JP3507697B2 - PLL type oscillation circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PLL (Ph) applied to, for example, a frequency synthesizer type high frequency modulator.
ase locked loop) type oscillator circuit.

[0002]

2. Description of the Related Art A PLL type oscillation circuit of this type has, for example, an oscillation circuit whose oscillation frequency changes according to an input current, a counter for dividing an output signal of the oscillation circuit, and a phase of an output signal of the counter. A phase comparison circuit that compares the phase of a reference signal, a charge pump circuit that converts the output signal of this phase comparison circuit, and a loop filter that is, for example, a low-pass filter that generates a control voltage from the output signal of this charge pump circuit. A current generation circuit that compares a control voltage output from the loop filter with a reference voltage to generate a control current, and a current transmission circuit that transmits the current output from the current generation circuit to the oscillation circuit. ing.

[0003]

The reference voltage generating circuit for generating the reference voltage supplied to the current generating circuit is composed of a constant current source and a diode and does not have power supply voltage dependency. Therefore, even when the power supply voltage changes, a constant reference voltage is generated.
However, the oscillating circuit and the current transmitting circuit for supplying the controlling current to the oscillating circuit are composed of bipolar transistors, and when the power supply voltage changes, the collector current changes due to the Early effect. Therefore, for example, when noise such as ripples is superimposed on the power supply voltage, the oscillation frequency changes.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a PLL type oscillation circuit capable of preventing a change in oscillation frequency even when a power supply voltage changes. Is to provide.

[0005]

[0006]

A PLL type oscillator circuit according to the present invention
In order to solve the above problems, the path is an oscillation circuit configured by a bipolar transistor whose oscillation frequency changes according to a change in input current, and a voltage generation circuit that generates a control voltage according to the oscillation frequency of the oscillation circuit. A reference voltage generating circuit that generates a reference voltage that changes according to fluctuations in the power supply voltage, a control voltage that is output from the voltage generating circuit, and a reference voltage that is generated by the reference voltage generating circuit. And a current transmission circuit configured to transmit a current output from the current generation circuit to the voltage controlled oscillation circuit.

Further, the PLL type oscillation circuit of the present invention comprises an oscillation circuit composed of a bipolar transistor whose oscillation frequency changes according to a change in input current, a counter for dividing an output signal of the oscillation circuit, A phase comparison circuit that compares the phase of the output signal of the counter with the phase of the reference signal, a charge pump circuit that converts the output signal of the phase comparison circuit, and a control voltage that is generated from the output signal of the charge pump circuit, for example, a low voltage. A loop filter including a band-pass filter, a reference voltage generation circuit that generates a reference voltage that changes according to fluctuations in the power supply voltage, a control voltage that is output from the loop filter, and a reference voltage that is generated by the reference voltage generation circuit. And a current generation circuit configured by a bipolar transistor that generates a control current. And comprising a current transfer circuit for transmitting a current to be output to the voltage controlled oscillation circuit.

The reference voltage generating circuit includes a constant current source connected in series between a power source and ground, an impedance circuit generating a voltage according to a flowing current, and a resistor connected in parallel to the constant current source. is doing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a PLL type oscillation circuit to which the present invention is applied. In FIG. 2, the oscillator circuit 11 is a circuit which is composed of bipolar transistors and whose oscillation frequency changes according to an input current. A counter 12 and a phase comparison circuit 1 are provided at the output end of the oscillation circuit 11.
3, the PLL circuit 15 including the charge pump circuit 14 is connected. The counter 12 divides the output signal of the oscillation circuit 11, and the phase comparison circuit 13 compares the phase of the output signal of the counter 12 with the phase of a reference signal (not shown).
The charge pump circuit 14 converts the output signal of the phase comparison circuit 13. The output signal of the charge pump circuit 14 is supplied to the loop filter 16 formed of, for example, a low pass filter. The loop filter 16 includes the charge pump circuit 1
A control voltage Vpll is generated from the output signal of No. 4. The control voltage Vpll output from the loop filter 16 is the reference voltage Vre of the power supply voltage supplied from the reference voltage generating circuit 17.
Along with f, a current generation circuit 1 including, for example, a differential amplifier
8 are supplied. The current generation circuit 18 controls the control voltage V
The control current is generated by comparing pll with the reference voltage Vref. The current output from the current generation circuit 18 is supplied to the oscillation circuit 11 via the current transmission circuit 19.

