8

LTC1044A

Battery Splitter

A common need in many systems is to obtain (+) and

(–) supplies from a single battery or single power supply

system. Where current requirements are small, the circuit

shown in Figure 9 is a simple solution. It provides sym-

metrical

± output voltages, both equal to one half 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 LTC1044A is shown in Figures

10 and 11.

Figure 10 shows two LTC1044As connected in parallel to

provide a lower effective output resistance. If, however,

the output resistance is dominated by 1/(f

× C1), increas-

ing the capacitor size (C1) or increasing the frequency will

be of more benefit than the paralleling circuit shown.

Figure 11 makes use of “stacking” two LTC1044As to

provide even higher voltages. A negative voltage doubler

or tripler can be achieved, depending upon how pin 8 of the

second LTC1044A is connected, as shown schematically

by the switch. The available output current will be dictated/

decreased by the product of the individual power conver-

sion efficiencies and the voltage step-up ratio.

1

2

3

4

8

7

6

5

LTC1044A

OUTPUT

COMMON

+

C1

10

µF

12V

C2

10

µF

LTC1044A • F09

+

Figure 9. Battery Splitter

1

2

3

4

8

7

6

5

LTC1044A

+

C1

10

µF

1

2

3

4

8

7

6

5

LTC1044A

1/4 CD4077

LTC1044A • F10

+

C1

10

µF

C2

20

µF

*

*THE EXCLUSIVE NOR GATE SYNCHRONIZES BOTH LTC1044As TO MINIMIZE RIPPLE

Figure 10. Paralleling for Lower Output Resistance

Figure 11. Stacking for Higher Voltage

1

2

3

4

8

7

6

5

LTC1044A

+

10

µF

10

µF

LTC1044A • F11

10

µF

1

2

3

4

8

7

6

5

LTC1044A

+

10

µF

+

+

S

APPLICATI

I FOR ATIO