KR20090036965A - Method and apparatus for controlling the power of a power amplifier - Google Patents

Abstract

A method and an apparatus for controlling the power of a power amplifier are provided to perform power control of the fixed point operation mode by using a microcontroller. An attenuator outputs an attenuation signal by attenuating an input signal according to the power control signal. A power amplifier(160) amplifies an attenuation signal and outputs an amplification signal. A first sensor(121) measures the power of the input signal and calculates a first power value. A second sensor(122) measures the power of an amplification signal and calculates a second power value. A power controller(135) generates a power control signal based on a first power value and a second power value. A second sensing unit measures the power of the amplification signal and calculates the second power value. The power control unit includes a first controller, a second controller, and a power control signal generator. The power control signal generator generates the power control signal by using a first moving average and a second moving average.

Description

TECHNICAL AND APPARATUS FOR CONTROLLING THE POWER OF A POWER AMPLIFIER

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a power control method of a power amplifier (PA), and more particularly, to a method and an apparatus for controlling power of a power amplifier using a fixed-point arithmetic microcontroller.

The power amplifier (hereinafter referred to as "PA") is an apparatus for amplifying the power of a signal input through an input terminal at a predetermined magnification and providing the same to an output terminal. In particular, the PA is used to amplify the RF signal before transmitting it to the base station, and amplifying and providing the RF signal with high efficiency without distortion is one of the very important technical goals in a small communication device such as a mobile communication terminal. For this purpose, various PA power control technologies such as ALC (Automatic Level Control) and AGC (Automatic Gain Control), which control the power of a signal input to the PA by measuring the power of the input / output signal of the PA, are known.

In order to perform such PA power control, a conventional PA uses an analog device. In detail, the analog PM (Power Monitoring) device measures the power of the input and output signals of the PA, respectively, and outputs a voltage signal corresponding thereto, and the analog power control device outputs the power of the PA according to the voltage signal generated by the PM device. Perform control. However, when a signal whose amplitude or power rapidly fluctuates, such as a burst signal, or a very loud noise signal is input to the PA, the power control device does not effectively perform a power control operation. Accordingly, there is a problem that the operation of the PA becomes unstable.

As a method of effectively coping with such an input burst signal or a noise signal, preprocessing, for example, moving average (MA) processing is performed on a voltage signal output from a PM device to reduce the influence of a burst signal or a noise signal. Known methods are known. The MA process calculates an average value of the voltage signals located in each window while moving a window having a predetermined size along the voltage signal, and outputs the average value signal. . However, there are many technical difficulties in implementing such an MA processing operation in an analog power control device.

Specifically, the PM device generally measures the power of the signal input to the PA in log units, for example, in dBm, and thus, the voltage signal input to the power control device corresponds to the power value in dBm. However, moving average processing is performed on signals corresponding to power values in linear units, for example Watts. Accordingly, when the power control device receives a voltage signal corresponding to a power value in dBm from the PM device, to perform MA processing on the power signal, the input voltage signal should be converted into a signal in Watt. However, it is expensive to equip the analog device with a circuit for performing the above-described conversion operation and moving average calculation operation.

In order to solve this problem, in the case of using the digital power control device, the floating point method has been conventionally used for the above-described conversion and moving average calculation. This floating point method is a notation for dividing a number into a part (fixed number) representing a fixed point point and a part (exponent) representing a fixed point position, which represents a wider range of numbers than the fixed point method. Compared to the method there is an easy advantage. However, the floating point method requires a larger amount of computation than the fixed point method. Therefore, an expensive processor (for example, a Pentium chip) having a relatively high computational power instead of a low cost microcontroller is required for the digital power controller. There is a problem with using.

An object of the present invention is to provide a method and apparatus for performing power control for a power amplifier using a digital fixed point arithmetic method.

According to an aspect of the present invention, there is provided a power control system including a power amplifier and a power control device for controlling the power of an input signal input to the power amplifier. The power control system includes: an attenuation unit configured to attenuate the input signal according to a power control signal to output attenuation signal; A power amplifier for power amplifying the attenuated signal and outputting an amplified signal; A first sensing unit measuring a power of the input signal and calculating a series of first power values; A second sensing unit measuring a power of the amplified signal and calculating a series of second power values; And a power control unit generating the power control signal based on the series of first and second power values.

The power control unit may include a first converter converting the series of first power values into a series of first dB indices, a first search unit searching for a series of linear indices corresponding to the converted series of dB indices, and the A first control unit including a first moving average value generating unit generating a series of first moving average values MA for a series of linear indices; A second converter for converting the series of second power values into a series of dB indices, a second searcher for searching for a series of linear indices corresponding to the converted series of dB indices, and a series of the series of linear indices A second control unit including a second moving average value generating unit configured to generate a second moving average value MA; And a power control signal generator configured to generate the power control signal using the series of first moving average values and the series of second moving average values.

In an embodiment, the first converter stores a first conversion equation for calculating a series of dB indices corresponding to the series of first power values, and the second converter corresponds to the series of first power values. A second conversion equation for calculating a series of dB indices may be stored. In this case, the first conversion equation may include at least one first conversion constant, and the second conversion equation may include at least one second conversion constant.

In another embodiment, the system may further include a storage unit for storing the first and second conversion constant table. In this case, the first and second conversion constant tables may include at least one first and second power value intervals and first and second conversion constants corresponding to the first and second power value intervals, respectively. .

In another embodiment, the first conversion unit searches for the first conversion constants corresponding to the first power value interval to which each of the first power value belongs in the first conversion constant table for each of the first power value; And substituting the retrieved first conversion constants into the first conversion equation to calculate a dB index corresponding to each of the first power values, and wherein the second conversion unit is configured in the second conversion constant table for each of the second power values. Search for second conversion constants corresponding to a second power value interval to which each second power value belongs, and substitute the retrieved second conversion constants into the second conversion equation to obtain a dB index corresponding to each second power value. Can be calculated

In still another embodiment, the storage unit stores a dB index table including a series of dB indexes and a series of linear indices respectively corresponding to the series of dB indexes, and the first search unit stores the first and second indexes in the dB index table. Search for a series of linear indices corresponding to the series of dB indices converted from one power values, and the second search unit searches for a series of dB indices converted from the second power values in the dB index table You can search for linear indices.

