You have normal no-load voltage and low on-load voltage. The no-load voltage is normal, indicating that your wireless charging transceiver circuit is normal, but the voltage is pulled down after the load, the most likely is that your coil matching is not good, resulting in insufficient power received by the output end, so the charging voltage will be pulled down.
Wireless charger refers to the use of electromagnetic wave induction principle for charging equipment, the principle is similar to a transformer. There is a coil in the sending and receiving end, and the sending end lineThe coil is connected to the wired power supply to generate an electromagnetic signal, and the receiving coil senses the electromagnetic signal at the transmitting end to generate a current to charge the battery.
A receiving/transmitting coil is arranged at both ends of the mobile phone and the wireless charger. The current of the wireless charger generates a magnetic field through the coil at the transmitting end. When the coil at the receiving end of the mobile phone is close to the magnetic field, the current will be generated. Well, it's a bit of a headache to look at this principle.
Wireless charging is related to the receiver. According to the query of relevant public information, wireless charging is the transmitter (charger)The transmitting end converts electrical energy into a magnetic field through the transmitting coil, and the magnetic field of the transmitting coil passes through the receiving coil. According to Faraday's law of electromagnetic induction of basic physics, an electric field will be generated in the receiving coil, and finally the receiving end outputs electrical energy to charge the mobile phone.
Mi Mix 3 wireless charging for the first time the method is as follows: First connect the wireless charger to the power supply; Just put the phone on and charge it. Mi Mix 3Is millet's MIX series of the third generation full screen mobile phone, the use of sliding full screen design, positioning business flagship. On October 25, 2018, Millet held a new product conference in the Palace Museum to officially launch the new flagship of Millet MIX3.
Mi Mix 3 wireless charging method is to plug in the wireless charger interface, and then put the phone on the charger. Millet MIX 3 appearance, the front is almost all screen, 39 inch AMOLED screen, screen proportion reached 94%, the top of the screen frame also hidden the light and distance sensor, the top of the screen frame in the middle positionOpen hole for receiver with air filter.
The wireless charger is connected to the power supply, and the phone can be charged by gently putting it on. The use of Qi wireless charging standard, support two charging modes 5 watts of universal charging and 10 watts, 5 watts of output power respectively for Mi mix3 fast charging.
Some models of Xiaomi mobile phones support wireless charging. Its models include Mi 12/Pro, Mi MIX Mi 11/Pro/Ultra, Mi 10S, Mi 10 Supreme Commemorative Edition, Mi 10/Pro, Mi Phone 9/ Transparent Premium Edition /Pro, Mi Mix 3/2S. through-power
2, the resonant frequency of inductor L1 and capacitor C1 is 1MHz, because the circuit is resonant, so when the receiving coil is not near the transmitting coil, the no-load current is very small. The receiving end also adopts the mode of resonance, which can maximize the transmission efficiency of energy, and the direct current is obtained by the filtered capacitor after the Schottky diode is rectified, and the charging current is above 0.6A. If the coil is made into a barrel shape, the transmission efficiency will be higher.
3, wireless charging coil A6 three 3 coil - inductance 15uH. Inductance basic formula and inductance definition formula: L=μ×Ae*N2/l. Where: L represents the inductance, μ represents the magnetic permeability of the magnetic core, Ae represents the cross-sectional area of the magnetic core, N represents the number of turns of the coil, and lm indicates the magnetic circuit length of the magnetic core. Empirical formula: L= (k*μ0*μs*N2*S) /l. Among them. μ0 is the vacuum permeability =4π*10 (-7).
4, through the two inductors, the energy can be coupled to the transmission, the secondary coil received by the alternating current through the receiving conversion circuit, it is converted into direct current, directly for the battery charging. In addition to electromagnetic induction, capacitive coupling mode is also a common wireless charging methodStyle. In this mode, no inductor is required, but the electric field of the capacitor is used for energy exchange to achieve wireless charging.
5, if the use is vivo mobile phone, wireless charging is also known as inductive charging or non-contact inductive charging, based on the principle of electromagnetic induction, the device that needs to be charged can be charged by contacting the wireless charger after being energized.
6, wireless charging principle: electromagnetic induction. The charging base and the mobile phone terminal have built-in coils respectively. When the two are close, the coil generates a certain current in the mobile phone receiving coil through electromagnetic induction based on a certain frequency of alternating current, so as to point energyThe amount is transferred from the originating end to the receiving end, and it begins to power the phone from the charging seat. Magnetic resonance.