Local oscillator driver circuitry with second harmonic rejection
AssigneeApple Inc.
InventorsOmar E Elaasar, Aly Ismail
Life of this patent
Estimating the term…
Abstract
An electronic device may include wireless circuitry having a mixer configured to receive an oscillating signal from oscillator circuitry. The oscillator circuitry can include a chain of buffer circuits referred to as oscillator driver circuitry. Transformers may be coupled at the input and output of each buffer circuit in the chain. Adjustable biasing circuits may be coupled at the input of a selected buffer circuit in the chain. The adjustable biasing circuits can be digital-to-analog converters (DACs) configured to apply a differential direct current (DC) offset voltage to the input of the selected buffer circuit. The differential DC offset voltage can have a value that minimizes a second harmonic component of the oscillator driver circuitry.
Claims20
Oscillator driver circuitry comprising:
- a first buffer circuit configured to receive an oscillating signal;
- a second buffer circuit having a first input configured to receive the oscillating signal from the first buffer circuit;
- and
- a first bias adjustment circuit coupled to the first input of the second buffer and configured to apply a first direct current (DC) offset voltage to the first input of the second buffer.
A buffer circuit comprising:
- a first input transistor having a gate terminal configured to receive an oscillating signal and having a source-drain terminal coupled to a first output of the buffer circuit;
- a second input transistor having a gate terminal configured to receive the oscillating signal and having a source-drain terminal coupled to a second output of the buffer circuit;
- and
- a first biasing circuit coupled to the gate terminal of the first input transistor and configured to apply a first offset voltage on the gate terminal of the first input transistor.
Circuitry comprising:
- a chain of buffer circuits configured to propagate an oscillating signal, wherein the chain of buffer circuits includes at least a first buffer circuit and a second buffer circuit having an input configured to receive the oscillating signal from the first buffer circuit;
- and
- one or more biasing circuits configured to apply an offset voltage to the input of the second buffer circuit in the chain of buffer circuits.
Dependencies are inferred from the claim text.