Designing a class D amplifiers

Project Info


Our client requested designing an amplifier composed of two Class D amplifiers, one with an active crossover, and the other one having an additional Bluetooth APTX chip for a wireless input.


The requirements set by the client included the followings

  1. Two Class D amplifier, each with the power of 80W
  2. Each amplifier having an active crossover with the frequency cut at 3000Hz
  3. One unbalanced input, one balanced input, and one Bluetooth input.
  4. Making all the design on the same PCB
  5. Everything must be on the same PCB


Some of the main challenges in proceeding with the design included the followings

  • Everything was to be included on the same board
  • The client had already made the enclosure, so we had to adapt the design to the enclosure


In order to proceed with the project, an initial block diagram with all the requirements was prepared and submitted to the client with 3 different plans to make the Amplifier.

The client was satisfied and chose the second plan.
Regarding the size requirement, we made two designs and finally the smaller board sized 11cm x 11cm was chosen as it was suitable for the given enclosure.

The design team completed the main board and also a small board for the Bluetooth keys. The final design had the following features:

  • The Bluetooth receiver was mounted on the main board
  • For the power supply, an AC 100-240V to DC 24V 6A 150W Power Supply and an AC-DC Power Module Board Switch was considered.
  • The inputs and outputs were located according to the enclosure
  • The final size was changed to 11cm x 11cm as was requested by the client.

The final result was quite compatible with the requirements and the client provided the following feedback for the work: “Meee did a mind-blowing job! This was far beyond my expectations.
I strongly recommend Meee-services to anyone who’s looking for a professional job done by someone with solid experience!”

J. Johnson
March 26, 2018
Electrical and Electronic Engineering