Abstract: Methods and an arrangement for transmitting electrical power from a power source to a remote load over a telephone twisted pair are provided so as to power the load. The power source may transmit a plurality of electrical power feeds over a plurality of twisted pairs, each power feed limited to no more than 100 watts in a given twisted pair. One or more (or all) of a plurality of independent, power converters at the remote load may generate a voltage output based on receipt of a given power feed from a corresponding twisted pair.

Abstract: A constant power circuit for causing a constant power level to be dissipated by a load when an overpower condition is detected. The overpower condition is detected by measuring the voltage across and current drawn by the load in accordance with a programmed load value and determining whether the sum of the measured current and voltage exceeds the power limit for the load. In a preferred embodiment, the sum of the voltage and current is compared to a linear piecewise approximation of a constant power curve in the current-voltage plane, the curve representing the power limit for the load for the range of current and voltage magnitudes in which the load circuit may safely operate. When an overpower condition is detected, the power is dissipated by the load at a constant power level defined by the constant power limit by oscillating the power level within a hysteresis band about the constant power limit.