Functional Descriptions - Epson Power Supply IC S1F70000 Technical Manual

S1F76540 Series
Table 2.4 AC characteristics
Parameter
Internal clock frequency 1
Internal clock frequency 2

FUNCTIONAL DESCRIPTIONS

Clock Generator Circuit
As the S1F76540 has a built-in clock generator circuit,
no more parts are required for voltage boost control.
The clock frequency changes according to the FC pin
voltage level as defined on Table 2.5. Low Output mode
or High Output mode is selectable. This allows fre-
quency selection according to the used capacitance and
Table 2.5 FC pin setup
FC pin Mode
High (V ) Low Output
DD
Low (V ) High Output 16.0 kHz (Typ.) I
I
*1 See the DC characteristics table for current consumption.
*2 See Section Page 2-32 for the output ripple definition and calculation.
2–22
Symbol
FC = V ,
DD
P = V
OFF1
f
CL1
P = V
OFF2
Pin used: C1P
FC = V ,
I
P = V
OFF1
f
CL2
P = V
OFF2
Pin used: C1P
Clock frequency Current
consumption
4.0 kHz (Typ.)
OP
EPSON
Conditions
Ta = 25 C
I
DD
Ta = –30 C
to +85 C
Ta = 25 C
I
DD
Ta = –30 C
to +85 C
load current as the boost output impedance changes de-
pending on the clock frequency and external booster ca-
pacitance. However, the High Output mode has the
current consumption approximately four times larger
than the Low Output mode.
Characteristics
Output ripple
I (*1) V (*2)
OP RR
Approx. 4 V Approx. 1/4 See Figure A1. See Figure A1.
RI
V = 0 V and V = –5.0 V
DD I
unless otherwise noted
Min. Typ. Max. Unit
3.0 4.0 6.0
2.0 4.0 7.0
12.0 16.0 24.0
8.0 16.0 28.0
Output Capacitance
impedance
See Figure A1. See Figure A1.
S1F70000 Series
Technical Manual
kHz
kHz
kHz
kHz