An RMR is biased with constant power. Voltages are applied across at least two variable resistors, which are coupled on opposing ends of the RMR, to establish a current to the RMR, wherein the current is based on the voltages and on resistance values of the at least two variable resistors. A voltage corresponding to the established current of the RMR is amplified. The amplified voltage is compared to a reference voltage, wherein the reference voltage is based on a target power for the RMR. The resistance values of the at least two variable resistors are modified so that the amplified voltage approaches the reference voltage. Modifying the resistance values of the at least two variable resistors in this manner is seen to bias the RMR with constant power, since the reference voltage is based on a target power for the RMR.