Abstract: A control device of a power factor correction circuit disposed in a power supply device that generates a direct-current output voltage from an alternating-current voltage applied to a power supply terminal pair, the power factor correction circuit including an inductor that is disposed between a full-wave rectification circuit that generates a full-wave rectified voltage by carrying out full-wave rectification of the alternating-current voltage and an output interconnect line to which a smoothing capacitor is connected and to which the output voltage is applied, and is inserted between the full-wave rectification circuit and the output interconnect line, and a switching element for controlling an inductor current that flows in the inductor. The control device controls a state of the switching element based on a pulsating voltage obtained by rectifying a voltage between the power supply terminal pair and the full-wave rectification circuit and a feedback voltage according to the output voltage.

Abstract: There is provided an isolated DC/DC converter including a primary side control circuit disposed on the primary side and switching a switching element connected in series with a primary side winding of a power transformer; a secondary side control circuit disposed on the secondary side and generating a control signal including first control information and second control information on the basis of the secondary side voltage; and an insulated transmission circuit transmitting, in an insulated manner, each piece of control information included in the control signal to the primary side control circuit. The primary side control circuit controls a switching frequency of the switching element on the basis of the first control information indicating the frequency of the control signal, and controls a peak value of a primary side current on the basis of the second control information indicating the pulse width of the control signal.

Abstract: A non-isolated buck converter generates an output voltage by stepping down an input voltage obtained by subjecting an alternating-current voltage to full-wave rectification and smoothing, by using a step-down circuit including a switching element, an inductor, and a freewheeling diode. The switching element is disposed between a first terminal and a second terminal. A semiconductor device in charge of switching control operates with a potential at the second terminal as a reference. A control circuit provided in the semiconductor device includes a protecting circuit capable of referring to an evaluation voltage corresponding to a voltage between the first terminal and the second terminal at a sampling timing at which a predetermined period of time has passed from turning off of the switching element, and performing a protecting operation that fixes the switching element to an off state on the basis of the evaluation voltage.

Abstract: There is provided an isolated DC/DC converter including a primary side control circuit disposed on the primary side and switching a switching element connected in series with a primary side winding of a power transformer; a secondary side control circuit disposed on the secondary side and generating a control signal including first control information and second control information on the basis of the secondary side voltage; and an insulated transmission circuit transmitting, in an insulated manner, each piece of control information included in the control signal to the primary side control circuit. The primary side control circuit controls a switching frequency of the switching element on the basis of the first control information indicating the frequency of the control signal, and controls a peak value of a primary side current on the basis of the second control information indicating the pulse width of the control signal.

Abstract: A non-isolated buck converter generates an output voltage by stepping down an input voltage obtained by subjecting an alternating-current voltage to full-wave rectification and smoothing, by using a step-down circuit including a switching element, an inductor, and a freewheeling diode. The switching element is disposed between a first terminal and a second terminal. A semiconductor device in charge of switching control operates with a potential at the second terminal as a reference. A control circuit provided in the semiconductor device includes a protecting circuit capable of referring to an evaluation voltage corresponding to a voltage between the first terminal and the second terminal at a sampling timing at which a predetermined period of time has passed from turning off of the switching element, and performing a protecting operation that fixes the switching element to an off state on the basis of the evaluation voltage.

Abstract: A control device of a power factor correction circuit disposed in a power supply device that generates a direct-current output voltage from an alternating-current voltage applied to a power supply terminal pair, the power factor correction circuit including an inductor that is disposed between a full-wave rectification circuit that generates a full-wave rectified voltage by carrying out full-wave rectification of the alternating-current voltage and an output interconnect line to which a smoothing capacitor is connected and to which the output voltage is applied, and is inserted between the full-wave rectification circuit and the output interconnect line, and a switching element for controlling an inductor current that flows in the inductor. The control device controls a state of the switching element based on a pulsating voltage obtained by rectifying a voltage between the power supply terminal pair and the full-wave rectification circuit and a feedback voltage according to the output voltage.