Patent ID: 6389135
Filing Date: 2002-05-14
Classification: H02M,H04L,H04M

Abstract:
Circuitry transferring power and a digital signal from a system side to a line side of a telephone line interface circuit comprising:a capacitive isolation device having a voltage rating selected for providing a desired level of isolation, said capacitive isolation device comprising a first capacitor having a first terminal coupled to a first output of said system side, and a second capacitor having a first terminal coupled to a second output of said system side; a charge storage device comprising a third capacitor for developing a supply voltage for supply to said line side; and a diode circuit comprising a first diode having its cathode coupled to a second terminal of said first capacitor and its anode coupled to a second terminal of said second capacitor to allow discharging of said first and second capacitors when said second output of said system side is at a high voltage level relative to said first output of said system side, and a second diode having its anode coupled to said first capacitor and its cathode coupled to said third capacitor to allow charging current to flow to said third capacitor when said fist output of said system side is at a high voltage level relative to said first output of said system side.