TW201228254A - Radio-frequency front end circuit - Google Patents

Abstract

A radio-frequency front end circuit includes a GSM antenna switch, a multiband antenna, a duplexer and a switch. The GSM antenna switch is coupled to a receiving circuit and a transmitting circuit for receiving or transmitting GSM radio-frequency signal. The duplexer is coupled to a receiving circuit and a transmitting circuit for receiving or transmitting CDMA or WCDMA radio-frequency signals. The switch is coupled to the GSM antenna switch, the duplexer and the multiband antenna. The GSM antenna switch and the duplexer can be alternatively coupled to the multiband antenna by operating the switch.

Description

201228254 VI. Description of the Invention: [Technical Field] The present invention relates to a radio frequency front end circuit, and more particularly to a radio frequency front end circuit applied to a dual mode system. [Prior Art] [0002] Currently, the frequency bands used in the mobile communication are mainly Global System for Mobile Communications (GSM) 850/900/1800/1900 and Universal Mobile Telecommunications System (Universal Mobile Telecommunications System.: . . . UMTS) 850/190.0./^.1:0...0 with the development of mobile communication technology. .......:. 'Multi-mode multi-frequency mobile phones have gradually entered the consumer's sight . The design of the RF front-end circuit is the key to multi-mode multi-band mobile phones. RF front-end circuits typically include antenna switches, power amplifiers, filters, and antennas. The antenna switch is connected to the antenna. By switching the antenna switch, the mobile telephone system can use different frequency bands to transmit and receive signals. [〇〇〇3] The conventional multimode antenna switch is an integrated chip that can switch between multiple GSM bands and multiple UMTS bands. At present, most multimode antenna switches are provided with at least three UMTS band channels, while UMTS in mainland China only uses 800 MHz Code Division Multiple Access (CDMA) and 2100 MHz wideband code division multiple access ( Wideband Code Division Multiple

Access, WCDMA), in the actual use of multi-mode multi-band mobile phones, generally only one of the UMTS bands is used, that is, the above-mentioned multimode antenna switch is generally used only in one of the UMTS band channels during actual use. And the waste of the remaining UMTS band channels, from 099144850 Form No. A0101 Page 4 / Total 13 Page 0992077429-0 201228254 is not conducive to saving manufacturing costs. SUMMARY OF THE INVENTION [0004] In view of this, it is necessary to provide a radio frequency front-end circuit that is low in cost and capable of multi-mode switching. [0005] A radio frequency front end circuit 'includes a GSM antenna switch for transmitting and receiving

