Device for testing a network of components, in particular an electronic circuit

• US 5,182,717 A
• Filed: 07/05/1990
• Issued: 01/26/1993
• Est. Priority Date: 07/13/1989
• Status: Expired due to Fees

• Current Assignee: Dassault Electronique
• Original Assignee: Dassault Electronique
• Inventors: Luciani, Pierre, Tallibert, Patrick, Deves, Philippe
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Ramirez, Ellis B.
• Application Number:
  US07/548,381
• Time in Patent Office: 936 Days
• Field of Search: 364/481, 364/482, 364/483, 324/77 R, 324/77 A, 324/77 B, 324/615, 324/629, 324/649, 324/608, 324/650
• US Class Current: 702/118
• CPC Class Codes: G01R 31/2846 using hard- or software simulation or using knowledge-based systems, e.g. expert systems, artificial intelligence or interactive algorithms
• CPC Class Codes: G06F 11/2257 using expert systems

Abstract

Device for testing a network of components, in particular an electronic circuit.

The respective potential differences between the terminals of the circuit to be tested are acquired during a chosen time interval and stored in a values memory. A memory contains predetermined functional models of electronic components. The processing means, connected to these memories, are capable of effecting a processing comprising the estimation, during said time interval, of physical values, notably of current-expressions, taking account of expressions contained in said acquired models and values, and storing them in the values memory as well as tests on the values contained in the values memory.

Claims

1. An electronic device for testing a network of components, comprising

(A) interface means comprising

(Aa) means for defining sampling instants in a chosen time interval,

(Ab) means for identifying at least one component of the network,

(Ac) probe means for the acquisition of a physical value relating to the state of functioning of this component, and

(Ad) means cooperating with the probe for providing a series of samples of this physical value within the chosen time interval;

(B) a functional models memory contains component expressions relating to physical values concerning at least one particular kind of component;

(C) a values memory for storing several sample series of physical values corresponding to the same time interval but relating to different components of said network; and

(D) processing means connected to said values memory and to said functional models memory and to said interface means for effecting a processing procedure comprising an estimation of the physical values over said time interval, taking into account the expressions contained in said models memory and the acquired samples and their storage in the values memory, as well as tests on the values contained in the values memory,

wherein said functional models memory further contains law-expressions representing general relationships between physical values;

wherein at least some of said acquired samples are stored in said functional models memory with precision brackets;

wherein the expressions for functional models stored in said functional models memory are at least in part provided with uncertainty brackets;

wherein any estimation is stored in said functional models memory with its estimated uncertainty bracket deriving from at least some of said uncertainty brackets and said precision brackets; and

wherein when said functional models memory contains, for at least some of the sampling instants, a first bracket and a second bracket of different origins for the same physical value established on the basis of the contribution of a primary set of components, these two brackets are compared, and the processor means is adapted for deducing therefrom first information regarding the functioning of the components of this primary set.

2. A device according to claim 1, wherein each of the first and second brackets belongs to a group of brackets comprising estimated precision brackets and estimated uncertainty brackets.

3. A device according to claim 2, wherein some at least of the component models comprise at least one reference bracket referring to the particular physical values relating to these components, and

wherein said group of brackets further comprises the reference bracket or brackets.

4. A device according to claim 1, wherein said means for defining the sampling instants are controllable.

5. A device according to claim 1, wherein component-expressions contained in said functional models memory refer to a correct functioning of the components.

6. A device according to claim 1, wherein, when said first and second brackets are disjoint over at least a significant fraction of said time interval, said first information represents an incorrect functioning of at least one component of said primary set of components.

7. A device according to claim 6, wherein said processing means is such that, when a primary set of components has led to the obtaining of two disjoint brackets and to the satisfying of a predetermined condition, said processing means effects a selective acquisition of physical values relating to certain components of said primary set.

8. A device according to claim 6, wherein, when two different primary sets have led to the obtaining of two disjoint brackets, the component or components suspected of an incorrect functioning appertains to the intersection of said two primary sets.

9. A device according to claim 8 wherein said processing means is operative to effect the processing at least until two primary sets are obtained whose intersection comprises a single component.

10. A device according to claim 6, wherein said significant fraction of the time interval comprises a predetermined number of successive sampling instants.

11. A device according to claim 10, wherein said predetermined number is at least two.

12. A device according to claim 1, wherein, when said first and second brackets have an intersection bracket that is not empty, this intersection bracket is assigned to said physical value on a priority basis.

13. A device according to claim 1, wherein said processing means are capable of an estimation for at least some of the components of at least one physical value belonging to the group comprising :

the physical values of a kind different from those already respectively acquired for these components, and

the physical values already respectively acquired for these components;

and wherein said estimation is obtained on the basis of at least one of the values of said values memory.

14. A device according to claim 1, wherein, for an estimated physical value obtained on the basis of a formulation relying on the intervention of a plurality of different physical values, the said formulation is arranged so as to mention each different physical value only once.

