POWER AMPLIFIER CIRCUIT

• US 20170359038A1
• Filed: 05/22/2017
• Published: 12/14/2017
• Est. Priority Date: 06/14/2016
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: TANAKA, Satoshi, WATANABE, Kazuo, TSUTSUI, Takayuki, KONDO, Masao, ARAYASHIKI, Satoshi, HARIMA, Fumio, HASE, Masatoshi
• Granted Patent: US 10,177,724 B2
• Time in Patent Office: Days
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/0272 by using a signal derived from the output signal
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 1/22 by use of cascode coupling, i.e. earthed cathode or emitter stage followed by earthed grid or base stage respectively
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/222 A circuit being added at the input of an amplifier to adapt the input impedance of the amplifier
• CPC Class Codes: H03F 2200/318 A matching circuit being used as coupling element between two amplifying stages
• 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 2200/408 the output amplifying stage of an amplifier comprising three power stages
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/555 A voltage generating circuit being realised for biasing different circuit elements
• CPC Class Codes: H03F 3/005 using switched capacitors, e.g. dynamic amplifiers; using switched capacitors as resistors in differential amplifiers H03F3/45 takes precedence
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/21 with semiconductor devices only H03F3/245 takes precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 88/00 Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices

Abstract

A power amplifier circuit includes first and second transistors and a first voltage output circuit. A radio frequency signal is input into a base of the first transistor. The first voltage output circuit outputs a first voltage in accordance with a power supply voltage. The first voltage is supplied to a base or a gate of the second transistor. An emitter or a source of the second transistor is connected to a collector of the first transistor. A first amplified signal generated by amplifying the radio frequency signal is output from a collector or a drain of the second transistor.

Claims

1. A power amplifier circuit comprising:

a first transistor, a radio frequency signal being input into a base of the first transistor;

a first voltage output circuit configured to output a first voltage in accordance with a power supply voltage; and

a second transistor, wherein;

the first voltage is supplied to a base or a gate of the second transistor,

an emitter or a source of the second transistor is connected to a collector of the first transistor, and

a first amplified signal generated by amplifying the radio frequency signal is output from a collector or a drain of the second transistor.

2. The power amplifier circuit according to claim 1, wherein the first voltage output circuit comprises a limiter circuit that controls the first voltage at or above a predetermined level so as to turn ON the second transistor.

3. The power amplifier circuit according to claim 2, wherein the first voltage output circuit further comprises a first resistor and a second resistor, the first resistor and the second resistor being connected in series with each other, and wherein the first voltage is output from a node between the first resistor and the second resistor.

4. The power amplifier circuit according to claim 3, wherein the limiter circuit comprises a diode connected to ground in series with the first resistor and the second resistor.

5. The power amplifier circuit according to claim 4, wherein the limiter circuit further comprises a first capacitor disposed between an anode of the diode and ground.

6. The power amplifier circuit according to claim 4, wherein the limiter circuit further comprises a third transistor configured to cause a current to flow through the first resistor and the second resistor based on a control signal that turns ON the third transistor.

7. The power amplifier circuit according to claim 6, wherein the limiter circuit further comprises a current output circuit configured to supply a first current to the anode of the diode based on the control signal that turns ON the third transistor.

8. The power amplifier circuit according to claim 7, wherein the current output circuit comprises a fourth transistor that is turned ON when the control signal turns ON the third transistor and that outputs the first current from an emitter of the fourth transistor so as to turn ON the diode.

9. The power amplifier circuit according to claim 3, wherein the first voltage output circuit further comprises a third resistor and a second capacitor, and wherein the third resistor and the second capacitor are connected in series between ground and a node between the first resistor and the second resistor.

10. The power amplifier circuit according to claim 1, further comprising:

a fifth transistor, the radio frequency signal being input into a base of the fifth transistor, an emitter of the fifth transistor being grounded, and the first amplified signal being output from a collector of the fifth transistor;

a first bias circuit configured to supply a first bias current or voltage to the base of the first transistor;

a second bias circuit configured to supply a second bias current or voltage to the base of the fifth transistor; and

a switch circuit configured to stop supply of the first bias current or voltage when a value of the power supply voltage is a first level, and configured to stop supply of the second bias current or voltage when the value of the power supply voltage is a second level,

wherein the second level is higher than the first level.

11. The power amplifier circuit according to claim 1, further comprising:

a sixth transistor, the first amplified signal being input into a base of the sixth transistor;

a second voltage output circuit configured to output a second voltage in accordance with the power supply voltage; and

a seventh transistor, wherein;

the second voltage is supplied to a base or a gate of the seventh transistor,

an emitter or a source of the seventh transistor is connected to a collector of the sixth transistor, and

a second amplified signal generated by amplifying the first amplified signal is output from a collector or a drain of the seventh transistor.

12. The power amplifier circuit according to claim 11, wherein the sixth transistor is a bipolar transistor and the seventh transistor is a field-effect transistor.

13. The power amplifier circuit according to claim 12, wherein the seventh transistor is a depletion field-effect transistor having a threshold voltage of 0 V or lower.

14. The power amplifier circuit according to claim 1, wherein the first transistor is a bipolar transistor and the second transistor is a field-effect transistor.

15. The power amplifier circuit according to claim 14, wherein the second transistor is a depletion field-effect transistor having a threshold voltage of 0 V or lower.

16. The power amplifier circuit according to claim 1, wherein the power supply voltage is generated by a buck-boost DC-to-DC converter.

17. The power amplifier circuit according to claim 2,

further comprising an inductor, a first end of the inductor being connected to the power supply voltage and a second end of the inductor being connected to the collector or the drain of the second transistor, and

wherein the first resistor is connected to the second end of the inductor.

18. The power amplifier circuit according to claim 2,

further comprising an inductor, a first end of the inductor being connected to the power supply voltage and a second end of the inductor being connected to the collector or the drain of the second transistor, and

wherein the first resistor is connected to the first end of the inductor.

19. The power amplifier circuit according to claim 3, wherein the limiter circuit comprises:

a fourth resistor connected to ground in series with the first resistor and the second resistor;

a third capacitor disposed between ground and a node between the second resistor and the fourth resistor; and

a current output circuit configured to supply a first current to the node between the second resistor and the fourth resistor.

20. The power amplifier circuit according to claim 1, further comprising:

a fifth transistor, the radio frequency signal being input into a base of the fifth transistor, an emitter of the fifth transistor being grounded, and the first amplified signal being output from a collector of the fifth transistor; and

a switch circuit configured to ground the base of the first transistor when a value of the power supply voltage is a first level, and configured to ground the base of the fifth transistor when the value of the power supply voltage is a second level,

wherein the second level is higher than the first level.