KR20010017454A - Radio-frequency power amplifier of mobile communication equipment - Google Patents

Abstract

PURPOSE: An RF power amplifier for mobile communication system is provided to improve a quality of a transmitting signal and reduce the power consumption. CONSTITUTION: An input portion is formed with one or more a differential amplifier(11,12,13). The input portion receives and amplifies a high frequency signal outputted from a frequency converter of a mobile communication system. A plurality of bias current circuit(15,16,17) provides a variable bias current corresponding to a gain control signal of the differential amplifier(11,12,13) and sets up variably a gain of the differential amplifier(11,12,13). A high frequency grounding pattern is formed on a substrate of the mobile system.

Description

RF power amplifier for mobile communication equipment {RADIO-FREQUENCY POWER AMPLIFIER OF MOBILE COMMUNICATION EQUIPMENT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to radio frequency (RF) power amplifiers, and more particularly to RF power amplifiers for portable mobile stations capable of improving the quality of a transmission signal and reducing power consumption.

BACKGROUND OF THE INVENTION [0002] BACKGROUND OF THE INVENTION [0002] A mobile communication system for performing communication by radio frequency between a radio base station and a mobile station arranged at regular intervals in a service area has been widely used. Such a communication system is constructed in various ways depending on the purpose of use. For example, in a land mobile communication system using a public telephone network, a mobile station is realized as a mobile phone or a mobile phone, and is publicly communicated through each wireless base station and a radio line control station. Access to the telephone network is possible.

A typical type of mobile phone commonly used in accordance with the prior art has a device body including a transmission and reception system, the device body is composed of a telephone and an antenna including a handset and a battery as a power source.

The transmitter circuit of the cellular phone according to the prior art includes an acoustic electric converter, a modulator, a frequency converter, and an RF power amplifier, and converts the voice input to the transmission system through a transmitter to an acoustic electric signal. It is transmitted as a radio wave through the process of modulation, frequency conversion and power amplification.

However, RF power amplifiers according to the prior art are often composed of a single-end type circuit having a proven track record in a hybrid IC, and the power amplifier is a mobile device main body. The circuit board is mounted on a circuit board and connected to a high frequency ground pattern of the circuit board.

The RF power amplifier according to the related art configured as described above is easily influenced by the amplification factor and the distortion factor of the power amplifier under the influence of the high frequency ground pattern, resulting in a deterioration of the quality of the transmission signal.

In the case of land mobile communication of the CDA system, it is preferable that the electric field strengths of radio waves transmitted from all mobile devices sharing the same frequency are the same at the wireless base station. Therefore, the mobile device is adapted to adjust the transmission output power in response to the transmission power control signal (gain control signal) transmitted from the radio base station.

BACKGROUND ART [0002] A conventional mobile phone in which an RF power amplifier of a transmission system is constituted by a single-ended circuit has a gain in an automatic gain control (AGC) circuit formed between a modulator and a frequency changer in front of the RF power amplifier. The transmission output is adjusted by applying a control signal.

That is, in mobile phones, transmission output adjustment is generally not performed by gain adjustment of an RF power amplifier configured as a single-ended circuit, which is used to change the bias current applied to the same circuit to change the amplification gain of the single-ended circuit. If it is changed, abnormal operation such as oscillation phenomenon is likely to occur in single-ended circuit.

Therefore, the RF power amplifier of the cellular phone according to the prior art is configured to perform an amplification operation at a fixed gain ratio, whereby the power efficiency of the RF power amplifier is lowered especially when the level of the transmission output is low. On the other hand, the power consumption of RF power amplifiers during transmission accounts for a large proportion of the total power consumed by mobile devices.

Therefore, in order to efficiently manage the power consumption of RF power amplifiers which are frequently used at low output power levels in portable mobile phones, an RF power amplifier having good power efficiency characteristics is required.

Accordingly, it is a first object of the present invention to provide an RF power amplifier which does not cause a deterioration of the transmission signal due to the influence of the high frequency ground pattern of the circuit board in the mobile device for wireless communication.

