Patent ID: 7812625

Claim:
A circuit in a probe card comprising a signal line coupled between a test unit and a plurality of chips to be tested for transmitting a plurality of test response signals from the plurality of chips to the test unit, and a plurality of detection probes respectively coupled to the signal line for receiving the test response signals, wherein the improvement comprises: a plurality of switch modules electrically connected to the signal line and the chips to be tested so as to selectively transmit the test response signals from the chips to the test unit through the signal line, each of the switch modules having a first end and a second end, the first end coupled to the test unit through the signal line, the second end coupled to the corresponding chip through the corresponding detection probe, each of the switch modules transmitting the corresponding test response signal from the corresponding chip to the test unit, and each of the switch modules determining whether to float the detection probe coupled to the corresponding switch module according to a status of a test power such that the chips are able to be tested without disruption caused by an electrical short.