SLVA339A Datasheet, PDF (5/9 Pages) Texas Instruments – High-Vin, High-Efficiency Power Solution Using DC/DC Converter With DVFS

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Features
Proper sequencing is ensured in the design with the use of a NPN transistor and a P-channel MOSFET.
As required, Core 1.2 V at 600 mA comes first, and is followed by Static 1.2 V + VRTC at 251 mA. Then
comes Static 1.8 V at 230 mA, which in turn pulls down the gate of a P-channel MOSFET with the use of
a NPN transistor. Last, Static 3.3 V at 115 mA comes up.
(1) Use three such LDOs to power up DVDDA, DVDDB, and DVDDC. (It can be either 1.8 V or 3.3 V.)
(2) Rx = 0.499 MΩ, Ry = 1 MΩ for Vout = 1.8 V
(3) Rx = 1.8 MΩ, Ry = 1 MΩ for Vout = 3.3 V
(4) For proper sequencing of output, the enable of the LDOs are fed either from a 1.2-V output from TPS62232 if
DVDDX is 1.8 V or from a 1.8-V output from TPS62231 if DVDDX is 3.3 V.
Figure 2. Optional Circuit for DVDD_A, DVDD_B, and DVDD_C
SLVA339A – June 2009 – Revised May 2010
High-Vin, High-Efficiency Power Solution Using DC/DC Converters With DVFS
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