A second object of the present invention is to provide an RF power amplifier having a good power efficiency in a region having a low transmission output level in addition to the first object.

A third object of the present invention is to provide an RF power amplifier for a mobile device which can control the amplification gain in a simple and stable manner in addition to the first object.

A fourth object of the present invention is to provide a mobile device capable of miniaturizing a high frequency module configured by mounting an RF power amplifier on a circuit board, which comprises a high frequency part of a transmission system of a mobile device together with a modulator and a frequency converter. To provide an RF power amplifier.

1 is a block diagram showing the configuration of a W-CDMA mobile telephone mounted with an RF power amplifier according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of an RF power amplifier module constituting the RF power amplifier shown in FIG.

3 is a circuit diagram illustrating the circuit configuration of the RF power amplifier module shown in FIG.

Fig. 4 is a diagram showing the relationship between the transmission power and the power efficiency in the RF power amplifier module shown in Figs. 2 and 3 in comparison with the characteristics of the RF power amplifier according to the prior art.

Fig. 5 is a diagram showing the relationship between the range of transmission power levels and the frequency of use of each transmission power level in the mobile telephone.

6 is a block diagram showing another embodiment of an RF power amplifier according to the present invention;

Figure 7 is a block diagram showing another embodiment of an RF power amplifier according to the present invention.

<Explanation of symbols for main parts of drawing>

1: antenna

2: RF section

2r: receiver section

2t: transmitter section

3: base band section

100: wireless base station

The RF power amplifier for a mobile device according to the first embodiment of the present invention comprises at least one differential amplifier which balances and amplifies a high frequency signal output from a frequency converter disposed behind a modulation section of a transmission system of the mobile device. An input terminal; And a bias current circuit that variably sets the gain of the differential amplifier by supplying a bias current that changes in response to a gain control signal to the differential amplifier, wherein the RF power amplifier is mounted on a circuit board of the mobile device and is mounted on the circuit board. Is formed in a high frequency ground pattern.

As a preferred embodiment of the RF power amplifier according to the present invention, the input terminal of the RF power amplifier is composed of a plurality of differential amplifiers directly coupled to each other, and the aforementioned bias current circuit is supplied to each of the plurality of differential amplifiers. According to the RF power amplifier according to the present invention, an input configured by a differential amplifier for balanced input of a high frequency signal is virtually grounded to a high frequency ground pattern of a mobile device circuit board on which the power amplifier is mounted.

That is, since the differential amplifier constituting the input terminal of the power amplifier performs the amplification operation in a floating state with respect to the high frequency ground pattern, it is possible to amplify the high frequency signal while maintaining the linearity of the amplifier without being affected by the high frequency ground pattern. In addition, since the amplification gain can be changed by changing the bias current of the differential amplifier in response to the gain control signal, the amplification gain can be set simply and stably.

According to another exemplary embodiment of the present invention, an RF power amplifier for a mobile device includes a push-pull for amplifying and outputting a high frequency signal inputted through an input terminal of an amplifier from a frequency converter disposed at a rear end of a transmission system modulator of the mobile device. an output stage consisting of a push-pull circuit and a bias current circuit for varying the bias current of the push-pull circuit according to a gain control signal, wherein the RF power amplifier is mounted on a circuit board of the mobile device. A high frequency ground pattern is formed.

As a preferred embodiment of the bias current circuit described above, the bias current of the push-pull circuit can be varied by varying the operating current of the constant current circuit connected to each base of the pair of transistors constituting the push-pull circuit. According to the RF power amplifier according to the present invention, an output stage configured as a push-pull circuit balances an amplified high frequency signal and, when mounted on a mobile device circuit board, an amplification operation in a virtual ground state with respect to the high frequency ground pattern of the circuit board. Since it is possible to perform the operation stably without being affected by the high frequency ground pattern.

In addition, by changing the bias current of the push-pull circuit constituting the output stage to the optimum level in response to the gain control signal, the transmission output level can be easily and stably varied. In addition, since the power loss of the RF power amplifier in the low output level region can be reduced, the power efficiency of the RF power amplifier can be improved.