In another embodiment, the first search unit searches for a series of first dB indices corresponding to the series of first moving average values in the dB index table, and the second search unit searches for the series in the dB index table. The series of second dB indices corresponding to the second moving average may be searched, and the power control signal generator may generate the power control signal using the searched first and second dB indices.

According to another aspect of the present invention, a method of generating a conversion constant table for power control is provided. The method includes generating a test signal and inputting it to a power amplifier that outputs an amplified signal in response to the input of the test signal; Branching the amplified signal to provide first and second branch signals; Measuring power of the first branch signal to provide a series of first power values; Measuring the power of the second branch signal to provide a series of second power values; Calculating inflection points of the series of second power values; Determining at least one power value interval using the calculated inflection points; Calculating conversion constants for the determined power value intervals using the series of first and second power values; And storing the determined power value intervals and the calculated conversion constants for the determined power value intervals in correspondence with the conversion constant table, respectively.

In an embodiment, the inputting step may include: measuring a driving current supplied to the power amplifier; And attenuating the test signal according to the measured driving current. In another embodiment, the test signal may be a signal in which the power or magnitude of the corresponding signal monotonically increases with time.

According to another aspect of the present invention, there is provided a method of controlling the power of a signal input to a power amplifier using a conversion constant table generated according to the method described above. The method includes converting a power value of a signal output from the power amplifier into a dB index using the conversion constant table; And controlling the power of the signal input to the power amplifier using the converted dB index.

According to another aspect of the present invention, a method of generating a conversion constant table for power control is provided. The method comprises branching a test signal for a power amplifier to provide first and second branch signals, wherein the first branch signal is input to the power amplifier and the second branch signal is input to a detector of the power amplifier. -; Measuring power of the first branch signal to provide a series of first power values; Measuring the power of the second branch signal to provide a series of second power values; Calculating inflection points of the series of second power values; Determining at least one power value interval using the calculated inflection points; Calculating conversion constants for the determined power value intervals using the series of first and second power values; And storing the determined power value sections and the calculated conversion constants for the determined power value sections in correspondence with the conversion constant table, respectively.

According to another aspect of the present invention, there is provided a method of controlling the power of a signal input to a power amplifier using a conversion constant table generated according to the method described above. The method includes converting a power value of a signal input to the power amplifier into a dB index using the conversion constant table; And controlling the power of the signal input to the power amplifier using the converted dB index.

According to certain embodiments of the present invention, there is an effect that can provide a method and apparatus for performing power control for a power amplifier using a digital fixed-point arithmetic method.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it will be apparent that these embodiments may be practiced without some or all of these details. In other instances, well known procedures or configurations have not been described in detail in order not to unnecessarily obscure the description of the present invention.

1 is a conceptual diagram of a power amplifier (PA) control system according to an embodiment of the present invention. Referring to FIG. 1, the PA control system 100 according to an exemplary embodiment of the present invention may include a first branching unit for branching an input signal into two signals, for example, first and second signals at a predetermined ratio ( 111). The first signal branched from the first branch unit 111 is input to the variable storage unit 150, and the variable resistor unit 150 has a function of attenuating the first signal to the analog power control signal input to the control input. do. The variable resistor unit 150 is coupled with a PA 160 driven by a driving power source Vcc. The PA 160 receives a signal attenuated by the variable resistor unit 150 and amplifies the power at a predetermined magnification. Let's do it. The inspector 180 functions to measure a driving current Icc flowing from the driving power supply Vcc of the PA 160 to the PA 160.

The PA control system 100 further includes a second branch 112. Like the first branch 111, the second branch 112 also receives an input signal, that is, an amplified signal output from the PA 160. It branches to two signals, for example, the third and fourth signals at a predetermined ratio. The third signal output from the second branch 112 is transmitted to the RF output terminal via the isolator 170. The isolator 170 serves to suppress a signal reflected from the RF output terminal 170 toward the second branch 112.

Meanwhile, second and fourth signals output from the first and second branch parts 111 and 112 are input to the first and second detectors 121 and 122, respectively. The power of the second and fourth signals is measured in log units (eg, in dBm) to generate a voltage signal corresponding thereto. The first and second detectors 121 and 122 are connected to the microcontroller 130. The microcontroller 130 functions to generate a digital power control signal for the PA 160 according to voltage signals provided from the first and second sensing units 121 and 122. The PA control system 100 may further include a digital to analog converter (DAC) unit 140 for converting a digital power control signal provided from the microcontroller 130 into an analog power control signal.

In one embodiment, the microcontroller 130 is an analog voltage signal (ie, analog dBm power signal) indicating the input and output power of the PA 160 in dBm unit from each of the first and second detectors 121 and 122, respectively. ), And convert each of them into digital dBm power values, and perform power control operations such as Automatic Level Control (ALC) and Automatic Gain Control (AGC) on the PA 160 using the converted digital dBm power values. do. In this case, before the power control operation is performed using the converted digital dBm power value in the microcontroller 130, predetermined signal processing or preprocessing may be performed on the converted digital dBm power value.

In detail, a signal or a very loud noise whose amplitude or power fluctuates rapidly, such as a burst signal, to a voltage signal (or a digital dBm power value converted into a digital signal) input to the microcontroller 130. If a signal is included and input, the microcontroller 130 may not perform the power control operation effectively, and thus the operation of the PA 160 may become unstable. In order to effectively deal with such a burst signal or a noise signal, the microcontroller 130 performs a signal processing or preprocessing, for example, a MA processing on the digital dBm power value before performing a power control operation to perform a burst signal or noise. The influence by the signal or the like can be reduced.

