1 Features
1• Powered from 3.3 V
• 4.5-V to 19.8-V High-Voltage Switch
• 3-V to 3.6-V Switch
• Adjustable Current Limit
• Thermal Shutdown
• Make Before Break Switch
• High-Voltage Discharge Before Low-Voltage Make
• Reverse Current Blocking

2 Applications
• Notebook Computers
• Desktop Computers
• Power Management Systems

3 Description
The TPS22981 device is a current-limited power mux
providing a connection to a peripheral device from either a low-voltage supply (3 V to 3.6 V) or a high-
voltage supply (4.5 V to 19.8 V). The desired output
is selected by digital control signals.
The high-voltage (VHV) and low-voltage (V3P3)
switch current limits are set with external resistance.
Once the current limit is reached, the TPS22981 will control the switch to maintain the current at this limit.
When the high-voltage supply is not present, the
TPS22981 will maintain the connection to the output from the low-voltage supply. Upon the presence of a
high-voltage line and high-voltage enable signal, the
high-voltage switch is turned on in conjunction with
the low-voltage switch until a reverse current is detected through the low-voltage switch, allowing a
seamless transition from low voltage to the high- voltage supply with minimal droop and shoot-through
current.
To prevent current backflow during a switch over from
a VHV connection to a V3P3 connection, the
TPS22981 will break the VHV connection, discharge
the output to approximately 3.3 V and then make the
V3P3 connection. The output may transition to 0 V
when a load is present, before returning to 3.3 V.
The TPS22981 is available in a 4 mm × 4 mm × 1
mm VQFN package.