Abstract: An apparatus includes a first winding and a first switch connected in series between an input terminal and ground, a second winding magnetically coupled to the first winding and coupled to an output terminal through a second switch, a third winding magnetically coupled to the first winding and connected in series with a fourth switch, a fourth winding magnetically coupled to the first winding and connected in series with a third switch, and an energy storage device connected between a common node of the third winding and the fourth winding, and ground.

Abstract: An apparatus includes a first winding and a first switch connected in series between an input terminal and ground, a second winding magnetically coupled to the first winding and coupled to an output terminal through a second switch, a third winding magnetically coupled to the first winding and connected in series with a fourth switch, a fourth winding magnetically coupled to the first winding and connected in series with a third switch, and an energy storage device connected between a common node of the third winding and the fourth winding, and ground.

Abstract: A method includes detecting a first current flowing through a first clamping device coupled to a gate of a power switch, determining whether an inductor current reduces to zero based upon a first comparison between the first current and a first predetermined current level, and after determining the inductor current reduces to zero, determining whether a drain voltage of the power switch enters a valley of a resonant ringing based upon a second comparison between the first current and the first predetermined current level.

Abstract: A method includes comparing a ramp signal with an output signal of an error amplifier to determine an initial turn-on time of a boost converter, generating a turn-on time of the boost converter through multiplying the initial turn-on time by a predetermined constant greater than or equal to 1, and maintaining a switching frequency of the boost converter substantially constant through varying a value of the predetermined constant.

Abstract: A method includes detecting a first current flowing through a first clamping device coupled to a gate of a power switch, determining whether an inductor current reduces to zero based upon a first comparison between the first current and a first predetermined current level, and after determining the inductor current reduces to zero, determining whether a drain voltage of the power switch enters a valley of a resonant ringing based upon a second comparison between the first current and the first predetermined current level.

Abstract: A method includes comparing a ramp signal with an output signal of an error amplifier to determine an initial turn-on time of a boost converter, generating a turn-on time of the boost converter through multiplying the initial turn-on time by a predetermined constant greater than or equal to 1, and maintaining a switching frequency of the boost converter substantially constant through varying a value of the predetermined constant.