KR100541097B1 - VOLTAGE CONTROLLED OSCILLATOR WITH CONTROLLING OUTPUT POWER LEVEL[dB] - Google Patents

Abstract

The present invention relates to a voltage controlled oscillator (VCO) having a level adjustment function, which is composed of two buffer parts and is capable of level adjustment of an output signal in one buffer part. The present invention includes a resonator for selecting a signal having a predetermined frequency by using a first input voltage V _T ; A first buffer unit which oscillates and amplifies the signal having a predetermined frequency and outputs the first level signal having a predetermined level; A second buffer unit converting the first level signal into a second level signal having a level that varies according to a predetermined control current and outputting the second level signal; And a current controller configured to control the magnitude of the control current according to the magnitude of the second input voltage Vin, and output a first level signal having a constant level and a second level signal that varies according to the magnitude of the control current. It is characterized by outputting as a signal. According to the configuration of the present invention described above, the present invention can be applied to a mobile communication terminal such as a cellular phone and a common use of the resonator, so that the voltage controlled oscillator can be reduced in size and weight. In addition, by adding an LC resonant circuit to the output terminal of the second buffer unit, it is possible to prevent the harmonic components of the second harmonic and the third harmonic from increasing.

VCO, Buffer, Resonator, LC Resonance Circuit, Radio, Current Control

Description

VOLTAGE CONTROLLED OSCILLATOR WITH CONTROLLING OUTPUT POWER LEVEL [dB]}             

1 is a block diagram of a transmitter in a general wireless communication system.

2 is a configuration diagram of a general voltage controlled oscillator.

3 is a configuration diagram of a voltage controlled oscillator having a level adjusting function according to the present invention.

* Description of the symbols for the main parts of the drawings *

100: resonance portion 200: first buffer portion

210: oscillator 220: amplifier

300: second buffer unit 400: current control unit

L: Inductor (Strip Line) R: Resistor

C: Capacitor VD: Varactor Diode

TR: Transistor V _T : Resonator first input voltage

Vin: second input voltage of the current controller Vcc: power supply voltage

The present invention relates to a voltage controlled oscillator (VCO: voltage controlled) having a level adjustment function, and more specifically, a voltage control generator applicable to a mobile communication terminal such as a cellular phone with two buffer units, and configured as one buffer unit. The unit relates to a voltage controlled oscillator having a level adjustment function for outputting a signal having a constant level and the other buffer unit for outputting a signal whose level is changed by adjusting a current.

In general, cellular phone devices have been developed as mobile communication devices that users move and talk, and cell phone subscribers are continuously increasing. As the number of mobile phone users increases, mobile phone users want to perform more functions on their mobile phones. Many developments have been made to accommodate this, and many functions have been implemented in mobile phones.

One of the requirements of these users is that cell phone users may want to communicate between cell phones without passing through a base station. Especially in mountainous areas such as incommunicable areas, areas where there is no base station to be able to make calls, places where call sensitivity is low, or calls that are congested and where it is difficult to communicate through base stations, users can synchronize their frequencies in advance. I wanted to.

In other words, the number of users who want to use a mobile phone as a radio has increased.

1 is a block diagram of a transmitter in a general wireless communication system, in which an intermediate frequency signal S _in provided from a baseband processor of the radio communication system is input to a mixer 11 on the transmitter side. Then, the mixer 11 transmits a signal S _out having a desired frequency according to a frequency difference between the frequency F _vco provided from a voltage controlled oscillator (VCO) 12 and the transmission signal S _in . ). The transmitted signal is amplified to a desired size by a power amplifier (PA) 14 and then radiated through the antenna 15.

Here, a phase locked loop (PLL) compares a phase difference between a predetermined reference signal and an oscillation output F _vco fed back from the voltage controlled oscillator 12 to the voltage controlled oscillator 12. Adjust the applied input voltage (V _T ).

As described above, the voltage controlled oscillator 12 currently used in a wireless communication system can provide a desired frequency output.

FIG. 2 is a configuration diagram of a general voltage controlled oscillator. As shown in FIG. 2, the voltage controlled oscillator 12 uses a predetermined frequency signal using an input voltage V _T provided from the phase locked loop 13. And a resonator unit 10 for selecting and a buffer unit 20 for oscillating and amplifying a predetermined frequency signal selected by the resonator unit 10.

That is, the single band voltage controlled oscillator 11 is composed of one resonator 10 and a buffer 20.

