JP2003101343A - Frequency shift type high frequency voltage-controlled oscillation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frequency shift type high frequency voltage-controlled oscillation circuit wherein when logic of shift is inverted to the conventional circuit system, it is unnecessary to investigate a circuit again, and simple coping is enabled. SOLUTION: The oscillation circuit consists of a resonance circuit part X, a negative resistance circuit Y which outputs an oscillation signal on the basis of a resonance frequency of the resonance circuit part X, and an amplification circuit Z which contains a transistor for amplifying the oscillation signal. An anode of a variable capacitance diode is grounded via a second strip line SLS1, with which a switching diode Di is connected in parallel. A shift control terminal Vs is installed which supplies a shift control signal to one end of a switching diode Di. A DC voltage terminal Vc is installed which supplies a DC voltage to the other end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage controlled oscillator circuit suitable for a local oscillator circuit of a high frequency radio apparatus.

[0002]

2. Description of the Related Art Conventionally, it has been known that a voltage controlled oscillator is used as a transmission oscillator of a mobile communication device or other communication devices and a local oscillator of a reception unit. Although mobile communication devices in the world are divided into several systems, the number of mobile communication devices compatible with dual systems and triple systems is increasing with the progress of world horns. However, the multi-systemization increases the number of parts accordingly, and the problems of "increasing volume" and "increasing cost" cannot be avoided. Mobile communication device manufacturers are considering to solve the problem. Currently, the "direct conversion method" is becoming the mainstream as one of the solutions.
This is the conventional method called "superheterodyne" in the communication system of mobile communication devices, in which the received wave is dropped to an intermediate frequency in the receiving circuit and then converted into an audio signal. It is a method of converting into a signal. With the development of baseband ICs, that method has become possible. This makes it possible to reduce parts. In addition, this method has a great effect on a circuit compatible with multi-system. This "direct conversion method" is
With regard to the voltage controlled oscillator, one transmitting and receiving oscillator is sufficient, which is more effective. In the case of a multi-system, the voltage controlled oscillator used in the “direct conversion method” is becoming a mainstream voltage controlled oscillator in the high frequency region of the voltage controlled oscillator, for example, 3 GHz band.

However, in addition to the high frequency, this voltage controlled oscillator has a very wide frequency range and requires about 400 MHz. This is a case where dual system is taken as an example, and when the number is triple or more, the frequency range is further expanded, and the control voltage sensitivity for controlling the oscillation frequency of the voltage controlled oscillator is becoming higher. When this control voltage sensitivity becomes high, it becomes very difficult to design the PLL circuit around the voltage controlled oscillator that locks the frequency. Since the sensitivity is very high, it takes a very long time to lock the frequency, which causes a problem on the terminal, and the range of the control voltage sensitivity supported by the PLL-IC is limited. Absent. In this way, stable P while covering the frequency range
In order to configure the LL circuit and set the frequency control sensitivity low, a high frequency voltage controlled oscillator having a frequency shift function is required.

First, a general oscillator circuit, for example, a voltage controlled oscillator circuit will be described with reference to FIG. A resonance circuit unit X which includes a resonance circuit including a strip line SL, a variable capacitance diode DV, and capacitors C2 and C3 (coupling capacitors), and which supplies an external control voltage VT to the variable capacitance diode DV to control the resonance frequency. An oscillation transistor Tr that outputs an oscillation signal based on the resonance frequency of the resonance circuit section X
1. Negative resistance circuit section Y including resistors R1 and R2 and capacitors C5 to C7, and amplification circuit section Z including a transistor Tr2 for amplifying an oscillation signal, a resistor R3, capacitors C8 to C11, and an inductance element L2. It is configured.

In such an oscillator circuit, a Colpitts circuit in which the collector of the oscillating transistor Tr1 of the negative resistance circuit section Y is grounded at a high frequency is used to satisfy the oscillation condition. The resonance circuit unit X is connected to the negative circuit unit with a coupling capacitor to oscillate. Then, this oscillation signal is supplied to the amplifying transistor Tr2, is amplified here, and is oscillated and output from the output element OUT.

In this voltage controlled oscillator circuit, the resonance frequency within the variable range of the variable capacitance diode DV, and thus the oscillation frequency, can be controlled within a predetermined range.

