KR100326311B1 - Apparatus for controlling a power level of transmission signal and method in a mobile telecommunication terminal - Google Patents

Abstract

Disclosed are a transmission power control apparatus and method for a mobile communication terminal that selects a suitable power amplifier according to a transmission power level. In the present invention, a mobile communication terminal having two power amplifiers connected in parallel selects and uses a low power level power amplifier and selects or uses a high power level power amplifier. If it is necessary to select a power amplifier with a low power level, the variable attenuator is controlled and adjusted so that the difference in power gain between the two power amplifiers is within a preset range, and then one of the two power amplifiers is selected. We propose a transmission power control device. At this time, the selection criteria of the power amplifier is determined by the controller determining the output signal level determined by the received signal strength (RSSI) detector and determining the output power level according to the determination result. The controller selects a power amplifier having a high power level when the detected received signal has a small intensity, and selects a power amplifier having a low power level when the detected received signal has a high intensity. The selection operation of the power amplifier is performed by switching control of the switching units provided in the high frequency signal input terminal and the high frequency signal output terminal. In addition, the present invention uses a method of controlling the bias voltage and the bias current of the power amplifier in order to minimize the power consumption of the power amplifier at all power levels to change the efficiency.

Description

Transmission power control apparatus and method of mobile communication terminal {APPARATUS FOR CONTROLLING A POWER LEVEL OF TRANSMISSION SIGNAL AND METHOD IN A MOBILE TELECOMMUNICATION TERMINAL}

The present invention relates to a transmission power control apparatus and method of a mobile communication terminal, and more particularly to a transmission power control apparatus and method for transmitting a high frequency signal by selecting a power amplifier suitable for the power level for the transmission.

In general, a high frequency signal is applied to a terminal of a mobile communication system (hereinafter referred to as a 'mobile communication terminal') such as a code division multiple access (CDMA) method or a personal communication services (PCS) method. Through the transmission, the signal from the base station is received through the antenna. For this transmission and reception operation, a power amplifier is provided at a transmission end of the mobile communication terminal.

The power amplifier occupies a large portion of the characteristics and power consumption of the system. The power amplifier is not always driven at the maximum output power, but varies the output power level according to the distance from the base station and the user's moving speed. When the distance between the base station and the mobile communication terminal is close, that is, when the strength of the received signal is large, the output power level of the power amplifier is relatively decreased. On the contrary, when the mobile communication terminal moves to the furthest place within the cell radius, that is, when the received signal strength is small or the user's moving speed is increased, the power amplifier has a high frequency signal close to the maximum output power level. Will be sent. These power amplifiers are designed to have the highest efficiency at maximum output power. Therefore, there is a problem that the efficiency of the power amplifier is sharply lowered at a low level of the output power.

Techniques for solving this problem are shown in FIG. 1 is identical to the configuration shown in FIG. 4 under Korean Patent Application No. 97-69207, entitled “Power Saving Device for Wireless Communication Terminal,” filed December 16, 1997 by the same applicant as the applicant of the present application. Configuration.

Referring to FIG. 1, a power amplifier PA1 104 for use in a large transmission power and a power amplifier PA2 108 for use in a small transmission power are connected in parallel, and are separated through the switching units 102 and 110. have. The controller 114 determines a power output level according to the received signal strength detected by the received signal strength indicator (RSSI) detector 112, and selects a power amplifier suitable for the level determined by switching control of the switching units 102 and 110. That is, the controller 114 controls the switching units 102 and 104 to select a power amplifier 104 capable of outputting a high power signal when the level of the output signal corresponding to the strength of the received signal is higher than or equal to a preset level. At this time, the control unit 114 also controls the power supply unit 106 so that the operating power Va1 suitable for the operation of the power amplifier 104 is supplied, and the operating power Va2 is 0 volts. On the other hand, when the level of the output signal corresponding to the strength of the received signal is less than the predetermined level, the control unit 114 controls the switching unit 102, 104 to select the power amplifier 108 that enables the output of a low power signal. At this time, the control unit 114 also controls the power supply unit 106 so that the operating power supply Va2 suitable for performing the operation of the power amplifier 108 is supplied, and the operating power supply Va1 is 0 volt.

As described above, the transmission power control apparatus as shown in FIG. 1 may perform only the operation of the power amplifier 108 having a small power consumption when the small transmission power is required, and block the operation of the power amplifier 104 having the large power consumption. This prevents unnecessary power consumption and improves the efficiency of the power amplifier.