The MA process is a method of calculating an average value of digital dBm power values located in each window while moving windows of a predetermined size along the series of digital dBm power values, and smoothing the converted series of digital values. To reduce the effects of burst signals, etc. However, in order to perform such MA processing, digital dBm power values in dBm must be converted into power values in linear units, for example, Watt units (that is, digital watt power values). In detail, in order to find the average of 3 dBm (= 2 watts) and 6 dBm (= 4 watts), you cannot simply calculate the mean by simply adding 3 dBm and 6 dBm and then dividing it. After conversion to 2 watts and 4 watts, respectively, add them together to find their average. However, in order to perform such a conversion operation (conversion from a log unit value to a linear unit value) in a digital device, a floating point operation must be performed. There are many technical difficulties to follow.

Accordingly, the microcontroller 130 according to an embodiment of the present invention includes one dB index table including at least one log index (eg, dB index) and a linear index corresponding thereto, and the digital dB The power value is converted into a dB index according to a preset conversion equation, and a linear index corresponding to the converted dB index is searched in the dB index table. Here, the dB index may be an unsigned integer. Since the operation of converting the log unit value (dBm power value / dB index) into the linear unit value (watt power value / linear index) is performed by using the dB index table rather than performing a direct operation, the microcontroller ( 130 may perform the MA processing using a fixed-point arithmetic method, which has much smaller computational throughput than floating-point arithmetic.

In addition, instead of converting the digital dBm power value directly to the wattage power value (or the linear index), an operation of first converting the digital dBm power value to the dB index using a conversion equation is performed. Therefore, when a separate conversion equation is provided for each of the first and second sensing units 121 and 122, the dBm power signals of the first and second sensing units 121 and 122 having different power values may be converted into one dB. Can be processed with index tables.

According to an embodiment, the microcontroller 130 converting the digital dBm power signal value into a linear index calculates a moving average value for each of the converted linear indexes, and calculates each of the calculated moving average values (ie, the moving average linear index). Search for the dB index corresponding to the dB index table. In addition, the microcontroller 130 generates a power control signal according to the dB index on which MA processing is performed according to the above-described method, and performs power control on the PA 160.

In order to perform the above-described operation, the microcontroller 130 performs a sample and hold (Sample and Hold: S / H) process on the analog dBm power signals provided by the first and second sensing units 121 and 122 to form a cascade. First and second S / H units 131 and 132 for generating an analog dBm power signal, Analog to Digital Conversion (ADC) unit 133 for converting the stepped analog dBm power signal into a digital dBm power value, and a digital dBm power value Converting the digital dBm power value by using a conversion equation for converting a to a dB index, a conversion constant substituted into the conversion equation, a dB index table, and a storage unit 135 storing the power control program and the conversion constants and the conversion equation. The control unit 135 converts the index and generates a digital power control signal according to the converted dB index.

In digitally performing power control such as AGC, it is very important to quickly convert a measured analog signal into a digital signal. In particular, when the power of the signal input to the PA 160 is rapidly changed, it is necessary to minimize the time delay due to the ADC to maintain a stable output power in the PA (160). The microcontroller 130 according to the above-described embodiment includes S / H units 131 and 132 including hardware S / H devices on the input and output sides, respectively, to convert analog voltage signals input from the detectors 121 and 122 into digital dBm power values. The time to convert to is minimized.

In another exemplary embodiment, the storage unit 130 of the microcontroller 130 classifies the digital dBm power value into a plurality of items according to their sizes, and includes a conversion constant table including conversion constants corresponding to each item for each item. It may include. Hardware devices of the PA power control system 100, for example, the first and second branch parts 111 and 112 and the first and second detector parts 121 and 122 may be operated according to the power of a signal input to the device. (Ie, input / output relational expression) may be slightly different. This means that the conversion equation should also be changed according to the power of the input signal. Accordingly, the control unit 135 of the microcontroller 130 includes a conversion constant table having a plurality of conversion constants classified according to the digital dBm power value, and when the digital dBm power value is input, it corresponds to the input digital dBm power value. The converted conversion constants are searched in a conversion constant table, and the inputted dBm power value is converted into a dB index using a conversion equation in which the found conversion constants are substituted. Accordingly, in converting the digital dBm power value into the dB index, the digital dBm power value may be converted into a dB index that is closer to the actual power of the signal input to or output from the PA 160.

Hereinafter, the storage unit 134 and the control unit 135 of the microcontroller 130 according to an embodiment will be described in detail.

FIG. 2 is a detailed block diagram of the storage unit illustrated in FIG. 1. 2, the storage unit 134 of the microcontroller 130 according to an embodiment of the present invention is a power control program storage unit 210 for storing a power control program, a conversion including at least one conversion constant A conversion constant table storage unit 220 storing a constant table and a dB index table storage unit 230 storing a dB index table. The power control program includes instructions related to the control operation of the microcontroller 130. Hereinafter, the dB index table, the conversion equation, and the conversion constant table stored in the storage unit 134 will be described in detail.

1. dB index table

In one embodiment, the dB index table may include a plurality of dB index and a linear index corresponding thereto. As an example, set the dB index to a 16 bit unsigned integer, set the dB range of the dB index table to 17.8125 dB to 57.125 dB, and increase dB each time dB index 1 increases. That is, the dB index table when the dB step (dB step) is set to 0.0625 dB is shown in Table 1 below.

dB index table   dB Linear index dB index 60 0 17.8125 61 One 17.875 ... ... ... 64010 484 48.0625 ... ... ... 515822 629 57.125

In Table 1, in addition to the dB index table stored in the storage unit 134, the dB corresponding to each dB index is shown beside. In Table 1, the relation between dB index and dB and the relation between linear index and dB are as follows.

Here, n denotes a dB index, dB [n] denotes a dB corresponding to dB index n, L [n] denotes a linear index corresponding to dB index n, and INT [] denotes a rounding, rounding or rounding operator. In Table 1 according to an embodiment, the reason why the dB index is used instead of the dB itself is that it is preferable to use the unsigned integer dB index instead of the real dB to perform the fixed-point operation in the microcontroller 130. The number of items that a dB index table can have is determined by the number of bits of the dB index, and the range of dB that can be expressed by the dB index table is determined by the number of items in the dB step and the dB index table.

