What is the difference between medical switching power supply and ordinary switching power supply? First, because medical products may directly act on the human body, the requirements for insulation and leakage of medical switching power supply are higher, which is the biggest difference between medical power supply and ordinary power supply.At present, the medical switching power supply must meet the safety standard of IEC60601-1: 2005 (the third edition).Second, the medical power supply has higher requirements for electromagnetic radiation and electromagnetic radiation protection (EMC). The power supply itself cannot interfere with the nearby equipment, and the nearby equipment cannot interfere with the power supply itself.After all, it is a device used on the human body. If the electrocardiogram appears clutter due to interference, it is likely to cause the doctor's misjudgment.Third: In fact, the medical power supply is also used in household and hospital. The international standard requires that the household medical equipment must be Class II. Generally speaking, the AC input end is a double-hole, not a three-hole with a grounding wire.Hospitals, on the other hand, use three-hole sockets with grounding.Attention should be paid to this problem in the design and sale of medical power supply.

What is the standard of medical switching power supply?The medical switching power supply mainly has different certification standards. The power supply of medical electronic equipment is different from the power supply and power supply in the application field of other low-cost products. Medical equipment has to abide by much more rules.For the power supply part, the first question to consider is: What are the risks if you choose such a power supply to use in the medical system?The value of medical equipment is very high, and some key tasks need to be completed.If the medical system fails, the consequences are not as simple as missing a game or taking a wrong train.The normal operation of medical equipment is vital, especially the ordinary switching power supply of medical equipment, which should meet the relevant regulations of stability, leakage, EMI-RFI radiation and protection.These standards and related norms constitute a set of strict normative requirements.Power supplies used in these demanding applications are insulated to strict specifications to prevent electric shock to patients and medical personnel.As the production of medical electronics is generally relatively low.Therefore, it is more cost-effective to purchase power supplies directly from Chengliang Company, which already has the corresponding specific design capabilities and testing technology.

What certifications are available for medical power supplies?Certification varies from country to country.

IEC International Electrotechnical Commission

3C certification CCEE is the meaning of CNEEC certification, which is certified by China Electrotechnical Commission.

Differences between CCC and CCEE power supplies:

1) CCC certification includes CCEE, CCIB (China Import and Export Quality Certification) and EMC (Electromagnetic Compatibility Certification), while CCEE does not have EMC (Electromagnetic Compatibility Certification), so the radiation of CCC power supply is less than that of CCEE power supply.

2) Because the CCC power supply contains a PFC circuit, the power factor is higher. In other words, the use of CCC power supply is more power-saving.

The quality of CCC power supply is better than that of CCEE power supply.

FCC: Federal Communications Commission

UL (Underwriters Laboratories) is the most authoritative and non-profit private safety testing organization in the United States.

CSA is the Canadian Standards Association (Canadian Standards Association)

CE certification The use of the CE mark is increasing in goods sold on the market in the European Economic Area (European Union, EFTA countries, except Switzerland)

GS mark The GS mark is a German safety certification mark.

TUV mark TUV mark is the product type approval mark of German parts.

How big is the Y capacitance of medical switching power supply?To meet the leakage current of 300pa, 1 nF is enough, and 2.2 nF is too large.

If it is only to meet the requirement of no electricity, a single 2.2 nF is no problem, but two in parallel is 8.8 nF, and the leakage current is 1ma.

For 1ma leakage current, if your thumb touches the ground wire and your middle finger touches the shell, you may still feel a little.

If you are nervous or not, if you sweat or not, and if you have a personal constitution.

If there is a Y capacitor at both the input and the output, and a Y capacitor is connected across the primary and secondary, this value needs to be slightly smaller

As for the disconnection of PE line, it is not so strict. The human body also has an impedance. As long as you don't touch it in the swimming pool, you can touch the metal shell without connecting the ordinary communication power supply to PE. You can't feel the current.

The customer took apart a medical switching power supply, the United States, and the ceramic valley safety Y capacitor, but the Y capacitor is very small, only 1000pF.

If there is no Y capacitor, EMC is not easy to deal with.

Should have nothing to do with power, mainly caused by leakage current, but small power is no problem, easy to solve.