JP2008271220A - Integrated circuit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for coping with a variation in an f-V characteristic of a VCO (voltage controlled oscillator) about a frequency synthesizer provided with the VCO. <P>SOLUTION: This integrated circuit device is provided with a first frequency synthesizer provided with a first voltage controlled oscillator whose oscillation frequency f<SB>1</SB>changes in accordance with control voltage V<SB>1</SB>to oscillate a signal of a frequency corresponding to a reference frequency; a second frequency synthesizer provided with a second voltage controlled oscillator whose oscillation frequency f<SB>2</SB>changes in accordance with control voltage V<SB>2</SB>and provided on the same chip as that of the first frequency synthesizer to oscillate a signal of a frequency corresponding to the reference frequency; and a comparator for monitoring the control voltage V<SB>1</SB>of the first voltage controlled oscillator, comparing the monitored control voltage V<SB>1</SB>with reference voltage when the frequency of the first frequency synthesizer is locked and changing the f<SB>2</SB>-V<SB>2</SB>(oscillation frequency-control voltage) characteristic of the second voltage controlled oscillator on a basis of a comparison result between the control voltage V<SB>1</SB>and the reference voltage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an integrated circuit device.

The oscillation frequency f of the VCO (voltage controlled oscillator) is determined by the resonance frequency of the LC resonance circuit as shown in equation (1). L represents the inductance of the resonant circuit, and C represents the capacitance of the resonant circuit.

  For example, a variable-capacitance diode whose capacitance value changes in accordance with an applied voltage is employed in the VCO resonance circuit. Thereby, the circuit characteristic of the VCO that the oscillation frequency changes according to the control voltage is realized.

  The VCO is employed in, for example, a frequency synthesizer (Patent Documents 1 and 2). The frequency synthesizer is usually composed of a phase comparator, a loop filter, a VCO, and a frequency divider. Frequency synthesizers are widely used in devices that handle radio waves, such as televisions, radios, mobile phones, and cordless phones.

  However, the variable capacitance diode has a drawback that the capacitance value varies greatly for each variable capacitance diode due to manufacturing variations. Therefore, the fV (oscillation frequency-control voltage) characteristics of a VCO having a variable capacitance diode vary greatly from one VCO to another.

For example, consider a VCO designed to achieve an oscillation frequency of 0.9 to 1.1 GHz with a control voltage of 0.76 to 1.66V. In this case, if the variation of the capacitance value of the variable capacitance diode is large, an oscillation frequency of 0.9 GHz cannot be obtained even if the control voltage is further lowered from 0.76V, or the control voltage is further raised from 1.66V. However, a situation may occur in which an oscillation frequency of 1.1 GHz cannot be obtained. Such a situation is naturally undesirable for a frequency synthesizer equipped with a VCO.
JP 2002-261607 A Japanese National Patent Publication No. 11-514511

  The present invention relates to a frequency synthesizer including a VCO, and an object thereof is to propose a method for dealing with variations in fV characteristics of the VCO.

The embodiment of the present invention includes, for example, a first frequency synthesizer that includes a first voltage controlled oscillator whose oscillation frequency f ₁ changes according to the control voltage V _1, and that oscillates a signal having a frequency according to the reference frequency, A second voltage-controlled oscillator whose oscillation frequency f ₂ changes according to the voltage V ₂ is provided on the same chip as the first frequency synthesizer, and oscillates a signal having a frequency corresponding to the reference frequency. The control voltage V ₁ of the second frequency synthesizer and the first voltage controlled oscillator is monitored, and the control voltage V ₁ and the reference voltage monitored when the frequency of the first frequency synthesizer is locked comparing, based on a comparison result between the reference voltage and the control voltage V _1, f ₂ -V ₂ of the second voltage controlled oscillator - a comparator for varying the (oscillation frequency control voltage) characteristics An integrated circuit device, characterized in that it comprises.

The embodiment of the present invention includes, for example, a first frequency synthesizer that includes a first voltage controlled oscillator whose oscillation frequency f ₁ changes according to the control voltage V _1, and that oscillates a signal having a frequency according to the reference frequency, A second voltage-controlled oscillator whose oscillation frequency f ₂ changes according to the voltage V ₂ is provided on the same chip as the first frequency synthesizer, and oscillates a signal having a frequency corresponding to the reference frequency. The control voltage V ₁ of the second frequency synthesizer and the first voltage controlled oscillator is monitored, and the control voltage V ₁ and the reference voltage monitored when the frequency of the first frequency synthesizer is locked comparing, based on a comparison result between the reference voltage and the control voltage V _1, f ₁ -V ₁ of the first voltage controlled oscillator (oscillation frequency - control voltage) characteristics and said second voltage controlled oscillator f ₂ -V ₂ - is an integrated circuit device characterized by comprising a comparator for changing the (oscillation frequency control voltage) characteristics.

