KR20100070670A - Apparatus and method for controlling bias of a power amplifier - Google Patents

Abstract

PURPOSE: An apparatus and a method for controlling the bias of a power amplifier are provided to economically enhance the efficiency of a bias modulator by forming a linear amplifier with a few elements. CONSTITUTION: A first controller(210) generates a first controlling signal in the event a first current amount of a first current output from a switching regulator is lower than an envelope current amount, which corresponds to an input envelope signal. A current supplying unit(216) outputs a second current with a second current amount, which is the current amount resulting from the subtraction of the first current amount from the envelope current amount. A second controller(220) generates a second controlling signal in the event the first current amount exceeds the envelope current amount. A current eliminating unit(226), according to the second controlling signal, eliminates a third current with a third current amount, which is the current amount resulting from the subtraction of the envelope current amount from the first current amount, from the first current. A power amplifier is connected to the output of the switching regulator and a bias controlling device.

Description

Bias control apparatus and method of power amplifier {APPARATUS AND METHOD FOR CONTROLLING BIAS OF A POWER AMPLIFIER}

The present invention relates to a bias control apparatus and method for a power amplifier.

In general, a signal transmission device in a communication system includes a power amplifier, and the signal transmission device amplifies and transmits a signal to be transmitted through the power amplifier.

Meanwhile, in the current communication system, the complexity of the signal is increased due to the large capacity of the multimedia service and the usage data, and the use of the broadband signal is increasing. Accordingly, the power amplifier provided in the signal transmission device requires higher linearity and higher efficiency than before.

Envelope Elimination and Restoration (EER) method and Envelope Tracking (ET: Envelope Tracking, ET) will be referred to as the power amplification method used in the power amplifier. And the like.

When the EER method is used, a saturation amplifier is used as the power amplifier, and when the ET method is used, a linear amplifier is used as the power amplifier. Except for this difference, the EER scheme and the ET scheme are identical in that the power of the power amplifier is provided in the same manner from the bias modulator. That is, when the EER method or the ET method is used, the power amplifier receives power corresponding to an envelope signal from a bias modulator.

Hereinafter, a structure of a signal transmission apparatus used in a conventional communication system will be described in detail with reference to FIG. 1.

1 is a view showing the structure of a signal transmission apparatus used in a conventional communication system.

Referring to FIG. 1, the apparatus for transmitting a signal includes a baseband signal generator 100, a baseband signal controller 102, a bias modulator 104, a high frequency modulator 106, and a power amplifier. 108.

When the baseband signal generator 100 receives a signal such as a voice signal or data, the baseband signal generator 100 generates the input signal as an in-phase (I) signal and a quadrature (Q) signal and outputs the signal to the baseband signal controller 104. do.

The baseband signal controller 102 outputs an envelope signal and a baseband signal using an in-phase signal and a quadrature signal output from the baseband signal generator 100.

The high frequency modulator 106 modulates the baseband signal output from the baseband signal controller 102 into a radio frequency (RF) signal.

The power amplifier 108 receives a signal modulated by the high frequency modulator 106 into a radio frequency signal and amplifies the power of the received signal. The power of the power amplifier 108 is determined by the current and voltage output from the bias modulator 106.

The bias modulator 104 outputs current and voltage to the power amplifier 108. The bias modulator 104 includes a pulse width modulation (PWM) signal generator 110, a switching regulator 112, and a linear amplifier 114. The PWM signal generator 110 converts an envelope signal output from the baseband signal controller 104 into a PWM signal, and outputs the converted PWM signal to the switching regulator 112. The switching regulator 112 outputs a large current to the power amplifier 108 in accordance with the output PWM signal. The linear amplifier 114 outputs a voltage and a linear current to the power amplifier 108 using an envelope signal.

