[DIY] Transform Mobile Phone Battery Charger

The mobile phone battery charger is an abbreviation for the seat charger, which means that the battery board is placed on the top for charging, which is very convenient to use.

The charger is primarily a charger designed for one or one type of mobile phone battery. Therefore, the charging effect of the bracket is better, and the battery life is longer than the life of the universal charging. However, with the rapid development of mobile phones, battery chargers have slowly disappeared. If the mobile phone holder at hand is not as simple as discarding it to the USB output of the battery charger, it is a necessary charging device for the case where the lithium battery needs to be separately charged.

1, battery holder charging 1

2, USB female seat 1

3, clips, etc.

USB connector

USB cable

The contact output mode of the battery holder is changed to the USB interface output mode, which is very convenient for charging the battery after being taken out from the USB.

This battery charger is equipped with a USB power output. The power plug is damaged and replaced with a cable plug. Remove the bottom of the screw with 4 screws and take the case. Open the lid to see the internal structure and component distribution:

From the top layer, you can see capacitors such as rectifiers, switches, optocouplers, and high-frequency transformers USB female:

On the side, you can also see the inline LED charging indicator, and the internal PCB board fixing screws show signs of corrosion:

Remove the screws and look at the bottom PCB trace. This charger features a single-sided printed circuit board design with chip resistors and capacitors on the bottom:

The principle of this mobile phone charger is similar. Let's take a web picture to explain how it works:

Analyze and analyze from the above principles. 220V AC input, one end through 4007 half-wave rectification, the other end through 10 ohm protection resistor, filtered by 10uF capacitor. 13003 is a switching tube for controlling the on and off between the primary winding and the power source to generate an induced voltage in the secondary winding. The sampling coil and the subsequent sampling feedback circuit are mainly used to stably control the output voltage within a required voltage range to ensure the stability of the output. The secondary winding on the right side is rectified by diode RF93 and filtered by a 220uF capacitor to output a voltage of 6V. As can be seen from the analysis of the decomposed circuit components, the disassembled mobile phone battery charger has two sets of secondary output windings, one of which is the output of the battery charging and the other of which is the output of the USB power supply. The use of bridge rectification and optocoupler isolation with feedback is slightly different from the above schematic, but the overall working principle is similar.

This modification mainly uses a USB female socket to replace the original battery charging output terminal and becomes two USB outputs, but the functions of the two interfaces are different. One is for 3.7V battery charging and the other is for 5V power. The device is powered by a power source.

1. After opening the case, open a hole in the open position for mounting and securing the USB socket:

2. After adjusting the position, install:

3, the side position effect is also very good, the hole size is very suitable:

4. Connect the output terminals of the two positive and negative terminals to the USB bus:

5. Fix the USB socket with hot melt adhesive, and finally close the cover to complete:

Two USB output connectors, one for 5.2V and the other for 4.2V:

To prevent confusion of the USB output voltage, both outputs are labeled with a rated voltage:

After this DIY production, the USB charger of the mobile phone that is almost eliminated can be recovered. When you use a separate battery for charging, you can simply charge the battery by connecting the charging output to the battery with a USB cable. it is. End