Project: TA1000PS - PSU for audio amplifiers with protection, sofstart and fan contro

Discussion in 'The Completed Projects Collection' started by donpetru, Jul 20, 2014.

  1. donpetru

    Thread Starter Senior Member

    Nov 14, 2008
    TA1000PS is a free project that wants to fill the need for electronic kits for complete realization of a high power amplifier.

    TA1000PS includes: a DC voltage protection on the output amplifier, speaker delay, fan speed control to cool amplifiers heatsinks and one output +/-12Vdc to power an audio preamplifier.

    The software will be written in the microcontroller is attached below.

    From the construction point of view, as you will notice, the schematic TA1000PS is divided into:
    - A power supply circuit for audio amplifiers (includes a bridge rectifier and filtering capacitors = four pieces of 10000uF-100V);
    - One output +/-12V DC for the power relay = 24Vdc/20 or 30amps (including the related protections) and for the power external circuit, such as an audio preamplifier;
    - A circuit or a separate power supply, electrically isolated, to power two fans (one fuzzy controller with Atmel MCU (Attiny45) but you can also use Attiny85). The software MCU I will post below;
    - a filter on the 230 VAC supply.

    The software I can customize it, for example, if you want the DC fans to respond differently to various temperature thresholds. This is necessary because, in a certain situation, how fan speed variation with temperature may not be the most suitable. The cost will be a modest if you want only change temperature range (eg, $ 10).

    Noted that the above software has been designed on the following fields of temperature:
    - 0 ... 40 degrees C - speed 0, fan off
    - 40 .. 55 degrees C - about 40% of rated speed
    - 55 ... 70 degrees C - about 70% of rated speed
    - 70 ... 85 degrees C - nominal speed;
    - 85 degrees C - thermal protection on each channel amplification part (the fan runs at full speed). If the temperature drops below 85 gr. Celsius, the controller resumes normal operating cycle.

    Depending on the type of fan used can record small variations in measurements mentioned above. The project was designed to operate with 12VDC fans (max. 0.75A) but can be adapted (by change two resistors) and for 24VDC fans. Of course, the input power brigde voltage will be higher if you want to use 24VDC fans.
    For temperature measurement, I used two pieces LM35, one on each channel.

    This project has been tested and works flawless.

    P.S. Unfortunately, PCB's have not done because there was not enough users on my site to subscribe.

    I hope you enjoy this free project and if there are any questions, please ask in this thread.
    Last edited: Sep 21, 2014
  2. bertus


    Apr 5, 2008

    I uploaded the PDF for you as it is required to be allowed in the completed projects forum.


    PS you should be able to upload PDF upto 5 Mb.
    Last edited: Jul 20, 2014
  3. donpetru

    Thread Starter Senior Member

    Nov 14, 2008
    Thank you. Meanwhile I deleted the web link to external URL.
  4. donpetru

    Thread Starter Senior Member

    Nov 14, 2008
    I have attached in the first post the updated version of the software to be written in MCU Attiny45. Unlike the previous version, the new version I changed the output activation "shut-down Ch-A" and "shut-down Ch-B". Specifically, if you use version 1.0.0, when the heatsink of Ch-A exceeded the maximum allowable temperature, then the MCU control, according to PCB, the corresponding relay channel B, which was not well. I corrected this deficiency and from now on I recommend you load the MCU version 1.0.1.
    For those users who are using version 1.0.0, so you can not change the software from MCU, because once overwritten it is harder to reset fusebit and write MCU flash again, you can do one of the following permutations:
    1) permuted faston connectors from input-output power relays K1 and K2;
    2) permuted LM35 connectors and fan power connectors between the two audio channels.
    Both solutions above are easy to do because it does not requires change the PCB tracks wiring.
    Remember, you have to apply only one solution of the two mentioned above and only if you use version 1.0.0.