In general, the current output from the switching regulator 112 has a large proportion in the current output from the bias modulator 106 to the power amplifier 108 when compared with the current output from the linear amplifier 114. Occupies. Accordingly, in the bias modulator, the efficiency of the switching regulator 112 is important in the current output operation to the power amplifier 108. In addition, since the linear amplifier 114 supplies a voltage corresponding to the magnitude of the envelope signal to the power amplifier 108, the magnitude range of the output current amount is important.

Equation 1 shows the efficiency of the bias modulator 106 using the efficiency of the switching regulator 112 and the efficiency of the linear amplifier 114.

은 상기 바이어스 변조기(104)의 효율을 나타내고,

은 상기 바이어스 변조기(104)의 출력 전력을 나타낸다. 그리고,

는 상기 스위칭 레귤레이터(112)의 효율을 나타내고,

는 상기 선형 증폭기(114)의 효율을 나타낸다. 또한,

는 상기 바이어스 변조기(104)의 출력에서 상기 스위칭 레귤레이터(112)의 출력이 차지하는 비율을 나타내고,

는 상기 바이어스 변조기(104)의 출력에서 상기 선형 증폭기(114)의 출력이 차지하는 비율을 나타낸다.In Equation 1

Represents the efficiency of the bias modulator 104,

Represents the output power of the bias modulator 104. And,

Denotes the efficiency of the switching regulator 112,

Denotes the efficiency of the linear amplifier 114. Also,

Denotes the ratio of the output of the switching regulator 112 to the output of the bias modulator 104,

Denotes the ratio of the output of the linear amplifier 114 to the output of the bias modulator 104.

이 100W이고, 상기

는 80% 이고, 상기

는 20%인 경우를 예로 들어 설명한다.Referring to Equation 1, the efficiency of the bias modulator 104 is affected by the efficiency of the switching regulator 112. However, when the efficiency of the switching regulator 112 is maximized, the efficiency of the linear amplifier 114 must be increased to increase the efficiency of the bias modulator 104. In order to facilitate this understanding,

Is 100W and above

Is 80%, said

Explain that 20% is taken as an example.

가 95%이고, 상기

가 50%라면, 상기

은 80.5%가 된다. 여기서 상기

는 100%에 가깝기 때문에 상기

을 추가적으로 높이기 위해서는 상기

가 증가되어야 한다. 이에 따라 상기

가 50%에서 70%로 증가될 경우, 상기

은 80.5%에서 88.7%로 증가된다. In the above cases

Is 95% and said

Is 50%, the above

Becomes 80.5%. Where above

Recall because is close to 100%

To further increase

Should be increased. Accordingly

If is increased from 50% to 70%,

Increases from 80.5% to 88.7%.

On the other hand, the efficiency of the linear amplifier 114 refers to the power consumed in the linear amplifier 114, which is also related to the size range of the output current amount of the linear amplifier 114. In general, a high power device has a narrow size range of the output current amount, and a low power device has a wide size range of the output current amount. When the power consumption of one device in the linear amplifier 114 cannot be accommodated, several devices may be arranged in parallel. In this case, the size range of the amount of output current is also affected by the number of devices arranged.

The present invention proposes a bias control apparatus and method for a power amplifier for improving the efficiency of the bias modulator.

In addition, the present invention proposes a bias control apparatus and method for a power amplifier for minimizing the elements constituting the linear amplifier to widen the range of the amount of output current of the linear amplifier, and improve the efficiency of the bias modulator.

The device proposed in the present invention; A bias control apparatus for a power amplifier, comprising: a first controller configured to generate a first control signal when a first current amount of a first current output from a switching regulator is less than an envelope current amount corresponding to an input envelope signal; and the first control signal And a current supply unit for outputting a second current having a second current amount which is a current amount obtained by subtracting the first current amount from the envelope current amount, and generating a second control signal when the first current amount exceeds the envelope current amount. And a second control unit and a current removing unit for removing a third current having a third current amount, which is a current amount obtained by subtracting the envelope current amount from the first current amount, from the first current according to the second control signal.

