www.ti.com

FEATURES OF THE PTH/PTV FAMILY OF NONISOLATED WIDE OUTPUT ADJUST POWER

Soft-Start Power Up

PTV08040W

6,7

13,14

20,21

4

5

11

15

Track

GND

GND

V (5V/div)

I

I (2 A/div)

I

t-Time=4ms/div

V

(1V/div)

O

PTV08040W

SLTS257A – SEPTEMBER 2005 – REVISED JANUARY 2007

MODULES

The Auto-Track feature allows the power-up of multiple PTH/PTV modules to be directly controlled from the

Track pin. However in a stand-alone configuration, or when the Auto-Track feature is not being used, the Track

Figure 11. Track Pin Connection

When the Track pin is connected to the input voltage the Auto-Track function is permanently disengaged. This

allows the module to power up entirely under the control of its internal soft-start circuitry. When power up is

under soft-start control, the output voltage rises to the set-point at a quicker and more linear rate.

From the moment a valid input voltage is applied, the soft-start control introduces a short time delay (typically

8 ms–15 ms) before allowing the output voltage to rise.

Figure 12. Power-Up Waveform

14

Submit Documentation Feedback