100W single output AC-DC power supplies have medical approvals

October 30, 2014 // By Graham Prophet
TDK-Lambda’s ZMS100 is the first unit in the ZM series of sub-300W power supplies. Designed and developed in the UK, the ZMS100 single-output power supply conforms to the new IEC60601-1 3rd edition medical standard with input to output isolation of 4 kVac and 2 x MOPP (means of patient protection).

Both input to ground and output to ground isolation levels are 1.5 kVac 1 x MOPP. With a 2 x 4-in. footprint and less than 100 µA touch current, the ZMS100 is suitable for both Class I and Class II (or double insulated) applications meeting the safety requirements for hospital, clinical, dental and home based medical environments.

The design has maximised electrolytic capacitor lifetime; for example, minimising ripple current in output capacitors (which causes internal heating) and ensuring good airflow around the components. A longer life ceramic type is used for the start-up capacitor rather than the commonly used electrolytic.

In addition to medical applications, these supplies are equally well-suited to broadcast and professional audio applications; they can be convection-cooled at outputs of 80W and below, so no fan is required and therefore no audible noise is present.

The ZMS100 range covers all commonly used output voltages from 12 to 48V with 90% typical efficiency, and meets ErP guidelines with less than 0.5W no load power consumption and an average active efficiency of greater than 87%. To accommodate non-standard system voltages, the ZMS100 is user adjustable by -5/+10%. Operating from a universal input, the ZMS100 power supply can deliver up to 80W at 50°C under convection cooling and 100W at 50°C in forced air (only requiring a low airflow of 0.37 m/sec at 230 Vac input).

All models in TDK-Lambda's ZMS100 range meet conducted EMI requirements of EN55011-B and FCC Class B (without additional filtering or components) and EN60601-1-2 immunity specifications for greater reliability. The ZMS100 carries the CE mark, according to the LV and RoHS2 Directives, and comes with a 3-year warranty.

TDK-Lambda; www.uk.tdk-lambda.com/zms