How to Apply DC-to-DC Step-Down (Buck) Regulators Successfully
Ken Marasco · 2011
Figure 1 shows a typical low-power system operating with a Li-Ion battery. The battery’s usable output varies from 3 V to 4.2V, while the ICs require 0.8 V, 1.8 V, 2.5 V, and 2.8 V. A simple way to reduce the battery voltage to a lower dc voltage is to use a lowdropout regulator (LDO). Unfortunately, power not delivered to the load is lost as heat, making LDOs inefficient when VIN is much greater than VOUT. A popular alternative, the switching converter, alternately stores energy in an inductor’s magnetic field, and releases the energy to the load at a different voltage. Its reduced losses make it a better choice for high efficiency. Buck, or step-down