NCP372

http://onsemi.com

8

Operation

The NCP372 provides overvoltage protection for

positive and negative voltages, up to 28 V or down to

−28 V. The negative protection is ensured by an internal

NMOS FET protects the systems (i.e.: charger) connected

input overtakes the undervoltage UVLO (Figure 3). The

NCP372 provides a FLAG output, which alerts the system

seconds after the output signal rises. FLAG pin is an open

drain output.

Undervoltage Lockout (UVLO)

To ensure proper operation under any condition, the

device has a built−in undervoltage lockout (UVLO) circuit.

UVLO threshold. This circuit has a built in hysteresis to

Overvoltage Lockout (OVLO)

overvoltage, the device has a built−in overvoltage lockout

(OVLO) circuit. During overvoltage condition, the output

remains disabled until the input voltage exceeds 6.3 V.

This circuit has a built in hysteresis to provide noise

FLAG Output

The NCP372 provides a FLAG output, which alerts

external systems that a fault has occurred.

This pin goes low as soon the OVLO threshold is

response. The pin is an open drain output, thus a pullup

resistor (typically 1.0 M

W, minimum 10 kW) must be

status, even if the device is turned off (EN = 1).

EN Input

To enable normal operation, the EN pin shall be forced

low or connected to ground. A high level on the pin,

disconnects OUT pin from IN pin. EN does not overdrive

an OVLO or UVLO fault.

Negative Voltage and Reverse Current

The built−in NMOS protects the downstream system

from negative voltages occurring on IN pin down to −28 V.

The same NMOS avoids reverse currents that could

discharge the battery.

When a fault occurs, the output is disconnected from IN

pin and FLAG goes low.