In accordance with still another aspect of the present invention, an RF power amplifier for a mobile device includes at least one differential amplifier configured to equalize and amplify a high frequency signal output from a frequency converter disposed at a rear end of a modulator of a transmission system of a mobile device. A first bias current circuit for supplying a bias current that varies in response to a gain control signal to the at least one differential amplifier to variably set the gain of the differential amplifier, and a high frequency signal amplified by the input stage and output from the input stage; An output stage comprising a push-pull circuit for amplifying and outputting a balanced output, and a second bias current circuit for varying the bias current of the push-pull circuit in response to a gain control signal, wherein the RF power amplifier is connected to a circuit board of the mobile device. It is mounted, and the circuit board is a high frequency contact A pattern is formed.

According to the RF power amplifier having the above constitution, the advantages of the two embodiments described above appear. That is, the RF power amplifier according to the present invention can amplify a high frequency signal while maintaining the linearity of the amplifier without being affected by the high frequency ground pattern. In addition, the transmission output level can be changed easily and stably, and in particular, the power efficiency of the RF power amplifier in the low output level region can be improved.

In a preferred embodiment according to the present invention, the gain control signal is a signal sent from the control unit of the wireless base station or the mobile device to define the transmission output level of the mobile device. As a preferred embodiment of the RF power amplifier according to the present invention, a high frequency module mounted on a circuit board together with a modulator, a frequency converter, and a receiving system of a mobile device may be configured to perform a function as a high frequency part of a mobile device. .

As a preferred embodiment according to the invention, the RF power amplifier can be integrated circuit. Since the modularized high frequency part can reduce the size or reduce the power consumption, a large number of circuit components are required as in a mobile device of a wideband code division multiple access (W-CDMA) system, and at the same time, linearity of transmission power is required. It solves a problem that occurs in configuring a mobile device. In addition, the RF power amplifier according to the present invention improves its versatility by modularizing the high frequency part and can be applied to mobile devices of various specifications.

As a preferred embodiment of the present invention, the integrated circuited RF power amplifier makes it possible to manufacture the power amplifier so that its operational stability is compensated, and thus the mounting conditions of the power amplifier on the circuit board can be relaxed. Therefore, the integrated power amplifier according to the preferred embodiment of the present invention can be more easily modulated with the advantage that the mounting conditions are alleviated with the advantage of being compact.

In a preferred embodiment according to the invention, the RF power amplifier can be mounted in a portable mobile device. The RF power amplifier according to the present invention has a high power efficiency, and as a result is particularly suitable for providing a portable mobile device such as a cellular phone using a battery as a power source.

Best Mode for Carrying Out the Invention Preferred embodiments of the RF power amplifier according to the present invention will now be described in detail with reference to the accompanying drawings, FIGS.

The RF power amplifier according to the present invention constitutes a part of a transmission system of a mobile device, such as a mobile telephone for land mobile object public communication of the W-CDMA (Wideband Code Division Multiple Access) system. Referring to FIG. 1, the cellular phone is provided with an antenna 1, a high frequency part 2, a base band part 3 and a main control part 4. As shown in FIG.

The main control unit 4 includes a microprocessor including a CPU 4a and a ROM 4b and a communication control unit 4c, and is connected to a command signal or a CPU from the wireless base station 100 and can be operated by a user. Based on the instruction from the panel 5, it is possible to automatically set, cut, switch channels, and the like for a radio circuit for telephone communication.

A speaker 6 and a microphone 7 are connected to a voice codec 4d of the main control unit 4. Reference numeral 8 denotes a liquid crystal display for displaying information to the user. The high frequency part 2 is comprised as an RF module in which the transmitter 2t, the receiver 2r, the frequency synthesizer 2s, and the duplex 2d are mounted on the circuit board 2a.