FIG. 1 shows a circuit configuration of a main part of FIG. 2, and the same parts as those in FIG. 1 are designated by the same reference numerals. The reference voltage generating circuit 17 includes a constant current source I1 connected in series between a power supply terminal 21 supplied with a power supply voltage Vcc and a ground terminal 22.
And a resistor R1 connected in parallel to the constant current source I1, for example, diode-connected NPN transistors Q1, Q2, Q3 forming an impedance circuit, and a connection node N of the constant current source I1 and the transistor Q1.
The reference voltage Vref is output from 1.

The current generation circuit 18 is a differential amplifier DF.
NPN transistors Q5 and Q8 forming A, and a resistor R
2, R3, a constant current source I4, and NPN transistors Q4 and Q6 forming the current mirror circuit CM1. The constant current source I4 and the current mirror circuit CM1 form a reference current section. That is, the reference voltage Vref is supplied to the base of the NPN transistor Q5. The collector of this transistor is connected to the power supply terminal 21, and the emitter is connected to one end of the resistor R2. A control voltage Vpll is applied to the base of the transistor Q8.
Is being supplied. The collector of the transistor Q8 is connected to the collector of a PNP transistor Q7 that constitutes the current transfer circuit 19, and the emitter is connected to one end of the resistor R3. One end of the constant current source I4 is connected to the power supply terminal 21, and the other end is connected to the collector and base of the transistor Q4 and the base of the transistor Q6.
The emitters of these transistors Q4 and Q6 are the ground terminal 2
2 and the collector of the transistor Q6 is connected to the other ends of the resistors R2 and R3.

The current transfer circuit 19 includes PNP transistors Q7, Q9, which form a current mirror circuit CM2.
And NPN transistors Q10, Q11 and Q12 which form the current mirror circuit CM3.
The emitters of the transistors Q7 and Q9 are power supply terminals 21.
, And each base is connected to the collector of the transistor Q7. The collector of the transistor Q9 is the collector of the transistor Q10 and the transistors Q10 and Q1.
1, commonly connected to the bases of Q12. The emitters of these transistors Q10, Q11, Q12 are connected to the ground terminal 22.

The oscillation circuit 11 is composed of an emitter-coupled astable multivibrator including NPN transistors Q13 to Q18, resistors R4, R5, R6, R7 and a capacitor C1, for example. That is, the collectors and bases of the transistors Q14 and Q17 are respectively connected to the power supply terminal 21, and the emitters are resistors R5 and R5.
Power source terminals 21 are connected via 6 respectively. The emitters of the transistors Q14 and Q17 are the bases of the transistors Q13 and Q18, and the transistor Q1.
5, Q16 connected to each collector. The collectors of the transistors Q13 and Q18 are connected to the power supply terminal 21. The emitter of the transistor Q13 is a resistor R
4 is connected to the ground terminal 22 through the transistor Q1
The emitter of 8 is connected to the ground terminal 22 via a resistor R7. The base of the transistor Q15 is connected to the emitter of the transistor Q18, and the base of the transistor Q16 is connected to the emitter of the transistor Q13. The emitter of the transistor Q15 is connected to the collector of the transistor Q11, and the emitter of the transistor Q16 is connected to the collector of the transistor Q12. Furthermore, the transistor Q15,
A capacitor C1 is connected between the emitters of Q16. The output signal VC1 of the oscillator circuit 11 is output from the collector of the transistor Q15.

