Low-leakage power supplies target medical applications

The OFM30 Series of 30W extra low-leakage power supplies has been introduced by Powerbox, expanding its Medline offering. The newcomers offer best-in-class EMC performance for medical systems in CF class. Also, the OFM225 225W Series which targets BF class applications has been expanded with additional voltages. Designed to meet and exceed new safety standards for medical systems and equipment, and based on an innovative building practice, reducing leakage current below 10µA and EMC, the new OFM30 series delivers 30W in continuous operation (peak up to 45W) features Class II double isolation and is UL/IEC60601-1 medically approved. Trying to achieve low leakage current with low EMC is a difficult challenge. Based on an innovative design, the OFM30 combines both, reaching a leakage current below 10µA and an EMC Class B average margin of 6dB. Combining low power loss switching topology and selected components, the OFM30 series has an efficiency up to 88% while, fulfilling the Green Mode requirements of IEC60950-1, CEC Level V, EISA and ErP, at zero load. The OFM30 power consumption is below 0.3W thus assuring the family of its green credentials. The OFM30 output power is rated at 30W continuously, at 50C and free convection cooling; though it can respond to peak demands for extra power (e.g. pump systems), allowing up to 45W during 10 seconds, with repetition every 100 seconds. In case of over temperature, the OFM30 integrates a novel protection system operating with linearity, reducing the output power down to 50%, securing the payload to proceed to all appropriated processes to avoid treatment disruption. Addressing medical applications demands high reliability, the OFM30 exploits the benefits of a switching topology based on a front-edge fly-back, optimized to reduce components count down to 65. This lower number of components contributes to higher reliability, resulting in an MTBF over 500,000 hours and a minimum lifetime expectation of 80,000 hours. The OFM30 series includes three models: the OFM305025 delivering 12V / 2.5A (peak 3.75A), the OFM305026 delivering 15V / 2.0A (3A peak), and the OFM305028 delivering 24V / 1.25A (peak 1.875A). In case of a need for redundancy or extra power, all products can be connected in parallel without any additional external components. The product is available in an open frame format of 75.5mm x 37.3mm x 23mm (3 x 1.5 x 0.9 inch). The OFM30 series is safety approved according to IEC 60601-1 ed.3, with CB’s by ETL Intertek Semco, and complies with other related IEC 61000 applicable standards and environmental norms RoHS, REACH and WEEE, says the company. “Safety in medical applications is a must, it is particularly important when designing power supplies for Cardiac Floating (CF) applications, when electrically connected to the heart of the Patient, to guarantee the highest level of security” said Martin Fredmark, VP product management, Powerbox. “Reducing the leakage current is always an important step forward and we are permanently working on new technologies to improve patient safety.” In addition to the new Medline OFM30, Powerbox expands its market leading Medline OFM225 with two additional voltages, the OFM2255225 delivering 12V / 11.25A (peak 21.66A), and the OFM2255226 delivering 15V / 6.66A (19A). With a high degree of focus on reliability, using ‘One Step Conversion’ topology, which integrates a PFC delivering high performance at only 50% load, the OFM225 has the ability to safely operate in low airflow conditions, delivering 225W at 40C ambient in natural convection and up to 325W continuous at 12 CFM forced air cooling. The unit can also be operated in parallel mode and includes advanced protection for business continuation. Intended for type BF applications the unit can withstand 4000VAC from input to both output and ground, has a leakage current of <100µA, and meets class B EMC requirements. Applications include respiratory and anaesthesia dialysis equipment. The Medline 225 OFM225 series meets, amongst others, safety standards IEC 60601-1 and 60950-1, EMC IEC60601-1-2, IEC61204-3, and EN55011 Class B, including corresponding North American versions. It also meets the environmental norms RoHS, REACH and WEEE.