Eahunt Chargers 2023

The low-frequency (50Hz) AC is first rectified to DC, and then this DC is switched to a high-frequency (tens of KHz) AC signal using a field-effect tube (equivalent to a rotary switch), which is then transformed by a transformer and then rectified to DC. The purpose of this is to reduce the size of the magnetic components that is the transformer. 220 AC rectification, and then oscillating circuit vibration (most of the self-excited), into tens of kilohertz of high-frequency signals, and then through the isolation of a small high-frequency transformer transformed into a few volts of low-voltage high-frequency, filtering, regulator, and then the output of 5-6 volts DC (according to the cell phone points) to the cell phone charging. Similar to a small switching power supply, compared with the industrial frequency transformer (very heavy kind of iron core transformer) high efficiency and light weight.

Nowadays, cell phone chargers use lithium-ion batteries, talking about this lithium-ion batteries, first of all, a brief introduction, the so-called lithium-ion batteries is the use of lithium-ion can be absorbed, detached from the carbon material as a negative active material battery, lithium-ion symbol for Li-ion. batteries are generally composed of positive electrode, negative electrode, diaphragm, electrolyte, and other basic elements.

Lithium-ion battery charging process is divided into two steps: the first is a constant current charging, its current is constant, the voltage is rising, when the voltage is charged to 4.2V automatically converted to constant voltage charging, constant voltage charging in constant voltage charging, the current is getting smaller and smaller until the charging current is less than the pre-set value so far, so some people use a direct charger to charge the cell phone battery when the battery is obviously power display has been full, but still Display is charging, in fact, this time the voltage has reached 4.2V so the power display is full, then it is in the constant voltage charging process.

Why constant voltage charging it, directly with constant current charging to 4.2V is not on the line, in fact, it is easy to explain, because each battery has a certain internal resistance, when charging with constant current to 4.2V, this 4.2V is not the actual voltage of the battery, but the voltage of the battery plus the battery internal resistance on the consumption of the voltage of the sum of the current is very large, so the consumption of the voltage of the internal resistance on the consumption of a very large, so that is the actual battery voltage, the voltage is the actual voltage of the battery. If the current is very high then the voltage consumed on the internal resistance is also very high, so that is the actual battery voltage may be much smaller than 4.2V, so use the constant voltage charging process to slowly reduce the charging current, so that the actual battery voltage is very close to 4.2V.

When charging a cell phone, the charger first turns 220V AC into high voltage DC through a rectifier circuit, then into high frequency high voltage pulses through a switching tube, and after that into low voltage pulses through a transformer, the exact value of the low voltage depends on the voltage needed by the device being charged. Finally, the low-voltage pulse is rectified and stabilized by the rectifier and voltage regulator circuits to become the corresponding DC power. In other words, the process from 220V AC to 5V DC will mainly go through the rectifier circuit, transformer, voltage regulator circuit and so on, the charger is just changing the form of electrical energy.

If you want to know more about switching power supply information, you can consult Xiamen Eahunt Electronics.

Whatsapp:+86 13860786068

Email: athene-cai@eahunt.com

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