Datasheet

V
IN
GND
OC
V
OUT
Off
On
ON
5.5-V
Battery
10 µF
100 kW
0.1 µF
500 W
TPS22941, TPS22942, TPS22943, TPS22944, TPS22945
www.ti.com
SLVS832C NOVEMBER 2008REVISED NOVEMBER 2009
APPLICATION INFORMATION
Figure 26. Typical Application Circuit, Active-High Enabled Device
(TPS22943, TPS22944 and TPS22945 Only)
On/Off Control
The ON pin controls the state of the switch. Activating ON continuously holds the switch in the on state as long
as there is no fault. An undervoltage on V
IN
or a junction temperature in excess of 150°C overrides the ON
control to turn off the switch. ON is active high and has a low threshold, making it capable of interfacing with
low-voltage signals.
Undervoltage Lockout
The undervoltage lockout turns off the switch if the input voltage (V
IN
) drops below the undervoltage lockout
threshold. With the ON pin active, the input voltage rising above the undervoltage lockout threshold causes a
controlled turn-on of the switch, which limits current overshoots.
Thermal Shutdown
Thermal shutdown protects the part from internally or externally generated excessive temperatures. During an
overtemperature condition the switch is turned off. The switch automatically turns on again if the temperature of
the die drops below the threshold temperature.
Reverse Voltage
If the voltage at the V
OUT
pin is larger than the V
IN
pin, large currents may flow and can cause permanent
damage to the device. TPS2294x is designed to control current flow only from V
IN
to V
OUT
.
Fault Reporting
When an overcurrent, input undervoltage, or overtemperature condition is detected, OC is set active low to signal
the fault mode. OC is an open-drain MOSFET and requires a pullup resistor between V
IN
and OC. During
shutdown, the pulldown on OC is disabled, reducing current draw from the supply.
Current Limiting
When the switch current reaches the maximum limit, the TPS22921/2/3/4/5 operates in a constant-current mode
to prohibit excessive currents from causing damage. TPS22921/3 has a current limit of 40 mA and TPS22922/4/5
has a current limit of 100 mA. A current limit condition immediately pulls the fault signal pin low (OC pin), and the
part remains in the constant-current mode until the switch current falls below the current limit.
Input Capacitor
To limit the voltage drop on the input supply caused by transient in-rush currents when the switch turns-on into a
discharged load capacitor or a short-circuit, a capacitor needs to be placed between V
IN
and GND. A 1-μF
ceramic capacitor, C
IN
, placed close to the pins is usually sufficient. Higher values of CIN can be used to further
reduce the voltage drop.
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Product Folder Link(s): TPS22941 TPS22942 TPS22943 TPS22944 TPS22945