KR101125948B1 - Low noise amplifying apparatus having multi-step variable gain and method therefor - Google Patents

Abstract

The present invention relates to a low noise amplifier having a multi-stage variable gain suitable for a direct conversion receiver of a mobile communication terminal, and a method thereof. The present invention provides a low noise amplifier having a variable gain required in a direct conversion receiver. It is possible to reduce the manufacturing cost of the mobile communication terminal by using low-cost parts that are easily available without using integrated circuits. In particular, it is essential to improve the receiver and intermodulation distortion characteristics of the PCS band without intermodulation distortion test. The implementation is suitable for cellular band receivers.

Mobile communication terminal, receiver, direct conversion, variable gain, low noise amplifier, LNA

Description

LOW NOISE AMPLIFYING APPARATUS HAVING MULTI-STEP VARIABLE GAIN AND METHOD THEREFOR}

1 is a block diagram showing the configuration of a conventional super heterodyne receiver.

2 is a block diagram showing the configuration of a conventional direct conversion receiver.

Figure 3 is a structural diagram showing the structure of a low noise amplifying device having a multi-stage variable gain according to an embodiment of the present invention.

Figure 4 is a structural diagram showing in detail the structure of a low noise amplifying device having a multi-stage variable gain of Figure 3 in accordance with an embodiment of the present invention.

Figure 5 is a flow chart showing a multi-stage variable gain providing method of a low noise amplifier according to an embodiment of the present invention.

Figure 6 is a structural diagram showing the structure of a low noise amplifying device having a variable gain of a multi-stage according to another embodiment of the present invention.

7 is a structural diagram showing in detail the structure of a low noise amplification device having a multi-stage variable gain of FIG. 6 according to another embodiment of the present invention.

8 is a flow chart showing a multi-step variable gain providing method of a low noise amplifier according to another embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

300, 400, 600, 700: Low noise amplifier with variable gain

310, 610: input matching unit 320, 620: switching unit

330, 630: amplifier 340, 640: output matching unit

410, 710: transistor switch 420: BJT

720: MMIC

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication terminal, and more particularly, to a low noise amplifying apparatus having a multi-stage variable gain suitable for a receiver of a direct conversion method of a mobile communication terminal and a method thereof.

With the development of the mobile communication system and the development of mobile communication terminal manufacturing technology, mobile communication service subscribers are not satisfied with simply making a phone call while moving and want to be provided with a service having better call quality. Therefore, each mobile communication company spares no effort to improve the call quality. To improve the call quality, it is very important to improve the receiver performance in the mobile communication terminal in addition to the optimization of the mobile communication system. In the conventional mobile communication terminal, a receiver having a structure of a super heterodyne type is mainly used.

1 is a block diagram showing the configuration of a conventional super heterodyne receiver.

Referring to Figure 1, in the super heterodyne receiver amplified the ultra-high frequency signal received from the antenna 111 using the low noise amplifier 112, and then block the interference signal with the band filter 113 and down converter Use down 114 to downconvert to the intermediate frequency band. The band filter 116 blocks the interference signal included in the intermediate frequency signal. The intermediate frequency signal from which the interference signal is removed is converted into a baseband signal through the down converter 117 and then adjusted and output by the automatic gain control amplifier 118 to a constant amplitude, and this signal is output to the analog-digital converter 119. It is converted into a digital signal via.

The analog-to-digital converter 119 is generally inferior in linearity and is likely to malfunction due to saturation when an analog signal with a specific amplitude or more is input. Therefore, in the conventional superheterodyne system, the automatic gain control amplifier 118 is located in front of the analog-digital converter 119 and constantly adjusts the amplitude of the large and small analog signals and inputs the same to the analog-digital converter 119. I solved the same problem.

