JP3028070B2 - Voltage controlled oscillator - Google Patents

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, and more particularly, to a ring oscillator constituted by bipolar transistors in the field of LSI.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an example of the configuration of a conventional voltage controlled oscillator composed of an odd number of stages of inverter circuits.

As shown in FIG. 7, the conventional example is constituted by connecting a plurality of inverter circuits 110-1 to 110- (2N + 1) (N is an integer) in an odd number of stages. 110- (2N + 1) includes differential input terminals V1 and V2, differential output terminals O1 and O2 from which signals input from the differential input terminals V1 and V2 are inverted and output, and an inverter circuit 110- (2N + 1). 1-110-
And a control terminal IN1 to which a control signal for controlling a current flowing in (2N + 1) is input. Then, the differential output terminal O of the preceding inverter circuit
1 and O2 are connected so that the signals output from them are input to the differential input terminals V1 and V2 of the next-stage inverter circuit, respectively. Also, the final stage inverter circuit 110-
The signals output from the (2N + 1) differential output terminals O1 and O2 are connected so as to be input to the differential input terminals V1 and V2 of the first stage inverter circuit 110-1.

FIG. 8 shows an inverter circuit 11 shown in FIG.
FIG. 3 is a circuit diagram illustrating a configuration of 0-1 to 110- (2N + 1). The inverter circuits 110-1 to 110- (2N
In (+1), all have the same configuration.

The conventional inverter circuit 110-
As shown in FIG. 8, 1-110- (2N + 1) has a resistor R1 having one end connected to the power supply voltage _Vcc and the other end connected to the differential output terminal O1, and a collector terminal connected to the power supply via the resistor R1. Voltage _Vcc , and the base terminal is the differential input terminal V
1 and a power supply voltage V at one end.
_cc , the other end of which is connected to the differential output terminal O2, and the collector terminal is connected to the power supply voltage V via the resistor R2.
connected to _cc, and connected transistors Q2 base terminal to the differential input terminal V2, resistor one end of which is grounded R3
And a transistor Q3 whose emitter terminal is grounded via a resistor R3 and whose base terminal is connected to the control terminal IN1. The emitter terminal of the transistor Q1, the emitter terminal of the transistor Q2, and the transistor Q3
Are connected to each other.

Hereinafter, the operation of the voltage controlled oscillator configured as described above will be described.

When a differential signal is input to differential input terminals V1 and V2 of inverter circuit 110-1, differential input terminal V
1 and V2 are inverted and output from differential output terminals O1 and O2 of inverter circuit 110-1.

The signals output from the differential output terminals O1 and O2 of the inverter circuit 110-1 are
-2 are input to the differential input terminals V1 and V2, respectively, inverted by the inverter circuit 110-2, and output from the differential output terminals O1 and O2 of the inverter circuit 110-2.

Then, similarly, the inverter circuit 110-
The signals output from the differential output terminals O1 and O2 of the inverter circuit 110-3 are input to the differential input terminals V1 and V2 of the inverter circuit 110-3 and inverted by the inverter circuit 110-3. Dynamic output terminal O
1, O2.

Thus, the inverter circuit 110- (2)
N + 1) until the differential output terminal O of the preceding inverter circuit
1 and O2 are input to differential input terminals V1 and V2 of the next-stage inverter circuit, respectively.

The signals output from the differential output terminals O1 and O2 of the inverter circuit 110- (2N + 1) are output as oscillation signals from the oscillation output terminals OUT1 and OUT2 and the differential input terminals of the inverter circuit 110-1. V
1 and V2.

In this manner, the signals output from the differential output terminals O1 and O2 of the final-stage inverter circuit 110- (2N + 1) are respectively applied to the differential input terminals V1 and V2 of the first-stage inverter circuit 110-1. An oscillation operation is obtained by inputting.

