Substrate-embedded AC sensors
AC current sensors are described having a primary current path that is integrated in a substrate or separate from the substrate; one or more conductive loops integrated in the substrate and configured for inductive coupling with the primary current path; and an integrated circuit connected to the conductive loop(s) and configured to measure AC current in the primary current path. The one or more integrated coils or loops can include one or more twisted loops configured to provide differential sensing of current in the primary current path and reject stray magnetic fields. In some embodiments, the one or more integrated coils or loops include one or more pairs of integrated coils or loops, with one coil or loop of each pair on each side of the main current path.
1 . An AC current sensor comprising:
a busbar;
an integrated coil integrated in a substrate and configured for inductive coupling with the busbar, wherein the integrated coil includes a twisted loop, and wherein the integrated coil is configured to provide differential sensing of current in the busbar and to reject stray magnetic fields, wherein the twisted loop includes a cross-over portion between first and second coil portions, wherein the cross-over portion is substantially aligned with a longitudinal axis of the busbar such that electromagnetic fields of the first coil portion and the second coil portion are additively combined during differential sensing of the current in the busbar; and
an integrated circuit (IC) connected to the integrated coil and configured to measure AC current in the busbar.
2 . The sensor of claim 1 , wherein the substrate comprises a printed circuit board (PCB).
3 . The sensor of claim 2 , wherein the busbar is integrated into the PCB.
4 . The sensor of claim 2 , wherein the PCB comprises FR-4.
5 . The sensor of claim 2 , wherein the PCB comprises FR-5.
6 . The sensor of claim 1 , wherein the substrate comprises a ceramic substrate.
7 . The sensor of claim 1 , wherein the substrate comprises a glass substrate including one or more layers of glass alternating with one or more respective layers of metal.
8 . The sensor of claim 1 , wherein the busbar is integrated into the substrate.
9 . The sensor of claim 1 , wherein the busbar is separate from the substrate.
10 . An AC current sensor comprising:
a busbar;
an integrated coil integrated in a substrate and configured for inductive coupling with the busbar, wherein the integrated coil is configured to sense current in the busbar, wherein the integrated coil includes a twisted loop, wherein the twisted loop includes a cross-over portion between first and second coil portions, wherein the cross-over portion is substantially aligned with a longitudinal axis of the busbar such that electromagnetic fields of the first coil portion and the second coil portion are additively combined during differential sensing of the current in the busbar; and
an integrated circuit (IC) connected to the integrated coil and configured to measure AC current in the busbar.
11 . The sensor of claim 10 , wherein the substrate comprises a printed circuit board (PCB).
12 . The sensor of claim 11 , wherein the busbar is integrated into the PCB.
13 . The sensor of claim 11 , wherein the PCB comprises FR-4.
14 . The sensor of claim 11 , wherein the PCB comprises FR-5.
15 . The sensor of claim 10 , wherein the substrate comprises a ceramic substrate.
16 . The sensor of claim 15 , wherein the substrate comprises a glass substrate including one or more layers of glass alternating with one or more respective layers of metal.
17 . The sensor of claim 10 , wherein the substrate comprises a glass substrate including one or more layers of glass alternating with one or more respective layers of metal.
18 . The sensor of claim 10 , wherein the busbar is integrated into the substrate.
19 . The sensor of claim 10 , wherein the busbar is separate from the substrate.
20 . An AC current sensor comprising:
a busbar;
one or more pairs of coils integrated in a substrate and configured for inductive coupling with the busbar, wherein each pair of integrated coils includes a first coil and a second coil, and is configured to sense current in the busbar and to reject stray magnetic fields, wherein the first coil and the second coil form a twisted loop with a cross-over portion between the first and second coils that is substantially aligned with a longitudinal axis of the busbar such that electromagnetic fields of the first coil and the second coil are additively combined during sensing of the current in the busbar; and
an integrated circuit (IC) connected to the one or more pairs of integrated coil and configured to measure AC current in the busbar.
21 . The sensor of claim 20 , wherein the substrate comprises a printed circuit board (PCB).
22 . The sensor of claim 21 , wherein the busbar is integrated into the PCB.
23 . The sensor of claim 21 , wherein the PCB comprises FR-4.
24 . The sensor of claim 21 , wherein the PCB comprises FR-5.
25 . The sensor of claim 20 , wherein the substrate comprises a ceramic substrate.
26 . The sensor of claim 20 , wherein the busbar is integrated into the substrate.
27 . The sensor of claim 20 , wherein the busbar is separate from the substrate.
28 . A method of making an AC current sensor, the method comprising:
providing a primary current path;
providing an integrated coil integrated in a substrate, wherein the integrated coil is configured to detect current in the primary current path, wherein the integrated coil includes a twisted loop that includes a cross-over portion between first and second coil portions of the integrated coil, wherein the cross-over portion is substantially aligned with a longitudinal axis of the primary current path such that electromagnetic fields of the first coil portion and the second coil portion are additively combined during detection of the current in the primary current path; and
providing an integrated circuit (IC) connected to the integrated coil and configured to measure AC current in the primary current path.
29 . The method of claim 28 , wherein the primary current path comprises a busbar.
30 . The method of claim 29 , wherein the busbar is integrated into the substrate.
31 . The method of claim 28 , wherein the primary current path comprises a conductive trace disposed in the substrate.
32 . The method of claim 28 , wherein the twisted loop is configured to reject stray magnetic fields.
33 . The method of claim 28 , wherein the substrate comprises a printed circuit board (PCB).