagnetization time instance in the first drive cycle and an end of the first drive cycle, and iii) adjustment of a second on-time portion, TON2, of the ON-time duration in the second drive cycle based on the duration of the delay time.

A method comprising:

• i) during a first control cycle:
• controlling operation of a switch coupled to a primary winding of a transformer, the primary winding inductively coupled to a secondary winding of the transformer, activation of the switch storing energy in the transformer, the energy from the transformer producing output current from the secondary winding during deactivation of the switch;
• and
• ii) during a second control cycle following the first control cycle:
• controlling a magnitude of an ON-time duration of activating the switch coupled to the primary winding of the transformer based on a time delay between a first time instance in which the transformer becomes demagnetized in the first control cycle during the deactivation of the switch and a second time instance of activating the switch at a beginning of the second control cycle.