TDK Reports Their New AC-DC Power Supplies Peaking at 600 Watts

February 27, 2020 by Gary Elinoff

TDK-Lambda claims their new AC-DC power supplies feature efficiencies up to 96% within an industry-standard 3 x 5-inch footprint.

TDK Corporation recently announced a new series of AC-DC power supplies from their TDK-Lambda brand. All members of the new series, CUS600M, are certified for operation with no earth ground, as per medical and ITE (Information Technology Equipment) standards for Class I and II operation. 

TDK offers seven versions, supplying output voltages ranging from 12 V to 48 V.



The CUS600M series of medical and industrial power supplies. Image used courtesy of TDK-Lambda


All seven versions accept inputs ranging from 85 VAC to 264 VAC, making them suitable for worldwide deployment. With the output inhibited, they draw less than 0.6 W no load.


Model selection for members of the CUS600M

Model selection for members of the CUS600M series. Image (modified) used courtesy of TDK-Lambda


Power good signal is standard, as are remote sense and remote on/off and a 5 V, 2 A standby voltage.


Size and Derating Features

In addition to the open frame versions, which measure 76.2 mm x 127 mm x 37 mm (3 x 5 x 1.46 in.), the units are also available with a cover and a fan option. These versions are slightly larger, though, measuring at 85 mm x 157 mm x 42.5 mm.


CUS600M series with cover and fan

CUS600M series with cover and fan. Image (modified) used courtesy of TDK-Lambda


When convection is cooled, the units can deliver 400 W and a 600 W peak in a -20°C to +40°C ambient environment. They derate linearly to a 200 W load at +70°C. Here, derating is to 420 W at +70°C.


Isolation and Safety Certifications

Isolation and safety certifications are critical considerations for medical devices. 

Members of the CUS600M series all feature:

  • Input to output isolation of 4,000 VAC with two means of patient protection (MOPP)
  • Input to ground isolation of 2,000 VAC with one MOPP
  • Output to ground isolation of 1,500 VAC with one MOPP, suitability in B- and BF-rated medical equipment
  • Leakage current is < 200 µA 
  • Touch current is <100 µA

The devices also pass a number of safety certifications, including:

  • IEC 60601-1-2 immunity
  • IEC 61000-4 immunity
  • IEC/EN/UL 62368-1 safety agency certification (pending)
  • EN 55032 and EN 55011-B conducted and radiated EMI
  • EN 61000-3-2 Class A harmonic compliance


Electrical Considerations

Line regulation is within 0.5% over the entire 85 VAC to 264 VAC input range, and load regulation is 1% over the full 0 to 100% load. 

Ripple and noise for the 12 V unit is 240 mV.

For the 19 V, 24 V, and 28 V family members, the figure rises to 360 mV.

For the 32 V, 36 V, and 48 V versions, ripple and noise are 480 mV, maximum.


Derating vs. input voltage of CUS600M

Derating vs. input voltage of CUS600M. Image used courtesy of TDK-Lambda

Overvoltage and overtemperature protection is provided. Hiccup mode overcurrent protection kicks in at 105% with automatic recovery.

The series is not compatible with parallel operation, but is compatible with the series operation.


Geared for Healthcare and Industrial Industries

Members of this family are aimed at a number of healthcare applications—for instance, for medical and dental products and home healthcare devices. Designers might also find these power supplies useful for test and measurement equipment, broadcasting and communication applications, and professional audio equipment. 

TDK has also identified industrial equipment and LED lighting as a possible application for the CUS600M series.


Around the Industry

The demand for medical devices is high, and TDK's AC-DC power supplies for such devices is in good company.  

Belfuse’s MCC600 series of 600 W medical power supplies operate from an 85 VAC to 264 VAC input range. Available outputs range from 12 VDC to 58 VDC. The units are approved to EN/IEC 60601-1 and provide two MOPP for Class I & Class II applications. 

The PFC600PCX 600 W medical grade power supply from RAM Technologies can work with input voltages ranging from 100 VDC to 250 VDC and output voltages of +12, +5, +3.3, -12 are available. The unit also adheres to a host of medical standards.