However, when implementing a dual band voltage controlled oscillator, the dual band voltage controlled oscillator should be composed of two resonators and a buffer. In this case, the number of resonators and buffers configured according to the frequency passband of the voltage controlled oscillator increases, thereby increasing the space occupied by the components in the voltage controlled oscillator and increasing the material requirements, thereby increasing the development cost.

In addition, as described above, when implementing a voltage-controlled oscillator applied to a cellular phone according to the user's request, the conventional voltage-controlled oscillator outputs a signal having the same level of power, thus transmitting the signal without passing through the base station It is not available for radios. Therefore, in order to apply the conventional voltage controlled oscillator to a mobile phone with a radio, a separate additional circuit must be required.

In addition, since the voltage controlled oscillator to be applied to each of the radio and the mobile phone must be implemented, there is a problem in that the space occupied by components in the voltage controlled oscillator increases and the development cost according to material requirements increases, such as the dual band voltage controlled oscillator.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object thereof is to implement a voltage controlled oscillator (VCO: voltage controlled) that can be applied to a mobile communication terminal such as a cellular phone. It consists of a buffer section, one buffer section outputs a signal with a constant level, and the other buffer section provides a voltage controlled oscillator with a level adjustment function that outputs a signal whose level is variable by adjusting the current.

As a means for achieving the above object, the voltage controlled oscillator having the level adjusting function of the present invention
A resonator configured to select a signal having a predetermined frequency by using the first input voltage V _T ;
A first buffer unit which oscillates and amplifies the signal having a predetermined frequency and outputs the first level signal having a predetermined level;
A second buffer unit converting the first level signal into a second level signal having a level that varies according to a predetermined control current and outputting the second level signal; And
Current control unit for controlling the magnitude of the control current according to the magnitude of the second input voltage (Vin)

Including, a first level signal having a constant level and a second level signal that is variable according to the magnitude of the control current, characterized in that for outputting the output signal.

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Hereinafter, a voltage controlled oscillator having a level adjusting function according to the present invention will be described with reference to the accompanying drawings.

FIG. 3 is a configuration diagram of a voltage controlled oscillator having a level adjusting function according to the present invention. Referring to FIG. 3, the present invention provides a resonator unit for selecting a predetermined frequency signal using a first input voltage V _T. 100, the first buffer unit 200 for oscillating and amplifying a predetermined frequency signal selected by the resonator unit 100 and outputting the signal as a constant first level signal, and the first buffer according to the intensity of the applied current. The second buffer unit 300 converts the output signal of the unit 200 to a predetermined second level and outputs the current, and the current applied to the second buffer unit 200 according to the strength of the second input voltage Vin. It includes a current control unit 400 for adjusting the intensity of the.

The first input voltage V _T input to the resonator 100 is provided from a phase locked loop (PLL) (see FIG. 1).

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The resonator 100 and the first buffer unit 200 shown in FIG. 3 are a general configuration of a voltage controlled oscillator. The resonator unit 100 and the first buffer unit 200 described below are configured in accordance with the present invention. Will be in accordance with the implementation.

The resonator 100 includes a first inductor L1 connected to an input terminal of the resonator 100 to which the first input voltage V _T is applied from the phase locked loop PLL (see FIG. 1). A first capacitor C1 connected to the input terminal of the resonator 100 and the other end of the ground, a varactor diode VD connected to a cathode of the first inductor L1 and a ground of the cathode; A third capacitor C2 having one end connected to the contact point of the first inductor L1 and the varactor diode VD, and a third end having one end connected to the other end of the second capacitor C2 and the other end being grounded A capacitor C2, a strip line L2 having one end connected to a contact point of the second capacitor C2 and the third capacitor C3 and the other end being grounded, and one end of the strip line L2 and the first And a fourth capacitor C4 connected to the contacts of the second and third capacitors C2 and C3.

The first inductor L1 and the first capacitor C1 are connected to the input terminal of the resonator 100 to prevent the signal selected by the resonator 100 from leaking to the input terminal, thereby preventing external noise from entering. Block it.

The varactor diode VD acts as a variable capacitance according to the magnitude of the first input voltage V _T to change the frequency according to the input signal.

In addition, the second capacitor C2, the strip line L2, and the varactor diode VD form an LC resonant circuit and serve as a filter for passing only signals of a desired frequency band.