However, the transmission power control device as shown in FIG. 1 has the following problems.

In FIG. 1, since the difference in power gain between the high power level amplifier 104 and the low power level amplifier 108 is large, switching from a low power level amplifier to a high power level amplifier or a high power level amplifier When switching to a power amplifier of low power level in the output power instantaneous increase or decrease occurs. In particular, when the output power level is momentarily increased by switching from a low power level power amplifier to a high power level power amplifier, noise and interference components in a given cell may increase momentarily to interfere with communication of other terminal users. Will occur.

In addition, when switching the two power amplifiers connected in parallel there is a problem that must be connected to a new matching circuit for impedance matching. In addition, when the transmission power control apparatus of FIG. 1 needs to support two or more transmission power levels, it may be difficult to implement due to the complexity of the circuit, and the efficiency may be increased within a certain range, but may be optimized. There is no problem.

Accordingly, an object of the present invention is to provide an apparatus and method for removing a phenomenon in which the output power is instantaneously increased or decreased according to the switching of the power amplifier in a mobile communication terminal having two power amplifiers connected in parallel.

Another object of the present invention is to provide an apparatus and method for preventing communication of another terminal user from being interrupted by switching of the power amplifier in a mobile communication terminal having two power amplifiers connected in parallel.

It is still another object of the present invention to provide an apparatus and method that do not require connection of a new matching circuit as a power amplifier is switched in a mobile communication terminal having two power amplifiers connected in parallel.

It is still another object of the present invention to provide an apparatus and method for simplifying circuit implementation even if a mobile communication terminal having two power amplifiers connected in parallel supports two or more output power levels.

In order to achieve the above object, the present invention is to select and use a low power level power amplifier in a mobile communication terminal having two power amplifiers connected in parallel, and to select a high power level power amplifier or a high power level power amplifier. If it is necessary to select and use a low power level power amplifier after selecting and using an amplifier, the variable attenuator is controlled and adjusted so that the difference in power gain between the two power amplifiers is within a preset range, and then any one of the two power amplifiers is used. We propose a transmission power control device that selects a suitable power amplifier. At this time, the selection criteria of the power amplifier is determined by the controller determining the output signal level determined by the received signal strength (RSSI) detector and determining the output power level according to the determination result. The controller selects a power amplifier having a high power level when the detected received signal has a small intensity, and selects a power amplifier having a low power level when the detected received signal has a high intensity. The selection operation of the power amplifier is performed by switching control of the switching units provided in the high frequency signal input terminal and the high frequency signal output terminal. In addition, the present invention uses a method of controlling the bias voltage and the bias current of the power amplifier in order to minimize the power consumption of the power amplifier at all power levels to change the efficiency.

1 is a view showing the configuration of a transmission power control apparatus according to the prior art including two power amplifiers connected in parallel.

2 is a configuration diagram according to a method of continuously controlling the bias to obtain the maximum efficiency according to the output level used in the present invention.

3 is a view showing the configuration of a transmission power control apparatus of a mobile communication terminal according to a first embodiment of the present invention.

4 is a view showing the configuration of a transmission power control apparatus of a mobile communication terminal according to a second embodiment of the present invention.

5 is a view showing the configuration of a transmission power control device of a mobile communication terminal according to a third embodiment of the present invention.

6 is a flowchart illustrating the processing of the transmission power control operation of the mobile communication terminal according to the present invention;

7 is a view showing that the bias operating point is changed during the bias control operation according to the output power level.

8a and 8b is a view showing a variation of the transmission power by the transmission power control apparatus according to the prior art and the present invention.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First of all, the present invention selects and uses a low power level power amplifier in a mobile communication terminal having two power amplifiers connected in parallel, and selects or uses a high power level power amplifier. Then, if it is necessary to select a power amplifier with a low power level, the variable attenuator is controlled and adjusted so that the difference in power gain between the two power amplifiers is within a predetermined range, and then one of the two power amplifiers is selected. It is to be noted that the present invention relates to a transmission power control device selected. At this time, the selection criteria of the power amplifier is determined by the controller determining the output signal level determined by the received signal strength (RSSI) detector and determining the output power level according to the determination result. That is, the controller selects a power amplifier having a high power level when the detected received signal has a small intensity, and selects a power amplifier having a low power level when the detected received signal has a high intensity. The selection operation of the power amplifier is performed by switching control of the switching units provided at the high frequency signal input terminal and the high frequency signal output terminal. The transmission power control apparatus according to the present invention may be configured as shown in Figs.

