KR100691047B1 - Output terminal matching device of mobile communication terminal - Google Patents

Abstract

The present invention relates to an output terminal matching circuit of a mobile communication terminal transmitting terminal for output impedance varying according to a change in battery voltage, so that the transmission terminal can satisfy both efficiency characteristics and adjacent channel power saving characteristics.

To this end, the present invention, in the output terminal matching device of the transmitter of the mobile communication terminal having a voltage amplifier module (PAM) for adjusting the input signal to a predetermined gain characteristics, the output impedance is connected to the output terminal of the PAM variable according to the battery voltage An output stage matching circuit for generating a; An output impedance adjuster for adjusting the output impedance based on the battery voltage; And connected between an output terminal of the PAM and an output terminal of the output impedance adjusting unit, applying a voltage output from the output impedance adjusting unit to the output terminal matching circuit, and blocking the output voltage of the PAM from flowing backward to the output impedance adjusting unit. It is characterized by comprising a reverse flow blocking unit.

Description

OUTPUT IMPEDANCE MATCHING DEVICE OF TRANSMITTER OF MOBILE PHONE}

1 is a diagram illustrating an output terminal matching circuit of a conventional mobile communication terminal transmitting terminal.

2 and 3 are load pull data graphs of a power amplifier module (PAM).

4 is a block diagram of an output terminal matching device of a mobile communication terminal transmitting terminal according to an embodiment of the present invention.

5 is a circuit diagram of a varactor diode applied to an embodiment of the present invention.

6 is a characteristic graph of a varactor diode applied to an embodiment of the present invention.

7 is a load-pull data graph illustrating a change in output impedance by an output terminal matching device of a mobile terminal in accordance with an embodiment of the present invention.

8 is a block diagram of an output terminal matching device of a mobile communication terminal transmitting terminal according to another embodiment of the present invention.

** Description of symbols for the main parts of the drawing **

10: power amplifier module (PAM) 20,50,500: output stage matching circuit

25: control unit 30: power supply unit

40,400: reverse flow block 100: filter

C1, C2, C3: Capacitors L1, L2, L3: Inductors

D, D1: Variant Diode

The present invention relates to an output terminal matching circuit of a mobile communication terminal transmission terminal, and more particularly, to a technology in which a matching circuit impedance of a power amplifier module (PAM) is actively changed according to a change in battery voltage.

Referring to the process of RF transmission operation of a conventional wireless mobile communication terminal, the voice signal is first converted from a microphone to an electric signal, and then the converted electric signal is coded for digital communication. Thereafter, the coded voice signal is converted into an analog signal again, and the analog signal of the low frequency band is amplified. The low frequency band analog signal is converted to high frequency using a mixer, a local oscillator, and a phase locked loop (PLL).

In this case, a drive amplifier is provided to amplify the output signal of the mixer, and the drive amplifier is positioned between a power amplifier module (PAM) and a transmission PLL, and outputs the transmission PLL. Since the level is low, it serves to amplify the signal to the input level required by the PAM.

In PAM, the insertion loss of input / output matching circuit and duplexer located between PAM and antenna is taken into consideration, and the PAM signal of the receiving channel is shared with the antenna through the duplexer. Note that the effect is amplified by the terminal output power according to the regulations, and the duplexer selectively radiates the transmission band to the antenna.

Hereinafter, an output matching circuit of a conventional mobile communication terminal transmitter will be described with reference to FIG. 1.

As shown in FIG. 1, in the output stage matching circuit 20, a series inductor L1 is connected to an output terminal of a PAM 10 that amplifies an input signal with its gain characteristics, and parallel to both ends of the series inductor L1. The low capacitors C1 and C2 are connected, respectively, and perform a function of performing impedance matching on the output signal from the PAM 10.

Here, since the inductor L1 and the capacitors C1 and C2 each use a fixed value, they always have a constant output impedance regardless of the surrounding situation.

On the other hand, the PAM 10 changes the load-pull according to the battery voltage. When the battery voltage is high (for example, 4V or more), the load-pull data as shown in FIG. data) and load-pull data as shown in FIG. 3 when the battery voltage is low (for example, 3. V or less).

According to the load-pull data shown in FIG. 2, a circle B1 indicating the degree of adjacent channel power blocking ACPR and a circle A1 indicating the degree of efficiency are configured, and adjacent to the adjacent channel power blocking circle B1. The point B2 with the highest channel power stop ACPR exists, and the point A2 with the highest efficiency exists in the efficiency circle A1.

