Parasitic power supply and sensor apparatus including a power supply

摘要

A parasitic power supply derives power from its proximity to an electrical power conductor. The power supply includes a transformer having a coil disposed on a core structured to be disposed parallel to the power conductor. The coil has a voltage induced by current flowing in the power conductor. A voltage regulating circuit cooperates with the transformer and includes a capacitor having a voltage, a charge switch structured to charge the capacitor from the coil voltage, a bootstrap circuit structured to enable the charge switch to charge the capacitor when the capacitor voltage is below a first predetermined value, a charge controller structured to enable the charge switch to charge the capacitor when the capacitor voltage is below a second predetermined value, and a voltage regulator powered by the capacitor voltage.

主权项

1. A parasitic power supply for an electrical power conductor for outputting a desired voltage to an electronic device coupled to said power supply, said power supply comprising:
a transformer comprising a coil disposed on a core structured to be disposed parallel to said electrical power conductor, said coil having a voltage induced by current flowing in said electrical power conductor, and a voltage regulating circuit cooperating with said transformer, said voltage regulating circuit comprising:
a capacitor having a voltage,a charge switch structured to charge said capacitor from the voltage of said coil,a bootstrap circuit downstream of the coil, the bootstrap circuit being structured to enable said charge switch to charge said capacitor responsive to the voltage of said capacitor being below a first predetermined value and above a second predetermined value and responsive to the voltage of said capacitor being below a third predetermined level but, not when the voltage of said capacitor is below the second predetermined value and above the third predetermined value, wherein the first predetermined value is greater than the second predetermined value and the second predetermined value is greater than the third predetermined value,a charge controller structured to: (i) disable and lock out the bootstrap circuit responsive to the voltage of said capacitor being above the third predetermined value, and (ii) enable said charge switch to charge said capacitor by turning on a drive current to the charge switch responsive to the voltage of said capacitor being below the second predetermined value and above the third predetermined value, anda voltage regulator downstream of said capacitor, said charge switch, said bootstrap circuit, and said charge controller and powered by the voltage of said capacitor, wherein an output of said voltage regulator is said desired voltage output to said electronic device.