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Date: 1/11/05

SP34063A 1.5A Buck/Boost/Inverting DC-DC Switching Regulator

© Copyright 2005 Sipex Corporation

TYPICAL INVERTING CONVERTER CIRCUIT

This is a typical boost converter configuration. The working process in the steady state is similar to a boost converter,

the difference in this situation is that the voltage at the non-inverting pin of the comparator is equal to 1.25V +V

OUT,

then Vpin5 = V

OUT

*R2/(R1+R2) = 1.25V, + V

OUT.

The output voltage can be decided by V

OUT

= -1.25V*(R1+R2)/R1

(V).

S

Q

R

B

A

Ipk

OSC

CT

+

-

1.25V

Reference

Regulator

5

7

8

4

1

2

3

L2 1.0 µH

VOUT

Optional

Filter

C3

100 µF

C2

1000 µF

VOUT

-12V/100mA

R1 953k

R2 8.2k

C1

100µF

RSC

0.24

D1

1N5819

L1

88 µH

+

+

+

6

CT

1500 pF

SP34063A