In addition, the present invention adopts a scheme as shown in FIG. 2 to control the bias voltage and the bias current of the power amplifier in order to minimize the power consumption of the power amplifier at all power levels to be maximized efficiency. Such a scheme is shown in FIG. 3 under Korean Patent Application No. 98-23776, entitled “Output Power Control Device and Method for Mobile Communication Terminal,” filed June 23, 1998 by the same applicant as the applicant of the present application. A part of the figure is shown.

The output power control apparatus shown in FIG. 2 is a power amplifier 204,206 designed to maximize efficiency at the maximum output power so that the maximum efficiency can be obtained even when the output level of the output power is changed. This is because the bias is continuously controlled. To this end, the control unit 204 includes a memory that stores a bias voltage control value and a bias current control value corresponding to each of a series of received signal strengths. When the strength of the received signal is detected by the RSSI detector 208, the controller 210 determines an output power level according to the detected strength of the received signal, and adjusts a bias voltage control value Vbias_cnt1 and a bias current control value Vbias_cnt2 suitable for the determined output level. Supply to the bias current control value input terminals of the variable power supply 202 and the power amplifiers 204 and 206, respectively. This configuration aims at maximizing efficiency by maintaining the linearity of the bias voltage and current of the power amplifier even at low output power levels.

3 is a diagram showing the configuration of a transmission power control apparatus of a mobile communication terminal according to a first embodiment of the present invention. This embodiment has only one power amplifier for the simple implementation of the amplifier circuit instead of having two power amplifiers connected in parallel, and the power amplifier can power the input high frequency signal if a high power level is required. When the low power level is required, the input high frequency signal is transmitted directly to the antenna without passing through the power amplifier.

Referring to FIG. 3, the transmission power control apparatus of the mobile communication terminal includes only one power amplifier PA 330 for outputting a high frequency signal of a predetermined power level or higher, and includes a high frequency signal input terminal RFin and a high frequency signal output terminal. (RFout) is provided. The power amplifier 330 is designed to have a predetermined power gain (eg, 25 dBm).

The first port of the first switching unit 310 is connected to the high frequency signal input terminal RFin. The first switching unit 310 may include a first port connected to the high frequency signal input terminal RFin, a second port connected to the input terminal of the variable attenuator 320, and a third port connected to the third port of the second switching unit 340. Equipped. The second switching unit 340 includes a first port connected to the high frequency signal output terminal RFout, a second port connected to the output terminal of the power amplifier 330, and a third port connected to the third port of the first switching unit 310. Equipped. The first switching unit 310 and the second switching unit 340 are switched and controlled according to the selection control signal CNT1 from the controller 370. The first switching unit 310 and the second switching unit 340 may be directly connected to each other so that the input high frequency signal is directly output to the RF signal output terminal RFout without power amplification by the switching control by the controller 370. The unit 310 may be connected to the variable attenuator 320 and the second switching unit 340 may be connected to the power amplifier 330 such that the input high frequency signal is amplified by the variable attenuator 320 and the power amplifier 330 and then output to the high frequency signal output terminal RFout. . The first switching unit 310 and the second switching unit 340 may be implemented as a switch, it may be implemented as a circulator (circulator). The first switching unit 310 may be implemented as a coupler, or may be implemented as a divider. The second switching unit 340 may be implemented as a combiner.

A variable attenuator 320 is located in front of the power amplifier 330. The variable attenuator 320 is controlled by the variable attenuation control signal CNT2 from the controller 370 to adjust the power gain of the power amplifier 330 to be within a preset range. This adjustment operation is performed by the controller 370 determining the output power level according to the strength of the received signal detected by the received signal strength (RSSI) detector 360 (the switching amplifier 310 and the switching unit 320 are not selected). If a selection is required in the bypass path (by directly connected through the BYPASS) or if it is determined that the non-selection is necessary while the power amplifier 330 is being selected. The setting range is preferably 0 [dBm], but may be less than +/- number [dBm] since an error may occur substantially.

