KR100997665B1 - Apparatus for optimizing electronic characteristics of low noise amplifier in mobile communication terminal - Google Patents

Abstract

The present invention relates to an apparatus for optimizing the characteristics of a low noise amplifier in a mobile communication terminal. According to the present invention, the apparatus for optimizing the characteristics of the low noise amplifier in the mobile communication terminal, a plurality of input matching parts for the input matching of the low noise amplifier, the first switch is provided in front of the plurality of input matching parts and A second switch connected between the plurality of input matching units and the low noise amplifier, a plurality of output matching units for output matching of the low noise amplifier, and a second connection between the low noise amplifier and the plurality of output matching units A third switch, a fourth switch installed at the rear end of the plurality of output matching units, and a voltage for controlling gain according to a reception electric field to the low noise amplifier, and an input matching signal for which a received signal is optimally designed at the applied voltage. And a control unit controlling the first to fourth switches to pass through a unit and an output matching unit.

Low Noise Amplifier, Input / Output Matching, IIP3, NF, Current Consumption, Gain

Description

Apparatus for optimizing the characteristics of low noise amplifier in mobile communication terminal {APPARATUS FOR OPTIMIZING ELECTRONIC CHARACTERISTICS OF LOW NOISE AMPLIFIER IN MOBILE COMMUNICATION TERMINAL}             

1 is a view showing the configuration of a low noise amplifier using a conversion gain (STEP-GAIN) according to the prior art.

2 is a view showing the configuration of a radio frequency (RF) transmitter of a general mobile communication terminal.

3 is a view showing the configuration of a low noise amplifier circuit according to an embodiment of the present invention.

The present invention relates to a receiver of a mobile communication terminal, and more particularly, to an apparatus for optimizing the electronic characteristics of a low noise amplifier.

In general, a mobile communication terminal uses a low noise amplifier (LNA) for amplifying a weak received signal while suppressing noise. The low noise amplifier requires high gain and stability while satisfying a low noise figure (NF).

The explosive increase in the number of terminals has continuously demanded an improvement in reception quality. For this reason, the characteristics of the low noise amplifier also progressed to the improvement of the input third order intercept point (IIP3) at the initial high gain and the low noise characteristics, and further required the high IIP3 in the strong and medium electric fields. The IIP3 is an input power value at a point where the two powers are equal under the assumption that the original signal (fundamental output power) and the third-order intermodulation (IM3) component continue to increase without being saturated. In general, the IIP3 is mainly used as an index for measuring the linearity of the device, the higher the value.

Currently, a method of changing the voltage (gain) applied to the low noise amplifier, increasing the amount of current, and improving IIP3 is widely used to improve characteristics of the strong and medium electric fields. However, this method cannot take into account the noise figure (NF) and the optimum amount of current. Basically, active devices such as transistors and field effect transistors (FETs) have different input and output S (scattering) parameters depending on the applied voltage, so that it is impossible to implement an optimal input / output matching circuit at different voltages. Do. Here, the S parameter is a value representing the ratio of the input voltage to the output voltage. In particular, when optimization of current consumption is becoming increasingly important, it is more difficult to implement a circuit that optimizes not only gain and IIP3 but also current consumption and noise figure.

In general, the reception field characteristic of the terminal has a dynamic range of 80 dB from -25 dBm to -105 dBm. As mentioned above, the low noise amplifier, which is optimized in the current weak electric field, uses a method of lowering gain by applying a gain gain (STEP-GAIN) to the low noise amplifier in order to operate effectively in a strong electric field.

1 shows a configuration of a low noise amplifier circuit using a conversion gain according to the prior art.