The transmitter 2t has a digital phase shift modulator (4-phase PSK) 201. Regarding the four-phase PSK, the baseband section 3 including the transmission modem 3t is configured to transmit an electrical signal acoustically-converted in the microphone 7 to a voice codec (CODEC) 4d of the main controller 4 and to communicate. Input via the control unit to convert to a baseband signal. The four-phase PSK modulator 201 modulates the carrier baseband signal (voice information) generated by the phase synchronization circuit (PLL) 221.

The carrier modulated from the four-phase PSK modulator 201 is applied to the automatic gain control (AGC) amplifier 203 via a band pass filter (Tx IF BPF) 202. The automatic gain control amplifier 203 amplifies the output of the filter 202 with an amplification degree varying according to the gain control signal from the base station 100 or the main controller 4.

The output of the AGC amplifier 203 is applied to a frequency converter (Up Converter Tx) 204, mixed with the UHF signal from the voltage controlled oscillator (UHF VCO) 222 of the frequency synthesizer 2s and converted into a high frequency signal. This high frequency signal is input to the RF power amplifier 206 via a band pass filter (Tx RF BPF) 205. The RF power amplifier constitutes the main part of the present invention, which will be described later. The high frequency signal amplified by the RF power amplifier 206 is transmitted from the antenna 1 via the duplex 2d.

The receiving unit 2r of the high frequency unit 2 includes a low noise amplifier (LNA) 211 for inputting a high frequency signal received by the antenna 1 via the duplex 2d, and a high frequency signal amplified by the amplifier 211. Is input to a down converter 213 via a band pass filter (RX RF BPF) 212, where it is converted into an intermediate frequency signal IF.

This intermediate frequency signal is input to the four-phase PSK demodulator 216 via a band pass filter (RX IF BPF) 214 and an automatic gain control amplifier (RX AGC AMP) 215 to obtain a baseband signal (voice information). The baseband signal is input to the speaker 6 via the reception modem 3r of the baseband section 3, the communication control unit 4c of the main control section 4, and the voice codec (CODEC) 4d, and is subjected to electroacoustic conversion. It is spoken.

Hereinafter, the RF power amplifier constituting the main part of the present invention will be described in detail with reference to FIG.

The RF power amplifier 206 according to the embodiment of the present invention is a monolithic integrated circuit (hereinafter referred to as a power module 206) which is compact and has operational stability. As already described with reference to Fig. 1, the RF power module 206 is mounted on the circuit board 2a together with the circuit components constituting the transmitter 2t and the circuit components constituting the receiver 2r, and modularized. The high frequency part 2, ie, the high frequency module 2, is comprised.

The RF power module 206 contributes to the miniaturization and operation safety of the high frequency module 2. The RF power module 206 also amplifies the high frequency signal modulated (e.g., 2 Hz) in the four phase PSK modulator (more broadly the RF modulator 201) to a desired gain (e.g., 5 dB, 10 dB or 30 dB), It plays a role of outputting to the antenna 1.

As shown in FIG. 2, the high frequency power module 206 has input stages formed as first and second differential amplifiers 11 and 12 directly connected to each other, and the first differential amplifier 11 is a An input terminal connected to the RF balanced input terminals RF in (+) and RF in (−); 206a and 206b, respectively, is provided for balanced input of a high frequency signal.

In addition, the high frequency power module 206 is connected to an input terminal connected to the output terminal of the second differential amplifier 12 and the RF balanced output terminals RF out (+) and RF out (−); 206c and 206d of the module. And an output stage consisting of a push-pull circuit 13 having an output terminal, the push-pull circuit 13 power amplifying a high frequency signal amplified by the differential amplifiers 11 and 12 to the antenna 1. The balanced output is intended.

The first and second bias current circuits 15 and 16 connected to each of the first and second differential amplifiers 11 and 12 operate by receiving an internal reference voltage V _ref generated by the reference voltage generation circuit 19. In response to the gain control signal from the base station 100 or the main control circuit 4, the bias current of the differential amplifiers 11 and 12 is varied to variably set the amplification gain of the differential amplifier.

In addition, the third bias current circuit 17 connected to the push-pull circuit 13 varies the bias current of the push-pull circuit 13 in response to the gain control signal, thereby causing a large power loss in the push-pull circuit 13. While setting the optimum DC bias current for the cellular phone to generate a desired level of transmission output.