a multimode antenna, a duplexer and a switch of a radio frequency signal, the GSM antenna switch being coupled to a receiving circuit and a transmitting circuit of a GSM radio frequency signal, the duplexer being coupled to a receiving circuit of one of a CDMA or WCDMA radio frequency signal And a switching circuit coupled to the GSM antenna switch, the duplexer, and the multimode antenna, by controlling the switching of the switch to selectively couple the GSM antenna switch or duplexer to the Multimode antenna. [〇〇〇6] The RF front-end circuit achieves switching between the GSM system and the CDMA or WCDMA system by using a combination of a GSM twist switch and a switch, compared to the conventional multimode antenna switch. Low manufacturing costs while avoiding waste of the frequency band channels of conventional multimode antenna switches. [Embodiment] 0007 [0007] Please refer to FIG. 1 'The RF front end circuit 10 of the preferred embodiment of the present invention includes a GSM antenna switch 11, a switch 12, a duplexer 13, a multimode antenna 14, a first filter 15, The first power amplifier 16, the second power amplifier 17, the second filter 18, and the central processing unit 19. The GSM antenna switch 11 is coupled to the receiving circuit (not shown) of the GSM radio frequency signal by the first filter 15; and is coupled to the transmitting circuit of the GSM radio frequency signal by the first power amplifier 16 (not shown) Show). The duplexer 13 is coupled to a receiving circuit (not shown) of the CDMA radio frequency signal by the second filter 18; and coupled to the CDMA radio frequency 099144850 form number A0101 by the second power amplifier 17 5 pages / total 13 pages 0992077429-0 201228254 Signal transmission circuit (not shown). The switch 12 is respectively coupled to the GSM antenna switch 11, the duplexer 13, the multimode antenna 14 and the central processor 19'. The central processor 19 controls the switching of the switch 12 to implement GSM. Switching to the CDMA system. In the preferred embodiment, the GSM antenna switch 11 can implement the transmission and reception of four frequency band signals of the GSM850/900/1800/1900. The GSM antenna switch 11 is a single-pole six-throw switch. The GSM antenna switch 11 includes an antenna connection pin 111, four signal reception pins 112, two signal transmission pins 11 3 and three control pins 114. The antenna connection pin 111 is coupled to the changeover switch 12. The four signal receiving pins 112 are G900RX, G180_X, G850RX, and G1 900RX pins, respectively. Each of the signal receiving pins 112 is coupled to one of the first filters 15. The G900RX pin, the G1800RX pin, the G850RX pin, and the G1 900RX pin are respectively used to transmit the signals of the 900 MHz band, the 1 800 MHz band, the 850 MHz band, and the 1 900 MHz frequency Ik received from the multimode antenna 14 to the first A filter 15. The two signal transmitting pins 113 are G850/900TX pins and G1800/1900TX pins, respectively. Each of the signal transmitting pins 113 is coupled to one of the first power amplifiers 16. The G850/900TX pin is configured to receive a signal transmitted by the first power amplifier 16 in the 850 MHz band and the 900 MHz band; the G1 800/1 900ΤΧ pin is used to receive the 1800 MHz band transmitted by the first power amplifier 16 and Signal in the 900MHz band. The three control pins 114 are coupled to the central processing unit 19, and the central processing unit 19 selects the four signal receiving pins 112 and the two signal transmitting pins 113. 099144850 Form No. A0I01 Page 6 One of the three pages 0992077429-0 201228254 is connected to the antenna connection pin 111 to control the transmission and reception of the four frequency band signals of the GSM850/900/1800/1900. [0009] The switch 12 is used to couple one of the GSM antenna switch 11 and the duplexer 13 to the multimode antenna 14. In the preferred embodiment, the switch 12 is a single pole double throw switch. The switch 12 includes a switching end 121, a first connecting end 122, a second connecting end 123, and a control end 124. The switching end 121 is coupled to the multimode antenna 14; the first connection end 122 is coupled to an antenna connection pin in of the GSM antenna switch 11; the second connection end 123 is coupled to the dual 1 The control terminal 124 is coupled to the central processor 19. It is described that the switching terminal 121 is switched to the first connection terminal I2f or the second connection terminal 123 under the control of the central processing unit 19, so that the multimode antenna 14 can be connected to the GS Μ antenna switch 11 or duplex. 13. [0010] The duplexer 13 includes an antenna terminal, a terminal, and a receiving end. The antenna terminal ANT is coupled to the second connection end 123 of the changeover switch 12; the transmit end TX__ is consuming to the second liquid wave device 18; the receive end RX is coupled to the second filter 18. The duplexer 13 can simultaneously receive and transmit CDMA RF signals, and can ensure a certain degree of isolation to prevent mutual crosstalk between the received signals and the transmitted signals. The first chopper 15 is configured to filter the g § Μ RF signal received from the multimode antenna 14, that is, filter out the clutter outside the corresponding frequency band, and then transmit the chopped GSM RF signal to The GSM RF signal receiving circuit 099144850 Form No. 1010101 0992077429-0 [0011] [0012] [0013] The first power amplifier 16 will receive the modulated GSM RF signal from the GSM RF signal transmitting circuit. The power is amplified to meet the transmission power requirement and transmitted through the multimode antenna 14. The second filter 18 is configured to filter the CD Μ A RF signal received from the multimode antenna 14 , that is, filter out the clutter outside the corresponding frequency band, and then transmit the filtered CDMA RF signal to The receiving circuit of the CDMA radio frequency signal. [0017] [0017] 099144850 The second power amplifier 17 is configured to perform power amplification on the modulated CDMA RF signal received from the transmitting circuit of the CDMA radio frequency signal to meet the requirement of satisfying the transmission power. And transmitted through the multimode antenna 14. It can be understood that, since both CDMA and WCDMA are signal transmission modes using code division multiple access, the duplexer 13 can also be coupled to the receiving circuit of the WCDMA radio frequency signal by the second filter 18 (not shown). And coupled to the transmitting circuit (not shown) of the WCDMA radio frequency signal by the second power amplifier 17. The multi-mode line 14 and the duplexer 13 can also jointly implement transmission and reception of WCDMA radio frequency signals. That is, the radio frequency front end circuit 1 of the present invention can also realize the switching between the G S Μ and WC D Μ A systems. It can be understood that the GSM antenna switch can also be a single pole four throw switch, such as the GSM dual frequency antenna switch of the model CXG1121TN by Sony Corporation. It can be understood that the GSM antenna switch can also be a single-pole, five-throw switch, such as the LMPS33CA GSM tri-band antenna switch of Murray. The RF front-end circuit 1 is implemented between the GSM system and the CDMA or WCDMA system by using the combination of the GSM antenna switch 11 and the switch-opening form number A0101, page 8/13, 0992077429-0 [0018] 201228254. The switching has a lower manufacturing cost compared to the conventional multimode antenna switch, and at the same time avoids wasting the band channel of the conventional multimode antenna switch. [0023] [0023] [0023] [0023] [0024] [0028] [0030] [0030] In summary, the present invention meets the requirements of the invention patent,提出 Submit a patent application in accordance with the law. However, the above-mentioned embodiments are only the embodiments of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be equivalently modified or changed in the spirit of the invention. It is included in the scope of the following patent application. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the structure of a radio frequency front end circuit according to a preferred embodiment of the present invention. [Main component symbol description] RF front-end circuit: 10 GSM antenna switch: 11 antenna connection pin: 111 signal receiving pin: 112 signal transmission pin: 113 control pin: 114 switch: 12 switch end: 121 first connection End: 122 Second connection: 123 099144850 Form number A0101 Page 9 / Total 13 page 0992077429-0 201228254