  The present invention relates to a frequency synthesizer provided with a VCO, and proposes a method for dealing with variations in fV characteristics of the VCO.

(First embodiment)
FIG. 1 is a circuit block diagram of an integrated circuit device 101 according to the first embodiment. The integrated circuit device 101 includes a reference signal source 111, a first frequency synthesizer 112A, a second frequency synthesizer 112B, and a comparator 113. In the integrated circuit device 101, as shown in FIG. 1, the first frequency synthesizer 112A and the second frequency synthesizer 112B are provided on the same IC chip 121, that is, formed in the same monolithic semiconductor. Yes.

  The reference signal source 111 is a circuit that generates a reference signal having a reference frequency. The reference signal source 111 is constituted by, for example, a crystal oscillator that oscillates a signal.

  The first and second frequency synthesizers 112A and B are circuits that oscillate a signal having a frequency corresponding to a reference frequency. The first and second frequency synthesizers 112A and 112B respectively include first and second phase comparators 131A and 131B, first and second loop filters 132A and 132B, and first and second VCOs (voltages). Controlled oscillator) 133A, B and first and second frequency dividers 134A, B. Here, the first frequency synthesizer 112A is a frequency synthesizer for reception, and the second frequency synthesizer 112B is a frequency synthesizer for transmission.

The first and second phase comparators 131A and B are circuits for comparing the phase of the output signal of the first and second frequency dividers 134A and 134B with the phase of the reference signal, respectively. The first and second loop filters 132A and B are filters that smooth the output signals of the first and second phase comparators 131A and 131B, respectively. The first and second VCOs 133A and B are circuits that oscillate signals according to the output signals (control voltages V ₁ and V ₂ ) of the first and second loop filters 132A and B, respectively. The oscillation frequencies f ₁ and f ₂ of the first and second VCOs 133A and 133B change according to the control voltages V ₁ and V ₂ , respectively. The output signals of the first and second VCOs 133A and B are input to the first and second frequency dividers 134A and 134B, respectively, and also output to the outside of the first and second frequency synthesizers 112A and B. . The first and second frequency dividers 134A and 134B are circuits that divide the output signals of the first and second VCOs 133A and 133B, respectively.

Comparator 113 compares the control voltage V ₁ and the reference voltage V _ref of the first VCO133A, a circuit for outputting a comparison result between the control voltage V ₁ and the reference voltage V _ref of the first VCO133A. The integrated circuit device 101 in FIG. 1 includes two comparators 113 here, but may include one comparator 113 or may include three or more comparators 113. Comparator 113X, Y, respectively, to monitor the control voltage V ₁ of the first VCO133A, comparing the monitored control voltage V ₁ and the reference voltage V _ref when the frequency of the first frequency synthesizer 112A is locked Then, signals S _X and S _Y corresponding to the comparison result between the control voltage V ₁ and the reference voltage V _ref are output. The signals S _X and S _Y are input to the second VCO 133B and affect the f ₂ -V ₂ (oscillation frequency-control voltage) characteristics of the _second VCO 133B. Thus, the comparator 113 compares the control voltage V ₁ and the reference voltage V _ref, based on the comparison result between the control voltage V ₁ and the reference voltage V _ref, f ₂ -V ₂ characteristics of the second VCO133B It is the composition which changes.

The second VCO 133B includes switches SW _X and SW _Y. The on / off switching of the switches SW _X and SW _Y affects the f ₂ -V ₂ characteristics of the _second VCO 133B. Switch SW _X, each switching of SW _Y ON-OFF, the signal S _X, is controlled by the S _Y. The comparator 113 changes the f ₂ -V ₂ characteristic of the _second VCO 133B by switching the switches SW _X and SW _Y on and off with the signals S _X and S _Y. Switch SW _X, details and the switch SW _X of SW _Y, the exact circuit configuration near SW _Y will be described later.

  Hereinafter, the first and second VCOs 133A and B will be described.