The method proposed in the present invention; Generating a first control signal when the first current amount of the first current output from the switching regulator is less than the envelope current amount corresponding to the input envelope signal; and according to the first control signal, the first current amount in the envelope current amount Outputting a second current having a second current amount which is an amount of current minus the second; generating a second control signal when the first current amount exceeds the envelope current amount; and according to the second control signal, And removing a third current having a third current amount which is a current amount obtained by subtracting the envelope current amount from one current amount, from the first current.

The present invention can adjust the amount of current output from the switching regulator through a linear amplifier, not only can increase the efficiency of the bias modulator, but also has the advantage of maintaining a constant amount of power output to the power amplifier. In addition, the present invention has the advantage that the configuration of the linear amplifier with a small number of elements to widen the size range of the output current amount of the linear amplifier and to improve the efficiency of the bias modulator more economically.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

2 illustrates a structure of a bias modulator according to an exemplary embodiment of the present invention.

2 will be described with reference to the switching regulator 200 and the linear amplifier 202 included in the bias modulator according to an embodiment of the present invention. In the following description, for the sake of clarity, the current output from the switching regulator 200 and the linear amplifier 202 of FIG. 2 according to an exemplary embodiment of the present invention will be described with reference to FIG. 3.

The switching regulator 200 outputs a low frequency current as a current source. According to an embodiment of the present invention, the switching regulator 200 may be configured as a low speed switching regulator. The current output from the switching regulator 200 (hereinafter referred to as 'switching current') is the same as the portion indicated by the blue line in FIG. In addition, the switching current occupies a large proportion of the current output to the power amplifier as compared with the current output from the linear amplifier 202. Therefore, the power of the power amplifier is greatly affected by the amount of the switching current (hereinafter referred to as 'switching current amount').

The bias modulator includes a current corresponding to an envelope signal, which is a signal input to the bias modulator (hereinafter, referred to as 'envelope current') as shown by the red line portion of FIG. 3 (a), to the power amplifier. The final output should be. Accordingly, in the embodiment of the present invention, in order to output the current corresponding to the blue line portion of FIG. 3 (a) as the current corresponding to the red line portion of FIG. 3 (a), the linear amplifier 202 is The present invention provides a method of removing excess current from the switching current or supplying current less than the switching current.

The linear amplifier 202 may include a first control unit 210, a power supply unit 211, a high-side current supply unit 212, a first high speed switching unit 214, and a main current supply unit 216. ), A second control unit 220, a ground unit 221, a low-side current removing unit 222, a second high speed switching unit 224, and a main current removing unit 226.

When the envelope signal is input as the voltage source, the main current supply unit 216 and the main current remover 226 output a voltage corresponding to the envelope signal.

When the switching current amount is less than the amount of envelope current (hereinafter referred to as 'envelope current amount') at any one of a predetermined periodic time point, the main current supply unit 216 selects a current amount that is less than that. To receive from the upper current supply unit 212 and the first high-speed switching unit 214 the current of the less than the current amount (hereinafter referred to as "less current"), and outputs the received less current do. The undercurrent output from the main current supply unit 216 is output to the power amplifier together with the switching current. Here, the current output to the power amplifier corresponds to the envelope current.

On the contrary, the main current removing unit 226 at the time of any one of the predetermined periodic time, when the amount of the switching current exceeds the amount of the envelope current, the current by the amount of excess current (hereinafter 'over' Current ') is output to the lower current removing unit 222 and the second high speed switching unit 224. Then, the excess current output from the main current removing unit 226 is removed through the lower current removing unit 222 and the second high speed switching unit 224. Accordingly, the switching current from which the excess current is removed is output to the power amplifier, and as a result, the power amplifier receives a current corresponding to the envelope current.

Meanwhile, according to an exemplary embodiment of the present invention, the amount of less current supplied through the main current supply unit 216 and the amount of excess current removed through the main current removal unit 226 are determined by the following equations (2) and (3).

In Equation 2, I represents the amount of current required in the power amplifier, and V represents the voltage output from the linear amplifier 202. And R represents a resistance in the power amplifier that is determined to correspond to the envelope signal.

