TPS2041B-Q1
TPS2042B-Q1
TPS2051B-Q1
SLVS782A –NOVEMBER 2007–REVISED JUNE 2010
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Enable (EN)
The logic enable disables the power switch and the bias for the charge pump, driver, and other circuitry to reduce
the supply current. The supply current is reduced to less than 1 mA or 2 mA when a logic low is present on EN. A
logic high input on EN restores bias to the drive and control circuits and turns the switch on. The enable input is
compatible with both TTL and CMOS logic levels.
Overcurrent (OCx)
The OCx open-drain output is asserted (active low) when an overcurrent or overtemperature condition is
encountered. The output remains asserted until the overcurrent or overtemperature condition is removed. A
10-ms deglitch circuit prevents the OCx signal from oscillation or false triggering. If an overtemperature shutdown
occurs, the OCx is asserted instantaneously.
Current Sense
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.
Thermal Sense
The TPS204xB/TPS205xB 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.
Undervoltage Lockout (UVLO)
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.
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