KR101478363B1 - Device and method for tuning oscillation frequency of wideband - Google Patents

Abstract

The present invention relates to a broadband oscillation frequency tuning device and a method thereof capable of quickly and accurately generating an oscillation frequency of a broadband channel having a wide output frequency even with a single voltage controlled oscillator (VCO) A voltage controlled oscillator for variably controlling an oscillation frequency according to at least one or more tuning data, and a controller for calculating an oscillation frequency output from the voltage controlled oscillator, and for adjusting the calculated oscillation frequency to a reference frequency of a pre- Determines the amplitude tuning data that causes the swing amplitude of the voltage-controlled oscillator to approach the reference amplitude in accordance with the result of comparing the output swing amplitude of the voltage-controlled oscillator with the reference amplitude, and outputs the determined tuning data as the determined coarse and amplitude tuning data Equipped with a digital tuning controller to control each voltage-controlled oscillator The.

PLL, VCO, Oscillation Frequency, Tuning, Kvco

Description

TECHNICAL FIELD [0001] The present invention relates to a broadband oscillation frequency tuning device, and more particularly,

The present invention relates to tuning of a broadband oscillation frequency, and more particularly, to a broadband oscillation frequency tuning device and method for quickly and accurately generating an oscillation frequency of a broadband channel having a wide output frequency even with a single voltage controlled oscillator (VCO).

In recent years, the phase locked loop (PLL) has been required to support a wideband and a multiband, and the frequency range of a voltage controlled oscillator (VCO) has also been widened.

Accordingly, a technology capable of having a constant Kvco in a wide band and a technique capable of performing a sufficient swing irrespective of a frequency range are required.

The voltage controlled oscillator (VCO) is a variable frequency oscillation circuit module which stably oscillates the local oscillation frequency by an applied voltage of a frequency synthesizer, and is used as one of the most important components of the frequency synthesizer circuit.

Currently, a CMOS type with a built-in LC resonator is mainly used for a high-frequency voltage-controlled oscillator. CMOS circuit technology is the most widely used technology because it has a small static consumption current, and since most of the semiconductor technology is settled by CMOS technology today, it is not only highly reliable in manufacturing process but also advantageous in high integration.

1 shows a circuit of a general voltage-controlled oscillator, which includes LC resonance units L and C, a negative-Gm unit 10 for supplying a current (the transistors are connected in a positive feedback and the output signal is inverted with respect to the input signal Circuit that appears).

When a voltage is applied to the voltage-controlled oscillator thus configured, the oscillator resonates at a constant frequency by the feedback circuit. The signal is weakened by the resistance component parasitic to the inductor L and the capacitor C. The oscillation circuit is a circuit which supplies the current again in the negative-Gm unit 10 and oscillates with a certain magnitude.

Here, when a transition is made from a used frequency to another frequency, the control voltage Vctrl applied to the middle of a plurality of varactors (Cvar1, Cvar2; Varactor) is varied to change the capacitance, .

However, in the case of the varactors Cvar1 and Cvar2, the tuning range is narrow and is used for fine tuning. However, if the voltage controlled oscillator used at 2 GHz is to be used at 4 GHz, varactors Cvar1 and Cvar2, The frequency range could not be changed.

For this reason, a plurality of voltage-controlled oscillators whose size is adjusted to cover the frequency of the current broadband are used, and a specific voltage-controlled oscillator among a plurality of voltage-controlled oscillators is selected and used according to the oscillation frequency to be output .

The use of a plurality of voltage-controlled oscillators as shown in FIG. 1 significantly increases the design area as well as a considerable burden from the viewpoint of manufacturing cost. Further, in the process of switching a plurality of voltage-controlled oscillators, So that the noise characteristic is deteriorated.

It is an object of the present invention to provide a broadband oscillation frequency tuning device and method capable of quickly and accurately generating an oscillation frequency of a broadband channel having a wide output frequency even with a single voltage controlled oscillator (VCO).

It is another object of the present invention to provide a broadband oscillation frequency tuning apparatus and method capable of always keeping the swing amplitude output from the voltage controlled oscillator constant regardless of the oscillation frequency.

According to an aspect of the present invention, there is provided a voltage controlled oscillator comprising: a voltage controlled oscillator for varying an oscillation frequency according to an input control voltage and at least one tuning data; A counter for counting the signal output from the voltage-controlled oscillator for a predetermined time; A coarse control unit for calculating an oscillation frequency using the count value input from the counter and controlling the voltage controlled oscillator with coarse tuning data so that the calculated oscillation frequency approaches a reference frequency of a previously selected channel; And a controller for determining amplitude tuning data for causing a swing amplitude of the voltage-controlled oscillator to approach a reference amplitude according to a result of comparing the output swing amplitude of the voltage-controlled oscillator with a reference amplitude, and controlling the voltage- And an amplitude control unit for controlling the amplitude control unit.

Specifically, the voltage-controlled oscillator includes a coarse tuning unit in which a plurality of tuning cells are connected in parallel between a first output terminal and a second output terminal, from which a differential signal is output, respectively, and the coarse tuning unit includes: And the capacitance is variable according to the coarse tuning data.

The tuning cell may include a plurality of capacitors connected to each other through a switch between a first output terminal and a second output terminal. The switch may be opened or closed in accordance with coarse tuning data of the coarse control unit to adjust a capacitance of the tuning cell And the capacitances of the tuning cells are set to be different from each other.

The voltage-controlled oscillator includes a plurality of tuning cells connected in parallel between a first output terminal and a second output terminal through which differential signals are output, and each tuning cell has an amplitude tuning section ; And an amplitude detector for detecting a swing amplitude of the differential signal input from the first output terminal and the second output terminal and for comparing the detected swing amplitude and the reference amplitude with each other.

Wherein the amplitude detector outputs data as a result of comparing the swing amplitude and the reference amplitude to the amplitude controller, wherein the amplitude controller controls the voltage controlled oscillator with preset initial value tuning data while the coarse controller is operating The tuning data of the initial value is a value that maximizes the swing amplitude of the voltage-controlled oscillator.

The tuning device controls the first and second control voltages to be sequentially applied to the voltage controlled oscillator, and as a result, the slope of the Kvco curve is calculated using the first and second oscillation frequencies obtained from the counter, And a Kvco control unit for controlling the voltage-controlled oscillator by selecting Kvco tuning data such that the slope approaches a preset slope.

전압이고, 제2 제어전압은 대략

전압인 것을 특징으로 한다.Wherein the Kvco curve is a gain curve of the oscillation frequency selected by the coarse tuning data of the coarse control unit,

Voltage, and the second control voltage is approximately

Voltage.

Wherein the voltage controlled oscillator includes a Kvco tuning unit in which a plurality of tuning cells are connected in parallel between a first output terminal and a second output terminal to which the differential signals are respectively output and wherein each tuning cell has a capacitance Wherein each of the tuning cells of the Kvco tuning unit includes a plurality of varactors connected between first and second output terminals, and a plurality of second varactors connected to the common node of the plurality of varactors according to Kvco tuning data, And a multiplexer for selectively inputting the multiplexed data.

According to another aspect of the present invention, there is provided a voltage controlled oscillator comprising: a voltage controlled oscillator for variably controlling an oscillation frequency according to an input control voltage and at least one tuning data; A counter for counting the signal output from the voltage-controlled oscillator for a predetermined time; A coarse control unit for calculating an oscillation frequency using the count value input from the counter and controlling the voltage controlled oscillator with coarse tuning data so that the calculated oscillation frequency approaches a reference frequency of a previously selected channel; And controlling the first and second control voltages to be sequentially applied to the voltage controlled oscillator. The slope of the Kvco curve is calculated using the first and second oscillation frequencies obtained from the counter, And a Kvco control unit for controlling the voltage controlled oscillator by selecting Kvco tuning data to be close to the set slope.

