S1F76540MOC Epson Electronics America, Inc., S1F76540MOC Datasheet - Page 11

• Manufacturer Part Number: S1F76540MOC
• Description: Charge Pump Type Dc/dc Converter
• Manufacturer: Epson Electronics America, Inc.

5. FUNCTIONAL DESCRIPTION
Section 5.3. (Case where the split ratio of resistance values for setting does not depend on the temperature)
When setting the temperature coefficient other than that specifiable in S1F76540 to the stabilizing potential,
change it using a thermistor resistor, etc. shown in Fig. 9.15.
temperature coefficient of the internal reference voltage.
8
Therefore R1 and R2 will be determined as follows.
[Changing the temperature coefficient]
The temperature coefficient of the stabilizing potential depends on that of the reference voltage described in
The following shows how to obtain the V
If the temperature coefficient of R1 is equal to that of R2 in expression (5.3), V
[Notes on using the voltage stabilization circuit]
[Measures against oscillation]
Installing external parts enables you to take measures of oscillation.
The following shows the parts used and recommended values.
• To keep the S1F76540 absolute maximum rating, the setting resistor must be connected between V
• The stabilizing potential adjusting pin “RV” has the too high input impedance, which may result in the
• When using the stabilizing power supply voltage pin “VRI”, short-circuit the VRI and VO pins with a
• Capacity between V
• Serial equivalent resistance of output capacitor CO
R1 = 75kΩ
R2 = 825kΩ
T0
CTR1
CTR2
CT
R1(T0)
R2(T0)
V
V
regulator when connecting the S1F76540 in series will result in deterioration or destruction in this IC.
regulator being destabilized due to noises. When using this pin, shield the wiring section between the split
resistor and RV pin, or shorten the wiring as much as possible (see Fig.5.3).
shorter cable (see Fig.5.3), exceeding at high-magnification boosting using an external diode shown in
Section 9.8.
(Note 1) Specify the minimum necessary value because the ripple value of the output voltage increases.
V
REF
REG
REG
(T0)
of an S1F76540 that uses the regulator. Connecting R1 to V
(T) = {1+
(See item 9.4.)
:
:
:
:
:
:
:
25°C
Temperature coefficient of resistance R1 (Ratio between split resistance values at 25°C)
Temperature coefficient of resistance R2 (Ratio between split resistance values at 25°C)
Temperature coefficient (%/°C) of internal reference voltage
25°R1 value (Ω) at 25°C
25°R2 value (Ω) at 25°C
25°Internal reference voltage value (V) at 25°C
CTR2×R2(T0)
CTR1×R1(T0)
REG
and RV
×{1+(T－T0) ×
REG
:
value at temperature T.
220pF
EPSON
CT
100
:
} × V
S1F76540M0C Series Technical Manual (Rev.1.0)
REF
10Ω or more (Note 1)
(T0)
DD
of an S1F76540 that does not use the
･････Expression (5.3)
REG
depends only on the
DD
and