The fourth capacitor C4 passes the signal filtered by the LC resonant circuit to the first buffer unit 200, and the power supply voltage Vcc of the first buffer unit 200 flows into the LC resonant circuit. Block it from becoming

The first buffer unit 200 oscillates a signal resonated by the first resonator unit 100 using a first transistor TR1. The oscillation unit 210 of the first buffer unit 200 has one end. A third resistor R3 connected to the fourth capacitor C4 and the other end of which is grounded, and one end thereof is connected to a contact point of the third resistor R3 and the fourth capacitor C4, and the other end thereof is a fourth resistor R4; ) Is connected to the fifth capacitor C5, one end of which is connected to the contact point of the fifth capacitor C5 and the fourth resistor R4, and the other end of the sixth capacitor C6 is grounded, and the base is the fourth capacitor C5. The first transistor TR1 is connected to the contact point of the capacitor C4 and the third resistor R3 and the emitter is connected to the contact point of the fourth resistor R4 and the fifth capacitor C5.

The first transistor TR1 amplifies the signal passing through the fourth capacitor C4, and the fifth capacitor C5 connects the emitter and the base of the first transistor TR1 to the first transistor. By applying the signal emitted to the emitter of TR1 back to the base and feeding back, the frequency filtered by the resonator 100 is oscillated.

In addition, the fourth resistor R4 and the third resistor R3 connected to the emitter of the first transistor TR1 stabilize the bias voltage at which the first transistor TR1 changes rapidly with temperature. The sixth capacitor C6 connected to the emitter of the first transistor TR1 discharges an unwanted signal of the amplified signal from the first transistor TR1 to ground.

The first buffer unit 200 oscillates a signal resonated by the first resonator unit 100 using a first transistor TR1 and has a second gain higher than that of the first transistor TR1. The transistor TR2 is used to amplify the signal oscillated by the first transistor TR1.

The amplification unit 220 of the first buffer unit 200 has one end connected to the emitter of the first transistor TR1 and the other end connected to the base of the second transistor TR2 so that the first transistor TR1 is connected. The seventh capacitor (C7) for inputting the output signal of the second transistor (TR2), and one end is connected to the collector of the second transistor (TR2) and the other end is grounded to the second transistor (TR2) A ninth capacitor C9 for preventing a phase from being applied, a third inductor L3 having one end connected to a power supply voltage Vcc and the other end connected to a second transistor TR2, and one end of the third inductor An eighth capacitor C8 connected to the contact of L3 and the power supply voltage Vcc and the other end of which is grounded, one end of which is connected to a contact of the second transistor TR2 and the third inductor L3, and the other end of which is grounded. The eleventh capacitor C11 and one end thereof are connected to a contact point of the eleventh capacitor C11 and the second transistor TR2 The other end includes a tenth capacitor C10 connected to the output end of the first buffer unit 200.

Here, the third inductor L3 and the eighth capacitor C8 prevent the signal amplified by the first buffer unit 200 from leaking to the outside through the power supply voltage Vcc.

The tenth capacitor C10 blocks the power voltage Vcc from flowing out to the output terminal of the first buffer unit 200, and blocks noise from flowing into the first buffer unit 200 from the output terminal. .

The eleventh capacitor C11 sets a frequency pass band of the signal output from the second transistor TR1 to improve the harmonics of the second harmonic and the third harmonic.

The second buffer unit 300 includes a third transistor TR3, from which the signal output from the second transistor TR2 is input to the base, one end of which is connected to the power supply voltage Vcc, and the other end of the third transistor TR3. The fourth inductor (L4) connected to the), one end is connected to the contact point of the fourth inductor (L4) and the power supply voltage (Vcc), the other end is grounded the thirteenth capacitor (C13), one end is the third transistor A fifteenth capacitor C15 connected to the contact point of TR3 and the fourth inductor L4 and the other end of which is grounded, and a first end thereof connected to the contact point of the fifteenth capacitor C15 and the third transistor TR3. A sixteen capacitor (C16), one end is connected to the sixteenth capacitor (C16) and the other end is connected to the output terminal of the second buffer unit 300, the fifth inductor (L5), one end is the fifth inductor (L5) And a sixteenth capacitor C16 connected to the contact of the output terminal of the second buffer unit 300 and the other end connected to the current control unit 400.

Here, the fourth inductor (L4) and the thirteenth capacitor (C13), like the third inductor (L3) and the eighth capacitor (C8), the signal amplified by the second buffer unit 300 is a power supply voltage It prevents leakage to the outside through the (Vcc) end, and blocks the external noise flowing into the second buffer unit 300.

Like the tenth capacitor C10, the fifteenth capacitor C15 blocks the power supply voltage Vcc from flowing out to the output terminal of the second buffer unit 300, and noise is output from the second output terminal. It blocks the flow into the buffer unit 300.

Like the eleventh capacitor C11, the fourteenth capacitor C14 sets a frequency pass band of the signal output from the third transistor TR3, and primarily performs harmonics of the second harmonic and the third harmonic. To improve.

