Medical Power Supplies

Due to the high-risk nature of medical applications, the corresponding electronic equipment must be held to very high standards of safety and reliability. Our modular REM and RACM series converters offer complete, compliant solutions that reduce design time, simplify end-user certification and provide faster time to market. These medical grade DC/DC converters and AC/DC power supply series feature reinforced isolation with two means of patient protection (2MOPP), low leakage (BF and CF ratings) and > 8mm creepage and clearance distances. Reinforced isolation provides an additional level of safety beyond the standard functional isolation to comply with the medical safety standard ES/IEC/EN 60601-1 3rd Ed.

It is an energy source that has to possess properties that need to meet the necessary standards for medical use in a hospital or residential home. The worldwide ES/IEC/EN 60601-1 3rd Ed. standard provides us with guidelines, which are more stringent compared to guidelines for commercial or industrial appliances. Higher safety standards and lower electromagnetic interference are required, providing EMC Compliance.

What to consider for complying with ES/IEC/EN 60601-1 3rd Ed.?

The 3rd edition of IEC 60601 focuses on the safety of operating personnel and patients. To assess medical electrical equipment, a new classification system (MOP — means of protection) has been introduced.

When electronic devices do not come into direct contact with the patient and are only handled by trained operators they are classified in category MOOP, which means they typically only need to meet 60950-1 and 62368-1 ITE standards for Laboratory Environment Compliance.

The product falls into category MOPP when there will be direct physical contact between the device and the patient and then must meet extremely stringent safety standards, especially in regards to insulation.

To protect patients against electric shock, such products must feature two separate insulation barriers. The closer the contact between the device and the patient, the lower the permissible leakage current. Application devices are therefore classified according to the type of contact to the patient.

We all know that electric currents through the body are extremely dangerous and often result in death. For a healthy person, currents as low as 40mA could be fatal. For a person who is anaesthetised or weakened by an illness, this threshold is likely to be much lower.

To protect patients, power supplies for medical devices must meet stringent requirements in regards to leakage and stray currents. The limit values vary depending on the type and nature of the applied part (AP) that is brought into direct contact with the patient's body.

Although the power supply meets both leakage-current and isolation, the ended system is still required to further evaluate and confirm the compliance with the patient environment.

• Type B (Body)
  No direct physical contact with patient. Examples: LED lighting in operating theatres, medical laser units, etc.
• Type BF (Body Float)
  Physical contact with patient, or risk to patient from device failure. Examples: Incubators, ultrasonic devices, diagnostic equipment, etc.
• Type CF (Cardiac Float)
  Direct contact to patient's heart, risk of injury or death in the event of device failure. Examples: Defibrillators, heart-lung machines, etc.
• Power supplies for BF & CF applications
  Medical power supplies for type BF & CF medical devices are designed to provide 2MOPP of input to output isolation.

When it comes to life-supporting or life-saving devices, faults and malfunctions caused by electromagnetic or radio interference could obviously be fatal. The failure criteria of the IEC60601-1-2 in regards to electromagnetic interference and electromagnetic immunity must be taken into account in the risk management.

The 4th edition of the IEC standard on EMC stipulates much more stringent requirements as regards electromagnetic immunity than its ancestor. Equipment must now be immune to HF fields up to 2.7GHz, an increase by 0.2GHz. In addition, the standard wants to prevent damage caused by electrostatic discharge, and the relevant limits have been increased accordingly. For contact discharge, the threshold went up from 6 to 8kV. For air discharge, it has been increased from 8 to 15kV.

In order to meet the above requirements, in particular in regards to insulation and leakage currents, a combination of high-quality medical-grade AC/DC power supplies and DC/DC converters is often the most efficient solution. This approach makes it easier to meet the stringent requirements of double patient protection (2MOPP).

We offer a broad range of products that are certified for use in medical electrical equipment. Apart from DC/DC converters from 1 to 30W, we also manufacture AC/DC power supplies with up to 1200W. They are certified to EN/ES 60601-1 3rd edition, EN/UL 60950-1 and EN/UL 62368-1, and do not contain any hazardous substances according to the RoHS2 and REACH Directives. Another plus is the 5-year warranty that we grant on all these products.

The REM3, REM6 and REM10 medical grade regulated DC/DC converters feature 250VAC working voltage, up to 5kVAC/1 minute reinforced isolation and low 2µA leakage. An optional external control pin brings standby consumption down to only 12.5mW.

The reliable REM15-W, REM20-W and REM30-W series offer well balanced specifications for critical medical applications, while guaranteeing far-reaching compatibility with their extra-wide 4:1 input voltage range at compact case sizes of only 1.6”x1” and 2”x1”.

Due to the innovative design of the RxxPxx/R and RxxP2xx/R series we are also able to offer medical DC/DC converters with an extended reinforced isolation of up to 8kVDC suitable for high voltage applications.

The REM1, REM2, REM3.5E, REM5E and REM6E series feature reinforced 250VAC continuous working isolation with >8mm creepage/clearance providing 2MOPP. These converters offer all key features required for critical medical applications, while keeping the cost of these modular solutions down. They are available with pins as well as SMD.

Our RACM series are highly efficient 6W to 1200W AC/DC power supplies with 2MOPP safety approval for mains-powered medical applications. These power supplies have a universal AC input voltage range, 4kVAC isolation, low standby power consumption, active PFC (> 0.95) and do not require a minimum load.