Here, the oscillation frequency in the oscillation operation is
The signal transmission delay time per one stage of the inverter circuit and the number of connected stages of the inverter circuit are determined by the control terminal of each of the inverter circuits 110-1 to 110- (2N + 1). IN1
Are controlled by the voltage value of the control signal input to

When the voltage of the control signal is increased, the current flowing through the inverter circuit is increased, and the signal transmission delay time per one stage of the inverter circuit is shortened, whereby the oscillation frequency is increased.

On the other hand, when the voltage of the control signal is lowered, the current flowing through the inverter circuit decreases, and the voltage of the inverter circuit decreases.
The signal voltage delay per stage is longer,
The oscillation frequency decreases.

However, when the oscillation frequency is lowered,
Since the value of the current flowing through the inverter circuit decreases, the output amplitude decreases, and a sufficient output amplitude cannot be obtained from the oscillation output terminals OUT1 and OUT2.

When the oscillation frequency is increased, the value of the current flowing through the inverter circuit increases, and the amplitude of the signal output from the differential output terminals O1 and O2 of the inverter circuit increases. The transistors Q1 and Q2 of the circuit become saturated, and the transistors do not operate.

As described above, the conventional voltage controlled oscillator as shown in FIG. 7 cannot oscillate a wide range of frequencies.

Therefore, Japanese Unexamined Patent Publication No. 7-254847 discloses an odd-numbered inverter circuit of a plurality of connected inverter circuits so that the number of connected inverter circuits constituted by MOSFETs can be selected according to the oscillation frequency. A circuit is disclosed in which a signal is extracted from an output terminal of the inverter circuit, and the extracted signal is negatively fed back to an input terminal of a first-stage inverter circuit via a selection circuit to oscillate.

When a low frequency is oscillated using the circuit described above, oscillation is performed using a large number of inverter circuits, and when a high frequency is oscillated, oscillation is performed using a small number of inverter circuits. Thus, it is possible to prevent a change in the output amplitude value due to the oscillation frequency.

Japanese Patent Application Laid-Open No. 6-61800 discloses that
There is disclosed a circuit that prevents a change in output amplitude value due to an oscillation frequency by selecting a resistance value corresponding to a current value flowing through an inverter circuit.

FIG. 9 is a block diagram showing the configuration of the voltage controlled oscillator disclosed in Japanese Patent Application Laid-Open No. 6-61800, and FIG. 10 is a circuit diagram showing the configuration of the inverter circuit shown in FIG.

As shown in FIGS. 9 and 10, the voltage controlled oscillator disclosed in Japanese Patent Application Laid-Open No. 6-61800 has resistors R1 and R2 shown in FIG.
The load control circuit 215 for controlling the resistance values of the variable resistors R4 and R5 is provided.

In the voltage controlled oscillator configured as described above, the load control circuit
A control signal based on the current flowing through 10-1 to 210- (2N-1) is output, and the resistance value of the variable resistors R4 and R5 is controlled by the control signal. The change is prevented.

[0025]

However, the above-mentioned conventional voltage controlled oscillator has the following problems.

(1) In the device disclosed in Japanese Patent Application Laid-Open No. 7-254847, a selection circuit for selecting an output signal of an odd-numbered inverter circuit must be provided. And the current consumption by the selection circuit increases.

Further, since the inverter circuit is composed of MOSFETs, the output amplitude becomes a potential difference (large amplitude) between the power supply and the ground, and noise countermeasures are required.

(2) In the device disclosed in JP-A-6-61800, a load control circuit for controlling the resistance value of the variable resistor in the inverter circuit must be provided. In addition to an increase in cost, current consumption by the selection circuit increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional technology, and has a circuit for selecting an output signal of a circuit and controlling a resistance value in the circuit. It is another object of the present invention to provide a voltage controlled oscillator capable of performing an oscillation operation in which the output amplitude value is constant.

