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: Provided is a technique of detecting not only a main DC voltage but also an auxiliary DC voltage to protect a main rectifier circuit and an auxiliary rectifier circuit. A main power supply circuit drives a load. A main rectifier circuit receives an AC voltage through a first switch to supply the main power supply circuit with a main DC voltage. The first switch is turned off when an overcurrent flows through the main power supply circuit or the load is an overload for the main power supply circuit. A control circuit is supplied with operating power from an auxiliary power supply circuit. An auxiliary rectifier circuit receives the AC voltage while bypassing the first switch to supply the auxiliary power supply circuit with an auxiliary DC voltage. A DC voltage detection circuit detects the main DC voltage and the auxiliary DC voltage.

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: Provided is a technique of detecting not only a main DC voltage but also an auxiliary DC voltage to protect a main rectifier circuit and an auxiliary rectifier circuit. A main power supply circuit drives a load. A main rectifier circuit receives an AC voltage through a first switch to supply the main power supply circuit with a main DC voltage. The first switch is turned off when an overcurrent flows through the main power supply circuit or the load is an overload for the main power supply circuit. A control circuit is supplied with operating power from an auxiliary power supply circuit. An auxiliary rectifier circuit receives the AC voltage while bypassing the first switch to supply the auxiliary power supply circuit with an auxiliary DC voltage. A DC voltage detection circuit detects the main DC voltage and the auxiliary DC voltage.

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: An indoor unit includes an indoor side switch device which is brought into a closed state at a startup time when operation starts from a standby state. An outdoor unit includes a startup power supply switch device which is brought into a closed state when the indoor side switch device of the indoor unit is brought into the closed state, an operating power supply switch device which is brought into a closed state in operation and is brought into an open state in the standby state, and an outdoor control device. The outdoor control device of the outdoor unit brings the startup power supply switch device into the open state when the operation starts from the standby state and thereafter brings the operating power supply switch device into the closed state after a lapse of a prescribed time.

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: An indoor unit includes an indoor side transmitting and receiving section, a relay which is put in a closed state in a standby state, and an indoor control section which controls the relay on the basis of an output of the indoor side transmitting and receiving section. An outdoor unit includes an outdoor side transmitting and receiving section, and a power circuit. Then, the indoor control section of the indoor unit does not bring the relay into the closed state upon determining that the connection wiring lines which connect the indoor unit with the outdoor unit are miswired on the basis of a reception output of the indoor side transmitting and receiving section when operation starts from a standby state in which the supply of power of the outdoor unit is stopped.

Abstract: An indoor unit includes an indoor side transmitting and receiving section, a relay which is put in a closed state in a standby state, and an indoor control section which controls the relay on the basis of an output of the indoor side transmitting and receiving section. An outdoor unit includes an outdoor side transmitting and receiving section, and a power circuit. Then, the indoor control section of the indoor unit does not bring the relay into the closed state upon determining that the connection wiring lines which connect the indoor unit with the outdoor unit are miswired on the basis of a reception output of the indoor side transmitting and receiving section when operation starts from a standby state in which the supply of power of the outdoor unit is stopped.

Abstract: An indoor unit 10 includes an indoor side transmitting and receiving section 15 which is connected to a signal line L3 and employs a photocoupler, a relay MR10 which is connected between a power line L1 and a signal line L3 and is put in a closed state in a standby state, and an indoor control section 12 which controls the relay MR10 on the basis of an output of the indoor side transmitting and receiving section 15. An outdoor unit 20 includes an outdoor side transmitting and receiving section 25 which is connected to the signal line L3 and employs a photocoupler, and a power circuit 23 supplied with a power from two power lines L1 and L2.