Health, safety and stability, the use of non-contact wireless charging, air charging has been EMC electromagnetic radiation and other tests, to protect the health of users without radiation.
With the popularity of 5G mobile phones, there are more and more small applications such as wechat, Tiktok, mobile games, etc., and mobile phones have covered lifeEvery corner of life.
At present, there are many people using wired charging, and the price of wireless fast charging is more expensive, and the applicability is not as good as line charging, especially when charging while playing mobile phones, wireless charging is more inconvenient.
In the RE test process of EMC, the peak value, the quasi-peak value, the average value of these three pointsWhat does it all mean? In the RE test process of EMC, these three values respectively represent the meaning of: average detection: its characteristics are the same number of detector charge and discharge, especially suitable for continuous wave measurement. Peak detection: The number of charging intervals even narrow pulses can quickly charge stable values.
First: peak value, quasi-peak value, average value meaning: the difference between the three is mainly concentrated with the difference in charge and discharge time of the detector average detection: its biggest feature is that the charge and discharge time constant of the detector is the same, especially suitable for the measurement of continuous wave.
This is the data of CE conduction test in EMC, passAccording to the regulatory requirements, QP and AVG values must be within the limit value, red represents the QP value limit is the quasi-peak value, blue represents the AVG value is the average value, the conduction of this electronic ballast is too.
A higher curve representing the peak detection, and a lower curve representing the mean detection. Electromagnetic compatibility (EMC) is a comprehensive evaluation of electronic products in the electromagnetic field interference size (EMI) and anti-interference ability (EMS), is one of the most important indicators of product quality, electromagnetic compatibility measurement by the test site and test instruments.
is not particularly familiar with this piece, but since the conductive anti-interference part did not pass, then the solution is nothing more than filtering and grounding. External interference is eliminated by electrostatic shielding (cable wrapped in copper foil or metal mesh, equipment metal seal) or filter, so that interference does not enter the equipmentJust noodles. If the interference is directly added to the power line (not coupled), then it is good to add a suitable filter in the device.
Peel the outer layer (shielding layer) of the coaxial cable to expose the core wire, wind the core wire into a small ring with a diameter of 1 to 2 centimeters (1 to 3 turns), and weld it on the outer layer. A device, the original electromagnetic radiation emission intensity is 300mV/m, plus the shielding box, the radiation emission is reduced to 3mV/m, the shielding efficiency of this box is how much dB? The shielding efficiency of this chassis should be 40dB.
The main solutions of EMC include electromagnetic interference suppression, electromagnetic radiation control and anti-interference ability improvement. Electromagnetic interference suppression: (1) Filtering: By using filters wireless charge emc rectification , electromagnetic interference generated by electronic equipment can be reduced. Filters can be installed on power and signal lines Wireless charge emc rectification to reduce conducted interference. For high-frequency electromagnetic interference wireless charging emc rectification, the appropriate filter can be used. (2) Shielding: Shielding is an effective way to reduce electromagnetic radiation.
First of all, it is necessary to determine whether it is differential mode interference or common mode interference, and then determine the frequency point of interference to suppress, if it is differential mode interference can be added X capacitance, if it is common mode interference can be suppressed by Y capacitance. Reducing the input current may solve the EMC conduction problem, the key is to see whether the current is caused by large, to find out where the core interference is.
Conducted 20MH-30MHz Wireless charging emc rectification ; It is mainly common mode interference, which can be attenuated by the following measures; 1, the shell grounding power supply, can adjust the input of two Y1 ceramic capacitance; 2, the outer layer of the transformer nozzle is covered with copper foil and connected to the primary ground; The innermost layer is shielded with 0.9T copper foil.
One is to study whether the power supply itself is qualified. Second, in the case of qualified power supply, whether the electric part connected to this power supply will produce harassment, resulting in unqualified power supply by conducting. In addition, I would like to know whether the power supply of your vacuum cleaner is built-in or external? Does it have a built-in battery? If it's external, it's usually justTest a charging mode, so that the main problem is the power supply.
You look at some of your circuit grounding is good, or improve the ground point, although some are grounded but away from the source of disturbance will create a large electrical loop in the circuit. Try a bypass filter on the output.
Extension: Open wireless reverse charging method: You can enter the phone Settings -- battery -- more Settings -- open "wireless reverse charging", you can give the peripheral after openingFor up to 10W charging power supply fast charging. Note: After this function is enabled, if there is no charging for other devices for a long time, it will automatically turn off; This function cannot be enabled when the battery life of the phone is less than or equal to 15%.
Open Settings on your phone. Click the "Battery" option. Turn on the Wireless reverse charging switch.
Open the Settings menu of your phone. You can swipe your finger on the home screen to find the "Settings" icon and tap into it. In the Settings menu, find the "Power Management" option and click on it. On the Power Management page, you can view the Wireless Charging optionItem. Click to access this option. In the wireless charging Settings screen, you can see an "Enable wireless charging" switch. Please switch the switch to on.
First, click on [Settings] on the desktop of your phone. Next, under the Settings menu, find and click on [Battery]. Finally, open the switch button on the right side of [wireless reverse charging]. Huawei radio charging only for some mobile phones have this function, not all mobile phones have. Huawei Wireless charging method: Connect the charging head to the charging base using a data cable, and then plug the charging head into the power supply.
However, if there is a small change in the distance between the power supply and the receiving device, the resonance frequency will also change. To solve this problem, the researchers developed a wireless charger that can transmit power even when the distance from the receiving device changes. However, this method is not practical, and the amplifier itself needs to use a lot of power to achieve the amplification effect, resulting in the transmission efficiency of the system is only about 10%.
The wireless charging charger is a small oneTransformer, its role is to convert the household voltage into a mobile phone voltage that can be loaded by the mobile phone battery. When the charger converts the household voltage into the load voltage, the load voltage is reduced, thus reducing the charging efficiency of the charger. By amplifying the power, the power amplifier can not only meet the safety, but also improve the charging efficiency.
The difficulty is that if the distance between the power supply and the receiving device changes slightly, the resonant frequency will also change. To solve this problem, three years ago, researchers developed a wireless charger that can transmit power even when the distance from the receiving device changes. studyThe idea is to use integrated amplifiers and feedback resistors to achieve frequency resonance, which can eliminate the problem of distance.
Wireless charging technology is the use of electromagnetic induction principle, in the sending and receiving end with the corresponding coil to send and receive the induced current to charge.
Get rid of the shackles of data lines and wireless chargers The current wireless charging technology is still in its infancy, compared with the traditional charging method, the mainstream wireless charging only replaces the data line with a wireless charger. Only when the phone is close to the charger, it can be charged normally.
Reduced bandwidth: A high Q value means that the circuit has a narrower passband, which helps maintain signal stability and purity in situations where precise frequency control is required, such as oscillators and clock circuits. Improved efficiency: In power transmission and conversion systems, a high Q value can reduce energy loss because at resonant frequencies, the active resistance component of the circuit is minimal, so the energy conversion efficiency is higher.