The radiation of the wireless charger is calculated by taking a lithium battery with a capacity of 1000mAh as an example. 50% charging capacity is about 1.7~1.8Wh. If it is required to be fully charged in about two hours, the maximum charging power must be at least 1W (the maximum power of a GSM900 mobile phone is about 2W). Since the wireless charging method of mobile phones is to place the mobile phone above the charger instead of inside, the radiation leakage rate may not be small.

At present, some special mobile phones can be charged with wireless chargers, but according to the current technology, the charging efficiency is not comparable to that of wired chargers, and the technology of many wireless chargers is immature, and charging the mobile phone will make the mobile phone abnormal. fever.

Is the radiation value of wireless chargers really greater than that of mobile phones? The staff at Dajiaoting Store, a business hall of Beijing Telecom, tested this. The staff took out a high-sensitivity radiation tester. The instrument can measure the radiation value of mobile phones and other items, and can also sense the degree of electromagnetic pollution in the surrounding environment. The higher the value, the more serious the radiation.

The wireless charger is connected to the power supply, and the instrument test window is placed. The value increases to 150 to 180. The increment is not obvious, but it proves that there is radiation.

The next test is the mobile phone. I made a call with the Samsung mobile phone i579 of the staff in the business hall. The radiation value reached 427 at the moment of connection, and it was about 200 after connection. Then I placed the Sharp SH8010C in the test window to make a call, and the value soared to 2000 at the moment of connection. The value floats around 1000.

According to the “Electromagnetic Radiation Protection Regulations”, the average specific absorption rate (SAR) of the whole body for any 6 minutes in a day and 24 hours for ordinary users should be less than 0.02W/kg. But at present, there is no standard specifically for wireless charging.

He Guili, the director of the Tel Laboratory of the Telecommunications Research Institute of the Ministry of Industry and Information Technology, said that it is inevitable that the wireless charger will emit radiation, but since it has been listed, it means that it must meet international standards and will not cause harm to the human body. “As long as the wireless charger is done in accordance with the technical specifications, it will not have radiation hazards to the human body.” He Guili said.

It can be seen that the rumors on the Internet are not true. Nowadays, people are more and more concerned about their own health, so they are also paying more and more attention to the radiation problem of electronic equipment. The wireless charging technology is realized by the principle of electromagnetic induction. Although it will also generate radiation, it will not cause harm to the human body.

Yes, but very little, similar to WiFi and Bluetooth.

Which brand of wireless charger is good

1. NetEase Smart Manufacturing

Over-temperature protection, over-voltage protection, short-circuit protection, foreign object detection, these safety functions are fully equipped. The base and body have anti-skid facilities, and the Qi protocol supports wireless charging of all models. NetEase’s breathing light is a flashing green halo, which is cool. At the same time, there is a certain reminder function, when charging, the slow breathing light. If something is placed on it and it is not charged, it is a rapid breathing light.

2. Xiaomi

The appearance of the charger is a black frosted plastic material, which is simple and beautiful. At the same time, the frosting also gives the mobile phone greater friction. The base is also a full circle of anti-slip rings, which is very slip-resistant. Double charging coils, the recognizable range is very large, and the vertical percentage can be charged. Horizontally, the center is offset a lot, and it can also be charged. Foreign object detection, overvoltage protection, these basic functions are also available.

3. Xiaomi wireless power bank

As a power bank, the capacity is 10,000 mAh, and both wired and wireless outputs support up to 30W. Input 18W, support a variety of fast charging protocols, can fast charge most devices by wired, wireless charging supports all devices, and Xiaomi devices support wireless fast charging. As a wireless charger, the charging protocol is universal and can be charged. Xiaomi’s mobile phone supports wireless fast charging. If you need both wireless charging and a power bank, you can choose this.

4. Netease strictly selected

This creative product from NetEase is essentially a mobile phone stand, but it has a wireless charging function. Height can be extended and lowered, front and rear can be adjusted. But this one does not support the 12 Pro Max, and the rest of the iPhones that can be charged wirelessly do. Available in black and white. This price is not high to choose.

5. PhoneMust

PhoneMust is a professional manufacturer of mobile phone wireless car chargers, wireless chargers with more than 18 years of experience, we are top leader of professional Wireless Charger manufacturers with well-equipped testing equipment and strong technical force.

The wireless charger list

1. Huawei

A world-renowned brand of mobile phones, smart devices, and communication equipment, Huawei is also the world’s leading provider of ICT (information and communication) infrastructure and smart terminals. A smart world where everything is connected.

