Charger, dc/dc converter including that charger, and control circuit thereof

Abstract

A new charger wherein a reference voltage can be set therein. The charger charges a secondary battery via a DC/DC converter that has an arrangement in which a fuel cell, a solar cell or the like having a relatively large output impedance during power supply is used as an input source (Vfc) and an input power is kept constant. The secondary battery (B) is connected to a control circuit (), and a constant power reference voltage control circuit () is connected between the current control circuit and an input of the charger. When the output of the charger is drooping, the constant power reference voltage control circuit reduces the reference voltage to increase the power to be supplied, thereby providing a constant power at the voltage as defined by the output voltage stabilization control of the charger. When the input power of the charger is excessive, the constant power reference voltage control circuit increases the reference voltage to set a reference value corresponding to the power to be supplied.