ZHCSHI4D January 2018 – December 2019 TPS25221
PRODUCTION DATA.
The TPS25221 is current-limited, power-distribution switch using N-channel MOSFETs for applications where short circuits or heavy capacitive loads are encountered. The TPS25221 allows the user to program the current limit threshold between 275 mA to 2.7A (typical) through an external resistor.
This device incorporates an internal charge pump and the gate drive circuitry necessary to drive the N-channel MOSFET. The 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 2.5 V and requires little supply current. The driver controls the gate voltage of the power switch. The driver incorporates circuitry that controls the rise and fall times of the output voltage to limit large current and voltage surges and provides built-in soft-start functionality.
The TPS25221 limits the output current to the current-limit threshold IOS during an over-current or short-circuit event by reducing the charge pump voltage driving the N-channel MOSFET and operating it in the saturation region. The result of limiting the output current to IOS reduces the output voltage at OUT because N-channel MOSFET is no longer fully enhanced (see Figure 22).