摘要 |
A signal disconnection detection circuit has a first comparing unit for producing a signal disconnection recognition signal only when a level of the first input signal is smaller than a first threshold value; a second comparing unit for producing an incomming signal only when a level of a second input signal is larger than a second threshold value; and a counter that receives the outputs of the first and second comparing unit and starts counting up when the first comparing unit produces the signal disconnection recognition signal, determining the possibility of the signal disconnection. The counter resets the counted value and stops its operation, determining that a reception signal is not disconnected, when the second comparing unit produces the reception signal. The counter produces the signal disconnection detection signal, determining that the signal is actually disconnected, when the second comparing unit produces no incomming signal before completion of the counting up.
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