According to an aspect of the present invention, there is provided a method for controlling a tuning device, the method comprising: controlling a tuning data to vary an oscillation frequency of a voltage-controlled oscillator to a predetermined initial value when a channel selection command is input; A second step of calculating an oscillation frequency output from the voltage controlled oscillator according to the initialized tuning data and comparing the oscillation frequency with a reference frequency of a previously selected channel; And a third step of determining coarse tuning data having a Kvco curve whose oscillation frequency is close to a reference frequency according to the comparison result, and controlling a capacitance of the voltage controlled oscillator with the determined tuning data.

Wherein the tuning data includes: coarse tuning data for adjusting a capacitance of a voltage-controlled oscillator such that an oscillation frequency of the voltage-controlled oscillator has a Kvco curve approximating a reference frequency of a selected channel; And Kvco tuning data for adjusting the capacitance of the voltage-controlled oscillator such that the swing amplitude of the oscillation frequency is close to the set reference amplitude, and amplitude tuning data for adjusting the resistance of the voltage-controlled oscillator .

전압을 인가하는 단계; 상기 인가된 전압에 따라 전압제어발진기에서 출력된 주파수를 카운트하여 발진주파수를 계산하는 단계; 및 상기 계산된 발진주파수와 선택된 채널에 대한 기준주파수를 상호 비교하는 단계;를 포함하는 것을 특징으로 한다.Wherein the second step comprises:

Applying a voltage; Counting a frequency output from the voltage-controlled oscillator according to the applied voltage and calculating an oscillation frequency; And comparing the calculated oscillation frequency with a reference frequency for the selected channel.

A fourth step of sequentially applying the first and second control voltages to the voltage-controlled oscillator after the third step and calculating the first and second oscillation frequencies sequentially output from the voltage-controlled oscillator, ; And a fifth step of calculating the slope of the Kvco curve using the calculated first and second oscillation frequencies and then controlling the capacitance of the voltage-controlled oscillator by selecting Kvco tuning data such that the calculated slope approaches a preset slope ; ≪ / RTI >

A sixth step of applying a preset control voltage to the voltage-controlled oscillator after performing the fifth step; And an amplitude tuning data determining a swing amplitude of the voltage-controlled oscillator to be close to a reference amplitude according to a result of comparing the swing amplitude and the reference amplitude of the differential signal output from the voltage-controlled oscillator, And a seventh step of controlling the resistance of the oscillator.

As described above, according to the present invention, when a PLL applicable to a wideband and a multiband is designed, a single voltage-controlled oscillator can reduce power consumption by making it possible to tune a broadband oscillation frequency with a single voltage controlled oscillator (VCO) It also has the advantage of reducing the size of the PLL.

Further, there is an advantage that the reliability of the oscillation signal and the noise characteristic can be improved by keeping the swing amplitude constant regardless of the oscillation frequency of the voltage-controlled oscillator.

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

2 is a circuit block diagram of an oscillation frequency tuning apparatus according to the present invention, which includes a voltage controlled oscillator 100 (VCO), a prescaler 210, a PFD 230 (Phase Frequency Detector), a charge pump 250 A loop filter 270, a selection means 290, and a digital tuning controller 300. The digital tuning controller 300 includes a tuning controller 300,

The voltage-controlled oscillator 100 is configured to oscillate a local signal having a specific frequency according to an input control voltage.

The prescaler 210 includes a counter 211 and a frequency divider 215. The counter 211 is configured to count an output frequency generated by the voltage controlled oscillator 100 during a coarse tuning for a predetermined period of time The divider 215 divides the output frequency inputted from the voltage controlled oscillator 100 by an appropriate ratio and varies the dividing ratio according to the channel information on the dividing ratio input from the outside, And is configured to vary the oscillation frequency.

The PFD 230 compares the reference frequency input from the outside with the frequency inputted from the frequency divider 215 and outputs a pulse string corresponding to the difference.

The charge pump 250 is configured to vary the current according to the sign and the pulse width of the pulse train input from the PFD 230.

The loop filter 270 includes a band-pass filter (BPF) that filters various noise frequencies occurring during a loop operation and varies the output voltage through a change in the amount of charge accumulated using a capacitor.

The selecting means 290 selects and operates according to the control signal Coarselock of the digital tuning controller 300 during the tuning of the oscillation frequency of the voltage controlled oscillator 100 so as not to output the output voltage of the loop filter 270, To be applied to the voltage-controlled oscillator 100. The voltage-

The digital tuning controller 300 controls a detailed circuit of the voltage-controlled oscillator 100 when a channel selection command is inputted from the outside to perform a coarse tuning for selecting a frequency having a Kvco curve as close as possible to a desired oscillation frequency, And when the coarse tuning is completed, the oscillation frequency of the voltage-controlled oscillator 100 is finely tuned through the frequency division ratio control of the frequency divider 215. [ The digital tuning controller 300 includes a coarse control unit 330, a Kvco control unit 350 and an amplitude control unit 370. The detailed configuration of the digital tuning controller 300 will be described later with reference to FIG.

In this manner, oscillation consisting of a phase locked loop (PLL) and a digital tuning controller 300 including the voltage controlled oscillator 100, the frequency divider 215, the PFD 230, the charge pump 250 and the loop filter 270, The frequency tuning device performs two operations, that is, coarse tuning and fine tuning, in order to tune the oscillation frequency at the time of channel tuning. The coarse tuning is subdivided into a first coarse tuning, a Kvco tuning, an amplitude tuning, and a second coarse tuning.

First, the digital tuning controller 300 performs coarse tuning when a channel selection command is input from the outside. The tuning controller 300 outputs a control signal Vctrl_con to the voltage generator 280. The voltage generator 280 generates a predetermined voltage by the selector 290 and outputs the selected voltage to the selector 290 The selector 290 switches the voltage input from the voltage generator 280 according to a control signal inputted from the digital tuning controller 300 and transmits the voltage to the voltage controlled oscillator 100 . For example, the selection unit 290 selects a signal input from the voltage generation unit 280 and transmits the signal to the voltage controlled oscillator 100 while the control signal Coarselock is '0'.

In a state where the input voltage generated by the voltage generator 280 is supplied to the voltage controlled oscillator 100, the digital tuning controller 300 selects a Kvco curve closest to the desired oscillation frequency and a capacitance value having a slope And when the appropriate capacitance value is selected, the output swing amplitude of the voltage-controlled oscillator 100 is controlled so as to be output at the set amplitude, and then the coars tuning is changed to '1' by the selecting means 290 .

When the coarse tuning is completed as described above, the digital tuning controller 300 outputs a control signal related to the frequency division ratio mapped to the selected channel information in the frequency divider 215 of the prescaler 210, The oscillation frequency can be finely tuned to a desired oscillation frequency by a capacitance value selected in the coarse tuning using a PLL loop composed of a charge pump 250, a charge pump 250, a loop filter 270 and a voltage controlled oscillator 100 .

Since the process of fine tuning through the PLL loop is a general method, a detailed process of coarse tuning will be described with the coarse tuning as the center.

3 is a conceptual diagram illustrating the configuration of a voltage-controlled oscillator according to the present invention. The voltage-controlled oscillator 100 includes LC resonators L and C, a negative-Gm unit 101 and an amplitude tuning unit 150 consist of.

The oscillation frequency of the voltage-controlled oscillator 100 increases as the input control voltage Vctrl increases. This is because of the capacitance characteristics of the varactors Cvar1 and Cvar2 provided in the negative-Gm unit 101 shown in Fig. 3, and a high voltage close to the high potential Vdd is applied to the inputs of the varactors Cvar1 and Cvar2 The capacitance of the varactors Cvar1 and Cvar2 decreases and the oscillation frequency rises. When a low voltage close to the low potential GND is applied to the inputs of the varactors Cvar1 and Cvar2, the capacitances of the varactors Cvar1 and Cvar2 become This is because the larger oscillation frequency is lowered. Therefore, the oscillation frequency outputted to the first output terminal (Vout +) and the second output terminal (Vout-) can be adjusted by adjusting the control voltage (vctrl) applied to the voltage controlled oscillator (100).

