US 8,786,291 B2 · In-situ cable unplug detector operating during normal signaling mode

Abstract

An in-situ unplug detector circuit detects when a cable is disconnected or unplugged. Detection does not have to wait for normal signaling to pause, such at the end of a frame or timeout. Instead, detection occurs during normal signaling. When the cable is disconnected, the transmitter no longer drives the load at the far end of the cable, and thus can drive the near end to a higher high voltage and to a lower low voltage. The increased voltage swing is detected by a detector at the near end that amplifies the transmitter output to the cable. A fast detector has a higher bandwidth and faster response time than a slow detector, and generates a fast detect signal that crosses over a slow detect signal. When the cable is disconnected, the fast detect signal again crosses over the slow detect signal, and decision logic activates an unplug signal.

Claims20

Dependent claims

An in-situ cable disconnect detector comprising:

a fast detector, coupled to a near-end transmitter output that connects to a far-end receiver through a cable, the fast detector amplifying the near-end transmitter output to generate a fast detect signal;
a slow detector, coupled to the near-end transmitter output, for amplifying the near-end transmitter output to generate a slow detect signal;
wherein the fast detect signal changes more rapidly than the slow detect signal in response to changes in the near-end transmitter output;
and
decision logic, receiving the fast detect signal and the slow detect signal, the decision logic generating an unplug detected signal when the fast detect signal crosses over the slow detect signal for a second time after a transition of the near-end transmitter output,
whereby a cable disconnect is detected by a second crossover of the fast detect signal over the slow detect signal.

3 more elements

An in-situ unplug detector comprising:

line driver means for driving current onto a near end of a communications line to generate voltage swings in response to user data for transmission over the communications line;
fast detector means, connected to the near end of the communications line, for generating a fast signal in response to the voltage swings;
slow detector means, connected to the near end of the communications line, for generating a slow signal in response to the voltage swings;
wherein the fast signal is generated more rapidly than the slow signal;
and
decision means, receiving the fast signal and receiving the slow signal, for generating an unplug detected signal when the fast signal crosses above the slow signal for a second time after a transition of the voltage swings,
whereby the unplug detected signal is generated during transmission of the user data.

4 more elements

Dependencies are inferred from the claim text.

In-situ cable unplug detector operating during normal signaling mode

Life of this patent

In-situ cable unplug detector operating during normal signaling mode

Life of this patent

Abstract

Claims20