US 11,703,549 B2
Systems and methods for ground fault detection
Sunny Bagga, Corona, CA (US); Brian J. Cadwell, Pasadena, CA (US); and Shaun Mark Goodwin, East New Market, MD (US)
Assigned to NORTHROP GRUMMAN SYSTEMS CORPORATION, Falls Church, VA (US)
Filed by Sunny Bagga, Corona, CA (US); Brian J. Cadwell, Pasadena, CA (US); and Shaun Mark Goodwin, East New Market, MD (US)
Filed on Apr. 30, 2020, as Appl. No. 16/863,308.
Prior Publication US 2021/0341547 A1, Nov. 4, 2021
Int. Cl. G01R 31/52 (2020.01); G01R 31/28 (2006.01); G01R 31/3193 (2006.01); H02H 3/32 (2006.01); H02H 3/16 (2006.01); G01R 31/319 (2006.01); G01R 31/08 (2020.01)
CPC G01R 31/52 (2020.01) [G01R 31/083 (2013.01); G01R 31/2834 (2013.01); G01R 31/31905 (2013.01); G01R 31/31932 (2013.01); H02H 3/16 (2013.01); H02H 3/32 (2013.01)] 19 Claims
OG exemplary drawing
 
2. A ground fault detection circuit comprising:
a band-pass filter comprising a first node and a second node, the first node being coupled to a local ground of a test head of an automatic test equipment (ATE) system for an electrical device that is coupled via at least one wire to a test instrument of the ATE, the second node being coupled to an earth ground, the band-pass filter being configured to pass and amplify a test current signal established at the first node in response to one of a coupling of a conductor of the at least one wire carrying the test current signal to the local ground, and a coupling of a conductive element of the electrical device carrying the test current signal to the local ground; and
a comparator circuit configured to compare an amplified test current signal to a voltage threshold and output a fault alert signal to provide an indication of a ground fault based on the comparison, wherein the band-pass filter comprises a first amplification and filtering stage and a second amplification and filtering stage,
the first amplification and filtering stage comprising:
a first input stage;
a first feedback stage; and
a first amplifier, wherein the first amplification and filtering stage is configured to pass and amplify test current signals within a first frequency range, and the first amplification and filtering stage is coupled to the first input node and the second input node;
the second amplification and filtering stage comprising:
a second input stage;
a second feedback stage; and
a second amplifier, wherein the second amplification and filtering stage is configured to pass and amplify test current signals within a second frequency range, and the second amplification and filtering stage is coupled to an output of the first amplification and filtering stage, the second input node, and an input of the comparator circuit.