A flow meter is powered by a loop power supply which supplies a supply voltage. A load is powered by a load voltage and includes at least a processor for calculating a flow rate, an ultrasonic transducer power circuit, and an ultrasonic transducer receiving circuit. A power regulating circuit is disposed between the loop power supply and the load and includes a power converter responsive to the supply voltage to vary the load voltage in response to a control signal, a safe storage device between the converter and the load for storing power and for delivering power when required by the load, and a control subsystem for providing the control signal to the converter based on the setting of the loop power supply by the load. A power management detects the load voltage and to reduces the power consumption of the load at one or more predetermined set points.