The LC resonance unit includes an inductor L and a capacitor C that are provided in parallel between the first output terminal Vout + and the second output terminal Vout-.

The negative-Gm unit 101 includes differential transistors, a Kvco tuning unit 110, and a coarse tuning unit 130.

The differential transistors PM1 and PM2 are PMOS transistors and NM1 and NM2 are NMOS transistors. The differential transistors PM1 and PM2 are NM1 and NM2, respectively. Cross-coupled.

The sources of the first differential transistors PM1 and PM2 are commonly coupled to the high potential Vdd. The drain of the PMOS transistor PM1 and the gate of the PMOS transistor PM2 are commonly connected to the first output terminal Vout + and the drain of the PMOS transistor PM2 and the gate of the PMOS transistor PM1 are coupled to the second output terminal Vout- .

The sources of the second differential transistors NM1 and NM2 are commonly coupled to the low potential Vss. The drain of the NMOS transistor NM1 and the gate of the NMOS transistor NM2 are commonly connected to the first output terminal Vout + and the drain of the NMOS transistor NM2 is connected to the second output terminal Vout- .

The first varactor Cvar1 is connected between the first output terminal Vout + and the control terminal CNd, and the second varactor Cvar1 is connected between the first output terminal Vout + The loop filter 270 or the voltage generating unit 280 is connected to the control terminal CNd through the selecting unit 290. The control unit CNd is connected between the control terminal CNd and the second output terminal Vout- And the control voltage Vctrl is input from the control voltage Vctrl. Although only the first and second varactors Cvar1 and Cvar2 are illustrated in FIG. 3, a plurality of varactors different from the first and second varactors Cvar1 and Cvar2 are connected to the first output terminal Vout + And further connected in parallel between the output terminals Vout-. The plurality of varactors are selectively operated by receiving the tuning data (Vcaps [N: 0]) from the digital tuning controller 300.

The first variable capacitor Cv1 is conceptually connected between the first output terminal Vout + and the low potential Vss, and the first variable capacitor Cv1 is connected to the first output terminal Vout + The second variable capacitor Cv2 is conceptually connected between the second output terminal Vout- and the low potential Vss. Although only the first and second variable capacitors Cv1 and Cv2 are illustrated in FIG. 3, a plurality of variable capacitors different from the first and second variable capacitors Cv1 and Cv2 are connected to the first output terminal Vout + Output terminals Vout-, and the plurality of variable capacitors are selectively operated by receiving the tuning data Fcaps [N: 0] from the digital tuning controller 300.

The amplitude tuning unit 150 conceptually includes a plurality of variable resistors Rv1 and Rv2 and an amplitude detector 160. The plurality of variable resistors Rv1 and Rv2 are connected to the first output terminal Vout + And the second output terminal (Vout-). The plurality of variable resistors Rv1 and Rv2 are selectively operated by receiving the tuning data Vampt [N: 0] from the digital tuning controller 300. The amplitude detector 160 receives the differential signals Vout + and Vout- output through the first and second output terminals Vout + and Vout-, detects the maximum swing amplitude of the differential signal, And transmits an amplitude up / down signal (Vampt_updown) according to the comparison result to the digital tuning controller (300) in comparison with the amplitude reference voltage (Vampt_ref).

4 is a detailed block diagram of a digital tuning controller according to the present invention. The digital tuning controller 300 includes a tuning controller 310, a coarse controller 330, a Kvco controller 350, and an amplitude controller 370).

The tuning control unit 310 generates an enable signal to the coarse control unit 330, the Kvco control unit 350 and the amplitude control unit 370 according to a preset tuning sequence when an external channel selection command is input, and performs coarse tuning, Kvco tuning, The amplitude tuning is controlled to be performed sequentially.

전압을 인가하고, 전압제어발진기(100)는 선택수단(290)으로부터 인가되는 제어전압(

)에 따른 주파수를 생성하게 된다.The coarse control unit 330 is for selecting a frequency having a Kvco curve closest to a desired oscillation frequency and counts (CNT [M: 0]) from a counter 211 for counting the frequency output from the voltage controlled oscillator 100. [ Value. At this time, the voltage generator 280 generates the voltage Vctrl_con according to the control signal Vctrl_con of the coarse controller 330

And the voltage-controlled oscillator 100 applies a control voltage (for example,

). ≪ / RTI >

The coarse control unit 330 sets the count value CNT [M: 0] delivered to the counter 211 of the prescaler 210 by the enable signal CNT_enable for a predetermined time, ), The coarse control unit 330 can predict the oscillation frequency of the voltage-controlled oscillator 100. In this case, Therefore, when the reference count value for each channel is stored in advance in the form of a map table, the coarse control unit 330 stores the count value CNT [M: 0] input from the counter 211 and the count value The reference count values are compared with each other to determine whether the oscillation frequency is higher or lower than the reference frequency. Accordingly, the coarse control unit 330 can automatically determine the tuning data (Fcaps [N: 0]) having the Kvco curve close to the desired oscillation frequency and adjust the capacitance of the coarse tuning unit 130 according to the determined tuning data .

During the coarse tuning, the Kvco control unit 350 and the amplitude control unit 370 operate with a preset default value. When the predetermined Kvco tuning and amplitude tuning are completed, the coarse control unit 330 selects (Coarselock = ' 1 ') for instructing fine tuning to the tuner 290.

When the coarse tuning is completed, the Kvco tuning is started by the Kvco controller 350. At this time, the coarse tuning data Fcaps [N: 0] is fixed to the determined value and the Kvco tuning data Vcaps [N: ]) And the amplitude tuning data (Vampt [N: 0]) are initialized to a fixed value.

전압과

전압이 각각 전압제어발진기(100)로 입력되도록 제어하게 되고, 각 인가 전압에 따라 전압제어발진기(100)에서 발진되는 주파수를 각각 계산하게 된다. 상기 계산된 각 발진주파수의 차이값을 이용하여 발진주파수의 기울기를 계산한 후 발진주파수의 기울기가 미리 설정된 기준기울기에 근접하도록 튜닝데이터(Vcaps[N:0])를 결정하게 된다. 한편, Kvco 곡선의 경우 저전위(Vss)와 고전위(Vdd) 구간 중 대략

전압과

전압 사이에서 리니어한 기울기를 갖는다.The Kvco control unit 350 controls (Vctrl_con) the voltage generation unit 280 to generate a plurality of voltages, for example, a control voltage Vctrl within a linear section of the Kvco curve,

Voltage and

The voltage is controlled to be input to the voltage-controlled oscillator 100, and the frequency oscillated by the voltage-controlled oscillator 100 is calculated according to each applied voltage. After calculating the slope of the oscillation frequency using the calculated difference value of the oscillation frequency, the tuning data (Vcaps [N: 0]) is determined so that the slope of the oscillation frequency approaches the preset reference slope. On the other hand, in the case of the Kvco curve, the low potential (Vss) and the high potential (Vdd)

Voltage and

And has a linear gradient between voltages.

The amplitude control unit 370 controls the amplitude tuning unit 150 to a preset initial value during the coarse tuning and the Kvco tuning, and then starts amplitude tuning in accordance with the enable signal of the tuning control unit 310. The amplitude tuning first monitors data (Vampt_updown) compared with the maximum amplitude (Vout +, Vout-) of the differential signals (Vout +, Vout-) oscillated by the voltage controlled oscillator 100 and the reference amplitude (Vampt_ref) The tuning data Vampt [N: 0] is determined in the direction of decreasing the amount of current of the amplitude tuning unit 150. When the maximum swing amplitude is lower than the reference amplitude, the amount of current of the amplitude tuning unit 150 (Vampt [N: 0]) in the direction of increasing the amplitude of the tuning signal.

