Power supply with current limit on individual conductors

A power supply comprising:

• a power source;
• a first switch coupled to an output of the power source;
• a first resistor having a first terminal coupled to the first switch;
• a second resistor having a first terminal coupled to the first switch;
• a first current sense circuit having a first input coupled to the first terminal of the first resistor, a second input coupled to a second terminal of the first resistor, and an output coupled to a control input of the first switch;
• and
• a second current sense circuit having a first input coupled to the first terminal of the second resistor, a second input coupled to a second terminal of the second resistor, and an output coupled to a control input of the first switch.

A method of using a power supply to provide power over a cable, the method comprising:

• detecting that a first connector at a first end of the cable is properly connected to a second connector;
• and
• providing a first power supply voltage over the cable to a first circuit coupled to the second connector;
• and
• receiving a response from the first circuit;
• then
• providing a second power supply voltage over the cable, otherwise
• not providing the second power supply voltage.