Low Loss 3-Phase Ideal Diode Bridge Rectifier Reduces Heat, Easing Thermal Design

MILPITAS, CA --- Linear Technology Corporation announces the availability of a low loss 3-phase ideal diode bridge rectifier reference design, demonstrated on evaluation board DC2465. Conventional 3-phase rectifiers employ six diodes, but the diodes drop voltage and dissipate significant power at just a few amperes of load current. This requires costly heat sinking and active cooling solutions that complicate thermal design and increase solution size. The DC2465 design replaces the six diodes with three LT4320 ideal diode bridge controllers, driving six low loss N-channel MOSFETs, dramatically reducing power and voltage losses. This enables the overall system to be specified to operate with a smaller, more cost-effective power supply due to the enhanced power efficiency. Low voltage applications benefit from the extra margin afforded by saving the two diode drops inherent in diode bridges. Compared to traditional approaches, the MOSFET bridge enables a rectifier design that is highly space- and power-efficient.

The DC2465 board rectifies line-to-line AC voltages from 9VRMS to 48VRMS with frequencies up to 400Hz while sourcing a load of up to 25A without forced airflow. Efficiency at 9V input is raised from 84% for a diode bridge to 97% for the active bridge.

Summary of Features: DC2465

High Efficiency Rectification of 3-Phase AC Input
Replaces Diodes with Low Loss N-Channel MOSFETs
Minimizes Heat Dissipation, Easing Thermal Design
Maximizes Power Efficiency & Available Voltage
Input Rating
9VAC to 48VAC RMS Line-to-Line Operation
Up to 400Hz Line Frequency
Output Rating
70VDC Maximum Output Voltage
25A Maximum Load without Forced Airflow

The DC2465 evaluation board is available, priced at $125.00 each. The LT4320 ideal diode bridge controller IC is offered in 8-pin MSOP, PDIP, and 3mm x 3mm DFN packages. Evaluation circuit boards are available online or from your local Linear Technology sales office.

For more information, visit http://www.linear.com/demo/DC2465