Abstract: Bridgeless PFC converters. Example embodiments are methods of operating a power converter including operating the power converter during a positive half-line cycle of an alternating current (AC) source by: charging an inductance through a low-side switch with a first charging current having a first polarity; measuring the first charging current using a low-side current transformer (CT), while shorting a secondary winding of a high-side CT; and discharging the inductance through a high-side switch with a first discharging current having the first polarity. Operating the power converter during a negative half-line cycle of the AC source by: charging the inductance through the high-side switch with a second charging current having a second polarity; measuring the second charging current using the high-side CT, while shorting a secondary winding of the low-side CT; and discharging the inductance through the low-side switch with a second discharging current having the second polarity.

Abstract: Bridgeless PFC converters. At least some example embodiments are methods of operating a power converter, including operating the power converter during a positive half-line cycle of a frequency of an alternating current (AC) source by: charging a primary winding of a multi-winding boost inductor with a charging current having a first polarity; and then discharging the primary winding; sensing a falling edge of a voltage at a switch node by way of a secondary winding of the multi-winding boost inductor; and triggering a subsequent charging of the primary winding during the positive half-line cycle based on the falling edge. Operating the power converter during a negative half-line cycle of the line frequency by: sensing a rising edge of the voltage at the switch node by way of the secondary winding; and triggering a subsequent charging of the primary winding.

Abstract: Bridgeless PFC converters. Example embodiments are methods of operating a power converter including operating the power converter during a positive half-line cycle of an alternating current (AC) source by: charging an inductance through a low-side switch with a first charging current having a first polarity; measuring the first charging current using a low-side current transformer (CT), while shorting a secondary winding of a high-side CT; and discharging the inductance through a high-side switch with a first discharging current having the first polarity. Operating the power converter during a negative half-line cycle of the AC source by: charging the inductance through the high-side switch with a second charging current having a second polarity; measuring the second charging current using the high-side CT, while shorting a secondary winding of the low-side CT; and discharging the inductance through the low-side switch with a second discharging current having the second polarity.

Abstract: Bridgeless PFC converters. At least some example embodiments are methods of operating a power converter, including operating the power converter during a positive half-line cycle of a frequency of an alternating current (AC) source by: charging a primary winding of a multi-winding boost inductor with a charging current having a first polarity; and then discharging the primary winding; sensing a falling edge of a voltage at a switch node by way of a secondary winding of the multi-winding boost inductor; and triggering a subsequent charging of the primary winding during the positive half-line cycle based on the falling edge. Operating the power converter during a negative half-line cycle of the line frequency by: sensing a rising edge of the voltage at the switch node by way of the secondary winding; and triggering a subsequent charging of the primary winding.

Abstract: In one form, a bridgeless AC-DC converter includes a totem pole network having a first input adapted to be coupled to a second terminal of an AC voltage source, a second input adapted to be coupled to a first terminal of the AC voltage source through an inductor, an output terminal for providing an output voltage, and a return terminal, an output capacitor coupled between the output terminal and an output ground terminal, a sense element coupled between the return terminal and the output ground terminal, and a controller circuit coupled to the return terminal of the totem pole network. The controller circuit modulates an on time of an active switch in the totem pole network on a cycle-by-cycle basis by shortening the on time corresponding to an amount of time a current sense signal derived from a current through the sense element exceeds a current limit threshold.