However, the superheterodyne scheme converts and amplifies to an intermediate frequency, so the sensitivity and selectivity are good, and the selectivity is good without sacrificing selectivity over a wide band, whereas the bit between the harmonic of the local oscillation frequency and the received radio wave ( beat) Easy to be disturbed, easy to receive video interference, complicated circuitry and difficult adjustment. In addition, due to components such as SAW filter or mixer required to convert to intermediate frequency, the weight and volume are increased, so there is a limit to use in a thinner and smaller mobile communication terminal.

Accordingly, a direct conversion method has been proposed, in which a carrier is directly lowered and raised to a baseband by removing an intermediate frequency conversion process in the super heterodyne method. This direct conversion method is difficult to use due to the low selectivity and sensitivity compared to the super heterodyne method, but since it does not require components necessary for intermediate frequency conversion, it is possible to reduce cost, weight, and system one chip. There is a strong advantage that it is suitable for use in mobile communication terminals. Therefore, research and practical use for improving the direct conversion scheme, including GSM (Global System for Mobile communications), in various ways to enable the use in mobile communication have been actively conducted, and continue to this day. The method is gradually being applied.

2 is a block diagram showing the configuration of the direct conversion receiver.

Referring to FIG. 2, the RF signal received from the antenna 211 is converted into a baseband signal at once without passing through the intermediate frequency band through the downlink converter 214 after passing through the band filter 213. The baseband signal is converted into a digital signal through an analog-to-digital converter 216. The band filter 217 and the automatic gain control amplifier 218 for blocking the interference signal of the baseband signal are located in the digital domain. As described above, in the direct conversion receiver, since the auto gain control amplifier 218 is positioned in the digital region after passing through the analog-to-digital converter 216, a signal having a large amplitude is input to the input of the analog-to-digital converter 216. To prevent this, a variable gain low noise amplifier 212 that variably adjusts the gain of the low noise amplifier of the RF stage is used to keep the amplitude of the signal input to the analog-to-digital converter 216 constant.

However, all of the low noise amplifiers having the variable gains as described above are implemented as expensive integrated circuits, and thus, there is a problem that it becomes a detrimental factor to lower the unit cost of the mobile communication terminal.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a low noise amplifying apparatus and method having a multi-stage variable gain suitable for a direct conversion receiver of a mobile communication terminal.

Another object of the present invention is to provide a low noise amplifying apparatus and method having a multi-stage variable gain that can be implemented using low cost general purpose components.

It is still another object of the present invention to provide a low noise amplification apparatus and method having a multi-stage variable gain designed to be suitable for cellular and PCS bands.

In order to achieve the above object, a low-noise amplifier having a multi-stage variable gain according to the present invention, the input matching unit for matching and outputting the input high frequency signal; A switching unit controlling a power output according to the level of the enable signal PLNA_EN; An amplifier having a gain of two stages and receiving an output of the input matching unit and performing an amplification having different gains depending on whether the switching unit is powered; And an output matching unit for matching and outputting the output of the amplifying unit.

In order to achieve the above object, the multi-stage variable gain providing method of the low noise amplifying apparatus according to the present invention comprises the steps of determining whether the magnitude of the signal input to the detector is more than a predetermined level; Setting the amplifier to a low gain mode by outputting a logic low to the enable (PLNA_EN) pin if the determination result is greater than or equal to a predetermined level; As a result of the determination, if the level is less than a predetermined level, a logic high (Logic High) is output to the enable pin.

In order to achieve the above object, a low-noise amplifier having a multi-stage variable gain according to the present invention, the input matching unit for matching and outputting the input high frequency signal; A switching unit controlling a power output according to the level of the enable signal CLNA_EN; An amplifying unit having three stages of gain and receiving an output of the input matching unit and performing an amplification to vary the gain depending on whether the switching unit is powered or not and the output of the amplifier range signal; And an output matching unit for matching and outputting the output of the amplifying unit.