In order to obtain two kinds of oscillation frequency bands in such a voltage controlled oscillator circuit and to widen the frequency variable range of the oscillation output, it is proposed to change the inductance component and the capacitance component of the resonance circuit stepwise. ing.

FIG. 5 shows a resonant circuit portion of the voltage controlled oscillator circuit shown in FIG. 4, which is provided with a shift circuit for switching the resonant frequency. In the shift circuit shown in FIG. 4, for example, a shift strip line SLs is arranged between the variable capacitance diode DV and the ground potential, and the switching diode Di is arranged in parallel with the strip line SLs.
Had been placed. The anode of the switching diode Di is connected to the anode side of the variable capacitance diode DV of the strip line SLs, and at the same time, the shift terminal VS to which the shift control signal is supplied via the bias resistor Rs is connected. . Further, the cathode of the switching diode Di was connected to the ground potential via the capacitor Cs.

Such a voltage controlled oscillator circuit is, for example,
The high frequency voltage controlled oscillator circuit is applied when the oscillation frequency is an oscillation output of the self-resonance frequency of the variable capacitance diode DV or the switching diode Di, for example, 3 GHz or more.

ON / OFF of this switching diode Di
Switching operation turns ON the switching diode Di.
The operation becomes inductive, and an inductance component is added to the strip line SLs. As a result, the inductance component of the resonance circuit greatly changes and the resonance frequency can be switched.

[0011]

In the conventional shift circuit system as shown in FIG. 5, when the shift logic is reversed according to the manufacturer's request, for example, the oscillation frequency is set when the shift control signal is below a predetermined value. If you want to make it bigger, etc.
It is necessary to study the circuit once.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is to re-execute a circuit even if a positive voltage or a negative voltage of a shift control signal is selected at a shift terminal. It is an object of the present invention to provide a frequency shift type high frequency voltage controlled oscillator circuit which can be easily controlled without any investigation.

[0013]

The present invention includes a strip line, a variable capacitance diode, and a capacitor, and adjusts an inductive component of the variable capacitance diode by a first control voltage supplied to the variable capacitance diode. A resonance circuit section for controlling a resonance frequency, a negative resistance circuit section including an oscillation transistor for outputting an oscillation signal based on the resonance frequency of the resonance circuit section, and an amplification circuit section including a transistor for amplifying the oscillation signal. A high frequency voltage controlled oscillator circuit of the frequency shift type, wherein the anode of the variable capacitance diode is grounded via a second strip line, and a switching diode is arranged in parallel with the second strip line. A shift control terminal for supplying a shift control signal to one end of the switching diode and a DC voltage to the other end. A frequency shifting high-frequency voltage-controlled oscillator circuit, characterized in that the direct-voltage terminal for supplying provided respectively.

A resistor for adjusting the voltage of the shift control signal is arranged between one end of the switching diode and the shift control terminal, and a DC voltage is adjusted between the other end of the switching diode and the DC voltage terminal. A resistor is arranged, and a voltage dividing resistor is arranged between a connection point between the other end of the switching diode and the resistor connected to the other end of the switching diode and the ground potential.

[0015]

As described above, the potential applied to the cathode of the switching diode can be arbitrarily determined by the DC voltage and the shift control terminals supplied to both ends of the switching diode. This allows the voltage applied to the switching diode to be adjusted freely.

That is, the switching diode is short-circuited when the potential applied to the cathode of the switching diode is higher than the potential applied to the anode. Also,
The opposite is open. Therefore, when the switching diodes are connected in the opposite direction, the same shift control signal can be used to invert the impedance direction. Therefore, it is easy to turn on and off the switching diode.
High and low frequency band by FF control (shift amount shift)
Can be freely designed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The frequency shift type high frequency voltage controlled oscillator circuit of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a high frequency component incorporating the frequency shift type high frequency voltage controlled oscillation circuit of the present invention. That is,
In the high frequency component, in addition to the frequency shift type high frequency voltage controlled oscillation circuit, for example, a reception circuit of a communication circuit, a transmission circuit of the communication circuit, an antenna switch circuit, various filter parts, etc. are formed inside and on the surface of the multilayer circuit board. In FIG.
On the surface of the multilayer substrate 10, in addition to the predetermined surface wiring pattern 11 including an inductor conductor and a strip line, circuit components 12 such as a switching diode, a varicap diode, and a resistor that form a voltage controlled oscillator and other circuits are formed. Although not shown, inside the multilayer substrate, in addition to the internal wiring pattern and via-hole conductors, strip lines, microstrip lines, and ground potential conductor films that serve as capacitance electrodes and inductor conductors forming various capacitors are formed. .