The power supply unit 350 supplies the operating power Va to the power amplifier 330 in response to the selection control signal CNT1 from the control unit 370. The operating power Va is supplied when the power amplifier 330 is selected, and is cut off when the power amplifier 330 is not selected, that is, when the switching unit 310 and the switching unit 320 are directly connected through the bypass path. In addition, the power supply unit 350 maintains the linearity of the bias voltage and the current of the power amplifier 330 even when the output power level is changed in response to the bias control signal CNT3 from the controller 370. The bias control signal CNT3 is a signal including a bias control voltage value and a bias control current value.

The operation performed by the transmission power control device as shown in FIG. 3 is as follows.

At the minimum output power level and the low output power level, the control unit 370 controls the switching units 310 and 340 according to the selection control signal CNT1 to bypass the power amplifier 330 and cut off the operating power Va of the power amplifier 330, thereby reducing the frequency of the high frequency signal input terminal RFin. Communication is made only through the output of the driving amplifier provided at the front end.

When the required output power level is increased, such as when the strength of the received signal is minute, and the driving of the power amplifier 330 is required, the controller 370 controls the variable attenuation control signal CNT2 so that the variable attenuator 320 positioned at the front end of the power amplifier 330 can be used. Once adjusted, the power gain of the power amplifier 330 is adjusted to a value within the preset range (preferably 0 [dBm]). The adjustment operation of the variable attenuator 320 is to prevent the level of the transmission power from being rapidly increased by the power gain as the power amplifier 330 is not used. In this state, the controller 370 controls the selection control signal CNT1 so that the switching unit 310 is connected to the variable attenuator 320, the switching unit 340 is connected to the power amplifier 330, and the operating power Va is supplied to the power amplifier 330 by the power supply unit 350. . As described above, after the switching units 310 and 340 are switched, the attenuation by the variable attenuator 320 is continuously reduced to increase the output power level. While the operating power Va is supplied to the power amplifier 330 by the power supply 350, the controller 370 reads the bias control signal CNT3 corresponding to the detected intensity of the received signal from the internal memory and supplies it to the power supply 350.

When the output power level is lowered, that is, when the power amplifier 330 is selected and used, but the power amplifier 330 is not selected, the same operation as described above is performed. That is, when it is necessary to lower the output power level, the controller 370 first controls the variable attenuator 320 to adjust the power gain of the power amplifier 330 to a value within a preset range, and then controls the switching units 310 and 340 to detour the path. To be selected.

When the above switching control operation is performed, a communication failure may occur due to frequent switching near the switched power level. Therefore, the power level and the output power level corresponding to the case of switching to the power amplifier 330 need to be increased due to an increase in the output power level. Hysteresis is made so that the corresponding power level is different when it is not necessary to select the power amplifier 330.

4 is a view showing the configuration of a transmission power control apparatus of a mobile communication terminal according to a second embodiment of the present invention. This embodiment includes two power amplifiers connected in parallel, and when a high power level is required, an input high frequency signal is amplified by a first power amplifier for outputting a high frequency signal above a predetermined power level, and then, When a low power level is required, the input high frequency signal is amplified by a second power amplifier for outputting a high frequency signal having a power level smaller than the set power level and then transmitted to the antenna.

Referring to FIG. 4, the transmission power control apparatus of the mobile communication terminal outputs a first power amplifier PA1 330 for outputting a high frequency signal having a predetermined power level or higher, and a high frequency signal having a power level smaller than the set power level. A second power amplifier (PA2) 380 is provided, and a high frequency signal input terminal RFin and a high frequency signal output terminal RFout are provided. The first power amplifier 330 is designed to have a predetermined power gain (eg, 25 dBm), and the second power amplifier 380 is designed to have a power gain (eg, 10 dBm) less than the set power gain. In other words, the power gain of the first power amplifier 330 is greater than that of the second power amplifier.

The first port of the first switching unit 310 is connected to the high frequency signal input terminal RFin. The first switching unit 310 includes a first port connected to the high frequency signal input terminal RFin, a second port connected to the input terminal of the variable attenuator 320, and a third port connected to the input terminal of the second power amplifier 380. have. The second switching unit 340 includes a first port connected to the high frequency signal output terminal RFout, a second port connected to an output terminal of the first power amplifier 330, and a third port connected to an output terminal of the second power amplifier 380. Equipped. That is, the first switching unit 310 is connected between the high frequency signal input terminal RFin and the variable attenuator 320 and between the second power amplifier, and the second switching unit 320 is connected to the first power amplifier 330 and the high frequency signal output terminal RFout. ) And between the second power amplifier 380 and the high frequency signal output terminal RFout. The first switching unit 310 and the second switching unit 340 are switched and controlled according to the selection control signal CNT1 from the controller 370. The first power amplifier 330 may be connected between the high frequency signal input terminal RFin and the high frequency signal output terminal RFout by the switching control by the controller 370, that is, between the first switching unit 310 and the second switching unit 340. In addition, the second power amplifier 380 may be connected. The first switching unit 310 and the second switching unit 340 may be implemented as a switch, it may be implemented as a circulator (circulator). The first switching unit 310 may be implemented as a coupler, or may be implemented as a divider. The second switching unit 340 may be implemented as a combiner.

