DC/DC Converter
PF754-03
SCI7654M
0A
/C
0A
DESCRIPTION
The SCI7654 is a highly efficient, but low power-consumption DC-to-DC converter based on the advanced CMOS
technologies. It can generate an output voltage double/triple/quadruple times higher than the input (in negative
direction) if 4/3/2 external capacitors are attached.
With a built-in voltage regulator, the SCI7654 can provide a stable output by setting the DC/DC output to any voltage
via two external resistors. This is optimum to the LCD panel power supply as the stable output can have the negative
temperature gradient required for an LCD panel.
FEATURES
An input voltage can be boosted double/triple/quadruple to negative potential.
Input voltages: 2.4 to 5.5V (quadruple boosting), 2.4 to 7.3V (triple boosting), 2.4 to 11.0V (double
boosting)
Excellent vol tage conversion efficiency: 95% (Typ.)
Large output current: 20 mA (Max.) during quadruple boosting
Built-in voltage regulator (for stable voltage output)
Built-in reference voltage source for accurate regulation: 1.5
0.05V (CT0)
Regulator output voltage temperature gradient function: 0.04, 0.15, 0.35, 0.55%/C
Low current consumption: 130
A (Typ.)
Low standby current: 5.0
A (Max.)
Built-in oscillator circuit
5/6-time voltage boosting in negative potential by serial connection
Package: SCI7654M
0A
SSOP2-16pin (plastic), SCI7654C
0A
DIP-16pin (plastic)
BLOCK DIAGRAM
Double/Triple/Quadruple Boosting
95% Excellent Power Conversion Efficiency
Built-in Voltage Regulator
V
DD
POFF1
POFF2
FC
V
IN
C1P
C2P
C1N
C3N
C2N
TC1
TC2
RV
V
REG
V
RI
V
OUT
Power-Off
Control
Clock
Generator
Voltage Converter
Booster Control
Ref. Voltage
Circuit
Voltage Regulator
SCI7654M
0A
/C
0A
2
PIN CONFIGURATION
PIN DESCRIPTION
1
8
2
3
4
5
6
7
16
9
15
14
13
12
11
10
C2P
C2N
C3N
C1N
C1P
V
IN
POFF1
POFF2
V
OUT
V
RI
V
REG
RV
V
DD
FC
TC1
TC2
SSOP2-16pin/DIP-16pin
Pin No.
Pin Name
Function
1
V
OUT
Voltage output
2
V
RI
Regulator input
3
V
REG
Regulator output
4
RV
Input for regulator output voltage adjustment
5
V
DD
Input voltage pin (Positive)
6
FC
Internal clock rate switch input, and clock input in serial/parallel
connection (Common input pin)
7
TC1
Input for regulator output temperature gradient setup (1)
8
TC2
Input for regulator output temperature gradient setup (2)
9
POFF2
Power-off control input (2)
10
POFF1
Power-off control input (1)
11
V
IN
Input voltage pin (Negative)
12
C1P
Common double and quadruple boosting capacitor positive pin
13
C1N
Double boosting capacitor negative pin
14
C3N
Quadruple boosting capacitor negative pin
15
C2N
Triple boosting capacitor negative pin
16
C2P
Triple boosting capacitor positive pin
3
SCI7654M
0A
/C
0A
ELECTRICAL CHARACTERISTICS
(Unless otherwise designated: Ta=30
V to +85
C, V
DD
=0V, V
IN
=5.0V)
Rating
Symbol
Min.
Max.