A feature of the present invention is that the reference voltage generating circuit 17 has power supply voltage dependency. Therefore, in the circuit shown in FIG. 1, the resistor R1 is connected in parallel to the constant current source I1 as described above. FIG. 3 shows a circuit configuration using a conventional reference voltage generating circuit 23 having power supply voltage dependency, and the same parts as those in FIG. 1 are designated by the same reference numerals.

In the above structure, the operation of the circuit shown in FIG. 1 will be described in comparison with the operation of the circuit shown in FIG. For convenience of explanation, it is assumed that the current amplification factor of each transistor is infinite and the base current is zero.

In the conventional reference voltage generating circuit 23 shown in FIG. 3, three diode-connected transistors Q are provided.
Constant current is supplied to 1, Q2 and Q3 from the constant current source I1. The forward voltage Vf of each transistor is about 0.77
V. Therefore, the reference voltage generating circuit 23 has about 2.3
The reference voltage Vref of V is output. That is, the reference voltage V
ref is expressed by the following equation (1).

Vref = 3 × Vf (1) On the other hand, in the present embodiment shown in FIG. 1, the resistor R1 is connected in parallel to the constant current source I1. Therefore, when the power supply voltage Vcc changes, the value of the current flowing through the resistor R1 also changes, so the value of the current flowing through the diode also changes, and the output voltage changes. The standard value of the power supply voltage Vcc is the power supply voltage V
Assuming cc0, Vref = 3 × Vf + (3 × Re / (R1 + 3 × Re)) × (Vcc−Vcc0) (2) within the range in which the change amount of the reference voltage Vref is minute. Here, Vf is the forward voltage of the diode when the power supply voltage Vcc is the standard value Vcc0, and Re is the equivalent resistance at the operating points of the transistors Q1 to Q3, which is about 130Ω in this example. The equivalent resistance Re is expressed by the following equation.

Re = Vt / Ie, Vt = k × T / q (3) Here, Vt: thermal voltage, k: Boltzmann constant, Ie: diode current, T: absolute temperature, q: electron charge. .

The reference voltage Vref is centered at about 2.3 V and changes with the power supply voltage Vcc. The standard value of the power supply voltage Vcc is, for example, 5V. The current value of the constant current source I1 is set to 59 μA, for example. This is because the current values flowing from the transistor Q1 to the transistor Q3 are both 200 μA so that the reference voltage Vref is the same voltage VrefO in the present invention and the conventional example in the standard state, and the description is easy to understand. That is, conventional example: 200 μA Invention: (Vcc0-VrefO) / R1 + I1 = (5V-
2.3 V) /19.1 kΩ + 59 μA = 200 μA FIG. 4 shows the results of simulating the operations of the reference voltage generating circuit 17 of the present invention and the conventional reference voltage generating circuit 23. In this example, the power supply voltage Vcc is 4.5V to 5.5V
Is changing. In the conventional example, the reference voltage Vref is a fixed value even if the power supply voltage changes, but in the case of the present invention, it can be seen that the reference voltage Vref is a value that changes according to the change in the power supply voltage.

In the current generating circuit 18, the reference current 2 × I0 generated by the constant current source I4 is supplied to the transistor Q4.
Current mirror circuit CM1 composed of a transistor and a transistor Q6
Will be folded back. Therefore, the collector current of the transistor Q6 is 2 × I0, which is the same as the reference current, and this value is always constant. In this example, the collector current is 200
μA. The differential amplifier DFA converts the difference voltage between the base (V-: reference voltage Vref) of the transistor Q5 and the base (V +: control voltage Vpll) of the transistor Q8 into a current and outputs it as a collector current of the transistor Q8.
The collector current Ic8 of the transistor Q8 is expressed by the following equation.