2 and 3, since the efficiency circle A1 and the adjacent channel power blocking circle A2 are changed in accordance with the battery voltage, the PAM 10 changes the output impedance by the output matching circuit 20. In the state where Zout) is fixed, high battery voltage has high efficiency and good adjacent channel power saving characteristics, while low battery voltage decreases linearity and degrades adjacent channel power saving characteristics, thereby preventing high quality call service. .

In consideration of this characteristic, the output impedance Zout can be adjusted by adjusting the values of the capacitors C1 and C2 and the inductor L1 of the output matching circuit, but since the output impedance Zout is also fixed, the battery voltage In this changing state, there is a problem in that it cannot satisfy both the efficiency provided by the PAM and the power saving characteristics of the adjacent channel.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the output impedance of the mobile communication terminal can be changed according to the change of the battery voltage so that the mobile terminal can satisfy both the efficiency characteristics and the adjacent channel power saving characteristics. It is an object to provide an output stage matching circuit.

In order to achieve the above object, an output terminal matching device of a mobile communication terminal transmitting terminal according to the present invention is an output terminal matching device of a mobile communication terminal transmitting terminal having a voltage amplifier module (PAM) for adjusting an input signal to a predetermined gain characteristic. An output stage matching circuit connected to an output terminal of the PAM to generate an output impedance in accordance with a battery voltage; An output impedance adjuster for adjusting the output impedance based on the battery voltage; And connected between an output terminal of the PAM and an output terminal of the output impedance adjusting unit, applying a voltage output from the output impedance adjusting unit to the output terminal matching circuit, and blocking the output voltage of the PAM from flowing backward to the output impedance adjusting unit. Hindi comprising a back flow block.

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

4 is a block diagram of an output terminal matching device of a mobile communication terminal transmitting terminal according to an embodiment of the present invention.

As shown in FIG. 4, an output terminal matching device of a mobile terminal in accordance with an embodiment of the present invention includes a PAM 10, a control unit 25, a power supply unit 30, a reverse flow blocking circuit 40, and an output terminal. A matching circuit 50 is provided.

The battery voltage Vbat is applied to the controller 25 and the PAM 10, and the controller 25 measures the battery voltage Vbat and supplies a voltage adjustment signal having a level corresponding to the battery voltage Vbat. Output to (30). Preferably, the controller 25 corresponds to a voltage value that should be applied to the varactor diode D so that the varactor diode D, which will be described later, with respect to the measured battery voltage Vbat, can output an optimal capacitance. A table in which level information is stored is provided. The control unit 25 transmits a power adjustment signal corresponding to the level information to the power supply unit 30 so that the power supply unit 30 applies a predetermined voltage to the voltage detector (D) side.

When the voltage adjustment signal is transmitted from the control unit 25, the power supply unit 30 outputs a voltage corresponding to the voltage adjustment signal, and the voltage is applied to the varactor diode D through the backflow blocking circuit 40. . In this case, the voltage output from the power supply unit 30 and applied to the varactor diode D is a DC voltage. The power supply unit 30 may be configured as a digital analog converter (DAC).

On the other hand, the backflow prevention circuit 40 includes an inductor L2 between the power supply unit 30 and the diode D, and the capacitor C3 is disposed between the output terminal of the power supply unit 30 and the inductor L2. In addition, the AC voltage output from the PAM 10 serves to block backflow to the power supply unit 30. Preferably, the inductor L2 of the present invention is an RF choke RFC.

In addition, the output stage matching circuit 50 has one side connected between the inductor L1 connected to the output terminal of the PAM 10 and the output terminal of the PAM 10 and the inductor L1, and the other side connected to the ground terminal. A capacitor C2 is connected between the output of the inverter diode D and the inductor L1 and the ground terminal.

In the above-described structure, the AC voltage output from the PAM 10 is not applied to the power supply unit 30 by the backflow blocking circuit 40, but is applied to the inductor L1 side, and the DC output from the power supply unit 30. The voltage is applied to the varactor diode D via the reverse flow blocking circuit 40.

The varactor diode D applied in the present invention is configured as shown in FIG. 5 and has the characteristics as shown in FIG. 6.

The varactor diode D is a device in which a carrier is removed from a depletion layer of a pn junction so that the depletion layer acts as a dielectric (insulator). The pn junction forms a small capacitance capacitance. By this operation, the varactor diode D operates as a variable capacitor.

When the reverse bias is applied to the varactor diode D, the thickness of the depletion layer changes according to the magnitude of the voltage, and the capacitance changes. 6 is a graph showing the amount of change in capacitance with respect to the reverse bias value. According to FIG. 6, it can be seen that as the reverse vise voltage increases, the capacitance decreases. Therefore, by adjusting the reverse bias voltage applied to the varactor diode D, the capacitance applied to the varactor diode D can be adjusted.

