Multi-level encoding for battery management system

A semiconductor device for encoding data bits onto a transmission line capable of reducing or eliminating undesired emission of radio frequency energy, comprising:

• a bidirectional transceiver;
• and
• a logic circuit constructed and arranged to encode data for output from the bidirectional transceiver as a serial data stream along the signal transmission path that is modulated over at least three discrete signal levels at a predetermined and fixed data pulse frequency, the logic circuit further configured to encode a plurality of at least three data units of the serial data stream into a data packet, the data packet including at least three symbols corresponding to the at least three data units, wherein the at least three symbols are constructed and arranged with at least four consecutive transmissions per symbol, each transmission assuming one of the three discrete signal levels;
• wherein the at least three symbols are encoded into a subset of a maximum number of possible combinations of the at least three discrete signal levels and stored in a data encoding table, and wherein the bidirectional transceiver is configured to discard combinations of the maximum number of possible combinations of the at least three discrete signal levels not stored in the data encoding table in order to reduce the undesired emission of radio frequency energy with respect to the symbols when output to the transmission line.

A method for encoding data bits onto a transmission line between a first battery cell controller and a second battery cell controller, comprising:

• configuring a circuit for three discrete signal levels;
• generating a plurality of data nibbles from the three discrete signal levels;
• encoding the data nibbles into three symbols, each symbol formed of four consecutive chips, each chip assuming one of the three discrete signal levels;
• encoding each symbol on two periods of a fixed data pulse frequency;
• and
• discarding any of a maximum number of possible combinations of the at least three discrete signal levels that reduce or eliminate a source of electromagnetic interference (EMI) on the transmission line.