[0030]

In order to achieve the above object, the present invention provides a first and second differential input terminals and a signal input from the first and second differential input terminals, respectively. Second and first differential output terminals 1 that are output in the forward direction,
A differential circuit in which first and second control signals for controlling a current flowing inside are differentially input to each other is a voltage-controlled oscillator in which a plurality of stages are connected, and each of the differential circuits includes: A first transistor having a collector terminal connected to the first differential output terminal, connected to a power supply voltage via a first resistor, and a base terminal connected to the first differential input terminal; A second transistor having a collector terminal connected to the second differential output terminal, connected to a power supply voltage via a second resistor, and a base terminal connected to the second differential input terminal; An emitter terminal is grounded via a third resistor, a third transistor whose base terminal receives the first control signal, and a base terminal connected to a collector terminal of the second transistor,
A fourth transistor having a collector terminal connected to the collector terminal of the first transistor, a base terminal connected to the collector terminal of the first transistor, and a collector terminal connected to the collector terminal of the second transistor. A fifth transistor and an emitter terminal connected to the third transistor.
A sixth transistor to which the second control signal is input to a base terminal, and an emitter terminal of the first transistor, an emitter terminal of the second transistor, The collector terminal of the third transistor is connected to each other, and the emitter terminal of the fourth transistor, the emitter terminal of the fifth transistor, and the collector terminal of the sixth transistor are connected to each other. .

Further, the first and second differential input terminals, and the second and first differential output terminals from which the signals input from the first and second differential input terminals are output in normal rotation, respectively. 1 and a first and a second for controlling a current flowing through the inside.
Is a voltage-controlled oscillator in which a plurality of differential circuits to which the control signals are differentially inputted are connected in a plurality of stages, and each of the differential circuits has a collector terminal connected to the first differential output terminal. A first transistor having a base terminal connected to the first differential input terminal, a collector terminal connected to the second differential output terminal, and a first transistor having a base terminal connected to the first differential input terminal. A second transistor having a base terminal connected to the second differential input terminal, a second transistor connected to the power supply voltage via a second resistor, an emitter terminal grounded, and a first control terminal connected to the base terminal. A third transistor to which a signal is input, and a fourth transistor having a base terminal connected to the collector terminal of the second transistor and a collector terminal connected to the collector terminal of the first transistor A fifth transistor having a base terminal connected to the collector terminal of the first transistor, a collector terminal connected to the collector terminal of the second transistor, an emitter terminal grounded, and a second terminal connected to the base terminal. A sixth transistor to which a control signal is input, wherein an emitter terminal of the first transistor, an emitter terminal of the second transistor, and a collector terminal of the third transistor are connected to each other; The emitter terminal of the transistor, the emitter terminal of the fifth transistor, and the collector terminal of the sixth transistor are connected to each other.

Further, the first and second differential input terminals, and the second and first differential output terminals from which the signals input from the first and second differential input terminals are output in the forward direction, respectively. 1 and a first and a second for controlling a current flowing through the inside.
Is a voltage-controlled oscillator in which a plurality of differential circuits to which differential control signals are differentially input are connected in a plurality of stages, wherein each of the differential circuits has a predetermined voltage applied to a base terminal and an emitter terminal grounded. And a collector terminal connected to the first differential output terminal, connected to a power supply voltage via a first resistor, and a base terminal connected to the first differential input terminal. A first transistor and a collector terminal connected to the second differential output terminal and connected to a power supply voltage via a second resistor;
A second terminal having a base terminal connected to the second differential input terminal;
, A third transistor having an emitter terminal connected to the collector terminal of the seventh transistor, a base terminal receiving the first control signal, and a base terminal connected to the collector terminal of the second transistor. And
A fourth transistor having a collector terminal connected to the collector terminal of the first transistor, a base terminal connected to the collector terminal of the first transistor, and a collector terminal connected to the collector terminal of the second transistor. And a sixth transistor having an emitter terminal connected to the collector terminal of the seventh transistor, and a base terminal receiving the second control signal. A terminal, an emitter terminal of the second transistor, and a collector terminal of the third transistor are connected to each other, and an emitter terminal of the fourth transistor, an emitter terminal of the fifth transistor, and a collector of the sixth transistor. The terminals are connected to each other.