Finally, the tuning control unit 310 controls the coarse control unit 330 to correct the occurrence of frequency shift while performing Kvco tuning and amplitude tuning on the selected Kvco curve at the time of coarse tuning, thereby controlling the coarse tuning once more And when the coarse tuning is completed, the dividing ratio signal for the selected channel is outputted in the frequency divider 215 of the prescaler 210 to perform the fine tuning.

Hereinafter, the detailed configuration and operation of the voltage-controlled oscillator 100 will be described with reference to FIGS. 5A through 7B.

5A shows a detailed configuration of the coarse tuning unit 130. The coarse tuning unit 130 includes tuning cells # 1 to #n between the first output terminal Vout + and the second output terminal Vout- #N).

The first tuning cell # 1 has a first capacitor Cv1, a first NMOS transistor NM1 and a second capacitor Cv2 connected in series between the first output terminal Vout + and the second output terminal Vout- It is connected. A plurality of inverters I1 and I2 are connected to the gate of the NMOS transistor NM1 in the first tuning cell # 1 to receive one bit of tuning data Fcaps from the digital tuning controller 300 It is configured to operate. The multi-stage tuning cells # 2 to #N have the same configuration as the first tuning cell # 1.

In addition, the multi-stage tuning cells (Tuning Cell # 1 to #N) are set to have different capacitances on a cell-by-cell basis. For example, if there are 10 tuning cells in multiple stages, the capacitors are configured so that the capacitance of each cell has a capacitance ratio of 1, 2, 3, 4, 6, 8, 10, 16, 32 and 64. This is achieved by adding a capacitance value for 3, 6, and 10 to a conventional binary array ( ²ⁿ (n is a natural number including 0)) and estimating the frequency by appropriately setting a wide frequency range without a blank So that it can be covered.

The NMOS transistor NM1 provided in the first tuning cell # 1 serves as a switch and is turned on or off by the tuning data Fcaps of the coarse control unit 330 and is supplied to the inverters I1 and I2 The plurality of resistors R1 and R2 connected in parallel can prevent the capacitors Cv1 and Cv2 from floating due to the common node Nd1 acting as the low potential Vss when the NMOS transistor NM1 is turned off have.

전압일 때를 기준으로 설정된 것이다. As shown in FIG. 5A, a coarse tuning unit 130 including a plurality of tuning cells is added to the negative-Gm unit 101 to generate a plurality of Kvco curves as shown in FIG. 5B at a wide band. Here, the slope of the linear part of the curve is called 'Kvco' or 'VCO gain'. Of course, the Kvco curve indicates that the control voltage vctrl input to the voltage controlled oscillator 100 is

Voltage is set as a reference.

5B is a graph showing a Kvco curve for each tuning data (Fcaps [4: 0]) input to the coarse tuning unit 130. FIG. That is, it is possible to vary the capacitances Cv1, Cv2, ... of the coarse tuning unit 130 to form several Kvco curves. The interval of the Kvco curve that allows all frequencies to be selected in the broadband can be adjusted using the capacitance of the internal capacitors Cv1, Cv2, ..., as shown in Fig. 5a.

In the thus configured coarse tuning unit 130, the capacitance of each tuning cell is changed by the tuning data (Fcaps [4: 0]) of the coarse control unit 330, It becomes possible to generate a frequency having a near Kvco curve.

Such a coarse tuning can solve the problem that the Kvco becomes too large in the wideband voltage-controlled oscillator 100 and the noise characteristic is deteriorated. For example, if a voltage-controlled oscillator 100 having a frequency range of 2 GHz to 4 GHz is required to be tuned only for coarse tuning, there is actually a large difference between the capacitance operating at 2 GHz and the capacitance operating at 4 GHz.

3, the amount of change in the capacitance of the negative-Gm unit 101 with respect to the plurality of varactors Cvar1 and Cvar2 by the control voltage vctrl is constant, while the voltage-controlled oscillator 100 varies in accordance with each oscillation frequency The difference in the amount of the total capacitance is 2 kHz and 4 GHz in Kvco. The Kvco value belonging to the frequency in the 4 GHz band having the value of F000 [N: 0], which is the tuning data Fcaps [N: 0], is set to Kvco in the frequency band of 2 GHz band when Fcaps [N: 0] is 11111 It has a large value.

If the value of Kvco is not constant within the tuning frequency range in the case of the wide band as in this case, the noise characteristic is deteriorated in the channel that deviates from the value of Kvco used when constructing the RC filter in the loop filter 270. Therefore, it is preferable to design the capacitance of the varactors Cvar1 and Cvar2 as the Kvco tuning unit 110 as shown in the following FIG. 6A so that the Kvco can maintain a constant maximum value in the entire region.

FIG. 6A shows a detailed configuration of the Kvco tuning unit 110 shown in FIG. 3. The slope of the Kvco curve selected during the coarse tuning process is suitably tuned through the Kvco tuning unit 110. FIG.

The Kvco tuning unit 110 includes a plurality of tuning cells (Tuning Cells # 1 to #N) between the first output terminal (Vout +) and the second output terminal (Vout-), each of which is a varactor that is a variable capacitance diode.

In the first tuning cell # 1, a plurality of varactors Cvar1 and Cvar2 are connected in series between the first output terminal Vout + and the second output terminal Vout-. A common node of the plurality of varactors Cvar1 and Cvar2 is switched in accordance with one bit of tuning data Vcaps output from the digital tuning controller 300 to generate a power supply voltage Vdd or a control voltage Vctrl To a common node of the varactors Cvar1 and Cvar2. The remaining tuning cells # 2 to #N have the same configuration as the first tuning cell # 1, but the tuning cells # 1 to #N receive different tuning data.

The multiplexer 111 of the Kvco tuning unit 110 receives the power supply voltage Vdd at high potential or the control voltage Vctrl input from the selecting means 290 according to the tuning data Vcaps input from the Kvco control unit 350, And supplies the control signals to the control terminals of the varactors Cvar1 and Cvar2 to control the capacitance of the Kvco tuning unit 110. [ The reason why the high voltage Vdd is selected and applied to the varactors Cvar1 and Cvar2 is that the high potential Vdd is applied to the common node of the varactors Cvar1 and Cvar2 due to the characteristics of the capacitors of the varactors Cvar1 and Cvar2, The varactors Cvar1 and Cvar2 are reliably turned off only when the voltage of the varactors Cvar1 and Cvar2 is applied. Also, the capacitance of the Kvco tuning unit 110 can be controlled by applying a control voltage to each of the tuning cells # 1 to #N according to the tuning data.

6B is a graph showing the result of changing the Kvco tuning data (Vcaps [N: 0]) while the tuning data of the coarse tuning unit 130 is fixed.

Here, Kvco tuning data (Vcaps [N: 0]) is represented by 4 bits (Vcaps [3: 0]) and it is shown that the slope of Kvco can be adjusted by controlling the voltage applied to four tuning cells. For example, '0000' as the tuning data (Vcaps [3: 0]) means that the capacitances are turned off as the high voltage Vdd input from the multiplexer is applied to the corresponding varactor in the sense that all the capacitances of the four tuning cells are turned off. Therefore, the curve with the tuning data '0000' has the maximum oscillation frequency with the lowest capacitance turned on, and the slope of the Kvco curve is most gentle as the influence of the capacitance of the varactor is small.

On the other hand, when the Kvco tuning data (Vcaps [3: 0]) is '1111', the capacitances of all varactors can be varied by the control voltage (Vctrl) while the capacitances of the four tuning cells are all turned on . Therefore, the frequency becomes the lowest with the capacitance of the varactor being the largest, and the capacitance of the varactor is greatly changed by the control voltage, so that the slope is the most rapid.

