Table of Contents
TPA3126D2 50 + 50-W with Bluetooth + case 3D, stereo, low-idle-current Class-D power amplifier circuit, TDA3126 power amplifier IC, 2 auxiliary input, 1 Bluetooth input + 1 AUX output
Project Overview: It has reverse input function. There are two AUX input channels (one front and one rear) and one Bluetooth input channel. The overall volume and each channel volume can be adjusted. There is an AUX output interface (on the side), and when used with the amplifier, the output circuit will be reduced.
There is another way to use an AUX cable, one end connected to the AUX output and the other end connected to the AUX input, which can provide certain gain to the amplifier, and it has been tested to be effective. The original file of the casing can be exported in the PCB file, and the attachment is the modified file with some silk printing added. Other precautions and instructions are also described in the schematic diagram.
Precautions: The amplifier is a stereo with left and right channels. It is recommended to use two 4Ω50W speakers (as stated in the manual). The amplifier output interface should correspond to the speaker interface.
NL connects to the negative pole of the left channel speaker, PL connects to the positive pole of the left channel speaker, NR connects to the negative pole of the right channel speaker, and PR connects to the positive pole of the right channel speaker.
Currently, a 50K inverter is used, but it is recommended to buy a 10K one, as there may be current attenuation with the 50K inverter, or the amplification factor of the operational amplifier may not be sufficient. You can refer to the calculation formula in the schematic diagram and change the resistance to amplify the current. The demonstration video was not able to find a ready-made 50W speaker at that time, only a 4 Ω 20W one was found, so the audio quality and volume of the test were not good.
Schematic TPA3126D2 power amplifier + AUX + Bluetooth
About ic TPA3126
The TPA3126 is an integrated circuit (IC) that is widely used for audio amplification purposes. It is specifically designed for high-performance audio systems, offering excellent audio quality and high efficiency. The TPA3126 operates on a wide supply voltage range, making it versatile and suitable for various applications. This IC provides a powerful output, making it ideal for audio devices such as home theater systems, soundbars, and portable speakers. Additionally, the TPA3126 features built-in protection circuits to ensure the safety of the amplifier and connected speakers. Its compact size and low heat dissipation make it a popular choice among audio enthusiasts and professionals alike. Overall, the TPA3126 IC offers an efficient, reliable, and high-quality solution for audio amplification needs.
About MH-M18 Bluetooth module
The MH-M18 Bluetooth module is a compact and versatile wireless communication solution. It utilizes the Bluetooth 4.2 technology, allowing for seamless and reliable connections with other Bluetooth-enabled devices. This module offers a range of up to 10 meters, making it suitable for a variety of applications. Its small size and low power consumption make it ideal for integration into portable devices or IoT projects. The MH-M18 module also features a built-in microphone and speaker, enabling easy audio communication. With its simple interface and easy-to-use AT commands, this Bluetooth module provides a convenient and efficient solution for wireless connectivity needs.
BOM Mini D class power amplifier with preamplifier
| Name | Value | Description | Quantity |
| Resistors | |||
| R1, R2, R3, R4, R12 | 10k (103) | 0603 SMD resistor | 5 |
| R5, R6 | 100K (104) | 0603 SMD resistor | 2 |
| R7 | 20K (203) | 0603 SMD resistor | 1 |
| R8, R9, R10, R11 | 3.3 Ω (3r3) | 0603 SMD resistor | 4 |
| RN1,RN2,RN3,RN4,RN5,RN6,RN7,RN8,RN9,RN10 | 10 kΩ (103) | 10 kΩ 0603×4 Resistor Network | 10 |
| U1,U2,U10,U12 | RV097NSB50K | Potentiometer 50k | 4 |
| Capacitors | |||
| C1,C2 | 220uF/35V | SMD electrolytic capacitor | 2 |
| C4 | 220uF/16V | SMD electrolytic capacitor | 1 |
| C5,C6,C7 | 3.3uF | 0603 SMD ceramic capacitor | 3 |
| C12, C13, C14, C15, C16 | 1uF | 0603 SMD ceramic capacitor | 5 |
| C17, C18, C19, C20 | 220nF | 0603 SMD ceramic capacitor | 4 |
| C21, C24, C27, C30 | 680nF | 0603 SMD ceramic capacitor | 4 |
| C8, C23, C26, C29, C32 | 10nF | 0603 SMD ceramic capacitor | 6 |
| C9, C33 | 100nF | 0603 SMD ceramic capacitor | 2 |
| C10, C22, C25, C28, C31, C34 | 1n | 0603 SMD ceramic capacitor | 6 |
| Semiconductors | |||
| LED1,LED2 | Red LED 0603 | Red LED 0603 | 2 |
| Q1 | NCE3090K | 30V 90A 5.8 mΩ@10V,20A 105W 2.5V@250uA N Channel TO-252-2(DPAK) MOSFETs | 1 |
| U3 | TPA3126D2DAD | HTSSOP-32 — 50-W Stereo, Analog-Input, Class-D Audio Amplifier with Low, 15-mA Idle Current and AM Avoidance | 1 |
| U4,U5 | LM324DT | SOIC-14 — Quad 1.3MHz Operational Amplifier | 2 |
| U6 | LM2596S-5.0/TR | TO-263-5 — DC-DC Converters 5V | 1 |
| U9 | MH-M18 | MH-M18 Bluetooth module | 1 |
| U11 | SGM3204YN6G/TR | -5.5V~-1.4V 200mA 1.4V~5.5V SOT-23-6 DC-DC Converters | 1 |
| Miscellaneous | |||
| CN1 | XT30PW-M | CONN-TH_XT30PW-M | 1 |
| CN2,CN3,CN4 | XH2.54-2PIN- | Connector 2 pin 2.54 mm | 3 |
| D1 | SS34 | SMA — Schottky diode | 1 |
| DC1 | DC-042C-W-2.0 | DC Power Receptacle 6.3 mm | 1 |
| J1,J2,J3 | PJ-307C | 3.5 mm headphone jack | 3 |
| L1 | 33uH (330) | 3A 33uH SMD Power Inductors 12×12 mm | 1 |
| L2,L3,L4,L5 | 10uH (100) | 6.5A 10uH Shielded Power Inductors 11.6×10 mm | 4 |
| U8 | BFS1206 32V 5A | 1206 SMD fuse | 1 |
| U14,U15 | KF301-5.0-2P | 5 mm 1.5 1 2 Plugin, P=5mm Screw terminal | 2 |
Download files, links, and notes
Download PCB in Gerber, PDF + Case 3D
- Buy TPA3126D2 IC
- Buy MH-M18 Bluetooth module
- Manual PDF datasheet MH-M18 Bluetooth module
- PDF datasheet IC TPA3126D2 — 50-W Stereo, Analog-Input, Class-D Audio Amplifier with Low, 15-mA Idle
Current and AM Avoidance - TPA3126D2EVM — TPA3126D2 Inductor Free 50W Stereo (BTL) Class-D Audio Amplifier Evaluation Module
Source: https://oshwhub.com/longhuan/duo-tong-dao-d-lei-yin-pin-gong-lv-fang-da-qi
