A 6-Gb/s Inductively-Powered Non-Contact Connector With Rotatable Transmission Line Coupler and Interface Bridge IC

• Published in: IEEE journal of solid-state circuits 2022-02, Vol.57 (2), p.535-545
• Main Authors: Kosuge, Atsutake, Hamada, Mototsugu, Kuroda, Tadahiro
• Format: Article
• Language: English
• Subjects: Analog integrated circuits; Bandwidth; Bit error rate; Connectors; Couplers; Couplings; electromagnetic (EM) coupling; equalizers; High speed; Industrial robots; Integrated circuits; Interfaces; Manipulators; near field communication; On-Off Keying; Robot arms; Robots; Rotation; transceiver; Transmission lines; wireless power transmission
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2021.3108820

A 6 Gb/s 9.8 pJ/b rotatable non-contact connector applicable to industrial robot arms is developed. The proposed non-contact connector enables a high-speed and highly reliable wireless data connection between three-dimensional (3-D) cameras and an edge computer in an autonomously controlled robot. A rotatable transmission line coupler (RTLC) is proposed to accommodate the rotational operation of the robot arm. Since the proposed doughnut-shaped RTLC has a constant overlapped area at any rotation angle, the RTLC has a constant coupling gain at all rotation angles. To remove inter-symbol interference (ISI) occurring at a specific rotation angle, a pulse-equalizing receiver is also developed. An interface bridge IC is proposed to transfer a wide range of interface signals from a slow-control signal such as the control area network (CAN) to a high-speed video interface signal. A signal protocol conversion technique applying on-off keying (OOK) modulation is also developed in order to transfer slow legacy interfaces used in the robot arms that include a dc component. Experiments with a test chip fabricated in a 40 nm CMOS process confirmed that bit error rate (BER) was lower than 10 ^{-12} at any rotation angle in a communication distance of 3 mm. The proposed system improves energy efficiency by a factor of 3.7, area efficiency by a factor of 1.8.