Ic8 = I0 + (Vpll-Vref) / (R2 + R3) (4) The emitter equivalent resistances of the transistors Q5 and Q6 are ignored in the above equation. Two current mirror circuits CM2 and C
Ideally, the current transfer circuit 19 composed of M3 desirably has a one-to-one relationship between the input current and the output current. However, since the transistor generally has an Early effect, when the power supply voltage changes and the collector-emitter voltage Vce of the transistor changes, the collector current Ic is changed.
Has the property of changing. When the early voltage of the transistor is Va for both NPN type and PNP type, the relation between the collector current Ic1 when the collector-emitter voltage Vce is Vce1 and the collector current Ic2 when the collector-emitter voltage Vce is Vce2 Is expressed as Ic2 / Ic1 = (Vce2 + Va) / (Vce1 + Va) (5). The fluctuation amount from the fluctuation ΔVcc of the power supply voltage Vcc is: Vce2 = Vce1 + ΔVcc ΔIc = Ic2-Ic1 = (Vce2 + Va) / (Vce1 + Va) × Ic1-Ic1 = (Vce2-Vce1) / (Vce1 + Va) × Ic1ΔC1 Va × Ic1 (Va is sufficiently larger than Vce1) (6) Therefore, the collector current Ic9 of the transistor Q9 is
When the power supply voltage Vcc fluctuates according to the fluctuation of the power supply voltage Vcc and the current value when the power supply voltage Vcc is the standard value is Ic90, the collector current Ic9
Ic9 = Ic90 + (Vcc-Vcc0) / Va * Ic90 = Ic90 * (1+ (Vcc-Vcc0) / Va) (7) Similarly, the collector current I of the transistors Q11 and Q12 is
c11 and Ic12 are as follows: Ic11 = Ic12 = Ic110 + (Vcc-Vcc0) / Va * Ic110 = Ic110 * (1+ (Vcc-Vcc0) / Va) (8) This current becomes the input current of the oscillation circuit 11. Let this input current be the control current Iosc. When Vcc = Vcc0, assuming that the input / output current ratio of the current mirror circuit is 1: 1, Ic90 = Ic8 and Ic110 = Ic9. Therefore, when these are combined, the control current Iosc of the oscillation circuit 11 becomes Iosc = Ic11. = Ic110 * (1+ (Vcc-Vcc0) / Va) = Ic9 * (1+ (Vcc-Vcc0) / Va) = Ic9 * (1+ (Vcc-Vcc0) / Va) * (1+ (Vcc-Vcc0) / Va) = Ic8 * (1+ (Vcc-Vcc0) / Va) * (1+ (Vcc-Vcc0) / Va) Since Vcc-Vcc0 is minute, the second term of Vcc-Vcc0 can be omitted, and Ic8 * (1 + 2 * (Vcc) -Vcc0) / Va) = (I0 + (Vpll-Vref) / (R2 + R3)) * (1 + 2 * (Vcc-Vcc0) / Va) (9).

In FIG. 5, Vcc = Vcc0 and control voltage Vpll
It shows a change in the control current Iosc of the oscillation circuit when is changed. When the power supply voltage does not change, the conventional method and the present invention are exactly the same.

FIG. 6 shows I when the power supply voltage Vcc is changed.
It shows the change in osc. In this case, it can be seen that the control current Iosc changes in the conventional circuit, but the circuit of the present invention is stable.

The oscillation frequency of the oscillation circuit 11 changes in proportion to the control current Iosc. That is, the capacitor C
A control current Iosc is supplied to both ends of 1, and the control current Iosc
The capacitor C1 is charged and discharged according to osc to perform an oscillating operation, and a square output signal VC1 is output. The oscillation frequency F of the oscillator circuit 11 is
When the forward voltage of Q17 is Vosc, it is expressed by the following equation.

F = Iosc / (4 × Vosc × C1) (10) The above equation does not include the power supply voltage Vcc. For this reason,
This relation does not depend on the power supply voltage. In this example,
Iosc = 100 μA, Vosc = 0.7V, C1 = 10p
F and F = 3.5 MHz.

