If all the components are ideal, no power can be dissipated, and all input power is transferred to the output. This fraction is usually modulated by a feedback loop to regulate the output voltage.ĭue to the current path thru D1, the output current is higher than the input current. The fraction of the time the switch is closed regulates the overall output current. The switch opens and closes rapidly to add current to the inductor when closed and causes the inductor current to ramp down when open. Since the voltage accross the inductor is now negative, the current in it decreases. When the switch is opened, the instantaneous inductor current must continue to flow. When the switch is closed, current builds up in the inductor. Therefore I'll only explain the general concept briefly. There is much written about buck converters out there, and the term "buck converter" should be a useful search term. Getting 95% requires someone that knows what they are doing really applying themselves to the problem. You have to wake up and take it seriously to get over 90%. For a linear regulator (current out) = (current in) - losses.īuck converters up to 85% or so efficient are relatively easy to make yourself. For a buck converter, (watts out) = (watts in) - losses. The most efficient way to create a lower voltage at higher current from a higher voltage at lower current is a type of switching power supply called a buck converter.
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