Patent ID: 8867187

Claim:
A power adapter comprising: a first connector communicatively coupled with a plurality of conductors; a second connector communicatively coupled with two or more of the plurality of conductors; and a shunt communicatively coupled with at least four of the plurality of conductors and configured to provide power to an accessory output in response to an accessory connection being communicatively coupled with an accessory device, the shunt including: a protection circuit, the protection circuit configured to provide at least one of protection from overcurrents and protection from excessive transient voltages at a first, a second, a third, and a fourth inputs, the first, the second, the third, and the fourth inputs each communicatively coupled with the at least four conductors of the plurality of conductors; an inductive coupler including: a first transformer having a primary coil communicatively coupled with the first input and the second input, and a second transformer having a primary coil communicatively coupled with the third input and the fourth input; a main rectifier comprising: a first rectifier communicatively coupled with the first input, the second input, a first node, and a second node; and a second rectifier communicatively coupled with the third input, the fourth input, the first node, and the second node, and a failsafe including: a first output, the first output being communicatively coupled with a first conductor of the accessory output; a first switch communicatively coupled with the first node and the first output; a first power supply including a first secondary coil of the first transformer and a third rectifier, a first secondary coil of the second transformer and a fourth rectifier communicatively coupled with the first switch; a first opto-isolator communicatively coupled with the first output and the first switch; a second output, the second output communicatively coupled with a second conductor of the accessory output; a second switch communicatively coupled with the second node and the second output; a second power supply including a second secondary coil of the first transformer and a fifth rectifier, a second secondary coil of the second transformer and a sixth rectifier communicatively coupled with the second switch; a second opto-isolator communicatively coupled with the second output and the second switch; a loop input, the loop input communicatively coupled with a third conductor of the accessory output and the second opto-isolator, the second opto-isolator communicatively coupled with the first opto-isolator; and a loop output, the loop output communicatively coupled with the first opto-isolator, a third power supply, and a fourth conductor of the accessory output; the third power supply including a third secondary coil of the first transformer and a seventh rectifier, a third secondary coil of the second transformer and an eighth rectifier communicatively coupled with the loop output.