Datasheet
Current Sense
Thermal Sense
Undervoltage Lockout
Discharge Function
TPS2062-1
TPS2065-1
TPS2066-1
SLVS714A – FEBRUARY 2007 – REVISED MARCH 2009 ................................................................................................................................................
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A sense FET monitors the current supplied to the load. The sense FET measures current more efficiently than
conventional resistance methods. When an overload or short circuit is encountered, the current-sense circuitry
sends a control signal to the driver. The driver in turn reduces the gate voltage and drives the power FET into its
saturation region, which switches the output into a constant-current mode and holds the current constant while
varying the voltage on the load.
The TPS206x-1 implements a thermal sensing to monitor the operating temperature of the power distribution
switch. In an overcurrent or short-circuit condition the junction temperature rises. When the die temperature rises
to approximately 140 ° C due to overcurrent conditions, the internal thermal sense circuitry turns off the switch,
thus preventing the device from damage. Hysteresis is built into the thermal sense, and after the device has
cooled approximately 10 degrees, the switch turns back on. The switch continues to cycle off and on until the
fault is removed. The open-drain false reporting output ( OCx) is asserted (active low) when an overtemperature
shutdown or overcurrent occurs.
A voltage sense circuit monitors the input voltage. When the input voltage is below approximately 2 V, a control
signal turns off the power switch.
When the device is disabled (when enable is deasserted or during power-up power-down when V
I
< UVLO) the
discharge function is active. The discharge function offers a resistive discharge path for the external storage
capacitor. This is suitable only to discharge filter capacitors for limited time and cannot dissipate steady state
currents greater than 8 ma.
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