Medical Grade Modular Power Supply

Author: Willard Wu /Technical Dept.

Translation: Marketing Department of Olfer electronics.
In recent years, the electronics industry has developed rapidly, and the types and functions of electronic products have become more and more diversified, including medical equipment. A medical system can operate with several different voltages and the total power demand also increases. Before, customers could only use products from a few medical device providers. Today's customers have many more choices, and one of the best decisions is to choose MEAN WELL's NMP650/1K2 series or UMP-400 series medical grade modular power supply, both of which have medical certifications and are distributed by Olfer electronics.

The UMP-400 series is a low profile (1U) module power supply. Its flexible and modular design makes it an unmatched type of power supply on the market. It can be used not only as a single output power supply, but also as a multi-output power supply if you install the NID35/65/100 series DC-DC converters available on the UMP-400 PCB.
The UMP-400 series, in its standard format, only supplies 1 output channel, either 24 or 48V. If you need multiple output channels, please contact MEAN WELL, they can provide customized services immediately. Up to 4 channels of output voltage can be provided to meet the needs of various equipment or applications that require multiple outputs.

The NMP650 and NMP 1K2 series are medical grade power supplies with independent output module and ultra-wide output voltage range. It allows users to set and modify the output voltage, current and power according to demand. The NMP series is equipped with intelligent control functions, such as voltage and current control, remote power on/off, overheat warning, and DC-OK signal, providing remote control and monitoring options.

The fan speed is automatically adjusted through its internal temperature sensing function, for temperature control. The miniaturized (1U) design significantly increases power density. Regarding certifications, NMP series comply with medical (60601-1) and industrial (TI 62368-1) safety regulations. Multiple functions and high quality to meet the demands of all industries. With a five-year warranty and quality verification, the NMP family is a multi-module intelligent power supply with high performance and reliability.

Table 1. Comparison of UMP and NMP.

Top reasons why we recommend our medical grade power supplies, UMP-400 and NMP series.

1. Low earth leakage current requirement.

Medical kits usually contain several components, a 3D printer for printing, an LCD screen for display and control, sensors to drive the printer head, and heating elements. These peripheral components operate with different voltages (DC) requiring various power supplies (AC/DC) which often caused the equipment to fail the low earth leakage current (500μA-750μA) requirement set by the standards of safety, because the earth leakage current of the equipment is the total sum of the leakage current of each power supply (AC/DC). Regulatory compliance establishes a low leakage current to minimize the danger of the operators in charge of this equipment. To meet the low leakage current requirement, a multi-output power supply is used because it consists of only one front end and multiple outputs that can be configured to meet the voltage and power requirements of peripheral components.

Figures 1 and 2 show the leakage current test results of the MEAN WELL device NMP 1K2-HHEKC # -01, which consists of four outputs of 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 total earth leakage current of 856μA of the four MSP power supplies. Therefore, the NMP 1K2-HHEKC # -01 leakage current meets the 500μA ~ 750μA leakage current requirement of consumer electrical equipment.

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

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

2. High output voltage accuracy

Most users hope to choose the "most convenient power supply", the output voltage of each channel can remain accurate as long as the input and output change of the selected power supply does not exceed the rated parameter. However, most power supplies with multiple outputs are not satisfactory, so choosing UMP and NMP series is your best choice.
As shown in Figure 3. One UMP-400-48 is configured with one NID100-15 and one NID100-12 with a total of 3 outputs.

From the test data in Table 2, the accuracy of the stress of each group can reach ±0.5%. Meets voltage accuracy requirements for most electronic equipment.

Figure 3. Voltage test of the UMP-400-48KJ

Table 2. UMP-400-48KJ – Test data
As shown in figure 4. UMP-400 series has multiple combinations. However, due to the design of the NID modules, some notes are needed.

1. NID modules are designed with a non-isolated buck converter. The input voltage must be higher than the output voltage, the NID35/65/100-24 must work when paired with the 48V front end.
2. Only channel 4 (V4) can be used as a negative output voltage. As shown in figure 5, when NID35/65/100 is selected as a negative voltage, this input voltage must be less than 30Vdc, therefore only the UMP-400-24 can be used.