DESCRIPTION

The LT4322 is a floating active rectifier controller that

drives an external N-Channel MOSFET to replace a

rectifier diode. It is designed primarily for AC

applications and operates with input supply frequencies

ranging from DC to 100kHz. On each cycle of the input

AC waveform, an external N-Channel MOSFET gate is

enhanced to provide the equivalent of a low diode

forward voltage drop of 25mV. The resulting reduction

in power dissipation eliminates thermal design

problems and costly heat sinks, greatly reducing PC

board area.

The addition of a high-voltage depletion N-Channel

MOSFET enables operation at very high output voltages,

limited only by the voltage ratings of two external

MOSFETs. In AC applications, an integrated LDO

provides the required gate drive voltage to turn the

external MOSFET fully on. Fast, high-current gate drivers

minimize reverse current transients at high input frequencies.

FEATURES

? Replaces Rectifying Diodes with N-Channel

MOSFETs in Rectifier Applications

? Maximizes Power Efficiency, Eliminates Thermal

Design Problems

? Low 25mV Forward Voltage Drop

? Wide Operating Voltage Range: 9V to >500V

? Wide Operating Frequency Range: DC to 100kHz

? Regulated 12V GATE Drive for External N-Channel

MOSFET Enhancement

? 8-Lead MSOP and 8-Lead, 3mm x 3mm, Side Wettable

DFN Packages

APPLICATIONS

? Single-Phase, 3-Phase, and 6-Phase Bridge

Rectifiers

? Automotive Alternator Bridge Rectifiers

? Off-Line Active Bridge Rectifier

? 3-Phase Aircraft Power

? High-Voltage DC Diode-OR with Reverse Blocking