EFE Series Medical Power Supplies

TDK-Lambda has extended the power range of their digitally-controlled EFE-M series of medical/ITE power supplies from 300 W to 400 W. The EFE400M series was designed with Medical and ITE applications in mind. With a 4 kVAC reinforced input to output isolation and an output-to-ground isolation of 1500 VAC, the EFE400M meets the rigorous international safety standards of IEC/UL 60601-1 for medical equipment, making it suitable for use in B (body) and BF (body floating) type medical and dental applications. Regulated DC outputs of 12 V, 24 V, or 48 VDC are standard, plus other voltages can be provided.

With a 3.5 x 6.5 inch footprint and less than a 1U profile (1.34" to 1.60") the EFE400M can be incorporated easily into designs where space is limited so the end product can be smaller and cooler. Other features such as a redundant operation capability, a standby voltage output and ITE safety certifications per IEC/UL 60950-1, make the EFE400M equally suitable for high-integrity applications (in addition to medical) including broadcast, instrumentation, routers, servers, security networks, ATE, and factory automation.

The EFE400M series includes an integrated magnetics transformer (transformer and inductor windings on the same core) to boost efficiency to typically 90 percent and employs an 8-bit microcontroller for full digital control of the output and to handle housekeeping routines. This resulted in a 25 percent parts count reduction to achieve a 45 percent smaller and up to 56 percent lighter design when compared to similar competitive products. Power densities of up to 15.6 W/in3 are achieved under peak load conditions and 13.1 W/in3 under continuous loading.

TDK-Lambda's control of the EFE400M allows the power supply's performance, such as current limit and start-up characteristics, to be optimized digitally – this feature eliminates the hardware changes usually required in analog designs. A reduced cost primary side control topology is employed, supervised by the microcontroller. This results in fewer parts and higher efficiency without sacrificing load regulation performance. Furthermore, the need for an opto-isolator is eliminated – a device that is undesirable for long life power supply designs.

Additional features of the EFE400M include remote on/off and power-good signals; it also comes with a 5 V/2 A isolated standby output, which is not affected by the remote on/off. The inclusion of an ORing FET allows redundant operation of EFE400M supplies with no external diodes required.