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V =12V

I

V 1=3.3V

O

V 2=1.8V

O

2.49kW

16.9kW

50 W

10kW

2.2 F

m

0.1 F

m

C 1

O

C 2

O

C 1

I

C 2

I

+

U3

TL7712A

GND

SENSE

RESIN

REF

CT

RESET

RESET

8

7

2

1

3

5

6

4

U1

U2

+

UVLOProg

Inhibit/

GND

Track

PTV08040W

PTV08040W

UVLOProg

Inhibit/

+Sense

+Sense

-Sense

-Sense

GND

Track

N/C

N/C

PTV08040W

SLTS257A – SEPTEMBER 2005 – REVISED JANUARY 2007

Notes on Use of Auto-Track™

1. The Track pin voltage must be allowed to rise above the module set-point voltage before the module

regulates at its adjusted set-point voltage.

2. The Auto-Track function tracks almost any voltage ramp during power up, and is compatible with ramp

speeds of up to 1 V/ms.

4. The module cannot follow a voltage at its track control input until it has completed its soft-start

initialization. This takes about 20 ms from the time that a valid voltage has been applied to its input.

During this period, it is recommended that the Track pin be held at ground potential.

Auto-Track is disabled, the output voltage rises at a quicker and more linear rate after input power has

been applied.

Figure 15. Sequenced Power Up and Power Down Using Auto-Track

18

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