Raytheon Pathfinder 1200 Instruction Manual page 92

(B) For Step Up Operation
While the transistor switch is ON, energy is sufficiently charged into the inductor.
During the OFF time, the charged energy in the inductor is added on the supply
voltage, and is fed to the load and capacitor CI via diode COSO 1.
While the switch is ON, the capacitor continuously feeds the power to the load;
therefore, the output is held to the constant voltage. Voltage across transistor
switch ESW is shown in Figure 6-11. Its peak value is equal to the output voltage
E2.
",
Therefore, the supply voltage is given by the time average of the output voltage,
Esw
=
E2
Supply Voltage = E1
----~-
.....
-
Toff - - _ Ton _ _
-I
FIG. 6-11 ACROSS VOLTAGE OF THE TRANSISTOR SWITCH
Consequently, the output voltage is described in the following equation:
E2
=
Ton
+
Toff
Toff
- El
6-26
The constant output voltage is obtained by the same manner as for step down
operation.