Several recommended medical-grade AC/DC power modules

　　With the development of science and technology, the types, quantity and functions of medical electronic equipment are becoming more and more numerous and more and more perfect, and these devices are inseparable from the power supply . Therefore, the performance of the power supply plays a key role in the performance of the product. These power supplies are divided into AC/DC level power supplies and DC/DC level power supplies. Among them, the selection of AC/DC level power supplies has very high requirements. This article will talk about my personal views on the selection of AC/DC level power supplies, which is for reference only.

　　Since medical equipment is used by people, the requirements for the equipment are very high. The normal operation of medical equipment is related to the health and even life of patients and doctors, and the reliability of the power supply plays a key role in the normal operation of the equipment. Therefore, in some international standards, medical power supplies and industrial and scientific experimental power supplies are classified as ISM equipment at the same time. However, given that medical equipment has very strict safety requirements, medical power supply design has its own special specifications, especially for life support equipment with more stringent requirements. In general, the requirements for medical-grade AC/DC power supplies are as follows:

　　1. Security

　　For safety, it is mainly reflected in: ① The design requires sufficient safety distance. Generally speaking, the distance between input and output is more than 8mm. ② The withstand voltage between input and output must withstand 4000VAC. ③ The leakage current requirement of input to output is very small. Under normal circumstances, the leakage current is required to be less than 200uA in a single fault situation. ④ Grounding continuity (this requirement applies to CLASSⅠ equipment). This is also very important for medical equipment. The large grounding resistance causes the ground potential of equipment powered by different power supplies to have a potential difference, which may be harmful to seriously ill patients. Therefore, grounding continuity must also be strictly tested. IEC requires that the resistance of PE to any touchable metal part of the shell is less than 0.1 Ohm.

　　2. Reliability

　　Since medical equipment is used by people, the reliability requirements for medical equipment are higher. Whether medical equipment operates normally is a matter of life and death for patients and doctors, and the power supply is the heart of electronic equipment. Its reliability plays an important role in the reliability of the equipment, which also means that the reliability requirements for the power supply are higher.

　　3. Environmental protection requirements

　　To meet ROHS requirements. Medical equipment is a ROHS exempt product, so power supply products must also meet ROHS requirements.

　　4. To meet the requirements of electromagnetic radiation

　　EMI conduction and radiation meet EN55011, and the limits are the same as EN55022 ITE equipment, but only EMI reports issued by MDD (Medical Device Directive) approved testing agencies are valid. Usually a 6dB margin is required during design to meet the requirements during mass production and to pass the medical system test easily.

　　5. Ability to resist interference

　　This is very important to meet the requirements of electromagnetic radiation protection. Qualified medical power supplies should comply with EN60601-1-2, which must be coordinated with many EMC-related technical requirements. In particular, medical power supplies must meet IEC61000-4-2 ((electrostatic protection capability, required to reach 3kV), IEC61000-4-3 (radio frequency radiation protection capability, required to reach 3V/m), IEC61000-4-4 EFT (voltage transient withstand capability, required to reach 1kV), IEC61000-4-5 (mains surge current withstand capability, required to reach 1kV and 2kV), IEC61000-3-2 (mains line harmonic requirements) and IEC61000-3-3 (power line flicker requirements).

　　6. What is the reputation of the supplier?

　　The U.S. Food and Drug Administration (FDA) requires that medical products must be produced by factories that have obtained GMP qualifications (i.e., factories with good manufacturing practices). Therefore, a qualified power supply manufacturer needs to have good process specifications and quality control.

　　From the above, we can see that the selection of medical power supplies should be cautious, and we should not blindly pursue price. We should ask ourselves whether the system equipped with such power supplies is safe and reliable. When selecting and purchasing medical power supplies, we need to consider various possible risks. We must purchase from reputable manufacturers who can provide certification documents that meet relevant standards and comply with quality and reliability standards and requirements.

　　At the end of this article, we recommend several medical power modules - LD series power modules, LD05 series, and LD10 series from Jinshengyang. Jinshengyang is committed to the development of low-power medical power modules to provide customers with cost-effective products. Currently, it has LD05 and LD10 series medical-grade power supplies, which have the following features:

　　1. Small size and high power density. The LD series power supplies of Jinshengyang are very small. Among them: LD05 series power supplies have an output rated power of 5W, universal voltage input, and a volume of 50.08*25.4*15.16mm. LD10 series power supplies have an output rated power of 10W, universal voltage input, and a volume of 53*28*19mm. This small power supply saves a lot of component space for small medical equipment and makes it possible to miniaturize the equipment.

Figure 1

　　2. High reliability

　　This series of power supplies are designed as industrial-grade products, with an operating temperature of -25-70 degrees, modular design, internal use of thermal conductive potting glue, and international standard pins. The industrial-grade product design provides a guarantee for the reliability of the product, and the standardized pin package reduces the potential single supply risk for customers.

　　3. Security

　　This series of products are designed according to the requirements of medical power supply. ① The power supply is CLASSⅡ equipment. ② In terms of safety design, the distance between input and output is more than 8mm. ③ The withstand voltage between input and output reaches 4000VAC/1min. ④ The leakage current from input to output is also very small. Among them, the LD05 series has no internal safety capacitor design, making the leakage current almost zero, and the LD10 series is only less than 100uA. ⑤ The LD05 series power supply has passed the medical certification of EN60601 and the safety certification of UL60950, and the certification of the LD10 series is in progress (certification standards: EN60601, UL60950).

　　4. Environmental requirements

　　All products are designed according to ROHS requirements. The company actively adapts to the global environmental protection development trend and fully implements "lead-free" production. All products meet the requirements of ROHS testing. The company implements environmental management and control in accordance with ISO14000 standards to ensure the physical and mental health of employees, minimize pollution emissions, fully protect the natural ecological environment, and fulfill environmental protection responsibilities.

　　5. Has lower EMI performance

　　EN55011 has two levels, level B and level A. Level B is much more stringent than level A. Figures 2 and 3 are the EMI test data of the LD10 product. The data show that this series of power supplies has low electromagnetic radiation performance and meets the requirements of EN55011, level B.

Figure 2

Figure 3

　　6. High anti-interference ability

　　Meet the following requirements:

• 　　Electrostatic Discharge            
• 　　RF radiation immunity
• 　　Electrical Fast Transient Burst       
• 　　Surge IEC/EN 61000-4-2 level 4 8kV/15kV
• 　　IEC/EN 61000-4-3
• 　　IEC/EN 61000-4-4 level 3 2kV     
• 　　IEC/EN 61000-4-5 level 4 2kV/4kV

　　7. Complete process specifications and quality control

　　Product quality is the foundation of enterprise development, and the production line is the lifeline of the enterprise. The company takes customer satisfaction as the center, takes the ISO9000 quality management system as the code of conduct, always pays attention to quality control, and quality awareness is deeply rooted in every link and runs through the daily work of every employee. Jinshengyang has passed ISO9001:2000 quality system certification, ISO14001 environmental management system certification, and its series of products have passed UL certification, CE certification and SGS testing. At the same time, it has passed the appraisal of Guangdong Quality and Technical Supervision Bureau and established its own product enterprise standards.

　　Through appreciation of the products, analysis of the design ideas, production processes, quality control, and investigation of the company's strength and reputation, we have concluded that the LD series power supply from Goldensun is a good type of medical-grade AC/DC low-power power supply module and is a reliable power supply worthy of our use.