US Patent No. 9,374,888

DIFFERENTIAL TRANSMISSION CIRCUIT HAVING AN INDUCTOR UNIT AND CAPACITOR UNITS CONFIGURED TO ATTENUATE A COMMON-MODE DIGITAL SIGNAL COMPONENT


Patent No. 9,374,888
Issue Date June 21, 2016
Title Differential Transmission Circuit Having An Inductor Unit And Capacitor Units Configured To Attenuate A Common-mode Digital Signal Component
Inventorship Daishiro Sekijima, Tokyo (JP)
Assignee CANON KABUSHIKI KAISHA, Tokyo (JP)

Claim of US Patent No. 9,374,888

6. A printed circuit board comprising:
a printed wiring board;
a semiconductor element configured to be mounted on the printed wiring board, and configured to transmit a digital differential
signal;

a differential signal wiring configured to be formed on the printed wiring board, and configured to comprise a first signal
line and a second signal line connected to the semiconductor element;

an inductor unit configured to be formed on the printed circuit board, and configured to comprise a first inductor provided
on the first signal line and a second inductor provided on the second signal line;

an input side capacitor unit configured to comprise a first capacitor wherein one end thereof is connected to a signal input
end of the first inductor, and the other end thereof is connected to a signal input end of the second inductor, a second capacitor
wherein one end thereof is connected to the signal input end of the first inductor, and the other end thereof is connected
to a ground, and a third capacitor wherein one end thereof is connected to the signal input end of the second inductor, and
the other end thereof is connected to the ground; and

an output side capacitor unit configured to be provided between the inductor unit and a differential signal reception unit,
wherein a difference between the capacitances of the second capacitor and the third capacitor falls within 20%, and a value
of C1/C2, when a capacitance of the first capacitor is C1, and a capacitance of one of the second and the third capacitor
is C2, is equal to or more than 0.75 and equal to or less than 2.25.