A multiphase power converter comprising: a first phase circuit comprising a first input inductor having a first end and a second end, wherein the first end is connected to a power source, a first drive switch connected between the second end of the first input inductor and ground, and a first output diode having an anode connected to the second end of the first input inductor and a cathode connected to an output of the power converter; a second phase circuit comprising a second input inductor having a first end and a second end, wherein the first end is connected to the power source, a second drive switch connected between the second end of the second input inductor and ground, and a second output diode having an anode connected to the second end of the second input inductor and a cathode connected to the output of the power converter; and a controller operable to selectively turn the first drive switch of the first phase circuit on and off to cycle the first drive switch of the first phase circuit and to selectively turn the second drive switch of the second phase circuit on and off to cycle the second drive switch of the second phase circuit, characterized in that the controller comprises a valley switching locking circuit comprising a first counter operable to count zero crossings of a first zero crossing signal in a switching period of the first drive switch, wherein the first zero crossing signal is associated with an input current of the first phase circuit, a second counter operable to count zero crossings of a second zero crossing signal in a switching period of the second drive switch, wherein the second zero crossing signal is associated with an input current of the second phase circuit, and a comparator operable to block the second zero crossing signal if the count of zero crossings of the second zero crossing signal in the switching period of the second drive switch is less than the count of zero crossings of the first zero crossing signal in the switching period of the first drive switch, wherein the controller turns the first drive switch of the first phase circuit on and off as a function of the output signals from the valley switch locking circuit, and turns the second drive switch of the second phase circuit on and off as a function of the output signals from the valley switching locking circuit when the second zero crossing signal is not blocked by the comparator. a first phase circuit comprising a first input inductor having a first end and a second end, wherein the first end is connected to a power source, a first drive switch connected between the second end of the first input inductor and ground, and a first output diode having an anode connected to the second end of the first input inductor and a cathode connected to an output of the power converter; a second phase circuit comprising a second input inductor having a first end and a second end, wherein the first end is connected to the power source, a second drive switch connected between the second end of the second input inductor and ground, and a second output diode having an anode connected to the second end of the second input inductor and a cathode connected to the output of the power converter; and a controller operable to selectively turn the first drive switch of the first phase circuit on and off to cycle the first drive switch of the first phase circuit and to selectively turn the second drive switch of the second phase circuit on and off to cycle the second drive switch of the second phase circuit, characterized in that the controller comprises a valley switching locking circuit comprising a first counter operable to count zero crossings of a first zero crossing signal in a switching period of the first drive switch, wherein the first zero crossing signal is associated with an input current of the first phase circuit, a second counter operable to count zero crossings of a second zero crossing signal in a switching period of the second drive switch, wherein the second zero crossing signal is associated with an input current of the second phase circuit, and a comparator operable to block the second zero crossing signal if the count of zero crossings of the second zero crossing signal in the switching period of the second drive switch is less than the count of zero crossings of the first zero crossing signal in the switching period of the first drive switch, wherein the controller turns the first drive switch of the first phase circuit on and off as a function of the output signals from the valley switch locking circuit, and turns the second drive switch of the second phase circuit on and off as a function of the output signals from the valley switching locking circuit when the second zero crossing signal is not blocked by the comparator.