7 and 8 show output waveforms of the oscillator circuit 11. In FIG. 7, since Vcc = Vcc0, there is no difference in oscillation frequency between the conventional example and the present invention. On the other hand, FIG.
Shows the case where the power supply voltage Vcc is increased from 5V to 5.5V. In this case, it can be seen that the oscillation frequency is narrowed and the frequency is increased in the conventional circuit, but the frequency is stable in the circuit of the present invention.

FIG. 9 shows waveforms at both ends of the capacitor C1. Here, when the formula of the oscillation frequency is derived, F = 1 / (4 * Vosc * C1) * (I0 + (Vpll-Vref) / (R2 + R3)) * (1 + 2 * (Vcc-Vcc0) / Va) ... ( 11) becomes. To simplify the formula, if 1 / (4 × Vosc × C1) = A 1 / (R2 + R3) = l 2 / Va = k, then F = A × (I 0 + l × (Vpll −Vref)) × ( 1 + k * (Vcc-Vcc0)) (12). In the case of the present invention, it is Vcc and Vref that depend on the power supply voltage Vcc in this equation, and Vref = Vref0 + mx
When (Vcc-Vcc0) is given, F = A * (I0 + l * (Vpll- (Vref0 + m * (Vcc-Vcc0)))) * (1 + k * (Vcc-Vcc0)) (13) When differentiated, dF / dVcc = A * ((-l * m) * (1 + k * (Vcc-Vcc0)) + (I0 + l * (Vpll- (Vref0 + m * (Vcc-Vcc0)))) * k) ... 14) Among the minute changes, Vcc and Vcc0 and Vpll and Vref0 are equal, so the above equation is: dF / dVcc = A * ((-l * m) + (I0 + l * (Vpll-Vref0)) * k ) = A * (-l * m + k * I0) (15)

An object of the present invention is to minimize the fluctuation of the oscillation frequency F, in other words, to optimally set the coefficient m in the above equation. Therefore, the optimum value of m is obtained by setting the differential coefficient of the power source voltage Vcc of the frequency F to zero.

When A × (−l × m + k × I0) = 0 (16) is solved for m, A is not zero, so that m = k × I0 / l. When the above equation is restored, m = 2 × I0 × (R2 + R3) / Va (17) The coefficient m of the reference voltage generating circuit 17 is set so as to satisfy this condition. In this example, I0 = 10
If 0 μA, R2 = R3 = 5 kΩ, and Va = 100 V, then m = 0.02.

On the other hand, from the configuration of the reference voltage generating circuit 17 and the above equations (2) and (13), m = 3 × Re / (R1 + 3 × Re) (18) Therefore, R1 = (1 / m-1 ) × 3 × Re (19) Substituting the above numerical values into this gives R1 = 19.1 kΩ, which is the optimum value of the resistance R1.

In the case of the conventional example shown in FIG. 4, the reference voltage Vref
Is independent of the power source voltage Vcc, the oscillation frequency F is F = A * (I0 + l * (Vpll-Vref)) * (1 + k * (Vcc-Vcc0)) (20). Therefore, the value obtained by differentiating this with the power supply voltage Vcc is dF / dVcc = A * (I0 + l * (Vpll-Vref)) * k) (21), and Vpll and Vref are respectively small changes. Since they are equal, dF / dVcc = A.times.k.times.I0 = 2 / (4.times.Vosc.times.C1.times.Va) .times.I0 (22). Therefore, since the differential coefficient of the power supply voltage Vcc of the frequency F cannot be zero, the oscillation frequency fluctuates due to the fluctuation of the power supply voltage. 10 and 11 show simulation results when a 50 Hz signal, which is an example of the frequency of the commercial AC voltage, is superimposed on the power supply voltage. FIG. 10 shows the power supply voltage used for the simulation. As shown, this voltage is a sine wave that fluctuates ± 100 mV around 5V. FIG. 11 shows the result of the simulation. As shown in the figure, in the case of the present invention, the variation amount of the control voltage Iosc of the oscillation circuit 11 is significantly smaller than that in the conventional case.