The amount of current required by the power amplifier is calculated as in Equation 2, but the amount of current output from the bias modulator to the power amplifier is substantially as shown in Equation 3 below.

In Equation 3, I represents the amount of current output from the bias modulator to the power amplifier. And I 'represents the amount of current output from the linear amplifier 202, I "represents the amount of switching current. In general, since the switching regulator 200 outputs a current having a lower frequency than the linear amplifier 202, the switching regulator 200 responds slowly to the change in the envelope signal. Accordingly, when the switching current is output slowly such as the blue line of FIG. 3 (a), the amount of current to be added or removed in the linear amplifier 202 is determined. Then, when the linear amplifier 202 further needs to output current according to the determined amount of current, the first control unit 210, the upper current supply unit 212, the first high speed switching unit 214, and the The main current supply unit 216 operates, and in the opposite case, the second control unit 220, the lower current remover 222, the second high speed switching unit 224, and the main current remover 226. Will work.

FIG. 3B is a graph showing the undercurrent supplied from the main current supply unit 216 and the excess current removed through the main current removal unit 226 according to an embodiment of the present invention. That is, in FIG. 3B, a red line representing an amount of current greater than or equal to zero represents a current less than a current output from the main current supply unit 216, and a blue line representing an amount of current equal to or less than zero represents the main current removal portion ( Excess current removed via 226).

The main current supply unit 216 receives the less current from the upper current supply unit 212 and the first high speed switching unit 214. Referring to FIG. 3 (c), the red line in FIG. 3 (c) represents the less current output from the main current supply unit 216. The less current output from the main current supply unit 216 is provided from the upper current supply unit 212 and the first high speed switching unit 214.

Specifically, when less current is to be output from the linear amplifier 202, the upper current supply unit 212 receives a current output from the power supply unit 211 and uses the supplied current. To generate current. According to an embodiment of the present disclosure, the upper current supply unit 212 starts operation before the first high speed switching unit 214. Specifically, after the current corresponding to a predetermined reference current amount is generated in the upper current supply unit 212 at the initial time of the current supply process, the operation of the first high speed switching unit 214 is started.

Accordingly, the first control unit 210 detects a current existing between the power supply unit 211 and the upper current supply unit 212 at an initial time point when the operation of the upper current supply unit 212 starts, and the detected It is determined whether the amount of current exceeds a predetermined first reference current amount.

According to an embodiment of the present invention, the first controller 210 may be a comparator, an operational amplifier, a gate driver, or the like. The first reference current amount is used as a reference to perform an operation for generating substantially less current in the first fast switching unit 214 and the upper current supply unit 212. Accordingly, when the amount of the sensed current exceeds the first reference current amount, the first control unit 210 generates a first control signal and outputs the first control signal to the first high speed switching unit 214. The first control signal is a control signal for operating the first high speed switching unit 214 and may be, for example, a pulse width modulation signal.

The first high speed switching unit 214 generates a current having a current amount indicated by a blue line in FIG. 3 (c) according to the received first control signal (hereinafter referred to as 'first supply current'). . According to an embodiment of the present invention, since the first high speed switching unit 214 can operate with only relatively little power, the first high speed switching unit 214 is a relatively low power high speed switch, a diode, and a relatively low inductor. It is possible to implement.

 The upper current supply unit 212 is a current having a current amount obtained by subtracting the current amount of the first supply current from the difference of the current amount between the red line and the blue line in FIG. Supply current ').

Meanwhile, according to an exemplary embodiment of the present invention, the first and second supply currents may be generated using a current existing between the power supply unit 211 and the upper current supply unit 212.

The main current remover 226 removes excess current through the lower current remover 222 and the second high speed switch 224. Referring to FIG. 3 (d), the red line of FIG. 3 (d) is the excess current removed through the main current removing unit 226, that is, the lower current removing unit 222 and the second high speed switching. Excess current removed at section 224 is indicated.