Variable capacitance diodes are employed for the resonance circuit of the first VCO 133A and the resonance circuit of the second VCO 133B, respectively. Therefore, the f ₁ -V ₁ (oscillation frequency-control voltage) characteristic of the first VCO 133A and the f ₂ -V ₂ (oscillation frequency-control voltage) characteristic of the second VCO 133B may vary from one VCO to another. .

Variations in the f ₁ -V ₁ characteristic of the first VCO 133A and the f ₂ -V ₂ characteristic of the second VCO 133B will be described with reference to FIG. FIG. 2 is a graph showing fV characteristics of a certain VCO having a variable capacitance diode. This VCO is a VCO for obtaining an oscillation frequency of 0.9 to 1.1 GHz, that is, a VCO having an oscillation frequency variable range of 0.9 to 1.1 GHz. It is designed to realize an oscillation frequency of ˜1.1 GHz with a control voltage of 0.76 to 1.66V. On the other hand, dotted lines L ₁ and L ₂ represent examples of fV characteristics when the capacitance values of the variable capacitance diodes vary. In the case of the dotted line L ₁ , an oscillation frequency of 0.9 GHz cannot be obtained even when the control voltage is lowered to 0.5 V, and in the case of the dotted line L ₂ , even if the control voltage is raised to 2.5 V, 1.1 GHz is obtained. The oscillation frequency cannot be obtained.

Therefore, in this embodiment, the fV characteristic of FIG. 2 is changed as the fV characteristic of FIG. That is, the fV characteristic such as the dotted line L ₁ moves downward in the f axis (V axis rightward), and the fV characteristic such as the dotted line L ₂ moves in the f axis upward (V axis leftward). Let The dotted lines L ₁ and L ₂ are moved so as to cross the solid line L at 1.0 GHz, respectively. In this way, in this embodiment, it is possible to correct the variation in the fV characteristics of the VCO. Such variation correction is applied only to the second VCO 133B in the first embodiment, and is applied to both the first and second VCOs 133A and B in the second embodiment.

Note that the f ₁ -V ₁ characteristic of the _first VCO 133A and the f ₂ -V ₂ characteristic of the _second VCO 133B are qualitatively the same as the fV characteristic of the VCO. Here, it is assumed that the control voltage sensitivity of the first VCO 133A is higher than the control voltage sensitivity of the second VCO 133B.

Here, the operation of the comparator 113 will be described again from the viewpoint of variation correction. First, the comparator 113 monitors the control voltage V ₁ of the first VCO 133A, and compares the monitored control voltage V ₁ with the reference voltage V _ref when the frequency of the first frequency synthesizer 112A is locked. . This process corresponds to a process of monitoring the lock control voltage of the first VCO 133A and determining whether or not the lock control voltage is different from the set value. Thereby, the variation in the f ₁ -V ₁ characteristic of the first VCO 133A is detected. Next, the comparator 113 changes the f ₂ −V ₂ characteristic of the _second VCO 133B based on the comparison result between the control voltage V ₁ and the reference voltage V _ref . This process corresponds to a process of correcting the fluctuation of the f ₂ -V ₂ characteristic of the _second VCO 133B based on the detection result of the fluctuation of the f ₁ -V ₁ characteristic of the _first VCO 133A.

As described above, the first VCO 133A and the second VCO 133B are provided on the same chip 121. Therefore, f ₁ -V ₁ characteristic variation and f ₂ -V ₂ characteristic variation generally occur in the same direction. This is because the variation in the fV characteristics of the VCO is considered to depend on the manufacturing process. For example, when the f ₁ -V ₁ characteristic is slightly shifted upward in the f-axis, the f ₂ -V ₂ characteristic is also shifted slightly downward in the f-axis, and the f ₁ -V ₁ characteristic is shifted downward in the f-axis. when the largely deviated the, f ₂ -V ₂ characteristic deviates greatly to the f-axis downward direction. Therefore, in the first embodiment, the f ₂ -V ₂ characteristic variation is corrected based on the detection result of the f ₁ -V ₁ characteristic variation.

  In recent years, as with the integrated circuit device 101 in FIG. 1, devices including a plurality of frequency synthesizers are increasing. One reason for this is that an increasing number of devices use separate frequency synthesizers for reception processing and transmission processing. This embodiment is very effective for such a device. The present embodiment can be applied not only to a device having two frequency synthesizers but also to a device having three or more frequency synthesizers.

  In the present embodiment, it is preferable that the first frequency synthesizer 112A is a reception frequency synthesizer and the second frequency synthesizer 112B is a transmission frequency synthesizer. This is because the frequency synthesizer for transmission is generally stopped while the device is in operation, whereas the frequency synthesizer for reception is generally always operating. As a result, variation correction is always possible.

