Differential mode and common mode distortion cancellation circuitry
An electronic device may include wireless circuitry having one or more differential circuits. A differential circuit can include first and second input transistors, first and second degeneration components, and first and second distortion cancellation transistors cross-coupled with the first and second input transistors. The first distortion cancellation transistor can be configured to sense a voltage at the first input transistor and to produce corresponding currents for cancelling a differential mode harmonic distortion current flowing through the second input transistor and for cancelling a common mode harmonic distortion current flowing through the first input transistor. The second distortion cancellation transistor can be configured to sense a voltage at the second input transistor and to produce corresponding currents for cancelling a differential mode harmonic distortion current flowing through the first input transistor and for cancelling a common mode harmonic distortion current flowing through the second input transistor.
1 . A differential circuit comprising:
a first input transistor having a gate terminal configured to receive an input signal, a drain terminal coupled to a first output terminal of the differential circuit, and a source terminal;
a first passive component having a first terminal coupled to the source terminal of the first input transistor and having a second terminal coupled to a power supply line; and
a first distortion cancellation transistor having a gate terminal coupled to the gate terminal of the first input transistor and having a drain terminal directly coupled to the drain terminal of the first input transistor.
2 . The differential circuit of claim 1 further comprising:
a second input transistor having a gate terminal configured to receive the input signal, a drain terminal coupled to a second output terminal of the differential circuit, and a source terminal directly coupled to a source terminal of the first distortion cancellation transistor.
3 . The differential circuit of claim 2 further comprising:
a second passive component having a first terminal coupled to the source terminal of the second input transistor and having a second terminal coupled to the power supply line.
4 . The differential circuit of claim 3 further comprising:
a second distortion cancellation transistor having a gate terminal coupled to the gate terminal of the second input transistor and having a drain terminal coupled to the drain terminal of the second input transistor.
5 . The differential circuit of claim 4 wherein the second distortion cancellation transistor comprises a source terminal coupled to the source terminal of the first input transistor.
6 . The differential circuit of claim 5 wherein the first and second passive components comprise inductors.
7 . The differential circuit of claim 1 further comprising:
a capacitor having a first terminal coupled to the gate terminal of the first input transistor and having a second terminal configured to receive the input signal.
8 . The differential circuit of claim 7 further comprising:
a resistor coupled to a node between the gate terminal of the first input transistor and the first terminal of the capacitor.
9 . A differential circuit comprising:
a first input transistor having a gate terminal configured to receive an input signal, a drain terminal coupled to a first output terminal of the differential circuit, and a source terminal;
a first passive component having a first terminal coupled to the source terminal of the first input transistor and having a second terminal coupled to a power supply line; and
a first distortion cancellation component having a first terminal coupled to the gate terminal of the first input transistor and having a second terminal directly coupled to the drain terminal of the first input transistor.
10 . The differential circuit of claim 9 further comprising:
a second input transistor having a gate terminal configured to receive the input signal, a drain terminal coupled to a second output terminal of the differential circuit, and a source terminal directly coupled to a third terminal of the first distortion cancellation component.
11 . The differential circuit of claim 10 further comprising:
a second passive component having a first terminal coupled to the source terminal of the second input transistor and having a second terminal coupled to the power supply line.
12 . The differential circuit of claim 11 wherein the first and second passive components comprise degeneration inductors.
13 . The differential circuit of claim 10 further comprising:
a second distortion cancellation component having a first terminal coupled to the gate terminal of the second input transistor, a second terminal coupled to the drain terminal of the second input transistor, and a third terminal coupled to the source terminal of the first input transistor.
14 . The differential circuit of claim 13 wherein:
the first distortion cancellation component comprises a first distortion cancellation transistor having a gate terminal coupled to the gate terminal of the first input transistor, a drain terminal coupled to the drain terminal of the first input transistor, and a source terminal coupled to the source terminal of the second input transistor; and
the second distortion cancellation component comprises a second distortion cancellation transistor having a gate terminal coupled to the gate terminal of the second input transistor, a drain terminal coupled to the drain terminal of the second input transistor, and a source terminal coupled to the source terminal of the first input transistor.
15 . The differential circuit of claim 14 further comprising:
a first capacitor having a first terminal coupled to the gate terminal of the first distortion cancellation transistor and having a second terminal configured to receive the input signal;
a first resistor directly coupled to the first terminal of the first capacitor;
a second capacitor having a first terminal coupled to the gate terminal of the second distortion cancellation transistor and having a second terminal configured to receive the input signal;
a second resistor directly coupled to the first terminal of the second capacitor.
16 . A differential circuit comprising:
a first input transistor having a gate terminal configured to receive an input signal, a drain terminal coupled to a first output port of the differential circuit, and a source terminal;
a second input transistor having a gate terminal configured to receive the input signal, a drain terminal coupled to a second output port of the differential circuit, and a source terminal;
a first distortion cancellation component coupled to the first and second input transistors, the first distortion cancellation component being configured to produce currents for cancelling a differential mode harmonic distortion current flowing through the second input transistor and for cancelling a common mode harmonic distortion current flowing through the first input transistor based on a voltage at the gate terminal of the first input transistor; and
a second distortion cancellation component coupled to the first and second input transistors, the second distortion cancellation components being configured to produce currents for cancelling a differential mode harmonic distortion current flowing through the first input transistor and for cancelling a common mode harmonic distortion current flowing through the second input transistor based on a voltage at the gate terminal of the second input transistor.
17 . The differential circuit of claim 16 further comprising:
a first degeneration inductor coupled to the source terminal of the first input transistor; and
a second degeneration inductor coupled to the source terminal of the second input transistor.
18 . The differential circuit of claim 17 wherein:
the first distortion cancellation component comprises a first distortion cancellation transistor having a gate terminal coupled to the gate terminal of the first input transistor, the first distortion cancellation component being smaller than the first input transistor; and
the second distortion cancellation component comprises a second distortion cancellation transistor having a gate terminal coupled to the gate terminal of the second input transistor, the second distortion cancellation transistor being smaller than the second input transistor.
19 . The differential circuit of claim 18 wherein:
the first distortion cancellation transistor has a first source-drain terminal coupled to the drain terminal of the first input transistor and has a second source-drain terminal coupled to the source terminal of the second input transistor; and
the second distortion cancellation transistor has a first source-drain terminal coupled to the drain terminal of the second input transistor and has a second source-drain terminal coupled to the source terminal of the first input transistor.
20 . The differential circuit of claim 19 further comprising:
a first capacitor having a first terminal coupled to the gate terminal of the first distortion cancellation transistor and having a second terminal configured to receive the input signal; and
a second capacitor having a first terminal coupled to the gate terminal of the second distortion cancellation transistor and having a second terminal configured to receive the input signal.