Simple Solid State Relay For Low Wattage Class D Power Amplifier

For months I'm playing a lot with this tiny amplifier. It is 12 volt capable, low watt, yet ultra efficient power amplifier that very suitable for car audio application. It producing high quality audio with flea watt that most any mid-range or full-range speakers can accept. Previously, this auto power-on amplifier is controlled by using a mechanical relay. It is okay and not any single problem occurs. But to make it less mechanical things, I built the simple solid state relay in it.

By looking inside this amplifier, it is powered by TA2024 by Tripath. I already modify the board for DC output bias adjustment as per datasheet and several components upgrade to tailored the sound just what I prefer most.

I starting this project with plain universal PCB. I measure and cut it to fit inside the amplifier case. I don't have to planning on how much components will be put on it, as long as I think it is sufficient, then I cut it.

The main components of this solid state relay is no more than a single NPN transistor. I choose any transistor from my bin, it is used Motorola 2N6488. This transistor is capable for 75 watt power, plenty head room if you can count for this project.

That is why you are actually doesn't need heat sink! Adding one like this actually for support the transistor in it's place.

Caution should be made when installing the transistor to the heatsink. Washer and lug should be use to prevent the short circuit.

Populated the components, is quite easy. 2 big capacitor from Nichicon FW, a zenner diode, capacitor and resistor.

Then, attach all the cable in place.

This is the final layout. It is simple and looking good.

Perhaps you might ask about the schematic, then I drawing this for you.

That's it, a simple solid state relay that using few parts and this is also act as a voltage regulator.

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