The differential circuit has 2n stages (n is an integer)
The output from the differential circuit at the last stage and the output from the differential circuit at the n-th stage are output as oscillation outputs.

(Function) In the present invention configured as described above, when the oscillation frequency is increased, the current flowing through the first to third transistors is increased by increasing the voltage of the first control signal. As a result, the signal transmission delay time per one stage of the differential circuit is reduced, and the oscillation frequency is increased. However, when the voltage of the first control signal is increased, the signal is differentially input to the first control signal. Since the voltage of the second control signal decreases by an amount corresponding to the increase in the voltage of the first control signal,
The current flowing through the sixth transistor decreases by an increase in the current flowing through the third transistor, and the current flowing through the fourth and fifth transistors decreases by the increase of the current flowing through the first and second transistors. . Thereby, even when the voltage of the first control signal is increased,
The value of the current flowing per differential circuit does not change.

Therefore, even when the oscillation frequency of the voltage controlled oscillator is increased, the output amplitude value of the voltage controlled oscillator does not change.

In order to lower the oscillation frequency, the first
If the voltage of the control signal is reduced, the current flowing through the first to third transistors decreases, thereby increasing the signal transmission delay time per stage of the differential circuit and lowering the oscillation frequency. When the voltage of the first control signal is reduced, the voltage of the second control signal that is differentially input with respect to the first control signal increases by the amount corresponding to the decrease in the voltage of the first control signal. And the current flowing through the fourth and fifth transistors increases with the decrease in the current flowing through the third transistor.
Increases by the decrease in the current flowing through the transistor. Thus, even when the voltage of the first control signal is lowered, the value of the current flowing per stage of the differential circuit does not change.

Therefore, even when the oscillation frequency of the voltage controlled oscillator is lowered, the output amplitude value of the voltage controlled oscillator does not change.

[0038]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the voltage controlled oscillator according to the present invention.

In this embodiment, as shown in FIG. 1, a plurality of differential circuits 10-1 to 10-n (n is an integer of 2 or more) are connected in integer stages, and each differential circuit 10- 1-10-
n denotes first and second differential input terminals V1 and V2 and second and first differential output terminals O2 and N2 to which signals input from the differential input terminals V1 and V2 are non-inverted and output, respectively. O1
And a control terminal IN1 to which a first control signal for controlling a current flowing in the differential circuits 10-1 to 10-n is input.
And a control terminal IN2 to which a second control signal is input. The signals are output from the differential output terminals O1 and O2 of the preceding differential circuit so as to be input to the differential input terminals V2 and V1, respectively, of the next differential circuit. Also, the final stage differential circuit 10-n
Are connected such that signals output from the differential output terminals O1 and O2 are input to the differential input terminals V1 and V2 of the differential circuit 10-1 at the forefront stage, respectively. Note that the first control signal and the second control signal are differentially input to each other.

FIG. 2 shows the differential circuits 10-1 to 10-1 shown in FIG.
FIG. 10 is a circuit diagram illustrating a configuration example of 10-n. The differential circuits 10-1 to 10-n have the same configuration.