As described above, the capacitance of the Kvco tuning unit 110 is adjusted according to the tuning data Vcaps, and the frequency shifts slightly. The shifted frequency can be corrected by performing the further coarse tuning once more.

As described above, the noise characteristics can be improved by using the coarse tuning and the Kvco tuning as shown in FIGS. 5A and 6A. However, in the case of the voltage-controlled oscillator 100 having the tuning range of 2 GHz to 4 GHz according to the capability (current consumption) of the negative-Gm unit 101, the burden of the capacitance increases as the frequency goes down to the low frequency (2 GHz) The output swing amplitude of the control oscillator 100 becomes too small to lower the noise characteristic, and in the worst case, the oscillation can not be performed.

In order to overcome this concern, it is necessary to design the negative-Gm unit 101 so that a sufficient current flows therethrough. However, in order to cover the band of 2 GHz, the low-frequency band (4 GHz band) 2GHz band) is not good in terms of power consumption.

3, the conventional Negative-Gm unit 101 is configured to cover the frequency range with a minimum current, and then detects the swing output from the voltage-controlled oscillator 100, The amplitude tuning unit 150 is constructed.

3, the amplitude detector 160 detects the output swing of the voltage-controlled oscillator 100, compares the output swing with the reference amplitude, and transmits the data (Vampt_updown) of the comparison result to the digital tuning controller 300. The digital tuning controller 300 changes the amplitude tuning data Vampt [N: 0] according to the comparison result of the amplitude detector 160 to control the tuning cell of the amplitude tuning unit 150 on and off. When the tuning cell is turned on, the current of the negative-Gm unit 101 is increased, and the output swing of the voltage-controlled oscillator 100 can be increased.

FIG. 7A shows the tuning cell of the amplitude tuning unit 150, and FIG. 7B shows the configuration of the amplitude detector 160 of the amplitude tuning unit 150. FIG.

The amplitude tuning unit 150 includes multiple tuning cells # 1 to #N between the first output terminal Vout + and the second output terminal Vout-.

The structure of the first tuning cell # 1 has a structure in which the differential transistors PM11 and NM12 (NM11 and NM12) are cross-coupled together as in the differential transistor of the negative-Gm unit 101, Switches NM13 and NM14 are provided between the output terminals Vout1 and Vout2 and are configured to be turned on or off according to the tuning data Vampt of one bit transmitted from the digital tuning controller 300. [ The switches NM13 and NM14 are NMOS transistors. When the tuning data corresponding to the 'high' signal is input from the digital tuning controller 300, the switches NM13 and NM14 are turned on.

All the tuning cells have the same configuration as the first tuning cell # 1, and each of the tuning cells # 1 to #N receives the tuning data Vampt of one bit different from the first tuning cell # 1.

The amplitude detector 160 includes a swing detector 161, a low-pass filter 163, and a comparator 165, as shown in FIG. 7B.

The swing detecting unit 161 detects the maximum swing amplitude by using the differential signals Vout + and Vout- output from the voltage-controlled oscillator 100 as gate inputs of the NMOS transistors. The detected signal is filtered by a low frequency filter 163 (LPF), and the filtered DC component signal is filtered by a comparator 165 operated by a first bias (bias1) The amplitude comparison signal Vampt_ref is compared with the amplitude reference signal Vampt_ref to be output as the comparison result Vampt_down or Vampt_up.

Here, the amplitude tuning unit 150 sets the value of '1111', which is the initial value of the tuning data (Vampt [N: 0]), to be able to operate normally in a lower frequency band, It is desirable to give. This is because if the command to increase the swing (Vampt_up) from the amplitude detector 160 is inputted, the current tuning data can be set immediately because it is the maximum swing state that can be operated by the current voltage controlled oscillator 100, When the command for lowering the swing (Vampt_down) is inputted from the amplitude detector 160, the tuning data is determined in the direction of turning off the tuning cells one by one. In this process, the output signal of the amplitude detector 160 is changed to another value (Vampt_down ), It can be considered that the optimum value has been reached and the amplitude tuning can be completed. That is, if the initial value of the amplitude tuning is set to a value that turns on all the amplitude tuning cells instead of the intermediate value, the access to the optimum value is quick and the control is simple, which is preferable.

8A to 8E are flowcharts showing an overall tuning process of an oscillation frequency according to an embodiment of the present invention, and will be described with reference to FIGS. 2 to 7B.

First, the digital tuning controller 300 determines whether a command for selecting or switching a predetermined channel has been transmitted from a microcomputer or the like receiving a user's remote control signal (S1). If no channel selection or channel switching command is input, the digital tuning controller 300 controls the voltage controlled oscillator 100, the frequency divider 215, and the like so that the voltage controlled oscillator 100 holds and maintains the current oscillation frequency (S2).

If a predetermined channel selection command is input, the digital tuning controller 300 sets tuning data (Fcaps, Vcaps, and Vampt) input to the tuning units 110, 130, and 150 of the voltage controlled oscillator 100 in advance And controls the capacitors and the resistors of the Kvco tuning unit 110, the coarse tuning unit 130 and the amplitude tuning unit 150 of the voltage controlled oscillator 100 using the initialized tuning data ). In the case of the initial values of the coarse tuning and the Kvco tuning (Fcaps and Vcaps), taking an intermediate value in the control range is advantageous because it is possible to quickly obtain a desired oscillation frequency in any channel. For example, if the tuning data can have a value ranging from '0000' to '1111' of 4 bits, it is preferable to set a value of approximately '1000' which is a middle value of the control range as a default value.

After controlling the voltage-controlled oscillator 100 to a predetermined initial value as described above, the voltage-controlled oscillator 100 performs first coarse tuning and Kvco tuning, amplitude tuning, and amplitude tuning in order to accurately output the oscillation frequency for the selected channel. The coarse tuning process using the two-coarse tuning and the fine tuning process using the frequency divider 215 are sequentially performed.

Further, in the present invention, not only the first coarse tuning, the Kvco tuning, the amplitude tuning, and the second coarse tuning are performed, but only a part of the tuning process is performed to perform some desired purposes to some extent. For example, the tuning system may be configured to either seek a desired oscillation frequency using first coarse tuning and fine tuning, or seek a desired oscillation frequency using first coarse tuning and Kvco tuning and fine tuning, Tuning and fine tuning may be used to find the desired oscillation frequency, or may be configured to seek the desired oscillation frequency using first coarse tuning and Kvco tuning, amplitude tuning, and fine tuning.

However, the following description will be made based on the most preferred embodiment of the present invention.

■ 1st coarse tuning

전압이 전압제어발진기(100)의 버랙터로 공급되도록 한다. The tuning controller 310 of the digital tuning controller 300 transmits an enable signal to the coarse controller 330 to perform the first coarse tuning process. Accordingly, the coarse control unit 330 outputs a control signal (coarselock) to the selection unit 290 so that the output of the voltage generation unit 280 is supplied to the voltage controlled oscillator 100, not the output of the loop filter 270 (S11). In this state, the coarse control unit 330 outputs the control signal Vctrl_con to the voltage generating unit 280,

So that the voltage is supplied to the varactor of the voltage-controlled oscillator 100.

)과 상기에서 초기화된 튜닝데이터(Fcaps, Vcaps 및 Vampt)에 따라 소정의 주파수를 갖는 신호를 발진하게 된다.Accordingly, the voltage-controlled oscillator 100 outputs a control voltage ("

) And the tuning data (Fcaps, Vcaps, and Vampt) initialized in the above.

The coarse control unit 330 outputs an enable signal to the counter 211 of the prescaler 210. The counter 211 counts the oscillation frequency output from the voltage controlled oscillator 100 for a predetermined time, (330). Accordingly, the coarse controller 330 calculates the oscillation frequency using the counted value for a predetermined time, compares the calculated oscillation frequency with the reference frequency for the selected channel, and determines whether the oscillation frequency is close to the reference frequency (S12 to S14).

