March 6, 2014 – Linear Technology Korea (CEO Hong Sa-kwak) announced the launch of a perfect diode bridge controller suitable for 9V ~ 72V systems in automotive (H-grade) and high-reliability military (MP-grade) versions (product name: LT4320).

The LT4320 replaces full-wave diode bridge rectifiers with low-loss N-channel MOSFET bridges, reducing power and voltage losses by 10 times or more. With improved power efficiency, there is no need for large heat sinks, resulting in reduced power supply size. In low-voltage applications, by reducing the two diode drops generated by the diode bridge circuit, users benefit from ample additional margin gain. Compared to existing alternative products, the MOSFET bridge realizes very space-efficient and power-efficient rectifier design. The H-grade and MP-grade versions are guaranteed in temperature ranges of −40°C ~ 125°C and −55°C ~ 125°C, respectively.

The LT4320 switch control turns on the appropriate two MOSFETs while keeping the other two off to prevent reverse current. The built-in charge pump provides gate drive for external low on-resistance N-channel MOSFETs without requiring external capacitors. Depending on MOSFET selection, a very flexible power level range from 1W to several thousand watts can be implemented.

The LT4320 is offered in two options. The LT4320 is designed for DC ~ 60Hz voltage rectification, while the LT4320-1 is optimized for DC ~ 600Hz with the top source-drain bias voltage doubled. The H-grade is supplied in 8-pin DFN (3mm x 3mm) and PDIP packages, as well as advanced 12-pin MSOP packages with high-voltage pin spacing. The MP-grade, however, is available only in the 12-pin MSOP package. Device samples and evaluation circuit boards are available from Linear Technology's respective regional offices or online.

Photo caption: −55°C ~ 125°C Rated Active Bridge Rectifier, Power & Voltage Conservation