APPARATUS AND METHODS FOR LOSS OF SIGNAL DETECTION

Apparatus and methods for loss of signal detection are provided. In one embodiment, a detection circuit for monitoring an input includes a small signal boost circuit, a rectifier circuit, a low-pass filter, and one or more comparators. The small signal boost circuit can generate an amplified signal by providing a first amount of gain to an input signal when the input signal is relatively small, but can saturate and provide reduced gain without external gain control adjustment when the input signal does not have a relatively small magnitude. The rectifier circuit can rectify the boosted signal to generate a rectified signal, and the low-pass filter can filter the rectified signal to generate a filtered signal. The one or more comparators can compare the filtered signal to one or more decision threshold voltages to determine the presence or absence of the input signal on the input.