The detection result of the variation in the f ₁ -V ₁ characteristic naturally, can also be utilized to correct variations of f ₁ -V ₁ properties. In the second embodiment, based on the detection result of the variation in the f ₁ -V ₁ characteristic to correct the variation in the variation of f ₁ -V ₁ characteristics and f ₂ -V ₂ properties.

FIG. 4 is a circuit configuration example of the first VCO 133A. The VCO 133A of FIG. 4 includes two variable capacitance diodes C ₁ and C ₂ and one inductor L ₁ . In the VCO 133A of FIG. 4, an LC resonance circuit (first resonance circuit) is formed by these circuit elements. The numbers of variable capacitance diodes and inductors constituting the resonance circuit are not limited to two and one, respectively. In the resonant circuit, one or more variable capacitance diodes and one or more inductors may be arranged. The VCO 133A in FIG. 4 further includes two oscillation transistors TR ₁ and TR ₂ .

FIG. 5 is a first circuit configuration example of the second VCO 133B. 5 includes two variable capacitance diodes C ₁ and C ₂ , one inductor L ₁ , six capacitors C _adj1 , C _adj2 , C _adj3 , C _adj4 , C _adj5 , and C _adj6 , and two switches. SW _X and SW _Y are provided. In the VCO 133B of FIG. 5, an LC resonance circuit (second resonance circuit) is formed by these circuit elements. The numbers of variable capacitance diodes, inductors, capacitors, and switches constituting the resonance circuit are not limited to two, one, six, and two, respectively. The resonant circuit may include one or more variable capacitance diodes, one or more inductors, one or more capacitors, and one or more switches. The VCO 133B of FIG. 5 further includes two oscillation transistors TR ₁ and TR ₂ .

In VCO133B 5, the series connection of the C _adj1 and C _adj2, the series connection of the C _ADJ3 and C _Adj4, and a series connection of a C _ADJ5 and C _Adj6 are connected in parallel. Further, in the VCO 133B of FIG. 5, SW _X is interposed between C _adj3 and C _adj4, and SW _Y is interposed between C _adj5 and C _adj6 .

In the VCO 133B of FIG. 5, when SW _X and SW _Y are turned off, two capacitors (C _{adj1 to} C _adj2 ) are connected to the second resonance circuit. In the VCO 133B of FIG. 5, when SW _X is turned on and SW _Y is turned off, a path P _X is formed, and four capacitors (C _{adj1 to} C _adj4 ) are connected to the second resonance circuit. In the VCO 133B of FIG. 5, when SW _X and SW _Y are turned on, paths P _X and P _Y are formed, and six capacitors (C _{adj1 to} C _adj6 ) are connected to the second resonance circuit. Thus, the switches SW _X and SW _{Y serve} to _switch the conduction state of the capacitors C _adj1 to C _adj6 , that is, the connection state of the capacitors C _{adj1 to} C _adj6 to the second resonance circuit.

FIG. 6 is a second circuit configuration example of the second VCO 133B. 6 includes two variable capacitance diodes C ₁ and C ₂ , one inductor L ₁ , six capacitors C _adj1 , C _adj2 , C _adj3 , C _adj4 , C _adj5 , and C _adj6 , and two switches. SW _X and SW _Y are provided. In the VCO 133B of FIG. 6, an LC resonance circuit (second resonance circuit) is formed by these circuit elements. The numbers of variable capacitance diodes, inductors, capacitors, and switches constituting the resonance circuit are not limited to two, one, six, and two, respectively. The resonant circuit may include one or more variable capacitance diodes, one or more inductors, one or more capacitors, and one or more switches. The VCO 133B in FIG. 6 further includes two oscillation transistors TR ₁ and TR ₂ .

In the VCO 133B of FIG. 6, C _{adj1 to} C _adj6 are connected in series in the order of C _adj1 , C _adj3 , C _adj5 , C _adj6 , C _adj4 , and C _adj2 . Further, in the VCO 133B of FIG. 6, SW _X is arranged in parallel with C _{adj5 to} C _adj6 and SW _Y is arranged in parallel with C _{adj3 to} C _adj6 .

