I recently built a simple audio amp based on the TPA2005D1. The schematic is identical to the one that Sparkfun implemented in their Mono Audio Amp breakout board, minus the power LED circuitry.


I wired this up to a headphone jack and a speaker. The headphone jack is a traditional switched jack that diverts audio to the speaker when there is no jack plugged in, the diagram below is for the exact jack I'm using.

Vo+ is hooked up to pins 2 and 3, Vo- is hooked up to pin 4, the speaker is hooked up to pins 5 and 6 on the positive speaker terminal and pin 4 on the negative speaker terminal.The sleeve is not hooked up to anything at this point.

The exact jack that I'm using. The sleeve is not connected at this point.

The problem I'm having is when I plug or unplug headphones, the Vo- and Vo+ pins short together momentarily inside the jack and trigger the short circuit detection built into the TPA2005D1. I have to power cycle the amp or pulse the shutdown line to get it to work again. The short circuit protection can be seen in the bottom right corner of the TPA2005D1 functional block diagram.

enter image description here

Is there any way to increase the amount of time a short circuit can occur? Maybe up to a quarter second? Is there a simple way to pulse the shutdown line every time I plug/unplug headphones?

  • \$\begingroup\$ You could use another amp that recovers itself. \$\endgroup\$ – PlasmaHH Sep 14 '17 at 8:10
  • \$\begingroup\$ I could, but I'd like to avoid that if possible. \$\endgroup\$ – qaxf6auux Sep 14 '17 at 8:15
  • \$\begingroup\$ Well, it seems that this part is designed mainly towards fixed 8Ω speakers, not headphones.... also what time do you want? You will always find someone exceeding that time, rendering the device unusable for the unwary user. \$\endgroup\$ – PlasmaHH Sep 14 '17 at 8:37
  • \$\begingroup\$ I'd like to increase it to around quarter second or so. Just enough to pull the headphones out. Although you're right, this was designed for speakers, not headphones. \$\endgroup\$ – qaxf6auux Sep 14 '17 at 8:41
  • \$\begingroup\$ What are you going to do if someone plugs it in only halfway? \$\endgroup\$ – PlasmaHH Sep 14 '17 at 8:43

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