Voltage fault detection and protection

Abstract

A fault detection and protection circuit can include a comparing circuit (e.g., a comparator or a detector) that can be connected to a power line supplying power to an electronic device being tested. The comparing circuit can be configured to detect a fault in which the power line is shorted to ground. For example, the electronic device being tested may have a fault in which its power terminals are shorted to ground. Upon detection of such a fault, the comparing circuit activates one or more switches that shunt capacitors or other energy storage devices on the power line to ground. The comparing circuit may alternatively or in addition activate one or more switches that disconnect the power supply supplying power to the electronic device under test from probes contacting the electronic device.

1 . A method of detecting and responding to a fault in a semiconductor device under test, the method comprising:
 monitoring at least one electrical characteristic of a power line electrically connected to the semiconductor device under test for indications of the fault;   determining from the at least one electrical characteristic whether a fault condition exists; and   in response to determining the fault condition exists, diverting power from a probe in electrical connection with a terminal of the semiconductor device under test affected by the fault, wherein the diverting occurs in close proximity to the probe in relation to a power supply supplying power to the power line.   
   
   
       2 . The method of  claim 1  further comprising providing a capacitor electrically connected to the power line. 
   
   
       3 . The method of  claim 2 , wherein the diverting comprises at least one of disconnecting the probe from the capacitor, disconnecting the probe from the power supply, or connecting the probe to ground. 
   
   
       4 . The method of  claim 3 , wherein the diverting comprises disconnecting the probe from the capacitor. 
   
   
       5 . The method of  claim 3 , wherein the diverting comprises disconnecting the probe from the power supply. 
   
   
       6 . The method of  claim 3 , wherein the diverting comprises disconnecting the probe from the capacitor and disconnecting the probe from the power supply. 
   
   
       7 . The method of  claim 3 , wherein the diverting comprises connecting the probe to ground. 
   
   
       8 . The method of  claim 3 , wherein:
 the probe is one of a plurality of probes of a probe card assembly configured to contact a plurality of terminals of the semiconductor device, and   the monitoring comprises monitoring a portion of the power line disposed on the probe card assembly.   
   
   
       9 . The method of  claim 8 , wherein the determining comprises comparing a voltage on the power line to a reference voltage. 
   
   
       10 . The method of  claim 9 , wherein the fault is a short to ground. 
   
   
       11 . The method of  claim 1  further comprising testing the electronic device. 
   
   
       12 . The method of  claim 1 , wherein the monitoring comprising monitoring a voltage on the power line. 
   
   
       13 . The method of  claim 1 , wherein the power supply is connected to a first end of the power line and the probe is connected to a second end of the power line, and the monitoring comprises monitoring a voltage on the power line at a location on the power line that is in close proximity to the probe relative to the power supply. 
   
   
       14 . The method of  claim 1 , wherein the monitoring comprises monitoring the at least one electrical characteristic at a plurality of locations on a power plane, wherein the power plane is electrically connected through the power line to a power supply, and a plurality of probes are electrically connected to the power plane and disposed to contact a plurality of terminals of a plurality of electronic devices. 
   
   
       15 . The method of  claim 14 , wherein the monitoring further comprises determining whether a difference in voltages between at least one pair of locations on the power plane exceeds a predetermined threshold. 
   
   
       16 - 44 . (canceled)