Whether a medical device can exert its maximum effectiveness in a hospital is not only directly related to the technical performance of the machine itself, but also has an extremely important relationship with the quality of the power supply. The quality of the power supply will directly affect the operational stability and reliability of medical equipment, and even lead to major medical equipment accidents and huge economic losses.

At present, most domestic medical equipment uses 220V mains power supply. Due to the power supply requirements of various types of medical equipment, the centralized power supply structure is currently the most used. That is, a centralized power converter generates the required output voltages of various voltage levels. Because of its low cost, high efficiency, adjustable output voltage, low output noise, and fast dynamic response, it is very suitable for medical equipment and is currently the most used power supply method for medical equipment. The following questions need to be considered when determining the power supply scheme of medical equipment.

Security and isolation

Safety and isolation is a major difference between ordinary commercial power supplies and medical power supplies. Generally, except for some experimental and analytical instruments, most of the medical equipment is installed near the hospital bed or operating table, which is relatively close to the person and the operator, and the shell is often touched. There are various strong and weak electrical components inside medical equipment. If there is a problem with the isolation between strong and weak electrical or the insulation of the shell material, it will be very dangerous. In terms of safety testing, general medical equipment power supplies must obtain safety certifications such as UL60601-1, C-UL, and EN60601-1. The input and output terminals must have an isolation voltage of more than 4,000V, and require low leakage current to the ground, and meet the requirements of safety creepage distance. For the strong current part, double insulation is required, especially the part that may be in contact with the equipment shell should be reinforced with insulation design.

Electromagnetic compatibility

To choose or build a good power supply system for medical equipment, attention must be paid to improving the electromagnetic compatibility and anti-electromagnetic interference capability of the power supply. Mainly to consider from the following aspects:

design. The design and layout of PCB, the general power supply will contain some high-frequency signals, any printed line on the PCB can act as an antenna, the length and width of the printed line will affect its impedance and inductance, thereby affecting the frequency In response, the printed line that passes the DC signal in time will also couple to the radio frequency signal from the adjacent printed line and cause circuit problems. Therefore, medical power supplies must choose products from big brands and companies with strong R&D capabilities. These products can guarantee good quality in terms of design and production technology.

shield. In order to suppress the radiation generated by the switching power supply and eliminate the influence of electromagnetic interference on other electronic equipment in the medical equipment, the best way is to shield the magnetic field of the power supply, and then connect the entire shielding cover to the housing or ground of the medical equipment. This is a way to do more with less.

Certification. At this stage, general medical equipment power supplies need to pass FCC-B, CISPR22-B, EN55011550226120461000 and other electromagnetic compatibility and anti-electromagnetic interference capabilities. The products selected to complete these tests can not only ensure that there is no electromagnetic influence on other electronic components in the equipment, but also can reduce the research and development cycle of medical equipment and the inspection time before launching to the market.

Size and high power density. At present, in addition to the development of multi-function, high detection and adjustment accuracy, medical equipment is also a development direction that is smaller in size and easy to carry. This requires that the medical equipment power supply must have a higher power output under the condition of a smaller board area.

Special application. At present, most of the centralized power supply products on the market have standard output. Even if some of the power supply products can adjust the output through an external circuit, the adjustment range is not large, and there are problems with stability. If you encounter a low voltage, high current or extremely high DC voltage, how to deal with it, of course, you can use a customized method, but the price is quite high, whether the customer can accept it.

price. Nowadays, due to fierce competition, the price of medical equipment has gradually become transparent. In particular, the prices of small household medical equipment have become very popular and popular. So this requires the power supply, an important part of medical equipment, to have a competitive price.