A variable attenuator 320 is located in front of the first power amplifier 330. The variable attenuator 320 is controlled by the variable attenuation control signal CNT2 from the controller 370 to adjust the power gain of the power amplifier 330 to be within a preset range. This adjustment operation is performed when the controller 370 determines the output power level according to the strength of the received signal detected by the received signal strength (RSSI) detector 360 (the second power amplifier 380 is not selected). It is performed when it is determined that the selection is required in the selected and used state) or that the non-selection (selection of the second power amplifier 380) is required in the state where the first power amplifier 330 is selected and in use. The setting range is preferably 0 [dBm], but may be less than +/- number [dBm] since an error may occur substantially.

The power supply 350 supplies the operating power Va1 to the first power amplifier 330 or the operating power Va2 to the second power amplifier 380 in response to the selection control signal CNT1 from the controller 370. The operating power Va1 is supplied when the first power amplifier 330 is selected and shut down when the second power amplifier 380 is selected, and the operating power Va2 is supplied when the second power amplifier 380 is selected and the first power amplifier 330 is If selected, it is blocked. In addition, the power supply unit 350 maintains the linearity of the bias voltage and current of the power amplifiers 330 and 380 even when the output power level is changed in response to the bias control signal CNT3 from the controller 370. The bias control signal CNT3 is a signal including a bias control voltage value and a bias control current value.

The operation performed by the transmission power control device as shown in FIG. 4 is as follows.

At a low output power level, the control unit 370 controls the switching units 310 and 340 according to the selection control signal CNT1 to select the second power amplifier 380 and supply only the operating power Va2 of the second power amplifier 380, thereby inputting through the high frequency signal input terminal RFin. After the high frequency signal is amplified by the second power amplifier 380, the high frequency signal is output through the antenna via the switching unit 340 and the high frequency signal output terminal RFout.

When the required output power level is increased, such as when the strength of the received signal is minute, and the driving of the first power amplifier 330 is required, the controller 370 controls the variable attenuation control signal CNT2 so that the power gain is relatively large. The variable attenuator 320 located at the front end of the 330 is adjusted so that the difference in power gain between the first power amplifier 330 and the second power amplifier 380 is within a preset range (preferably 0 [dBm]). The adjustment operation of the variable attenuator 320 is to prevent a sudden increase in the level of the output power by the difference in the power gain as the first power amplifier 330 is not used. In this state, the controller 370 controls the selection control signal CNT1 so that the switching unit 310 is connected to the variable attenuator 320, the switching unit 340 is connected to the first power amplifier 330, and the operating power source Va1 is connected to the first power amplifier 330 by the power supply unit 350. To be supplied. As described above, after the switching units 310 and 340 are switched, the attenuation by the variable attenuator 320 is continuously reduced to increase the output power level. While the operating power supply Va1 is supplied to the first power amplifier 330 by the power supply unit 350, the control unit 370 reads the bias control signal CNT3 corresponding to the detected intensity of the received signal from the internal memory and supplies it to the power supply unit 350.

The same operation as described above is performed when the output power level is decreased, that is, when it is necessary to select and use the first power amplifier 330 and then select the second power amplifier 380. That is, when it is necessary to lower the power output level, the controller 370 first controls the variable attenuator 320 to adjust the difference in power gain between the first power amplifier 330 and the second power amplifier 380 to be within a preset range. The second power amplifier 380 is selected by controlling the switching units 310 and 340.

When the above switching control operation is performed, communication failure may occur due to frequent switching near the switched power level. Therefore, the power level and the output power corresponding to the case where switching to the first power amplifier 330 are required due to an increase in the output power level are required. The hysteresis is set so that the power level corresponding to the switching to the second power amplifier 380 is different.

