Circuits and methods for protecting integrated circuits from powerline noise

A powerline communication system comprising:

• a CMOS-based differential transceiver having a low resistance coupling that includes a first port and a second port;
• a first diode and a second diode electrically connecting a reference voltage to each of the first port and the second port, respectively;
• a third diode and a fourth diode electrically connecting a power supply to each of the first port and the second port, respectively;
• a first zener diode and a second zener diode each electrically coupled between the power supply and the reference voltage and having a breakdown voltage greater than a voltage of the power supply;
• a transformer configured to step up a voltage difference applied by the differential transceiver across the first port and the second port from a first winding to a second winding, the second winding having a first end and a second end;
• a pair of zener diodes, comprising a third zener diode and a fourth zener diode, having (i) respective cathodes of the third zener diode and the fourth zener diode electrically coupled to one of the first end and the second end of the second winding and (ii) anodes of the third zener diode and the fourth zener diode electrically coupled together;
• and
• a pair of capacitors, each capacitor connected in series between a powerline and one of the first end and the second end of the second winding.

A method comprising:

• receiving a powerline signal from a powerline;
• low pass filtering the powerline signal, said low pass filtering comprising receiving the powerline signal on a first winding of a transformer, wherein the first winding of the transformer is electrically coupled to a pair of zener diodes that include a first zener diode and a second zener diode;
• high pass filtering the powerline signal, said high pass filtering comprising transmitting the powerline signal onto a second winding of the transformer, wherein the second winding of the transformer is electrically coupled to a power supply through a first diode and to a reference voltage through a second diode, wherein the first diode and second diode define a maximum voltage range of the powerline signal;
• via a low resistance coupling, receiving the powerline signal in a CMOS-based integrated circuit after said high pass filtering;
• transmitting a signal from the integrated circuit;
• high pass filtering the transmitted signal using the first diode and second diode;
• and
• low pass filtering the transmitted signal using the first and second zener diodes of the pair of zener diodes.