Power amplifier matching in dual band mobile phone

• US 6,317,608 B1
• Filed: 11/21/2000
• Issued: 11/13/2001
• Est. Priority Date: 05/22/1998
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Glöcker, Romàn
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): PEREZ GUTIERREZ, RAFAEL
• Application Number:
  US09/716,226
• Time in Patent Office: 357 Days
• Field of Search: 455/82, 455/83, 455/80, 455/81, 455/129, 455/115, 455/78, 455/553, 455/552, 455/180.1, 455/188.1, 455/101, 455/103, 455/127, 333/101, 333/124, 333/129, 333/132, 333/125, 333/126, 333/32, 330/126, 330/129, 330/124.R, 330/51
• US Class Current: 455/553.1
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/44 Transmit/receive switching

Abstract

To achieve an improved matching of a power amplifier to transmission line impedances of different transmission branches in a dual band mobile phone there is proposed a new power amplifier output circuit for such a dual band mobile phone. This power amplifier output circuit comprises a transmission branch change over unit being connected to an output terminal of the power amplifier. Further, there is provided a second impedance matching means in at least one transmission branch and the transmission branch change over unit comprises at least two switching elements between the first impedance matching unit and the second impedance matching unit. Therefore, the disturbing influence of parasitic elements in the switching elements may be reduced significantly.

Claims

1. A power amplifier output circuit for a dual band mobile radio unit, comprising:

a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,

a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,

a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, wherein

a second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit,

the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit,

a third impedance matching unit is provided at an input terminal of said second transmitter/receiver change over means, and

a switchable band stop filter is provided downstream said third impedance matching means that filters harmonics of said first transmitting signal in said second transmission branch during the transmission of said first transmitting signal.

2. A power amplifier output circuit for a dual band mobile radio unit, comprising:

a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,

a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,

a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, wherein

a second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit,

the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit,

a third impedance matching unit is provided at an input terminal of said second transmitter/receiver change over means, and

said transmission branch change over unit is realized with a third diode of said PIN-type between said second impedance matching unit and said third impedance matching unit.

3. The power amplifier output circuit of claim 2, wherein said first impedance matching unit is provided with a first capacitor at an input thereof, said first capacitor being connected in Shunt-configuration.

4. The power amplifier output circuit of claim 3, wherein a second capacitor is connected in series between said input of said first impedance matching unit and an output of said first impedance matching unit.

5. The power amplifier output circuit of claim 4, wherein an inductivity is connected across said second capacitor.

6. A power amplifier output circuit for a dual band mobile radio unit, comprising:

a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,

a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,

a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, wherein

a second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit,

the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit,

a third impedance matching unit is provided at an input terminal of said second transmitter/receiver change over unit, and

a second line element is provided between an input and an output of said third impedance matching means and a third line element is connected in series to said second line element in said third impedance matching unit.

7. The power amplifier output circuit of claim 6, wherein a fourth capacitor branches off to ground at a connection point between said second line element and said third line element.

8. A power amplifier output circuit for a dual band mobile radio unit, comprising:

a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,

a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,

a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, wherein

a second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit,

the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit, and

said transmission branch change over unit is realized with a first diode of the PIN-type and a second diode of the PIN-type between said first impedance matching unit and said second impedance matching unit such that first diode of the PIN-type and said second of the PIN-type are connected in parallel.

9. The power amplifier output circuit of claim 8, wherein said first diode of the PIN-type and said second diode of said PIN-type (46) are accommodated in a single package.

10. A power amplifier output circuit for a dual band mobile radio unit, comprising:

a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,

a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,

a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, wherein

a second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit,

the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit, and

a low pass filter is provided between said first impedance matching unit and said first transmitter/receiver change over unit for the filtering harmonics of said first transmitting signal.

11. A power amplifier output circuit for a dual band mobile radio unit, comprising:

a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,

a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,

a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, wherein

a second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit, and

the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit, wherein

a first line element is provided at an input of said second impedance matching unit.

12. The power amplifier output circuit of claim 11, wherein at an end of said first line element lying at an output side a third capacitor is connected to ground.

13. A power amplifier output circuit for a dual band mobile radio unit, comprising:

a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,

a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,

a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, wherein

a second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit, and

the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit.

14. The power amplifier output circuit of claim 13, which comprises a third impedance matching unit at an input terminal of said second transmitter/receiver change over unit.

15. The power amplifier output circuit of claim 14, wherein said transmission branch change over unit comprises at least one switching element between said second impedance matching unit and said third impedance matching unit.