12V - 48V @ 1A
A switched-inductor type boost converter has multiple inductors that are charged in parallel but discharged in series, thereby putting multiple boost inductors in series to the input power supply. The two diodes above and below the inductors enable parallel charging of the inductors when the MOSFET is on and the two diodes in series with the inductors put them in series to the input when the MOSFET is off. This results in an increased "boost" for the same duty cycle compared to a single inductor type boost converter.
The output voltage of a boost converter is given by the formula
Vo = Vin*n/(1 - D)
This circuit runs at a duty cycle of 65% and outputs 48V. A normal boost converter with an efficiency of 90% would output
Vo = 12*0.9/(1-0.65) = 30.85V
The output voltage of a two-inductor switched boost converter for the same duty cycle is
Vo = Vin*n*(1+D)/(1-D)
Substituting the appropriate values,
Vo = 12 *0.9*(1+0.65)/(1-0.65) = 50V
This circuit, in reality, outputs 48V.
An LTspice simulation of the same circuit achieved 92% efficiency.