According to the above-described embodiment, the reference voltage generating circuit 17 generates the reference voltage which depends on the fluctuation of the power supply voltage and cancels the Early effect of the bipolar transistor which constitutes the current generating circuit and the like. Therefore, even if the power supply voltage changes due to noise, the oscillation frequency can be stably maintained.

[0033] because it can constitute a strong oscillation circuit to the power supply voltage of the noise, the power supply circuit (not shown) for supplying power to the oscillation circuit, there is no problem even include some ripple in its output voltage. Therefore, there is an advantage that the configuration of the power supply circuit can be simplified.

FIG. 12 shows a bipolar linear integrated circuit to which the present invention is applied. For example, a UH for a video tape recorder adopting a frequency synthesizer system.
The F band high frequency modulation circuit is shown. In this high frequency modulation circuit, the same parts as those in FIG. 2 are designated by the same reference numerals. In the same figure, a portion related to the present invention will be described. The reference voltage generation circuit 17, the current generation circuit 18, the current transmission circuit 19, and the oscillation circuit 11 of the present invention are applied to a voice VCO (voltage controlled oscillator) 30. The voice VCO 30 takes in a PAL or NTSC voice input signal (voltage level) supplied from the voice input end (3) between the output end of the current generation circuit 18 and the input end of the current transfer circuit 19 and oscillates. The output signal of the audio VCO 30 is supplied to the counter 12 and is also supplied to the frequency converter 32 including a frequency modulator via the selection switch 31 for RF.
It is modulated by a carrier signal supplied from a carrier OSC (high frequency carrier oscillator circuit) 33.

On the other hand, the video signal supplied from the video signal input terminal (2) is supplied to the video modulator 38 via the clamp circuit 35, the white clip circuit 36 and the selection switch 37. The video signal supplied to the video modulator 38 is modulated by the carrier signal supplied from the RF carrier OSC33. The video signal output from the video modulator 38 is mixed with the audio signal from the frequency converter 32 by the mixer 39 and output from the RF output terminal (11) via the buffer amplifier 40.

Reference numeral 41 is a test pattern generation circuit (TS
G), 42 is a video signal system PLL circuit, 43 is a reference signal oscillator made of a crystal oscillator, and 44 is an input terminal (5).
In (7), for example, a mode switching circuit (I ² C BUS) for switching the mode in response to a command supplied from a microcomputer (not shown), and 45 modulates the SECAM audio signal supplied from the input terminal (4). AM modulator, 46 is a buffer circuit.

As described above, when the circuit of the present invention is applied to the high frequency modulation circuit, the oscillation frequency does not fluctuate even when the power supply voltage fluctuates, so that the frequency converter 32 has an advantage that noise generation can be reduced. is doing.

The reason why the oscillation frequency fluctuates due to the fluctuation of the power supply voltage is not limited to the Early effect of the transistor, and even if the characteristic fluctuation of other general circuit elements causes the same correction as in the present invention. It is possible to

Further, the configuration of the oscillation circuit 11 is not limited to the multivibrator, and any other circuit that controls the oscillation frequency by changing the current may be used. Moreover, in the above-described embodiment, the oscillation circuit 11 does not have a circuit that depends on the power supply voltage, but even in the case of a circuit configuration in which the oscillation frequency changes depending on the power supply voltage, the variation coefficient changes in the current transfer unit. The oscillation frequency can be stabilized by adding and correcting the minutes.

Further, in the current generation circuit 18, even when the reference current varies according to the power supply voltage, the reference voltage Vref generated in the reference voltage generation circuit 17 varies according to the power supply voltage. Fluctuations can be offset.

