Linear Technology Corporation is now making a low loss 3-phase ideal diode bridge rectifier reference design available—which is demonstrated on evaluation board DC2465.
Three-phase diode bridge rectifier reference design based on three LT4320 diodes. Source: Linear Technology
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, which dramatically reduces 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 9 VRMS to 48 VRMS with frequencies up to 400 Hz while sourcing a load of up to 25 A without forced airflow. Efficiency at 9 V input is raised from 84% for a diode bridge to 97% for the active bridge.
The DC2465 evaluation board is available for $125.00 each. The LT4320 ideal diode bridge controller IC is offered in 8-pin MSOP, PDIP and 3 mm x 3 mm DFN packages.
