Abstract: When power consumption of a load is smaller than a first threshold, a switch element of each of one or more circuits is made nonconductive to supply power from all of the one or more circuits to the load. When the power consumption of the load is larger than the first threshold, the switch element of at least one of the one or more circuits is made intermittently conductive to supply power from all of the one or more circuits to the load.

Abstract: A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.

Abstract: When power consumption of a load is smaller than a first threshold, a switch element of each of one or more circuits is made nonconductive to supply power from all of the one or more circuits to the load. When the power consumption of the load is larger than the first threshold, the switch element of at least one of the one or more circuits is made intermittently conductive to supply power from all of the one or more circuits to the load.

Abstract: A reactor, a diode, and a switching element connected to a path constitute a booster circuit, and another reactor, another diode, and another switching element connected to another path constitute another booster circuit. The booster circuits also function as a power factor correction circuit for correcting a power factor of the input side. Swing chokes are adopted as the reactors.

Abstract: A circuit includes a reactor, a diode, and a switching element. The reactor and the diode are connected in series with each other on a power supply line. The switching element is provided between a power supply line and a point between the reactor and the diode. A circuit includes a reactor, a diode, and a switching element. The reactor and the diode are connected in series with each other on a power supply line. The switching element is provided between the power supply line and a point between the reactor and the diode. Characteristics of at least any of the reactors, the switching elements, and the diodes are different from each other.

Abstract: A master transistor and a slave transistor are both insulated gate bipolar transistors. A slave diode is connected in anti-parallel to the slave transistor. The master transistor is brought into conduction if a current flowing in a master reactor becomes zero, and is brought into nonconduction after elapse of a first period. The slave transistor is brought into conduction subject to elapse of a certain period after the master transistor is brought into conduction that is one of conditions for conduction of the slave transistor, and is brought into nonconduction after elapse of a second period shorter than the first period. The certain period is shorter than a period from when the master transistor is brought into conduction until when the master transistor is brought into conduction again.

Abstract: A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.

Abstract: A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.

Abstract: A reactor, a diode, and a switching element connected to a path constitute a booster circuit, and another reactor, another diode, and another switching element connected to another path constitute another booster circuit. The booster circuits also function as a power factor correction circuit for correcting a power factor of the input side. Swing chokes are adopted as the reactors.

Abstract: A circuit includes a reactor, a diode, and a switching element. The reactor and the diode are connected in series with each other on a power supply line. The switching element is provided between a power supply line and a point between the reactor and the diode. A circuit includes a reactor, a diode, and a switching element. The reactor and the diode are connected in series with each other on a power supply line. The switching element is provided between the power supply line and a point between the reactor and the diode. Characteristics of at least any of the reactors, the switching elements, and the diodes are different from each other.

Abstract: A master transistor and a slave transistor are both insulated gate bipolar transistors. A slave diode is connected in anti-parallel to the slave transistor. The master transistor is brought into conduction if a current flowing in a master reactor becomes zero, and is brought into nonconduction after elapse of a first period. The slave transistor is brought into conduction subject to elapse of a certain period after the master transistor is brought into conduction that is one of conditions for conduction of the slave transistor, and is brought into nonconduction after elapse of a second period shorter than the first period. The certain period is shorter than a period from when the master transistor is brought into conduction until when the master transistor is brought into conduction again.