Further, the configuration of the reference voltage generating circuit 17 is as follows.
The configuration is not limited to the configuration shown in FIG. 1 as long as the reference voltage can be generated according to the fluctuation of the power supply voltage.
Of course, various modifications can be made without departing from the spirit of the invention.

[0042]

As described above in detail, according to the present invention, it is possible to provide a PLL oscillation circuit capable of preventing the oscillation frequency from changing even when the power supply voltage changes.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a PLL oscillator circuit to which the present invention is applied.

FIG. 3 is a circuit diagram showing a conventional reference voltage generating circuit.

FIG. 4 is a diagram showing the results of simulating the operations of the reference voltage generation circuit of the present invention and the conventional reference voltage generation circuit.

FIG. 5 is a diagram showing changes in the control current Iosc of the oscillation circuit when the control voltage Vpll is changed when the power supply voltage is constant.

FIG. 6 is a control current Ios when the power supply voltage is changed.
The figure which shows the change of c.

FIG. 7 is a diagram showing an output waveform of the oscillation circuit when the power supply voltage is constant.

FIG. 8 is a diagram showing an output waveform of the oscillation circuit when the power supply voltage is changed.

FIG. 9 is a diagram showing waveforms at both ends of a capacitor C1.

FIG. 10 is a diagram showing a power supply voltage used for simulation.

FIG. 11 is a diagram showing a simulation result regarding fluctuations in oscillation frequency due to fluctuations in power supply voltage.

FIG. 12 is a configuration diagram showing an example of a high frequency modulation circuit to which the present invention is applied.

[Explanation of symbols]

11 ... Oscillation circuit, 12 ... Counter, 13 ... Phase comparison circuit, 14 ... Charge pump circuit, 15 ... PLL circuit, 16 ... loop filter, 17 ... Reference voltage generating circuit, 18 ... current generation circuit, 19 ... Current transfer circuit, I1 ... constant current source, Q1, Q2, Q3 ... Diodes, R1 ... resistance.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H03L ⁷ /06-7/14 H03B 5/00-5/28

Claims (4)

(57) [Claims] 1. An oscillating circuit composed of a bipolar transistor whose oscillating frequency changes according to a change of an input current, a voltage generating circuit for generating a control voltage according to an oscillating frequency of the oscillating circuit, and a fluctuation of a power supply voltage. A reference voltage generating circuit that generates a reference voltage that changes according to the reference voltage, and a bipolar transistor that generates a control current by comparing a control voltage output from the voltage generating circuit with a reference voltage generated by the reference voltage generating circuit. And a current transmitting circuit configured to transmit the current output from the current generating circuit to the voltage controlled oscillator circuit. 2. An oscillation circuit composed of a bipolar transistor whose oscillation frequency changes according to a change in input current, a counter for dividing an output signal of the oscillation circuit, a phase of the output signal of the counter and a reference signal. A phase comparison circuit that compares the output signal of the phase comparison circuit, a loop filter that includes a low-pass filter that generates a control voltage from the output signal of the charge pump circuit, and a power supply A reference voltage generating circuit that generates a reference voltage that changes according to a change in voltage, a control voltage that is output from the loop filter, and a reference voltage that is generated by the reference voltage generating circuit are compared to generate a control current. A current generation circuit composed of a bipolar transistor, and a current output from the current generation circuit are supplied to the oscillation circuit. P, characterized by comprising a current transfer circuit for transferring to
LL type oscillator circuit. 3. The reference voltage generating circuit includes a constant current source connected in series between a power source and ground, an impedance circuit that generates a voltage according to a flowing current, and a resistor connected in parallel to the constant current source. The PLL type oscillation circuit according to claim 1, further comprising: 4. The reference voltage generating circuit is the bipolar device.
Generates a reference voltage that cancels the Early effect of the transistor
The PLL type generator according to claim 1 or 2, characterized in that
Swing circuit.