XP Power Launches a Series of 500W Medical Power Supplies
The new units provide Class II safety certification and Body Floating (BF) Class insulation
Members of XP Power’s PBL500 series operate from inputs ranging from 80 to 264 VAC at line frequencies of 47 to 63 Hz. The series includes devices providing single outputs of either 12, 15, 18, 24, 28, 36, 48 or 57 volts. As per the data-sheet, maximum output for the 12 and 15 -volt versions are 450 watts
The PBL500 Series. Image courtesy of XP Power
What are Class II Power Supplies and BF Class Insulation?
As described by Digikey, Body Floating (BF) Class Insulation is relevant to devices that make direct electrical contact with a patient, but not to their hearts. These types of units do not connect to external ground and are thus considered to be “floating.”
The governing standards are defined by IEC 60601-1. They are both complex and specific, and OEMs would do well to give this standard their upmost consideration. There are strict requirements both for current leakage and for creepage distances.
Basic requirements include input to output isolation of 4000 VAC or better. Additionally, there must be at least 1500 VAC isolation for both input to ground and output to ground.
Class II power supplies refer to units that don’t rely on earth grounding for protection against shock hazard. Smartphone chargers are typical examples
Two Mechanical Formats
The Top Fan Cover Version, depicted in the top left corner of the illustration, includes a built-in, low noise variable speed cooling fan. These series members will provide 450 to 500 watts of output power
The U-Channel Version, depicted on the illustration’s lower right, will also offer 450 to 500 watts output when provided with external forced air cooling. With convection cooling, output is 250 watts.
Specific Safety and EMI Concerns and Precautions for the PBL500 series
Because device served by medical power supplies make direct and intimate contact with human being, safety is the number one concern
All units provide 2 x MOPP (means of patient protection) from input to case and from input to output, as well as 1 x MOPP from output to ground. Equivalently, input to case and input to output isolation is specified at 4000 VAC while the output to ground specification is 1500 VAC.
Typical efficiency of the series is 90%. This is specified at full output load and with 230 VAC input.
The maximum switching frequency is 300 kHz.
All members of the series offer:
- Standby power supply of 5 volts
- Remote sensing,
- Overvoltage protection
- Overcurrent protection
- Thermal shutdown
- ‘AC OK’ signal
- Remote on/off control
Additionally, the U Channel devices feature a 12 volt, 0.3 amp output aimed at powering the cooling fan.
Additional Regulatory Information
Members of the series are compliant with:
- IEC/ES/EN 60601-1 edition 3.1
- 60601-1-2 edition 4
Conducted and radiated emissions are both class B.
- The U-channel version measures 7.1 x 4.00 x 1.56” and weighs 2.23 pounds
- Top Fan Cover version measures 7.1 x 4.00 x 2.64” and weighs 2.52 pounds
- Series members operate over a temperature range of -10 to +70 ℃. However, the units derate linearly from 100% to 50% as the temperature increases from +50℃ to +70℃