Apart from the performance of itself, whether medical equipment can work efficiently or not also has the relationship with the power source. The quality of the power source has a direct influence on the stability and reliability of the device. The poor quality even can cause medical accidents and economic loss. The integrated power supplies are used most, which output the different voltage through an integrated converter. The integrated type has so many advantages, such as the low cost, high efficiency, adaptive voltage output, low noise and dynamic response. Some problems must be considered when choosing the power supply plan, such as safety, isolation, compatibility and anti-interference.
Safety and isolation are two main characteristics of the medical power supply, which make it different from the business power supply. Most of the medical equipments are installed near the patient and operator; therefore, their shells are easily to be touched. The problems of the shell will be very dangerous.
The compatibility and anti-interference of the power supply should be considered from many aspects, such as the design, shield, certification, specific application and price. Firstly, the medical power supply must choose the famous brand product which can ensure the quality of design and craft. Secondly, to control the radiation emitted by the power supply, shielding the magnet field is best way. Thirdly, most of the medical equipment should pass the tests of compatibility and anti-inference, such as the FCC-B and CISPR22-B. The devices which have passed the tests have no influence to the other electric components. Fourthly, most of the integrated power supplies have the standard output, although some can adapt the output power by connecting the outside circuit. The adaptive range is small, and the output power is not stable enough. Fifth, the competition on the medical equipment market becomes fierce nowadays, especially the household device. Being the important component of the device, the price of the power supply should be competitive. The related integrated circuit is KA7808.