A power supply for a two-wire load control device supplies power to a
microprocessor, which in turn controls the power supply. The power supply
comprises an energy storage element, e.g., a capacitor, for producing a
DC voltage for powering the microprocessor. The power supply comprises a
high impedance circuit for allowing the energy storage element to receive
energy at a first rate before the DC voltage is produced and the
microprocessor is powered. The power supply further comprises a
low-impedance circuit, i.e., a resistor in series electrical connection
with a controllably conductive device, for allowing the energy storage
element to receive energy at a second rate greater than the first rate.
After starting up, the microprocessor is operable to selectively enable
and disable the second energy-receiving circuit by rendering the
controllably conductive device conductive and non-conductive,
respectively. The microprocessor is operable to monitor the power supply
and to control the amount of power delivered to an electrical load
connected to the load control device in response to the monitoring of the
power supply.