When selecting DC/DC converters for medical applications, it’s important to remember that power products typically used in medical designs can potentially harm a patient. Power products that meet IEC 60601 medical standards are designed with patient protection in mind. IEC 60601, Part I contains specifications and values that can prevent patients from incurring accidental electrical shock. Two of the three main specifications — isolation voltage, and creepage or clearance distances — are covered here.
In addition to considering power products that offer isolation protection between the electrical circuits and equipment that may contact the device, designers should also be aware of a third specification: Leakage currents, also known as touch currents. They’re the leakage paths from an enclosure that may contact a patient or operator. Because medical patients are often in a weakened state, even a small amount of leakage current can cause them harm. The standard specifies maximum levels of 100 µA for normal operation and 500 µA for a single fault condition.
DC/DC Converter Family Offers Exceptional Leakage Current Characteristics and Satisfies EN60601-1
One particularly good example of a DC/DC converter series that meets IEC 60601, Part 1 is Polytron Devices’ recently introduced MTWA2 and MTWA4 2-watt and 3.5-watt devices. Not only do these DC/DC converters with 2:1 input range exhibit a low leakage current of 2 µA, they offer 5000V AC input to output isolation and the highest level of patient protection — 2 x MOPP. Thanks to process efficiencies that result in a lower cost versus previous DC/DC converters, this series is a desirable option for portable devices with low wattage requirements.
The MTWA2 and MTWA4 Series DC/DC converters with 2:1 input range are both available in 4:1 input versions — MTWB2 (2 watts) and MTWB4 (3.5 watts), respectively. Additional features and specifications include:
- 2:1 wide input voltage range: 4.5V to 12V DC input; 9V to 18V DC and 18V to 36V DC and 36V to 75V DC.
- Efficiency as high as 82 percent.
- Over voltage, short circuit and under voltage protection.
- Availability in miniature DIP16 and SMD16 packages.
- RoHS compliance to 2011/65/EU.
Medical Device Designers Can Realize Cost-Effective Performance and Patient Safety
Power products that meet IEC 60601, Part 1 are designed to protect patients from risk of accidental shock. When specifying DC/DC converters, be sure to look for products that meet this specification while exhibiting low leakage current. Polytron Devices’ MTWA2 and MTWA4 Series DC/DC converters offer low wattage, low cost and excellent patient protection characteristics to give designers of portable medical devices exceptional performance, efficiency and peace of mind.
For more information about Polytron Devices MTWA2 and MTWA4 Series DC/DC converters, visit http://polytrondevices.com/applications/medical.