Operation Principles Of Chopper; Type Switching Regulator - Epson LX-HOO Technical Manual

2.3.2.1 Operation Principles of Chopper Type Switching Regulator
The operating principle of the switching regulator is illustrated in Figures 2-6 and 2-7.
Fig. 2-6 Chopper Switching Regulator Circuit
When switching transistor St is on, current Is is supplied to inductor L in proportion to time;
When energy has accumulated in the inductor L, current 10 is supplied to the load. When St is off, the
energy accumulated in L causes
=
I D
The longer the on-time of St, the more the output voltage increases, and the shorter the on-time of St,
the more the output voltage decreases. Theoretically, electric power efficiency is assumed to be 100%;
Output voltage Vo = + Vi
Vo)
L
current
"
St
1
L
c
to
Fig. 2-7 Voltage Waveforms
to flow via diode D and to supply load current 10;
2-6
V/I
Vi -
1P
=
= L