Patent attributes
Surge protection circuitry includes a pair of series connected diodes sharing a first common terminal that is directly electrically connected to only one of a pair of transmission lines, a pair of series connected Zener diodes, in parallel with the series connected diodes, sharing a second common terminal that is directly electrically connected to only the other of the transmission lines, and a pair of series connected power supplies each configured to reverse bias one of the series connected diodes such that the diodes prevent electrical coupling of the Zener diodes to the transmission lines responsive to a voltage of the signal source being less than a threshold value, and the diodes permit electrical coupling of at least one of the Zener diodes to the transmission lines responsive to the voltage being greater than the threshold value.
