US3702967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic test system operable in two modes
Assignee: American Microsystems Holding Corp
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Filing: 1971-05-10
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Granted: 1972-11-14
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Expires: 1991-05-10
Abstract
Abstract A parametric test system that will provide a forcing current at a predetermined level in one mode or a forcing voltage of a constant potential in another mode, particularly adapted for testing semiconductor devices. The circuit comprises a first amplifier means or voltage compliance amplifier which is an amplifier that produces the voltage compliance necessary for high voltage drive and measurement. The output of this compliance amplifier is controlled by a second amplifier means or control amplifier, both amplifiers being connected between current sources operating at negative and positive voltage levels, and this output is connected to one of two test terminals adapted for connection to the junction of a device under test. The control amplifier is ''''floating'''' in that it is referenced to one test terminal so that in the current forcing mode it produces an output that keeps driving the compliance amplifier to a different voltage level which in turn increases current flow at the test terminals. When current through the test junction reaches the predetermined level, set by means of an adjustable resistor, the control amplifier provides the proper output and the system stabilizes, with the first amplifier means maintaining the compliance voltage required. For voltage forcing, an external power source supplies voltage via the control amplifier to one test terminal. As leakage current tries to flow through the junction of the device under test, the potential at the test terminals change and cause an imbalance at the inputs to the control amplifier which changes its output and keeps driving the compliance amplifier to a different voltage level, until it is sufficient to cause leakage current to flow through the device under test. A measuring resistor is provided in the output of the compliance amplifier to facilitate access to test values.
Inventors
- 👤 James H Mcphail
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:32
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/26; G01R31/2607
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
221 words
An electronic test system for forcing a constant current through a device under test comprising: a pair of test terminals adapted for connection to the junction terminals of a device under test, one of said terminals being connected to ground potential; first amplifier means for providing a compliance voltage having a pair of differential inputs and an output; an adjustable resistor connected between the output of said first amplifier means and said test terminal that is ungrounded; a first current source connected to said inputs of said first amplifier means; second amplifier means also having a pair of differential inputs, one of which is connected to said ungrounded test terminal, and an output connected to said first current source and one said input of said first amplifier means; a second current source connected to said second amplifier means; and means connected to the output of said first amplifier means for controlling the voltage supplied to said second amplifier means, thereby causing it to vary its output and in turn control the output of said first amplifier means; whereby when said adjustable resistor has been preset to a predetermined value, said system will stabilize automatically when said first amplifier means arrives at a point where it supplies the compliance voltage necessary to force the predetermined current level through the device under test.
Claim 2
Dependent Claim
221 words
An electronic test system for forcing a constant current through a device under test comprising: a pair of test terminals adapted for connection to the junction terminals of a device under test, one of said terminals being connected to ground potential; first amplifier means for providing a compliance voltage having a pair of differential inputs and an output; an adjustable resistor connected between the output of said first amplifier means and said test terminal that is ungrounded; a first current source connected to said inputs of said first amplifier means; second amplifier means also having a pair of differential inputs, one of which is connected to said ungrounded test terminal, and an output connected to said first current source and one said input of said first amplifier means; a second current source connected to said second amplifier means; and means connected to the output of said first amplifier means for controlling the voltage supplied to said second amplifier means, thereby causing it to vary its output and in turn control the output of said first amplifier means; whereby when said adjustable resistor has been preset to a predetermined value, said system will stabilize automatically when said first amplifier means arrives at a point where it supplies the compliance voltage necessary to force the predetermined current level through the device under test.
Claim 3
Dependent Claim
176 words
An electronic test system for providing and maintaining a highly accurate source of current and voltage at preselected levels to devices under test, said system comprising: output terminal means adapted for connection to a device under test; means for supplying a predetermined, selectable output current, said current supply means including a first control amplifier means having its input connected to one of said output terminals; a second amplifier means having its input electrically engaged to the output of said control amplifier, said first and second amplifier means being so connected that the system is in equilibrium when the output of said second amplifier means is grounded; current adjusting means interconnecting the output of said second amplifier means and the input to said first amplifier means; means for supplying a predetermined, selectable output voltage; and switch means connected to said current supply means, said voltage supply means, and said output terminal means such that either said output voltage or said output current is impressed upon said output terminal means and thereby supplied to said device under test.
Claim 4
Dependent Claim
176 words
An electronic test system for providing and maintaining a highly accurate source of current and voltage at preselected levels to devices under test, said system comprising: output terminal means adapted for connection to a device under test; means for supplying a predetermined, selectable output current, said current supply means including a first control amplifier means having its input connected to one of said output terminals; a second amplifier means having its input electrically engaged to the output of said control amplifier, said first and second amplifier means being so connected that the system is in equilibrium when the output of said second amplifier means is grounded; current adjusting means interconnecting the output of said second amplifier means and the input to said first amplifier means; means for supplying a predetermined, selectable output voltage; and switch means connected to said current supply means, said voltage supply means, and said output terminal means such that either said output voltage or said output current is impressed upon said output terminal means and thereby supplied to said device under test.
Claim 5
Dependent Claim
43 words
The system of claim 2 further characterized by: means for limiting the output voltage of said second amplifier means, said limiting means connected to the input to said second amplifier means and adapted to maintain the voltage supplied thereto below a predetermined level.
Claim 6
Dependent Claim
32 words
The system of claim 3 further characterized by: connector means interconnecting said output terminal and said control amplifier means so that Said amplifier is referenced to the voltage on said output terminal.