In this configuration example, as shown in FIG. 2, a first resistor R1 having one end connected to the power supply voltage _Vcc and the other end connected to the differential output terminal O1, and a collector terminal connected via the resistor R1. It is connected to the power supply voltage V _cc Te, a first transistor Q1 whose base terminal is connected to the differential input terminals V1, one end connected to power supply voltage V _cc, the other end connected to the differential output terminal O2 A second resistor R2, a second transistor Q2 having a collector terminal connected to the power supply voltage _Vcc via the resistor R2 and a base terminal connected to the differential input terminal V2, and a third transistor Q2 having one end grounded. The resistor R3 and the emitter terminal are the resistor R3
A third transistor Q3 whose base terminal is connected to the control terminal IN1 and a fourth transistor whose base terminal is connected to the collector terminal of the transistor Q2 and whose collector terminal is connected to the collector terminal of the transistor Q1. The transistor Q4 has a base terminal connected to the collector terminal of the transistor Q1, and a collector terminal connected to the transistor Q1.
Fifth transistor Q5 connected to the collector terminal of the second transistor Q5
And a sixth transistor Q6 whose emitter terminal is grounded via a resistor R3 and whose base terminal is connected to a control terminal IN2. The sixth transistor Q6 has an emitter terminal of the transistor Q1, an emitter terminal of the transistor Q2, and a third transistor Q3. The collector terminal is connected to each other, and the emitter terminal of transistor Q4, the emitter terminal of transistor Q5, and the collector terminal of transistor Q6 are connected to each other.

The operation of the voltage controlled oscillator configured as described above will be described below.

The differential input terminals V1, V of the differential circuit 10-1
2, when a differential signal is input to differential input terminals V1, V2
Are output from the differential output terminals O2 and O1 of the differential circuit 10-1 in normal rotation.

The differential output terminals O1, O of the differential circuit 10-1
2 are respectively input to the differential input terminals V2 and V1 of the differential circuit 10-2, and are normally output from the differential output terminals O1 and O2 of the differential circuit 10-2.

Similarly, signals output from differential output terminals O1 and O2 of differential circuit 10-2 are applied to differential circuit 10-2.
-3 differential input terminals V2 and V1, respectively, and are output from the differential output terminals O1 and O2 of the differential circuit 10-3 in the normal rotation.

As described above, up to the differential circuit 10-n, the signals output from the differential output terminals O1 and O2 of the preceding differential circuit are applied to the differential input terminals V2 and V1 of the next differential circuit. Each is entered.

The differential output terminals O1, O of the differential circuit 10-n
2 are output from the oscillation output terminals OUT2, OU
The signal is output from T1 as an oscillation signal, and is also input to the differential input terminals V1 and V2 of the differential circuit 10-1.

Thus, the final stage differential circuit 10-
The oscillation operation is obtained by inputting the signals output from the n differential output terminals O1 and O2 to the differential input terminals V1 and V2 of the foremost differential circuit 10-1.

Here, the oscillation frequency in the oscillation operation is
The signal transmission delay time per stage of the differential circuit and the number of connection stages of the differential circuit are determined by the signal transmission delay time per stage of the differential circuit. It is controlled by the voltage values of the first and second control signals input to the control terminals IN1 and IN2.

When the voltage of the first control signal input to the control terminal IN1 is increased, the current flowing through the transistor Q3 increases, and the current flowing through the transistors Q1 and Q2 also increases. Therefore, the signal transmission delay time per one stage of the differential circuit is reduced, and the oscillation frequency is increased.

Here, the second input to the control terminal IN2
Is input differentially with respect to the first control signal input to the control terminal IN1, and when the voltage of the first control signal input to the control terminal IN1 is increased, the control signal IN2 is input to the control terminal IN2. The voltage of the second control signal is reduced by an amount corresponding to the increase in the voltage of the first control signal. for that reason,
When the voltage of the first control signal input to the control terminal IN1 is increased, the current flowing through the transistor Q6 is reduced by the increase in the current flowing through the transistor Q3, and the current flowing through the transistors Q4 and Q5 is reduced by the transistors Q1 and Q5.
2 decreases by the amount of increase in the current flowing through 2.

Thus, even when the voltage of the first control signal input to the control terminal IN1 is increased, the value of the current flowing per stage of the differential circuit does not change.

Therefore, even when the oscillation frequency of the voltage controlled oscillator is increased, the output amplitude value of the voltage controlled oscillator does not change.

