Datasheet

SS/TR
TPS54240
EN
PWRGD
SS/ TR
EN
PWRGD
VOUT 1
VOUT 2
R 1
R 2
R3
R 4
TPS54240
EN
TPS54160
3
SS/TR
4
PWRGD6
EN
TPS54160
3
SS/TR
4
PWRGD6
TPS54240
TPS54240
EN1,EN2
VOUT1
VOUT2
TPS54240
www.ti.com SLVSAA6A –APRIL 2010–REVISED DECEMBER 2012
DETAILED DESCRIPTION (continued)
Figure 32. Schematic for Ratiometric Start-Up Figure 33. Ratio-Metric Startup using Coupled
Sequence SS/TR pins
Figure 32 shows a method for ratio-metric start up sequence by connecting the SS/TR pins together. The
regulator outputs will ramp up and reach regulation at the same time. When calculating the slow start time the
pull up current source must be doubled in Equation 6. Figure 33 shows the results of Figure 32.
Figure 34. Schematic for Ratiometric and Simultaneous Start-Up Sequence
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