Epson S1F70000 Power Supply User Manual


 
S1F76540 Series
2–22 EPSON S1F70000 Series
Technical Manual
Table 2.4 AC characteristics
V
DD = 0 V and VI = –5.0 V
unless otherwise noted
Parameter Symbol Conditions Min. Typ. Max. Unit
FC = VDD,
Ta = 25°C 3.0 4.0 6.0 kHz
Internal clock frequency 1 f
CL1
POFF1 = VI
P
OFF2
= V
DD
Ta = –30°C
2.0 4.0 7.0 kHz
Pin used: C1P to +85°C
FC = VI,
Ta = 25°C 12.0 16.0 24.0 kHz
Internal clock frequency 2 f
CL2
POFF1 = VI
P
OFF2
= V
DD
Ta = –30°C
8.0 16.0 28.0 kHz
Pin used: C1P to +85°C
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
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.
Table 2.5 FC pin setup
Characteristics
FC pin Mode
Clock frequency Current Output ripple
Output Capacitance
consumption
impedance
High (VDD) Low Output 4.0 kHz (Typ.) IOP (*1) VRR (*2)
See Figure A1. See Figure A1.
Low (VI) High Output 16.0 kHz (Typ.)
IOP × Approx. 4
VRI × Approx. 1/4
See Figure A1. See Figure A1.
*1 See the DC characteristics table for current consumption.
*2 See Section Page 2-32 for the output ripple definition and calculation.