US 12,323,274 B2
Differential transmission substrate and power-over-differential data communication device
Yusuke Wachi, Tokyo (JP); and Takayasu Norimatsu, Tokyo (JP)
Assigned to Hitachi Astemo, Ltd., Hitachinaka (JP)
Appl. No. 18/561,655
Filed by Hitachi Astemo, Ltd., Hitachinaka (JP)
PCT Filed Feb. 2, 2022, PCT No. PCT/JP2022/004125
§ 371(c)(1), (2) Date Nov. 16, 2023,
PCT Pub. No. WO2022/244324, PCT Pub. Date Nov. 24, 2022.
Claims priority of application No. 2021-086247 (JP), filed on May 21, 2021.
Prior Publication US 2024/0235900 A1, Jul. 11, 2024
Int. Cl. H04L 25/02 (2006.01); H04B 3/14 (2006.01)
CPC H04L 25/0272 (2013.01) [H04B 3/146 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A differential transmission board that superimposes DC power on a differential data signal from a transmission/reception IC and then transmits the signal to a cable, the differential transmission board comprising:
a first differential transmission line including two wiring patterns;
a second differential transmission line including two wiring patterns;
two DC transmission lines that transmit the DC power;
two capacitor elements that cut off the DC power and pass only the differential data signal; and
two inductor elements that cut off a radio-frequency component that is the differential data signal and pass only a DC component,
wherein the first differential transmission line and the second differential transmission line are connected in series,
the two capacitor elements are connected in series to the second differential transmission line,
the second differential transmission line and the DC transmission line are connected via the two inductor elements, and
a characteristic impedance in a differential mode of the first differential transmission line and a characteristic impedance in the differential mode of the second differential transmission line are substantially equivalent, and a characteristic impedance in an in-phase mode of the second differential transmission line is higher than a characteristic impedance in the in-phase mode of the first differential transmission line.