The boost converter is sometimes referred to as a Step Up Switchmode supply. Its basic application is to convert a low value, unregulated input voltage to a higher output voltage. For the model values used in this example, output voltage is determined by the relationship
Vo = V in/ (1-D)
where D is the switching duty cycle in the converter circuit.
The duty cycle (D) is determined by the value of the control voltage (V2) and is proportional to V2 so the smaller the V2, the smaller the duty cycle and the lower the output voltage.
In the example shown in the attach file, the boost converter is stepping up a 5V input to 10V into a 50 ohm load when the control voltage is 0.5V (a duty cycle of 0.5 (50.%)). Adjusting the control voltage between 0.1V and 0.9V produces an output voltage between 5.5 and 48V.