A floor care appliance is provided with an improved power management
system for controlling the total amount of current provided to at least a
first and a second load device of an appliance. The power management
system is comprised of a microprocessor, an alternating current voltage
source, a voltage regulating circuit, a clamping circuit, at least two
load devices, and a MOC and a triac for each of the at least two load
devices. The clamping circuit outputs a fixed voltage of 5.7 volts during
the positive portion of the ac cycle and a fixed voltage of -0.7 volts
during the negative portion of the ac cycle. The fixed voltages are input
to a microprocessor which utilizes these inputs to control the average
voltage and the amount of time the current is turned on to each of the at
least first and second load devices. A current sensing circuit is used to
monitor the current to one of the at least two load devices to provide
feedback to the microprocessor so that the microprocessor can adjust the
average voltage and current to the at least two load devices so that the
total current consumed does not exceed a pre-determined level.