15. A device according to claim 1, further comprising a memory capable of memorizing the network configuration.

16. A device according to claim 15, wherein said processing means includes a decision-making mechanism connected to the structure of said network, said decision making mechanism comprising a first mechanism referring to the determination of the choice and order of the components in respect of which the various physical values will be acquired, and a second mechanism referring to the estimations of the physical values.

17. A device according to claim 16, wherein said network of components comprises a plurality of grids and wherein said second mechanism comprises:

for a component of a grid that has given rise to an acquisition of a physical value of a chosen kind, an estimation of at least one physical value of a kind different from that of the chosen kind, taken from a functional model of said component and from samples of said acquired physical value,

for a component that has not given rise to an acquired physical value of a chosen kind and belonging to said grid or directly connected to a component of said grid, an estimation of at least one of the group comprising at least one physical value of the same kind as the kind chosen, and at least one physical value of a different kind, obtained on the basis of values already stored in the values memory and associated with at least one component of said grid.

18. A device according to claim 11, wherein said processing means includes a decision-making mechanism connected to the structure of said network, said decision making mechanism comprising a first mechanism referring to the determination of the choice and order of the components in respect of which the various physical values will be acquired, and a second mechanism referring to the estimations of the physical values;

and wherein said second mechanism is capable of using said intersection bracket for other estimations of physical values.

19. A device according to claims 16, wherein said network of components comprises a plurality of grids, and wherein said first mechanism comprises a first decision making criterion relating to the selection of a grid within which at least one physical value will be acquired.

20. A device according to claim 19, wherein said first criterion comprises a first subcriterion relating to the number of physical values already known within each said grid.

21. A device according to claim 20, wherein in the case of a possible selection of at least two grids according to said first subcriterion, said first criterion comprises a second subcriterion relating to the number of the components of said at least two grids.

22. A device according to claim 21, wherein said second subcriterion comprises the preferential selection of a said grid according to its number of components taken in the order of 3, 4, 2.

23. A device according to claim 21, wherein in the case of a possible selection of at least two said grids according to said second subcriterion, said first criterion comprises a third subcriterion relating to the kind of components of these said at least two grids.

24. A device according to claim 17, wherein within a selected said grid, said first mechanism comprises a second decision making criterion relating to the kind of components of said selected grid.

25. A device according to claim 1, wherein said network of components is an electronic circuit.

26. A device according to claim 25, wherein the acquired physical values belong to the group comprising current expressions and potential differences.

27. A device according to claim 26, wherein the estimated physical values belong to the group comprising current expressions and potential differences.

28. A device according to claim 23, wherein said network of components is an electronic circuit, and wherein the grid selected according to the third subcriterion is the one having the greatest number of passive components.

29. A device according to claim 24, wherein said network of components is an electronic circuit and wherein said second decision-making criterion comprises the acquisition of a potential difference preferentially at the terminals of a passive said component.

30. A device according to claim 29, characterized in that where there are several said passive components, the potential difference is preferentially acquired at the terminals of a dipole.

31. A device according to claim 6, wherein said network of components comprises an electronic circuit, and wherein the acquisition of a potential difference is effected at the terminals of components of the primary set in respect of which this acquisition has not yet already been effected, unless said primary set only comprises components connected to a common terminal.

32. A device according to claim 25, wherein said processing means is operative to effect processing which comprises:

for at least some of the components of the circuit, on the basis of the acquisition of a potential difference between a first and a second terminal of one of these components, the estimation of the potential difference between the second and first terminals, and the estimations of the currents at each of these two terminals,

for a component having one terminal connected to a nodal point of the network to which there are also connected the respective terminals of other components in respect of which the respective currents at said respective terminals are known, the estimation of the current at the terminal of the said component,

for a component belonging to a grid whose potential differences at the terminals of the other components of said grid are known, the estimation of the potential differences at the terminals of this component.

33. A device according to claim 25, wherein said law-expressions take into account at least one rule based on:

the zero value of the total current at a nodal point of the circuit, and

the zero value of the sum of potential differences along one grid.

34. A device according to claim 25, wherein one of the physical values lending itself to a comparison of the two brackets belongs to the group comprising the emitter current of a transistor, its base current, its collector current, and the potential differences between two of its three terminals.

35. A device according to claim 25, wherein one of the physical values lending itself to a comparison of the two brackets is the current passing through a semiconductor junction.

36. A device according to claim 35, wherein said semiconductor junction is a diode.

37. A device according to claim 25, wherein one of the physical values lending itself to a comparison of the two brackets is the potential difference at the terminals of a passive component.

38. A device according to claim 37, wherein said passive component is a resistor.

39. A device according to claim 23, wherein:

(i) said probe means is capable of picking up a potential difference between two chosen terminals of the circuit, said identification means identifying at least one component connected between said two chosen terminals;

(ii) said values memory is capable of storing several potential differences corresponding to the same time interval, taken between a first common terminal and various terminals adjoining the latter;

(iii) said processing means is operative for effecting for each potential difference, an estimation of a current expression taken from the functional model of the component concerned over said time interval; and

(iv) said processing means is capable of testing, on the set current expressions at each moment of said time interval, a condition taking into account the presumed zero value of the total current in said first common terminal, this test giving a first indication regarding the functioning of the components connected to said first common terminal.