When the voltage of the first control signal input to the control terminal IN1 is lowered, the current flowing through the transistor Q3 is reduced, so that the transistors Q1 and Q2
The current flowing through is also reduced. Therefore, the signal transmission delay time per one stage of the differential circuit becomes longer, and the oscillation frequency becomes lower.

Here, the second signal input to the control terminal IN2 is
Is input differentially with respect to the first control signal input to the control terminal IN1, and when the voltage of the first control signal input to the control terminal IN1 is lowered, the control signal The voltage of the second control signal is increased by an amount corresponding to the decrease in the voltage of the first control signal. for that reason,
When the voltage of the first control signal input to the control terminal IN1 is reduced, the current flowing through the transistor Q6 increases by a decrease in the current flowing through the transistor Q3, and the current flowing through the transistors Q4 and Q5 increases.
2 is increased by the amount of decrease in the current flowing therethrough.

Thus, even when the voltage of the first control signal input to the control terminal IN1 is lowered, the value of the current flowing per stage of the differential circuit does not change.

Therefore, even when the oscillation frequency of the voltage controlled oscillator is lowered, the output amplitude value of the voltage controlled oscillator does not change.

FIG. 3 shows the differential circuits 10-1 to 10-1 shown in FIG.
FIG. 10 is a circuit diagram illustrating another configuration example of 10-n.

In this configuration example, as shown in FIG. 3, the resistor R3 is not provided for the one shown in FIG. 2, and the emitter terminals of the transistors Q3 and Q6 are directly grounded.

In the differential circuit as shown in FIG.
Since the emitter terminals of the transistors Q3 and Q6 are directly grounded, the power supply voltage _Vcc can be reduced by the voltage drop of the resistor R3 shown in FIG. 2, and the voltage controlled oscillator can be operated at a low voltage. it can.

FIG. 4 shows the differential circuits 10-1 to 10-1 shown in FIG.
FIG. 10 is a circuit diagram illustrating another configuration example of 10-n.

In this configuration example, as shown in FIG. 4, a transistor Q7 is provided instead of the resistor R3 shown in FIG. 2, and the emitter terminal of the transistor Q7 is grounded. A constant voltage is applied to the base terminal, and the collector terminals are connected to the transistors Q3 and Q6.
Connected to the emitter terminal.

In the voltage controlled oscillator shown in FIG. 4, a transistor Q7 provided between the emitter terminals of transistors Q3 and Q6 and the ground functions as a constant current source, and is similar to that shown in FIG. The result is obtained. In addition, if a band gap reference voltage having a small voltage change with respect to a temperature change is applied to the base terminal, the oscillation frequency does not change due to the ambient temperature.

(Other Embodiment) FIG. 5 is a block diagram showing another embodiment of the voltage controlled oscillator of the present invention.
FIG. 6 is a diagram showing an oscillation waveform output from the voltage controlled oscillator shown in FIG. In this embodiment, 90
A degree difference signal is output.

In this embodiment, as shown in FIG. 5, the differential circuits shown in FIG. 1 are connected in four stages.
-2 differential output terminals O1 and O2 output signals
The signals are input to the differential input terminals V2 and V1 of the third-stage differential circuit 10-3, respectively, and the oscillation output terminals OUT4 and OUT4 are output.
It is configured to be output from OUT3 as an oscillation signal. Then, similarly to the voltage-controlled oscillator shown in FIG. 1, the signals output from the differential output terminals O1 and O2 of the differential output circuit of the final-stage differential circuit 10-4 are output from the oscillation output terminals OUT2 and OUT1. The signal is output as an oscillation signal, and is also input to differential input terminals V1 and V2 of the differential circuit 10-1.

In the voltage-controlled oscillator configured as described above, as shown in FIG.
The phase difference between the signals output from the differential output terminals O1 of the differential circuit 10-4 is 0 degrees when the phase of the signal output from the differential output terminal O1 of the differential circuit 10-4 is 0 degree.
The phase difference between the signals output from the differential output terminal O1 is 45
The phase difference of the signal output from the differential output terminal O1 of the differential circuit 10-2 is 90 degrees, and the phase difference of the signal output from the differential output terminal O1 of the differential circuit 10-1 is 135 degrees. Become.

