Continuity/leakage tester for electronic circuits

• US 4,578,637 A
• Filed: 04/06/1984
• Issued: 03/25/1986
• Est. Priority Date: 04/06/1984
• Status: Expired due to Fees

• Current Assignee: Signetics Corporation
• Original Assignee: Signetics Corporation
• Inventors: Allen, Richard J., Youden, Richard W.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US06/597,772
• Time in Patent Office: 718 Days
• Field of Search: 324/51, 324/73 PC, 364/489, 364/490
• US Class Current: 324/538
• CPC Class Codes: G01R 31/2853 Electrical testing of internal connections or -isolation, e.g. latch-up or chip-to-lead connections G01R31/31717 takes precedence; test of chip-to-PCB or lead-to-PCB connections G01R31/66
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

A device for testing continuity and current leakage at leads of an electronic circuit such as an integrated circuit has a contact structure (16) having test terminals (T1-T28) for contacting the leads. A first and a second of the leads are power supply leads respectively contactable with a first and a second of the test terminals (T14 and T28 or T26). Continuity/leakage detection is done with one or more corresponding detection circuits (D1-D28). Each detection circuit has a channel along which both continuity and leakage are tested. A supply switching circuit (26) appropriately switches voltages between values suitable for continuity testing and values suitable for leakage testing.

Claims

1. A device for testing an electronic circuit having a set of electrical leads of which a first and a second are supply voltage leads, the device comprising:

contact means having test terminals for contacting the leads on a one-to-one basis, a first and a second of the test terminals respectively contactable with the first and second leads;

a supply point;

at least one detection circuit corresponding on a one-to-one basis to at least part of the test terminals, each detection circuit comprising;

a resistor coupled between the supply point and the corresponding test terminal; and

comparing means having a first input terminal coupled to the corresponding test terminal for receiving an input voltage, a second input terminal at a reference voltage V_TR, and an output terminal for providing an output signal at one of a pair of opposite states depending on whether the input and reference voltages are in a specified relationship; and

supply switching means for providing the first test terminal with a first test supply voltage V_TA, for providing the supply point with a detection supply voltage V_TX, and for switching the supply voltages between values suitable for testing continuity at the leads and values suitable for testing current leakage from at least one selected one of the leads to the first lead.

2. A device as in claim 1 wherein continuity at each selected lead is characterized by current flow between that selected lead and the first lead, the direction of this current flow being opposite to the direction of leakage current flowing between the first lead and that selected lead.

3. A device as in claim 2 wherein the direction of current flow through each resistor switches in switching between continuity testing and current leakage testing.

4. A device as in claim 1 wherein the supply switching means provides the second test terminal with a second test supply voltage V_TB for testing current leakage from at least one selected one of the leads to the second lead.

5. A device as in claim 4 wherein each selected lead is not one of the supply voltage leads.

6. A device as in claim 4 wherein one of the states of the output signal of the comparing means in each detection circuit represents presence of continuity or lack of current leakage beyond a specified level at the corresponding lead and the other state respectively represents absence of continuity or existence of current leakage beyond the specified level at the corresponding lead.

7. A device as in claim 6 wherein each detection circuit includes a display element for visually indicating the state of the output signal of the comparing means in that detection circuit.

8. A device as in claim 7 wherein each display element comprises a light-emitting diode.

9. A device as in claim 1 wherein the supply switching means switches the supply voltages (1) between first-type continuity-test values in which V_TA -V_SP -V_TX >

V_TR -V_TX >

0 for each detection means and first-type leakage-test values in which V_TA >

V_TR >

V_TX for each detection means or (2) second-type continuity-test values in which V_TA -V_SP -V_TX >

V_TR -V_TX >

0 for each detection means and second-type leakage-type values in which V_TA >

V_TR >

V_TX for each detection means, where V_SP is a specified voltage depending on the characteristics of the electronic circuit.

10. A device as in claim 9 wherein the supply switching means provides the second test terminal with a second test supply voltage V_TB at a value between V_TA and V_TR for testing current leakage from at least one selected one of the leads to the second lead.

11. A device as in claim 10 wherein the supply switching means switches the second test terminal to an open circuit position for continuity testing.