TPS65090 Datasheet, PDF (59/69 Pages) Texas Instruments – Front-End PMU With Switched-Mode Charger for 2 to 3 Cells In Series

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TPS65090
SLVSBO6B – JANUARY 2013 – REVISED JULY 2015
9 Power Supply Recommendations
The TPS65090A device integrates a power path management system that automatically switches power to the
load from either an AC adapter or from battery power. The voltage range for the AC adapter should fall within the
6 V to 17 V range. Battery power can be provided by either a dual or triple Li-Ion or Li-Polymer cell battery pack.
On power up, the battery pack is connected to the load by default. However, if a valid voltage is detected on the
VACS pin and the voltage on the VAC pin is higher than the battery voltage, the battery is disconnected and the
AC adapter is connected to the load through the external power path switches.
10 Layout
10.1 Layout Guidelines
For all switching power supplies, the layout is an important step in the design, especially at high peak currents
and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as
well as EMI problems. Therefore, use wide and short traces for the main current path and for the power ground
tracks. The input capacitor, output capacitor, and the inductor should be placed as close as possible to the IC.
Use a common ground node for power ground and a different one for control ground to minimize the effects of
ground noise. Connect these ground nodes at any place close to one of the ground pins of the IC.
The feedback divider should be placed as close as possible to the control ground pin of the IC. To lay out the
control ground, TI recommends short traces, as well as separation from the power ground traces. This avoids
ground shift problems, which can occur due to superimposition of power ground current and control ground
current.
A complete layout example can be found in the TPS65090EVM User's Guide (SLVU778).
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