2. Conversion formula (dBm-> dB index)

The power control program includes a conversion equation for converting a digital dBm power value into a dB index. The conversion equation should be set such that all of the input power of the PA 160 belonging to the input range of the PA 160 can be mapped to the dB index of the dB index table. Therefore, in setting the conversion equation, (1) the coupling loss of the first or second branch 111 and 112 in relation to the input power of (1) and (2) the PA 160 in relation to the dB index table. , (b) input / output relational expressions of the first or second sensing units 121 and 122, (c) operation characteristics of the ADC unit 133, and (d) the correspondence between the input power of the PA 160 and the dB index. .

In detail, the first and second detectors 121 and 122 measure the power of the input signal in units of dBm and output a voltage signal corresponding thereto, and the following relationship is established between the input signal and the output signal. do.

Where DPin is input power [dBm], S is slope, I is intercept, and DVout is output voltage [V]. S and I are unique values for each detector. From Equation 3, it can be seen that a linear relationship is established between the input power and the output voltage of the first and second sensing units 121 and 122.

On the other hand, when the ADC unit 133 receives Vout within 0 to 4.096V from the detectors 121 and 122 and outputs a 10-bit digital dBm power value ADC, the following relationship is established between DVout and the ADC (in the equation below). , 0.004 = 4.096 / 2 ^ 10).

On the other hand, as the first and second branch parts 111 and 112 branch the input signal at a predetermined ratio as described above, a loss of a predetermined ratio occurs in the power of the output signal, which is called a coupling loss. Therefore, the power of the signal input to the variable resistor unit 150 or PA 160 is as follows.

Here, TPin means input power [dBm] of PA 160, DPin means input power [dBm] of the first or second sensing units 121 and 122, and C means coupling loss [dB].

Now, a method of deriving a conversion equation using Equations 1 and 3 to 5 will be described. If you want to map any value TPin_ref [dBm] of the PA 160 input power to the dB index corresponding to dB_ref [dB] in the dB index table of Table 1, the PA 160 input power TPin [] and dB index n The following relation holds for the liver:

On the other hand, when the arbitrary value TPout_ref [dBm] of the PA 160 output power is to be mapped to the dB index corresponding to dB_ref [dB] in the dB index table of Table 1, the PA 160 output power TPout and dB index n The following relation holds for the liver:

If equations 3 to 6 (in the input side) or 3 to 5 and 7 (in the output side) are arranged around the dB index n and the digital dBm power value ADC, the following relation is established.

Where a is the transform slope and b is the transform intercept. INT [] is used because n is unsigned integer by definition. A and b are conversion constants of the conversion equation.

In one embodiment, the power control program storage unit 210 of the storage unit 134 stores the conversion equation of the form (8), the conversion constant table storage unit 220 of the storage unit 134 is at least one The transformed slope a and the transformed intercept b of the pair can be stored. In one embodiment, the conversion constant table storage unit 220 of the storage unit 134 may include an input side conversion constant pair for the PA 160 input side (the first branch 111 and the first detection unit 121) and An output side conversion constant pair for the PA 160 output side (the first branch 111 and the second detector 122) may be stored.

3. Adjustment of conversion constant

The detectors included in the first and second detectors 121 and 122 have an input / output relationship as shown in Equation 3, and the input / output relationship is shown in a data sheet provided by the manufacturer of the corresponding detector. In general, the sensor datasheets are provided according to the product type or product type of the sensor. However, the actual input and output relationships of a detector are often different for each detector from the data in the datasheet (ie, the slope S and intercept I of 3 in mathematics according to the datasheet differ from the actual S and I of the detector). Can be). In addition, in the case of the coupling loss of the first and second branches 111 and 112, the coupling loss C on the data sheet and the actual coupling loss C may be different.

For example, the input power input to the detector ranges from -25.1875 dBm to 14.125 dBm, with its output voltage ranging from -1.1974 V to 0.768.25 V according to the detector's datasheet, but the actual S and I are the data. The actual output voltage may be out of the above-described range because it is different from S and I depending on the sheet. In this case, when the digital dBm power value is converted into the dB index using a conversion equation obtained according to the data sheet, a value outside the range of the dB index provided by the dB index table may be calculated. There is a problem in that the control unit 135 can not perform accurate power control.

In order to solve this problem, the user of the PA power control system 100, using a test device (not shown), the actual S and I and the first and second branch (S and I) of the first or second sensing unit 121,122 ( After obtaining the actual coupling loss C of 111 and 112, the slope a and the intercept b, which are the conversion constants of the conversion equation, can be adjusted accordingly. Looking at the relationship between S, I and C and a and b, the change in S in Equation 3 affects a in Equation 8, and the change in I in Equation 3 or C in Equation 5 is affects b Therefore, when there is a difference between S according to the data sheet and the actual S, the slope a may be adjusted so that all of the input power of the PA 160 may be mapped to the dB index of the dB index table. And, if there is a difference between I and / or C according to the data sheet and actual I and / or C, the intercept b can be adjusted so that all of the input power of the PA 160 can be mapped to the dB index of the dB index table. . The procedure for adjusting the conversion constants (tilt a and intercept b) so that all of the input power of the PA 160 can be mapped to the dB index of the dB index table is detailed in FIG. 6 and the related description.

4. Correction of Conversion Constants and Conversion Constants Table

In deriving Equation 8, it is assumed that a linear relationship such as Equation 3 is established between the input power and the output voltage of the first and second sensing units 121 and 122. However, the first and second detectors 121 and 122 including the detector, which is a hardware device, have a nonlinear characteristic in which the transformed slope a and the transformed intercept b vary according to the magnitude of the input signal. In order to accurately reflect this nonlinear input / output relationship of the first and second sensing units 121 and 122, a conversion constant table may be used as described above. In detail, the conversion constant table divides the range of the digital dBm power value into a plurality of sections, and converts the conversion constants that more accurately reflect the input / output relationship of the first or second sensing units 121 and 122 in the corresponding section for each section ( For example, slope a and transform intercept b).

