# Sixth Lichuang Electric Competition# Two-in-one mini amplifier

 1. Introduction to project functions

Two-in-one mini amplifier, powered by PD or DC port 12V-24V.
Integrated Class D power amplifier and headphone amplifier, digital volume and equalizer control.
Two-way audio input selection, headphone output, and power amplifier output selection.

Use HK32F030M, PT7313, TPA6138, TPA3116.

2. Project attributes

First published, original.

3. Open source agreement

GPL 3.0

4. Hardware part

The PCB is made of 4-layer boards, with the smallest possible size, minimal interference, and low noise.

The casing is made of aluminum profile, and the front and rear panels are made of PCB boards.

For heat dissipation, thermally conductive silicone sheets are used to fill the bottom surface of the PCB and the aluminum shell for heat dissipation.

 1) Power input, the power supply is 12V-24V, you can also use PD, or QC adapter for power supply, CH224K PD will trick to 20V, you can also use 12V QC adapter.

2) Use PMOS as the power switch of the power amplifier and headphone amplifier, controlled by the microcontroller.

3) Use HK32F030MF4P6, low cost, small size, single chip microcomputer. OLED display screen (SSD1306), pulsator switch facilitates display control.

     The input voltage and temperature were collected at the same time. (Under voltage protection, overheating protection).

     SW1 is a soft switch, controlled by a microcontroller, which facilitates control of the back-end power supply.

3) PT7313 uses I2C to communicate with MCU.

      You can control the selection of audio input channels (two input channels are used here), and the two audio outputs go all the way to the headphone amplifier and all the way to the power amplifier.

      At the same time, the MCU controls volume, treble, bass, balance and gain through PT7313.

4) The headphone amplifier uses TPA6138, R56, R57, R60, R61 to control gain, low distortion, and eliminates the need for output capacitors.

5) The power amplifier adopts Class D power amplifier, TPA3116 or TAP3118. High efficiency, high power, small size, low heat generation.

5. Software part

 AMP-1.0.zip is the latest source code, compiled using MDK5.

Others are historical versions.

6. BOM list

7. Contest LOGO verification

 8. Demonstrate your project and record it as a video for uploading