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Reasonable Design Is Critical To The Safety Of The Switching Power Adapter

Shenzhen GEO Technology Co.,Ltd | Updated: Aug 01, 2017

  Reasonable design is critical to the safety of the switching power adapter

  Personally think that the choice of switching power adapter is the first standard of its security, which is the basis. In order to let you on the switching power adapter security performance has a more in-depth understanding, here today to introduce some of the security features can enhance the design skills.

  First, the super power delay shutdown protection

  Ultra-power delay shutdown protection as a very effective output overload protection technology, has been produced in the domestic power adapter products have been widely popular. In a time-delay system, the requirement for a short-time transient current is permissible and the power supply is turned off only when the current stress exceeds a safe value for a long time. The provision of short transients will not compromise the reliability of the power supply and will not have a significant impact on the cost of the power supply. Only long-term continuous current requirements will affect the cost and size of the circuit.

  Second, the pulse by the super-power or over-current limit

  In the switching power supply adapter new product development process, the pulse by the super-power, over-current limit is essential, and this one by one pulse over-power or over-current limit, in practical application is very effective output overload Protection method, this technique is often used in additional secondary current limiting protection. In the previous switching equipment, the input current is to be monitored in real time. If this current exceeds the specified limit current value, the conduction pulse will be terminated. In the continuation of the flyback converter, its maximum current determines the power of the circuit, this type of protection circuit becomes a real power limit protection circuit.

  Third, the flyback super power limit protection law

  In addition to the above two methods introduced, the flyback power protection method is also able to effectively protect the switching power adapter security work important measures, the current adapter in the domestic R & D and manufacturers of the production process is widely used. This protection technology is an extension of the speed form, in the use of the protection of the adapter circuit, there is a special circuit to monitor the primary and secondary voltage, the output voltage decreases to reduce power. In this way, when the load resistance decreases, the output current is reduced to prevent the secondary components from being subjected to excessive stress damage. The disadvantage is that a lock occurs when used for non-linear loads.

  Fourth, constant power limit protection law

  Constant input power limit protection method is today we want to introduce the fourth switching power adapter protection technology, is currently more common at home and abroad an output protection technology, in the notebook adapter and mobile phone adapter in the development process, are ultimately it The figure. The protection principle of this method is to protect the primary circuit by limiting the maximum transmission power. However, in the flyback converter, this technique can hardly protect the secondary output element. For example, in a discontinuous flyback converter, the primary side peak current has been limited, that is, given the limited transmit power.