Inductorless Switching Regulator Circuit
Posted on Apr 30, 2012 3510
In conventional applications, switching-regulator ICs regulate VQVT by controlling the current through an external inductor. The IC in A, however, driving a diode-capacitor network in place of the inductor, offers comparable performance for small loads. The network can double, triple, or quadruple the input voltage. Feedback from the RI/R2 voltage divider enables IC1 to set the regulated-output, level. (As shown, the circuit derives 12 V from a 5- to 12-V input and provides as much as 2 mA of output current).
Adding a noninverting MOS driver (B) boosts the available output current to 20 mA. Substituting the diode-capacitor network shown for an inductor allows this switching-regulator IC to deliver 2 mA at comparable line and load regulation, with somewhat reduced efficiency.