Datasheet

USB
DC_IN
BAT
LOUT
EN
VOUT
TPS22933A
USB Port
DC Input
GND
CAP
Battery
MSP430
Cm
Switched
Load
GND
Battery
USB
DC_IN
BAT
LOUT
EN
VOUT
CAP
USB Port
DC Input
TPS22933A
Power
Multiplexer
Output
Unused
www.ti.com Operation
3.5 Operation Examples
The TPS22933A allows for much flexibility in a variety of applications and the EVM can be used to
demonstrate its flexibility.
Application Examples:
3.5.1 Application Examples:
3.5.1.1 3-Input Multiplexer with Always On and Switched LDO
This example shows the most common use of the TPS22933A. Any handheld device might have three
input sources: Lithium battery, USB port and a DC jack. Once power is applied to any of the inputs, the
TPS22933A powers up the LDO and the MSP430 microcontroller is powered through the LOUT pin. At
this point, the MSP430 may decide to enable the VOUT to supply current to a subsystem – or, it may wait
until the specific functionality is required and power it then.
Figure 2. 3-Input MUX with LDO
3.5.1.2 3-Input Multiplexer with LDO Unused
This example shows the TPS22933A used solely as a 3-input multiplexer with the LDO left unused. The
CAP pin is used as the output of the multiplexer. Since the CAP is simply the highest of the three inputs,
the CAP pin will be as high as the input supply (minus the drop across the input switch). In this use in
particular the user needs to keep in mind that the voltage picker has a 150mV (typical) switchover point.
With a 2.4Ω R
ON
, the maximum current would be limited by not only the power dissipation, but also by the
switchover voltage. For 150mV and 2.4 Ω, a current of 62.5mA may result in a switch between supplies of
equal voltage.
Figure 3. 3-Input Power MUX
5
SLVU589–October 2011 Using the TPS22933AEVM-005 Triple-Input Power Multiplexer with Auto-Select
and Integrated LDO
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