PTH12020W Datasheet, PDF (14/27 Pages) Texas Instruments – 18-A, 12-V INPUT NON-ISOLATED WIDE-OUTPUT ADJUST POWER MODULE

PTH12020W/L
SLTS208E – MAY 2003 – REVISED OCTOBER 2005
www.ti.com
For simple point-of-use applications, the PTH12050 (6 A) provides operating features such as an on/off inhibit,
output voltage trim, pre-bias start-up and over-current protection. The PTH12060 (10 A), and PTH12010 (12 A)
include an output voltage sense, and margin up/down controls. Then the higher output current, PTH12020 (18 A)
and PTH12030 (26 A) products incorporate overtemperature shutdown protection.
The PTV12010 and PTV12020 are similar parts offered in a vertical, single in-line pin (SIP) profile, at slightly
lower current ratings.
All of the products referenced in Table 5 include Auto- Track™. This feature was specifically designed to simplify
the task of sequencing the supply voltages in a power system. This and other features are described in the
following sections.
Soft-Start Power UP
The Auto-Track feature allows the power-up of multiple PTH 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 pin should
be directly connected to the input voltage, V_in (see Figure 12).
12 V
10 9 8
5
Up Dn Track Sense
2
V_IN PTH12020W
6
V_O
Inhibit GND Adjust
3 174
CIN
1,000 mF
R _SE,T2 kW
0.1 W, 1 %
3.3 V
COUT
330 mF
GND
GND
Figure 12. Power-Up Application Circuit
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.
Vin (5 V/Div)
Vo (1 V/Div)
Iin (5 A/Div)
HORIZ SCALE 5 ms/Div
Figure 13. Power-Up Waveforms
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. The output then progressively rises to the
module’s setpoint voltage. Figure 13 shows the soft-start power-up characteristic of the 18-A output product
(PTH12020W), operating from a 12-V input bus and configured for a 3.3-V output. The waveforms were
measured with a 5-A resistive load and the Auto-Track feature disabled. The initial rise in input current when the
input voltage first starts to rise is the charge current drawn by the input capacitors. Power-up is complete within
25 ms.
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