Datasheet

Output Voltage Holdup
2-4
2.4.2 Mode 2 Automatic Switching (TPS2110/1/2/3A Only)
In Mode 2 automatic switching, OUT connects to IN1 if the voltage at IN1 is
sufficiently high; otherwise, OUT connects to the higher of IN1 and IN2. The
threshold at which IN1 is selected corresponds to approximately 0.8 V at test
point TP3. The corresponding value of the IN1 voltage depends upon the
setting of potentiometer R2. Adjusting R2 clockwise increases the IN1
selection threshold voltage.
Refer to Table 2−2 to configure the EVM for Mode 2 automatic switching.
Table 2−2.EVM Shorting Jumper Placement for Mode 2 Automatic Switching
EVM
Device
Header
EVM
Device
J1 J2 J3 J4
HPA061−001 TPS2110A X X
HPA061−002 TPS2111A X X
HPA061−003 TPS2112A X X
HPA061−004 TPS2113A X X
A manufacturer can provide a secondary battery pack option to extend the
product run time with Mode 2 automatic switching. The TPS2110A–TPS2113A
drains the primary battery at IN1 and automatically switches to the secondary
battery at IN2.
2.5 Output Voltage Holdup
Headers J5–J8 select the output holdup capacitance.
The output voltage drops out for 60 µs (max) whenever the TPS211xA
switches between the IN1 and IN2 supplies. Some capacitance at the
TPS211xA output is necessary to prevent the output voltage from dropping too
much during the supply switchover. Excessive voltage drop can cause a
system to reset or lose data.
2.6 Switch Status (TPS2112/3/4/5A Only)
The switch status output can be monitored at the positive terminal of header
J1. A switch status output equal to logic 1 corresponds to an IN2 switch that
is on.