Datasheet
LTC1046
8
1046fb
U
SA
O
PP
L
IC
AT
ITY
P
I
CA
L
Battery Splitter
A common need in many systems is to obtain positive and
negative supplies from a single battery or single power
supply system. Where current requirements are small, the
circuit shown in Figure 10 is a simple solution. It provides
symmetrical positive or negative output voltages, both
Figure 10. Battery Splitter
1
2
3
4
8
7
6
5
V
+
OSC
LV
V
OUT
BOOST
CAP
+
GND
CAP
–
LTC1046
C1
10µF
V
B
9V
C2
10µF
OUTPUT COMM0N
REQUIRED FOR V
B
< 6V
3V ≤ V
B
≤ 12V
1046 F10
+V
B
/2
4.5V
–V
B
/2
–4.5V
+
+
equal to one half the input voltage. The output voltages are
both referenced to Pin 3 (output common). If the input
voltage between Pin 8 and Pin 5 is less than 6V, Pin 6
should also be connected to Pin 3, as shown by the
dashed line.
Paralleling for Lower Output Resistance
Additional flexibility of the LTC1046 is shown in Figures 11
and 12. Figure 11 shows two LTC1046s connected in
parallel to provide a lower effective output resistance. If,
however, the output resistance is dominated by 1/fC1,
increasing the capacitor size (C1) or increasing the fre-
quency will be of more benefit than the paralleling
circuit shown.
Figure 12 makes use of “stacking” two LTC1046s to
provide even higher voltages. In Figure 12, a negative
voltage doubler or tripler can be achieved depending upon
how Pin 8 of the second LTC1046 is connected, as shown
schematically by the switch.
1
2
3
4
8
7
6
5
V
+
OSC
LV
V
OUT
BOOST
CAP
+
GND
CAP
–
LTC1046
C1
10µF
C1
10µF
+
1
2
3
4
8
7
6
5
V
+
OSC
LV
V
OUT
BOOST
CAP
+
GND
CAP
–
LTC1046
1/4 CD4077
+
C2
20µF
1046 F11
V
OUT
= –(V
+
)
OPTIONAL SYNCHRONIZATION
CIRCUIT TO MINIMIZE RIPPLE
V
+
+
Figure 11. Paralleling for 100mA Load Current
1
2
3
4
8
7
6
5
V
+
OSC
LV
V
OUT
BOOST
CAP
+
GND
CAP
–
LTC1046
V
+
10µF
C1
10µF
–(V
+
)
+
1
2
3
4
8
7
6
5
V
+
OSC
LV
V
OUT
BOOST
CAP
+
GND
CAP
–
LTC1046
FOR V
OUT
= –2V
+
FOR V
OUT
= –3V
+
+
10µF10µF
1046 F12
V
OUT
++
Figure 12. Stacking for Higher Voltage