Boost Regulator

The Boost regulator produces output voltage greater than the input voltage (but of the same polarity).  The Boost regulator is shown in figure below, along with the two modes during the switch on and off time. 

Figure 1: Boost Regulator

During Mode 1, the switch is on and the input current, which rises, flows through inductor and transistor. During Mode 2, switch is off, and the current flows through L, C, load and diode. The inductor current falls until the switch is turned on again. The energy stored in inductor is transferred to the load. Since a high current is maintained when switch is ON, this high current charges the capacitor to a higher voltage since capacitor voltage is integral of the current flowing through it. Thus a voltage higher than the input voltage can be achieved using a Boost Regulator.

The output voltage in this case is given as

Where, k is 

The circuit diagram of a Boost Regulator and its transient analysis are provided in the following pages:

Figure 2: Circuit Diagram of a Boost Regulator

Here, parameters of V2 are as following:

Parameter	Value
V1	0
V2	10
TD	0
TR	0.01u
TF	0.01u
PW	28.55u
PER	50u

Figure 3: Voltage Output of the circuit in figure 2

Figure 3 shows the output voltage of the boost converter. It can be seen that the output voltage has been increased. This is in accordance with eq. (i). It can be predicted that the output voltage will increase as the on time of the switch increases (as value of k increases in eq. i).

Figure 4: Current through inductor L1 of the circuit in figure 2

Figure 4 shows the current through L1 rising during the ON time of the switch and falling during the off time. It is this rising current that charges the capacitor to a higher voltage when the switch is turned off.