Introduction of Medical Grade Modular Power Supply

By:Willard Wu /Technical Dept.

In recent years, the electronics industry has developed rapidly, and the types and functions of electronic products have become more and more diverse. Even medical equipment has become more and more diversified. A medical-related system may contain several different driving voltages, and the demand for total wattage increases as well. In the early days, customers could only use multiple numbers of medical power suppliers. However, now customers can have different choices. They can choose MEAN WELL NMP650/ 1K2 medical-grade modular power supply or UMP-400 series, in compliance with medical regulations.
UMP-400 series is a 1U low profile module power supply. Its flexible and modular design makes it an unrivaled type of power supply on the market.  It not only can be used as a single enclosed PSU, but also a multiple outputs PSU if installs the available NID35/65/100 series DC-DC converter module cards into the UMP-400 PCB.  In our planning, UMP-400 as a standard product it just supplies single output rail, either 24 or 48V.  When you need multiple output rails, please contact MEAN WELL. We can provide customized services immediately. Up to 4 rails of output voltage can be provided. The output voltage can fully meet the needs of various machine, equipment and applications that require multiple sets of outputs.
NMP650 and NMP 1K2 are medical graded power supplies. Independent output module slot and ultra wide output voltage range enable users to set and modify output voltage, current, and wattage according to their demands. NMP series is equipped with intelligent control functions, such as voltage and current control, remote power on and off, over-temperature warning, and DC OK signal, providing remote control and monitoring applications. For the performance of temperature control, the fan speed is automatically adjusted through its internal temperature detection function. 1U miniaturized design significantly enlarges the power density. As for certification, NMP meets medical safety regulations (60601-1), and the circuitry design also refers to IT industry regulations 62368-1. Multiple functions and high quality can fully satisfy all industries' demands. With a five-year warranty and quality verification, the NMP family is an intelligent multi-module power supply with high performance and reliability.

Model UMP-400 NMP650 NMP 1K2
Wattage 400W 650W 1200W
Output voltage
24/48 Accompany with NMS-240 modules
Output channels 4 Channels (Max.) 4 Channels (Max.) 6 Channels (Max.)
Key method 1 Single output independently.
2 Add NID modules to form multiple output
Must use together with NMS modules
Heat dissipation Convection cooling Force FAN cooling
Operating temperature -30~70℃ -30~70℃
Warranty 3 yeas 5 years
Table 1. UMP and NMP Comparision

Main reasons that we highly recommend our medical-grade power supplies, UMP-400 and NMP series.

1. Low Earth Leakage Current Requirement Medical equipment usually contains several compartments, a 3D printer for printing, an LCD screen for display and control, sensors to direct the printer head, and heating elements. These peripheral components are operated at different DC voltages that require multiple AC to DC power supplies that often caused the equipment fails to meet the Low Earth Leakage Current (500μA~750μA) requirement set by safety regulations because the Equipment Earth Leakage Current is the total earth leakage current of each AC to DC power supply. Since equipment operators are usually ordinary employees, regulatory compliance sets such low leakage current to minimize hazard to operators. To meet the low leakage current requirement, a multiple outputs AC to DC power supply is widely used because it only consists of one front-end and multiple outputs that can be configured to meet the peripheral components voltage and power requirements.   
Figures 1 and 2 show the leakage current test results of the MEAN WELL NMP 1K2-HHEKC#-01, consisting of four outputs 24V, 12V, 48V, and 5V, and the total leakage current of four power supplies: MSP-600-24, MSP-300-12, MSP-300-48 and MSP-100-5.

The earth leakage current of NMP 1K2-HHEKC#-01 is 234μA at 230Vac, much less than the 856μA total Erath leakage current of the four MSP power supplies. Therefore, the NMP 1K2-HHEKC#-01 leakage current meets the 500μA~750μA leakage current requirement of the consumer electrical equipment.

Figure 1: Leakage current of 138uA under 120Vac
     Leakage current of 234uA under 230Vac

  Figure 2:Leakage current of 476uA under 120Vac
                  Leakage current of 856uA under 230Vac

2. High Accuracy of Output Voltage

Most users hope to choose a " convenient power supply”, the output voltage of each channel can remain perfectly accurate as long as the change of input and output of the selected power supply does not exceed the rated parameter. However, most of the current multi-output power supplies are not satisfactory. Therefore, choosing UMP and NMP series are your best choice.
As shown in Figure 3. One UMP-400-48 is configured with one NID100-15, and one NID100-12, a total of 3 outputs.
From the test data in Table 1 below,  the voltage accuracy of each group can reach within ±0.5%. It meets the voltage accuracy requirements for most electronic equipment. 

Figure 3. UMP-400-48KJ_Voltage test

  Load Output voltage Open circuit voltage Voltage accuracy
48V 1A 48.084V 48.120V 0.08%
15V 2A 15.060V 15.100V 0.26%
12V 3A 12.000V 12.020V 0.16%

Table 2. UMP-400-48KJ_ Test data
As shown in figure 4. UMP-400 has multiple combinations. However, due to the design of NID modules, some notes are needed.
  1. NID modules are designed with a non-isolated buck converter. Input voltage must be greater than the output voltage, leading, NID35/65/100-24 must and only work when pairing with 48V front end.
  2. Only the 4th channel (V4) can be used as a negative output voltage. As shown in figure 5, when NID35/65/100 form as a negative voltage, the input voltage must lower than 30Vdc, therefore, only UMP-400-24 can be used as a negative output voltage. 
Figure 4. Configuration of UMP-400

Figure 5. NID35/65/100 with negative output

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