Preface
In life, we often use the power bank to charge the mobile phone, and the battery pack of the power tool also uses the battery pack for energy storage, through the special discharge converter, the battery pack of the power tool can be used as a power bank, and the mobile phone can be charged in case of emergency to meet the needs of the emergency.
The charging head network got a multi-function discharge converter for DEWALT power tools, which has USB-C and USB-A output ports, and also has an LED light, which can be used as a flashlight at night, which is versatile. The following brings the disassembly of this DEWALT power tool battery multi-function discharge converter, and let's take a look at the internal design and materials.
Dewalt Power Tool Battery Multifunctional Discharge Converter Appearance
The DEWALT battery discharge converter is available in a yellow color scheme, which is the same color as the battery housing.
There is a label on the side of the converter.
标签型号DCB090 A902
Suitable for DEWALT 20V Li-ion batteries
输入电压：14.4-20V
LED lighting: 200 lumens
On the other side, there are USB-C and USB-A ports, of which the USB-C port supports 18W fast charging, and the USB-A port supports 5V2.1A output.
The housing is fastened with Phillips screws.
At the top, there is an LED light switch button.
Close-up of the switch button.
There is an LED light on the side of the converter.
Close-up of LED lights and reflector cups.
At the bottom of the converter is the plug that connects to the battery.
Close-up of the tongue connecting the battery socket.
The length of the converter is approximately 93.6 mm using vernier calipers.
The converter width is about 59.5mm.
The thickness of the converter is about 38.6mm.
The size of the product in the hand is intuitively felt.
In addition, the net weight of the converter was measured to be about 73.6g.
Dewalt power tool battery multi-function discharge converter disassembly
After looking at the appearance of DEWALT's discharge converter, let's disassemble it and take a look at the internal design and materials.
First, unscrew the set screws to disassemble the housing.
Close-up of the light power switch and LED light window.
The battery pack plug and LED light are connected by wire welding.
The battery pack connection wires are soldered to the back of the PCBA module, corresponding to V+ and V- terminals.
The LED lights are connected with soldered wires for L+ and L- terminals.
Solder, remove the battery plug and LED light.
The LEDs are welded with aluminum substrates, and the light cups are fixed with screws.
Close-up of LED lighting.
The front of the PCBA module is at a glance, the step-down circuit and output interface pad of the DC interface are reserved in the upper left corner, the step-down circuit of the USB-C output interface is in the lower left corner, the step-down circuit of the USB-A interface is in the lower right corner, the LED step-down dimming circuit is in the upper right corner, and the MCU is provided for switch control on the left side.
The back corresponds to the heating chip exposed copper and tin to strengthen heat dissipation.
The USB-C port adopts the synchronous step-down converter of the built-in protocol of Yingjixin IP6520, and the buck converter and protocol chip are integrated inside the chip, and the peripheral circuit is very simple, only 7 resistor-capacitance components + 1 inductor are needed to meet the needs of 20W fast charging. It can be used for vehicle charging, fast charging sockets and multi-port chargers, etc., with high conversion efficiency and comprehensive protocol support. IP6520 has passed USB PD3.0 certification with TID number: 3277.
Yingjixin IP6520 data information.
Close-up of the 22μF inductor for the step-down output of the USB-C interface.
The filter capacitor for the USB-C buck circuit is 100μF 35V.
The step-down converter for USB-A port is from Yingjixin, model IP6536, which is a synchronous step-down converter with integrated switch inside, supporting 5V3.1A output, the fixed working frequency of the chip is 150KHz, and it has multiple protection functions such as input overvoltage, input undervoltage, output overcurrent, output undervoltage, and output overvoltage.
Yingjixin IP6536 data information.
According to the dismantling of the charging head network, Yingjixin IP6536 has also been used by GADMEI 100W 2C1A two-way fast charging mobile power supply, EMPIRE 72000mAh portable energy storage power supply, FLYLEAD 45W 3A1C fast charging car charger, Jiletang 45W 3-in-1 wired car charger and other products.
Close-up of the 33μH inductor used for the step-down output of the USB-A interface.
The filter capacitor specification for the USB-A buck circuit is 100μF 35V.
Two 100μF 25V filter capacitors on the top and bottom of the USB-C interface are used for output filtering of the USB-C interface and USB-A interface, respectively.
The LED driver chip is from CR Silicon, model PT4115, which is a 30V input voltage constant current LED driver, supports 1.2A output current, switching frequency of 1MHz, minimalist peripheral components, adopts high side current detection, and has comprehensive protection functions, and adopts SOT89-5 package.
Close-up of 47μH buck inductor.
A standardless MCU is used for power supply control of the whole machine.
The standardless MOS tube is used to control the power supply.
The 7550-1 regulator chip is used to power the MCU.
The power switch button is patch welded.
The 250mΩ chip resistor is used to sample the output current of the battery pack.
The USB-C receptacle is made of black rubber core and is fixed by soldering through holes.
The USB-A receptacle is soldered with a sinking plate via solder.
A list of all dismantling and a family photo.
Summary of the dismantling of the charging head network
This multi-functional discharge converter is suitable for the use of DEWALT power tool batteries, which can be assembled to form a power bank and LED lighting by assembling the power tool battery and discharge converter. The converter has USB-C and USB-A ports, supports 18W fast charging and 10W output, which can meet the emergency charging use of mobile phones.
Through the dismantling of the charging head network, it was learned that this converter has two built-in Yingjixin synchronous step-down charging chips, of which the USB-C interface adopts IP6520 synchronous step-down converter, and the chip integrates step-down converter and protocol functions. The USB-A port uses IP6536 synchronous step-down converter and fixed 5V output. The periphery of the two chips is extremely simple, which effectively simplifies the circuit design.