The factors deciding whether the design of PCB can be successful

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The factors deciding whether the design of PCB can be successful

Postby liuliying » Thu Feb 21, 2019 3:09 am

Modern Prototype PCB are required to maintain thousands of networks, which may bring much trouble to the wire distribution of key areas in the design. The best way to solve this problem is to divide the network wires into groups so as to create more effective wire distribution. After appropriate grouping and wire distributing, marks can be made and important groups can be screened to exhibit the key network in the distribution.
1. Over current protection: Once the current is too high, the power will be automatically off in case that the current and parts will be damaged for exceeding the rated current.
2. Over voltage protection: It is designed to prevent over voltage or static electricity from damaging the electronic components, which is therefore widely applied in all kinds of electronic products, such as, telephones, fax machines and high-speed transmission access. In particular, it is extremely important to prevent abnormal voltage or static electricity from damaging electronic equipment in terms of its applications in telecommunication facilities.
3. Over temperature protection: It has been over sixty years since the temperature protection components became commercialize. Currently, over temperature components are widely applied in areas which have special requirements for temperature. Based on the actuating principle, these protective components can be categorized into chemical actuation and low-temperature alloy actuation. The chemical actuation products are characterized by complicated structure and high cost and mainly used for low-temperature products while the low-temperature ones operated through a low-temperature fuse wire with long diameters to get through so that the current produced by rated current won’t be fused by the fuse wire which is used to adjust the fusion point according the proportion of tin, bronze, silver, bismuth, etc..
4. Over temperature & over current protection: In recent years, with the improvement of all kinds of applications, mere temperature protection can no longer meet the security demands of the changing electric appliances, electric machines, motor and 3C products. Therefore, components which can provide monitor and in-time protection in response to the abnormal circumstances in temperature, current and voltage are developed, whose largest applications are in lithium-ion battery and lithium-ion polymer battery.
5. Over current & over voltage protection: With modern electronics getting more and more complicated, the requirements for protecting component applications are increasingly enhanced, for example, the protection should be thorough; the headspace should be limited, etc.. With more requirement being raised, a wave of assembling and encapsulating is blowing in the components protection area with over current & over temperature protection mentioned above being one of them. However, currently, most products with over current & over voltage protection are still in the R&D stage with no any mature commercialized products coming into market yet.
Over current protection components are mainly as follows: one-time fuse protector, self-recoverable settable fuse protector, fusing resistance, breaker, etc., among which the most important one is self-recoverable fuse. The following are the main points for PTC self-recoverable fuses as a over-protection component:
1. The current should be slightly higher than that of the normal working voltage.
2. Vmax should be over or equal the maximum working voltage.
3. Imax should be over the fault short-circuit current.
With development of science and technology, electrical components are becoming more diversified and complicated. The applied circuit protection components are no longer the old and simple glass-tube fuse in the past. The common protective components are: voltage dependent resistor, TVS, gas discharge tube, etc., which have developed into a newly-emerging electronic field with various types.

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