Constant current startup regulator for fault managed power

An apparatus comprising:

• a first power switch and a second power switch, the first power switch coupled to a send line over which power is received from a power transmitter at a power receiver, and the second power switch coupled to a return line in the power receiver,
• a controller configured to control the first power switch and the second power switch to open during power-off times and to close during power-on times;
• and
• a current source coupled to the send line and configured to output a constant current at a predetermined level on the send line during the power-off times such that the power transmitter observes the constant current during safety check intervals that correspond to the power-off times,
• wherein the controller receives power, derived from the constant current, to power the controller for a period of time.

A method performed by a power receiver that receives power from a power transmitter, the method comprising:

• receiving pulse power from the power transmitter on a send line and a return line, the pulse power comprising alternating pulse-on times and pulse-off times, the power transmitter performing a safety check for a fault during safety check intervals that correspond to the pulse-off times;
• providing, from a current source at the power receiver, a constant current at a predetermined level on the send line during the pulse-off times such that the power transmitter observes the constant current during the safety check intervals when there is no fault on the send line and return line;
• and
• coupling power, derived from the constant current, to a controller in the power receiver to power the controller for a period of time.