# Sixth Lichuang Electric Competition# Heap power amplifier

1. Introduction to project functions

Test your house-building skills and find out whether the water depth of the amplifier is deep

Amplifier section

The dual-channel Class D power amplifier based on NS4225 ( C219011) can provide audio input through the 3.5mm headphone jack or Bluetooth on the upper panel (voice control panel), and has a volume adjustment knob.

Design input voltage: 12V, DC5.5 interface/binding post

Design output power: 17W×2 (4Ω load/VCC=12V/THD+N=10%/BTL mode)

Bluetooth part

Bluetooth: I copied the MH-18, but it was still a little noisy, so it failed and I chose external power supply.

Level indicator part

The classic LM3915-N1, with it, you can have fun.

2. Project attributes

An amplifier that just works.

3. Open source agreement

GPL 3.0

GPL 3.0 is used by default, so I use GPL 3.0, hehe

4. Hardware part

Clear treble, accurate midrange, strong bass, layered sound, close sound

I haven't even considered it in this project , as long as it works.

Tell us about your choice?

Preamplifier

I can understand the sample project I copied. Ask me why, try not to ask, because I don’t know either.

amplifier

Based on the starting point of almost getting it, I chose the NS4225, a cheap and good-looking power amplifier chip with relatively simple peripheral circuits and homework.

Bluetooth

There’s not much to say, as long as it can ring, it’s better if it can be operated, and it can’t be pulled down if it can’t be operated.

You are making a lot of money. Can you tell us about your layout?

I asked the boss about the audio line. The boss said that the land can be reserved, so I will do so.

Amplifier output stage, copy homework.

Due to stacking, Bluetooth inevitably introduces contact noise w

5. Software part

Touched

6. BOM list

It’s my favorite time to stack!

There is a slight discrepancy between the actual BOM and the generated BOM. The following pictures and attachments shall prevail.

7. Contest LOGO verification

Woo hoo hoo, can I not participate? I won’t be embarrassed.

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