NCP370 ON Semiconductor, NCP370 Datasheet - Page 8

• Manufacturer Part Number: NCP370
• Description: Positive and Negative Overvoltage Protection
• Manufacturer: ON Semiconductor

Negative Voltage and Reverse Current.
voltage occurring on the IN pin, down to −28 V. When a
negative voltage occurs, the output is disconnected from the
IN pins.
Reverse Mode
bottom connector can be powered by the internal battery of
the system.
(> 1.2) and REV must be tied high to low (< 0.55 V).
battery, with a 2.5 V minimum voltage and 5.5 V maximum
voltage.
available.
Overcurrent Protection (OCP)
function, from battery to external accessory.
limited when the value, set by the external R
exceeds I
allowing a maximum OCP value when I
connected to GND.
The device protects the downstream side from negative
In Reverse Mode, an external accessory plugged into the
To access to the reverse mode, DIR pin must be tied high
In this case, the core of the NCP370 will be supplied by the
In this reverse state, both OCP and thermal modes are
This device integrates the reverse over current protection
That means the current across the internal NMOS is
An internal resistor is placed in series with the I
OCP
.
FLAG
REV
I
V
DIR
REV
out
ID
V
in
ton
REV
Figure 5. Overcurrent Protection Sequence
lim
tstart
pin is directly
Drive Current in Accessory
limit
REV
resistor,
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lim
t
RRD
pin
t
REG
8
the OCP value is lowered. See below table:
and FLAG output goes low, allowing the micro−controller
to process the fault event and then disable reverse charge
path.
current is limited up to I
capacitor charge and limit inrush current. If the I
threshold is exceeded over 1.2 ms, the device enters
OCP burst mode until the overcurrent event disappears.
mode is engaged. See Figure 5.
Table 3. OVERCURRENT THRESHOLD SELECTION
By adding external resistors in series from I
Typical Current clamp table:
During an overcurrent event, the N−MOSFETs turn off
At power up (accessory is plugged on input pins), the
After 1 ms following the plug in of the accessory, the OCP
OCP
(A)
1.6
1.0
0.5
Accessory ID
Detection
lim
for 1.2 ms (typical), to allow
I
lim
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R
(kW)
LIMIT
14
70
0
lim
to GND,
lim