In addition, the fifth inductor L5 and the sixteenth capacitor C16, which are features of the present invention, form an LC resonant circuit, thereby resetting the frequency passband set by the fourteenth capacitor C14 more sharply. The signal emitted from the second buffer unit 300 is secondarily filtered, and harmonics such as second harmonics and third harmonics may also be secondaryly improved.

The current controller 400 includes a seventh resistor R7 having one end connected to an emitter of the third transistor TR3 and an eighth resistor having one end connected to the seventh resistor R7 and the other end grounded. R8) and a switch transistor SWTR having a base connected to a second input voltage Vin and a collector connected to a contact point of the seventh resistor R7 and an eighth resistor R8 and the emitter grounded. .

When the voltage input to the base is high, the switch transistor SWTR is switched on to operate only the seventh resistor R7. Therefore, since the emitter current of the third transistor TR3 increases, the output power of the second buffer unit 300 increases, and the output power increases, so that the signal level of the second buffer unit 300 increases. do.

In addition, when the voltage input to the base is low, the switch transistor SWTR is turned off to operate the seventh resistor R7 and the eighth resistor R8. Accordingly, the emitter current of the third transistor TR3 decreases, so that the output power of the second buffer unit 300 decreases and the output power decreases, so that the signal level of the second buffer unit 300 decreases. Done.

As described above, the signal level of the second buffer unit 300 may be adjusted according to the on / off of the switch transistor SWTR of the current control unit 400. In this case, the signal level of the seventh resistor R7 may be adjusted. The higher the resistance value of the eighth resistor R8 is, the smaller the intensity of the current applied to the second buffer unit 300 is.

In the above-described configuration, according to the present invention, the sixteenth capacitor C16 is used to selectively use the sixteenth capacitor C16 according to whether the signal input to the current controller 400 is high or low. One end of (C16) is connected to the base of the current control unit 400 and the other end is connected to the output terminal of the second buffer unit 300.

That is, when the high signal is input to the current controller 400, the sixteenth capacitor C16 acts as an inductor, and when the low signal is input to the current controller 400, the sixteenth capacitor ( C16) acts as a capacitor to act as an LC resonant circuit for filtering the output signal of the second buffer unit 300.

According to the present invention, the voltage controlled oscillator is composed of two buffer parts, so that the first buffer part outputs a signal having a constant level, and the second buffer part outputs a signal whose level can be adjusted. By using the resonator in common, the voltage-controlled oscillator can be reduced in size and weight.

In addition, by adding an LC resonant circuit to the output terminal of the second buffer unit, it is possible to prevent the harmonic components of the second harmonic and the third harmonic from increasing.

Claims (3)

A resonator configured to select a signal having a predetermined frequency by using the first input voltage V _T ; A first buffer unit which oscillates and amplifies the signal having a predetermined frequency and outputs the first level signal having a predetermined level; A second buffer unit converting the first level signal into a second level signal having a level that varies according to a predetermined control current and outputting the second level signal; And Current control unit for controlling the magnitude of the control current according to the magnitude of the second input voltage (Vin) A voltage controlled oscillator having a level adjusting function, comprising: outputting a first level signal having a constant level and a second level signal varying according to the magnitude of the control current as an output signal. The method of claim 1, wherein the second buffer portion A third transistor TR3 to which the first level signal is input as a base; A fourth inductor L4 having one end connected to a power supply voltage Vcc and the other end connected to the third transistor TR3; A thirteenth capacitor C13 having one end connected to a contact point of the fourth inductor L4 and the power supply voltage Vcc and the other end being grounded; A fifteenth capacitor C15 having one end connected to a contact point of the third transistor TR3 and the fourth inductor L4 and the other end being grounded; A sixteenth capacitor C16 having one end connected to a contact point of the fifteenth capacitor C15 and the third transistor TR3; A fifth inductor L5 having one end connected to the sixteenth capacitor C16 and the other end connected to an output terminal of the second level signal; And A sixteenth capacitor C16 having one end connected to a contact point of the output terminal of the fifth inductor L5 and the second level signal and the other end connected to the current controller; Voltage control device having a level adjustment function comprising a. According to claim 2, wherein the current control unit A seventh resistor R7 having one end connected to the emitter of the third transistor TR3; An eighth resistor R8 having one end connected to the seventh resistor R7 and the other end grounded; And A switch connected to a base of the second input voltage Vin, a collector connected to a contact point of the seventh resistor R7 and the eighth resistor R8, and an emitter grounded; Voltage control device having a level adjustment function comprising a.

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