Datasheet

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UVLO
Threshold
V (5V/Div)
I
V (1V/Div)
O
HORIZTAL SCALE:5ms/Div
StartupPeriod
HORIZTAL SCALE:10ms/Div
V 1(1V/Div)
O
V (1V/Div)
O
2
I 2(5 A/Div)
O
ASIC
VC ORE
VC CI O
PTH12010L
1
10
4
5
62
3
9
Tra ck
GND
Inhibit
7
Vadj
Sense
+
C2
330 Fm
C4
330 Fm
C6
0.68 Fm
C5
0.1 Fm
C3
330 Fm
C1
330 Fm
R1
2kW
R5
10kW
R4
100kW
R3
11kW
R2
130 W
+
+
PTH12020W
7
10
4
5
62
3
9
Tra ck
V
I
V
I
V =12V
I
V 1=3.3V
O
V 2=1.8V
O
I 2
O
V
O
V
O
GNDInhibit
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
SLTS257B – SEPTEMBER 2005 – REVISED JANUARY 2008
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
disabled when not being used. This is accomplished by connecting the Track pin to the input voltage, V
I
. 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 Submit Documentation Feedback Copyright © 2005 – 2008, Texas Instruments Incorporated
Product Folder Link(s): PTV08040W