Claim 7
Dependent Claim
35 words
The system of claim 4 wherein said output means comprises: a pair of terminals, one of which is connected to said current adjusting means and the other is grounded; and switching means interconnecting said terminals.
Claim 8
Dependent Claim
14 words
The system of claim 5 wherein said current control means comprises a variable resistor.
Claim 9
Dependent Claim
13 words
The system of claim 6 wherein said limiting means comprises a zener diode.
Claim 10
Dependent Claim
146 words
An electronic test system for providing and maintaining a highly accurate source of current and voltage at preselected levels to devices under test, said system comprising: output terminal means adapted for connection to a device under test; a current source for supplying a predetermined, selectable output current; means for supplying a predetermined, selectable output current; means for supplying a predetermined, selectable output voltage including a control amplifier; a compliance amplifier providing voltage at a predetermined compliance level; feedback means interconnecting the output of said compliance amplifier with the input of said control amplifier such that the amplifier pair is stable; means connecting the output of said compliance amplifier to said output terminal means; and an outside voltage source connected to the input of said control amplifier such that the voltage supplied to the input of said outside voltage source also appears at said output terminal means.
Claim 11
Dependent Claim
146 words
An electronic test system for providing and maintaining a highly accurate source of current and voltage at preselected levels to devices under test, said system comprising: output terminal means adapted for connection to a device under test; a current source for supplying a predetermined, selectable output current; means for supplying a predetermined, selectable output current; means for supplying a predetermined, selectable output voltage including a control amplifier; a compliance amplifier providing voltage at a predetermined compliance level; feedback means interconnecting the output of said compliance amplifier with the input of said control amplifier such that the amplifier pair is stable; means connecting the output of said compliance amplifier to said output terminal means; and an outside voltage source connected to the input of said control amplifier such that the voltage supplied to the input of said outside voltage source also appears at said output terminal means.
Claim 12
Dependent Claim
41 words
The system of claim 8 further characterized by means for limiting the output voltage of said compliance amplifier, said means being connected to the input of said compliance amplifier and adapted to maintain the voltage supplied thereto below a predetermined level.
Claim 13
Dependent Claim
22 words
The system of claim 9 further characterized by information output terminals from which leakage currents and breakdown voltages may be directly measured.
Claim 14
Dependent Claim
148 words
An electronic test system for providing a highly accurate source of current and voltage at preselected levels to devices under test, said system comprising: a control amplifier having inverting and non-inverting inputs and an output; a compliance amplifier having inverting and non-inverting inputs and an output; feedback means connecting the output of said compliance amplifier with the inverting input of said control amplifier; means interconnecting the output of said control amplifier to the non-inverting input of said compliance amplifier; a first switching means for connecting said device under test to either the inverting or non-inverting input of said control amplifier; current control means interconnecting the output of said compliance amplifier and said device under test; a second switching means connected in series with said feedback means for opening or closing said feedback path; and means for impressing a variable voltage on the non-inverting input of said control amplifier.
Claim 15
Dependent Claim
148 words
An electronic test system for providing a highly accurate source of current and voltage at preselected levels to devices under test, said system comprising: a control amplifier having inverting and non-inverting inputs and an output; a compliance amplifier having inverting and non-inverting inputs and an output; feedback means connecting the output of said compliance amplifier with the inverting input of said control amplifier; means interconnecting the output of said control amplifier to the non-inverting input of said compliance amplifier; a first switching means for connecting said device under test to either the inverting or non-inverting input of said control amplifier; current control means interconnecting the output of said compliance amplifier and said device under test; a second switching means connected in series with said feedback means for opening or closing said feedback path; and means for impressing a variable voltage on the non-inverting input of said control amplifier.
Claim 16
Dependent Claim
57 words
The system of claim 11 further characterized by a negative current source connected through a first zener diode to the inverting input of compliance amplifier and through a resistor to the non-inverting input of said compliance amplifier; and a positive source of current connected through a second zener diode to the non-inverting input of said control amplifier.
Claim 17
Dependent Claim
22 words
The system of claim 12 further characterized by means for limiting the output voltage of said compliance amplifier to a predetermined value.
Claim 18
Dependent Claim
24 words
The system of claim 13 wherein said limiting means comprises a zener diode connected between ground and the non-inverting input of said compliance amplifier.
Claim 19
Dependent Claim
53 words
The system of claim 14 further characterized by output means comprising a pair of terminals for electrical connection to said device under test, one of said terminals being grounded, the other being connected to said current control means, and switching means interconnecting said terminals for shorting them together when said switch is closed.
Claim 20
Dependent Claim
14 words
The sYstem of claim 15 wherein said current control device comprises a variable resistor.
Claim 21
Dependent Claim
13 words
The system of claim 16 wherein said feedback means is a zener diode.
Claim 22
Dependent Claim
22 words
The system of claim 17 further characterized by connector means interconnecting the output of said compliance amplifier and the inverting input thereto.
Claim 23
Dependent Claim
34 words
The system of claim 18 further characterized by a fourth switching means interconnecting the non-grounded output terminal and said control amplifier such that said control amplifier is floating when said switch means is closed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-14 | 1976-05-15 | 1976-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-14 | 1980-05-15 | 1980-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-14 | 1984-05-15 | 1984-11-14 | $7700.00 | Window Closed / Lapsed |