2. Millet

Xiaomi was established in China in 2010, and its products cover mobile phones, home appliances, and smart terminals. “Let everyone enjoy the fun of technology” is Xiaomi’s vision. Xiaomi uses the Internet development model to develop products, uses the geek spirit to make products, and uses the Internet model to eliminate intermediate links. It is committed to allowing everyone in the world to enjoy high-quality technology products from China.

3. Samsung

Founded in 1938, Samsung is the largest multinational company in South Korea and one of the world’s top 500 companies. It involves many industries, including electronics, aviation, automobiles, finance, machinery, and chemistry. Currently, Samsung has 429 locations in 68 countries around the world and employs more than 230,000 people.

4. Momis

A well-known domestic protective cover brand and a well-known 3C accessories brand in China. Founded in 1999, it is affiliated to Momishi Technology Co., Ltd., a Hong Kong brand focusing on fashionable mobile phone peripheral products, a famous brand of mobile technology products in Hong Kong and Macao, the most dynamic and dazzling mobile phone. One of the digital product accessories brands, the winner of the German Red Dot Award.

5. PhoneMust

Shenzhen PhoneMust Technology Co., Ltd. is a high-tech company dedicated to the development of high-end smartphones, smartphone peripherals, and smart applications. The company was established in Shenzhen, Guangdong in May 2010. It has a mature software and hardware development team and rich experience in mobile Internet products.

1: The principle of wireless charging of mobile phones

The principle of wireless charging of mobile phones is realized through electromagnetic fields. The basic principle of wireless charging of mobile phones is to place one magnet on the bottom of the phone and another magnet on the bottom of the charger. When the two magnets interact, a magnetic field is created that charges the phone’s battery.

2: The method of wireless charging of mobile phone

1. Insert the phone wireless charger into the phone jack. 2. Turn on the wireless charging function of the mobile phone. 3. Hold the phone close to the wireless charger. 4. Wait for the wireless charging to complete.

3: How to choose a mobile phone wireless charger

When purchasing a mobile phone wireless charger, you should pay attention to the following points: 1. First, determine whether your mobile phone supports wireless charging. At present, most mobile phones on the market already support wireless charging, but there are also some mobile phones that do not support wireless charging, so you must first determine your mobile phone model when purchasing. 2. Second, pay attention to the output power of the wireless charger. Generally speaking, the greater the output power, the higher the charging efficiency, but the time required for charging will also increase accordingly. Therefore, when purchasing, you should choose the appropriate output power according to your actual situation. 3. In addition, when purchasing a wireless charger, pay attention to the charging standard it uses. At present, there are two popular charging standards on the market, one is the QI standard and the other is the PMA standard. Generally speaking, QI standard chargers are more compatible, while PMA standard chargers have higher output power.

4: How to use a mobile phone wireless charger

The following points should be paid attention to when using the mobile phone wireless charger to charge: 1. First, insert the mobile phone wireless charger into the charging port at the bottom of the mobile phone; 2. Then, place the mobile phone wireless charger on the bottom of the mobile phone; 3. Finally, turn on the mobile phone wireless charging Function.

With the development of technology, wireless charging of mobile phones has now become a trend. You can find out more wireless chargers here at our website.

So what are the basic principles of wireless chargers on the market? I hope this article can solve some of the confusion of many people who are already in the wireless charging industry or are about to enter the wireless charging industry.

Two tips before reading:

This is not a popular science article and requires some basic knowledge of electronics. If you are a salesperson in this area, you can understand the general logic without seeking to understand the meaning of each noun.

The article is not long, it only looks at the pictures and answers four basic questions:

1. What are the components of wireless charging?

The left side is the TX, which is the transmitter, and the corresponding product is the wireless charging transmitter. On the right is Rx, which is the receiving end, and the corresponding product is a mobile phone with wireless charging function.

TX side: MCU, power full bridge, and LC resonant Tank composed of inductors and capacitors, where the inductor is the transmitter coil.

RX side: MCU, rectifier bridge, LDO, Charger chip, battery, and LC resonant Tank, where the inductance is the receiver coil.

2. What is the power transmission path of wireless charging?

The wireless charging transmitter input DC voltage (DC Voltage). The DC voltage passes through the power full bridge to generate an AC voltage (AC Voltage) at points SW1 and SW2, which is actually a square wave.