In detail, when the switching current amount exceeds the envelope current amount in the linear amplifier 202, the main current remover 226 transmits the excess current to the lower current remover 222 and the first current. 2 is output to the high speed switching unit 224. The excess current is then removed through the lower current remover 222 and the second high speed switch 224.

 According to an embodiment of the present disclosure, the lower current remover 222 starts to operate before the second high speed switch 224. Specifically, the second high speed switching unit 224 starts after the current corresponding to the predetermined reference current amount is removed from the lower current removing unit 222 at the initial time of the current removing process.

Accordingly, the second controller 220 detects a current existing between the ground unit 221 and the lower current remover 222 at an initial time point when the operation of the lower current remover 222 starts. It is determined whether the detected amount of current exceeds a preset second reference current amount.

According to an exemplary embodiment of the present invention, the second controller 220 may be a comparator, an operational amplifier, a gate driver, or the like like the first controller 210. The second reference current amount is used as a reference to perform an operation for substantially removing excess current in the second high speed switching unit 224 and the lower current removing unit 222. Accordingly, when the amount of the sensed current exceeds the second reference current amount, the second control unit 220 generates a second control signal and outputs the second control signal to the second high speed switching unit 224. Here, the second control signal is a control signal for operating the second high speed switching unit 224, and may be, for example, a pulse width modulation signal.

The second high speed switching unit 224 removes a current having a current amount indicated by a blue line in FIG. 3 (d) according to the received second control signal (hereinafter referred to as 'first removal current'). . According to the exemplary embodiment of the present invention, the second high speed switching unit 224 may operate with relatively low power, similar to the first high speed switching unit 214 described above. It can be implemented as an inductor, etc.

The lower current removing unit 222 is a current having a current amount obtained by subtracting the current amount of the first removing current from the difference between the current amounts between the red and blue lines of FIG. 3 (d), that is, the excess current. Second removal current ').

As such, the present invention can adjust the amount of the switching current to correspond to the amount of the envelope current in the linear amplifier 202 configured as described above, there is an advantage that the power of the power amplifier can be made constant according to the envelope current have.

Now, referring to FIGS. 4A and 4B, which are flowcharts showing the operation of the linear amplifier 202 according to an embodiment of the present invention, the operation of the linear amplifier 202 configured as shown in FIG. 2 is described. Explain.

First, in FIG. 4A, when the amount of switching current of FIG. 2 is less than the envelope current amount, the linear amplifier 202 provides a case where the amount of the less current is provided.

In operation 400, the first controller 210 determines whether a current is detected, and proceeds to operation 402 when the current is detected. The detected current is a current existing between the power supply unit 211 and the upper current supply unit 212, and may be periodically detected by the first control unit 210.

According to an exemplary embodiment of the present invention, the first high speed switching unit 214 operates after the current generated by the preset reference current amount is generated by the upper current supply unit 212 at the initial point of the current supply process. Accordingly, the first controller 210 determines whether the amount of the sensed current exceeds a predetermined amount of the first reference current in step 402. The first controller 210 proceeds to step 404 when the amount of the sensed current exceeds the amount of the first reference current. The first control unit 210 generates a first control signal for generating a current to be supplied in step 404, and outputs the generated first control signal to the first high speed switching unit 214.

The first high speed switching unit 214 that has received the first control signal generates a first supply current according to the generated first control signal in step 406. In operation 408, the upper current supply unit 212 generates the second supply current using the lower current and the first supply current. In detail, the upper current supply unit 212 generates the second supply current having a current amount obtained by subtracting the first supply current amount from the less current amount.

The first supply current and the second supply current generated as described above are output to the main current supply unit 216. In operation 410, the main current supply unit 216 outputs the first supply current and the second supply current. The current output from the main current supply unit 216 is output to the power amplifier together with the switching current. Accordingly, the power amplifier can receive a current corresponding to the envelope current.

Next, referring to FIG. 4B, when the switching current amount exceeds the envelope current amount, the case where the excess current amount is removed by the linear amplifier 202 will be described.