5 is a view showing the configuration of a transmission power control apparatus of a mobile communication terminal according to a third embodiment of the present invention. This embodiment is a further improvement of the above-described first and second embodiments. That is, the transmission power control apparatus according to the first and second embodiments solves the problem caused by the difference in power gain between the power amplifiers by controlling the variable attenuator 320, and instead of using a fixed voltage / current bias. The bias voltage / current is adaptively controlled according to the power level, but in practical applications, the complexity of the control scheme and the control circuit can reduce the efficiency of the entire system. Accordingly, the transmission power control apparatus according to the third embodiment equals the gains of the two power amplifiers connected in parallel, and maintains the required linearity as the current of each power amplifier changes the operating power level of the power amplifier. The efficiency is automatically improved without control by the controller. That is, the power gain is the same, and the bias voltage and the bias current control operation according to the output level of the power amplifier are automatically controlled internally.

Referring to FIG. 5, the power transmission control apparatus according to the third embodiment connects the power amplifiers 390A and 390B optimized in efficiency at two levels with high and low power output levels in parallel, and at the corresponding level. Allow the corresponding power amplifier to switch. The power amplifiers 390A and 390B are adaptive bias control power amplifiers (ABPAs) designed to have an optimized efficiency by automatically adjusting the bias current and the voltage according to the output power level. In this case, the power gains of the power amplifiers 390A and 390B are the same, thereby reducing the use of the variable attenuator as shown in FIGS. 3 and 4.

According to the recent semiconductor device technology and amplifier design technology, it is possible to manufacture a power amplifier that has the same power gain even when the output power level is low and the efficiency is not reduced even at the minimum output power level. It can also be used. Therefore, it is possible to effectively improve the efficiency of the power amplifier of the mobile communication terminal by simply switching the power amplifier and power supply control according to the output power level. At this time, hysteresis is performed between the output power level to be switched when the output power level is increased to avoid communication failure due to frequent switching near the power level being switched, and the output power level to be switched when the power supply level is reduced. hysteresis).

6 is a flowchart illustrating the processing of the transmission power control operation of the mobile communication terminal according to the present invention. The operation according to the processing flow is performed in all the power transmission control apparatus shown in Figs. 3 to 5, but for the convenience of description, it will be described here as limited to the operation performed in the power transmission control apparatus shown in Fig. do.

The RSSI detector 360 of FIG. 4 detects the strength of the signal received from the base station in step 601 of FIG. 6, and notifies the controller 370 of the detection result. In step 602, the controller 370 determines the output power level from the detected strength of the received signal, and determines which power amplifier to select from among the power amplifiers 330 and 380. In this case, when it is necessary to send a signal of a high power level, it is determined that the first power amplifier 330 is selected, and when it is necessary to send a signal of a low power level, it is determined that the second power amplifier 380 is selected.

After determining which power amplifier to select, the control unit 370 controls the variable attenuator 320 in step 603 to control the difference between the power gains of the power amplifiers 330 and 380, before switching the switching units 310 and 340 so that the determined power amplifier is selected immediately. Adjust so that is within the preset range. After adjusting the power gain difference between the power amplifiers 330 and 380 to be within a preset range, the controller 370 controls the switching units 310 and 340 to select the determined power amplifier in step 604, and controls the power supply unit 350 in step 605. Ensure that the operating power is supplied to the selected power amplifier.

As such, a power amplifier supporting an output level suitable for the current received signal strength is selected, and the selected power amplifier amplifies the input high frequency signal to an appropriate output level in step 606. The power-amplified high frequency signal is output through the antenna via the second switching unit 340 and the high frequency signal output terminal RFout in step 607. The high frequency signal of the mobile communication terminal is transmitted to the base station.

7 is a view showing that the bias operating point is changed during the bias control operation according to the output power level. The change of the bias operating point is performed by the control unit 370 of the transmission power control apparatus according to the present invention supplying the bias control signal CNT3 to the power supply 350 to control the bias voltage and current of the power amplifier. In FIG. 7, the bias A is a bias operating point determined when a high frequency signal having a high power output level is transmitted, and the bias B is a bias operating point determined when a high frequency signal with a low power level is transmitted.

8a and 8b is a view showing a variation of the transmission power by the transmission power control apparatus according to the prior art and the present invention.

