Abstract: An isolation regulator including a regulator circuit couples a source of power to an electrically noisy dc load connected in parallel with a load capacitor. Peak noise across the load is used to control the regulator circuit to set the current level to the load and determine the operating set point of the regulator circuit which includes a FET operated close to saturation to minimize the voltage drop across the FET. The illustrated electrically noisy dc load is a dc motor and the peak noise is the peak ripple across the motor which is monitored and compared to the saturation voltage of the FET. Positive peaks of the ripple, which could cause the FET to saturate, control the regulator circuit to reduce current flow and prevent saturation. Current provided by the regulator circuit increases gradually over time and is reduced as necessary by positive peak ripple signals to provide stable current flow to the dc motor. As illustrated, the dc motor drives a fan which cools associated electrical equipment.