Power amplifier and operation method therefor

• US 8,922,281 B2
• Filed: 09/17/2013
• Issued: 12/30/2014
• Est. Priority Date: 09/15/2011
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Takahashi, Wataru, Matsui, Toshiki, Sakatsume, Jun
• Primary Examiner(s): NGUYEN, HIEU P
• Application Number:
  US14/029,042
• Publication Number:
  US 20140167856A1
• Time in Patent Office: 469 Days
• Field of Search: 330/295, 330/124.R, 330/53, 330/84, 330/286
• US Class Current: 330/295
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/108 A coil being added in the drain circuit of a FET amplifier stage, e.g. for noise reducing purposes
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/429 Two or more amplifiers or one amplifier with filters for different frequency bands are coupled in parallel at the input or output
• CPC Class Codes: H03F 2200/507 A switch being used for switching on or off a supply or supplying circuit in an IC-block amplifier circuit
• CPC Class Codes: H03F 2203/7215 the gated amplifier being switched on or off by a switch at the input of the amplifier
• CPC Class Codes: H03F 2203/7227 the gated amplifier being switched on or off by a switch in the supply circuit of the amplifier
• CPC Class Codes: H03F 2203/7236 the gated amplifier being switched on or off by putting into parallel or not, by choosing between amplifiers by (a ) switch(es)
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal

Abstract

In a power amplifier, in response to a power mode signal at a predetermined level, a first switch circuit supplies a signal to first and second amplifier devices that perform parallel operations. In response to the power mode signal at another level, the first switch circuit supplies a signal to the first amplifier device and stops supplying the signal to the second amplifier device such that the first amplifier device performs a standalone operation. One end of an impedance adjusting circuit is connected to a connection node between the outputs of the first and second amplifier devices, the other end of the impedance adjusting circuit is connected to one end of a second switch circuit, and the other end of the second switch circuit is connected to a ground potential. The impedance adjusting circuit includes a reactance element.

Claims

1. A power amplifier comprising:

an RF signal input terminal;

a first amplifier device;

a second amplifier device;

a load device;

a first switch circuit;

a second switch circuit; and

an impedance adjusting circuit;

wherein

a common electrode of the first amplifier device and a common electrode of the second amplifier device are connected to a ground potential, and an output electrode of the first amplifier device and an output electrode of the second amplifier device are connected to the load device;

the first switch circuit, in response to a power mode signal at a first voltage level, supplies an RF input signal of the RF signal input terminal to an input electrode of the first amplifier device and to an input electrode of the second amplifier device so that the first amplifier device and the second amplifier device perform parallel amplification operations on the RF input signal;

the first switch circuit, in response to the power mode signal at a second voltage level different from the first voltage level, supplies the RF input signal of the RF signal input terminal to the input electrode of the first amplifier device and substantially stops supplying of the RF signal to the input electrode of the second amplifier device so that the first amplifier device performs a stand-alone amplification operation on the RF input signal;

one end of the impedance adjusting circuit is connected to a connection node between the output electrode of the first amplifier device and the output electrode of the second amplifier device, the other end of the impedance adjusting circuit is connected to one end of the second switch circuit, and the other end of the second switch circuit is connected to the ground potential;

the impedance adjusting circuit includes a reactance element connected between the one end and the other end of the impedance adjusting circuit; and

the second switch circuit causes the one end and the other end of the second switch circuit to be electrically disconnected from each other in response to the power mode signal at the second voltage level, and causes the one end and the other end of the second switch circuit to be electrically connected to each other in response to the power mode signal at the first voltage level.

2. The power amplifier according to claim 1, wherein the reactance element connected between the one end and the other end of the impedance adjusting circuit includes a capacitive reactance element.

3. The power amplifier according to claim 2, wherein the reactance element connected between the one end and the other end of the impedance adjusting circuit includes an inductive reactance element connected in series with the capacitive reactance element.

4. The power amplifier according to claim 3, further comprising:

an output matching circuit whose input terminal is connected to the output electrode of the first amplifier device and the output electrode of the second amplifier device;

wherein

an antenna is connectable to an output terminal of the output matching circuit.

5. The power amplifier according to claim 4, wherein

the first switch circuit includes a first switch device connected between the input electrode of the first amplifier device and the input electrode of the second amplifier device;

and

the first switch device of the first switch circuit is switched on in response to the power mode signal at the first voltage level while the first switch device of the first switch circuit is switched off in response to the power mode signal at the second voltage level.

6. The power amplifier according to claim 5, wherein the first switch circuit further includes a discharging element connected between the input electrode of the second amplifier device and the ground potential.

