SIGNAL TRANSMISSION CIRCUIT, SEMICONDUCTOR INTEGRATED CIRCUIT, AND SIGNAL TRANSMISSION CIRCUIT ADJUSTMENT METHOD

摘要

A transmission circuit is formed such that plural driver units of each driver circuit are connected together in parallel. A code setting section detects a voltage Vms output from a replica circuit corresponding to a driver unit of a driver circuit, and detects a voltage Vmo output from a replica circuit corresponding to one driver unit of the driver circuit, and based on a ratio of the voltages Vms, Vmo, sets operation numbers Na to Nd of driver units for each of the driver circuits such that the output resistance value of each of the driver circuits becomes pre-set output resistance values Roa to Rod. The driver circuit has a number of driver units according to the operation number connected together in parallel and operating.

主权项

1. A signal transmission circuit, comprising:
a plurality of driver circuits that each include a plurality of operation unit circuits formed so as to have a specific output resistance value and operating so as to output a voltage according to an input signal, an output resistance value of the operation unit circuits being set according to a pre-set output resistance value for each of the plurality of driver circuits, with an operation number of the operation unit circuits being connected together in parallel and operated, as a result of setting the operation number of the operation unit circuits, such that signals are output from the plurality of driver circuits with a voltage according to the input signal, and with the plurality of driver circuits being connected together in parallel such that the output signals are combined together; an individual detection section that includes replica circuits provided so as to correspond to at least two driver circuits out of the plurality of driver circuits and having resistance values corresponding to the output resistance value of one of the operation unit circuits, and that detects an output voltage of each of the replica circuits; and a setting section that, based on a voltage ratio between an output voltage of a replica circuit corresponding to one driver circuit out of the at least two driver circuits detected by the individual detection section and an output voltage of a replica circuit corresponding to another driver circuit out of the at least two driver circuits, computes a ratio for at least one of the driver circuits based on the output resistance value of each of the plurality of driver circuits, and sets an operation number of operation unit circuits to operate in each of the plurality of driver circuits from the ratio based on the output resistance value computed for the at least one of the driver circuits and from a ratio based on the pre-set output resistance values for the plurality of driver circuits, such that the output resistance value of each of the plurality of driver circuits becomes the pre-set output resistance value.