Trans-impedance amplifier transfer function compensation
AssigneeIntel Corporation
InventorDaniel Wimmer
Life of this patent
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Abstract
Techniques are disclosed to compensate for changes in the impedance of stage(s) preceding a trans-impedance amplifier (TIA) that is used within an RF chain. The techniques identify the changes in the source impedance value of the input stage (e.g., the mixers and LNAs) as a result of a gain state change, which alters the signal-to-transfer function (STF) of the TIA during operation and negatively impacts radio performance. The STF is maintained for changes in the source impedance value throughout different gain states without using switchable shunt components by using tunable elements to compensate for the source impedance changes, thus keeping the STF constant.
Claims20
A filter circuit having a signal-transfer function (STF), the filter circuit comprising:
- an input stage coupled to a source impedance, the source impedance being associated with a preceding stage having an adjustable gain that, when changed, causes a change in the source impedance;
- an output stage;
- and
- tunable circuitry coupled to the input stage and to the output stage,
- wherein a value of the tunable circuitry is adjustable to maintain the STF as the source impedance changes in response to changes in the adjustable gain of the preceding stage, and
- wherein the filter circuit includes amplification circuitry coupled to the input stage and to the output stage, such that the filter circuit operates as a 2nd-order low-pass trans-impedance amplifier (TIA).
A filter circuit having a signal-transfer function (STF), the filter circuit comprising:
- an input stage coupled to a source impedance, the source impedance being associated with a preceding stage having an adjustable gain that, when changed, causes a change in the source impedance;
- an output stage;
- and
- a tunable capacitor coupled to the input stage and to the output stage,
- wherein a capacitance of the tunable capacitor is adjustable to maintain the STF as the source impedance changes in response to changes in the adjustable gain of the preceding stage.
A filter circuit having a signal-transfer function (STF), the filter circuit comprising:
- an input stage coupled to a source impedance, the source impedance being associated with a preceding stage having an adjustable gain that, when changed, causes a change in the source impedance;
- an output stage;
- tunable circuitry coupled to the input stage and to the output stage;
- and
- amplification circuitry coupled to the input stage to provide a differential voltage signal Vout at the output stage,
- wherein a value of the tunable circuitry is adjustable to maintain the STF as the source impedance changes in response to changes in the adjustable gain of the preceding stage, and
- wherein the filter circuit is symmetric with respect to the amplification circuitry, the filter circuit having a tunable capacitor C1 coupled across two terminals that form the input stage.
Dependencies are inferred from the claim text.