The rapid development of the medical supply of medical devices should be how to choose (1)

1 Introduction

Today's society, with science and technology progresses, more and more modern medical equipment have been booming, especially in contact directly with the human body with electronic devices, in addition to the performance of the instrument itself increasingly high demands from the outside, on human safety considerations are more and more attention.

For example: cardiac puncture monitor, ultrasonic, mother and baby monitors, baby thermal insulation tester, life monitor and other close contacts with the human body, which means that patients use instrument instruments cannot use the instruments and on the human body caused a risk of electric shock or other aspects of any danger.

2 select medical power supplies

Medical electronics, and other positioning in the mass market and care about the cost of consumer electronics and other low-priced products in the field of electronics and power electronics, medical electronics to abide by the rules.

If the designer is responsible for the system power design for system power supply part of the first to consider the question: buy or manufacture for solution. As a general medical electronic output is relatively low, the designer must consider buying or self-made. Medical electronics designers rarely consider their own design offline power supply. Because this kind of special design and test the required investment and ultimately does not match the scale of production, equipment manufacturers will find product production is difficult or impossible to apportion the investment during the design phase. Therefore, to have appropriate professional design and testing technology company in direct purchasing power and more cost-effective.

⑴ price

In the commercial application of design, if the quality guaranteed, it is very easy to shop around to select the price directly after the lowest power products.

This time, the price is the minimum but the "decent" products tend to be a winner, and the best products are not welcome. This is for those who will soon be abandoned or not need maintenance, one-time electronic product is nothing, but if designers pick one such power to use medical system will have any risk? medical e-value is very high, you need to complete some tasks of vitals. If the health care system fails, the consequences of not just missed a game or on the wrong train so simple. The proper functioning of the medical equipments, the remarkable life and death is medical equipment of power supply, must meet safety, leakage, EMI-RFI radiation and the relevant provisions of the terms of protection. These standards and related safety specifications constitute a set of strict regulatory requirements. For such demanding applications in power in insulation measures must comply with the strict specifications in order to prevent electric shock patients and medical staff. EMC is also a crucial issues, including how to reduce electromagnetic radiation and how the two aspects of protection from electromagnetic radiation. Therefore, the design of medical power supply, the preferred must be the product quality and reliability.

Usually designers on the commercial power supply and power supply for medical and confusing for mass market manufacture of various low power of the manufacturers may apply these commercial power does not make the changes as a medical supply sales.

In this regard, the purchaser must be careful, because just for the sake of cheap and select such power products will lead to terrible consequences. Therefore, designers need to understand relevant provisions and regulations.

⑵ GMP accreditation

United States food and Drug Administration (FDA) requirements for medical product must be obtained GMP (that is, with good job specifications) of factory production.

This is in addition to the traditional ISO9000 certification should require manufacturers to produce a quality certification system, to prove its quality control procedures in line with GMP standard. Similarly, China also has medical power of strict control, for example, must conform to CE, UL, and a series of medical certification requirements.

GMP norms requiring manufacturers must have the parts quality control procedures, and related documentation.

Select medical power supply to the manufacturer for parts quality control procedure, the quality of the data and test files, understand what the program does require manufacturers to produce to substantiate its product quality and reliability of file, reputable manufacturers will be pleased to provide. We found that many low-cost manufacturers are using no marks, no manufacturers of power products or counterfeit power product, to the end of medical electronics OEM brings a lot of problems. If the manufacturer cannot take out the authentication file, but they only POS terminal power transformed when medical power sales, then, this product will only make the users to gain. Therefore, a good selection of medical supplies, GMP qualifications can appropriate proof of the production and quality control, but this product is good product? no, we also have on product performance parameters and reliability for master, that is, whether the product has adopted a number of international standard.

EN60950 is applicable to the general power to satisfaction of international safety norms.

Medical power supply also needs to be satisfied with the specification of the minimum basic requirements.

But the medical power of international safety norms are stricter IEC601-1 A2 and press area has three versions: Europe is EN60601-1, UL2601-1 is the United States and Canada is No 601.1 CSA22.2.

These specifications cover electric shock protection, fire and mechanical aspects of the specification and creepage distance and clearance, high-voltage insulation etc test indicators.

Medical supplies must adopt appropriate design technology to ensure that the input when the exception is still stable work, and in some remarkable (such as with an oxygen and/or anesthetic gases) of the environmental conditions. In these applications, the fire is also a key issue.

⑶ leakage current

Leakage current is a protective earthing conductors of electric current to flow.

Without grounding, if a conductive path (such as the human body) exists, the current available from conductive parts or non-conductive parts of the surface to ground. Safety grounding conductor always exist outside current. Typically, a medical power of leakage current limit is one-tenth of the normal power supply.

IEC601 standard all power leakage current indicators than non-strict medical power supplies.

Which the specification defines several different is the most critical of leakage current, E.g. on the floor drain current (flow along the grounding) and shell leakage current (through patient flow from the shell). Standard for the following IEC601, three main types of device power supply maximum leakage current had different definitions:

B class: no physical contact with the patient's device, such as laser treatment instrument;

BF: physical contact with the patient's device, such as ultrasound, various monitor (including EGC devices) and operation;

CF: contact with the patients ' heart of devices, such as cardiac puncture monitor.

People often misunderstand that the device type of leakage current indicators.

In fact, these types of devices promise leakage current are the same. North American index requirements than European EN60601-1 requirements of the promised leakage current tighter. For example, Europe and the United States allowed 0.5mA, and Canada only allow 0.3mA. Thus, medical devices, designers need to focus on their products which will be sold to.