As shown, the low noise amplifier circuit according to the prior art is composed of an input matching circuit 101, a low noise amplifier 102, an output matching unit 103 and a gain adjusting unit 104. Here, the input matching circuit 101, the low noise amplifier 102 and the output matching section 103 are optimized to have low noise characteristics, high gain and high IIP3. Therefore, the gain adjusting unit 104 adjusts the gain of the low noise amplifier 102 according to the received electric field so as to operate effectively to some extent even in a strong electric field. At this time, the gain and the amount of change are not set to satisfy the optimum requirements in the strong electric field or the weak field, but are set in a direction satisfying the minimum condition. In particular, this method is currently applied to the DCR (Direct Conversion Receiver) method, and implements high IIP3 characteristics by adjusting the gain according to each electric field.

However, although the conversion gain method can realize a high IIP3 according to the electric field range to be applied, the characteristics of the low noise amplifier can be deteriorated because the input / output matching circuit and the current amount which are suitable for the optimum noise level cannot be optimized. There is this. In particular, the input and output characteristics of the low noise amplifier change according to the applied voltage, and if the applied voltage is adjusted, the gain and current amount can be adjusted so that the IIP3 characteristics can be controlled, but the optimum gain and noise are not optimized because the input / output matching circuit is not optimized. There is a problem that both the exponent and the conditions such as the optimization of high IIP3 and the amount of current cannot be satisfied.

Accordingly, an object of the present invention is to provide an apparatus for optimizing the characteristics of a low noise amplifier in all receiving fields in a mobile communication terminal.

Another object of the present invention is to provide an apparatus for a low noise amplifier using conversion gain to satisfy an optimum gain, noise figure, current amount, and IIP3 characteristics in all receiving fields.

It is still another object of the present invention to provide an apparatus for selectively using an input / output matching circuit for a low noise amplifier using conversion gain and selectively using the received electric field.

According to an aspect of the present invention for achieving the above object, the apparatus for optimizing the characteristics of the low noise amplifier in the mobile communication terminal, a plurality of input matching parts for the input matching of the low noise amplifier, and the plurality of input matching parts A first switch installed at a front end, a second switch connected between the plurality of input matching parts and the low noise amplifier, a plurality of output matching parts for output matching of the low noise amplifier, the low noise amplifier and the plurality of A third switch connected between the output matching units, a fourth switch installed at the rear end of the plurality of output matching units, and a voltage for controlling gain according to a reception electric field to the low noise amplifier, and the receiving signal is applied to the low noise amplifier. A control unit controlling the first to fourth switches to pass through the input matching unit and the output matching unit optimally designed at the voltage Characterized in that it comprises a.

Preferably, each of the plurality of input matching units and the plurality of output matching units has an optimum input third order intercept point (IIP3), an optimum noise figure, and an optimum current consumption at a corresponding gain control voltage. It is characterized in that it is designed to have.
According to another aspect of the present invention, in a reception apparatus of a mobile communication terminal, a reception intensity measuring unit for measuring the signal strength of a received signal, and controlling the gain of the low noise amplifier according to the measured signal strength, A control unit for selecting one of the at least two input / output matching circuits of the low noise amplifier according to signal strength, the at least two input / output matching circuits and the low noise amplifier unit, and the received signal under the control of the control unit It characterized in that it comprises a low noise amplification circuit portion which is operated to pass through the selected input and output matching circuit of the input and output matching circuit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In describing the present invention, if 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.

Hereinafter, a description will be given of a technique for optimizing characteristics of a low noise amplifier (LNA) using a conversion gain (STEP-GAIN) in all receiving fields in a mobile communication terminal. In other words, we will discuss techniques for optimizing the optimum gain, noise figure and high IIP3 and current consumption in all received fields.

Figure 2 shows the configuration of a radio frequency (RF) receiver of a typical mobile communication terminal.

As illustrated, the RF receiver of the mobile communication terminal includes a band pass filter 200, a low noise amplifier 201, a band pass filter 202, a mixer 203, a phase locked loop (PLL) ( 204, a local oscillator (LO) 205, an amplifier 207, a mixer 208, and a local oscillator 209.

Referring to FIG. 2, the antenna first receives an electromagnetic wave signal in the air and converts the signal into an electrical signal on a wire. The band pass filter 200 filters and outputs only signals of a desired frequency band from the signal received by the antenna. In this case, when multiple channels are used, all of the channels must be passed in-band. In general, when the same antenna is used, a duplexer serves as a duplexer.

