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UVLO

Threshold

V (5V/Div)

I

V

(1V/Div)

O

HORIZTAL SCALE:5ms/Div

StartupPeriod

HORIZTAL SCALE:10ms/Div

V 1(1V/Div)

O

V

(1V/Div)

O2

I 2(5 A/Div)

O

ASIC

VC ORE

VC CI O

PTH12010L

1

10

4

5

6

2

3

9

Tra ck

GND

Inhibit

7

Vadj

Sense

+

C2

330 F

m

C4

330 F

m

C6

0.68 F

m

C5

0.1 F

m

C3

330 F

m

C1

330 F

m

R1

2kW

R5

10kW

R4

100kW

R3

11kW

R2

130 W

+

+

PTH12020W

7

10

4

5

6

2

3

9

Tra ck

V

I

V

I

V =12V

I

V 1=3.3V

O

V 2=1.8V

O

I 2

O

V

O

V

O

GND

Inhibit

1

Up

Adjust

+

TL7702B

V

CC

GND

SENSE

RESIN

REF

CT

RESET

RESET

8

7

2

1

3

5

6

4

+

Dn

Sense

8

8

PTV08040W

SLTS257A – SEPTEMBER 2005 – REVISED JANUARY 2007

Figure 18. PTH08040W Startup

Figure 19. Prebias Startup Waveforms

Note

1. The prebias start-up feature is not compatible with Auto-Track. If the rise in the output is limited by the

voltage applied to the Track control pin, the output sinks current during the period that the track control

voltage is below that of the back-feeding source. For this reason, it is recommended that Auto-Track be

This raises the Track pin voltage well above the set-point voltage prior to the module’s start up, thereby

defeating the Auto-Track feature.

Figure 20. Application Circuit Demonstrating Prebias Startup

20

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