Current-mode power amplifier

Patent metadata

Field	Value
Publication number	US-9712115-B2
Application number	US-201514950295-A
Country	US
Kind code	B2
Filing date	Nov 24, 2015
Priority date	Nov 24, 2015
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A current-mode power amplifier is disclosed. In some embodiments, the power amplifier may include a first cascode transistor pair including a first transfer function coupled to a second cascode transistor pair including a second transfer function. The first transfer function may be an inverse of the second transfer function. The current-mode power amplifier may also include an inductive-capacitive (LC) resonant circuit to reduce the effects of gate capacitances of the first cascode transistor pair and the second cascode transistor pair. In some embodiments, the current-mode power amplifier may include a bias current controller. The bias current controller may adjust transistor bias currents based, at least in part, on an input signal received by the current-mode power amplifier.

First claim

What is claimed is:

1. A current mirror, comprising:
a first transistor including a drain terminal configured to receive a first radio frequency (RF) input;
a second transistor including a source terminal coupled to a source terminal of the first transistor and a gate terminal coupled to a gate terminal of the first transistor; and
an inductor, including a first terminal coupled to the gate terminal of the second transistor, the inductor configured to form a first inductive-capacitive (LC) resonant circuit with a gate capacitance of the second transistor.

2. The current mirror of claim 1 , wherein the second transistor is configured to generate an RF output current based, at least in part, on a first RF input current.

3. The current mirror of claim 1 , wherein the LC resonant circuit is configured to increase an input impedance of the second transistor near a resonant frequency of the LC resonant circuit.

4. The current mirror of claim 1 , further comprising:
a variable current source configured to generate a first bias current for the first transistor based, at least in part, on a voltage envelope of an RF input signal.

5. The current mirror of claim 1 , further comprising:
a first common-gate amplifier coupled to the first transistor to form a first cascode transistor pair; and
a second common-gate amplifier coupled to the second transistor to form a second cascode transistor pair.

6. The current mirror of claim 1 , further comprising:
a third transistor; and
a fourth transistor including a source terminal coupled to a source terminal of the third transistor and a gate terminal coupled to a gate terminal of the third transistor and a second terminal of the inductor.

7. The current mirror of claim 6 , wherein:
a drain terminal of the first transistor is configured to receive a first RF input current; and
a drain terminal of the third transistor is configured to receive a second RF input current, wherein the first RF input current is a first signal of a differential signal pair and the second RF input current is a second signal of the differential signal pair.

8. A power amplifier, comprising:
a driver amplifier configured to receive a radio frequency (RF) input signal and to generate a buffered RF input signal;
a bias current controller, coupled to the driver amplifier, configured to generate a bias current based, at least in part, on the RF input signal; and
a resonant current mirror output stage configured to amplify the buffered RF input signal based, at least in part, on the bias current, the resonant current mirror output stage comprising:
a first transistor including a drain terminal configured to receive at least a portion of the buffered RF input signal;
a second transistor including a source terminal coupled to a source terminal of the first transistor and a gate terminal coupled to a gate terminal of the first transistor; and
an inductor, including a first terminal coupled to the gate terminal of the second transistor, the inductor configured to form an inductive-capacitive (LC) resonant circuit with a gate capacitance of the second transistor.

9. The power amplifier of claim 8 , wherein at least a portion of the buffered RF input signal is coupled to the gate terminal of the second transistor.

10. The power amplifier of claim 8 , further comprising:
a first common-gate amplifier coupled to the first transistor to form a first cascode transistor pair; and
a second common-gate amplifier coupled to the second transistor to form a second cascode transistor pair.

11. The power amplifier of claim 8 , wherein the second transistor is configured to generate an RF output signal based, at least in part, on at least a portion of the buffered RF input signal.

12. The power amplifier of claim 11 , further comprising:
an antenna; and
an output balun to couple the RF output signal to the antenna.

13. The power amplifier of claim 8 , wherein the buffered RF input signal is a current-mode signal.

14. The power amplifier of claim 8 , further comprising:
a third transistor; and
a fourth transistor including a source terminal coupled to a source terminal of the third transistor, and a gate terminal coupled to a gate terminal of the third transistor and a second terminal of the inductor.

15. A power amplifier comprising:
a first cascode transistor pair configured to implement a first transfer function;
a second cascode transistor pair, coupled to the first cascode transistor pair, configured to implement a second transfer function that is an inverse of the first transfer function; and
an inductor, coupled to the first cascode transistor pair and the second cascode transistor pair, configured to form an inductive-capacitive (LC) resonant circuit with a gate capacitance of the first cascode transistor pair and a gate capacitance of the second cascode transistor pair.

16. The power amplifier of claim 15 , further comprising:
a variable current source configured to generate a bias current for the first cascode transistor pair based, at least in part, on a voltage envelope of an RF input signal.

17. The power amplifier of claim 15 , wherein the LC resonant circuit is configured to increase an input impedance of the power amplifier near a resonant frequency of the LC resonant circuit.

18. A current mirror, comprising:
a first transistor;
a second transistor including a source terminal coupled to a source terminal of the first transistor and a gate terminal coupled to a gate terminal of the first transistor;
a third transistor;
a fourth transistor including a source terminal coupled to a source terminal of the third transistor and a gate terminal coupled to a gate terminal of the third transistor; and
an inductor, including a first terminal coupled to the gate terminal of the second transistor and a second terminal coupled to the gate terminal of the fourth transistor, the inductor configured to form a first inductive-capacitive (LC) resonant circuit with a gate capacitance of the second transistor.

19. The current mirror of claim 18 , wherein:
a drain terminal of the first transistor is configured to receive a first radio frequency (RF) input current; and
a drain terminal of the third transistor is configured to receive a second RF input current, wherein the first RF input current is a first signal of a differential signal pair and the second RF input current is a second signal of the differential signal pair.

20. The current mirror of claim 18 , wherein the second transistor is configured to generate an RF output current based, at least in part, on a first RF input current.

21. The current mirror of claim 18 , wherein the LC resonant circuit is configured to increase an input impedance of the second transistor near a resonant frequency of the LC resonant circuit.

22. The current mirror of claim 18 , further comprising:
a variable current source configured to generate a first bias current for the first transistor based, at least in part, on a voltage envelop of an RF input signal.

23. The current mirror of claim 18 , further comprising:
a first common-gate amplifier coupled to the first transistor to form a first cascode transistor pair; and
a second common-gate amplifier coupled to the second transistor to form a second cascode transistor pair.

Assignees

• Qualcomm Inc

Inventors

• Talwalkar Niranjan

Classifications

• H03F2200/06

  A balun, i.e. balanced to or from unbalanced converter, being present at the input of an amplifier · CPC title

• H03F3/193

  with field-effect devices (H03F3/195 takes precedence) · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title

• H03F1/0205 Primary

  in transistor amplifiers · CPC title

• H03F3/21

  with semiconductor devices only {(H03F3/245 takes precedence)} · CPC title