Switching power supply device

摘要

A switching power supply device for a ripple control system that can obtain the ripple component with the necessary amplitude without using discrete elements. On capacitor Ci of CR integrator 11, a voltage is generated corresponding to the integration value of the voltage applied to inductor Lo. The ripple voltage generated on capacitor Ci has a waveform similar to that of the ripple current flowing through inductor Lo. The voltage of capacitor Ci is converted into current Iq by voltage/current converter 12, and the current is injected in resistor R3 arranged on the transmission path of output feedback voltage VFB in comparator 2. Resistor R3 generates ripple voltage (Iqxr3) corresponding to the ripple current flowing through inductor Lo. The synthetic voltage of the ripple voltage and output feedback voltage VFB is compared to reference voltage Vref.