40. A device according to claim 39, wherein at least some of the current expressions are current values;

and wherein the test of the set of current expressions comprises the algebraic sum of said current values.

41. A device according to claim 39, wherein said first indication represents an incorrect functioning of at least one component connected to said first common terminal, the set of these components having an incorrect functioning mode overall.

42. A device according to claim 39, wherein said first indication represents a respective individual incorrect functioning of a plurality of components connected to the said first common terminal, the set of the components connected to this common terminal having a correct functioning mode overall.

43. A device according to claim 39, wherein said functional models memory contains functional models representing a correct functioning for at least some of the components connected to said first common terminal.

44. A device according to claim 39, wherein said functional models memory contains functional models representing an incorrect functioning for at least some of the components connected to said first common terminal.

45. A device according to claim 42, wherein said functional models memory contains functional models representing a correct functioning for at least some of the components connected to said first common terminal;

wherein each current expression relating to each component connected to the first common terminal is taken from a functional model representing a correct functioning; and

wherein the condition taking into account the presumed zero value of the total current at said first common terminal is fulfilled.

46. A device according to claim 41 wherein said functional models memory contains functional models representing a correct functioning for at least some of the components connected to said first common terminal;

wherein said functional models memory contains functional models representing an incorrect functioning for at least some of the components connected to said first common terminal;

wherein a single current expression is taken from a functional model representing an incorrect functioning of the corresponding component connected to said common terminal, whilst the other current expressions relating to the other components are taken respectively from the functional model representing correct functioning modes; and

wherein the presumed zero value of the total current at said first common terminal is fulfilled.

47. A device according to claim 41, wherein said functional models memory contains functional models representing a correct functioning for at least some of the components connected to said first common terminal;

wherein each current expression relating to each component connected to said first common terminal is taken from a functional model representing correct functioning modes; and

wherein the test of the condition taking the presumed zero value of the total current is negative.

48. A device according to claim 47, wherein said processing means is capable of testing a second condition taking into account the presumed zero value of the total current at a second common terminal chosen from the terminals adjoining the first common terminal, this test giving a second indication regarding the functioning of the components connected to said common terminal;

and wherein the combination of the first and second indications is capable of giving a third indication regarding the functioning of a component connected between the first and second common terminals.

49. A device according to claim 39, wherein said functional models memory contains component-expressions of different complexities.

50. A device according to claim 39, wherein the test of said condition taking into account the presumed zero value of the total current at said common terminal comprises the comparison of an algebraic value with a reference value.

51. A device according to claim 39, wherein said probe means comprise two separate probes capable of being placed respectively at two terminals of the circuit.

52. A device according to claim 39, wherein said processing means is capable of memorizing the characteristics of the common terminal used for said acquisition as well as the characteristics of the components connected thereto, which allows a representation of the circuit to be built up on an incremental basis.

53. A device according to claim 1, wherein said interface means comprise dialogue means for dialogue with a potential user.

54. A device according to claim 53, wherein said processing means is capable of elaborating instructions for use and of communicating them by said dialogue means.

55. A device according to claim 53, wherein said functional models memory is capable of receiving particular functional models capable of being communicated to the processing means by said dialogue means.

56. A device according to claim 1, further comprising a separate acquisition device incorporating said probe means and including a digital link for connecting said acquisition means to said processing means.

57. A method of testing a network of components using an electronic device, comprising the steps of:

(Aa) defining sampling instants in a chosen time interval,

(Ab) identifying at least one component of the network,

(Ac) using probe means to acquire a physical value relating to the state of functioning of the one component, and

(Ad) providing a series of samples of this physical value within the chosen time interval;

(B) storing in a functional models memory component expressions relating to physical values concerning at least one particular kind of component;

(C) storing in a values memory several sample series of physical values corresponding to the same time interval but relating to different components of said network; and

(D) estimating the physical values over said time interval, taking into account the component expressions contained in said functional models memory and the acquired samples and their storage in the values memory, as well as tests on the values contained in the values memory,

wherein said functional models memory further contains law-expressions representing general relationships between physical values, and the method further comprises the steps of;

(E) storing at least some of said acquired samples in said functional models memory with precision brackets;

(F) providing the expression stored in said functional models memory, at least in part, with uncertainty brackets;

(G) storing any estimation in said functional models memory with its estimated uncertainty bracket deriving from at least some of said uncertainty brackets and said precision brackets; and

(H) when said functional models memory contains, for at least some of the sampling instants, a first bracket and a second bracket of different origins for the same physical value established on the basis of the contribution of a primary set of components, comparing these two brackets, and deducing therefrom first information regarding the functioning of the components of this primary set.