Methods and apparatus for supplying power for use in metering electrical
energy over a wide range of voltages with a single meter are disclosed.
The wide ranging meter includes a processing unit for processing divided
input voltage and a current component in order to determine electrical
energy metering values. The processing unit is operable in response to
supply voltages. A power supply, connected to receive the undivided
voltage component, generates the supply voltages over the wide dynamic
range. It is especially preferred for the power supply to include a
transformer having first, second and third windings, wherein the
undivided voltage component is provided to the first winding and wherein
the second winding defines the output of the power supply. A switching
member is connected to the first winding for permitting and preventing
the flow of current in response to a control signal. A control member
generates the control signal in response to the output of the power
supply. It is also preferred for the control signal to disable the witch
member. It is further preferred for the power supply to include a voltage
blocking clamp, connected to the transformer for blocking the voltage
applied to the transformer. It is still further preferred for an
oscillator to be used to generate an oscillating signal for switching the
switching member ON and OFF so that the switching member is provided a
substantially constant OFF time.