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.
Claims18
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 at least one preceding stage having an adjustable gain that, when changed, results in a change in the source impedance;
- an output stage;
- and
- at least one tunable component coupled between the input stage and the output stage,
- wherein a value of the at least one tunable component is adjustable to maintain the STF as the source impedance changes as a result of changes in the adjustable gain of the at least one preceding stage,
- wherein the source impedance is determined based upon values that correlate changes of the source impedance to changes in the adjustable gain of the at least one preceding stage, and
- wherein the value of the at least one tunable component is adjusted based upon the determined source impedance.
A device, comprising:
- a transceiver chain including:
- a filter circuit having a signal-transfer function (STF), the filter circuit having (i) an input stage coupled to a source impedance, the source impedance being associated with at least one preceding stage having an adjustable gain that, when changed, results in a change in the source impedance, (ii) an output stage, and (iii) at least one tunable component coupled between the input stage and the output stage;
- and
- processing circuitry configured to:
- adjust a value of the at least one tunable component to maintain the STF as the source impedance changes as a result of changes in the adjustable gain of the at least one preceding stage,
- calculate the source impedance based upon values that correlate changes of source impedance to changes in adjustable gain of the at least one preceding stage, and
- adjust the value of the at least one tunable component based upon the calculated source impedance.
A computer-implemented method for tuning a filter circuit having a signal-transfer function (STF), the method comprising:
- determining, by one or more processors, a gain state of at least one preceding stage associated with a source impedance with respect to the filter circuit, the at least one preceding stage having an adjustable gain that, when changed, results in a change in the source impedance;
- determining, by the one or more processors, a source impedance value associated with a current gain state of the at least one preceding stage;
- evaluating, by the one or more processors, tuning values for the filter circuit for the determined source impedance value;
- and
- transmitting, by the one or more processors, tuning control signals to the filter circuit to cause the filter circuit to adjust a value of at least one tunable component within the filter circuit in accordance with the tuning values to maintain the STF as the source impedance changes as a result of changes in the adjustable gain of the at least one preceding stage.
Dependencies are inferred from the claim text.