Impulse voltage generator circuit

• US 6,211,683 B1
• Filed: 03/16/1999
• Issued: 04/03/2001
• Est. Priority Date: 09/23/1996
• Status: Expired due to Term

• Current Assignee: Haefely Test AG (Hubbell, Inc.)
• Original Assignee: Trench Switzerland AG (Trench Group GmbH)
• Inventors: Wolf, Jurgen
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): Deb, Anjan K
• Application Number:
  US09/254,913
• Time in Patent Office: 749 Days
• Field of Search: 324/548, 324/76.34, 307/110, 307/108, 333/20
• US Class Current: 324/548
• CPC Class Codes: G01R 31/14 Circuits therefor , e.g. for generating test voltages, sensing circuits G01R31/1209 - G01R31/1227 take precedence; for testing switches G01R31/327
• CPC Class Codes: G01R 31/2841 Signal generators
• CPC Class Codes: G01R 31/64 Testing of capacitors
• CPC Class Codes: H03K 3/537 the switching device being a spark gap

Abstract

A pulsed-voltage generator circuit for producing a flash pulsed voltage for testing the capacitance of a unit under test has two stages (1, 2) which can be charged. Each stage (1, 2) comprises, connected in series, a surge capacitance (11, 21) and a switching spark gap (12, 22), a parallel resistor (13, 23) connected in parallel with the surge capacitance (11, 21) and the switching spark gap (12, 22), and, connected in series with them, a series resistor (14, 24). The two stages (1, 2) are connected to one another such that they can be charged connected in parallel and can be discharged connected in series. A load capacitance (4) is connected to the second stage (2), an additional circuit element (5) for reducing the overshoot of the pulse fronts of the flash pulsed voltage for the load capacitance (4) being arranged between the second stage (2) and the load capacitance (4). The additional circuit element (5) has a compensation capacitance (51) and, connected in parallel with it, a discharge resistor (52).

Claims

1. A pulsed-voltage generator circuit for producing a flash pulsed voltage for testing the capacitance of a unit under test, comprising:

at least one stage (1,2) which can be charged, said at least one stage (1, 2) having a surge capacitance (11, 21) and a switching device connected in series, a parallel resistor (13, 23) connected in parallel with the surge capacitance (11, 21) and the switching device, a series resistor (14, 24) connected in series with the surge capacitance, the switching device and the parallel resistor (13, 23), and a load capacitance (4), including the capacitance of the unit under test, connectable to said at least one stage (1, 2), said circuit having at least one additional circuit element (5, 5′

, 6, 7) which includes a compensation capacitance (51, 51′

, 61, 71) and at least one discharge element (52, 52′

, 62, 72) connected in parallel with the compensation capacitance (51, 51′

, 61, 71) to compensate for unwanted oscillatory overshoot of pulse fronts of the flashed pulsed voltage across the load capacitance (4).

2. A pulsed-voltage generator circuit according to claim 1, wherein the switching device is at least one switching spark gap (12, 22).

3. A pulsed-voltage generator circuit according to claim 1 or 2, wherein said at least one additional circuit element (5, 5′

, 6) is connected in series downstream of the series resistor (14, 24) in a stage (1, 2) which can be charged.

4. A pulsed-voltage generator circuit according to claim 3, wherein said at least one stage is a plurality of stages (1, 2) which can be charged, wherein said at least one additional circuit element (5, 5′

, 6) is connected in series downstream of the series resistor (14, 24) in the last of said at least one stage (1, 2) which can be charged.

5. A pulsed-voltage generator circuit according to claim 4, wherein one of said at least one additional circuit (5, 5′

, 6) is connected in series downstream of the series resistor (14, 24) in each said at least one stage (1, 2) which can be charged.

6. A pulsed-voltage generator circuit according to claim 1 or 2, wherein said at least one additional circuit element (7) is connected upstream of said at least one stage (1) which can be charged.

7. A pulsed-voltage generator circuit according to claim 6, wherein said at least one additional circuit element (7) has, connected in series, a compensation spark gap (73) and a compensation capacitance (71), and, connected in parallel with the compensation spark gap (73) and the compensation capacitance (71), a charge resistor (74) and a discharge spark gap (72), in such a manner that the compensation capacitance (71) is also charged while the downstream stage (1) which can be charged is being charged and, when the stage (1) which can be charged is being discharged, is connected in a first phase by striking of the compensation spark gap (73) such that the voltage on the stage (1) which can be charged is reduced by the voltage across the compensation capacitance (71) and, in a second phase, is shorted by striking the discharge spark gap (72).

8. A pulsed-voltage generator circuit according to claim 1, wherein the discharge spark gap (62, 72) can be triggered with a delay with respect to the tripping of the switching device by striking of the switching spark gap (12), of the associated stage (1) which can be charged.

9. A pulsed-voltage generator circuit according to claim 1, wherein said at least one stage (1, 2) includes a first stage (1) and a second stage (2), said first stage (1) and said second stage (2) connectable such that each can be charged connected in parallel and discharged connected in series.

10. The pulsed-voltage generator circuit of claim 1, wherein said at least one additional circuit element (5, 5′

, 6, 7) has at least one discharge resistor (52, 52′

) and in series at least one inductance (53, 53′

), that are both connected in parallel with the compensation capacitance (51, 51′

, 61, 71), for compensating an unwanted oscillatory overshoot of pulse fronts of the flash pulsed voltage across the load capacitance (4).

11. The pulsed-voltage generator circuit of claim 1, wherein said at least one additional circuit element (5, 5′

, 6, 7) has at least one discharge spark gap (62, 72) connected in parallel with the compensation capacitance (51, 51′

, 61, 71) for compensating an unwanted oscillatory overshoot of pulse fronts of the flash pulsed voltage across the load capacitance (4).

12. An additional circuit element for a pulsed-voltage generator circuit which serves for producing a flash pulsed voltage for testing the capacitance of a unit under test and having at least one stage (1, 2) which can be charged, said at least one stage (1, 2) having, connected in series, a surge capacitance (11, 21) and a switching device, a parallel resistor (13, 23) connected in parallel with the surge capacitance (11, 21) and the switching device and, connected in series with the surge capacitance, the switching device and the parallel resistor, a series resistor (14, 24), two of said at least one stages (1, 2) being connectable to one another such that they can be charged connected in parallel and can be discharged connected in series, a load capacitance (4) including the capacitance of the unit under test being connectable to said at least one stage (1, 2), said pulsed-voltage generator circuit having at least one additional circuit element (5, 5′

, 6, 7) for reducing the overshoot of the pulse fronts of the flash pulsed voltage across the load capacitance (4), comprising;

a compensation capacitance (51, 51′

, 61, 71) and, connected in parallel with it, at least one discharge element (52, 52′

, 62, 72).

13. The additional circuit element according to claim 12, wherein said additional circuit element has, connected in series, a compensation capacitance (71) and a compensation spark gap (73) and, connected in parallel with the compensation capacitance (71) and the compensation spark gap (73), a charge resistor (74) and a discharge spark gap (72).