NCP373

http://onsemi.com

8

EN

FLAG

IN

Vbus

Transciever

tON

Downstream Vbus connection

Battery output

Transciever

DIR

Figure 5. FLAG Status in Vbus Mode

Logic Inputs

To enable Charge operation (Charge Mode), the DIR pin

shall be forced to low and

EN to high. A high level on the

DIR pin disconnects IN pin from Vbus pin. DIR does not

overdrive an OVLO or UVLO fault (FLAG status is still

available).

Table 1. TABLE SELECTION OF CHARGE MODES

DIR

EN

MODE

Protection

OVP @ VBUS (+28 V, −28 V,

OVLO 5.77 V)

OCP (IN to VBUS)

OCP (VBUS to IN)

0

0

NA

NA

NA

NA

0

1

Charge

Yes

NA

NA

1

0

VBUS

Yes

Yes

NA

1

1

Disable

Yes (out off)

NA

NA

Negative Voltage and Reverse Current

The device protects the system connected on IN pin from

negative voltage occurring on Vbus pin, down to −28 V.

When a negative voltage occurs, the IN pins are

disconnected from Vbus pins. This negative protection is

available in all modes

Thermal Shutdown Protection

In case of internal overheating, the integrated thermal

shutdown protection allows to open the internal MOSFET

in order to instantaneously decrease the device temperature.

The thermal threshold has been set at 150

°C. FLAG is then

tied to low to inform the MCU.

As the thermal hysteresis is 30

°C, the MOSFET will be

closed as soon the device temperature falls down to 120

°C.

If the fault event is still present, the temperature increase

one more time and engages the thermal shutdown one more

time until fault event disappeared.