Raytheon Pathfinder 1200 Instruction Manual page 91

Its peak value is equal to the supply voltage E 1.
Ed
=
E1
> - - - - -
Toff - - - _
Output Voltage
=
E2
FIG. 6-10 ACROSS VOLTAGE OF THE DIODE
Therefore, the output voltage E2 is given by the average of the supply voltage.
Consequently, the output voltage is described by the following equation:
Ton
E2
= -
El
Ton + Toff
Therefore, the output is held at a constant voltage by varying the switching time
ratio according to the supply voltage.
6-25