Patent ID: 6768228
Filing Date: 2004-07-27
Classification: H02H,H04N

Abstract:
A device to determine a resistive load connected to a source of alternating current (â€œACâ€ ) power, comprising:a. a signal path and an AC power path, both paths connected to a device input and a device output; b. a processor connected to a sensing circuit including a sensing resistor that determines a current level in said AC power path, said processor indicating an off condition according to said current level on said sensing resistor; c. a control circuit that turns off said AC power to said device output when instructed by said processor at said off condition, wherein said control circuit comprises a first field effect transistor and a second field effect transistor coupled to a transistor, said transistor coupled to the gates of said first and second field effect transistors; and d. a circuit to control AC power to a load, comprising: a1. a first resistor and an electronic switch connected in series to a source of direct current (â€œDCâ€ ) power; b1. said first field effect transistor having a drain connected in series with said load and said AC power; c1. said second field effect transistor having a source connected in series with a source of said first field effect transistor, wherein the drain of said second field effect transistor is connected to ground; d1. a clamping diode having a cathode and an anode, wherein said cathode is connected to the gate of each of said first and second field effect transistors, and wherein the anode of said clamping diode is connected to the source of each of said first and second field effect transistors and to the end of said series connection of said electronic switch and said first resistor opposite to said DC power source; and e1. a second resistor connected in parallel to said clamping diode.