On the end face of such a multi-layer substrate 10, terminal electrodes 13 which are terminals of various circuits are formed. The terminal electrode 13 includes a power supply voltage terminal, a ground potential terminal, a shift control terminal, a DC voltage terminal, and the like. It should be noted that various circuits formed on the multilayer substrate 1 and connection of each circuit in the multilayer substrate add, for example, an antenna terminal electrode, a reception signal output terminal, a transmission signal input terminal, and the like.

The frequency shift type high frequency voltage control type oscillation circuit formed on the multilayer circuit board 10 has a circuit as shown in FIG.

The frequency shift type high frequency voltage controlled oscillator circuit of FIG. 2 is a high frequency voltage controlled oscillator circuit in which a direc-conversion type IC can correspond to the control IC of the receiving circuit. That is, a part of the two frequency bands changed by the shift control is overlapped, and as a result, voltage control in a wide frequency band is enabled.

In FIG. 2, X is a resonance circuit section and Y
Is a negative resistance circuit section, and Z is an amplifier circuit section.

The resonant circuit section X includes a strip line SL, a variable capacitance diode DV that operates inductively, and
It is composed of capacitors C1, C2, C3 and an inductor element L1. In addition, a strip line S
Ls1, switching diode Di, capacitor Cs
1, a shift circuit including Cs2 and resistors Rs1 to Rs3 is added.

Further, the shift circuit portion is provided with a first terminal (shift control terminal) Vs and a second terminal (DC voltage terminal) Vc to which a voltage for turning ON / OFF the switching diode Di is supplied. Has been.

The negative resistance circuit section Y includes an oscillating transistor Tr1, various capacitors C5 to C7, and various resistors R1 to R.
2 and.

The amplifier circuit section Z is composed of an amplifying transistor Tr2, various capacitors C8 to C11, a resistor R3, and an inductance element L2.

In such a frequency shift type high frequency voltage controlled oscillator circuit, a Colpitts circuit for grounding the collector of the oscillating transistor Tr1 of the negative resistance circuit section Y in high frequency is used to satisfy the oscillation condition. The resonance circuit unit X is connected to the negative circuit unit with a coupling capacitor to oscillate. Then, this oscillation signal is transmitted to the amplification transistor Tr2.
Is output to and output from the output Mizuko OUT. Then, by applying a predetermined voltage that changes continuously or at minute intervals from the outside, it is possible to control the inductivity of the variable capacitance diode DV of the resonance circuit and the operating inductor component, and thereby the resonance in the resonance circuit. The frequency can be changed, so that the oscillation frequency can be continuously or extremely fluctuated, and an oscillation output that continuously changes as a whole can be obtained.

In the shift circuit, the strip line SLs1 is arranged between the anode of the variable capacitance diode DV and the ground potential, and the variable capacitance diode DV and the strip line SLs1 are shifted from the connection point via the capacitor Cs1 and the resistor Rs1. It is connected to the control terminal Vs.
Further, a switching diode Di and a capacitor C are provided between the connection point of the capacitor Cs1 and the resistor Rs1 and the ground potential so as to be in parallel with the strip line SLs1.
s2 is arranged. In FIG. 2, the cathode side of the switching diode Di is connected to the ground potential via the capacitor Cs2. A DC voltage terminal Vc is connected to a connection point between the cathode of the switching diode Di and the capacitor Cs2 via a resistor Rs2. Furthermore, a resistor Rs3 is provided in parallel with the capacitor Cs2.
Are arranged.

In such a circuit, for example, the DC voltage applied to the DC voltage terminal Vc is fixed at 2.8V,
The shift control signal supplied from the shift control terminal Vs is H at 2.8V and L at 0V. In FIG. 2, the resistance R
When s3 is 0Ω, the cathode of the switching diode Di is 0v. At this time, when the shift control signal of the shift control terminal Vs is H, the switching diode Di
Shorts. That is, at this time, the circuit becomes the same as that of FIG.

That is, when the shift control signal is H, the potential on the anode side of the switching diode Di is higher than that on the cathode side of the switching diode Di.
Is short-circuited and an on-inductor component of the switching diode Di is generated. As a result, the oscillation frequency band can be shifted to the higher side.