In order to achieve the above object, the multi-stage variable gain providing method of the low noise amplifying apparatus according to the present invention comprises the steps of determining whether the magnitude of the signal input to the detector is greater than or equal to the first level; Setting the amplifier to a low gain mode by outputting a logic low to the enable pin CLNA_EN when the determination result is greater than or equal to the first level; Determining that the second level is greater than or equal to the second level if the determination result is less than the first level; As a result of the determination, outputting a logic high to the enable pin and a logic low to the amplifier range pin if the second level is equal to or higher, and setting the amplifier to the medium gain mode; The determination result; If the level is less than the second level, the logic pin is driven to the enable pin and the logic range is output to the amplifier range LNA_RANGE pin to set the amplifier to a high gain mode.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

In describing the present invention, when it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

3 is a structural diagram showing a structure of a low noise amplifying apparatus having a variable gain of multiple stages according to an embodiment of the present invention.

As shown in FIG. 3, the low noise amplifier 300 includes an input matching unit 310 for matching and outputting an input radio frequency (RF) signal; A switching unit 320 for controlling a power output according to a level of an enable signal (PLNA_EN: PCS band Low Noise Amplifier Enable) (or PCS enable signal); An amplifying unit (330) having a gain of two stages and amplifying the gain of the input matching unit (310) with a different gain depending on whether the switching unit (320) is powered; And an output matching unit 340 for matching and outputting the outputs of the amplifying unit 330.

The input matching unit 310 and the output matching unit 340 are composed of a plurality of capacitors, resistors, and inductors to match and output an input signal.

The switching unit 320 is composed of two transistors, when a high logic level signal (Logic High) is applied to the second terminal, the power supply Vcc of the third terminal is output to the fourth terminal, and a low logic level signal When (Logic Low) is applied, terminal 4 is blocked so power (Vcc) of terminal 3 is not discharged.

The PLNA_EN signal is a control unit (not shown) of the mobile communication terminal when the size of the signal input to the detector (see FIG. 2) is greater than or equal to a predetermined level to saturate the analog-to-digital converter (see FIG. 2). The switching unit 320 outputs the logic low by the low logic level and the PLNA_EN signal of the low logic level is applied to block the terminal 4 so that the power Vcc of the terminal 3 is not discharged.

On the other hand, if the magnitude of the signal input to the detector is less than a predetermined level, the PLNA_EN signal is output to the logic high (Logic High) by the control unit of the mobile communication terminal, the switching unit 320 to which the PLNA_EN signal of the high logic level is applied ) Outputs power supply 3 of terminal 3 to terminal 4.

The amplifier 330 is composed of a transistor such as a bipolar junction transistor (BJT). When the power output from the switching unit 320 is applied, the amplifier 330 operates in a high gain mode to have a gain of about 16 dB. When the power is cut off from the switching unit 320 and the power is not applied, the switching unit 320 operates in a low gain mode and has a gain of about -20 dB, that is, attenuation of about 20 dB.

That is, when the high frequency signal input through the antenna is a predetermined level or more (a size sufficient to saturate the analog-to-digital converter of the receiver), the PLNA_EN signal is output to the logic low by the control unit of the mobile communication terminal and the low logic level The switching unit 320 to which the PLNA_EN signal is applied blocks the terminal 4 so that the power supply Vcc of the terminal 3 is not discharged. Accordingly, the amplifying unit 330 to which power is not applied operates in a low gain mode to have a gain of about -20 dB, that is, attenuation of about 20 dB, thereby sufficiently attenuating the input signal to provide an analog-to-digital converter. Prevent saturation

On the other hand, when the high frequency signal input through the antenna is less than the predetermined level, the PLNA_EN signal is output to the logic high by the control unit of the mobile communication terminal, the switching unit 320 to which the PLNA_EN signal of the high logic level is applied is terminal 3 Output power (Vcc) to terminal 4. Accordingly, the amplifier 330 to which power is applied is operated in the high gain mode to sufficiently amplify the input signal.

4 is a structural diagram illustrating in more detail the structure of a low noise amplifying device having a variable gain of multiple stages of FIG. 3 according to an embodiment of the present invention.