When the switching current amount exceeds the envelope current amount in step 420, the main current removing unit 226 outputs an excess current having a current amount equal to the excess current amount.

Then, the second controller 220 determines whether a current is detected in step 422, and proceeds to step 424 when the current is detected. The sensed current is a current existing between the lower current remover 222 and the ground 221 and may be periodically detected.

According to the exemplary embodiment of the present invention, the second high speed switching unit 224 operates after the current corresponding to a predetermined reference current amount is removed from the lower current removing unit 222 at the initial time of the current removing process. Accordingly, when it is determined in step 424 that the amount of the sensed current exceeds the amount of the second reference current, the second controller 220 proceeds to step 426 to provide a second control signal for removing excess current. Create The current removal controller 220 outputs the generated second control signal to the second high speed switching unit 224.

In operation 428, the second fast switching unit 224 receiving the second control signal removes the first removal current according to the second control signal. In operation 430, the upper current removing unit 222 removes the second removing current using the excess current and the first removing current. In detail, the upper current removing unit 222 removes the second removing current having a current amount obtained by subtracting the current amount of the first removing current from the current amount of the excess current.

When the first elimination current and the second elimination current are removed from the current output from the switching regulator 200 as described above, the power amplifier can receive the current corresponding to the envelope signal.

As described above, since the switching current amount can be adjusted by the linear amplifier 202, the efficiency of the bias modulator can be increased and the amount of current output to the power amplifier can be kept constant.

In the above-described embodiment, the case where the high speed switching unit, that is, the first and second high speed switching units 214 and 224 are used in the linear amplifier 202 has been described.

When a lower speed switching unit (hereinafter referred to as a "middle speed switching unit") is used than the high speed switching unit, a less current generation rate or an excess current removal rate is slower than when the high speed switching unit is used. The amount of power consumed in the linear amplifier 202 is relatively increased.

 In addition, when the medium speed switching unit is used, it becomes difficult to add the undercurrent to the switching current or to remove the excess current from the switching current. This is because the undercurrent generation rate or excess current removal rate in the medium speed switching unit is slower than the undercurrent generation rate or excess current removal rate in the high speed switching unit. Specifically, the waveform of the undercurrent and the excess current in the medium speed switching unit is wider than the waveform of the undercurrent and excess current in the high speed switching unit. Therefore, it is difficult to adjust the amount of current of the switching current in the medium speed switching unit.

Accordingly, in another embodiment of the present invention, when the intermediate amplifier is provided with the medium speed switching unit, the current removing process may be performed even when an additional current is to be provided to the switching current, and the current supply process may be performed even when the ammeter is to be removed. We propose a method of adjusting the switching current amount by performing. For a detailed description thereof, a structure of a bias modulator according to another embodiment of the present invention will be described below with reference to FIG. 5.

The switching regulator 500 shown in FIG. 5 is the same as the switching regulator 200 of FIG. In addition, the components of the linear amplifier 502 shown in FIG. Except for the configuration of the linear amplifier 202 of FIG. Therefore, in the following description, the description of the same components as the switching regulator 200 and the linear amplifier 202 of FIG. 2 will be omitted.

The first intermediate speed switching unit 514 illustrated in FIG. 5 generates a first supply current according to the first control signal of the first control unit 510. The first intermediate speed switching unit 514 has a lower current generation rate than the first high speed switching unit 214 of FIG. 2. Therefore, the waveform of the third supply current output from the first intermediate speed switching unit 514 is wider than the waveform of the first supply current output from the first high speed switching unit 514. That is, there is a current to be added or removed in the third supply current. Accordingly, in the embodiment of the present invention, the upper current supply unit 511 performs current removal in addition to the current supply in order to correspond the third supply current to the less than the current to be finally output from the main current supply unit 516.

