SIGNAL TRANSMISSION CIRCUIT

摘要

A signal transmission circuit includes a transceiver, an impedance adjustment circuit, a first control circuit and a second control circuit. The impedance adjustment circuit realizes a low impedance state and a normal state of the transmission line. The first control circuit controls the impedance adjustment circuit to realize the low impedance state for a fixed period that is shorter than a width of one bit, when a change of a signal level on the transmission line is detected. The second control circuit controls the impedance adjustment circuit according to a transmission data transmitted from the transceiver, when detecting that a communication frame wins an arbitration by comparing the transmission data and the received data, to realize the low impedance state in an entire period where the signal level on the transmission line is recessive until transmission of the communication frame ends.

主权项

1. A signal transmission circuit connected to a transmission line that includes a pair of signal lines and transmits a differential signal changing between binary levels of recessive and dominant, the signal transmission circuit comprising:
a transceiver that encodes a transmission data, transmits the transmission data to the transmission line, and decodes a signal received from the transmission line to generate a received data; an impedance adjustment circuit that realizes a low impedance state of the transmission line by connecting a resistance component between the pair of signal lines and a normal state of the transmission line by disconnecting the resistance component; a first control circuit that controls the impedance adjustment circuit to realize the low impedance state for a fixed period that is shorter than a width of one bit, when a change of a signal level on the transmission line is detected; and a second control circuit that controls the impedance adjustment circuit according to the transmission data, when detecting that a communication frame wins an arbitration by comparing the transmission data and the received data, to realize the low impedance state in an entire period where a signal level on the transmission line is recessive until transmission of the communication frame winning the arbitration ends.