As shown in FIG. 4, the low noise amplifier 400 having the multi-stage variable gain according to the present invention is composed of resistors, capacitors, inductors, and transistors, which are all low-cost components readily available on the market. 2, the amplification gain of the BJT 420 is adjusted by performing power supply control according to the logic level of the PLNA_EN signal with the transistor switch 410 corresponding to the switching unit 320 of FIG. 2.

The BJT 420 corresponds to the amplifier 330 of FIG. 2. As described above, when the size of the signal input to the detector is less than a predetermined level, the transistor passes the power by receiving a PLNA_EN signal having a high logic level. When the power is supplied by the switch 410 to operate in a high gain mode to amplify the input signal, and when the magnitude of the signal input to the detector is less than a predetermined level, the PLNA_EN signal having a low logic level is applied to cut off the power. If the power supply is not applied by the transistor switch 410, it operates in a low gain mode to sufficiently attenuate the input signal to prevent saturation of the analog-to-digital converter.

5 is a flowchart illustrating a multi-step variable gain providing method of a low noise amplifier according to an embodiment of the present invention.

As shown in FIG. 5, the multi-stage variable gain providing method of the low noise amplifying apparatus may include determining whether a magnitude of a signal input to the detector is greater than or equal to a predetermined level (S510); (S520 and S530) setting the amplifier to a low gain mode by outputting a logic low to the enable signal PLNA_EN pin when the determination result is greater than or equal to a predetermined level; As a result of the determination, if the level is less than the predetermined level, a logic high is output to the PLNA_EN pin to set the amplifier to the high gain mode (S540 and S550).

6 is a structural diagram illustrating a structure of a low noise amplifying apparatus having a variable gain of multiple stages according to another exemplary embodiment of the present invention.

As shown in FIG. 6, the low noise amplifier 600 includes an input matching unit 610 for matching and outputting an input RF signal; A switching unit 620 for controlling a power output according to a level of an enable signal CLNA_EN (or a cellular enable signal for cellular); It has three stages of gain, and receives the output of the input matching unit 610 and amplifies the gain according to the output of the switching unit 620 and the amplifier range (LNA_RANGE: Low Noise Amplifier Range) signal. An amplifier 630 for performing; And an output matching unit 640 for matching and outputting the output of the amplifier.

The input matching unit 610 and the output matching unit 640 are composed of a plurality of capacitors, resistors, and inductors to match and output an input signal.

The switching unit 620 is composed of two transistors, when a high logic level signal (Logic High) is applied to the second terminal, the power supply Vcc of the third terminal is output to the fourth terminal, and a low logic level signal When (Logic Low) is applied, terminal 4 is blocked so power (Vcc) of terminal 3 is not discharged.

The CLNA_EN signal is output to the logic low level by the controller of the mobile communication terminal when the size of the signal input to the detector is greater than or equal to the first level to saturate the analog-to-digital converter. The applied switching unit 620 blocks terminal 4 so that power Vcc of the terminal 3 is not discharged. At this time, the output of the LNA_RANGE signal is not correlated.

On the other hand, if the magnitude of the signal input to the detector is less than the first level, the CLNA_EN signal is output at a logic high by the controller of the mobile communication terminal, and the switching unit 620 to which the CLNA_EN signal of the high logic level is applied is 3; Output power (Vcc) of terminal # 1 to terminal # 4.

The LNA_RANGE signal is output at a logic high by the controller of the mobile communication terminal when the low noise amplifier 600 needs to be operated in the high gain mode because the signal input to the detector is less than the second level. If the magnitude of the signal is less than the first level and not less than two levels, i.e., the magnitude of the input signal is not large enough to saturate the analog-to-digital converter but small enough to operate in a high gain mode, by the control unit of the mobile communication terminal. Output to logic low.

The amplifier 630 is composed of a low-cost circuit having a two-stage gain, such as MMIC (Monolithic Microwave Integrated Circuit), when the power is cut off by the switching unit 620, that is, terminals 1, 4 When the power applied to is cut off, it is set to a low gain mode having a gain of about -20dB regardless of the output of the LNA_RANGE signal.