In order to help understand this, it will be described with reference to Figure 6a showing a third supply current and a less than the current according to an embodiment of the present invention. As shown in FIG. 6A, the waveform of the third supply current 608 does not correspond to the waveform of the undercurrent 600. Accordingly, when the lower current amount is less than the current amount of the third supply current, the upper current supply unit 511 outputs a current having the current amount minus the current amount of the third supply current.

The upper current removing unit 512 removes a current having a current amount obtained by subtracting the amount of the current less than the amount of the third supply current from the third supply current when the amount of the current under the current exceeds the third supply current.

Accordingly, since the third supply current 608 is adjusted to correspond to the undercurrent 600 and is output to the main current supply unit 516, the present invention can control the output to the power amplifier even when the medium speed switching unit is used. There is an advantage to that.

Meanwhile, the current removing process when the medium speed switching unit is used will be described below. When the excess current is output from the main current removing unit 526, the second intermediate speed switching unit 524 removes the third removing current having a current amount smaller than the excess current amount.

The third removal current is generated according to a control signal of the second controller 520. The second intermediate speed switching unit 524 is lower in speed than the second high speed switching unit 224. Therefore, in another embodiment of the present invention, the current supply is further performed along with the current removal to make the third removal current correspond to the excess current.

For clarity, the third removal current and the excess current according to the exemplary embodiment of the present invention will be described with reference to FIG. 6B. Referring to FIG. 6B, in order to correspond the third removal current 618 to the excess current 610, the lower current removal unit 522 may include the third current when the excess current amount is less than the third removal current amount. A current having a current amount obtained by subtracting the excess current amount from the removal current amount is output.

The lower current supply unit 521 removes a current having a current amount obtained by subtracting the third removal current amount from the excess current amount when the excess current amount exceeds the third removal current amount.

 Accordingly, the present invention has an advantage of more precisely controlling the output of the bias modulator through the linear amplifier 502 configured as described above even if the medium speed switching unit is used.

On the other hand, in the above-described embodiment of the present invention has been described a case where the switching current amount is greater than or less than the envelope current amount. However, when the switching current amount is equal to the envelope current amount, the under current providing operation and the excess current removing operation in the linear amplifier are not performed. That is, the switching current becomes the final output current of the bias modulator.

 In the embodiment of the present invention, the component for providing the undercurrent and the component for removing the excess current are divided, but the current output and the current removing operation may be performed in one component.

In addition, according to an embodiment of the present invention, any one of the components for providing the under-current and the component for removing the excess current may be omitted.

1 is a view showing the structure of a signal transmission apparatus used in a conventional communication system,

2 is a view showing the structure of a bias modulator according to an embodiment of the present invention;

3 is a diagram illustrating a current output from the switching regulator 200 and the linear amplifier 202 of FIG. 2 according to an embodiment of the present invention;

4A and 4B are flowcharts illustrating an operation process of the linear amplifier 202 according to an embodiment of the present invention.

5 illustrates a structure of a bias modulator according to another embodiment of the present invention;

Figure 6a is a view showing a third supply current and a less than current according to an embodiment of the present invention,

6B is a view illustrating a third removal current and an excess current according to an embodiment of the present invention.

Claims (12)