As a result, the oscillation output terminals OU connected to the differential output terminals O1 and O2 of the differential circuit 10-4, respectively.
The signal output from T2 and OUT1 and the differential circuit 10-
The phase difference between the signals output from the oscillation output terminals OUT4 and OUT3 connected to the two differential output terminals O1 and O2 is 90 degrees. Similarly, the differential circuit 10-1
And the signals output from the differential output terminals O1 and O2 of the differential circuit 10-3 also have a phase difference of 90 degrees.

The 90-degree phase difference signal output from the above-described voltage-controlled oscillator is used as a local signal of a quadrature modulation type modulator in the field of wireless communication.

Further, in the present embodiment, the number of differential circuits to be connected is four, but the present invention is not limited to this, and a plurality of differential circuits are connected, and the final differential circuit is connected. , And an output signal from an intermediate stage (nth stage if the total number of stages is 2n), a signal having a phase difference of 90 degrees can be obtained.

[0071]

As described above, in the present invention,
Each of the differential circuits connected in a plurality of stages has first and second
Are input differentially to each other, and the first to third transistors whose driving is controlled by the first control signal and the fourth to sixth transistors whose driving is controlled by the second control signal Therefore, even when the oscillation frequency of the voltage controlled oscillator is increased or decreased,
The current flowing per one stage of the differential circuit does not change, and the output amplitude value of the voltage controlled oscillator does not change.

Thus, an oscillation operation in which the output amplitude value is constant can be performed without providing a circuit for selecting an output signal or controlling an internal resistance value.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a voltage controlled oscillator according to the present invention.

FIG. 2 is a circuit diagram illustrating a configuration example of a differential circuit illustrated in FIG. 1;

FIG. 3 is a circuit diagram showing another configuration example of the differential circuit shown in FIG. 1;

FIG. 4 is a circuit diagram showing another configuration example of the differential circuit shown in FIG. 1;

FIG. 5 is a block diagram showing another embodiment of the voltage controlled oscillator of the present invention.

FIG. 6 is a diagram showing an oscillation waveform output from the voltage controlled oscillator shown in FIG.

FIG. 7 is a block diagram showing an example of the configuration of a conventional voltage-controlled oscillator composed of odd-numbered stages of inverter circuits.

8 is a circuit diagram showing a configuration of the inverter circuit shown in FIG.

FIG. 9 is a block diagram showing a configuration of a voltage controlled oscillator disclosed in Japanese Patent Application Laid-Open No. 6-61800.

FIG. 10 is a circuit diagram showing a configuration of the inverter circuit shown in FIG. 9;

[Description of Signs] 10-1 to 10-n Differential circuit IN1, IN2 Control terminal O1, O2 Differential output terminal OUT1 to OUT4 Oscillation output terminal Q1 to Q7 Transistor R1, R2 Resistance V1, V2 Differential input terminal

Claims (4)