If the oscillation frequency is greater than the desired reference frequency in step S15, the coarse control unit 330 selects the tuning data Fcaps [N: 0] in the direction of lowering the oscillation frequency, 130) (S16). In the coarse tuning unit 130, when the transistor serving as a switch of each tuning cell is turned on according to the tuning data, the capacitor is turned on, so that the capacitance of the coarse tuning unit 130 also increases. .

If the oscillation frequency is smaller than the desired reference frequency, the coarse control unit 330 selects the tuning data Fcaps [N: 0] in the direction of increasing the oscillation frequency and outputs the tuned data to each tuning cell of the coarse tuning unit 130 (S17). In the coarse tuning unit 130, when the transistor serving as a switch is turned off according to the tuning data, the capacitor is turned off. Therefore, the capacitance of the coarse tuning unit 130 also decreases, and the oscillation frequency of the voltage controlled oscillator 100 increases.

The coarse tuning unit 130 outputs an enable signal to the counter 211 of the prescaler 210 and the counter 211 counts the oscillation frequency output from the voltage controlled oscillator 100 for a predetermined time To the coarse control unit 330. The coarse control unit 330 calculates the oscillation frequency using the count value transmitted and compares the calculated oscillation frequency with the reference frequency for the selected channel to determine again whether the oscillation frequency is close to the reference frequency (S12 To S14).

If the oscillation frequency is the closest to the reference frequency, the coarse control unit 330 fixedly controls the coarse tuning unit 130 with the coarse tuning data having the current Kvco curve, and outputs the first coarse tuning completion signal to the tuning control unit (Step S18). That is, the first coarse tuning is a process of selecting a Kvco curve closest to a desired frequency among a plurality of Kvco curves within a certain frequency range as shown in FIG. 5B. In FIG. 5B, although a plurality of Kvco curves are shown as straight lines for convenience, they are actually drawn as curves instead of straight lines, and the intervals and the slopes of the Kvco curves are different from each other according to the frequency band.

■ Kvco tuning

전압이 전압제어발진기(100)의 버랙터로 공급되도록 제어하게 된다(S21). 여기서 Kcvo 튜닝 과정은 상기 제1 코오스 튜닝 과정에서 선택된 Kvco 곡선의 기울기를 알고, 그 기울기를 조정하기 위한 과정이다. 기울기를 계산하기 위해서는 Kvco 곡선 중 리니어(linear)한 구간을 체크하여야 하는 데, 리니어한 구간은 저전위(Vss)와 고전위(Vdd) 중 대략

부터

구간 사이에서 나타난다. 이에 따라 전압제어발진기(100)의 버랙터로

전압을 인가하는 것이다. 물론, 설계에 따라 인가전압 레벨은 다소 변경될 수 있다.The tuning control unit 310 then transmits an enable signal to the Kvco control unit 350 to start Kvco tuning. Accordingly, the Kvco control unit 350 controls the voltage generation unit 280 (Vctrl_con)

So that the voltage is supplied to the varactor of the voltage-controlled oscillator 100 (S21). Here, the Kcvo tuning process is a process for knowing the slope of the Kvco curve selected in the first coarse tuning process and adjusting the slope thereof. In order to calculate the slope, a linear section of the Kvco curve must be checked. The linear section has a roughly one of a low potential (Vss) and a high potential (Vdd)

from

It appears between intervals. Accordingly, as the varactor of the voltage-controlled oscillator 100

Voltage is applied. Of course, depending on the design, the applied voltage level can be changed somewhat.

Accordingly, the voltage-controlled oscillator 100 oscillates a signal having a predetermined frequency according to the set tuning data. Here, the coarse tuning unit 130 is set to the tuning data (Fcaps [N: 0]) determined in the first coarse tuning process, but the tuning data Vcaps [N: 0] of the Kvco tuning unit 110 and the amplitude tuning unit 150 N: 0] and Vampt [N: 0]) are still set to initial values.

The Kvco control unit 350 outputs an enable signal to the counter 211 of the prescaler 210. The counter 211 counts the oscillation frequency output from the voltage controlled oscillator 100 for a predetermined period of time, 350). Accordingly, the Kvco control unit 350 calculates the oscillation frequency using the counted value during the set time, and temporarily stores the calculated first oscillation frequency (S22).

전압이 전압제어발진기(100)의 버랙터로 공급되도록 제어하게 된다(S23).Then, the Kvco control unit 350 controls the voltage generation unit 280 (Vctrl_con)

So that the voltage is supplied to the varactor of the voltage-controlled oscillator 100 (S23).

Accordingly, the voltage-controlled oscillator 100 oscillates a signal having a predetermined frequency according to the set tuning data.

The Kvco control unit 350 outputs an enable signal to the counter 211 of the prescaler 210. The counter 211 counts the oscillation frequency output from the voltage controlled oscillator 100 for a predetermined time and outputs the counted oscillation frequency to the Kvco control unit 350 ). Accordingly, the Kvco control unit 350 calculates the oscillation frequency using the counted value for a predetermined time, and temporarily stores the calculated second oscillation frequency (S24).

,

)의 차이값과 저장된 제1 및 제2 발진주파수의 차이를 이용하여 제1 코오스 튜닝 과정에서 선택된 Kvco 곡선의 기울기를 계산하고, 계산된 기울기와 미리 설정된 기준기울기를 상호 비교하게 된다(S25). Then, the Kvco control unit 350 controls the control voltage applied to the voltage controlled oscillator 100

,

) And the difference between the stored first and second oscillation frequencies, the slope of the Kvco curve selected in the first coarse tuning process is calculated, and the calculated slope and the preset reference slope are compared with each other (S25).

If the slope calculated from the comparison result is larger than the desired slope (S27), the Kvco controller 350 selects the tuning data (Vcaps [N: 0]) in a direction of gently lowering the slope of the Kvco curve 6a to the respective tuning cells of the Kvco tuning unit 110 (S28). That is, according to the tuning data, when the power supplied to the varactor is different, when the tuning data is '0', the Vdd voltage is applied to the varactor so that the capacitance is turned off and the oscillation frequency becomes higher as shown in FIG. It will be canceled. Accordingly, the Kvco control unit 350 selects '1000' as the tuning data (Vcaps [N: 0]) when the initial value is '1100', and applies the selected tuning data to the Kvco tuning unit 110 .

If the slope calculated above is smaller than the desired reference slope, the Kvco controller 350 selects the tuning data (Vcaps [N: 0]) in the direction of increasing the slope of the Kvco curve to some extent, To the respective tuning cells of the tuner 110 (S29). That is, when the tuning data is '1', the control voltage is applied to the varactor, the capacitance is turned on, and the oscillation frequency is lowered as shown in FIG. Therefore, the Kvco control unit 350 selects the tuning data (Vcaps [N: 0]) as '1110' when the initial value is '1100', for example, and sets the selected tuning data to each tuning cell of the Kvco tuning unit 110 .

전압과

전압을 순차적으로 공급하고, 각 발진주파수의 차이를 이용하여 기울기를 계산하고, 계산된 기울기와 기준기울기를 상호 비교하게 된다.In this way, the tuning data is changed from the initial value to the direction of lowering or heightening the slope of the Kvco curve, and then the slope of the Kvco curve of the signal oscillated according to the tuning data is checked (S21 to S26). That is, the Kvco control unit 350 controls the voltage controlled oscillator 100

Voltage and

Voltage is sequentially supplied, the slope is calculated using the difference between the oscillation frequencies, and the calculated slope and the reference slope are compared with each other.