In the bias control device of the power amplifier, A first controller configured to generate a first control signal when the first current amount of the first current output from the switching regulator is less than the envelope current amount corresponding to the input envelope signal; A current supply unit outputting a second current having a second current amount which is a current amount obtained by subtracting the first current amount from the envelope current amount according to the first control signal; A second controller configured to generate a second control signal when the first current amount exceeds the envelope current amount; And a current removing unit for removing a third current having a third current amount, which is a current amount obtained by subtracting the envelope current amount from the first current amount, from the first current according to the second control signal. The method of claim 1, A power amplifier that amplifies a radio frequency signal using an input current is connected to the bias control device and the output of the switching regulator, Wherein the input current is one of a current having an amount of current corresponding to a current obtained by subtracting the first current from the second current and the first current, and the third current. . The method of claim 1, The current supply unit, A first high speed switching unit outputting a first supply current having a current amount less than the second current amount according to a control signal of the first control unit; A high side current supply unit configured to output a second supply current having a current amount obtained by subtracting the current amount of the first supply current from the second current amount; And a main current supply unit configured to receive the first supply current and the second supply current, and output the second current including the received first supply current and the second supply current. The method of claim 1, The current removing unit, A main current removing unit for outputting the third current; A second high speed switching unit for removing a first removal current having a current amount less than the third current amount from the third current according to a control signal of the second control unit; And a low side current removal unit configured to remove a second removal current having a current amount obtained by subtracting the current amount of the first removal current from the third current amount. The method of claim 1, The current supply unit, A first middle speed switching unit outputting a third supply current having a current amount less than the second current amount according to the first control signal; An upper current supply unit configured to output a fourth current having a current amount obtained by subtracting the current amount of the third supply current from the second current amount when the second current amount is less than the current amount of the third supply current; An upper current removing unit removing a fifth current having a current amount obtained by subtracting the second current amount from the third supply current amount when the second current amount exceeds the third supply current amount; And a main current supply unit configured to output the third supply current from which the fourth current is added through the upper current remover and the fifth current is removed through the upper current remover. Device. The method of claim 1, The current removing unit, A main current removing unit for outputting the third current; A second intermediate speed switching unit configured to remove a third removal current having a third removal current amount less than the third current amount in the third current; A lower current supply unit for outputting a current having a current amount obtained by subtracting the third current amount from the third removal current amount when the third current amount is less than the third removal current amount; And a lower current removing unit for removing a current having a current amount obtained by subtracting the third removal current amount from the third current amount when the third current amount exceeds the third removal current amount. In the bias control method of the power amplifier, Generating a first control signal when the first current amount of the first current output from the switching regulator is less than the envelope current amount corresponding to the input envelope signal; Outputting, according to the first control signal, a second current having a second current amount which is a current amount obtained by subtracting the first current amount from the envelope current amount; Generating a second control signal when the first current amount exceeds the envelope current amount; And removing, according to the second control signal, a third current having a third current amount which is a current amount obtained by subtracting the envelope current amount from the first current amount from the first current. The method of claim 7, wherein A power amplifier connected to the bias control device and the output of the switching regulator further comprises amplifying a radio frequency signal using an input current, The input current is a bias control method of a power amplifier, characterized in that the current having a current amount corresponding to the current of the second current and the first current is added and the third current minus the first current. The method of claim 7, wherein The process of outputting the second current, Outputting a first supply current having a current amount less than the second current amount according to a control signal of the first controller; Outputting a second supply current having a current amount obtained by subtracting the current amount of the first supply current from the second current amount; Receiving the first supply current and the second supply current, and outputting the second current including the received first supply current and the second supply current. The method of claim 7, wherein Removing the third current from the first current, Outputting the third current; Removing a first removing current having a current amount less than the third current amount from the third current according to a control signal of the second controller; And removing a second removal current having a current amount obtained by subtracting the current amount of the first removal current from the third current amount. The method of claim 7, wherein The process of outputting the second current, Outputting a third supply current having a current amount less than the second current amount according to the first control signal; Outputting a fourth current having a current amount obtained by subtracting the current amount of the third supply current from the second current amount when the second current amount is less than the current amount of the third supply current; Removing a fifth current having a current amount obtained by subtracting the second current amount from the third supply current amount from the third supply current when the second current amount exceeds the third supply current amount; And outputting the third supply current from which the fourth current is added through the upper current supply unit and the fifth current is removed through the upper current removal unit. The method of claim 7, wherein Removing the third current from the first current, Outputting the third current; Removing a third removal current having a third removal current amount less than the third current amount from the third current; Outputting a current having a current amount obtained by subtracting the third current amount from the third removal current amount when the third current amount is less than the third removal current amount; And removing the current having a current amount obtained by subtracting the third removal current amount from the third current amount when the third current amount exceeds the third removal current amount.

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