Notes on Use of Auto-Track™

C

O1

V

O1

2.5 V

UDG-08150

+Sense

V

O

-Sense

V

O

R

SET1

GND

PTH08T210W

V

I

V

I

AutoTrack

TurboTrans

C

I1

+

R

TT1

C

I2

GND

+

+

RESET

GND

5

6

4

SENSE

7

RESIN

2

REF

1

8

V

CC

CT

3

RESET

U3

TL7712A

C

REF

0.1 mF

C

T

2.2 mF

R

RESET

10 kW

C

O2

V

O2

5.0 V

+Sense

V

O

-Sense

V

O

U2

PTH08T255W

V

I

V

I

V

I

V

I

AutoTrack

TurboTrans

R

TT2

GND

+

V

I

12 V

V

O

Adj

GND GND GND

AGND

R

SET2

GND GND GND GND

V

O

Adj

(1)

100 kW

PTH08T255W

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.

disabled, the output voltage rises according to its softstart rate after input power has been applied.

6. The Auto-Track pin should never be used to regulate the module's output voltage for long-term, steady-state

operation.

(1)

When using Auto-Track with the PTH08T255W, a 100-k

AutoTrack pins.

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

Copyright © 2008, Texas Instruments Incorporated

21

Product Folder Link(s): PTH08T255W