Datasheet

Load
Current
Output
Voltage
t
OC Limit
t
LIM
delay
3.3 V
18 V
HV_EN
HV_UVLO
HV_EN & HV_UVLO
S
3P3
S
HV
OUT
I
DIS
0V
EN
3.3 V
TPS22980
www.ti.com SLVSB61C –DECEMBER 2011–REVISED SEPTEMBER 2013
Figure 8 shows possible combinations of EN and HV_EN controlling OUT of the TPS22980.
Figure 8. Logic Waveforms Displaying the Transition Between VHV and V3P3
OVER-CURRENT LIMIT AND SHORT CIRCUIT PROTECTION
When the load at OUT attempts to draw more current than the limit set by the external RISET resistors for the
V3P3 switch and VHV switch (for both S0 and S3 modes), the device will operate in a constant current mode
while lowering the output voltage. Figure 9 shows the delay, t
LIM
, which occurs when an over-current fault is
detected until the output current is lowered to ILIMHV tolerances for VHV or ILIM3V3 tolerances for V3P3 as
shown in Figure 4.
Figure 9. Overcurrent Output Response
All short circuit conditions are treated as over-current conditions. In the event of a short circuit, the device will
limit the output current to the corresponding R
SET
value and continue to do so until thermal shutdown is
encountered or the short circuit condition is removed.
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