A power converter (920; 980) operable to draw an input current that is in phase with an input voltage of the power converter and substantially proportional to a voltage of the input voltage of the power converter, the power converter comprising: an input inductor; a drive switch connected between the input inductor and ground, the drive switch operable to draw current through the input inductor when turned on; a waveform generator operable to selectively turn the drive switch on and off to cycle the drive switch; and a current shaping circuit operable to provide an on-time of the drive switch for a next cycle of the drive switch as a function of an input current decay time, a switching period of the waveform generator, and an output voltage of the power converter, wherein the waveform generator is responsive to the on-time provided by the current shaping circuit for selectively turning the drive switch on and off to cycle the drive switch as a function of the received on-time, characterized in that a voltage control loop is operable to provide a default on-time (T ON) of the drive switch as a function of the output voltage of the power converter, wherein the default on-time of the drive switch is a predetermined value corresponding to the output voltage of the power converter, and in that the current shaping circuit comprises a first multiplier operable to multiply the default on-time (T ON) of the drive switch provided by the voltage control loop by the switching period (T SW) of the waveform generator to obtain a first product, a second multiplier operable to multiply the first product by 4 to obtain a second product, a third multiplier operable to multiply the input current decay time (T 2) by the input current decay time (T 2) to obtain a third product, an adder operable to add the second product to the third product to obtain a first sum, a square root circuit operable to determine the square root of the first sum to obtain a root, a subtractor operable to deduct the input current decay time from the root to obtain a difference, and a divider operable to divide the difference by 2 to obtain an effective on-time T ON-EFF of the drive switch for the next cycle, and and in that the current shaping circuit provides the effective on-time T ON-EFF of the drive switch for the next cycle to the waveform generator as the on-time of the drive switch for the next cycle. an input inductor; a drive switch connected between the input inductor and ground, the drive switch operable to draw current through the input inductor when turned on; a waveform generator operable to selectively turn the drive switch on and off to cycle the drive switch; and a current shaping circuit operable to provide an on-time of the drive switch for a next cycle of the drive switch as a function of an input current decay time, a switching period of the waveform generator, and an output voltage of the power converter, wherein the waveform generator is responsive to the on-time provided by the current shaping circuit for selectively turning the drive switch on and off to cycle the drive switch as a function of the received on-time, characterized in that a voltage control loop is operable to provide a default on-time (T ON) of the drive switch as a function of the output voltage of the power converter, wherein the default on-time of the drive switch is a predetermined value corresponding to the output voltage of the power converter, and in that the current shaping circuit comprises a first multiplier operable to multiply the default on-time (T ON) of the drive switch provided by the voltage control loop by the switching period (T SW) of the waveform generator to obtain a first product, a second multiplier operable to multiply the first product by 4 to obtain a second product, a third multiplier operable to multiply the input current decay time (T 2) by the input current decay time (T 2) to obtain a third product, an adder operable to add the second product to the third product to obtain a first sum, a square root circuit operable to determine the square root of the first sum to obtain a root, a subtractor operable to deduct the input current decay time from the root to obtain a difference, and a divider operable to divide the difference by 2 to obtain an effective on-time T ON-EFF of the drive switch for the next cycle, and and in that the current shaping circuit provides the effective on-time T ON-EFF of the drive switch for the next cycle to the waveform generator as the on-time of the drive switch for the next cycle.