8A illustrates that when the variable power attenuator is not used, such as the power transmission control apparatus according to the related art shown in FIG. 1, the power output increases rapidly when switching the power amplifiers as the power output level is increased or decreased. Or to show a decrease. This phenomenon causes a problem that other users in the cell are interrupted during communication.

FIG. 8B illustrates that the power attenuation increases or decreases by adjusting the variable attenuator before switching the power amplifiers as the power supply level increases or decreases as in the power supply control device according to the present invention. Figure showing.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, in the present invention, the mobile communication terminal needs to transmit a low power level signal and then transmit a high power level signal, or transmit a high power level signal and then send a low power level signal. In this case, there is an advantage of eliminating the occurrence of a communication failure by eliminating the phenomenon in which the output power increases or decreases rapidly. In addition, the present invention is to maintain the linear characteristics even at a low output level and to control the efficiency to the maximum to save the power consumption of the battery during the call, there is an advantage that can extend the time to use the terminal without recharging the battery .

Claims (31)

In the transmission power control apparatus of a mobile communication terminal for transmitting a high frequency signal through an antenna, and receives a signal from a base station through the antenna, A first power amplifier for outputting a high frequency signal of a predetermined power level or more; A second power amplifier connected in parallel to the first power amplifier and outputting a high frequency signal having a power level smaller than the power level; A variable attenuator positioned at the front end of the first power amplifier; A received signal strength detector for detecting the strength of the received signal; The output power level is determined according to the detected intensity of the received signal, the variable attenuator is controlled to adjust the difference in power gain between the two power amplifiers to be within a preset range, and then the first power amplifier and the first power amplifier. A control unit for selecting one of the two power amplifiers; And a power supply unit configured to supply an operating power suitable for the selected power amplifier under the control of the controller so that an input high frequency signal is amplified by the selected power amplifier and then transmitted through the antenna. The method of claim 1, wherein the control operation of the variable attenuator by the control unit requires selection of the second power amplifier while the determined output power level is being selected by the first power amplifier, or the second power amplifier. Is performed when it is determined that the selection to the first power amplifier is necessary in the state of selecting. The apparatus of claim 1, wherein the controller controls the variable attenuator such that a difference in power gain between the two power amplifiers is '0'. The apparatus of claim 1, wherein the selection of the first power amplifier and the selection of the second power amplifier are performed at different output power levels. The apparatus of claim 4, wherein the received signal strength corresponding to the case where the selection of the first power amplifier is required is greater than the received signal strength corresponding to the case where the selection of the second power amplifier is required. The method of claim 1, wherein the controller is further configured to store bias voltage control values and bias current control values for determining biases of the first power amplifier and the second power amplifier corresponding to each of a series of received signal strengths. And a memory for providing a bias voltage control value and a bias current control value corresponding to the selected power amplifier. The method of claim 1, A first switching unit connected between an input terminal for inputting a high frequency signal and the variable attenuator and between the second power amplifier; And a second switching unit connected between the first power amplifier and an output terminal for outputting a high frequency signal and between the second power amplifier and the output terminal. Wherein the first switching unit and the second switching unit are controlled to be controlled by the control unit. The apparatus of claim 7, wherein the first switching unit and the second switching unit are implemented as a circulator. The apparatus of claim 7, wherein the first switching unit and the second switching unit are implemented as a switch. The apparatus of claim 7, wherein the first switching unit is a coupler. The apparatus of claim 7, wherein the first switching unit is a divider. The apparatus of claim 7, wherein the second switching unit is a combiner. In the transmission power control apparatus of a mobile communication terminal for transmitting a high frequency signal through an antenna, and receives a signal from a base station through the antenna, A power amplifier for outputting a high frequency signal of a predetermined power level or more; A variable attenuator positioned at the front end of the power amplifier; A received signal strength detector for detecting the strength of the received signal; The output power level is determined according to the detected intensity of the received signal, the variable attenuator is controlled to adjust the power gain of the power amplifier to a value within a preset range, and then the input high frequency signal is amplified by the power amplifier. A control unit to be transmitted through the antenna after being directly or And a power supply unit for supplying operating power to the power amplifier under the control of the controller. The method of claim 13, wherein the controlling operation of the attenuator by the control unit is determined that the determined output power level is required to be selected in a state in which the power amplifier is not selected, or to be deselected in a state in which the power amplifier is being selected. Transmission power control device, characterized in that performed