If the calculated slope is the closest to the reference slope (S26), the Kvco control unit 350 performs the fixed control of the Kvco tuning unit 110 with Kvco tuning data having the current slope, and tunes the Kvco tuning completion signal To the control unit 310 (S30). That is, the Kvco tuning is a process of checking the slope of the Kvco curve selected in the first coarse tuning and adjusting the slope of the Kvco curve so as to approach the reference slope as shown in FIG. 6b. In FIG. 6B, although a plurality of Kvco curves are shown as straight lines at regular intervals for convenience, they are actually curved lines instead of straight lines.

■ Amplitude Tuning

전압이 전압제어발진기(100)의 버랙터로 공급되도록 제어하게 된다(S31). 여기서 진폭 튜닝 과정은 전압제어발진기(100)의 출력 스윙을 원하는 진폭으로 조정하기 위한 과정이다. The tuning control unit 310 then transmits an enable signal to the amplitude control unit 370 to start amplitude tuning. Accordingly, the amplitude controller 370 controls the voltage generator 280 (Vctrl_con)

So that the voltage is supplied to the varactor of the voltage-controlled oscillator 100 (S31). Here, the amplitude tuning process is a process for adjusting the output swing of the voltage-controlled oscillator 100 to a desired amplitude.

7B, the amplitude detector 160 receives the differential signals Vout + and Vout- output from the voltage-controlled oscillator 100, detects the maximum swing amplitude of the differential signal (S32) Signal to a desired amplitude reference voltage Vampt_ref and transmits a high signal Vampt_down or a low signal Vampt_up to the amplitude controller 370 according to the comparison result at step S33.

The amplitude controller 370 determines whether the amplitude of the detected oscillation frequency is close to the reference amplitude (S34). If the detected amplitude is larger than the reference amplitude (S35), the amplitude controller (370) (Vampt [N: 0]) in a direction to lower the amplitude of the oscillation frequency of the voltage-controlled oscillator 100 and outputs the selected tuning data to each tuning cell of the amplitude tuning unit 150 shown in FIG. 7A (S36). That is, the swing amplitude varies according to the tuning data. When the tuning data is '0', the transistor is turned off to increase the resistance, thereby reducing the swing amplitude. Accordingly, the amplitude controller 370 selects '1110' as the tuning data (Vampt [N: 0]) when the initial value is, for example, '1111', and outputs the selected tuning data to each tuning cell of the amplitude tuning unit 150 .

If the detected amplitude is smaller than the reference amplitude, the amplitude controller 370 selects the tuning data Vampt [N: 0] in a direction that slightly increases the swing amplitude of the voltage controlled oscillator 100, (Step S37). Here, when the tuning data is '1', the transistor is turned on to increase the swing amplitude as the amount of output current increases. Accordingly, the amplitude controller 370 selects '1110' as the tuning data (Vampt [N: 0]) and applies the selected tuning data to the amplitude tuning unit 150 when the initial value is '1100' .

If the detected swing amplitude is close to the reference amplitude (S34), the amplitude tuning unit 150 is fixedly controlled by the amplitude tuning data having the current amplitude, and the amplitude tuning completion signal is transmitted to the tuning control unit 310 (S38). In this case, the amplitude tuning unit 150 preferably sets the initial value to a value at which the swing amplitude becomes maximum. In this case, the amplitude tuning unit 150 operates only in the direction of maintaining or lowering the swing amplitude, and thus the control is quick and convenient. That is, the amplitude controller 370 can control the swing amplitude to be optimized when the signal (Vampt_updown) output from the amplitude detector 160 is changed ('low' -> high).

■ 2nd coarse tuning

In this manner, first coarse tuning, Kvco tuning, and amplitude tuning are performed. However, the frequency of the Kvco curve selected in the first coarse tuning process can be slightly shifted through the above Kvco tuning and amplitude tuning processes. Accordingly, it is necessary to perform the same processes (S11 to S18) as in the first coarse tuning once more.

Accordingly, the tuning control unit 310 outputs the coarse tuning enable signal to the coarse control unit 330 again. Accordingly, the coarse controller 330 performs the first coarse tuning process again to correct the frequency-shifted Kvco curve to the original frequency band (S41, S42).

When the second coarse tuning is completed, the coarse control unit 330 outputs a control signal (coarselock) to the selecting unit 290 so that the output signal of the loop filter 270, not the output signal of the voltage generating unit 280, Controlled oscillator 100 and transmits the second coarse tuning completion signal to the tuning control unit 310 at step S43.

■ Fine Tuning

The tuning control unit 310 determines that all the coarse tunings have been completed and outputs frequency division ratio data for the selected channel in the frequency divider 215 of the prescaler 210 and outputs the frequency division data to the frequency divider 215 and the PFD 230, The micro-tuning is performed through the loop of the pump 250, the loop filter 270, and the voltage-controlled oscillator 100 (S51).

When such fine tuning is performed, the voltage-controlled oscillator 100 accurately outputs a desired oscillation frequency for the selected channel. The detailed process of such fine tuning is a general method, and a detailed description thereof will be omitted.

The above-described embodiment of the present invention discloses the most preferable case for the purpose of illustration, and actually, only a part of the tuning process may be selected and performed in the coarse tuning process. For example, the tuning system may be configured to either seek a desired oscillation frequency using first coarse tuning and fine tuning, or seek a desired oscillation frequency using first coarse tuning and Kvco tuning and fine tuning, Tuning and fine tuning may be used to find the desired oscillation frequency, or may be configured to seek the desired oscillation frequency using first coarse tuning and Kvco tuning, amplitude tuning, and fine tuning.

It is apparent that the configurations of the voltage-controlled oscillator and the digital tuning controller can be appropriately changed according to the control method according to various embodiments as described above. Therefore, such modifications, alterations, and additions should be defined by the claims appended hereto, as well as the appended claims.

1 is a circuit diagram of a general voltage controlled oscillator.

2 is a circuit block diagram showing an oscillation frequency tuning apparatus according to the present invention.

3 is a conceptual diagram showing a configuration of a voltage-controlled oscillator according to the present invention.

4 is a block diagram showing a detailed circuit of the digital tuning controller according to the present invention.

5A is a circuit diagram showing the detailed configuration of the coarse tuning unit of FIG.

5B is a graph showing a Kvco curve for each tuning data input to the coarse tuning unit.

6A is a circuit diagram showing a tuning cell of the Kvco tuning section of FIG.

6B is a graph showing a result of changing Kvco tuning data while the tuning data of the coarse tuning section is fixed

7A is a circuit diagram showing a tuning cell of the amplitude tuning unit of FIG.

FIG. 7B is a circuit diagram showing the configuration of the amplitude detector of the amplitude tuning section of FIG. 3; FIG.

8A to 8E are flow charts showing an overall tuning process of an oscillation frequency according to an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

100: voltage controlled oscillator (VCO) 101: negative-Gm unit

110: Kvco tuning unit 130: coarse tuning unit

150: amplitude tuning unit 160: amplitude detector

210: prescaler 211: counter

215: Frequency divider 230: PFD (Phase Frequency Detector)

250: Charge pump 270: Loop filter

280: voltage generator 290: selection means

300: Digital tuning controller 310: Tuning control part

330: Coose control unit 350: Kvco control unit

370: amplitude controller

Claims (29)

