Quiet 800W mains PSU suits BF-rated medical applications and test

TDK-Lambda has released a 1U high modular ac-dc power supply series from which “the product’s low acoustic noise is desired in test and medical applications where audible disturbances need to be kept to a minimum”, said the company.

Called MU4, the supplies can accept up to five output modules for five isolated regulated outputs, and deliver up to 800W or 600W depending on input voltage (see later). Dimensions are 89 x 41 x 258mm, allowing it to fit in a 1U high rack slot.

To simplify implementation in BF-rated medical applications, all models feature MOPPs (means of patient protection) isolation, including output-to-earth. Use is also foreseen in dental, test, measurement, broadcast, professional audio, and industrial equipment.

There are four standard output module slots and one for a 5V 2A standby output.

Initially, nine modules are available, with overlapping output ranges offering a continuous sweep of outputs from 3.3V to 104V with ratings from 150W to 480W. Higher current modules occupy two slots. Options, some needing a different chassis unit, include: PMBus communication, fan fail signal, inhibit or enable (for individual or all outputs), dc-good and current share for paralleled modules.

With the intelligent fan rotation speed control audible noise can be as low as 36dBA (80% load, with caveats). “Its microcontroller algorithm monitors the temperature of the primary converter and each output module, allowing the fan speed to be adjusted for optimum cooling” said TDK.

Efficiency is up to 90%, and operation is over is over 180 to 264Vac for 800W, or 90 to 180Vac if 600W is acceptable. Further de-rated, it will work from 85Vac. Operation is also over -20°C to +70°C, de-rating linearly to 50% load above 50°C.

Maximum leakage is 300µA – including all tolerances – and touch is <100µA.

Isolations are: 4kVac (2 x MoPP) input-to-output, 1.5kVac (1 x MoPP) input-to-earth and 1.5kVac (1 x MoPP) output-to-earth for B and BF rated medical equipment.

Safety certification is to IEC/EN 60601-1, ES 60601-1, IEC/EN/CSA/UL 62368-1, (IEC/EN 61010-1 designed to meet) and they are CE / UKCA marked to the Low Voltage, EMC and RoHS EU Directives and UK regulations.

EN 55011-B, EN 55032-B radiated and conducted emissions are met, and the models comply with the EN 60601-1-2:2015 (Edition 4) and EN 61000-4 immunity standards.

The MU4 product page can be found here and the data sheet is here