In one embodiment, the conversion constant table storage unit 220 is an input side conversion constant table for the PA 160 input side (first detection unit 121) and the PA 160 output side (second detection unit 122) You can store the output conversion constant table for. In one embodiment, in order to obtain the conversion constant table, a method of dividing a range of dBm power value into a plurality of sections using a calibration device (not shown) and obtaining the conversion constant for the corresponding section is shown in FIGS. 7 and 9. And their descriptions in detail.

3 is a detailed block diagram of the control unit shown in FIG. 1. Referring to FIG. 3, the control unit 135 of the microcontroller 130 according to an embodiment of the present invention receives a digital dBm power value from the ADC unit 133 and converts it into a dB index. A dB index table search unit 320 for searching a linear index corresponding to the converted dB index in a dB index table, a MA generator 330 for calculating a moving average value for the searched linear index, and the calculated moving average value It includes a power control signal generator 340 for performing power control according to the dB index corresponding to.

In one embodiment, the dB index converter 310 may be provided with an input side / output side conversion equation for converting the input / output digital dBm power value to a dB index. The dB index converter 310 may search for input / output conversion constants corresponding to the input / output digital dBm power value received from the input / output conversion constant table stored in the conversion constant table storage 220. The dB index converter 310 may substitute the searched input / output conversion constant into the input / output conversion equation, and obtain a dB index for the input digital dBm power using the conversion equation.

The dB index table search unit 320 may search the linear index corresponding to the converted dB index in the dB index table, and provide the searched linear index to the MA processing unit 330. The dB index table search unit 320 may receive a moving average value from the MA processing unit 330 and search for a dB index corresponding thereto.

The power control signal generator 340 may generate the power control signal according to the dB index corresponding to the moving average value. In one embodiment, the power control signal generator 340 may include an ALC processor 341 and an AGC processor 342 for performing ALC and AGC for the PA 160, respectively.

The ALC processor 341 generates a power control signal such that the PA 160 input power or output power is kept below a predetermined level. In one embodiment, the ALC processor 341 may include an ALC flag for activating or deactivating the ALC processor 341. For example, when the ALC flag is set to “ON,” the ALC processing unit 341 may be activated to execute an ALC routine for the PA 160. On the other hand, when the ALC flag is set to "OFF", the ALC processing unit 341 may be inactivated to not execute the ALC routine for the PA 160. The ALC processing unit 341 may set the ALC flag to “on” when the input side dB index is smaller than a preset ALC off threshold. On the other hand, when the input side dB index is larger than the preset ALC on threshold, the ALC processor 341 sets the ALC flag. Can be set to "off". In addition, the ALC processing unit 341 may set the ALC flag to “on” when the output side dB index is larger than a preset maximum limit threshold.

When the ALC flag is set to “on”, the ALC processor 341 may adjust the power attenuation of the variable resistor unit 150 according to a difference between the input and output dB indices (that is, the dB index delta). In addition, the ALC processor 341 may adjust the power attenuation of the variable resistor unit 150 according to the output side dB index.

An embodiment of pseudocode for implementing the above-described ALC processing operation is shown below.

ALC_Routine ()

{

CASE: if dB_Index_input <ALC OFF threshold

ALC_Flag = OFF;

CASE: if ALC_Flag is ON or

dB_Index_input> ALC ON threshold or

dB_Index_output> max limit threshold

{

ALC_Flag = ON;

CASE: if dB_Index_output> max limit threshold

attenuation increased significantly;

CASE: if dB_Index_output ≤ max limit threshold

CASE: if dB_Index_Delta> upper threshold or

dB_Index_output> limit upper threshold

less attenuation;

CASE: if dB_Index_Delta <Min lower threshold and

dB_Index_output <limit lower threshold

attenuation greatly reduced;

CASE: if dB_Index_Delta <Normal

less attenuation;

}

}

The AGC processor 342 generates a power control signal so that the gain between the PA 160 input power or output power is kept constant. In one embodiment, the AGC processing unit 342 may activate the AGC processing unit 342 to execute the AGC routine for the PA 160 when the ALC flag is set to "off". As can be seen from equations (6) and (7), knowing the input side dB index can obtain the PA 160 input power, and knowing the output side dB index can obtain the PA 160 output power. Therefore, the power control signal can be generated such that the gain between the input power and the output power is kept constant by using the difference between the input and output dB indices (that is, the dB index delta). In one embodiment, the AGC processing unit 342 generates a power control signal to adjust the attenuation rate of the variable resistor unit 150 according to the size of the dB index delta.

An embodiment of pseudocode for implementing the above-described AGC processing operation is shown below.

AGC_Routine ()

{

CASE: if ALC_Flag is OFF

{

CASE: if dB_Index_Delta> Max upper threshold

attenuation increased significantly;

CASE: if dB_Index_Delta> upper threshold

less attenuation;

CASE: if dB_Index_Delta <Min lower threshold

attenuation greatly reduced;

CASE: if dB_Index_Delta <lower threshold

less attenuation;

}

}

4 is a flowchart illustrating a method for controlling PA power of a microcontroller according to an embodiment of the present invention. 4, the control unit 135 of the microcontroller 130 according to an embodiment of the present invention stores the conversion equation, the conversion constant table and the dB index table in the storage unit 134 (S400). In one embodiment, the conversion equation is a linear equation that inputs a digital dBm power value output from the ADC unit 133 and outputs a dB index, and may have a slope and an intercept as a conversion constant (that is, y = a * x + b, where y is the dB index, x is the dBm power value, and a and b are the slope and intercept, respectively). In step S410, the control unit 135 receives the dBm power values of the RF input terminal and the RF output terminal from the ADC unit 133, and retrieves the conversion constants corresponding to the input dBm power value in the stored conversion constant table ( S420). In operation S430, the controller 135 substitutes the found conversion constant into the stored conversion equation and calculates a dB index corresponding to the input dBm power value by using the conversion equation in which the searched conversion constant is substituted.