In addition, the amplifier 630 is set to a high gain mode having a gain of about 16dB when power is applied through the switching unit 620 and logic high is applied to terminal 6, and when logic low is applied,- The mode is set to medium gain with a gain of 2dB.

That is, when a signal large enough to saturate the analog-to-digital converter of the receiver is input, the controller of the mobile communication terminal determines that the magnitude of the input signal is greater than or equal to the first level, and outputs the CLNA_EN signal as a logic low, and the low logic. The switching unit 620 to which the CLNA_EN signal of the level is applied blocks the terminal 4 so that the power Vcc of the terminal 3 is not discharged. Accordingly, the amplifier 630, in which power is not applied to the terminals 1 and 4, operates in a low gain mode and operates to have a gain of about -20 dB, that is, attenuation of about 20 dB, so that the input signal can be sufficiently operated. Attenuation prevents saturation of the analog-to-digital converter.

On the other hand, when the magnitude of the input signal is less than the first level, the controller of the mobile communication terminal outputs the CLNA_EN signal to logic high, and the switching unit 620 to which the CLNA_EN signal of the high logic level is applied is the power source of terminal 3 Output (Vcc) to terminal 4. Accordingly, power is applied to terminals 1 and 4 of the amplifier 630.

At this time, when the magnitude of the input signal is less than the second level, the controller of the mobile communication terminal outputs the LNA_RANGE signal to logic high and the amplifier 630 applied to the LNA_RANGE signal of the high logic level to terminal 6 is in the high gain mode. In this case, the input signal is amplified to a sufficient size.

However, when the magnitude of the input signal is greater than or equal to the second level (more than or equal to the second level and less than the first level), the controller of the mobile communication terminal outputs the LNA_RANGE signal to logic low and outputs the LNA_RANGE signal of the low logic level six times. The amplifier 630 applied to the terminal operates in a medium gain mode to perform amplification with a gain of an appropriate magnitude.

7 is a structural diagram illustrating in more detail the structure of a low noise amplifying device having a variable gain of FIG. 6 according to another embodiment of the present invention.

As shown in FIG. 7, the amplification apparatus is composed of resistors, capacitors, inductors, transistors, and MMICs 720 which are all low-cost components readily available on the market. In particular, the switching unit 620 of FIG. Power control according to the logic level of the CLNA_EN signal is performed by the transistor switch 710 corresponding to the < RTI ID = 0.0 >

The MMIC 720 corresponds to the amplifier 630 of FIG. 6. As described above, when the magnitude of the signal input to the detector is greater than or equal to the first level, the MMIC 720 receives a CLNA_EN signal having a low logic level to cut off power. If power is not applied by the transistor switch 710, the device operates in a low gain mode to sufficiently attenuate the input signal to prevent saturation of the analog-to-digital converter. In addition, when the size of the signal input to the detector is less than the first level and the second level or more, the power is supplied by the transistor switch 710 that passes the power by receiving the CLNA_EN signal of the high logic level, the low logic level of When the LNA_RANGE signal is applied, it operates in the medium gain mode and amplifies the input signal. In addition, when the magnitude of the signal input to the detector is less than the second level, the power is supplied by the transistor switch 710 which passes the power by receiving the CLNA_EN signal of the high logic level, and receives the LNA_RANGE signal of the low logic level. In this case, the amplification of the input signal is performed by operating in the high gain mode.

8 is a flowchart illustrating a multi-step variable gain providing method of a low noise amplifying apparatus according to another embodiment of the present invention.

