With the development of science and technology, the types, quantities and functions of medical electronic equipment are becoming more and more perfect, and these devices are inseparable from the power supply, so the performance of the power supply plays a key role in the performance of the product. Function, these power supplies are divided into AC/DC level power supply and DC/DC level power supply, among which the selection requirements for AC/DC level power supply are very high, this article will talk about some points of view on the selection of AC/DC level power supply , for reference only.

 Since the objects of medical equipment are people, the requirements for 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 power supply plays a key role in the normal operation of equipment. , so in some international standards, medical power supplies and industrial and scientific experiment power supplies are classified as ISM equipment at the same time, but in view of the strict safety requirements of medical equipment, medical power supply design has its own  especially true for supporting devices. In general, the requirements for medical grade AC/DC power supplies are as follows:

First: Security

In terms of safety, it is mainly reflected in: ①The de

sign requires a sufficient safety distance. Generally speaking, the distance between the input and output should be more than 8mm. ②The withstand voltage between input and output must withstand 4000VAC. ③The leakage current requirement of input to output is very small. In general, the leakage current is required to be less than 200uA in the case of a single fault. ④ Grounding continuity (required for CLASS I equipment). This is also very important for medical equipment. The grounding resistance is large, resulting in a potential difference in the ground potential of equipment powered by different power sources, which may be harmful to seriously ill patients, so the grounding continuity must also be strictly tested. The resistance of the touchable metal is less than 0.1 Ohm.

Second: Reliability

Since the objects of medical equipment are people, the reliability requirements for medical equipment are higher. The normal operation of medical equipment 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 the reliability of the power supply more demanding.

Third: environmental protection requirements

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

Fourth: to meet the requirements of electromagnetic radiation

EMI conduction and radiation meet EN55011, and the limit value is the same as EN55022 ITE equipment, but only the EMI report issued by the testing agency approved by MDD (Medical Device Directive) is valid. It is usually required to have a 6dB margin in the design, so that the requirements can be met during mass production, and at the same time, it is easy to pass the medical system test.

Fifth: the ability to resist interference

This is very important to meet the requirements of anti-electromagnetic radiation. A qualified medical power supply should comply with EN60601-1-2, which must cooperate with many technical requirements related to EMC. In particular, medical power supplies and medical AC-DC power supplies must meet IEC61000-4-2 ((static 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).Medical 60601 power supply provides primary insulation barrier, low leakage current and sufficient safety distance, so that the product meets these medical certification power supply standards.