KR101376898B1 - Bias controlling apparatus - Google Patents

Abstract

The present invention provides a temperature compensation circuit for generating a digital signal corresponding to the temperature of a transistor and outputting a compensation bias current obtained by adding or subtracting a control current to a reference bias current using the generated digital signal, and a mirror transistor connected in parallel with the transistor. Bias control including a characteristic compensation circuit for detecting a characteristic error of the output signal, and outputting a compensation signal for compensating for the characteristic error, and a bias compensation circuit for compensating and outputting a bias power applied to the transistor using the compensation bias current and the compensation signal. The device can improve the performance of the transistor.

Description

Bias controlling apparatus

The present invention relates to a bias control device, and more particularly, to a bias control device capable of automatically compensating for a change in temperature or an error in a bias power supply generated during manufacture.

In general, a power amplifier is used to transmit and receive a signal wirelessly in a wireless communication system such as a mobile communication terminal. Here, the power amplifier refers to a device that amplifies a fine signal into a large signal with little distortion and efficiently supplies it to a load through an antenna.

These power amplifiers include CMOS power amplifiers designed with special semiconductor GaAs process and general CMOS (CMOS) process.These CMOS power amplifiers can be mass-produced, resulting in low cost and various functions. There is this.

Meanwhile, in order to stably control the operation of the power amplifier, a power regulator of the power amplifier has been developed, and a technology for supplying more stable power to the power amplifier using the power regulator has been researched and developed.

The power amplification system according to the prior art is applied to a power amplifier using a voltage controller for providing a constant voltage corresponding to a reference voltage to the power amplifier, a current controller for adjusting the driving current according to an input control voltage, and a driving voltage and a driving current. It includes a bias controller for controlling the bias power supply, and adjusts the bias power appropriately according to the input control voltage to supply a stable current to the power amplifier.

However, at room temperature, the power amplifier performs power amplification in the correct operating region, but the characteristics of the power amplifier do not change. However, when the temperature changes, the characteristics of the power amplifier change according to the temperature, thereby causing performance degradation.

In particular, the power amplifier is sensitively changed in operation characteristics according to the change in the bias power applied, such a bias power supply can be easily changed by the change of temperature or the process change during manufacturing.

Accordingly, the performance of the power amplifier should be improved by adjusting the bias power applied to the power amplifier. However, there is a problem in that the characteristics of the power amplification system deteriorate because there is no compensation circuit for adjusting the bias power applied.

Accordingly, there is a need in the art for a method of properly adjusting a bias power supply of a power amplifier that is varied by a change in temperature or a process change during manufacturing.

The idea of the present invention relates to a bias control device that can improve the performance of a transistor by automatically compensating for an error in a bias power supply caused by a change in temperature or a process change during manufacturing.

To this end, the bias control apparatus according to an embodiment of the present invention generates a digital signal corresponding to the temperature of the transistor, and outputs a compensation bias current obtained by adding or subtracting a control current to a reference bias current using the generated digital signal. A temperature compensation circuit; A characteristic compensation circuit which detects a characteristic error of a mirror transistor connected in parallel with the transistor and outputs a compensation signal for compensating the characteristic error; And a bias compensation circuit for compensating and outputting a bias power applied to the control terminal of the transistor by using the compensation bias current and the compensation signal, wherein the characteristic error is at least one of a deviation between the transconductance and the threshold voltage of the mirror transistor. It may be an error due to any deviation.

Here, the temperature compensation circuit includes a temperature detector for detecting a temperature voltage corresponding to the temperature; A conversion unit converting the detected temperature voltage into a digital signal and generating the digital signal; And a current controller configured to add or subtract the control current to the reference bias current according to the converted digital signal to output the compensation bias current.

The temperature compensation circuit may further include a reference voltage generator configured to generate a first reference voltage and output the first reference voltage to the converter.

In this case, the converter comprises a plurality of comparators for comparing the temperature voltage and the first reference voltage according to the section divided by temperature, and outputs a comparison signal as a result of the comparison; And a generator configured to combine the plurality of comparison signals to generate the digital signal.

The current control unit may include a control signal output unit configured to output a temperature control signal using the generated digital signal; A reference bias generator for controlling the reference bias current to flow; And a current controller connected in parallel with the reference bias generator and controlling to add or subtract the control current to the reference bias current according to the temperature control signal.

Here, the current controller includes a plurality of current sources connected in series with the power supply voltage VDD; It may include a plurality of switches connected in series with the plurality of current sources, and selectively connected according to the temperature control signal.

More specifically, the current controller can selectively connect a switch located adjacent to the power supply voltage to add the control current to the reference bias current.

In addition, the current controller may selectively connect a switch located adjacent to ground to subtract the control current to the reference bias current.