Furthermore, the amplification gain at each stage for the high frequency signal is set at, for example, about 10 dB. In addition, 20 dB of gain control for varying the output (transmission output) of the high frequency signal can be performed by variably adjusting the bias current in the differential amplifier 11 of the first stage.

In Fig. 2, reference numeral 206e denotes a gain control signal input terminal of the RF power module 206, and reference numeral 207 denotes a tuning circuit. The symbol GND represents the ground pattern formed on the circuit board 2a. Moreover, the wiring pattern (not shown) and the high frequency grounding pattern (indicated by the symbol RF GND in Fig. 3) for connecting the circuit components mounted thereon are formed independently of the grounding pattern GND in the circuit board 2a. .

In Fig. 3, the broken line associated with the high frequency ground pattern RF GND represents the virtual ground. More specifically, as shown in Fig. 3, the high frequency power module 206 is mainly composed of a plurality of bipolar transistors T ₁ , T ₂ to T ₁₁ . The first differential amplifier 11 of the high frequency power module mainly consists of a pair of transistors T ₁ and T ₂ , and emitters of both transistors are connected to each other, and load resistors R ₁ and R ₂ are connected to the collector, respectively. It is.

The first differential amplifier 11 composed of the transistors T ₁ and T ₂ is driven by a constant current source formed by the transistor T ₃ , which is formed between the emitters of both transistors and the ground GND, and is the base of the transistors T ₁ and T ₂ . The amplified high frequency signal is input through the capacitor.

The second differential amplifier 12 mainly comprises a pair of transistors T ₄ and T ₅ , and emitters of both transistors are connected to each other, and the base is connected to T ₁ , ₂ of the transistors of the first differential amplifier 11. It is directly connected to the collector of T _2. The second differential amplifier 12 constituted by the transistors T ₄ and T ₅ is driven by a constant current source formed by the transistor T ₆ configured between the emitters of both transistors and the ground GND to balance and amplify the high frequency signal. That is, the second differential amplifier 12 is amplified by the first differential amplifier 11 and amplifies the high frequency signal applied to the bases of the transistors T ₄ and T ₅ .

The constant current source formed by the transistors T ₃ and T ₆ serves to vary the bias currents of the first and second differential amplifiers 11 and 12 in response to the gain control signal under the control of the bias current circuits 15 and 16. The amplification gains of the differential amplifiers 11 and 12 are variably set. By such variable control of the bias current, the amplification gain setting of the differential amplifiers 11 and 12 suitable for the level of the high frequency signal and the automatic gain adjustment (AGC) for the high frequency signal are performed.

Furthermore, the bias current circuits 15 and 16 can be configured to control the operation of the transistors T ₃ and T ₆ according to the ambient temperature, so that the bias current circuits 15 and 16 can have functions such as temperature compensation for the differential amplifiers 11 and 12. Do.

The push-pull circuit 13 consists mainly of a pair of transistors T ₇ , T ₈ , the emitters of both transistors are grounded together, and the base is connected to the collectors of transistors T ₄ , T ₅ , which form a second differential amplifier 12. Each is connected via a capacitor. That is, the push-pull circuit 13, and the high frequency signal amplified by the differential amplifier 12 to a balanced input amplifier, the transistor T _7, it is possible to obtain the equilibrium the amplified output between the collector of T _8.

Between the bases of the transistors T ₇ and T ₈ , a pair of driving transistors T ₉ and T ₁₀ that define the base currents of both transistors and further the bias currents of the push-pull circuit 13 are provided. Each of the driving transistors T ₉ and T ₁₀ is driven by the third bias current circuit 17 via the transistor T ₁₁ to operate a constant current. The driving transistors T ₉ and T ₁₀ vary the base currents of the transistors T ₇ and T ₈ under the control of the bias current circuit 17, thereby optimizing the DC bias current of the push-pull circuit 13.

