A very strange TDA8560q problem

[riko4628]

Is it normal that TDA8560q drains 3A current without load?

 

[Arty]

nope.
it could be oscillating like mad.
schematic, and actul build ?

 

[riko4628]

I built it, then i spotted it got realy hot (i used just small heatsink) and then i tested it with ampermeter and it draws 3 ampers without any input, but it sounds fine

 

[JonSnell Electronic]

Sounds like it is taking off at a very high frequency. Check the decoupling capacitors.

 

[riko4628]

Sorry but what is decoupling capacitor? I dont know what does it mean in english. Sorry

This is the schematic i'm using but i'm powering it from 12v lead acid battery:http://img.hw.cz/k/Konstrukce-zesilovace-TDA8560Q-pro-PC/Obr6.png

 

[johnr66]

These chips are VERY sensitive to grounding issues. The power supply decoupling capacitor (capacitor that connects from the power lead to the ground lead) must be very close to the pins of the IC. Signal ground must be not be between the power ground and ground pin on IC or the IC may oscillate. I didn't check this IC, but some have a separate signal ground pin.

Also if no input signal is connected, the high impedance inputs will "receive" output signal and cause oscillation. In this case, lower the input impedance by adding a resistor from input to signal ground. Connect this resistor to the pin on the cap that is opposite the one connected to the IC. If using a volume pot, you should not need this.

Twist your input and input ground leads together.

 

[riko4628]

Ok guys, today i fixed it. I just disconnected the signal gnd from power gnd as johnr66 said. Thank you 😉