公开(公告)号：US20180045537A1

公开(公告)日：2018-02-15

申请号：US15668825

申请日：2017-08-04

Applicant: CHROMA ATE INC.

Inventor： Tsz-Lang CHEN ,  Ming-Chieh LIN ,  Yen-Ching LIU

IPC: G01D5/16

Abstract: A contact detection circuit is applied to a four-terminal measurement device. The contact detection circuit comprises a first isolator, a signal generator, a multiplier and a calculator. The first isolator comprises a primary side and a secondary side, with the secondary side comprising a first terminal and a second terminal, with the first terminal configured to be electrically connected to a driving terminal and the second terminal configured to be electrically connected to a measuring terminal. The signal generator is configured to provide a measuring signal. The multiplier is configured to generate an output signal based on the measuring signal and a first reflected signal when the first reflected signal is induced at the primary side of the first isolator based on the measuring signal. The calculator calculates contact resistance between the driving terminal and the measuring terminal based on a direct-current component of the output signal.