When the shift control signal is 0V, the potential of the anode of the switching diode Di is lower than that of the cathode of the switching diode Di.
i becomes open. As a result, the composite inductor component of the resonance circuit is composed of the strip line SL, the variable capacitance diode DV that operates inductively, and the strip line SLs1, and as a result, the oscillation frequency band can be shifted to the lower side. That is, if the shift control signal is H and the oscillation frequency can be shifted to the higher frequency band side, the shift control signal is L and the oscillation frequency can be moved to the lower frequency band side.

Further, as shown in FIG. 3, the switching diode Di is connected in the opposite direction. When this shift control signal is H, the switching diode D has a high potential on the cathode side, so that the switching diode D
i becomes open. On the contrary, when the shift control signal is L, the switching diode Di is short-circuited because the anode side of the switching diode Di has a high potential.

That is, the case described with reference to FIG. 2 is the occurrence of the on-inductor component when the H / L of the shift control signal is inverted, which is the opposite.

Therefore, if the shift control signal is L and the oscillation frequency can be shifted to the higher frequency band side, the shift control signal is H and the oscillation frequency can be moved to the lower frequency band side. Thus, when the shift control signal is H, the shift control signal is shifted to a high frequency band by the device incorporating the frequency shift type high frequency voltage controlled oscillation circuit, and the shift control signal becomes L when the shift control signal is H.
At that time, it is possible to easily cope with a request such as a case of shifting to a higher frequency band.

In the above description, the connection direction of the switching diode Di is focused on, but for example, the circuit configuration of the frequency shift type high frequency voltage controlled oscillator circuit (the connection direction of the switching diode is fixed, for example, as shown in FIG. 2). If the shift control terminal is set to the cathode side of the switching diode and the DC voltage terminal to which the DC voltage is supplied to the anode side is set,
In the case of shifting to a high frequency band, or when the shift control signal is L, it is possible to easily cope with a request such as shifting to a high frequency band.

[0036]

According to the present invention, even if either the positive voltage or the negative voltage of the shift control signal is selected for the shift control terminal,
A frequency shift type high frequency voltage controlled oscillator circuit that can easily cope with the control can be obtained without re-examination of the circuit.

[Brief description of drawings]

FIG. 1 is an external perspective view of a high frequency component including a frequency shift type high frequency voltage controlled oscillator circuit of the present invention.

FIG. 2 is a circuit diagram of a frequency shift type high frequency voltage controlled oscillator circuit of the present invention.

FIG. 3 is a partial circuit diagram of another frequency shift type high frequency voltage controlled oscillator circuit according to the present invention.

FIG. 4 is a circuit diagram of a conventional voltage controlled oscillator circuit.

FIG. 5 is a circuit diagram of a resonance circuit unit of a conventional frequency shift type voltage controlled oscillator circuit.

[Explanation of symbols]

X resonance circuit section Y Negative resistance circuit part Z amplifier circuit section DV First variable capacitance diode S shift circuit VS shift control signal VC bias voltage

Claims (2)

[Claims] 1. A resonance circuit including a strip line, a variable capacitance diode, and a capacitor, wherein a resonance frequency is controlled by adjusting an inductive component of the variable capacitance diode by a first control voltage supplied to the variable capacitance diode. Frequency shift type high frequency voltage control including a negative resistance circuit section including an oscillation transistor that outputs an oscillation signal based on the resonance frequency of the resonance circuit section, and an amplification circuit section including a transistor that amplifies the oscillation signal. An oscillation circuit, wherein the anode of the variable capacitance diode is grounded via a second strip line, a switching diode is arranged in parallel with the second strip line, and the one end of the switching diode is shifted. A shift control terminal that supplies a control signal and a DC voltage terminal that supplies a DC voltage to the other end Frequency shifting high-frequency voltage-controlled oscillator circuit characterized in that provided. 2. A resistor for adjusting the voltage of the shift control signal is arranged between one end of the switching diode and the shift control terminal, and a DC voltage is provided between the other end of the switching diode and the DC voltage terminal. A resistor for adjusting the voltage is arranged, and a voltage dividing resistor is arranged between the ground potential and the connection point between the other end of the switching diode and the resistor connected to the other end of the switching diode. 2. The frequency shift type high frequency voltage controlled oscillator circuit according to claim 1.