A square wave is applied to both ends of the LC Tank to generate an alternating current (AC Current). The alternating current is passed through the coil to generate a magnetic field. The coil at the receiving end induces this magnetic field, and an alternating current (AC Current) is generated at the receiving end of the LC Tank.

The alternating current is converted into a direct current voltage (DC Voltage) through the rectifier bridge. The DC voltage then charges the battery through an LDO and a Charger.

3. What is the control loop of wireless charging?

In order to ensure the stability of the entire wireless charging system, VRECT needs to set a target voltage (Target Voltage) and control it through a feedback loop; for high conversion efficiency, its value is usually set only a little higher than LDO.

The feedback loop will first collect the VRECT voltage and subtract it from the target voltage to generate an error signal (Control Error). The error signal will be transmitted to the MCU of the transmitter through the communication method specified by WPC, and the MCU will determine whether the receiver wants the transmitter to increase or decrease the energy.

The MCU controls the transmitted energy by controlling three signals: input voltage power switching frequency of the full bridge power input duty cycle of the full bridge

4. What is the communication mechanism of wireless charging?

The essence of conveying information is to make the signal change. For example, if I wave to you, if you see my hand changing, you know that I am calling you.

When the receiving end transmits information, it will connect or connect a set of capacitors on both sides of the receiving end LC Tank. The connection or connection of the capacitor will cause the equivalent impedance of the transmitter LC Tank to change.

The change of the equivalent impedance will cause the current in the transmitter LC Tank to change, and the voltage (Coil Voltage) at the connection between the capacitor and the inductor to change. The changed signal will be collected and demodulated, and transmitted to the MCU.

The whole change rule is written in the WPC protocol. The MCU uses the WPC protocol to know what information the receiver has told the transmitter.

Which phones does the wireless charger support?

With the development of the times, the replacement of mobile phones has accelerated, and smart phones have become very smart. Even many brand mobile phones have begun to support wireless charging. For example, some well-known brands such as Apple, Samsung, Xiaomi, and Huawei support wireless charging. To find out whether your mobile phone supports wireless charging, and how much W wireless charging is supported. You can ask the mobile phone manufacturer when you buy a mobile phone, or check it yourself on the official website of the mobile phone.

The benefits of wireless phone charging:

One of the advantages of wireless chargers is to get rid of the shackles of various mobile phone data cables: put the wireless charger on the table, you can put your mobile phone on it to replenish the power in your spare time, and take it with you when you want to use it. to use. In this way, you can use the fragmented time to charge every day, and avoid the trouble of finding wired chargers everywhere.

The second advantage of wireless chargers is to make mobile phone charging more comfortable. Nowadays, mobile phone wireless charging is actually the most suitable charging method for mobile phone lithium batteries. Because the characteristics of the lithium battery itself are suitable for charging and discharging, and the current wireless charging power of mobile phones can reach 30W, which is relatively fast, so the charging speed is not slow, and it will not take too long to fully charge.

1. First of all, you need to ensure that your mobile phone supports wireless charging, because wireless charging requires the hardware support of the built-in wireless induction coil of the mobile phone;

2. Connect the wireless charging board to the data cable to the charger, a general mobile phone charger will do; generally, the charging board will have a light prompt after the power is connected, and then put the mobile phone on the charging board;

3. The position of the wireless coil of different mobile phones is different. Generally, it is near the lens position. You can try to find the position of the wireless charging by drawing a circle. After the charging starts, the mobile phone will light up and display the charging prompt;

4. It should be noted that wireless charging is not a long-distance charging method, and the mobile phone still needs to be charged close to the charging board;

5. Wireless chargers are transmitted by radio waves. Radio waves are not only electromagnetic waves, but they can also transmit energy and penetrate the air, thus making wireless power transmission possible;

6. In the selection of chargers, since most of the current Qi charging mobile phones support up to 10W wireless charging, it is sufficient to have a charging head that supports more than 10W.

2. At present, long-distance charging is not supported, which may be achieved in the future. What is wireless charging technology? According to a report in the United States, a research institute has developed a long-distance wireless charger, which includes a transmitter with a plug and an electronic receiver. As long as the power supply is within a certain range, it can be transmitted to the terminal equipment equipped with the receiver 。

3. The wireless charger uses the radio wave to transmit. The radio wave is not only a kind of electromagnetic wave, but also can transmit energy and penetrate the air, so it makes the transmission of wireless power possible.