Signal transmission circuit, signal transmission system, and signal transmission method

Patent metadata

Field	Value
Publication number	US-9160403-B2
Application number	US-201313888031-A
Country	US
Kind code	B2
Filing date	May 6, 2013
Priority date	Jun 26, 2012
Publication date	Oct 13, 2015
Grant date	Oct 13, 2015

Abstract

A signal transmission circuit includes a driver circuit that includes complementary inverters, each of the complementary inverters including a plurality of transistor switches, each of the plurality of transistor switches including a pair of transistors, one of the pair of transistors operating in a saturation region and another of the pair of transistors operating in a triode region to cause a certain impedance, and that drives each of the plurality of transistor switches in accordance with complementary signals so as to output complementary voltages to a transmission line; and first voltage sources that supply operating voltages to the driver circuit so as to adjust amplitudes of the complementary voltages output from the driver circuit to the transmission line.

First claim

What is claimed is:

1. A signal transmission circuit, comprising:
a driver circuit that includes complementary inverters, each of the complementary inverters including a plurality of transistor switches, each of the plurality of transistor switches including a pair of transistors, one of the pair of transistors operating in a saturation region and another of the pair of transistors operating in a triode region to cause a certain impedance, and that drives each of the plurality of transistor switches in accordance with complementary signals so as to output complementary voltages to a transmission line;
first voltage sources that supply operating voltages to the driver circuit so as to adjust amplitudes of the complementary voltages output from the driver circuit to the transmission line;
pre-drivers that output, to the driver circuit, complementary driving voltages for driving each of the plurality of transistor switches in accordance with the complementary signals;
second voltage sources that supply operating voltages to the pre-drivers, the operating voltages being adjusted such that each of the plurality of transistor switches is driven in accordance with the complementary driving voltages so as to cause an impedance corresponding to a characteristic impedance of the transmission line; and
a voltage adjustment unit that adjusts the operating voltages output by the second voltage sources, in accordance with the operating voltages output by the first voltage sources.

2. The signal transmission circuit according to claim 1 , wherein the voltage adjustment unit comprises:
a replica circuit of the driver circuit, the replica circuit including switches that correspond to the plurality of transistor switches;
third voltage sources that output, to the replica circuit, driving voltages for driving each of the switches; and
an adjustment unit that adjusts the driving voltages output by the third voltage sources such that voltages output by the replica circuit allow an impedance of the replica circuit to match an impedance corresponding to the characteristic impedance of the transmission line, and
wherein the operating voltages output by the second voltage sources are adjusted in accordance with the driving voltages output by the third voltage sources and adjusted by the adjustment unit.

3. The signal transmission circuit according to claim 2 , wherein the adjustment unit comprises:
comparator units that compare the voltages output by the replica circuit with reference voltages that are set in accordance with the operating voltages output by the first voltage sources; and
target voltage generation units that generate target voltages of the driving voltages output by the third voltage sources so as to make the voltages output by the replica circuit equal to the reference voltages.

4. The signal transmission circuit according to claim 2 , wherein the adjustment unit comprises:
a comparator unit that compares the voltages output by the replica circuit with each other, the voltages output by the replica circuit being complementary voltages; and
target voltage generation units that generate target voltages of the driving voltages output by the third voltage sources so as to decrease a difference between the complementary voltages output by the replica circuit.

5. A signal transmission system, comprising:
a transmission line; and
a signal transmission circuit comprising:
a driver circuit that includes complementary inverters, each of the complementary inverters including a plurality of transistor switches, each of the plurality of transistor switches including a pair of transistors, one of the pair of transistors operating in a saturation region and another of the pair of transistors operating in a triode region to cause a certain impedance, and that drives each of the plurality of transistor switches in accordance with complementary signals so as to output complementary voltages to the transmission line;
first voltage sources that supply operating voltages to the driver circuit so as to adjust amplitudes of the complementary voltages output from the driver circuit to the transmission line;
pre-drivers that output, to the driver circuit, complementary driving voltages for driving each of the plurality of transistor switches in accordance with the complementary signals;
second voltage sources that supply operating voltages to the pre-drivers, the operating voltages being adjusted such that each of the plurality of transistor switches is driven in accordance with the complementary driving voltages so as to cause an impedance corresponding to a characteristic impedance of the transmission line; and
a voltage adjustment unit that adjusts the operating voltages output by the second voltage sources, in accordance with the operating voltages output by the first voltage sources.

6. A signal transmission method, comprising:
adjusting, with a driver circuit, amplitudes of complementary voltages to be output to a transmission line from the driver circuit, in accordance with operating voltages supplied to the driver circuit from first voltage sources, the driver circuit including complementary inverters, each of the complementary inverters including a plurality of transistor switches, each of the plurality of transistor switches including a pair of transistors, one of the pair of transistors operating in a saturation region and another of the pair of transistors operating in a triode region to cause a certain impedance;
driving, with the driver circuit, each of the plurality of transistor switches of the driver circuit in accordance with complementary signals so as to output the complementary voltages to the transmission line;
outputting, with pre-drivers and to the driver circuit, complementary driving voltages for driving each of the plurality of transistor switches in accordance with the complementary signals;
supplying, with second voltage sources, operating voltages to the pre-drivers, the operating voltages being adjusted such that each of the plurality of transistor switches is driven in accordance with the complementary driving voltages so as to cause an impedance corresponding to a characteristic impedance of the transmission line; and
adjusting, with a voltage adjustment unit, the operating voltages output by the second voltage sources, in accordance with the operating voltages output by the first voltage sources.

Assignees

• Fujitsu Ltd

Inventors

• Suzuki Kosuke
• Tamura Hirotaka

Classifications

• H03K19/018514

  with at least one differential stage (H03K19/018528 and H03K19/018542 take precedence) · CPC title

• H04B3/02 Primary

  Details · CPC title