Isolation system with digital communication across a capacitive barrier

An isolation system for transmitting a digital data signal across a capacitive telephone line isolation barrier, comprising:

• one or more isolation capacitors;
• means for providing a digital signal to a first side of the isolation barrier;
• means for receiving a plurality of isolated signals from a second side of the isolation barrier;
• clock circuitry producing a clock signal from at least one of the isolated signals;
• means for synchronizing at least one isolated signal with the clock signal;
• and
• an isolated power supply circuit coupled to at least one of the isolation capacitors, the power supply circuit generating a DC power supply from at least one of the isolated signals received across the capacitive telephone line isolation barrier.

An isolation system for providing a digital communication channel between a powered circuit and a phone line side circuit, the isolation system comprising:

• a capacitive isolation barrier for isolating a telephone line from the powered circuit;
• a clock recovery circuit located on an isolated side of the capacitive isolation barrier;
• and
• at least one isolated signal on the isolated side of the isolation barrier, the isolated signal being transmitted across the capacitive isolation barrier;
• wherein the clock recovery circuit is adapted to provide a recovered clock signal based on the at least one isolated signal received from the powered circuit across the isolation barrier, the recovered clock signal being substantially free of phase noise.

A bidirectional isolation system for providing an isolated communication channel for data signals in a forward direction and in a reverse direction across an isolation barrier comprised of one or more isolation elements, the system comprising:

• a powered system on a first side of the isolation barrier, the powered system connected to the isolation barrier for driving a forward direction digital signal across the isolation barrier;
• and
• an isolated system on a second side of the isolation barrier, the isolated system connected to the isolation barrier for driving a reverse direction digital signal across the isolation barrier;
• wherein the forward direction digital signal and the reverse direction digital signal are both driven through the same isolation element, and wherein the isolated system receives at least some power from across the isolation barrier.

An isolation system for providing a digital communication channel for telephone line data signals and control signals, the isolation system comprising:

• an isolation barrier comprised of a plurality of isolation elements;
• a multiplexer located on the telephone line side of the isolation barrier and coupled to receive the telephone line data signals and the control signals and providing a multiplexed digital signal that is coupled to the isolation barrier;
• a demultiplexer located on the other side of the isolation barrier and connected to receive the multiplexed digital signal from the isolation barrier, the demultiplexer having a data signal output and a control signal output;
• and
• power circuitry on the telephone line side of the isolation barrier coupled to at least one signal transmitted across the isolation barrier, the circuitry providing a power supply on the telephone line side of the isolation barrier that powers at least a portion of some circuitry on the telephone line side of the isolation barrier.

An isolation system for providing digital communication across a telephone line capacitive isolation barrier having one or more capacitors, comprising:

• a transmit circuit located on a first side of the isolation barrier for providing a transmitted digital signal to be communicated across the isolation barrier;
• a receive circuit located on a second side of the isolation barrier for receiving a received digital signal from the isolation barrier;
• a clock circuit located on the second side of the isolation barrier and coupled to the receive circuit, the clock circuit generating a timing signal from information transmitted across at least one of the capacitors;
• and
• a power supply circuit located on the second side of the isolation barrier, the power supply circuit generating a power supply from information transmitted across at least one capacitor of the isolation barrier.