In step S440, the controller 135 retrieves the linear index corresponding to the calculated dB index from the stored dB index table, and calculates a moving average value for the retrieved linear index (S450). For example, the retrieved linear index is W [n] = 10 (where n is the time index of the retrieved linear index) and is located within a time window (eg, length = 2) for calculating a moving average. If the previously retrieved linear indices W [n-1] and W [n-2] are 20 and 6, respectively, the moving average value for time index n is 20 + 6 + 10/3 = 12. In operation S460, the controller 135 searches for the dB index corresponding to the calculated moving average value (12 in the above-described example) in the stored dB index table. In step S470, the controller 135 performs power control on the PA 160 using the searched dB index, and ends the procedure.

5 is a flowchart illustrating an ALC and AGC power control method of a microcontroller according to an embodiment of the present invention. Referring to FIG. 5, the controller 135 of the microcontroller 130 obtains an input dB index for an input signal to the PA 160 and an output dB index for an output signal from the PA 160 (S500). In operation S510, the controller 135 determines whether the input dB index is smaller than a preset ALC off threshold. If it is determined in step S510 that the input dB index is smaller than the preset ALC off threshold, the controller 135 sets the ALC flag to "off" (S560) and ends the procedure. On the other hand, if it is determined in step S510 that the input dB index is smaller than the preset ALC off threshold, the controller 135 determines whether the ALC flag is set to "on" (S520).

If it is determined in step 520 that the ALC flag is set to “ON”, the controller 135 performs ALC using the input and output dB indexes (S580) and ends the procedure. If it is determined in step S520 that the ALC flag is not set to “on”, the controller 135 determines whether the input dB index is greater than a preset ALC on threshold (S530). As a result of the determination in step 530, when the input dB index is not greater than the preset ALC on threshold, the controller 135 determines whether the output dB index is greater than the preset maximum limit threshold (S540). As a result of the determination in step S540, when the output dB index is not greater than a preset maximum limit threshold, the controller 135 performs ALC using the input and output dB indexes (S580) and ends the procedure. On the other hand, if it is determined in step S530 that the input dB index is greater than the preset ALC on threshold, or if it is determined in step S540 that the output dB index is greater than the preset maximum threshold threshold, the controller 135 sets the ALC flag to "on". Set (S570), go to step S580.

6 is a flowchart of a method of adjusting a conversion constant of a microcontroller according to an embodiment of the present invention. Referring to FIG. 6, a test apparatus (not shown) according to an embodiment of the present invention inputs a test signal within a predetermined range to the first sensing unit 121 of the PA power control system 100 (S600). The output signal output from the first detection unit 121 is measured (S610). In operation S620, the test equipment calculates dB indices corresponding to the measured output signal using a preset conversion equation. For example, the test apparatus may convert the measured output signal into digital dBm power values and input the converted digital dBm power values into the conversion equation to obtain a series of dB indices. In one embodiment, the preset conversion equation may be a conversion equation set based on data provided in the data sheet of the first sensing unit 121.

In operation S630, the test apparatus determines whether the calculated range of dB indices matches the range of dB indices of a preset dB index table. For example, if the range of dB index provided by the dB index table is 0 to 629, the test apparatus determines whether the calculated range of dB indices falls within the range. If it is determined in step S630 that the calculated range of dB indices coincides with the range of dB indices of the preset dB index table, the procedure ends.

On the other hand, if it is determined in step S630 that the range of the calculated dB indices does not match the range of the dB index of the preset dB index table, the test apparatus determines that the range of the calculated dB indexes is the dB index of the dB index table. The conversion constants of the conversion equation are adjusted to match the range (S640). In step S650, the test apparatus stores the adjusted conversion constants in the storage unit 134 of the microcontroller 130 as conversion constants for the RF input side conversion equation of the PA power control system 100 (S650). To exit.

Although the procedure of adjusting the conversion constant for the RF input side conversion equation of the PA power control system 100 has been described with reference to FIG. 6, the procedure illustrated in FIG. 6 is applied to the second detection unit 122 for the RF output side conversion equation. You can adjust the conversion constants. 6 illustrates a procedure for reflecting the difference between the range of the operating area and the range of the actual operating area according to the data sheets of the detectors 121 and 122 in the conversion equation, but the test signal is applied to the first and second branch parts 112. And performing the steps S620 to S650 shown in FIG. 6, the difference between the datasheet and the actual operating characteristic (eg, coupling loss) of the first and second branch 112 is converted into conversion constants. Can be reflected in the

The above-described dBm power value-dB index conversion formula and its conversion constants are linear in the input / output operation of the first and second branch parts 111 and 112 and the first and second sensing parts 121 and 122 of the PA power control system 100. Induced on the assumption that they have characteristics, but as with all physical devices, they actually exhibit non-linear characteristics. Therefore, according to an embodiment of the present invention, the microcontroller 130 includes a conversion constant table for correcting the conversion constants according to the nonlinear characteristics described above.

7 is a flowchart illustrating a method of preparing a conversion constant table of a microcontroller according to an embodiment of the present invention. Referring to FIG. 7, a calibration device (not shown) according to an embodiment of the present invention inputs a test signal to an RF input terminal of the PA power control system 100 (S700). In one embodiment, the test signal may be a signal (eg, monotonic increase signal) whose magnitude or power gradually increases within a predetermined range. At this time, to ensure that the test signal does not deviate from the input allowable range of the PA power control system 100, the calibration apparatus measures the power consumption of the PA 160 of the PA power control system 100, and the measured consumption The resistance value of the variable resistor unit 150 of the PA power control system 100 is controlled to maintain the power below a preset threshold (S710). In operation S720, the calibration apparatus provides a power of a signal input to the PA 160 using a power meter (for example, the first branch 111 to the variable resistor unit 150 according to the input test signal). Measure the power of the signal to collect a series of power meter measurement values ("PM value"). At the same time, the calibration apparatus collects digital dBm power values for the test signal input from the ADC unit 133 (S730).

