Abstract: A multiphase power converter includes one or both of a phase control circuit and a valley switching locking circuit. The phase control circuit measures a phase difference between a first phase circuit and a second phase circuit and varies an on-time of a drive switch of the second phase circuit to produce and maintain a predetermined phase difference between the first phase circuit and the second phase circuit. When the multiphase power converter is operating in a discontinuous mode of operation, the valley switching locking circuit counts the number of zero crossings of an input current of the first phase circuit and blocks a second zero crossing detection signal from a waveform generator (i.e., PWM driver) associated with the second phase circuit until an input current of the second phase circuit has as many zero crossings as that of the first phase circuit input current.

Abstract: A power converter operable to draw an input current that is in phase with an input voltage of the power converter and proportional to a voltage of the input voltage of the power converter includes a drive switch, a waveform generator, and a current shaping circuit. The drive switch is connected between an input inductor and ground and draws current through the input inductor when turned on. The current shaping circuit provides 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. 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.

Abstract: A multiphase power converter includes one or both of a phase control circuit and a valley switching locking circuit. The phase control circuit measures a phase difference between a first phase circuit and a second phase circuit and varies an on-time of a drive switch of the second phase circuit to produce and maintain a predetermined phase difference between the first phase circuit and the second phase circuit. When the multiphase power converter is operating in a discontinuous mode of operation, the valley switching locking circuit counts the number of zero crossings of an input current of the first phase circuit and blocks a second zero crossing detection signal from a waveform generator (i.e., PWM driver) associated with the second phase circuit until an input current of the second phase circuit has as many zero crossings as that of the first phase circuit input current.

Abstract: A power converter operable to draw an input current that is in phase with an input voltage of the power converter and proportional to a voltage of the input voltage of the power converter includes a drive switch, a waveform generator, and a current shaping circuit. The drive switch is connected between an input inductor and ground and draws current through the input inductor when turned on. The current shaping circuit provides 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. 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.

Abstract: A current sensor is provided that employs a primary winding that carries the current to be measured, and a secondary winding that controls the flux inside the magnetic core, provides a sample of the primary current, and also helps to control the flux at small primary currents and to saturate the transformer. An auxiliary winding is optionally used to control the flux in order to simplify control of the sensor. By periodically applying a certain voltage at the secondary winding, the transformer core is forced out of saturation, and a sample of the primary current is taken by a sensing circuit that may include a sample-and-hold circuit and an analog-to-digital converter. A control circuit is employed to control the currents flowing in the secondary winding and optional auxiliary winding and to manage the sensing circuit.

Abstract: A current sensor is provided that employs a primary winding that carries the current to be measured, and a secondary winding that controls the flux inside the magnetic core, provides a sample of the primary current, and also helps to control the flux at small primary currents and to saturate the transformer. An auxiliary winding is optionally used to control the flux in order to simplify control of the sensor. By periodically applying a certain voltage at the secondary winding, the transformer core is forced out of saturation, and a sample of the primary current is taken by a sensing circuit that may include a sample-and-hold circuit and an analog-to-digital converter. A control circuit is employed to control the currents flowing in the secondary winding and optional auxiliary winding and to manage the sensing circuit.