IP Library › Granted Patent US 12,625,173
Granted Patent B2
US 12,625,173 · App. 18/498,899 · Granted May 12, 2026

Methods and apparatus for in-situ measurement of mutual inductance between embedded interconnects

Inventors: Aaron James Bluestone (Camarillo, CA); Erik Stephen Daniel (Simi Valley, CA); Khashayar Pirouzmand (Sherman Oaks, CA)
Assignee: THE BOEING COMPANY
G01R27/2611G01R19/0038H04B3/487
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Quick Facts
Patent No.
US 12,625,173
App. No.
18/498,899
Granted
May 12, 2026
Kind
B2
Abstract

A system and method for measuring mutual inductance between adjacent first communication transmission line and second communication transmission line is disclosed. The system includes a mutual inductance measurement circuit that includes a coupling generator which biases the first communication transmission line with a current ramp signal; a sample and hold circuit which captures an induced voltage on the second communication transmission line using a switched capacitor storage element; a switched capacitor integrator configured to integrate the induced voltage onto an output voltage node; and a comparator configured to switch states once the switched capacitor integration has surpassed a reference trippoint.

Claims (35)

1 . A system for measuring mutual inductance between an adjacent first communication transmission line and second communication transmission line, the system comprising:

a mutual inductance measurement circuit comprising:

a coupling generator which biases the first communication transmission line with a current ramp signal;

a sample and hold circuit which captures an induced voltage on the second communication transmission line using a switched capacitor storage element;

a switched capacitor integrator configured to integrate the induced voltage onto an output voltage node; and

a comparator configured to switch states once the switched capacitor integration has surpassed a reference trippoint.

2 . The system of claim 1 , wherein the coupling generator uses a DC current source and a capacitor to generate a linear voltage ramp and an op-amp feedback circuit which performs voltage-to-current conversion to generate the current ramp signal.

3 . The system of claim 1 , wherein the current ramp signal on the first communication transmission line induces the induced voltage on the second communication transmission line.

4 . The system of claim 1 , wherein the first communication transmission line is an aggressor line.

5 . The system of claim 1 , wherein the second communication transmission line is a victim line.

6 . The system of claim 1 , wherein the first communication transmission line and the second communication transmission line are high-speed analog communications channels.

7 . The system of claim 1 , wherein the first communication transmission line and the second communication transmission line are digital communications channels.

8 . The system of claim 7 , wherein the digital communications channels comprise application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs).

9 . The system of claim 1 , further comprising a processor configured to receive an output from the comparator and determine a magnitude of mutual inductance.

10 . The system of claim 1 , wherein the voltage comparator is a dynamic, clocked voltage comparator.

11 . A method to determine a mutual inductance between a first communication transmission line and a second communication transmission line, the method comprising:

providing a periodic coupling current ramp signal to a first communication transmission line that induces a voltage on a nearby second communication transmission line, wherein the voltage is sampled and held on a capacitor;

integrating the voltage onto a feedback capacitor of a switched capacitor integrator when the charge is positive due to a positive change in voltage of the periodic coupling ramp signal on the first communication transmission line;

integrating the voltage until the voltage crosses a known threshold as measured on a comparator; and

counting a number of cycles required to cross the known threshold to infer a mutual inductance between the first communication transmission line and the second communication transmission line.

12 . The method of claim 11 , wherein prior to the providing the periodic coupling ramp signal, the method comprises resetting the switched capacitor integrator by closing and reopening a switch in parallel with the switched capacitive integrator.

13 . The method of claim 11 , wherein the first communication transmission line is an aggressor line.

14 . The method of claim 11 , wherein the second communication transmission line is a victim line.

15 . The method of claim 11 , wherein the first communication transmission line and the second communication transmission line are high-speed analog communications channels.

16 . The method of claim 11 , wherein the first communication transmission line and the second communication transmission line are digital communications channels.

17 . The method of claim 16 , wherein the digital communications channels comprise application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs).

18 . The method of claim 11 , further comprising receiving, at a processor, an output from the comparator circuit and determining a capacitive-based coupling.

19 . A method to determine a mutual inductance between a first communication line and a second communication line, the method comprising:

providing a periodic coupling current ramp signal to a first communication transmission line that induces a voltage on a nearby second communication transmission line, wherein the voltage is sampled and held on a first capacitive storage element;

providing a periodic current pulse signal to the first communication transmission line that capacitively couples a charge onto the nearby second communication transmission line, wherein a non-ideality of the charge that is capacitively coupled is sampled and held on a second capacitive storage element;

removing the charge that is capacitively coupled from a measurement through a differential switched capacitor integrator;

integrating the voltage onto a feedback capacitor of the differential switched capacitor integrator when the charge is positive due to a positive change in voltage of the periodic coupling ramp signal on the first communication transmission line;

integrating the voltage until the voltage crosses a known threshold as measured on a comparator; and

counting a number of cycles required to cross the known threshold to infer a mutual inductance between the first communication transmission line and the second communication transmission line.

20 . The method of claim 19 , wherein prior to the providing the periodic coupling ramp signal, the method comprises resetting the differential switched capacitor integrator by closing and reopening a switch in parallel with the differential switched capacitor integrator.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 31, 2023
From: BLUESTONE, AARON JAMES; DANIEL, ERIK STEPHEN; PIROUZMAND, KHASHAYAR
To: THE BOEING COMPANY
Reel/Frame 065409/0127 →
Continuity (1)
Related Publication 20250138071A1 · May 1, 2025
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