In operation S740, the calibration apparatus calculates inflection points among the series of PM values based on the collected series of PM values, and sets each of the calculated inflection points as a reference point. In operation S750, the calibration apparatus substitutes PM values and dBm power values at the reference points among the collected PM values and dBm power values into preset calibration equations, and calculates the conversion constants corrected for each section between the reference points. do. For example, when the equation for converting the digital dBm power value output from the ADC unit 133 into the dB index is y = INT [a * x + b] form (where y is the dB index and x is the dBm power value). , The conversion constants a and b are the slopes and intercepts, respectively, and the correction equations for calculating the conversion constants a and b for each section may be as follows.

Where n and n + δ are time indices, a [n, n + δ] is the slope in the interval [n, n + δ], PM [] is the PM value, and ADC [] is output from the ADC unit 133 One digital dBm power value, Δ means dB step of the dB index table, K means TPin_ref-dB_ref + Least_dB (in the input side) or TPout_ref-dB_ref + Least_DB (in the output side). Here, Least_dB means the lower dB (17.8125 in the case of Table 1 and Equation 1) of the dB of the dB index table.

Equation 9 may be derived using Equations 6 to 8. Specifically, the following relation is established by substituting Equation 8 without the INT [] operator into Equation 6 or 7.

Further, since TPin [n] is the same as the input side PM [n], the following relation holds.

If equations 10 and 11 are set as equations and centered on a [] and b [], equations (9) can be obtained.

The calibration apparatus obtains a plurality of dBm power value intervals corresponding to the intervals between the plurality of reference points (see FIG.), And includes an input-side conversion constant table including the plurality of dBm power value intervals and the conversion constants corresponding to the respective intervals. Create Then, it is stored in the storage unit 134 of the microcontroller 130 (S760), and the procedure ends.

The microcontroller 130 having the conversion constant table checks which section of the conversion constant table the dBm power value input from the first sensing unit 121 searches for the conversion constant corresponding to the section, and searches for the searched constant. The dB index of the input dBm power value is obtained using the conversion constant. The first branching unit 111 and the section for classifying the dBm power value input from the first sensing unit 121 are set according to the inflection points of the series of PM values, and the conversion constant applied according to the set section is changed. Nonlinear characteristics of the first sensing unit 131 can be effectively compensated with a small amount of association.

8 is a detailed flowchart of step S710 shown in FIG. Referring to FIG. 8, a calibration device (not shown) according to an embodiment of the present invention measures a driving current input to the PA 160 through the galvanizing unit 180 of the PA power control system 100 (S800). In operation S810, power consumption of the PA 160 is calculated according to the measured driving current. Since the driving voltage supplied to the PA 160 is constant at Vcc, when the magnitude of the driving current Icc input to the PA 160 is known, power (P = Vcc * Icc) consumed by the PA 160 can be calculated. Can be.

In operation S830, the calibration apparatus determines whether the calculated power consumption is greater than a preset threshold. In operation S830, when the calculated power consumption is not greater than a preset threshold, the calibration apparatus activates the ALC processor 341 and the AGC processor 342 of the controller 135 of the microcontroller 130 (S850). The controller 135 directly performs power control of the signal input to the PA 160, and ends the procedure. On the other hand, if it is determined in step S830 that the calculated power consumption is greater than a preset threshold, the calibration apparatus deactivates the ALC processor 341 and the AGC processor 342 of the controller 135 of the microcontroller 130 (S830). ), The variable resistance unit 150 of the PA power control system 100 is directly controlled by the calibration apparatus to reduce the power of the signal input to the PA 160 (S840), and the procedure ends.

An example of pseudocode for implementing the procedure shown in FIG. 8 is shown below. In the pseudo code below, over current consumption limiting is the name of the pseudo code, current consumption is the power consumption of the PA 160, attenuation is the signal attenuation rate in the variable resistor unit 150, current_protection_flag is the activation of the ALC and AGC processing unit 341,342 Flags indicating whether or not, threshold and normal means a threshold.

over current consumption limiting ()

{

if (current consumption> threshold)

{

increase attenuation;

current_protection_flag = ON;

}

else if (current_protection_flag == ON)

{

if (attenuation> normal)

decrease attenuation;

else if (attenuation == normal && current consumption <threshold)

{

current_protection_flag = off;

}

}

}

FIG. 9 is a detailed procedure diagram of step S740 shown in FIG. 7. 9, a calibration device (not shown) according to an embodiment of the present invention includes a series of PM values collected through a power meter, that is, PM [0], ... PM [n] ..., PM A smoothing process (for example, a MA process) is performed on [N] (where the number in [] is a time index) (S900). In operation S910, the calibration apparatus sets a weight to be used for inflection point detection.

In step S920, the exchange apparatus determines, with respect to each PM value, a first slope in a negative direction and a second in a positive direction on a time axis of a PM [n] (PM value) versus n (time index) graph. Calculate the slope For example, for PM [n], the first slope refers to the slope between PM [n] and PM [n-1], and the second slope refers to the slope between PM [n] and PM [n + 1]. All. In operation S930, the exchange apparatus corrects each of the calculated first and second slopes according to the set weight, determines whether the modified first and second slopes are the same, and classifies the same PM values into inflection points. (S940). For example, after multiplying each of the calculated first and second slopes by the set weight, and rounding up, down, or rounding the result values, it is determined whether the two result values are the same. The higher the weight, the more accurately it is possible to determine whether the first and second slopes are equal.

In operation S950, the exchange apparatus determines whether the number of the classified inflection points is smaller than a preset threshold. In operation S950, when the number of the classified inflection points is not smaller than a preset threshold, the exchange apparatus resets the set weight to another value (for example, resets to a value smaller than the set weight) (S970). Go to step S920. On the other hand, if it is determined in step S950 that the number of the classified inflection points is smaller than a preset threshold, the exchange apparatus sets each of the classified inflection points as a reference point (S960), and ends the procedure.