The low noise amplifier 201 amplifies and outputs the signal from the band pass filter 200 while suppressing amplification to noise as much as possible. The low noise amplifier 201 according to the present invention will be described in detail with reference to FIG. 3.

The bandpass filter 202 performs the bandpass filtering once again to prevent the lethal image frequency from being transmitted to the mixer among the signals amplified by the low noise amplifier 201. In addition, spurious frequencies are removed, and the RF and IF stages are separated to achieve stability of the receiver.

The phase locked loop 204 serves to lock the output frequency of the local oscillator 205 so that it can be fixed at a constant frequency without shaking. The local oscillator 205 generates a local oscillation (LO) frequency for converting an RF signal into an intermediate frequency (IF) signal. The mixer 203 mixes the signal from the bandpass filter 202 and the local oscillation frequency generated by the local oscillator 205 and down-converts the RF signal to the IF band for output.

The band pass filter 206 outputs only the band of the desired channel in the signal from the mixer 203. Here, a filter having good skirt characteristics is used because the gap between channels is narrow. The amplifier 207 amplifies and outputs the channel signal from the band pass filter 206.

The local oscillator 207 generates a local oscillation (LO) frequency for converting the IF signal into a baseband signal. The mixer 208 mixes the signal from the amplifier 207 and the local oscillation frequency generated by the local oscillator 207 and down-converts the IF signal into a baseband signal for output.

3 illustrates a configuration of the low noise amplifier 201 according to an embodiment of the present invention.

As shown, the low noise amplifier 201 according to the present invention includes a first switch 303, a first input matching unit 304, a second input matching unit 305, a second switch 306, and a low noise amplifier. 307, a third switch 308, a first output matching unit 309, a second output matching unit 310, and a fourth switch 311. In order to control the low noise amplifier 201, a controller 300, a memory 301, and a received signal strength indicator (RSSI) 302 are configured.

Referring to FIG. 3, first, the controller 300 controls the overall operation of the mobile communication terminal. In particular, according to the present invention, the control unit 300 controls the switching operation of the first to fourth switches 303, 306, 308 and 311 according to the received electric field measured by the received signal strength measuring instrument 302, and the gain of the low noise amplifier 307. A voltage for adjusting the gain is output to the low noise amplifier 307. The controller 300 is typically a one chip microprocessor, and may use, for example, a mobile station modem (MSM) chip manufactured by Qualcomm.

The memory 301 includes a volatile memory (eg, RAM) and a nonvolatile memory (eg, flash memory, EEPROM), and is generated according to program data, initial service data, and performance of an operation for controlling the overall operation of the mobile communication terminal. Store temporary data. In particular, according to the present invention, the memory 301 includes a table for storing the gain control voltage value of the low noise amplifier 307 according to the received electric field.

The reception intensity measuring unit 302 measures the signal strength of the baseband signal output from the mixer 208 and outputs the signal strength to the control unit 300.

The first switch 303 is switched under the control of the controller 300 to transfer a signal from the band pass filter 200 to the first input matching unit 304 or the second input matching unit 305. The first input matching unit 304 represents an input matching circuit optimized in the weak electric field. That is, it is an input matching circuit implemented to have optimum IIP3, noise figure (NF), and current consumption for high gain. The second input matching unit 304 represents an input matching circuit optimized in a strong electric field, and is an input matching circuit implemented to have an optimal IIP3, a noise figure (NF), and a current consumption for a low gain.

The second switch 306 is switched under the control of the controller 300 to transmit a signal from the first input matching unit 304 or the second input matching unit 305 to the low noise amplifier 307. The low noise amplifier 307 amplifies and outputs an input signal while suppressing noise.

