I'm trying to build a motor driver which can supply ~3A per motor. Only cheap IC I could get my hands on was L298, so I decided to parallel its channels. But for some reason that I can't understand (I'm merely an amateur hobbyist), L298 and its diodes are getting too hot in just a matter of seconds.

I'm using a 12V (max 40W) power supply for my circuit, and its reduced to 0.95V when I check VCC/GND pins (how is that even possible ?)

This is my PCB design.

47uF capacitors,

1N5819 diodes,


enter image description here

Edit: Schematics enter image description here

  • \$\begingroup\$ Can you please post your circuit schematic diagram? Not everyone will have the luxury of time understanding your issue by mapping PCB traces and pin connections. \$\endgroup\$
    – shimofuri
    Nov 30, 2012 at 12:55
  • \$\begingroup\$ I suspect you have a short somewhere, or one of your diodes is the wrong way round. Your silkscreen layer is a bit mangled and one of your labels is upside down.. \$\endgroup\$
    – pjc50
    Nov 30, 2012 at 12:56
  • 1
    \$\begingroup\$ What's a L298? What's your circuit? It should have been obvious that you need to link to the datasheet and provide a schematic. \$\endgroup\$ Nov 30, 2012 at 13:15

1 Answer 1


You haven't labelled + and - on your battery!

Assuming that battery pin 1 is positive, because it's connected to VS of the L298, then your diodes are the wrong way round in the schematic.

Edit: the 0.9V is exactly as expected, as that's the forward voltage of the diode. You're sinking the full current of your power supply through a diode and the L298.

  • 2
    \$\begingroup\$ Your PCB seems to contradict your circuit diagram in this all-important aspect. The PCB seems to be OK. \$\endgroup\$ Nov 30, 2012 at 13:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.