Automatic circuit tester with separate instrument and scanner buses

• US 5,101,150 A
• Filed: 02/22/1991
• Issued: 03/31/1992
• Est. Priority Date: 02/22/1991
• Status: Expired due to Term

• Current Assignee: Genrad Incorporated (Teradyne Incorporated)
• Original Assignee: Genrad Incorporated (Teradyne Incorporated)
• Inventors: Sargent, Brian J., Pietrantoni, Rudy D., Pincus, Robert H., Sullivan, Robert C.
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): BURNS, WILLIAM
• Application Number:
  US07/660,289
• Time in Patent Office: 403 Days
• Field of Search: 324/158 F, 324/72.5, 324/73.1, 371/22.1, 371/15.1, 371/116.1, 361/412, 361/413, 361/415
• US Class Current: 714/724
• CPC Class Codes: G01R 31/2834 Automated test systems [ATE]; using microprocessors or computers G01R31/317 takes precedence; ATE for detection of defective computer hardware G06F11/2736
• CPC Class Codes: G01R 31/2851 Testing of integrated circuits [IC] G01R31/317 takes precedence; testing individual devices G01R31/26; testing printed circuits G01R31/2801
• CPC Class Codes: G01R 31/31905 Interface with the device under test [DUT], e.g. arrangements between the test head and the DUT, mechanical aspects, fixture
• CPC Class Codes: G01R 31/31907 Modular tester, e.g. controlling and coordinating instruments in a bus based architecture
• CPC Class Codes: G01R 31/31926 Routing signals to or from the device under test [DUT], e.g. switch matrix, pin multiplexing

Abstract

An automatic circuit tester (10) employs a scanner (20) embodied in a group of interconnected scanner boards (46, 47) that provide switching by means of mechanical relays. The scanner boards plug simultaneously into respective instrument boards (44) and into a common scanner bus (50) separate from an instrument bus (38) that carries the signals that control the instruments on the instrument boards (44). The scanner bus provides a common pathway for signals to travel between instruments or system pins to which one scanner board is connected and those to which another is connected. It also provides scanner-control paths so that the instrument boards to which the scanner boards are connected to not need to provide such paths and thus do not need to be custom-designed for the particular tester in which they are used.

Claims

1. An automatic circuit tester comprising:

A) tester control circuitry for generating instrument- and scanner-control signals for controlling the states of instruments and scanners, respectively;

B) a fixture, adapted for connection of system pins thereto and for reception of a device under test thereon, for coupling the system pins to predetermined test points on the device under test;

C) a common backplane instrument bus connected to receive the instrument-control signals and including control conduction paths for conducting the instrument-control signals therealong;

D) a plurality of instrument boards, each of which contains an electronic instrument controllable by instrument-control signals introduced at one, control edge of the instrument board and providing at another, scanner edge of the instrument board an instrument port at which the instrument board is connected at the control edge thereof to the instrument bus to receive the instrument-control signals therefrom for control of its respective instrument;

E) a plurality of scanner boards, each of which provides system pins on a fixture edge thereof connected to the fixture and further provides at least one instrument port on a separate instrument edge thereof connected to the scanner edge of a respective one of the instrument boards for electrical communication between the instrument ports of the scanner board and its respective instrument board, each scanner board further containing scanner switches connected selectively to perform coupling and uncoupling between the instrument ports and the system pins, each scanner board further containing switch-control circuits for controlling the states of the scanner switches in response to scanner-control signals applied thereto; and

F) a separate scanner backplane bus into which each scanner board is connected for application of the scanner-control signals to the switch-control circuits thereon.

2. An automatic circuit tester as defined in claim 1 wherein:

A) the scanner bus additionally includes signal conduction paths, separate from the control conduction paths, for conducting instrument signals therealong;

B) at least one of the scanner boards includes a switch thereon so connected as selectively to couple and uncouple an instrument port thereof to and from a signal conduction path on the scanner bus; and

C) at least one other scanner board includes a switch thereon so connected as selectively to couple and uncouple a system pin thereof to and from the signal conduction path on the scanner bus,

whereby an instrument connected to the one scanner board can be coupled to a system pin on the other scanner board.

3. An automatic circuit tester comprising:

A) tester control circuitry for generating instrument-control signals for controlling the states of instruments;

B) a fixture, adapted for connection of system pins thereto and for reception of a device under test thereon, for coupling the system pins to predetermined test points on the device under test;

C) a common backplane instrument bus connected to receive the instrument-control signals and including control conduction paths for conducting the instrument-control signals therealong;

D) a plurality of instrument boards, each of which contains an electronic instrument controllable by instrument-control signals introduced at one, control edge of the instrument board and providing at another, scanner edge of the instrument board an instrument port at which the instrument drives and/or senses signals under control of the instrument-control signals, each instrument board being connected at the control edge thereof to the instrument bus to receive the instrument-control signals therefrom for control of its respective instrument;

E) a separate scanner backplane bus providing signal conduction paths for conducting instrument signals therealong; and

F) a plurality of scanner boards, each of which is connected to the scanner bus, provides system pins on a fixture edge thereof connected to the fixture, and further provides at least one instrument port on a separate instrument edge thereof connected to the scanner edge of a respective one of the instrument boards for electrical communication between the instrument ports of the scanner board and its respective instrument board, each scanner board further containing scanner switches connected selectively to perform coupling and uncoupling between the instrument ports and the system pins, at least one of the scanner boards including a switch thereon so connected as selectively to couple and uncouple an instrument port thereof to and from a signal conduction path on the scanner bus, at least one other scanner board including a switch thereon so connected as selectively to couple and uncouple a system pin thereof to and from the signal conduction path on the scanner bus.