An example of pseudocode for implementing the procedure shown in FIG. 9 is shown below.

reference point detection ()

{

perform moving average process to collected data;

for (collected data)

point [] = 1;

weight = 2000;

while (weight)

{

for (n <# of collected data)

{

slope1 = slope between point [n-1] and point [n];

slope2 = slope between point [n] and point [n + 1];

slope1 = slope1 * w

slope2 = slope2 * w

if ((int) slope1! = (int) slope2)

{

point [n] = 1;

# of selected points ++;

}

else

point [n] = 0;

}

if (# of selected points <threshold)

{

select point [n] = 1 as an inflection point

return;

}

weight--:

}

}

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications and changes within the scope of the technical spirit of the present invention for those skilled in the art to which the present invention pertains. Changes may be made, but such substitutions, changes and the like should be regarded as belonging to the following claims.

1 is a conceptual diagram of a power amplifier control system according to an embodiment of the present invention.

FIG. 2 is a detailed block diagram of the storage unit shown in FIG. 1. FIG.

3 is a detailed block diagram of the controller shown in FIG. 1;

4 is a flowchart of a method for controlling PA power of a microcontroller according to an embodiment of the present invention.

5 is a flow chart of the ALC and AGC power control method of the microcontroller according to an embodiment of the present invention.

6 is a flowchart illustrating a method of adjusting a conversion constant of a microcontroller according to an embodiment of the present invention.

7 is a flowchart of a method of preparing a conversion constant table of a microcontroller according to an embodiment of the present invention.

8 is a detailed procedure of step S710 shown in FIG.

9 is a detailed procedure diagram of step S740 shown in FIG.

Claims (12)

A power control system including a power amplifier and a power control device for controlling the power of an input signal input to the power amplifier, An attenuation unit attenuating the input signal according to a power control signal and outputting an attenuation signal; A power amplifier for power amplifying the attenuated signal and outputting an amplified signal; A first sensing unit measuring a power of the input signal and calculating a series of first power values; A second sensing unit measuring a power of the amplified signal and calculating a series of second power values; And A power control unit which generates the power control signal based on the series of first and second power values; The power control unit, A first converter for converting the series of first power values into a series of first dB indices, a first searcher for searching for a series of linear indices corresponding to the converted series of dB indices, and the series of linear indices A first control unit including a first moving average value generating unit generating a series of first moving average values MA; A second converter for converting the series of second power values into a series of dB indices, a second searcher for searching for a series of linear indices corresponding to the converted series of dB indices, and a series of the series of linear indices A second control unit including a second moving average value generating unit configured to generate a second moving average value MA; And And a power control signal generator configured to generate the power control signal using the series of first moving average values and the series of second moving average values. The method of claim 1, The first conversion unit stores a first conversion equation for calculating a series of dB indices corresponding to the series of first power values, wherein the first conversion equation includes at least one first conversion constant; And the second conversion unit stores a second conversion equation for calculating a series of dB indices corresponding to the series of first power values, the second conversion equation including at least one second conversion constant. . The method of claim 2, First and Second Conversion Constant Tables-The first and second conversion constant tables each include at least one first and second power value intervals and first and second corresponding to each of the first and second power value intervals, respectively. Further comprising a storage for storing the conversion constants. The method of claim 3, The first conversion unit searches for the first conversion constants corresponding to the first power value interval to which the respective first power value belongs in the first conversion constant table for each of the first power value, and the retrieved first conversion constant Calculate the dB index corresponding to each of the first power values by substituting the above equation into the first conversion equation, The second converter searches for the second conversion constants corresponding to the second power value interval to which the second power value belongs in the second conversion constant table for each second power value, and the retrieved second conversion constant Calculating the dB index corresponding to each of the second power values by substituting the same into the second conversion equation. The method of claim 1, a dB index table, the dB index table further comprising a storage for storing a series of dB indexes and a series of linear indices respectively corresponding to the series of dB indices, The first search unit searches a series of linear indexes corresponding to a series of dB indexes converted from the first power values in the dB index table, And the second search unit searches a series of linear indexes corresponding to a series of dB indexes converted from the second power values in the dB index table. The method of claim 5, The first search unit searches a series of first dB indexes corresponding to the series of first moving average values in the dB index table, The second search unit searches a series of second dB indexes corresponding to the series of second moving average values in the dB index table, And the power control signal generator generates the power control signal using the searched first and second dB indices. A method of generating a conversion constant table for power control, Generating and inputting a test signal to a power amplifier, the power amplifier outputting an amplified signal in response to the input of the test signal; Branching the amplified signal to provide first and second branch signals; Measuring power of the first branch signal to provide a series of first power values; Measuring the power of the second branch signal to provide a series of second power values; Calculating inflection points of the series of second power values; Determining at least one power value interval using the calculated inflection points; Calculating conversion constants for the determined power value intervals using the series of first and second power values; And Storing the determined power value intervals and the calculated conversion constants for the determined power value intervals in correspondence with the conversion constant table, respectively. Method for generating a conversion constant table for power control, including. The method of claim 7, wherein The input step Measuring a driving current supplied to the power amplifier; And Attenuating the test signal according to the measured driving current How to include. The method of claim 7, wherein The test signal is a signal in which the power or magnitude of the signal monotonically increases with time. A method of controlling the power of a signal input to a power amplifier using the conversion constant table generated according to claim 7, Converting a power value of a signal output from the power amplifier to a dB index using the conversion constant table; And Controlling the power of the signal input to the power amplifier using the converted dB index How to include. A method of generating a conversion constant table for power control, Branching a test signal for a power amplifier to provide first and second branch signals, wherein the first branch signal is input to the power amplifier and the second branch signal is input to a detector of the power amplifier; Measuring power of the first branch signal to provide a series of first power values; Measuring the power of the second branch signal to provide a series of second power values; Calculating inflection points of the series of second power values; Determining at least one power value interval using the calculated inflection points; Calculating conversion constants for the determined power value intervals using the series of first and second power values; And Storing the determined power value intervals and the calculated conversion constants for the determined power value intervals in correspondence with the conversion constant table, respectively. Method for generating a conversion constant table for power control, including. A method of controlling power of a signal input to a power amplifier using a conversion constant table generated according to claim 11, Converting a power value of a signal input to the power amplifier into a dB index using the conversion constant table; And Controlling the power of the signal input to the power amplifier using the converted dB index How to include.

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