Accordingly, in the present invention, when the battery voltage is higher than the threshold value, the output impedance Zout becomes Zout1, so that both the efficiency characteristic and the adjacent channel power suppression specification are good, and as the battery voltage decreases, the output impedance Zout becomes Zout2. Direction, so that the efficiency characteristics and the adjacent channel power blocking side can be maintained above a certain level even when the battery voltage is lowered. The change in output impedance Zout moves along the admittance circle as shown in FIG. 7. When the voltage applied to the varactor diode D is high, the output impedance becomes Zout1 and is applied to the varactor diode D. When the voltage drops, it changes to Zout2 along the admittance circle. On the contrary, when the battery becomes high in the voltage detector D while the output impedance is Zout2, the output impedance is changed in the Zout1 direction.

The positions of the output impedances Zout1 and Zout2 in the load-pull data are as shown in FIGS. 3 and 7.

In particular, as shown in FIG. 3, as the output impedance moves to Zout2 when the battery voltage is low, it can be seen that the adjacent channel power suppression (ACPR) characteristics are remarkably improved.

Next, an operation of the output terminal matching device of the mobile communication terminal transmitting terminal according to an embodiment of the present invention will be described.

 The battery voltage Vbat is applied to the controller 25 and the PAM 10, and the controller 25 measures the battery voltage Vbat and supplies a voltage adjustment signal having a level corresponding to the battery voltage Vbat. Output to (30).

At this time, the controller 25 transmits a power adjustment signal to the power supply unit 30 such that the reverse bias applied to the varactor diode D is lowered as the battery voltage Vbat is lowered. This means that the lower the reverse bias of the varactor diode D, the larger the capacitance, the larger the capacitance, the output impedance moves in the Zout2 direction, the higher the reverse bias of the varactor diode D, the smaller the capacitance, This is because the output impedance moves in the Zout1 direction as the capacitance becomes smaller.

Meanwhile, the output voltage of the PAM 10 is transmitted to the inductor L1, and the output impedance Zout generated by the varactor diode D and the capacitor C2 and the inductor L1 according to the battery voltage Vbat. ), It is possible to maximize the efficiency characteristics and the adjacent channel power saving characteristics in the PAM (10).

The output terminal matching device of the mobile communication terminal transmitter according to the embodiment of the present invention described above has a table for storing power control signal information according to the battery voltage in the controller 25, and the controller Since the power supply unit 30 for outputting the voltage corresponding to the power control signal under the control of 25 should be provided, there is an advantage that can precisely control the varactor diode (D), while the power supply unit 20 There is a disadvantage in that a circuit constituting) is further provided.

Thus, in order to compensate for the above disadvantage, the output terminal matching device of the mobile communication terminal transmitting terminal using a relatively simple resistance distribution circuit can be configured as another embodiment of the present invention.

As shown in FIG. 8, the output matching device of the transmitter of the mobile communication terminal according to another embodiment of the present invention includes a filter 100 that removes a ripple component from a battery voltage which becomes unstable by the operation of the PAM 10. ) Is connected to the output terminal of the filter 100 and outputs a predetermined voltage that is varied according to the battery voltage Vbat, and is connected between the output terminal of the common node A and the PAM 10 and the PAM. A reverse flow blocking circuit 400 for blocking a voltage output from the power supply unit 200 from flowing backward to the power supply unit 200 and an output matching circuit 500 connected to an output terminal of the PAM 10 to match an output impedance. .

The power supply unit 200 includes a resistance distribution circuit including a resistor R1 and a resistor R2 connected in series with the filter 100.

The output stage matching circuit 500 has one inductor (L1) connected to the output terminal of the PAM (10), the one side is connected between the output terminal of the PAM and the input terminal of the inductor (L1), the other side is a varactor diode connected to the ground terminal And a capacitor C2 connected between the output terminal of the inductor L1 and the ground terminal.

The reverse flow blocking circuit 400 is connected between the common node A of the resistor R1 and the resistor R2 and the PAM 10 to prevent the reverse flow of the voltage output from the PAM 10. And a capacitor C4 connected between the inductor L3 and the ground terminal to completely prevent the voltage passing through the inductor L3 from being applied to the common node A.

Next, the operation of the output matching device of the transmitting end of the mobile communication terminal according to another embodiment of the present invention will be described.

When the battery voltage Vbat is applied to the voltage supply circuit 200 through the filter 100, since the voltage of the common node A becomes R2 / (R1 + R2) * Vbat, the smaller the Vbat, the more common node. The voltage of (A) becomes small.