Unit
Remark
Input Power Voltage
V
IN
-26.0/N
V
DD
+0.3
V
N=Boosting time;
at V
IN
pin
Input Pin Voltage
V
I
V
IN
-0.3
V
DD
+0.3
V
POFF1, POFF2
TC1, TC2, FC pins
Output Pin Voltage 1
V
0C1
V
IN
-0.3
V
DD
+0.3
V
At C1P and C2P pins
Output Pin Voltage 2
V
OC2
2 V
IN
-0.3
V
IN
+0.3
V
At C1N pin
Output Pin Voltage 3
V
OC3
3 V
IN
-0.3
2 V
IN
+0.3
V
At C2N pin
Output Pin Voltage 4
V
OC4
4 V
IN
-0.3
3 V
IN
+0.3
V
At C3N pin
Regulator Input Power Voltage
V
RI
N V
IN
-0.3
V
DD
+0.3
V
N=Boosting time; at V
RI
pin
Regulator Input Pin Voltage
V
RV
N V
IN
-0.3
V
DD
+0.3
V
N=Boosting time; at RV pin
Output Voltage
V
0
N V
IN
-0.3
V
DD
+0.3
V
N=Boosting time; at V
OUT
and V
REG
pins
Input Current
I
IN
--
80
mA
At V
IN
pin
Output Current
I
OUT
--
N
4:
20
mA
N=Boosting time; at V
OUT
N>4: 80/N
and V
REG
pins
Allowable Loss
P
d
--
210
mW
--
Operating Temperature
T
opr
-30
85
C
--
Storage Temperature
T
stg
-55
150
C
--
Soldering Temperature and Time
T
sol
--
26010
C.S
Temperature at leads
ABSOLUTE MAXIMUM RATINGS
Characteristic
Symbol
Condition
Min.
Typ.
Max.
Unit
Input Power Voltage 1
V
IN1
During quadruple boosting
-5.5
--
-2.4
V
Input Power Voltage 2
V
IN2
During triple boosting
-7.3
--
-2.4
V
Input Power Voltage 3
V
IN3
During double boosting
-11
-2.4
V
Input Power Voltage N
V
INN
During large-time boosting using
-22/N
--
-2.4
V
external diodes
Boost Startup Input Power Voltage
V
STA
N=Boosting time, I
OUT
<200 A,
-22/N
--
-2.4
V
FC=VDD
Booster Output Voltage
V
OUT
--
-22
--
--
V
Regulator Input Voltage
V
RI
--
-22
--
-2.4
V
Regulator Output Voltage
V
REG
I
REG
=0, V
RI
=-22V,
--
--
-2.4
V
R
RV
=1M
Booster Output Impedance
R
OUT
I
OUT=10mA,
during quadruple
--
200
300
boosting
Booster Power Conversion
P
eff
I
OUT
=2 mA; during quadruple
--
95
--
%
Efficiency
boosting;
C1, C2, C3, C
OUT
=10 F Tantalum
Booster Operating Current
I
OPR1
FC=V
DD
, POFF1=V
IN
, POFF2=V
DD
;
--
130
220
A
Consumption 1
during no loading;
C1, C2, C3, C
OUT
=10 F Tantalum
Booster Operating Current
I
OPR2
FC=V
IN
, POFF1=V
IN
, POFF2=V
DD
;
--
520
880
A
Consumption 2
during no loading;
C1, C2, C3, C
OUT
=10 F Tantalum
Regulator Operating Current
I
OPVR
V
RI
=-20 V, during no loading,
--
10
15
A
Consumption
R
RV
=1 M
SCI7654M
0A
/C
0A
4
Characteristic
Symbol
Condition
Min.
Typ.
Max.