In the VCO 133B of FIG. 6, when SW _X and SW _Y are turned off, six capacitors (C _{adj1 to} C _adj6 ) are connected to the second resonance circuit. In the VCO 133B of FIG. 6, when SW _X is turned on and SW _X is turned off, a bypass P _X is formed, and four capacitors (C _{adj1 to} C _adj4 ) are connected to the second resonance circuit. In the VCO 133B of FIG. 6, when SW _Y is turned on, a bypass P _Y is formed, and two capacitors (C _{adj1 to} C _adj2 ) are connected to the second resonance circuit. Thus, the switches SW _X and SW _{Y serve} to _switch the conduction state of the capacitors C _adj1 to C _adj6 , that is, the connection state of the capacitors C _{adj1 to} C _adj6 to the second resonance circuit.

The oscillation frequency f ₁ of the VCO 133A in FIG. The oscillation frequency f ₂ of the VCO 133B shown in FIGS. 5 and 6 is expressed as in Expression (3). L represents the inductance due to the inductor L ₁ , C represents the capacitance due to the variable capacitance diodes C ₁ and C ₂ , and C _adj represents the capacitance due to the capacitors C _{adj1 to} C _adj6 . α represents variation in the capacitance value of the variable capacitance diode, and N represents the number of capacitors in a conductive state. 4 is a variable depending on V ₁ , and C and C _adj of VCO 133B in FIGS. 5 and 6 are variables depending on V ₂ and N, respectively.

Thus, the f ₂ -V ₂ characteristic of the _second VCO 133B changes according to the number of capacitors in the conductive state. Therefore, the comparator 113 can change the f ₂ −V ₂ characteristic of the _second VCO 133B by switching the switches SW _X and SW _Y on and off.

In addition to the switches SW _X and SW _Y or instead of the switches SW _X and SW _Y , the variable capacitance diode C ₁ is connected to the second resonant circuit in the second resonant circuit of FIG. 5 or FIG. A switch SW ₁ for switching the state and a switch SW ₂ for switching the connection state of the variable capacitance diode C ₂ to the second resonance circuit may be provided. In this case, the f ₂ -V ₂ characteristic of the _second VCO 133B can be changed by switching the switches SW ₁ and SW ₂ on and off.

  FIG. 7 is a flowchart relating to the operation of the integrated circuit device 101 of the first embodiment.

First, the frequency of the first synthesizer 112A is locked, and the oscillation frequency f ₁ of the first synthesizer 112A is set to a desired frequency (S101). Next, the comparator 113 monitors the control voltage V ₁ when the first synthesizer 112A is locked (S102). Next, the comparator 113 compares the control voltage V ₁ with the reference voltage V _ref for comparison (S103). Thereby, the variation in the f ₁ -V ₁ characteristic of the first VCO 133A is detected.

When the control voltage V ₁ is higher than the reference voltage V _ref , the comparator 113 changes the f ₂ -V ₂ characteristic of the second VCO 133B in the f-axis upward direction (S111). That is, the capacitance of the second resonance circuit is reduced. In the case of FIG. 5, the number of conductive capacitors is decreased. In the case of FIG. 6, the number of conductive capacitors is increased. Thereby, the variation in the f ₂ -V ₂ characteristic of the second VCO 133B is corrected.

On the other hand, when the control voltage V ₁ is lower than the reference voltage V _ref , the comparator 113 changes the f ₂ -V ₂ characteristic of the second VCO 133B downward in the f-axis direction (S112). That is, the capacitance of the second resonant circuit is increased. In the case of FIG. 5, the number of conductive capacitors is increased. In the case of FIG. 6, the number of conductive capacitors is decreased. Thereby, the variation in the f ₂ -V ₂ characteristic of the second VCO 133B is corrected.

Thereafter, the frequency of the second synthesizer 112B is locked, and the oscillation frequency f ₂ of the second synthesizer 112B is set to a desired frequency (S121).

  The integrated circuit device 101 according to the second embodiment will be described below. The second embodiment is a modification of the first embodiment, and the second embodiment will be described focusing on the differences from the first embodiment.

(Second embodiment)
FIG. 8 is a circuit block diagram of the integrated circuit device 101 of the second embodiment. The integrated circuit device 101 includes a reference signal source 111, a first frequency synthesizer 112A, a second frequency synthesizer 112B, a comparator 113, and a hold circuit 201. In the integrated circuit device 101, as shown in FIG. 8, the first frequency synthesizer 112A and the second frequency synthesizer 112B are provided on the same IC chip 121, that is, formed in the same monolithic semiconductor. Yes.