A voltage-controlled oscillator for variably controlling an oscillation frequency according to an input control voltage and at least one tuning data; A counter for counting the signal output from the voltage-controlled oscillator for a predetermined time; A coarse controller for calculating an oscillation frequency by using the count value input from the counter and selecting the coarse tuning data so that the calculated oscillation frequency approaches a reference frequency of a previously selected channel; And And an amplitude controller for determining an amplitude tuning data that causes the swing amplitude of the voltage-controlled oscillator to approach a reference amplitude according to a result of comparing the output swing amplitude of the voltage-controlled oscillator with a reference amplitude. The method according to claim 1, The voltage controlled oscillator includes a coarse tuning unit in which a plurality of tuning cells are connected in parallel between a first output terminal and a second output terminal through which a differential signal is output, respectively, and the coarse tuning unit includes a coarse tuning unit And the capacitance is varied according to the frequency of the input signal. The method of claim 2, Wherein each tuning cell has a plurality of capacitors connected to each other through a switch between a first output terminal and a second output terminal and the switch is opened or closed in accordance with coarse tuning data of the coarse control unit to adjust a capacitance of the tuning cell Oscillating frequency tuning device. The method of claim 3, Wherein the capacitors of the respective tuning cells are set to have different capacitances. The method according to claim 1, The voltage-controlled oscillator includes a plurality of tuning cells connected in parallel between a first output terminal and a second output terminal through which differential signals are output, and each tuning cell has an amplitude tuning section ; And an amplitude detector for detecting a swing amplitude of the differential signal input from the first output terminal and the second output terminal and for comparing the detected swing amplitude and the reference amplitude with each other. The method of claim 5, Wherein the amplitude detector outputs data as a result of comparing the swing amplitude and the reference amplitude to the amplitude controller. The method according to claim 1, Wherein the amplitude controller controls the voltage controlled oscillator with tuning data having a preset initial value while the coarse controller is operating. The method of claim 7, Wherein the tuning data of the initial value is a value that maximizes a swing amplitude of the voltage-controlled oscillator. The method according to claim 1, Controlling the first and second control voltages to be sequentially applied to the voltage controlled oscillator, calculating a slope of the Kvco curve using the first and second oscillation frequencies obtained from the counter, Further comprising a Kvco control unit for selecting Kvco tuning data to be close to the slope. The method of claim 9, Wherein the Kvco curve is a gain curve of the oscillation frequency selected by the coarse tuning data of the coarse control unit. The method of claim 9, Wherein the voltage controlled oscillator includes a Kvco tuning unit in which a plurality of tuning cells are connected in parallel between a first output terminal and a second output terminal to which the differential signals are respectively output and wherein each tuning cell has a capacitance Wherein the tuning frequency is variable. The method of claim 11, Each tuning cell of the Kvco tuning section includes a plurality of varactors connected between first and second output terminals and a multiplexer for selectively inputting a high voltage or a control voltage to a common node of the plurality of varactors in accordance with Kvco tuning data Frequency tuning device. The method of claim 9, The first control voltage is approximately

Voltage, and the second control voltage is approximately

Frequency oscillation frequency tuning device. The method of claim 9, Wherein the Kvco control unit controls the voltage-controlled oscillator with tuning data of a preset initial value while the coarse control unit is operating. A voltage-controlled oscillator for variably controlling an oscillation frequency according to an input control voltage and at least one tuning data; A counter for counting a signal output from the voltage-controlled oscillator for a predetermined time; A coarse controller for calculating an oscillation frequency by using the count value input from the counter and selecting the coarse tuning data so that the calculated oscillation frequency approaches a reference frequency of a previously selected channel; And Controlling the first and second control voltages to be sequentially applied to the voltage controlled oscillator, calculating a slope of the Kvco curve using the first and second oscillation frequencies obtained from the counter, And a Kvco control unit for selecting Kvco tuning data to be close to the slope. 16. The method of claim 15, The voltage controlled oscillator includes a coarse tuning unit in which a plurality of tuning cells are connected in parallel between a first output terminal and a second output terminal through which a differential signal is output, respectively, and the coarse tuning unit includes a coarse tuning unit And the capacitance is varied according to the frequency of the input signal. 18. The method of claim 16, Wherein each of the tuning cells has a plurality of capacitors connected to each other through a switch between a first output terminal and a second output terminal and the switch is opened or closed in accordance with the coarse tuning data of the coarse control unit to adjust a capacitance of the tuning cell Broadband oscillation frequency tuning device. 16. The method of claim 15, Wherein the Kvco curve is a gain curve of the oscillation frequency selected by the coarse tuning data of the coarse control unit. 16. The method of claim 15, Wherein the voltage controlled oscillator includes a Kvco tuning unit in which a plurality of tuning cells are connected in parallel between a first output terminal and a second output terminal to which the differential signals are respectively output and wherein each tuning cell has a capacitance Wherein the tuning frequency is variable. The method of claim 19, Each tuning cell of the Kvco tuning section includes a plurality of varactors connected between first and second output terminals and a multiplexer for selectively inputting a high voltage or a control voltage to a common node of the plurality of varactors in accordance with Kvco tuning data Frequency tuning device. 16. The method of claim 15, The first control voltage is approximately

Voltage, and the second control voltage is approximately

Frequency oscillation frequency tuning device. A first step of controlling at least one or more tuning data for varying an oscillation frequency of the voltage-controlled oscillator to a predetermined initial value when a channel selection command is input; A second step of calculating an oscillation frequency output from the voltage controlled oscillator according to the initialized tuning data and comparing the oscillation frequency with a reference frequency of a previously selected channel; And And a third step of determining coarse tuning data having a Kvco curve whose oscillation frequency is close to a reference frequency according to the comparison result and controlling a capacitance of the voltage controlled oscillator with the determined tuning data, Way. 23. The method of claim 22, Wherein the tuning data includes: coarse tuning data for adjusting a capacitance of a voltage-controlled oscillator such that an oscillation frequency of the voltage-controlled oscillator has a Kvco curve approximating a reference frequency of a selected channel; And Kvco tuning data for adjusting the capacitance of the voltage-controlled oscillator such that the swing amplitude of the oscillation frequency is close to the set reference amplitude, and amplitude tuning data for adjusting the resistance of the voltage-controlled oscillator A tuning method for broadband oscillation frequency characterized by. 23. The method of claim 22, Wherein the second step comprises:

Applying a voltage; Counting a frequency output from the voltage-controlled oscillator according to the applied voltage and calculating an oscillation frequency; And comparing the calculated oscillation frequency with a reference frequency for the selected channel. 23. The method of claim 22, After performing the third step, A fourth step of sequentially applying first and second control voltages to the voltage-controlled oscillator and, as a result, calculating first and second oscillation frequencies sequentially output from the voltage-controlled oscillator; And a fifth step of calculating the slope of the Kvco curve using the calculated first and second oscillation frequencies and then controlling the capacitance of the voltage-controlled oscillator by selecting Kvco tuning data such that the calculated slope approaches a preset slope Wherein the tuning step further performs the step of tuning the broadband oscillation frequency. 26. The method of claim 25, The first control voltage is approximately

Voltage, and the second control voltage is approximately

Wherein the frequency of the tuning frequency of the wideband oscillation frequency is set to a predetermined value. 23. The method of claim 22, After performing the third step, A fourth step of applying a preset control voltage to the voltage controlled oscillator; And an amplitude tuning data determining a swing amplitude of the voltage-controlled oscillator to be close to a reference amplitude according to a result of comparing the swing amplitude and the reference amplitude of the differential signal output from the voltage-controlled oscillator, And a fifth step of controlling the resistance of the oscillator. 26. The method of claim 25, After performing the fifth step, A sixth step of applying a preset control voltage to the voltage controlled oscillator; And an amplitude tuning data determining a swing amplitude of the voltage-controlled oscillator to be close to a reference amplitude according to a result of comparing the swing amplitude and the reference amplitude of the differential signal output from the voltage-controlled oscillator, And a seventh step of controlling the resistance of the oscillator. 26. The method of claim 25, After performing the fifth step, A sixth step of applying a preset control voltage to the voltage controlled oscillator; A seventh step of calculating an oscillation frequency output from the voltage controlled oscillator and comparing the oscillation frequency with a reference frequency of a previously selected channel; And a step of determining coarse tuning data having a Kvco curve whose oscillation frequency is close to a reference frequency according to the comparison result and controlling a capacitance of the voltage controlled oscillator with the determined tuning data, Frequency tuning method.

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