Signal isolation circuit

A signal isolation circuit, comprising:

• a line;
• a transmit portion having a first input, and having a first output coupled to the line, the transmit portion being configured to transmit a wakeup signal on the line, followed by an encoded transmission on the line, the encoded transmission representing an input signal at the first input;
• a receive portion having a second input coupled to the line, and having a third input, the receive portion being configured to operate in:
• a wake mode in which the receive portion is capable of receiving the encoded transmission via the second input;
• and a sleep mode in which the receive portion is incapable of receiving the encoded transmission via the second input;
• and
• a wakeup controller having a fourth input coupled to the line, and having a second output coupled to the third input, the wakeup controller being configured to:
• monitor the line for the wakeup signal;
• and responsive to the wakeup signal, provide a signal at the second output to cause the receive portion to enter the wake mode.

A method, comprising:

• receiving an input signal at a transmit portion;
• providing a first wakeup signal on a line in response to the input signal;
• receiving the first wakeup signal on the line at a wakeup controller;
• providing a second wakeup signal to a receive portion, the receive portion waking from a sleep mode in response to the second wakeup signal;
• transmitting an encoded transmission representing the input signal from the transmit portion to the receive portion on the line;
• and
• receiving the encoded transmission at the receive portion, and decoding the encoded transmission.