Even-order non-linearity correction feedback for Gilbert style mixers
AssigneeSkyworks Solutions, Inc.
InventorsGeoffrey Hatcher, Alyosha C. Molnar, Rahul Magoon
Life of this patent
Estimating the term…
Abstract
Double balanced mixers having transistor pairs are affected by area mismatches between the transistors. The area mismatches can be represented as a ratio between the mixer core transistors that is directly related to voltage. Thus, an input voltage into one of the mixer core transistors in a transistor pair can compensate for the area mismatch. The compensation is achieved by a voltage track and hold feedback loop to one of the mixer core transistors.
Claims23
An apparatus for signal mixing, comprising:
- a first set of transistors having a first transistor pair area ratio and a first bias voltage electrically connected to a first output branch;
- a second set of transistors having a second transistor pair area ratio and a second bias voltage electrically connected to a second output branch;
- and
- a correction loop operable connected to the first set of transistors, where the correction loop determines a delta bias voltage from a current in the first output branch and another current in the second output branch, and adjusts the first bias voltage on a transistor in the first transistor pair such that the current in the first output branch is equal to the other current in the second output branch.
A method for mixing signals, comprising:
- sensing a current in a first output branch that is electrically connected to a first pair of transistors;
- sensing another current in a second output branch that is electrically connected to a second pair of transistors;
- and
- adjusting the bias current on a transistor in the first pair of transistors in response to the first current and the second current.
An apparatus for signal mixing, comprising:
- a first set of transistors having a first transistor area ratio and a first bias voltage;
- a second set of transistors having a second transistor area ratio and a second bias voltage;
- a correction loop operable connected to the first set of transistors, the correction loop determines a delta bias voltage from the first bias voltage and the second bias voltage and adjusts the first bias voltage on a transistor in the first transistor pair by the delta bias voltage that is related to a variation of the first transistor area ratio and the second transistor area ratio by the formula, ΔVbe=Vtln[Δ(A)], where ΔVbe is the difference in the first bias voltage and the second bias voltage, Vt is an equal collector current applied to the first transistor pair and the second transistor pair, and Δ(A) is the difference in the first transistor area ratio and the second transistor area ratio;
- and
- a transistor that adjusts the first bias voltage in relation to the delta bias voltage.
An apparatus for signal mixing, comprising:
- a first set of transistors having a first transistor area ratio and a first bias voltage;
- a second set of transistors having a second transistor area ratio and a second bias voltage;
- a means for determining a delta bias voltage from the first bias voltage and the second bias voltage operable connected to the first set of transistors;
- and
- a means for adjusting the first bias voltage at a transistor in the first transistor pair by the delta bias voltage.
Dependencies are inferred from the claim text.