Electronic devices with differential LC filters
AssigneeApple Inc.
InventorMilad Darvishi
Life of this patent
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Abstract
An electronic device may include wireless circuitry having an LC filter. The LC filter may include first and second series inductors coupled between the input and output of the LC filter. An input capacitor can be coupled at the input of the LC filter, and an output capacitor can be coupled at the output of the LC filter. Feedforward capacitors can be cross-coupled with the first and second series inductors to at least partially or fully cancel out any parasitic capacitance associated with the first and second series inductors to mitigate any undesired self-resonant effects associated with the series inductors.
Claims19
A filter circuit comprising:
- a first inductor having a first terminal coupled to a first input port of the filter circuit and having a second terminal coupled to a first output port of the filter circuit;
- a second inductor having a first terminal coupled to a second input port of the first circuit and having a second terminal coupled to a second output port of the filter circuit;
- a first feedforward capacitor having a first terminal coupled to the first terminal of the first inductor and having a second terminal coupled to the second terminal of the second inductor;
- a second feedforward capacitor having a first terminal coupled to the first terminal of the second inductor and having a second terminal coupled to the second terminal of the first inductor;
- and
- a parallel capacitor coupled across the first terminals of the first and second inductors.
A filter circuit comprising:
- a first series inductor coupled between a differential input and a differential output of the filter circuit;
- a second series inductor coupled between the differential input and the differential output of the filter circuit;
- a first capacitance neutralization capacitor cross-coupled with the first and second series inductors, the first capacitance neutralization capacitor being configured to at least partially cancel a parasitic capacitance associated with the first series inductor;
- and
- an output capacitor coupled across the differential output of the filter circuit.
An electronic device comprising:
- one or more processors configured to generate baseband signals;
- and
- a differential filter configured to filter the baseband signals, the differential filter including
- a first series inductor coupled between an input and an output of the differential filter,
- a second series inductor coupled between the input and the output of the differential filter, and
- a plurality of inductor self resonance mitigation capacitors cross-coupled with the first and second series inductors, wherein the differential filter has a notch frequency that is based on capacitance values of the plurality of inductor self resonance mitigation capacitors.
Dependencies are inferred from the claim text.