The characteristic compensation circuit may include a characteristic comparator configured to compare the voltage according to the drain-source current of the mirror transistor with a preset second reference voltage and detect the characteristic error as a result of the comparison.

In addition, the characteristic compensation circuit may further include a feedback controller configured to generate a compensation signal for compensating the characteristic error by using the detected characteristic error, and output the compensation signal to the mirror transistor and the transistor, respectively. .

In addition, the characteristic comparing unit and the feedback adjusting unit may repeat the operation of detecting the characteristic error and outputting the compensation signal until the voltage of the mirror transistor is equal to the second reference voltage.

The characteristic compensation circuit may further include a current mirror unit for mirroring a current flowing through the mirror transistor, and the characteristic comparison unit may compare the voltage corresponding to the current mirrored by the current mirror unit with the second reference voltage.

In this case, the mirror transistor has the same structure as the transistor and may be smaller in size than the transistor.

In more detail, when the transistor is m size, the mirror transistor may be 1 / m size of the transistor.

The transistor may be a power amplifier.

As described above, according to the bias control apparatus according to an embodiment of the present invention, the performance of a transistor can be improved by automatically compensating a bias power applied to the transistor according to an error caused by a change in temperature or a process change during manufacturing. There are advantages to it.

More specifically, to solve the problem that the bias power is changed in accordance with the error caused by the temperature change or the process change during manufacturing, the operation characteristics of the transistor (for example, the power amplifier) is changed and performance degradation may occur. The transistor's bias supply can be automatically compensated to ensure that the transistor always operates at optimal operating characteristics.

Accordingly, there is an advantage that can improve the reliability of the transistor and the power amplification system including the same.

1 is a schematic configuration diagram of a bias control apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of the temperature compensation circuit shown in FIG. 1.
FIG. 3 is a detailed configuration diagram of the converter shown in FIG. 2.
4A is a diagram illustrating an operation of a switch for adding a control current to a reference bias current in the current controller shown in FIG. 2.
4B is a diagram illustrating an operation of a switch for subtracting a control current from a reference bias current in the current controller shown in FIG. 2.
5 is a configuration diagram of the characteristic compensation circuit shown in FIG. 1.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

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

1 is a schematic configuration diagram of a bias control apparatus according to an embodiment of the present invention, and FIG. 2 is a configuration diagram of a temperature compensation circuit shown in FIG.

1 and 2, the bias control device 1 includes a temperature compensation circuit 100, a characteristic compensation circuit 200, and a bias compensation circuit 300.

First, before describing the components of the bias control device 1 in detail, the bias control device will be briefly described. The bias control device 1 is a device for controlling a bias power source that is normally applied to the transistor 400. For example, when the transistor 400 is a power amplifier, the bias control device 1 may be installed in a power amplification system to control a bias power supply of the power amplifier.

However, the bias control device 1 is not limited to this, and may be applied to various systems and used.

Hereinafter, the components of the bias control device according to an embodiment of the present invention will be described in detail with reference to FIG. 2.

The temperature compensation circuit 100 generates a digital signal corresponding to the temperature of the transistor 400, that is, the temperature of the surrounding environment in which the transistor 400 is located, and according to the generated digital signal, the reference bias current I is generated. The control bias currents I1 and I2 are added or subtracted to output the compensation bias current Io.

The temperature compensating circuit 100 may include a temperature detector 110, a reference voltage generator 120, a converter 130, and a current controller 140, among which the temperature detector 110 is a temperature sensor. In order to detect a change in the temperature, a temperature voltage corresponding to the temperature of the current transistor 400 may be output. In other words, the temperature detector 110 may detect the temperature of the surrounding environment in which the transistor 400 is located as a voltage V, not a concept of several degrees Celsius (° C.).

The reference voltage generator 120 generates a first reference voltage Vref1 and outputs the first reference voltage Vref1 to the converter 130. The detailed configuration of the reference voltage generator 120 as described above will be described in more detail below.

The converter 130 converts the temperature of the transistor 400, that is, the temperature of the surrounding environment in which the transistor 400 is located, into a digital signal.

FIG. 3 is a detailed configuration diagram of the converter illustrated in FIG. 2, which will be described in more detail with reference to FIG. 3. The converter 130 may include a plurality of comparators 132a to 132n and a generator 134. .

Among these, the plurality of comparators 132a to 132n compare the temperature voltage VPTAT and the first reference voltage Vref1 according to sections divided by temperature, respectively, and generate a plurality of comparison signals as a result of the comparison. Can be printed as

More specifically, the plurality of comparators 132a to 132n divide sections according to temperature and compare the temperature voltage VPTAT and the first reference voltage Vref1 according to the divided sections, respectively. When the temperature voltage VPTAT is less than the first reference voltage Vref1, a high level comparison signal is output. On the contrary, when the temperature voltage VPTAT is greater than or equal to the first reference voltage Vref1, the low value is low. ) Level comparison signal can be output.

