Mobile telephone apparatus

• US 20020082045A1
• Filed: 02/05/2002
• Published: 06/27/2002
• Est. Priority Date: 10/26/2000
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Sekine, Kenji, Kagaya, Osamu, Yoshida, Isao, Fujioka, Toru, Morikawa, Masatoshi, Matsunaga, Yoshikuni, Katsueda, Mineo
• Granted Patent: US 6,865,399 B2
• Time in Patent Office: Days
• US Class Current: 455/553.1
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• 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 2200/18 the bias of the gate of a FET being controlled by a control signal
• 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 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/405 the output amplifying stage of an amplifier comprising more than three power stages
• 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 2203/7209 the gated amplifier being switched from a first band to a second band
• CPC Class Codes: H03F 2203/7221 the gated amplifier being switched on or off by a switch at the output of the amplifier
• CPC Class Codes: H03F 3/195 in integrated circuits
• 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
• 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 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

In a mobile telephone apparatus corresponding to dual-band provided with an RF power module to operate in two kinds of different frequencies, a common harmonics control circuit is provided to the output circuit of such RF power module to realize higher efficiency in view of controlling respective harmonics power for both band frequencies. Moreover, a means for selectively setting the bias is also provided so that the maximum efficiency can be attained depending on the output power required with respective communication systems with the bias control signal output from the CPU of the control unit interlocking with selection of frequency of the mobile telephone apparatus body. In addition, a switching element is also provided to such harmonics control circuit to enable the harmonics control without giving any influence on the radio frequency signal of each communication system.

With the structure explained above, it is possible to realize the small size and high efficiency mobile telephone apparatus corresponding to the dual frequency bands.

Claims

1. A dual-band type mobile telephone apparatus that can transmit and receive the band frequencies of the first and second radio frequency signals in different frequencies, comprising:

a frequency selection switch provided on said apparatus body to select said first and second radio frequency signals;

a driver amplifier having the frequency characteristic tuned with both frequency bands of said first and second radio frequency signals;

a first RF power module for amplifying, with the first power transistor, the power of the first radio frequency signal amplified with said driver amplifier and then outputting the amplified signal to an antenna;

a second RF power module for amplifying, with the second power transistor, the power of the second radio frequency signal amplified with said driver amplifier and then outputting the amplified signal to an antenna;

a control unit interlocked with said frequency selection switch to output first and second bias control signals for selectively switching the operating condition of said first and second power transistors;

first and second switching elements respectively connected in series in the input side of said first and second power transistors to be selected to conductive/non-conductive conditions interlocking with said first and second bias control signals; and

a harmonics control circuit used in common for said first and second radio frequency signals that is set so that the drain ends of said first and second power transistors terminate, interlocking with said first and second bias control signal, for the even number order harmonics of said first and second radio frequency signals or opens for the odd number order harmonics of the radio frequency signals.

2. A mobile telephone apparatus according to claim 1, wherein said first and second power transistors are comprised of a plurality of parallel connected unit MOSFETs and the first power transistor and second power transistor have different gate width.

3. A mobile telephone apparatus according to claim 2, wherein said first and second power transistors and said first and second switching elements are provided within one RF power module in place of using said first and second RF power modules.

4. A mobile telephone apparatus according to claim 3, wherein said RF power module is formed on the same semiconductor substrate.

5. A mobile telephone apparatus according to any one of the claims 1 to 4, wherein said harmonics control circuit is comprised of:

first and second transmission lines in the length corresponding to ⅛

wavelength of a first radio frequency signal provided between the drain end of said first power transistor and the drain end of said second power transistor;

a first DC rejection capacitor connected between said first and second transmission lines;

a first switching element that is inserted via a second DC rejection capacitor between a ground and one end of the second transmission line connected to the drain end side of said second power transistor to become conductive for the first radio frequency signal; and

second switching element that is inserted via the third DC rejection capacitor between the ground and the other end of said second transmission line to become conductive for the second radio frequency signal.

6. A mobile telephone apparatus according to any one of the claims 1 to 5, wherein the frequency of said first radio frequency signal is equal to ½

the frequency of said second radio frequency signal.

7. A mobile telephone apparatus according to any one of the claims 1 to 6, wherein said first and second switching elements are formed of FET switches.