Step-up/down DC-DC converter and switching control circuit

摘要

A step-up/down DC-DC converter and switching control circuit are described. According to one implementation, a switching control circuit generates on/off signals of a first switching device supplying a current to a voltage conversion inductor of a step-up/down DC-DC converter and a second switching device receiving a current from the inductor. The switching control circuit includes an error amplifier circuit, an inverter amplifier circuit, a waveform generator circuit, a first voltage comparator circuit, a second voltage comparator circuit, and a voltage generator circuit. An inverting reference voltage supplied to the inverting amplifier circuit is set to an electric potential so as not to fall below a highest electric potential of triangle waves supplied to the first and second voltage comparator circuits.