TPS54361_16 Datasheet, PDF (17/51 Pages) Texas Instruments – 4.5-V to 60-V Input, 3.5-A, Step-Down DC-DC Converter

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Feature Description (continued)
TPS54361
SLVSC39C – NOVEMBER 2013 – REVISED FEBRUARY 2016
Figure 28. Operation of SS/TR Pin When Starting
7.3.9 Sequencing
Many of the common power supply sequencing methods can be implemented using the SS/TR, EN and PWRGD
pins. The sequential method can be implemented using an open drain output of a power on reset pin of another
device. The sequential method is illustrated in Figure 29 using two TPS54361 devices. The power good is
connected to the EN pin on the TPS54361 which enables the second power supply once the primary supply
reaches regulation. If needed, a 1-nF ceramic capacitor on the EN pin of the second power supply provides a 1-
ms start-up delay. Figure 31 shows the results of Figure 29.
TPS54361
TPS54361
TPS5413610
PWRGD
EN
EN
3 EN
SS /TR
SS /TR
PWRGD
4 SS/TR
6 PWRGD
Figure 29. Schematic for Sequential Start-Up
Sequence
TTPPSS554413601
3 EN
4 SS/TR
6 PWRGD
Figure 30. Schematic for Ratiometric Start-Up
Sequence
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