in the case. The apparatus of claim 13, wherein the controller controls the variable attenuator so that the power gain of the power amplifier is 0 [dBm]. The memory device of claim 13, wherein the controller comprises a memory configured to store a bias voltage control value and a bias current control value for determining a bias of the power amplifier corresponding to each of a series of received signal strengths. Output power control apparatus characterized by providing a corresponding bias voltage control value and a bias current control value to the amplifier. The method of claim 13, A first port having a first port connected to an input terminal for inputting a high frequency signal, a second port connected to an input terminal of the variable attenuator, and a third port; A second switching unit including a first port connected to an output terminal for outputting a high frequency signal, a second port connected to an output terminal of the power amplifier, and a third port connected to a third port of the first switching unit; More, Wherein the first switching unit and the second switching unit are controlled to be controlled by the control unit. 18. The apparatus of claim 17, wherein the first switching unit and the second switching unit are implemented as circulators. 18. The apparatus of claim 17, wherein the first switching unit and the second switching unit are implemented by a switch. 18. The apparatus of claim 17, wherein the first switching unit is a coupler. 18. The apparatus of claim 17, wherein the first switching unit is a divider. 18. The apparatus of claim 17, wherein the second switching unit is a combiner. A first power amplifier for outputting a high frequency signal having a predetermined power level or more, a second power amplifier for outputting a high frequency signal having a power level smaller than the power level, and a high frequency signal input terminal and an input terminal of the power amplifiers. A first switching unit, a second switching unit connected between the output terminals of the power amplifiers and the high frequency signal output terminal, and a variable attenuator positioned in front of the first power amplifier, In the transmission power control method of a mobile communication terminal for transmitting an output high frequency signal from one of the power amplifier through an antenna, and receiving a signal from a base station through the antenna, (A) detecting the strength of the received signal; (B) determining an output power level according to the detected intensity of the received signal; (C) adjusting the variable attenuator so that the power gain difference between the two power amplifiers is within a preset range when it is determined that the selection of the power amplifier that is not selected corresponding to the determined output power level is necessary. and, The first switching unit and the second switching unit are controlled to select any one of the first power amplifier and the second power amplifier, and supply an operating power suitable for the selected power amplifier to select an input high frequency signal And transmitting the power through the antenna after being amplified by a power amplifier. 24. The method of claim 23, wherein the step (c) includes selecting the second power amplifier or selecting the second power amplifier while the detected received signal strength is being selected by the first power amplifier. Transmitting power control method, characterized in that performed when it is determined that the selection to the first power amplifier in the state is necessary. 24. The method of claim 23, wherein the variable attenuator is controlled such that a difference in power gain between the two power amplifiers is '0'. 24. The method of claim 23, wherein the selection of the first power amplifier and the selection of the second power amplifier are performed at different received signal strengths. 24. The method of claim 23, further comprising reducing the attenuation caused by the variable attenuator to increase the output level of the first power amplifier when the first power amplifier is selected while the second power amplifier is being selected. Transmission power control method. A power amplifier for outputting a high frequency signal of a predetermined power level or more; A variable attenuator positioned at the front end of the power amplifier; A first switching unit including a first port connected to an input terminal for inputting a high frequency signal, a second port connected to an input terminal of the variable attenuator, and a third port; A second switching unit including a first port connected to an output terminal for outputting a high frequency signal, a second port connected to an output terminal of the power amplifier, and a third port connected to a third port of the first switching unit; In the transmission power control method of the mobile communication terminal for transmitting a high frequency signal output through the second switching unit through an antenna, and receives a signal from the base station through the antenna, (A) detecting the strength of the received signal; (B) determining an output power level according to the detected intensity of the received signal; (C) controlling the variable attenuator so that the power gain of the power amplifier is within a preset range when it is determined that the selection of the currently unselected power amplifier is required to correspond to the determined output level; (D) controlling the first switching unit and the second switching unit so that an input high frequency signal is output by the power amplifier after being amplified or directly transmitted through the antenna. . 29. The method of claim 28, wherein the step (c) further comprises: when the detected intensity of the received signal is required to be selected in a state in which the power amplifier is not selected or in a state in which the power amplifier is being selected, non-selection is required. Transmission power control method, characterized in that performed in. 29. The method of claim 28, wherein the variable attenuator is controlled so that the power gain of the power amplifier is 0 [dBm]. 29. The method of claim 28, further comprising reducing the attenuation caused by the variable attenuator to increase the output level of the power amplifier when the power amplifier is selected in a non-selected state.