Epson Power Supply IC S1F70000 Technical Manual page 166

Output voltage adjustment
To ensure stable output, any circuit that adjusts the out-
put voltage must contain C1, R
switching current from affecting V
also satisfy the condition I
O
V
SW
V
I
S1F76310M
GND
Voltage adjustment
circuit
S1F70000 Series
Technical Manual
and R . To stop
A B
, the circuit must
O
< I .
R
Step-up
voltage
output
R
A
I
O
V
O
I
R
C
L
R
C B
(I < I )
O R
EPSON
The following figure summarizes the relevant circuits
inside an S1F76300 series chip.
V is connected to the level shift and buffer circuit,
O
which provide the gate bias for the switching transistor
driving the inductor. The current drain, I
the load and is typically 10 A. The current, I
through the internal resistors R1 and R2, is typically
1 A.
V
SW
Level
Controller
shifter
Buffer
S1F76300 Series
, varies with
O1
,
O2
V
I
I I
O1 O
V
O
I
O2
R1
Comparatpr
R2
V
REF
4–21