(57) [Claims] A first differential input terminal and a first differential input terminal;
And a second and a first differential output terminal 1 from which a signal input from the second differential input terminal is output in a non-inverted manner, respectively, for controlling a current flowing through the first and second differential output terminals. A voltage-controlled oscillator in which a plurality of differential circuits to which the control signals are differentially input are connected in a plurality of stages, wherein each of the differential circuits has a collector terminal connected to the first differential output terminal. A first transistor having a base terminal connected to the first differential input terminal, a collector terminal connected to the second differential output terminal, and a first transistor connected to a power supply voltage via a first resistor. A second transistor having a base terminal connected to the second differential input terminal, a second transistor connected to the power supply voltage via a second resistor, an emitter terminal grounded via a third resistor, Terminal receives the first control signal. A third transistor having a base terminal connected to the collector terminal of the second transistor, a fourth transistor having a collector terminal connected to the collector terminal of the first transistor, and a base terminal connected to the first transistor. A fifth transistor having a collector terminal connected to the collector terminal of the transistor, a collector terminal connected to the collector terminal of the second transistor, an emitter terminal grounded via the third resistor, and a second terminal connected to the base terminal. A sixth transistor to which a control signal is input, wherein an emitter terminal of the first transistor, an emitter terminal of the second transistor, and a collector terminal of the third transistor are connected to each other; The emitter terminal of the fifth transistor, the emitter terminal of the fifth transistor, and the emitter terminal of the sixth transistor. A voltage controlled oscillator, characterized in that the collector terminal are connected to each other. A first differential input terminal and a second differential input terminal;
And a second and a first differential output terminal 1 from which a signal input from the second differential input terminal is output in a non-inverted manner, respectively, for controlling a current flowing through the first and second differential output terminals. A voltage-controlled oscillator in which a plurality of differential circuits to which the control signals are differentially input are connected in a plurality of stages, wherein each of the differential circuits has a collector terminal connected to the first differential output terminal. A first transistor having a base terminal connected to the first differential input terminal, a collector terminal connected to the second differential output terminal, and a first transistor connected to a power supply voltage via a first resistor. A second transistor having a base terminal connected to the second differential input terminal, a second transistor connected to a power supply voltage via a second resistor, an emitter terminal grounded, and a first control terminal connected to the base terminal. The third transition to which the signal is input A fourth transistor having a collector, a base terminal connected to the collector terminal of the second transistor, a collector terminal connected to the collector terminal of the first transistor, and a base terminal connected to the collector terminal of the first transistor. A fifth transistor whose collector terminal is connected to the collector terminal of the second transistor, and a sixth transistor whose emitter terminal is grounded and whose base terminal receives the second control signal. The emitter terminal of the first transistor, the emitter terminal of the second transistor, and the collector terminal of the third transistor are connected to each other, and the emitter terminal of the fourth transistor and the fifth transistor are connected to each other. The emitter terminal and the collector terminal of the sixth transistor are connected to each other Voltage controlled oscillator according to claim. 3. The first and second differential input terminals and the first and second differential input terminals.
And a second and a first differential output terminal 1 from which a signal input from the second differential input terminal is output in a non-inverted manner, respectively, for controlling a current flowing through the first and second differential output terminals. A differential circuit in which the control signals are differentially input to each other are connected in a plurality of stages, and each of the differential circuits has a predetermined voltage applied to a base terminal and an emitter terminal grounded. And a collector terminal connected to the first differential output terminal, connected to a power supply voltage via a first resistor, and a base terminal connected to the first differential input terminal. And a collector terminal connected to the second differential output terminal, connected to a power supply voltage via a second resistor, and a base terminal connected to the second differential input terminal. A second transistor, A third transistor having an emitter terminal connected to the collector terminal of the seventh transistor, a base terminal receiving the first control signal, and a base terminal connected to the collector terminal of the second transistor; A fourth transistor connected to the collector terminal of the first transistor, a fourth transistor connected to the collector terminal of the first transistor, and a base terminal connected to the collector terminal of the second transistor. And a sixth transistor having an emitter terminal connected to the collector terminal of the seventh transistor and a base terminal receiving the second control signal, and an emitter terminal of the first transistor; The emitter terminal of the second transistor and the collector terminal of the third transistor are connected to each other. Is, the fourth voltage-controlled oscillator, characterized in that the emitter terminal and the emitter terminal of the fifth transistor and the collector terminal of the sixth transistor are connected to one another of the transistor. 4. The voltage controlled oscillator according to claim 1, wherein the differential circuit is connected in 2n stages (n is an integer), and an output from the final stage differential circuit is connected to the n stages. A voltage-controlled oscillator, wherein an output from a second differential circuit is output as an oscillation output.