Inductor arrangement
An inductor arrangement has a first inductor structure having one or more inductors at least partially on a first layer and a second inductor structure having one or more inductors at least partially on a second layer. The inductors are arranged such that currents induced by an external magnetic field are substantially cancelled in at least one of the first inductor structure and the second inductor structure. The, or each, inductor of the second inductor structure overlaps, at least partially, the, or each, inductor of the first inductor structure. An oscillator circuit having an inductor arrangement is also presented.
1. An inductor arrangement, comprising:
a first inductor structure comprising one or more inductors at least partially on a first layer; and
a second inductor structure comprising one or more inductors at least partially on a second layer; wherein
the inductors are arranged such that currents induced by an external magnetic field are substantially cancelled in at least one of the first inductor structure and the second inductor structure; and
the, or each, inductor of the second inductor structure overlaps, at least partially, the, or each, inductor of the first inductor structure.
2. The inductor arrangement of claim 1 , wherein a portion of the second inductor structure passes above or below a portion of the first inductor structure via the second layer.
3. The inductor arrangement of claim 1 , wherein:
the first layer is at a first depth with respect to a surface of a chip; and
the second layer is at a second depth with respect to the surface of the chip.
4. The inductor arrangement of claim 1 , wherein the first inductor structure comprises a first inductor and a second inductor that are coupled such that currents induced in the first inductor structure by the external magnetic field are substantially cancelled.
5. The inductor arrangement of claim 4 , wherein:
the first inductor is arranged to generate a first generated magnetic field and the second inductor is arranged to generate a second generated magnetic field when an operational current flows through the first and second inductors; and
the first and second generated magnetic fields are approximately equal and with opposite orientations such that they substantially cancel each other out.
6. The inductor arrangement of claim 4 , wherein the first inductor structure is substantially symmetric and comprises a first axis of symmetry between the first inductor and the second inductor.
7. The inductor arrangement of claim 4 , wherein the first inductor and the second inductor are adjacent.
8. The inductor arrangement of claim 4 , wherein:
the first inductor and the second inductor are substantially rectangular in shape, such that each inductor comprises a width and a length, the length being longer than the width.
9. The inductor arrangement of claim 4 , wherein:
the first inductor and the second inductor are substantially triangular in shape, such that each inductor comprises a width, a height and a length, the length being longer than each of the width and the height.
10. The inductor arrangement of claim 4 , wherein the second inductor structure comprises a third inductor.
11. The inductor arrangement of claim 10 , wherein the third inductor is arranged to generate a third generated magnetic field, the third generated magnetic field contributing to the external magnetic field provided to the first inductor structure.
12. The inductor arrangement of claim 10 , wherein the second inductor structure comprises a fourth inductor, the third inductor and the fourth inductor are coupled such that currents induced in the second inductor structure by the external magnetic field are substantially cancelled.
13. The inductor arrangement of claim 12 , wherein:
the first inductor is arranged to generate a first generated magnetic field and the second inductor is arranged to generate a second generated magnetic field when an operational current flows through the first and second inductors;
the first and second generated magnetic fields are approximately equal and with opposite orientations such that they substantially cancel each other out;
the third inductor is arranged to generate a third generated magnetic field and the fourth inductor is arranged to generate a fourth generated magnetic field when the operational current flows through the third and fourth inductors; and
the third and fourth generated magnetic fields are approximately equal and with opposite orientations such that they substantially cancel each other out.
14. The inductor arrangement of claim 1 comprising:
a third inductor structure comprising one or more inductors at least partially on a third layer, wherein the third inductor structure overlaps, at least partially, the first inductor structure and the second inductor structure.
15. The inductor arrangement of claim 14 , comprising:
a fourth inductor structure comprising one or more inductors at least partially on the third layer, wherein the fourth inductor structure overlaps, at least partially, the first inductor structure and the second inductor structure.
16. An oscillator circuit comprising an inductor arrangement, the inductor arrangement comprising:
a first inductor structure comprising one or more inductors at least partially on a first layer; and
a second inductor structure comprising one or more inductors at least partially on a second layer; wherein
the inductors are arranged such that currents induced by an external magnetic field are substantially cancelled in at least one of the first inductor structure and the second inductor structure; and
the, or each, inductor of the second inductor structure overlaps, at least partially, the, or each, inductor of the first inductor structure.
17. The oscillator circuit of claim 16 comprising a plurality of inverters.
18. An oscillator circuit comprising
a plurality of inductors, wherein each inductor is of opposite polarity to its neighboring inductors; and
a plurality of inverters, wherein each inverter is coupled to a next inverter via an inductor.
19. The oscillator circuit of claim 18 arranged as a quadrature oscillator circuit, wherein:
the plurality of inverters comprises a first, second, third and fourth inverter;
the plurality of inductors comprises a first, second, third and fourth inductor;
the first inverter is coupled to the second inverter via the first inductor;
the second inverter is coupled to the third inverter via the second inductor;
the third inverter is coupled to the fourth inverter via the third inductor;
the fourth inverter is coupled to the first inverter via the fourth inductor; and
the first inductor and the third inductor have the same polarity and are of opposite polarity to that of the second inductor and the fourth inductor.
20. A method of providing an inductor arrangement, comprising the steps of:
providing a first inductor structure comprising one or more inductors at least partially on a first layer; and
providing a second inductor structure comprising one or more inductors at least partially on a second layer; wherein
the inductors are arranged such that currents induced by an external magnetic field are substantially cancelled in at least one of the first inductor structure and the second inductor structure; and
the, or each, inductor of the second inductor structure overlaps, at least partially, the, or each, inductor of the first inductor structure.
21. A method of providing an oscillator circuit comprised of an inductor arrangement, comprising the steps of:
providing a first inductor structure comprising one or more inductors at least partially on a first layer; and
providing a second inductor structure comprising one or more inductors at least partially on a second layer; wherein
the inductors are arranged such that currents induced by an external magnetic field are substantially cancelled in at least one of the first inductor structure and the second inductor structure; and
the, or each, inductor of the second inductor structure overlaps, at least partially, the, or each, inductor of the first inductor structure.