If the output stage of the high frequency power module (RF power amplifier) 206 is configured in the form of a push-pull amplifier circuit as described above, the constant current circuit between the emitter and the ground required in the differential amplifier circuit format becomes unnecessary, and the use efficiency of the power supply voltage This is the maximum. On the other hand, in the output stage of the push-pull amplifier circuit type, by providing a bias current variable control circuit between the base and ground, it is necessary to make a circuit structure having a high impedance with respect to a high frequency signal.

Therefore, in the embodiment of the present invention, the driving transistor T _9, against the base of the _{T 10 R 3, R 4:} R 3, by connecting R ₅ each is reduced upset high impedance of the drive transistor, the transistor for the high frequency signal T _7, and is maintained stably operating condition of T _8, the transistor T _7, to optimize the bias current of the push-pull circuit 13, which performs the T ₈ so as to prevent an increase in power loss.

According to the high-frequency power module (RF power amplifier) 206 according to the present invention in which the input stage is constituted by the cutoff amplifiers 11 and 12 and the output stage is configured as the push-pull circuit 13 as described above, the power module 206 With respect to the high frequency grounding pattern of the circuit board mounted with the RF power amplifier, the RF power amplifier balances and amplifies and balances the high frequency signal at the lower part of the virtual ground. That is, the RF power amplifier 206 operates in a floating state with respect to the high frequency ground pattern.

Therefore, the high frequency power module mounted on the printed circuit board can be stably operated without being affected by the high frequency ground pattern. Furthermore, in the high frequency power module 206, since the bias current of the differential amplifiers 11 and 12 is varied in accordance with the gain control signal, the amplification gains of the differential amplifiers 11 and 12 are varied so that gain control is easy and gain gain is amplified. It can be stably varied.

To lower the transmit power, the bias currents of the differential amplifiers 11, 12 and the push-pull circuit 13 of the module 206 are reduced to reduce the amplification gain of the amplifier elements 11, 12, 13. When transmitting low transmission power, the bias current of such amplifier elements 11, 12, 13 is reduced and the transmit current is maximized because the bias current of the push-pull circuit 13 is optimized in correspondence with the transmission output level. Significantly reduced from, keeps the power amplifier linear, while avoiding unwanted power losses.

In particular, according to the preferred embodiment of the present invention, it is possible to prevent a significant decrease in power efficiency in the push-pull circuit 13. Therefore, the power amplifier according to the present invention can prevent unnecessary power consumption when the transmission output varies widely from low transmission output level to high output level.

4 shows the relationship between the transmission power and the power efficiency in the high frequency power module 206 according to the present invention and the RF power amplifier according to the prior art as solid lines A and broken lines B, respectively. Referring to Fig. 4, the power efficiency of the power module 206 when the transmission power is reduced by about 1 kHz is about 10%, while the power efficiency of the RF power amplifier according to the prior art is about 1%. That is, it can be seen that the power efficiency of the power module 206 according to the present invention in the low transmission power level region is considerably higher than in the prior art.

Fig. 5 shows the relationship between the transmission output level range and the frequency of use in a CDMA mobile telephone having a maximum transmission power of 1 W. Figs. Referring to Fig. 5, it can be seen that in practice, the mobile phone is rarely driven at the maximum output power, but in most cases, the mobile phone is driven at the low output power of 10 mu s or less. In view of such a trend, it is important to increase the signal quality and the power efficiency at the time of low output of 10 kHz or less.

The high frequency power module 206 can adjust the transmission output only by adjusting the bias currents for the differential amplifiers 11 and 12 and the push-pull circuit 13, and in particular, can improve power efficiency in the low output level region, thereby saving power. The effect is very big. The technical idea according to the present invention is not limited to the above embodiment, and various modified embodiments are possible.

For example, depending on the amplification gain required to obtain a desired level of transmission signal, it is possible to implement the input stage of the RF power amplifier (RF power module) as one differential amplifier or to configure three or more stages of differential amplifiers directly. Do. In addition, an output transistor of the output terminal of the RF power amplifier may be connected to a Darlington circuit. In addition, although the RF power amplifier is configured using the npn transistor as the embodiment of the present invention described above, a pnp transistor may be used.

