Shaoxing Yigao square is in center of the city. There are too many crowd people there especially in weekend. But the developers are worrying about that the advertisement may miss the goldtime and customers may be not willing to pay the advertisement fee if one of power supplies are broken. Our company(Youyi Electronics) provide the solution that using the equalize current and backup system power supplies. Every two power supplies comply a group. Each one output half the current that the device need. And if one of power supplies are broken, the other one will supplement the current. So the whole system will not stop working. And LED display will be always playing the video of advertisement. Besides, the signal will be sent to control card when some of power supplies are broken. So that the person who take care of this system can change and repair the power supply in time.