LOCATING SHORT CIRCUITS IN PRINTED CIRCUIT BOARDS
First Claim
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1. A method of locating a short circuit between two layers of a printed circuit board, the method comprising:
- selecting first, second, and third non-collinear test points in one of the two layers;
injecting a first test signal at the first test point and determining a first distance to the short circuit according to a signal reflection from the injected first test signal;
injecting a second test signal at the second test point and determining a second distance to the short circuit according to a signal reflection from the injected second test signal;
injecting a third test signal at the third test point and determining a third distance to the short circuit according to the signal reflection from the injected third test signal; and
identifying the location of the short circuit as being the first distance from the first test point, the second distance from the second test point, and the third distance from the third test point.
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Abstract
One embodiment provides a method of locating a short circuit in a printed circuit board. Test signals may be injected at different test points on the circuit board. The distance between each test point and the short circuit may be determined according to how long it takes for a signal reflection at the short circuit to propagate back to each test point. The distances between the various test points and the short circuit can be used to narrow the possible locations of the short circuit or even to pinpoint the location of the short circuit.
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Citations
16 Claims
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1. A method of locating a short circuit between two layers of a printed circuit board, the method comprising:
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selecting first, second, and third non-collinear test points in one of the two layers; injecting a first test signal at the first test point and determining a first distance to the short circuit according to a signal reflection from the injected first test signal; injecting a second test signal at the second test point and determining a second distance to the short circuit according to a signal reflection from the injected second test signal; injecting a third test signal at the third test point and determining a third distance to the short circuit according to the signal reflection from the injected third test signal; and identifying the location of the short circuit as being the first distance from the first test point, the second distance from the second test point, and the third distance from the third test point. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of locating a short circuit between two layers of a printed circuit board, the method comprising:
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selecting first and second test points in one of the two layers within 1 cm of an edge of the printed circuit board; injecting a first test signal at the first test point and determining a first distance to the short circuit according to a signal reflection from the injected first test signal; injecting a second test signal at the second test point and obtaining a second distance to the short circuit according to a signal reflection from the injected second test signal; and identifying the location of the short circuit as a unique point located the first distance from the first test point, the second distance from the second test point, and within the printed circuit board. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A computer program product including computer usable program code embodied on a computer usable storage medium for locating a short circuit in a printed circuit board, the computer program product including:
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computer usable program code for injecting a first test signal at a first test point and determining a first distance to the short circuit according to a signal reflection from the injected first test signal; computer usable program code for injecting a second test signal at a second test point and obtaining a second distance to the short circuit according to a signal reflection from the injected second test signal; computer usable program code for injecting a third test signal at a third test point and obtaining a third distance to the short circuit according to the signal reflection from the injected third test signal; and computer usable program code for identifying the location of the short circuit as being the first distance from the first test point, the second distance from the second test point, and the third distance from the third test point.
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Specification