Unit
Static Current
I
Q
POFF1=V
IN
, POFF2=V
IN
, FC=V
DD
--
--
5.0
A
Input Leakage Current
I
LIN
At POFF1, POFF2, FC, TC1, TC2 pins
--
--
0.5
A
Stable Output Saturation
R
SAT
0<I
REG
<20mA
--
10
20
Resistance
(*1)
RV=V
DD
Ta=25C
Stable Output Voltage Stability
DV
R
-20V<V
RI
<-10V, I
REG
=1mA
--
0.2
--
%/V
(*2)
V
REG
=-15V
Ta=25C
Stable Output Load Variation
DV
0
V
RI
=-20V V
REG
=-15V
--
30
50
mV
(*3)
Ta=25C
0<I
REG
<20mA
Reference Voltage
V
REF0
TC1 = V
DD
, TC2 = V
DD
-1.55
-1.50
-1.45
V
(Ta = 25
C)
V
REF1
TC1 = V
DD
, TC2 = V
IN
-1.70
-1.50
-1.30
V
V
REF2
TC1 = V
IN
, TC2 = V
DD
-1.90
-1.50
-1.10
V
V
REF3
TC1 = V
IN
, TC2 = V
IN
-2.15
-1.50
-0.85
V
Reference Voltage Temperature
CT
0
TC1 = V
DD
, TC2 = V
DD
, SSO package
-0.07
-0.04
0
%/C
Coefficient
(*4)
CT
1
TC1 = V
DD
, TC2 = V
IN
, SSO package
-0.25
-0.15
-0.07
%/C
(*5)
CT
2
TC1 = V
IN
, TC2 = V
DD
, SSO package
-0.45
-0.35
-0.20
%/C
CT
3
TC1 = V
IN
, TC2 = V
IN
, SSO package
-0.75
-0.55
-0.30
%/C
V
IH
V
IN
=-2.0V to -5.5V
At POFF1, POFF2, FC, TC1,
0.2V
IN
--
--
V
Input Voltage Level
TC2 pins
V
IL
V
IN
=-2.0V to -5.5V
At POFF1, POFF2, FC, TC1,
--
--
0.8V
IN
V
TC2 pins
Capacitance of Booster Capacitors
C
MAX
Capacitors
--
--
47
F
C
1
, C
2
, C
3
(*1) R
SAT
=
(V
REG
V
OUT
)
I
REG
(*2) V
R
=
V
REG
V
OUT
V
REG
(*3) R
0
=
V
REG
I
REG
(*4)
CT
=
|V
REF
(50C)| |V
REF
(0C)|
100
50C 0C
|V
REF
(25C)|
(*5) The reference voltage temperature coefficient of each chip product may vary depending on the used molding
materials. Perform the temperature test before use.
ELECTRICAL CHARACTERISTICS (continued)
5
SCI7654M
0A
/C
0A
FUNCTIONAL DESCRIPTION
Clock Generator Circuit
As the SCI7654 has a built-in clock generator circuit, it requires no external source at all. The clock rate changes
depending on the FC pin signal level, and the Low Output or High Output mode can be selected. This allows
a frequency selection according to the current capacitance and load current when the booster output impedance
changes depending on the clock rate and external booster capacitance.
Voltage Converter Circuit
The voltage converter receives a clock from the clock generator, and boosts the V
IN
input power voltage
quadruple, triple or double. Four converter circuits are required for quadruple boosting, three converts are
required for triple boosting, and dual converters are required for double boosting.
Voltage step-up diagram (during -5V input)
Reference Voltage Circuit
The SCI7654 has a built-in reference voltage circuit for the voltage regulator. The temperature coefficient of
reference voltage can be changed using pins TC1 and TC2, and a voltage having one of four types of temperature
gradients can be output at V
REG
pin for LCD driving.
V
DD
(0V)
V
IN
(-5V)
-10V
-15V
-20V
10V
15V
20V
double boosting
triple boosting
quadruple boosting
TC1
TC2
Reference Voltage, V
REF
(V)
Temperature Coefficient, CT (%/C)
Mode
Min.
Typ.
Max.
Min.
Typ.
Max.
CT0
H(V
DD
)
H(V
DD
)
-1.55
-1.5
-1.45
-0.07
-0.04
0
CT1
H
L(V
IN
)
-1.70
-1.5
-1.30
-0.25
-0.15
-0.07
CT2
L(V
IN
)
H
-1.90
-1.5
-1.10
-0.45
-0.35
-0.20
CT3
L
L
-2.15
-1.5
-0.85
-0.75
-0.55
-0.30
FC pin
Mode
Clock Rate
Current Consumption
Output Ripple
H (V
DD
)
Low Output
4.0 kHz (Typ.)
I
OP
V
RP
L (V
IN
)
High Output
16.0 kHz (Typ.)
Approx. 4 times of I
OP
Approx. 1/4 time of V
RI
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