When the high frequency power module according to the present invention is implemented using a monolithic integrated circuit, as well as using a silicon bipolar transistor, a heterojunction bipolar transistor (HBT) using a group III-V compound semiconductor such as gallium arsenide (GaAs), PHEMT (pseudomorphic high electron mobility transister), MESFET, or insulated gate type bipolar transistor (IGBT) may be used.

Moreover, although embodiments of the present invention have integrated the RF power amplifier, it is not necessary to do so. Since the RF power amplifier 206 of the present invention has an automatic gain control function as described above, the automatic gain control circuit 203 can be omitted from the transmitter 2t.

In addition, although a case of being mounted on a W-CDMA mobile phone as a preferred embodiment of the present invention has been described above, the RF power amplifier according to the present invention can be mounted on various kinds of mobile devices, and in particular, a portable type is required to reduce power consumption. Suitable for mobile devices The circuit configuration of each part of the mobile device corresponds to the specifications of the mobile device.

In the RF power amplifier according to the embodiment of the present invention, although both the input terminals 11 and 12 and the output terminal 13 are configured as balanced circuits, either the input terminal or the output terminal is configured as a balanced circuit and the other is unbalanced. It can also be configured as a circuit.

6 shows an RF power amplifier 401 having an input stage 401 constituting an unbalanced circuit comprising an amplifier and a balun and an output stage 402 constituting a balanced circuit.

7 shows an RF power amplifier having an input stage 501 constituting a balanced circuit and an output stage 502 constituting an unbalanced circuit including an amplifier and a balun. RF GND denotes an RF ground pattern. 6 and 7, the bias current circuit is not shown.

The foregoing has outlined rather broadly the features and technical advantages of the present invention to better understand the claims of the invention which will be described later. Additional features and advantages that make up the claims of the present invention have been described above. It should be appreciated by those skilled in the art that the conception and specific embodiments of the invention disclosed may be readily used as a basis for designing or modifying other structures for carrying out similar purposes to the invention.

In addition, the inventive concepts and embodiments disclosed herein may be used by those skilled in the art as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. In addition, such modifications or altered equivalent structures by those skilled in the art may be variously changed, substituted, and changed without departing from the spirit or scope of the invention described in the claims.

The RF power amplifier according to the present invention can amplify a high frequency signal while maintaining the linearity of the amplifier without being affected by the high frequency ground pattern. In addition, the transmission output level can be changed easily and stably, and in particular, the power efficiency of the RF power amplifier in the low output level region can be improved.

As a preferred embodiment of the RF power amplifier according to the present invention, in the case of configuring a high frequency module mounted on a circuit board together with a modulator, a frequency converter and a receiving system of a mobile device to perform a function as a high frequency part of a mobile device, modularization Since the high frequency part can reduce the size or reduce the power consumption, a mobile device that requires a large number of circuit components, and at the same time requires linearity of transmission power, as in a mobile device of a wide-band division multiple access (W-CDMA) system. Solve the problems that occur in configuring.

In addition, the RF power amplifier according to the present invention improves its versatility by modularizing the high frequency part and can be applied to mobile devices of various specifications.

The integrated circuit RF power amplifier according to the present invention makes it possible to manufacture a power amplifier such that its operational stability is compensated, thereby mitigating the mounting conditions of the power amplifier on the circuit board. Accordingly, the power amplifier integrated in accordance with the present invention can be combined with each other in that the mounting conditions are alleviated with the advantage of being compact, thereby facilitating high frequency modularization.

The RF power amplifier according to the present invention has a high power efficiency, and as a result is particularly suitable for providing a portable mobile device such as a cellular phone using a battery as a power source.