Comparator 113 compares the control voltage V ₁ and the reference voltage V _ref of the first VCO133A, a circuit for outputting a comparison result between the control voltage V ₁ and the reference voltage V _ref of the first VCO133A. The hold circuit 201 is a circuit that holds the output signal of the comparator 113. The integrated circuit device 101 of FIG. 8 includes two comparators 113 and two hold circuits 201 here, but may include one comparator 113 and one hold circuit 201. One or more comparators 113 and three or more hold circuits 201 may be provided. Comparator 113X, Y, respectively, to monitor the control voltage V ₁ of the first VCO133A, comparing the monitored control voltage V ₁ and the reference voltage V _ref when the frequency of the first frequency synthesizer 112A is locked Then, signals S _X and S _Y corresponding to the comparison result between the control voltage V ₁ and the reference voltage V _ref are output. The hold circuits 201X and Y hold the signals S _X and S _Y , respectively. The signals S _X and S _Y are respectively input to the first VCO 133A via the hold circuits 201X and Y, affect the f ₁ -V ₁ (oscillation frequency-control voltage) characteristics of the _first VCO 133A, and hold the signals. The signal is input to the second VCO 133B via the circuits 201X and Y, and affects the f ₂ -V ₂ (oscillation frequency-control voltage) characteristics of the _second VCO 133B. Thus, comparator 113, control voltages V ₁ is compared with the reference voltage V _ref, based on the comparison result between the control voltage V ₁ and the reference voltage V _ref, f ₁ -V ₁ characteristic of the first VCO133A And the f ₂ -V ₂ characteristic of the second VCO 133B.

The first VCO 133A includes switches SW _X and SW _Y. The on / off switching of these switches SW _X and SW _Y affects the f ₁ -V ₁ characteristics of the _first VCO 133A. The on / off switching of these switches SW _X and SW _Y is controlled by signals S _X and S _Y , respectively. Comparator 113, the signal S _X, the S _Y By switching these switches SW _X, SW _Y on and off, changing the f ₁ -V ₁ characteristic of the first VCO133A.

The second VCO 133B also includes switches SW _X and SW _Y. The on / off switching of these switches SW _X and SW _Y affects the f ₂ -V ₂ characteristics of the _second VCO 133B. The on / off switching of these switches SW _X and SW _Y is controlled by signals S _X and S _Y , respectively. The comparator 113 changes the f ₂ -V ₂ characteristic of the _second VCO 133B by switching the switches SW _X and SW _Y on and off by the signals S _X and S _Y.

Here, the operation of the comparator 113 will be described again from the viewpoint of variation correction. First, the comparator 113 monitors the control voltage V ₁ of the first VCO 133A, and compares the monitored control voltage V ₁ with the reference voltage V _ref when the frequency of the first frequency synthesizer 112A is locked. . This process corresponds to a process of monitoring the lock control voltage of the first VCO 133A and determining whether or not the lock control voltage is different from the set value. Thereby, the variation in the f ₁ -V ₁ characteristic of the first VCO 133A is detected. Next, the comparator 113 changes the f ₁ -V ₁ characteristic of the first VCO 133A and the f ₂ -V ₂ characteristic of the second VCO 133B based on the comparison result between the control voltage V ₁ and the reference voltage V _ref. Let This process is performed based on the detection result of the f ₁ -V ₁ characteristic variation of the first VCO 133A, and the f ₁ -V ₁ characteristic variation of the first VCO 133A and the f ₂ -V ₂ characteristic of the _second VCO 133B. This corresponds to a process for correcting variations.

Thus, in this embodiment, on the basis of the detection result of the variation in the f ₁ -V ₁ characteristic to correct the variation in the variation of f ₁ -V ₁ characteristics and f ₂ -V ₂ properties. Thus, in this embodiment, the variation correction for the first VCO 133A and the variation correction for the second VCO 133B can be executed by the common comparator 113 (and the hold circuit 201).

Thus, in this embodiment, f ₁ -V ₁ characteristic variation of the detection result of also utilized to correct variations of f ₁ -V ₁ properties. Therefore, the variation detection result may change due to variation correction of the f ₁ -V ₁ characteristic. Therefore, in this embodiment, a hold circuit 201 for holding the variation detection result is provided.

