Datasheet

TPS40200
8
5
VDD
GND
Run
+
545 kW
200 kW
1.3 V
36 kW
+
UDG-05082
TPS40200
SLUS659F –FEBRUARY 2006–REVISED MARCH 2012 www.ti.com
MOSFET Gate Drive
The output driver sinking current is approximately 200 mA and is designed to drive P-channel power FETs. When
the driver pulls the gate charge of the FET it is controlling to –8 V, the drive current folds back to a low level so
that high-power dissipation only occurs during the turn-on period of the FET. This feature is particularly valuable
when turning on a FET at high input voltages where leaving the gate drive current on would otherwise cause
unacceptable power dissipation.
Undervoltage Lockout Protection
Undervoltage lockout (UVLO) protection ensures proper startup of the device only when the input voltage has
exceeded minimum operating voltage. Undervoltage protection incorporates hysteresis which eliminates hiccup
starting in cases where input supply impedance is high.
Figure 28. Undervoltage Lockout
Undervoltage protection ensures proper startup of the device only when the input voltage has exceeded
minimum operating voltage. The UVLO level is measured at the VDD pin with respect to GND. Startup voltage is
typically 4.3 V with approximately 200 mV of hysteresis. The device shuts off at a nominal 4.1 V. As shown in
Figure 28, when the input V
DD
voltage rises to 4.3 V , the 1.3 V comparator’s threshold voltage is exceeded and
a RUN signal occurs. Feedback from the output closes the switch, and shunts the 200 kΩ resistor so that an
approximately 200-mV lower voltage, or 4.1 V, is required before the part shuts down.
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