Datasheet

D
´
Vout2 + V Vssoffset
R1 =
Vref Iss
´
D -
Vref R1
R2 =
Vout2 + V Vref
V = Vout1 Vout2D -
> ´ - ´ DR1 2800 Vout1 180 V
SS/TR
TPS54620
EN
PWRGD
SS/TR
TPS54620
EN
PWRGD
VOUT1
VOUT 2
R1
R2
R3
R4
EN=2V/div
Vout1=1V/div
Vout2=1V/div
Time=20msec/div
TPS54620
SLVS949C – MAY 2009– REVISED MAY 2011 www.ti.com
To ensure proper operation of the device, the calculated R1 value from Equation 6 must be greater than the
value calculated in Equation 9.
(6)
(7)
(8)
(9)
Figure 26. Ratiometric and Simultaneous Startup Sequence
Figure 27. Ratio-metric Startup with Vout1 Leading Vout2
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