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I am designing a circuit for the CHIP Microcomputer and I want to enable audio output using headphones OR a speaker. For clarification, when the user plugs in headphones, I want the speakers to be disabled. The CHIP has a headphone jack and provides access to the HPL, HPR and HPCOM signals, but doesn't appear to give me access to the Headphone detect signal from the headphone jack's detect switch.

How should I go about doing this? Can I use the HPL and HPR signals with an external amplifier for the speaker? If so, how do I set the SHUTDOWN signal to disable the speaker when headphones are inserted? Should I use an external audio codec? How do I know if an audio codec mutes the LINEOUT signals when the HPOUT signals are in use or how do I use the detect switch of a headphone jack to accomplish this?

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The LM4863 is a dual amp with headphone functionality. Its datasheet shows exactly how to connect speakers and a headphone jack to implement the application you describe.

LM4863 Typical Application

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  • \$\begingroup\$ Not a bad idea. I will likely use the LM4868 since the LM4863 is not available on Digikey (my current distributor for this project). Regardless, it seems as though I don't have access to the Control Pin of the built-in headphone jack (grr) so I will likely need to use an external one. \$\endgroup\$ – Nate Aug 12 '15 at 22:24
  • \$\begingroup\$ Isn't that it on PMU-GPIO1? \$\endgroup\$ – Ignacio Vazquez-Abrams Aug 13 '15 at 0:52
  • \$\begingroup\$ Yes, but I have no way of accessing that signal from any of the device's external pins. \$\endgroup\$ – Nate Aug 13 '15 at 1:26
  • \$\begingroup\$ Also I meant LM4838 not LM4868. \$\endgroup\$ – Nate Aug 13 '15 at 19:13

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