ISL6144_07 Datasheet, PDF (1/29 Pages) Intersil Corporation – High Voltage ORing MOSFET Controller

®
Data Sheet
February 15, 2007
ISL6144
FN9131.3
High Voltage ORing MOSFET Controller
The ISL6144 ORing MOSFET Controller 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.
In a multiple supply, fault tolerant, redundant power distribution
system, paralleled similar power supplies contribute equally to
the load current through various power sharing schemes.
Regardless of the scheme, a common design practice is to
include discrete ORing power diodes to protect against reverse
current flow should one of the power supplies develop a
catastrophic output short to ground. In addition, reverse current
can occur if the current sharing scheme fails and an individual
power supply voltage falls significantly below the others.
Although the discrete ORing diode solution has been used for
some time and is inexpensive to implement, it has some
drawbacks. The primary downside is the increased power
dissipation loss in the ORing diodes as power requirements for
systems increase. Another disadvantage when using an ORing
diode would be failure to detect a shorted or open ORing diode,
jeopardizing power system reliability. An open diode reduces
the system to single point of failure while a diode short might
pose a hazard to technical personnel servicing the system
while unaware of this failure.
The ISL6144 can be used in 10V to 75V systems having similar
power sources and has an internal charge pump to provide a
floating gate drive for the N-Channel ORing MOSFET. The High
Speed (HS) Comparator protects the common bus from
individual power supply shorts by turning off the shorted feed’s
ORing MOSFET in less than 300ns and ensuring low reverse
current.
An external resistor-programmable detection level for the HS
Comparator allows users to set the N-Channel MOSFET
“V_OUT - V_IN” trip point to adjust control sensitivity to power
supply noise.
The Hysteretic Regulating (HR) Amplifier provides a slow turn-
off of the ORing MOSFET. This turn-off is achieved in less than
100μs when one of the sourcing power supplies is shutdown
slowly for system diagnostics, ensuring zero reverse current.
This slow turn-off mechanism also reacts to output voltage
droop, degradation, or power-down.
An open drain FAULT pin will indicate that a fault has occurred.
The fault detection circuitry covers different types of failures;
including dead short in the sourcing supply, a short of any two
ORing MOSFET terminals, or a blown fuse in the power
distribution path.
Features
• Wide Supply Voltage Range +10V to +75V
• Transient Rating to +100V
• Reverse Current Fault Isolation
• Internal Charge Pump Allows the use of N-Channel
MOSFET
• HS Comparator Provides Very Fast <0.3µs Response
Time to Dead Shorts on Sourcing Supply. HS Comparator
also has Resistor-adjustable Trip Level
• HR Amplifier allows Quiet, <100µs MOSFET Turn-off for
Power Supply Slow Shut Down
• Open Drain, Active Low Fault Output with 120µs Delay
• Provided in Packages Compliant to UL60950 (UL1950)
Creepage Requirements
• QFN Package:
- Compliant to JEDEC PUB95 MO-220
QFN - Quad Flat No Leads - Package Outline
- Near Chip Scale Package footprint, which improves
PCB efficiency and has a thinner profile
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
• ORing MOSFET Control in Power Distribution Systems
• N + 1 Redundant Distributed Power Systems
• File and Network Servers (12V and 48V)
• Telecom/Datacom Systems
Ordering Information
PART
PART
NUMBER MARKING
TEMP.
RANGE
(°C)
PKG.
PACKAGE DWG. #
ISL6144IV* ISL61 44IV -40 to +105 16 Ld TSSOP M16.173
ISL6144IVZA* ISL61 44IVZ -40 to +105 16 Ld TSSOP M16.173
(See Note)
(Pb-Free)
ISL6144IR* ISL 6144IR -40 to +105 20 Ld 5x5 QFN L20.5x5
ISL6144IRZA* ISL6144 IRZ -40 to +105 20 Ld 5x5 QFN L20.5x5
(See Note)
(Pb-Free)
NOTE: Intersil Pb-free plus anneal products employ special Pb-free
material sets; molding compounds/die attach materials and 100% matte
tin plate termination finish, which are RoHS compliant and compatible
with both SnPb and Pb-free soldering operations. Intersil Pb-free
products are MSL classified at Pb-free peak reflow temperatures that
meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
*Add “-T” suffix for tape and reel.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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