TPS2014, TPS2015
POWER DISTRIBUTION SWITCHES
SLVS159C DECEMBER 1996 REVISED MARCH 2004
3
TI.COM
Terminal Functions
TERMINAL
I/O
DESCRIPTION
NAME
NO.
I/O
DESCRIPTION
EN
4
I
Enable input. Logic low at EN turns the power switch on.
GND
1
I
Ground
IN
2, 3
I
Input voltage
OC
5
O
OC is asserted active low during a fault condition.
OUT
68
O
Power switch output
detailed description
power switch
The power switch is an n-channel MOSFET with a maximum on-state resistance of 95 m
(VI(IN) = 5 V),
configured as a high-side switch.
charge pump
An internal 100-kHz charge pump supplies power to the driver circuit and provides the necessary voltage to pull
the gate of the MOSFET above the source. The charge pump operates from input voltages as low as 4 V and
requires very little supply current.
driver
The driver controls the gate voltage of the power switch. To limit large current surges and reduce the associated
electromagnetic interference (EMI) produced, the driver incorporates circuitry that controls the rise times and
fall times of the output voltage. The rise and fall times are typically in the 2-ms to 4-ms range instead of the
microsecond or nanosecond range for a standard FET.
enable (EN)
A logic high on EN turns off the power switch and the bias for the charge pump, driver, and other circuitry to
reduce the supply current to less than 10
A. A logic zero input restores bias to the drive and control circuits
and turns the power on. The enable input is compatible with both TTL and CMOS logic levels.
overcurrent (OC)
OC is an open-drain logic output that is asserted (active low) when an overload or short circuit is encountered.
The output remains asserted until the overload or short-circuit condition is removed.
current sense
A sense FET monitors the current supplied to the load. The sense FET provides a much more efficient way to
measure current 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 linear region, which switches the output into a constant current mode and simply holds
the current constant while varying the voltage on the load.
thermal sense
An internal thermal-sense circuit shuts off the power switch when the junction temperature rises to
approximately to 180
°C. Hysteresis is built into the thermal sense circuit. After the device has cooled
approximately 20
°C, the switch turns back on. The switch continues to cycle off and on until the fault is removed.
undervoltage lockout
An internal voltage sense monitors the input voltage. When the input voltage is below 3.2 V nominal, a control
signal turns off the power switch.