The circuit configuration example of the second VCO 133B is given as shown in FIGS. 5 and 6 as in the first embodiment. In the second embodiment, a circuit configuration example of the first VCO 133A is also given as shown in FIGS. In this case, the oscillation frequency f ₁ of the _first VCO 133A is expressed as Equation (4), and the oscillation frequency f ₂ of the _second VCO 133B is expressed as Equation (5). C of the first VCO133A, C _adj becomes dependent variables V _1, N, respectively, C the second VCO133B, C _adj is the dependent variables V _2, N respectively.

Thus, the f ₁ -V ₁ characteristic of the _first VCO 133A changes according to the number of capacitors in the conductive state. Therefore, the comparator 113 can change the f ₁ -V ₁ characteristic of the _first VCO 133A by switching on and off the switches SW _X and SW _Y constituting the first resonance circuit.

Similarly, the f ₂ -V ₂ characteristic of the _second VCO 133B changes according to the number of capacitors in the conductive state. Therefore, the comparator 113 can change the f ₂ -V ₂ characteristic of the _second VCO 133B by switching on and off the switches SW _X and SW _Y constituting the second resonance circuit.

Incidentally, the first resonant circuit as shown in FIG. 5 or FIG. 6, the switch SW _X, in addition to SW _Y, or switch SW _X, instead of SW _Y, the first resonant circuit of the variable capacitance diode C ₁ A switch SW ₁ for switching the connection state of the variable capacitance diode C ₂ and a switch SW ₂ for switching the connection state of the variable capacitance diode C ₂ to the first resonance circuit may be provided. In this case, the f ₁ -V ₁ characteristic of the _first VCO 133A can be changed by switching the switches SW ₁ and SW ₂ on and off.

Similarly, the second resonant circuit as shown in FIG. 5 or FIG. 6, the switch SW _X, in addition to SW _Y, or switch SW _X, instead of SW _Y, variable capacitance diode second resonant circuit C ₁ a switch SW ₁ for switching the connection state to be provided and the switch SW ₂ for switching the connection state to the second resonant circuit of the variable capacitance diode C _2. In this case, the f ₂ -V ₂ characteristic of the _second VCO 133B can be changed by switching the switches SW ₁ and SW ₂ on and off.

  FIG. 9 is a flowchart relating to the operation of the integrated circuit device 101 of the second embodiment.

First, the frequency of the first synthesizer 112A is locked, and the oscillation frequency f ₁ of the first synthesizer 112A is set as the center frequency (S101 ′). The center frequency is the center frequency of the variable range of the oscillation frequency. When the variable range of the oscillation frequency is 0.9 to 1.1 GHz, the center frequency is 1.0 GHz. Next, the comparator 113 monitors the control voltage V ₁ when the first synthesizer 112A is locked (S102). Next, the comparator 113 compares the control voltage V ₁ with the reference voltage V _ref for comparison (S103). Thereby, the variation in the f ₁ -V ₁ characteristic of the first VCO 133A is detected.

When the control voltage V ₁ is higher than the reference voltage V _ref , the comparator 113 sets the f ₁ -V ₁ characteristic of the first VCO 133A and the f ₂ -V ₂ characteristic of the second VCO 133B in the upward direction along the f axis. It is changed (S111 ′). That is, the capacitance of the first resonance circuit and the capacitance of the second resonance circuit are reduced. In the case of FIG. 5, the number of capacitors in the conductive state is decreased. In the case of FIG. 6, the number of conductive capacitors is increased. Thereby, the variation in the f ₁ -V ₁ characteristic of the _first VCO 133A and the variation in the f ₂ -V ₂ characteristic of the _second VCO 133B are corrected.

On the other hand, when the control voltage V ₁ is lower than the reference voltage V _ref , the comparator 113 reduces the f ₁ -V ₁ characteristic of the first VCO 133A and the f ₂ -V ₂ characteristic of the second VCO 133B below the f axis. The direction is changed (S112 ′). That is, the capacitance of the first resonance circuit and the capacitance of the second resonance circuit are increased. In the case of FIG. 5, the number of conductive capacitors is increased. In the case of FIG. 6, the number of capacitors in the conductive state is decreased. Thereby, the variation in the f ₁ -V ₁ characteristic of the _first VCO 133A and the variation in the f ₂ -V ₂ characteristic of the _second VCO 133B are corrected.

Thereafter, the frequency of the first synthesizer 112A is locked, and the oscillation frequency f ₁ of the first synthesizer 112B is set to a desired frequency (S201).

Further, the frequency of the second synthesizer 112B is locked, and the oscillation frequency f ₂ of the second synthesizer 112B is set to a desired frequency (S121).

