Floating, High-Voltage Active Rectifier Controller

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.

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

* 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