Here, the first reference voltages Vref1 are voltages applied to the plurality of comparison resistors R11 to R1n, respectively, and are different from the plurality of comparators 132a to 132n according to the values of the comparison resistors R11 to R1n. The reference voltage Vref1 may be applied.

Next, the generator 134 may generate a digital signal by combining a plurality of comparison signals respectively output from the plurality of comparators 132a to 132n.

For example, when the plurality of comparators are configured with the first to third comparators 132a to 132c which are three comparators, the high level comparison signal, the high level comparison signal, and the first to third comparators 132a to 132c may be used. When the low level comparison signals are respectively output, the generator 134 may combine them to generate a binary value of "110", that is, a digital signal.

Meanwhile, referring back to FIG. 2, the current controller 140 adds or subtracts the control current I1 or I2 to the reference bias current I according to the digital signal converted by the converter 130 to compensate for the bias current. Outputs (Io).

The current controller 140 may include a control signal output unit 142, a reference bias generator 144, and a current controller 146. The control signal output unit 142 may include a digital signal generated by the generator 134. Output temperature control signal using. In other words, the control signal output unit 142 may generate and output a temperature control signal for controlling the current controller 146 using the digital signal generated by the generator 134.

The reference bias generator 144 includes a plurality of bias resistors R1 and R2 to control the reference bias current I to flow.

The current controller 146 is connected in parallel with the reference bias generator 144 and is a means for controlling to add or subtract the control currents I1 and I2 to the reference bias current I in accordance with the temperature control signal, and a plurality of currents. It may be composed of a plurality of switches (SW1, SW2) for controlling the source (S1, S2) and a plurality of current sources (S1, S2).

Here, the plurality of current sources S1 and S2 may be connected in series with respect to the power supply voltage VDD, and may be connected between the connection points between the plurality of current sources S1 and S2 and the plurality of bias resistors R1 and R2. The connecting points can be connected to each other.

In addition, the plurality of switches SW1 and SW2 may be connected in series with the plurality of current sources S1 and S2 to be selectively connected according to the temperature control signal.

Hereinafter, the operation of the switch for adding or subtracting the control current to the reference bias current in the current controller will be described in more detail.

4A is a diagram illustrating an operation of a switch for adding a control current to a reference bias current in the current controller shown in FIG. 2, and FIG. 4B is a diagram for subtracting a control current to a reference bias current in the current controller shown in FIG. 2. The figure which shows the operation process of a switch is shown.

Referring to FIG. 4A, the current controller 146 may add the first control current I1 to the reference bias current I by connecting the first switch SW1 adjacent to the power supply voltage VDD. In other words, the current controller 146 selectively connects the first switch SW1 adjacent to the power supply voltage VDD and applies the reference bias current I to the reference bias current I from the first current source S1 according to the temperature control signal. By adding the first control current I1, the compensation bias current Io may be set higher than the preset reference gate bias current.

Referring to FIG. 4B, the current controller 146 may connect the second switch SW2 adjacent to the ground GND to subtract the second control current I2 from the reference bias current I. FIG. In other words, the current controller 146 selectively connects the second switch SW2 adjacent to the ground GND according to the temperature control signal, and is applied to the reference bias current I from the second current source S2. By subtracting the second control current I2, the compensation bias current Io may be set lower than the reference gate bias current.

Accordingly, the temperature compensation circuit 100 may adjust the bias current low or high according to the temperature change to more effectively compensate the bias power supply.

Hereinafter, a characteristic compensation circuit according to an embodiment of the present invention will be described.

FIG. 5 is a configuration diagram of the characteristic compensation circuit 200 shown in FIG. 1. Referring to FIG. 5, the characteristic compensation circuit 200 has a characteristic error of the mirror transistor M2 connected in parallel with the transistors 400 and M1. And a means for outputting a compensation signal for compensating for the characteristic error, may include a feature comparator 220, a feedback adjuster 240 and a current mirror 260.

First, the characteristic error will be described before the characteristic compensation circuit 200 is described. In general, the transistor M1 has a characteristic error due to a change in the transconductance Gm or a change in the threshold voltage Vth. May occur. Accordingly, the characteristic error of the transistor M1 should be compensated for, but the method of directly detecting the characteristic error in the transistor M1 has a problem of deteriorating characteristics or high power consumption.

Accordingly, in one embodiment of the present invention, the characteristic error of the transistor M1 is achieved by using the mirror transistor M2 having the same structure (W / L) as the transistor M1 and having a smaller overall size than the transistor M1. Can be detected.

If the mirror transistor M2 has the size of m, the transistor M1 is preferably 1 / m size of the transistor M1, and the mirror transistor M2 has the same characteristic error as that of the transistor M1. Therefore, the characteristic error of the mirror transistor M2 may be detected first to compensate for the characteristic error of the transistor M1.