Claims (19)

An input stage comprising at least one differential amplifier which balances and amplifies a high frequency signal output from a frequency converter disposed at a rear end of a modulation unit of a transmission system of a mobile device; And A bias current circuit for supplying a bias current that changes in response to a gain control signal to the at least one differential amplifier and variably setting the gain of the differential amplifier And an RF power amplifier mounted on a circuit board of the mobile device, wherein a high frequency ground pattern is formed on the circuit board. The RF power amplifier of claim 1, wherein an input terminal of the RF power amplifier is composed of a plurality of differential amplifiers directly connected to each other, and the bias current circuit is supplied to each of the plurality of differential amplifiers. The RF power amplifier of claim 1, wherein the gain control signal is a signal transmitted from a wireless base station or a control unit of the mobile device to determine a power output level of the mobile device. The RF power amplifier of claim 1, wherein the RF power amplifier is mounted on the circuit board together with the modulator, the frequency converter, and the receiving system of the mobile device to form an RF module that functions as a high frequency part of the mobile device. RF power amplifier. 5. The RF power amplifier of claim 4, wherein the RF power amplifier is implemented in the form of an integrated circuit. 5. The RF power amplifier as claimed in claim 4, wherein the RF power amplifier is mounted in a portable mobile device. In the RF power amplification device for mobile devices, An output stage comprising a push-pull circuit for amplifying and outputting a high frequency signal inputted from an frequency converter arranged at a rear end of a modulation section of a transmission system of a mobile device through an input terminal of the RF power amplifier; And A bias current circuit that varies the bias current of the push-pull circuit according to a gain control signal And the RF power amplifier is mounted on a circuit board of the mobile device, wherein the RF board is formed with a high frequency ground pattern. 8. The bias current circuit of claim 7, wherein the bias current circuit varies an operating current of a constant current circuit connected to each base of a pair of transistors forming the push pull circuit, thereby varying a bias current of the push pull circuit. RF power amplifier, characterized in that. 8. The RF power amplifier according to claim 7, wherein the gain control signal is a signal transmitted from a wireless base station or a control unit of the mobile device to determine a transmission output level of the mobile device. 8. The RF power amplifier of claim 7, wherein the RF power amplifier includes an RF module mounted on the circuit board together with the modulator, the frequency converter, and the receiving system of the mobile device, and functions as an RF part of the mobile device. Power amplifier. 11. The RF power amplifier of claim 10, wherein the RF power amplifier is configured in the form of an integrated circuit. 11. The RF power amplifier of claim 10, wherein the RF power amplifier is mounted in a portable mobile device. In the RF power amplifier for mobile devices, An input stage comprising at least one differential amplifier which balances and amplifies a high frequency signal output from a frequency converter disposed at a rear end of a modulation unit of a transmission system of a mobile device; A first bias current circuit for supplying the at least one differential amplifier with a bias current that changes in response to a gain control signal to variably set the gain of the corresponding differential amplifier; An output stage configured to amplify the high frequency signal outputted from the input stage, amplified by the input stage, and to form a push-pull circuit; And And a second bias current circuit configured to vary the bias current of the push-pull circuit in response to a gain control signal, wherein the RF power amplifier is mounted on a circuit board of the mobile device, and the circuit board is formed with a high frequency ground pattern. RF power amplifier. The RF power amplifier according to claim 13, wherein an input terminal of the RF power amplifier is composed of a plurality of differential amplifiers to be directly spaced apart from each other, and the bias current circuit is configured in each of the differential amplifiers. The method of claim 13, wherein the second bias current circuit varies the operating current of the constant current circuit connected to each base of the pair of transistors forming the push pull circuit, thereby varying the bias current of the push pull circuit. RF power amplifier, characterized in that. The RF power amplifier according to claim 13, wherein the gain control signal is a signal transmitted by a wireless base station or a control unit of the mobile device to determine a transmission output level of the mobile device. The RF power amplifier according to claim 13, wherein the RF power amplifier is mounted on the circuit board together with the modulator, the frequency converter, and the receiving system of the mobile device, to form an RF module that functions as a high frequency part of the mobile device. Power amplifier. 18. The RF power amplifier of claim 17, wherein the RF power amplifier is integrated circuit. 18. The RF power amplifier of claim 17, wherein the RF power amplifier is mounted in a portable mobile device.