Safety and isolation of medical power supply
Safety and isolation are also a major difference between commercial power supply and medical power supply, which is related to safety assurances for medical staff and medical personnel who use the device. Although human skin is considered a good insulator, once very small AC currents are applied to the heart, it can lead to heart muscle fibrillation and neuromuscular damage. Therefore, the patient’s environment, equipment, and any part of the patient may be exposed to the current which must be strictly limited to 40-70Hz.
The level of protection required for medical device applications is related to the proximity of the device to the patient. For the medical system, the insulation and protection indicators have three security levels. First of all, all offline power supplies must meet the basic safety requirements of the EN60950 standard. In addition, medical power supply which close to the patients must be in line with the IEC601-1 standard. In addition to the above 2 requirements, also needs an additional barrier to protect the equpiment. Also, when the mains power goes off, it will take a few seconds or minutes for the backup generator to supply power to the hospital. As a result, many medical power sources and devices that use this power are powered by relays from the medical UPS system. The input waveform of the power supply may change and is no longer ideal sine wave. A medical transformer should be added to the front of the power supply to further improve the security level. The equipment directly used for the patient must meet the highest insulation specifications of all of these parameters.
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