In order to compensate for the characteristic error of the transistor, the characteristic comparison unit 220 compares the voltage of the mirror transistor M2 with a preset second reference voltage Vref2 and detects the characteristic error as a result of the comparison.

Next, the feedback controller 240 generates a compensation signal for compensating for the characteristic error by using the characteristic error detected by the characteristic comparator 220, and sends the compensation signal to the mirror transistor M2 and the transistor M1. Print each one.

In more detail, the characteristic comparison unit 220 and the feedback controller 240 detect a characteristic error until the voltage of the mirror transistor M2 is equal to the second reference voltage Vref2 and output a compensation signal. Repeat the operation.

For example, when the voltage of the mirror transistor M2 changes due to a process change, an error occurs in the characteristic of the mirror transistor M2, and the characteristic comparison unit 220 causes the mirror transistor M2 in the characteristic comparison unit 220 to perform the comparison operation. The characteristic error can be detected. Then, the feedback controller 240 generates a compensation signal for compensating for the characteristic error by using the characteristic error detected by the characteristic comparator 220 and converts the compensation signal into the mirror transistor M2 and the transistor M1, respectively. By outputting, the voltage of the mirror transistor M2 is controlled to be equal to the second reference voltage Vref2.

At this time, the compensation signal as described above is transmitted together with the mirror transistor M2 and the transistor M1 to finally compensate for the characteristic error in the transistor M1.

In addition, the characteristic compensation circuit 200 may further include a current mirror unit 260 for mirroring a current flowing in the mirror transistor M2 to detect the voltage of the mirror transistor M2.

Accordingly, the characteristic comparison unit 220 may compare the voltage of the mirror transistor M2 and the second reference voltage Vref2 corresponding to the current mirrored by the current mirror unit 260.

Finally, referring to FIG. 1, the bias compensation circuit 300 compensates and outputs a bias power applied to the transistor 400 using the compensation bias current and the compensation signal.

That is, the bias compensation circuit 300 compensates the bias power applied to the transistor 400 by using the compensation bias current and the compensation signal output from the temperature compensation circuit 100 and the characteristic compensation circuit 200, respectively. Can be improved and can always be operated with optimum operating characteristics.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, Various changes and modifications will be possible.

1. Bias control device
100. Temperature compensation circuit 110. Temperature detector
120. Reference voltage generator 130. Converter
140. Current control unit 200. Characteristic compensation circuit
220. Character comparison unit 240. Feedback control unit
260. Current mirror 300. Bias compensation circuit

Claims (7)

delete delete A temperature compensation circuit generating a digital signal corresponding to the temperature of the transistor and outputting a compensation bias current obtained by adding or subtracting a control current to a reference bias current using the generated digital signal;
A characteristic compensation circuit which detects a characteristic error of a mirror transistor connected in parallel with the transistor and outputs a compensation signal for compensating the characteristic error; And
A bias compensation circuit for compensating and outputting a bias power applied to a control terminal of the transistor by using the compensation bias current and the compensation signal;
Including;
The characteristic error is an error according to at least one of the deviation of the transconductance and the threshold voltage of the mirror transistor,
Wherein the temperature compensation circuit comprises:
A temperature detector detecting a temperature voltage corresponding to the temperature;
A conversion unit converting the detected temperature voltage into a digital signal and generating the digital signal; And
And a current controller for outputting the compensation bias current by adding or subtracting the control current to the reference bias current according to the converted digital signal.
The current control unit includes:
A control signal output unit for outputting a temperature control signal using the generated digital signal;
A reference bias generator for controlling the reference bias current to flow; And
And a current controller connected in parallel with the reference bias generator and controlling to add or subtract the control current to the reference bias current according to the temperature control signal.
A temperature compensation circuit generating a digital signal corresponding to the temperature of the transistor and outputting a compensation bias current obtained by adding or subtracting a control current to a reference bias current using the generated digital signal;
A characteristic compensation circuit which detects a characteristic error of a mirror transistor connected in parallel with the transistor and outputs a compensation signal for compensating the characteristic error; And
A bias compensation circuit for compensating and outputting a bias power applied to a control terminal of the transistor by using the compensation bias current and the compensation signal;
Including;
The characteristic error is an error according to at least one of the deviation of the transconductance and the threshold voltage of the mirror transistor,
The characteristic compensation circuit,
And a characteristic comparison unit comparing the voltage according to the drain-source current of the mirror transistor with a second reference voltage which is previously set and detecting the characteristic error as a result of the comparison.
5. The method of claim 4,
The mirror transistor,
Is the same structure as the transistor,
A bias control device having a smaller size than the transistor.
5. The method of claim 4,
The mirror transistor,
And the transistor is 1 m in size.
5. The method of claim 4,
The transistor comprising:
A bias control device that is a power amplifier.

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