Brief Introduction

Many project designs have majored in the automation of systems as most people want to do away with constant human interactions with systems. This has therefore prompted the use of microcontrollers in such projects. An example of a commonly used microcontroller is the STM32 microcontroller.

In this project, we are going to see how an STM32 microcontroller chip can be integrated with a USB connector and a Buck converter for power regulation.

Components Used

C1, C3 12p     Device: Capacitor _Small

C2      4uF     Device: Capacitor _Small

C4, C7, C9, C10, C11 100n   Device: Capacitor _Small

C5, C12, C14 10u     Device: Capacitor _Small

C6, C8 2u2     Device: Capacitor _Small

C13, C15        1u       Device: Capacitor _Small

D1      B5819W         Device: Diode _Schottky

D2      BLUE Device: Power LED

D3      B5819W         Device: Diode _Schottky

D4      LED   Device: Status LED

F1       250mA           Device: Poly-fuse _Small

FB1    600MHz         Device: Ferrite-Bead _Small

H1, H2, H3, H4          Mounting Hole _Pad  Mechanical : Mounting-Hole _Pad

J1       Screw_Terminal_01x02           Connector:Screw_Terminal_01x02

J2       USB _B _Micro         Connector: USB _B _Micro

J3, J5  Conn_01x04  Connector_Generic:Conn_01x04

J4       Conn_02x05_Odd_Even           Connector_Generic:Conn_02x05_Odd_Even

L1       10u     Device: Inductor

L2       10u     Inductor

Q1      AO3401A       Transistor_FET:AO3401A

R1, R3 2k2     Device: Resistor _Small

R2      10K    Device: Resistor

R4      47       Device: Resistor

R5      1K5    Device: Resistor

R6, R8 100K  Device: Resistor

R7      68K    Device: Resistor

R9      15k     Device: Resistor

R10    270     Device: Resistor

R11, R12, R13           22       Device: Resistor

R14    1K      Device: Resistor

SW1   SW_SPDT     Switch: SW_SPDT

U1      AP131-35       Regulator_Linear:AP131-35

U2      STM32F405RGT6           MCU_ST_STM32F4:STM32F405RGT6

U3      USBLC6-2SC6          Power_Protection:USBLC6-2SC6

Y1      16MHz           Device:Crystal_GND24

Circuit Diagram and How it Works

The system is designed around an STM 32F406RGT6 microchip with an external 16MHz crystal oscillator and two decoupling capacitors. The system has a BOOT0 switch connected to the N_RESET pin of the STM32 microchip. It is by default high and pulled low during the boot loading process.

A USB connector is provided to the system to load data and also can act as a means of powering the STM 32 Test Board. The test board also has I2C and UART connector provisions.

The board also has two LEDs, one used to indicate power and the other used as a status LED for the STM32.

For the power supply, the input voltage is 12v which is converted by the buck converter circuit to a usable 3.3v. The USB connection can be used to provide the system with 5v and has to pass through the converter circuit. To identify the pin out of the STM32 microchip, you can use cube IDE.

 PCB layout

The design of this PCB was done by KiCAD EDA due to the accuracy required in part placement and routing in preparation for the production/ manufacturing process. The PCB of the test board is a 4- layer PCB with two power planes in the middle layers, and the top and bottom layers being useful with signals.

The 3-dimensional render image of the microcontroller is shown below.

To Order for Such Board

Go to the PCBway instant quote page and fill in the relevant design parameters as shown below.

After filling in the information, press calculates t end up with the provisional cost of the product as shown in the image below.

Press save to cart and the next page pop-up requires you to upload the project Gerber files as shown below.

Add Gerber files then click submit to order. You will get a message order successful.

Our team of engineers will check on your project to ascertain that everything submitted is up to standards and guide you accordingly. Then they will give you a final quote for the project.

Pay for your order through online payment platforms provided by PCBway then sit back and wait for your project to be submitted within the next week.