Micro-range wireless charger circuit diagram design

微盟ME2188A33PG

Photocoupler

Overview:
1 Introduction Radio technology has been used in communications for nearly a hundred years. From the original radio broadcasts and radiotelegraphs, to the current satellite and microwave communications, and to the mobile communications, wireless networks, GPS, etc. of almost every individual in the world. Wireless communication has dramatically changed people's production and lifestyle. Without wireless communication, the goal of an information society is unthinkable. However, wireless communication transmits weak information rather than power/energy. Therefore, many portable mobile products that are extremely convenient to use are connected to the grid for charging from time to time, and thus have to leave various sockets and connecting cables. This makes it difficult to achieve a waterproof sealing process, and this personalized cable makes it difficult to use chargers for different products. If you completely remove these tails, the mobile terminal device can get real freedom. It is also easy to achieve sealing and waterproofing. This goal must require energy to be transmitted wirelessly like information.

The transmission of energy and the transmission of signals are clearly different. The latter requires the integrity and authenticity of its content, which does not require efficiency, while the former requires power and efficiency. Although the idea of ​​wireless transmission of energy has long existed, it has not been able to break through the bottleneck of efficiency, making it impossible to enter the practical field.

At present, there is still no substantial breakthrough in this bottleneck. However, if the transmission distance is not strictly required (not compared with wireless communication), such as in the range of several cm (referred to herein as macro), the transmission efficiency is easily improved to a satisfactory level. If wireless transmission under macro conditions can be realized with relatively simple devices and commercialized applications can be promoted, mobile electronic devices that are ubiquitous in today's society will likely face a new revolution.

2 Working principle Converts direct current into high frequency alternating current, and then wirelessly feeds the electric energy through mutual inductance coupling between the primary and secondary coils without any wired connection. The basic scheme is shown in Figure 1.

The wireless charger is composed of a power transmission circuit and a power receiving and charging control circuit.

2.1 The power transmission part is shown in Figure 2. There are two kinds of power supply for the wireless energy transmission unit: 220V AC and 24V DC (such as automotive power), which is selected by relay J. According to the principle of AC priority, the normally closed contact of relay J in the figure is connected to DC (battery BT1). S3 is normally on.

Figure 2 Radio energy transmission unit circuit diagram

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