7. The power amplifier according to claim 5, wherein the second switch circuit includes a second switch device connected between the one end and the other end of the second switch circuit, and the second switch device is switched on in response to the power mode signal at the first voltage level while the second switch device is switched off in response to the power mode signal at the second voltage level.

8. The power amplifier according to claim 4, wherein the one end of the impedance adjusting circuit is connected to the input terminal of the output matching circuit.

9. The power amplifier according to claim 4, wherein the one end of the impedance adjusting circuit is connected to the output terminal of the output matching circuit.

10. The power amplifier according to claim 4, wherein

the output matching circuit includes an intermediate node between the input terminal and the output terminal of the output matching circuit;

and

the one end of the impedance adjusting circuit is connected to a connection node between the input terminal and the intermediate node of the output matching circuit.

11. The power amplifier according to claim 4, wherein

the output matching circuit includes an intermediate node between the input terminal and the output terminal of the output matching circuit;

and

the one end of the impedance matching circuit is connected to another connection node between the intermediate node and the output terminal of the output matching circuit.

12. The power amplifier according to claim 4, further comprising:

another amplifier device defining a bias device connected to the input electrode of the first amplifier device and the input electrode of the second amplifier device;

wherein

a common electrode of the other amplifier device is connected to the ground potential and an input electrode and an output electrode of the other amplifier device are connected to the input electrode of the first amplifier device and the input electrode of the second amplifier device.

13. The power amplifier according to claim 12, wherein the first amplifier device, the second amplifier device, and the other amplifier device are MOS transistors or bipolar transistors.

14. An operation method for a power amplifier that includes an RF signal input terminal, a first amplifier device, a second amplifier device, a load device, a first switch circuit, a second switch circuit, and an impedance adjusting circuit, wherein a common electrode of the first amplifier device and a common electrode of the second amplifier device are connected to a ground potential, and an output electrode of the first amplifier device and an output electrode of the second amplifier device are connected to the load device, the operation method comprising:

supplying an RF input signal of the RF signal input terminal to an input electrode of the first amplifier device and to an input electrode of the second amplifier device in response to a power mode signal at a first voltage level, using the first switch circuit, and performing parallel amplification operations on the RF input signal, using the first amplifier device and the second amplifier device; and

supplying the RF input signal of the RF signal input terminal to the input electrode of the first amplifier device and substantially stopping supplying of the RF signal to the input electrode of the second amplifier device in response to the power mode signal at a second voltage level different from the first voltage level, using the first switch circuit, and performing a stand-alone amplification operation on the RF input signal, using the first amplifier device;

wherein

one end of the impedance adjusting circuit is connected to a connection node between the output electrode of the first amplifier device and the output electrode of the second amplifier device, the other end of the impedance adjusting circuit is connected to one end of the second switch circuit, and the other end of the second switch circuit is connected to the ground potential; and

the impedance adjusting circuit includes a reactance element connected between the one end and the other end of the impedance adjusting circuit;

the operation method further comprising;

causing the one end and the other end of the second switch circuit to be electrically disconnected from each other in response to the power mode signal at the second voltage level and causing the one end and the other end of the second switch circuit to be electrically connected to each other in response to the power mode signal at the first voltage level, using the second switch circuit.

15. The operation method for the power amplifier power amplifier according to claim 14, wherein

the reactance element connected between the one end and the other end of the impedance adjusting circuit includes a capacitive reactance element;

the reactance element connected between the one end and the other end of the impedance adjusting circuit includes an inductive reactance element connected in series with the capacitive reactance element;

the power amplifier further includes an output matching circuit whose input terminal is connected to the output electrode of the first amplifier device and the output electrode of the second amplifier device; and

an antenna is connectable to an output terminal of the output matching circuit.

16. The operation method for the power amplifier power amplifier according to claim 15, wherein

the first switch circuit includes a first switch device connected between the input electrode of the first amplifier device and the input electrode of the second amplifier device;

and

the first switch device of the first switch circuit is switched on in response to the power mode signal at the first voltage level while the first switch device of the first switch circuit is switched off in response to the power mode signal at the second voltage level.

17. The operation method for the power amplifier power amplifier according to claim 16, wherein the first switch device further includes a discharging element connected between the input electrode of the second amplifier device and the ground potential.

18. The operation method for the power amplifier power amplifier according to claim 16, wherein the second switch circuit includes a second switch device connected between the one end and the other end of the second switch circuit, and the second switch device is switched on in response to the power mode signal at the first voltage level while the second switch device is switched off in response to the power mode signal at the second voltage level.

19. The operation method for the power amplifier according to claim 15, wherein the one end of the impedance adjusting circuit is connected to the input terminal of the output matching circuit.

20. The operation method for the power amplifier according to claim 15, wherein the one end of the impedance adjusting circuit is connected to the output terminal of the output matching circuit.