USB interface charger do not arbitrarily mix

Cell phone charger (power adapter) output interface most of the USB type, different brands, different models of cell phone chargers, although the output voltage is 5V, and the output current is different, these different output current charger can be used randomly interchangeable?

To clarify this issue, we must first understand how the current is controlled when charging a cell phone. After inquiries on the Internet and consulting cell phone manufacturers and power adapter manufacturers, the conclusion is that it is best not to mix at will.

1. The size of the current when the phone is charging, the charging process on the display screen and full of charging termination, is controlled by the internal circuitry of the phone;

2. The output current marked on the nameplate of the power adapter is a reference value, and it is best to use it in a state equal to or less than this current value;

3. Desktop power adapters are not constant current sources based on the labeled output current.

After the manufacturer of power adapter determines the output current of a certain product, in the circuit design and component selection, the circuit and components should be adapted and matched with the determined output current, for example, the specification and size of the high-frequency transformer core, the thickness of the wire diameter of the winding conductor, the selection of rectification mode and component specifications, and the capacity and size of the filtering capacitor are all based on the value of the calibrated output current after a meticulous choice Therefore, it is possible to generate a power adapter with an output voltage of 5V and a labeled output current. As a power supply, no matter how perfect the design, it always has to have internal resistance, like factories and enterprises and rural areas use a large number of distribution transformers, its rated voltage is lOkV/0.4kV, that is, its secondary no-load rated voltage of 400V, and motors and other electrical equipment rated voltage is 380V, here is the use of the transformer's power supply and the resistance of the power transmission conductor on the voltage drop that may occur. The internal resistance of the power supply of the transformer and the voltage drop that may occur on the transmission line are utilized here, so that the voltage between the power supply and the load can be basically matched.

Based on the above analysis, when the calibrated output current of the charger (power adapter) is greater than the current required for charging the cell phone, the charger can easily complete the charging under the control of the power management module inside the cell phone until the battery is full and the power management module issues a charge termination command.
When the calibrated output current of the charger (power adapter) is less than the current required for charging the cellular phone, the control instructions issued by the internal power management module of the cellular phone and the internal resistance of the power supply of the charger are jointly determined, and if it is less than the optimal charging current and greater than the calibrated output current of the charger, the output voltage of the charger at this time will be slightly reduced, and the heat generation will be slightly increased, but the charging of the cellular phone can be completed in a few hours usually, and it will not result in damage to the charger yet. However, cell phone charging can usually be completed in a few hours, not to cause damage to the charger, but the charging time may be extended. Therefore, I believe that the best solution is to use the original charger to charge the phone, or choose a power adapter with a calibrated output current equal to or greater than the current value required for charging; it is best not to use a charger with a calibrated output current less than the phone's charging current to charge the phone.

EAHUNT accepts product customization and printing LOGO, please contact our customer service for details!

product-600-426