Squelch Detection Method and Circuit Using Dual Rectifying Circuit for Detecting Out-of-Band Signal

A method comprising:

• generating a first output component of a differential output signal by a first differential circuit level shifting and positively rectifying a differential input signal;
• generating a second output component of the differential output signal by a second differential circuit level shifting and negatively rectifying the differential input signal;
• generating first and second fixed voltages in a third differential circuit based on an input reference voltage and a ground voltage;
• asserting a signal responsive to a comparator determining that a voltage difference between the first and second components of the differential output signal is greater than a difference between the first and second fixed voltages.

An integrated circuit comprising:

• a detector coupled to receive a differential input signal from an external device, and wherein the detector includes:
• a first differential circuit configured to level shift and positively rectify an differential input signal to produce a first output component of an differential output signal;
• a second differential circuit configured to level shift and negatively rectify the differential input signal to produce a second output component of the differential output signal;
• and
• a third differential circuit configured to level produce and output first and second fixed voltages based on an input reference voltage and a ground voltage;
• wherein the detector is configured to provide an indication when the differential output signal has a differential voltage greater than a difference between the first and second input voltages responsive to a request from the external device.