When the voltage of the common node A is applied to the varactor diode D1, the charge capacity of the varactor diode D1 varies according to the voltage of the common node A. FIG. That is, when the battery voltage is high and the voltage of the common node A is high, the charge capacity of the varactor diode D1 is decreased, and as the battery voltage is lowered, the voltage of the common node A is lowered and the varactor diode D1 is lowered. ) Will increase the charge capacity. The relationship between the amount of change in the voltage of the common node A and the charge capacity of the varactor diode D1 is shown in FIG. 6.

Due to the change in the charge capacity of the converter diode D1 described above, when the battery voltage is large, the output impedance becomes Zout1, and as the battery voltage decreases, the output impedance moves to the Zout2 side along the admittance circle. See FIG. 7)

Therefore, in the output terminal matching device of the mobile communication terminal transmitting terminal according to another embodiment of the present invention, the output generated by the varactor diode D, the capacitor C2, and the inductor L1 in accordance with the battery voltage Vbat. By determining the impedance Zout, the PAM 10 can maximize the efficiency characteristics and the adjacent channel power saving characteristics.

As described above, according to the output terminal matching device of the mobile communication terminal according to the embodiment of the present invention, when the battery voltage of the mobile communication terminal is high, the adjacent channel power saving (ACPR) characteristic of the PAM is good, so that the efficiency characteristic is low. The output impedance can be adjusted to be higher and the output impedance can be adjusted to improve the adjacent channel power suppression (ACPR) characteristics of the PAM when the battery voltage is lowered.

Therefore, the present invention has an effect that an improved performance can be obtained by designing an output terminal matching device of a mobile communication terminal transmitting terminal so as to satisfy both efficiency characteristics and ACPR characteristics at high voltage and low voltage of a battery. have.

On the other hand, the present invention is not limited to the above-described embodiment, but can be modified and modified within the scope not departing from the gist of the present invention, such modifications and changes should be regarded as belonging to the following claims. will be.

Claims (11)

In the output terminal matching device of the mobile communication terminal transmitting terminal having a voltage amplifier module (PAM) for adjusting the input signal to a predetermined gain characteristic, An output stage matching circuit connected to an output terminal of the PAM to generate an output impedance in accordance with a battery voltage; An output impedance adjuster for adjusting the output impedance based on the battery voltage; And A reverse flow connected between an output terminal of the PAM and an output terminal of the output impedance adjusting unit, applying a voltage output from the output impedance adjusting unit to the output terminal matching circuit, and blocking a reverse flow of the output voltage of the PAM to the output impedance adjusting unit; An output terminal matching device of a mobile communication terminal transmitting end, characterized in that it comprises a blocking unit. The circuit of claim 1, wherein the output stage matching circuit comprises: An inductor connected to an output terminal of the PAM; A variable capacitor having one side connected to an output terminal of the PAM and an input terminal of the inductor and the other side thereof connected to a ground terminal; And a capacitor connected between the output terminal of the inductor and the ground terminal. The method of claim 1, wherein the output impedance adjusting unit A controller which measures the battery voltage and outputs a voltage adjustment signal corresponding to the measured battery voltage; And And a power supply unit for outputting a predetermined voltage corresponding to the voltage adjustment signal and applying the voltage to the output terminal matching circuit via the countercurrent blocking circuit. The method of claim 3, wherein the control unit And a table storing voltage adjustment signals corresponding to respective battery voltages. The method of claim 3, wherein the power supply unit And a digital analog converter (DAC) for outputting a predetermined voltage in analog form corresponding to a digital voltage adjustment signal applied from the control unit. The method of claim 1, wherein the output impedance adjusting unit A filter for removing the ripple component from the battery voltage; And a power supply unit for outputting a predetermined voltage for adjusting the output impedance based on the battery voltage applied through the filter. The method of claim 6, wherein the power supply unit A first resistor and a second resistor configured in series with the filter, And a voltage for adjusting the output impedance from a common node of the first resistor and the second resistor is output. The method of claim 2, wherein the variable capacitor And a capacitor capacity varies according to a voltage of the output terminal of the PAM. The method of claim 2 or 3, wherein the variable capacitor is An output terminal matching device of a transmitter of a mobile communication terminal, characterized in that it is a varactor diode. The method of claim 1, wherein the backflow blocking unit And an output terminal matching device of a transmitter of a mobile communication terminal, said inductor being connected between an output terminal of said PAM and said output impedance adjusting unit. The method of claim 10, wherein the backflow blocking unit One end is connected to the common node of the inductor and the output impedance, the other end of the output terminal matching device, characterized in that it comprises a capacitor connected to the ground terminal.

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