P1684 Diagnostic and Engine Stalling in 2000 Dodge Intrepid 2.7L

I own a 2000 Dodge Intrepid with a 2.7L engine and approximately 105,000 miles on the odometer. This afternoon while shopping at Target, I noticed the radio stuttered during our drive — it would suddenly stop for about 2 seconds before returning to normal. This occurred twice when we changed stations. Later, as we were traveling on the interstate at around 65 mph, the vehicle unexpectedly shut off for approximately 2–3 seconds. It felt like a sudden hard brake application, and all dashboard lights dimmed. However, the engine restarted immediately, and I was able to continue driving safely until reaching our next exit. After exiting, while approaching a stoplight at about 25 mph and gradually slowing down with my foot on the brake, the same shutdown event happened again. About five minutes later, as we were pulling into our neighborhood, the battery warning light illuminated. I attempted to retrieve diagnostic trouble codes using the ignition cycle (on-off-on-off-on), which returned code P1684 and then displayed 'DONE'. I'm seeking advice on what this error might indicate and how to resolve it. My wife is quite concerned, so any insights would be greatly appreciated. Thank you in advance for your help!