Abstract: A switch circuit comprising a semiconductor switch and an inverse-parallel diode is connected between a main electricity storage unit 4 and a primary winding 142P of an insulating transformer 142 and a switch circuit including a semiconductor switch and a diode is connected in inverse-parallel between a secondary winding 142S of the insulating transformer 142 and an auxiliary electricity storage unit 10. The switch circuits are controlled on/off, whereby power is supplied from the main electricity storage unit 4 to the auxiliary electricity storage unit 10 or from the auxiliary electricity storage unit 10 to the main electricity storage unit 4 for charging the electricity storage unit 10 or 4.

Abstract: A smoothing circuit for a switching power supply is formed of a combination of a reactor and a capacitor having a small equivalent internal resistance, and a MOSFET connected in series to the capacitor. The MOSFET is turned on by an output voltage of the smoothing circuit and has an ON-state resistance compensating for an equivalent internal resistance of the capacitor.

Abstract: In a smoothing circuit for a switching power supply having a reactor and a capacitor, the circuit includes a resistor connected in series to the capacitor, a MOSFET connected parallel to the resistor, and a control circuit for turning the MOSFET on only when the voltage at both ends of the resistor increases or decreases to reach reference voltages. Thus, the output waveform is changed from a triangular wave to a sine wave in order to reduce the harmonic components contained in the output ripple. An output noise is reduced stably without reducing efficiency.

Abstract: The present invention provides a snubber circuit for a switching power supply that generates rectified direct current power from an inductive load cyclically connected and disconnected by two switching means fed by a direct current power supply. To reduce turn-on and turn-off loss of the switching means and increase switching frequency by reducing power loss in the snubber circuit, the snubber circuit according to the present invention absorbs counter-electromotive force generated during turn-off of the switching means. Turn-on loss of the switching means is reduced because a current from the switching means does not flow through the snubber circuit when the switching means are turned on.

Abstract: A temperature-adjustable water supply system used for supplying an appropriate temperature water to a water-using object. The system comprises a mixing device coupled to a hot water supply passage and a cold water supply passage for respectively introducing hot water and cold water thereinto and coupled to a water mixture supply passage for supplying the mixture of the hot water and cold water toward said water-using object. The mixing device includes a flow rate adjusting valve assembly for adjusting the mixture ratio of the hot water and the cold water discharged into the water mixture supply passage. A temperature sensor is provided so as to sense the temperature of the water mixture and a temperature setter for setting a target temperature. Also included in the system is a control unit which calculates a temperature deviation on the basis of the temperature of the mixture sensed by the temperature sensor and the target temperature set by the temperature setter.