As shown in FIG. 8, the multi-stage variable gain providing method of the low noise amplifying apparatus may include determining whether a magnitude of a signal input to the detector is equal to or greater than a first level (S810); Setting the amplifier to a low gain mode by outputting a logic low to the CLNA_EN pin as a result of the determination (S820, S830); Determining whether it is greater than or equal to the second level if it is less than the first level (S840); As a result of the determination, outputting a logic high to the CLNA_EN pin and a logic low to the LNA_RANGE pin if the second level is equal to or higher than the second level (S850 and S860); The determination result; If it is less than the second level, a logic high is output to the CLNA_EN pin and a logic high is output to the LNA_RANGE pin to set the amplifier to the high gain mode (S870 and S880).

In addition, although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the multi-stage low-noise amplification apparatus and method according to the present invention can easily obtain a low-noise amplifier having a variable gain required in a direct conversion receiver without using expensive integrated circuits. There is an effect that can be implemented using low-cost parts.

In addition, low noise amplification by two stages of variable gain is suitable for PCS band receivers without intermodulation distortion test, and low noise amplification by three stages of variable gain is suitable for cellular band receivers where improvement of intermodulation distortion characteristics is essential. Therefore, there is an effect that it can be widely applied to various reception methods having different bands.

Claims (35)

An input matching unit for matching a high frequency signal input through an antenna; A switching unit controlling a power output according to the level of the input high frequency signal; An amplifying unit for amplifying the high frequency signal matched by the input matching unit with a multi-step gain according to the output power of the switching unit; And an output matching unit for matching the high frequency signal amplified by the amplifier and outputting the detector to the detector. The amplification unit operates in a low gain mode when the high frequency signal is at a predetermined level and power is not applied from the switching unit. The amplification unit operates in a high gain mode when the high frequency signal is less than a predetermined level and power is applied from the switching unit. A low noise amplifying device having a variable gain of multiple stages. The method of claim 1, wherein the input matching unit and the output matching unit A low noise amplifying device having a variable gain of a multi-stage, characterized in that the input signal consisting of a plurality of capacitors, resistors, inductors to match and output. The method of claim 1, wherein the low gain mode And a high gain mode is a mode for performing amplification with a gain of about 16 dB. delete delete delete delete delete delete delete delete delete Determining whether the magnitude of the high frequency signal input through the antenna and output to the detector is greater than or equal to a predetermined level; Operating the amplifier in a low gain mode by preventing power from being applied to the amplifier if the magnitude of the high frequency signal is greater than or equal to a predetermined level as a result of the determination; And operating the amplifier in a high gain mode by applying power to the amplifier if the magnitude of the high frequency signal is less than or equal to a predetermined level. delete delete An input matching unit for matching a high frequency signal input through an antenna; A switching unit for controlling a power output according to a level of an enable signal output from a controller corresponding to the level of the high frequency signal; An amplifier for amplifying the high frequency signal matched by the input matching unit with a multi-step gain according to the output power of the switching unit and the level of the high frequency signal; And an output matching unit for matching the high frequency signal amplified by the amplifier and outputting the detector to the detector. The amplifier is operated in a low gain mode because the power is not output from the switching unit when the level of the high frequency signal is greater than or equal to the first level, and is output from the switching unit when the level of the high frequency signal is less than or equal to the second level less than the first level. The low noise amplifying device having a variable gain of the multi-stage, characterized in that it operates in a medium gain mode according to the supplied power, and operates in a high gain mode according to the power output from the switching unit if the level of the high frequency signal is less than the second level. . delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete Determining whether the magnitude of the high frequency signal input through the antenna and output to the detector is equal to or greater than a first level; Operating the amplifier in a low gain mode by outputting a logic low to an enable pin if the magnitude of the high frequency signal is greater than or equal to a first level; Determining whether the high frequency signal is less than a first level if the magnitude of the high frequency signal is less than a first level; Operating the amplifier in a medium gain mode by outputting a logic high to the enable pin and a logic low to an amplifier range pin when the magnitude of the high frequency signal is greater than or equal to a second level; And outputting a logic high to the enable pin and outputting a logic high to the amplifier range pin if the magnitude of the high frequency signal is less than a second level, thereby operating the amplifier in a high gain mode. Method of providing multi-level variable gain of device. delete delete delete

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