  Note that the operation as shown in FIG. 9 is executed, for example, when a device including the integrated circuit device 101 is turned on.

1 is a circuit block diagram of an integrated circuit device according to a first embodiment. It is the graph which showed the fV characteristic of a certain VCO (before dispersion | variation correction). It is the graph which showed the fV characteristic of a certain VCO (after dispersion correction). It is a circuit configuration example of a first VCO. It is the 1st circuit structural example of 2nd VCO. It is a 2nd circuit structural example of 2nd VCO. It is a flowchart figure regarding operation | movement of the integrated circuit device of 1st Example. It is a circuit block diagram of the integrated circuit device of 2nd Example. It is a flowchart regarding operation | movement of the integrated circuit device of 2nd Example.

Explanation of symbols

101 Integrated Circuit Device 111 Reference Signal Source 112 Frequency Synthesizer 113 Comparator 121 IC Chip 131 Phase Comparator 132 Loop Filter 133 VCO
134 Divider 201 Hold circuit

Claims (5)

A first frequency synthesizer that includes a first voltage controlled oscillator whose oscillation frequency f ₁ changes according to the control voltage V ₁ , and oscillates a signal having a frequency according to the reference frequency;
A second voltage controlled oscillator whose oscillation frequency f ₂ changes according to the control voltage V ₂ is provided on the same chip as the first frequency synthesizer, and oscillates a signal having a frequency corresponding to the reference frequency. A second frequency synthesizer,
Said first monitors the control voltage V ₁ of the voltage controlled oscillator, comparing the control voltage V ₁ and the reference voltage which is monitored when the frequency of the first frequency synthesizer is locked, the control voltage An integrated circuit device comprising: a comparator that changes f ₂ -V ₂ (oscillation frequency-control voltage) characteristics of the second voltage-controlled oscillator based on a comparison result between V ₁ and the reference voltage . The first voltage controlled oscillator includes a first resonance circuit,
The first resonant circuit includes:
One or more variable capacitance diodes for the first resonant circuit;
One or more inductors for the first resonant circuit,
The second voltage controlled oscillator includes a second resonance circuit,
The second resonant circuit is:
One or more variable capacitance diodes for the second resonant circuit;
One or more inductors for the second resonant circuit;
One or more capacitors for the second resonant circuit;
One or more switches for switching the connection state of the capacitor to the second resonant circuit;
The integrated circuit device according to claim 1, wherein the comparator changes the f ₂ -V ₂ characteristic of the second VCO by switching the switch. A first frequency synthesizer that includes a first voltage controlled oscillator whose oscillation frequency f ₁ changes according to the control voltage V ₁ , and oscillates a signal having a frequency according to the reference frequency;
A second voltage controlled oscillator whose oscillation frequency f ₂ changes according to the control voltage V ₂ is provided on the same chip as the first frequency synthesizer, and oscillates a signal having a frequency corresponding to the reference frequency. A second frequency synthesizer,
Said first monitors the control voltage V ₁ of the voltage controlled oscillator, comparing the control voltage V ₁ and the reference voltage which is monitored when the frequency of the first frequency synthesizer is locked, the control voltage Based on the comparison result between V ₁ and the reference voltage, the f ₁ −V ₁ (oscillation frequency−control voltage) characteristic of the first voltage controlled oscillator and the f ₂ −V ₂ ( _second voltage controlled oscillator) An integrated circuit device comprising: a comparator that changes characteristics of (oscillation frequency-control voltage). The first voltage controlled oscillator includes a first resonance circuit,
The first resonant circuit includes:
One or more variable capacitance diodes for the first resonant circuit;
One or more inductors for the first resonant circuit;
One or more capacitors for the first resonant circuit;
One or more switches for switching the connection state of the capacitor to the first resonant circuit,
The comparator changes the f ₁ -V ₁ characteristic of the _first VCO by switching the switch,
The second voltage controlled oscillator includes a second resonance circuit,
The second resonant circuit is:
One or more variable capacitance diodes for the second resonant circuit;
One or more inductors for the second resonant circuit;
One or more capacitors for the second resonant circuit;
One or more switches for switching the connection state of the capacitor to the second resonant circuit;
The integrated circuit device according to claim 3, wherein the comparator changes the f ₂ -V ₂ characteristic of the second VCO by switching the switch.   5. The integrated circuit device according to claim 1, wherein a control voltage sensitivity of the first voltage controlled oscillator is higher than a control voltage sensitivity of the second voltage controlled oscillator. 6.

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