Datasheet
Overvoltage and Undervoltage Protection for VDDQ
V5IN (PWP), V5FILT (RGE) Undervoltage Lockout (UVLO) Protection
V5IN (PWP), V5FILT (RGE) Input Capacitor
Thermal Shutdown
TPS51116
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................................................................................................................................................................ SLUS609H – MAY 2004 – REVISED JULY 2009
TPS51116 monitors a resistor divided feedback voltage to detect overvoltage and undervoltage. If VDDQSET is
connected to V5IN or GND, the feedback voltage is made by an internal resistor divider inside VDDQSNS pin. If
an external resistor divider is connected to VDDQSET pin, the feedback voltage is VDDQSET voltage itself.
When the feedback voltage becomes higher than 115% of the target voltage, the OVP comparator output goes
high and the circuit latches as the top MOSFET driver OFF and the bottom MOSFET driver ON.
Also, TPS51116 monitors VDDQSNS voltage directly and if it becomes greater than 4 V TPS51116 turns off the
top MOSFET driver. When the feedback voltage becomes lower than 70% of the target voltage, the UVP
comparator output goes high and an internal UVP delay counter begins counting. After 32 cycles, TPS51116
latches OFF both top and bottom MOSFETs. This function is enabled after 1007 cycles of SMPS operation to
ensure startup.
TPS51116 has 5-V supply undervoltage lockout protection (UVLO). When the V5IN (PWP) voltage or V5FILT
(RGE) voltage is lower than UVLO threshold voltage, SMPS, VTTLDO and VTTREF are shut off. This is a
non-latch protection.
Add a ceramic capacitor with a value between 1.0 µ F and 4.7 µ F placed close to the V5IN (PWP) pin or V5FILT
(RGE) pin to stabilize 5 V from any parasitic impedance from the supply.
TPS51116 monitors the temperature of itself. If the temperature exceeds the threshold value, 160 ° C (typ),
SMPS, VTTLDO and VTTREF are shut off. This is a non-latch protection and the operation is resumed when the
device is cooled down by about 10 ° C.
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