6

FN9131.7

October 6, 2011

Functional Pin Descriptions

GATE

This is the Gate Drive output of the external N-Channel

MOSFET generated by the IC internal charge pump. Gate

turn-on time is typically 1ms.

VIN

Input bias pin connected to the sourcing supply side (ORing

MOSFET Source). Also serves as the sense pin to

determine the sourcing supply voltage. The ORing MOSFET

will be turned off when VIN becomes lower than VOUT by a

value more than the externally set threshold.

VOUT

Connected to the Load side (ORing MOSFET Drain). This is

the VOUT sense pin connected to the load. This is the

common connection point for multiple paralleled supplies.

VOUT is compared to VIN to determine when the ORing

FET has to be turned off.

HVREF

Low side of the internal IC High Voltage Reference used by

internal circuitry, also available as an external pin for

additional external capacitor connection.

COMP

This is the high side connection for the HS Comparator trip

externally set the desired level depending on particular

system requirement.

VSET

Low side connection for the HS Comparator trip level setting

FAULT

Open-Drain pull-down FAULT Output with internal on-chip

pull-down this pin to GND as soon as it detects a fault.

Different types of faults and their detection mechanisms are

discussed in more detail in the “Functional Block Description”

on page 6.

GND

IC ground reference.

Detailed Description

The ISL6144 and a suitably sized N-Channel power

MOSFET(s) increases power distribution efficiency and

availability when replacing a power ORing diode in high current

applications. Refer to “Application Considerations” on page 8

for power saving when using ISL6144 with an N-channel ORing

MOSFET compared to a typical ORing diode.

Functional Block Description

Regulating Amplifier-Slow (Quiet) Turn-off

A Hysteretic Regulating (HR) Amplifier is used for a

Quiet/Slow turn-off mechanism. This slow turn-off is initiated

when the sourcing power supply is turned off slowly for

system diagnostics. Under normal operating conditions as

HR Amplifier regulates the gate voltage to keep the 20mV

(Vs - Vd). This will continue until the load current exceeds

the MOSFET ability to deliver the current with Vsd of 20mV.

In this case, Gate will be charged to the full charge pump

the MOSFET will be fully enhanced and behave as a

output of the HR Amp is pulled high and the gate is pulled

ORing FET is turned off, avoiding reverse current as well as

voltage and current stresses on supply components.

-

5.3

-

V

Fault Low Output Voltage

--

0.5

V

Fault Sink Current

4

--

mA

Fault Leakage Current

--

10

µA

Fault Delay - Low to High

-120

-

µs

NOTES:

12. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.

Electrical Specifications

temperature range, -40°C to +105°C.

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

(Note 12)

TYP

MAX

(Note 12) UNITS

ISL6144