The third switch 308 is switched under the control of the controller 300 to transfer the output signal of the low noise amplifier 307 to the first output matching unit 309 or the second output matching unit 310. The first output matching unit 304 represents an output matching circuit optimized in the weak electric field, and is an output matching circuit implemented to have an optimal IIP3, a noise figure (NF), and a current consumption for high gain. The first output matching unit 310 represents an output matching circuit optimized in a strong electric field, and is an output matching circuit implemented to have an optimum IIP3, a noise figure (NF), and a current consumption for a low gain.

The fourth switch 311 is switched under the control of the controller 300 to output a signal from the first output matching unit 309 or the second output matching unit 310 to the band pass filter 202.

As described above, the controller 300 checks the current reception electric field, and if the received signal is a weak electric field according to the reception electric field, the received signal passes through the first input matching unit 304 and the first output matching unit 309. The first to fourth switches are controlled, and in the case of a strong electric field, the first to fourth switches are controlled such that the received signal passes through the second input matching unit 304 and the second output matching unit 310.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. As an example, the embodiment of the present invention has been described as using two input and output matching circuits (weak electric field and strong electric field), but may be implemented as two or more if necessary. 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, the present invention implements a plurality of input / output matching circuits for the low noise amplifier and selectively uses them according to the reception field, so that the low noise amplifier has the optimum gain, IIP3, and noise index for all the reception fields. NF) and current consumption can be secured. That is, it has the effect of optimizing the characteristics of the low noise amplifier in all receiving fields.

Claims (10)

In the device for optimizing the characteristics of the low noise amplifier in the mobile communication terminal, A plurality of input matching units for input matching of the low noise amplifier, A first switch installed in front of the plurality of input matching parts; A second switch connected between the plurality of input matching units and the low noise amplifier; A plurality of output matching units for output matching of the low noise amplifier, A third switch connected between the low noise amplifier and the plurality of output matching units; A fourth switch installed at a rear end of the plurality of output matching units; A controller for applying a voltage for controlling gain according to a reception electric field to the low noise amplifier, and controlling the first to fourth switches such that a received signal passes through an input matching unit and an output matching unit optimally designed at the applied voltage. Apparatus comprising a. The method of claim 1, Each of the plurality of input matching units and the plurality of output matching units has an optimal input third order intercept point (IIP3), an optimum noise figure (NF: noise figure), and an optimum current consumption at a corresponding gain control voltage. Apparatus characterized in that it is designed to. The method of claim 1, Apparatus further comprising a reception intensity measuring unit for measuring the received electric field. The method of claim 1, The plurality of input matching units include an input matching unit for at least one weak field and an input matching unit for at least one strong field. The method of claim 1, And the plurality of output matching units includes an output matching unit for at least one weak field and an output matching unit for at least one strong field. In the receiving device of a mobile communication terminal, A reception strength measuring unit for measuring signal strength of a reception signal; A control unit controlling gain of the low noise amplifier according to the measured signal strength, and selecting one of at least two input / output matching circuits of the low noise amplifier according to the measured signal strength; And a low noise amplifier circuit including the at least two input / output matching circuits and the low noise amplifier, the low noise amplifier circuit being controlled so that a received signal is passed through an input / output matching circuit selected from the at least two input / output matching circuits under the control of the controller. Device. The method of claim 6, And a memory storing a gain control value of the low voltage amplifier according to the signal strength of the received signal. The method of claim 6, wherein the low noise amplifier circuit portion, The low noise amplifier, A plurality of input matching units for input matching of the low noise amplifier, A first switch installed in front of the plurality of input matching parts; A second switch connected between the plurality of input matching units and the low noise amplifier; A plurality of output matching units for output matching of the low noise amplifier, A third switch connected between the low noise amplifier and the plurality of output matching units; A fourth switch installed at a rear end of the plurality of output matching units, And the first to fourth switches perform a switching operation under the control of the controller. The method of claim 8, And the plurality of input matching units includes an input matching unit for at least one weak field and an input matching unit for at least one strong field. The method of claim 8, And the plurality of output matching units includes an output matching unit for at least one weak field and an output matching unit for at least one strong field.

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