Control terminal: 124 [0032] Duplexer: 13 [0033] Multimode antenna: 14 [0034] First filter: 15 [0035] First power amplifier: 16 [0036] Second power amplifier: 17 [0037] Second filter: 18 [0038] Central processing unit: 19 [0039] Antenna terminal: ANT [0040] Transmitter: TX [0041] Receiver: RX 099144850 Form number A0101 Page 10 of 13 0992077429 -0

Claims (1)

201228254 VII. Patent application scope: • 1. An RF front-end circuit comprising a GSM antenna switch and a multimode antenna for transmitting and receiving a wireless RF signal, the GSM antenna switch being coupled to a receiving circuit and a transmitting circuit of the GSM RF signal, The improvement is that the RF front-end circuit further includes a duplexer and a switch, the duplexer being coupled to a receiving circuit and a transmitting circuit of one of a CDMA or WCDMA RF signal, the switching switch being coupled to the GSM antenna switch And a duplexer and a multimode antenna, selectively coupling the GSM antenna switch or duplexer to the multimode antenna by controlling switching of the switch. 2. The RF front-end circuit of claim 1, wherein the switch is a single-pole double-throw switch. 3. The RF front-end circuit of claim 1 or 2, wherein the RF front-end circuit is coupled to a central processor that controls switching of the switch. 4. The RF front-end circuit of claim 1 or 2, wherein the GSM antenna switch is a single-pole six-throw switch, a single-pole four-throw switch, or a single-pole five-throw switch. 5. The RF front-end circuit of claim 4, wherein the GSM antenna switch comprises a plurality of signal receiving pins, at least one signal transmitting pin, and an antenna connecting pin, each of the signal receiving The pins are coupled to a filter, each of the signal transmit pins being coupled to a power amplifier, the antenna connection pins being coupled to the switch. 6. The radio frequency front end circuit of claim 1 or 2, wherein the duplexer comprises an antenna end, a transmitting end, and a receiving end, the radio frequency front end circuit further comprising a second filter and a second power amplifier The antenna end is coupled to 099144850 Form Number Α 0101 Page 11 / Total 13 Page 0992077429-0 201228254 The switching switch is coupled to the second power amplifier, the receiving end being coupled to the second filter. 099144850 Form No. A0101 Page 12 of 13 0992077429-0