CN102868366A - High-frequency voltage-controlled oscillator - Google Patents
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Abstract
The invention provides a high-frequency voltage-controlled oscillator, comprising: the circuit comprises a resonant circuit, a negative resistance circuit, a current source circuit and a buffer circuit; the current source circuit is used for generating current for the voltage-controlled oscillator to work; the resonance circuit is used for generating an oscillation signal; the negative resistance circuit generates a negative resistance to counteract a positive resistance generated by the resonant circuit; the buffer circuit is used for buffering the oscillation signal generated by the resonance circuit and then outputting the buffered oscillation signal so as to isolate the buffered oscillation signal from an external signal. The oscillation signal generated by the resonant circuit in the high-frequency voltage-controlled oscillator provided by the invention is output after being buffered by the buffer circuit, so that the interference of an external signal to the oscillation circuit can be avoided, and the noise is reduced. And the current source circuit adopts a heterojunction bipolar transistor, and the heterojunction bipolar transistor has lower flicker noise, so that the phase noise performance of the whole voltage-controlled oscillator can be improved. Meanwhile, the MOS capacitive reactance tube is adopted in the resonant circuit, so that the voltage-controlled oscillator has higher oscillation frequency and larger tuning range.
Description
Technical Field
The invention relates to the technical field of integrated circuits, in particular to a high-frequency voltage-controlled oscillator.
Background
A voltage-controlled oscillator (VCO) refers to an oscillating circuit in which an output frequency corresponds to an input control voltage.
The voltage-controlled oscillator is one of the most important basic circuits in an integrated circuit, and the circuit implementation modes of the voltage-controlled oscillator are mainly two, namely a Ring voltage-controlled oscillator (Ring VCO) and an inductor-capacitor voltage-controlled oscillator (LCVCO). Voltage controlled oscillators are widely used in clock synchronization (ClockSynchronization) circuits in microprocessors; a frequency synthesizer (frequency synthesizer) in a wireless communication transceiver; clock Recovery Circuit (CRC) and Multi-phase Sampling (Multi-phase Sampling) circuits in fiber optic communications.
The oscillation frequency is one of the main parameters for the performance of a balanced voltage controlled oscillator. In most cases, the oscillation frequency of the voltage-controlled oscillator is determined by the inductance and capacitance in the resonant circuit, but the parasitic capacitance of the voltage-controlled oscillator, particularly the parasitic capacitance connected to the resonant circuit, is also a major factor affecting the voltage-controlled oscillator to obtain a higher oscillation frequency.
Referring to fig. 1, a schematic diagram of a prior art voltage controlled oscillator is shown.
The resonant circuit of the voltage controlled oscillator shown in fig. 1 includes: the circuit comprises a differential inductor L0, a first variable capacitor C1, a second variable capacitor C23, a third capacitor C3, a fourth capacitor C4, a first resistor R1 and a second resistor R2;
one end of the differential inductor L0 is connected with the negative output end of the voltage-controlled oscillator, and the other end of the differential inductor L0 is connected with the positive output end of the voltage-controlled oscillator;
one end of the first variable capacitor C1 is connected to a first node a, and the other end is connected to a first control voltage ATUNE;
one end of the second variable capacitor C2 is connected to a second node B, and the other end is connected to the first control voltage ATUNE;
one end of the first resistor R1 is connected with the first node A, and the other end is grounded;
one end of the second resistor R2 is connected with the second node B, and the other end is grounded;
two ends of the third capacitor C3 are respectively connected to the first node a and the negative output end of the voltage-controlled oscillator, and two ends of the fourth capacitor C4 are respectively connected to the second node B and the positive output end of the voltage-controlled oscillator.
As can be seen from the above analysis, the oscillation signal generated by the resonant circuit in the voltage-controlled oscillator in the prior art is directly output without any isolation from the external signal, so that the external signal is liable to interfere with the oscillation circuit, thereby increasing the noise of the voltage-controlled oscillator.
Disclosure of Invention
The invention aims to provide a high-frequency voltage-controlled oscillator, which can improve the noise performance of the high-frequency voltage-controlled oscillator.
The invention provides a high-frequency voltage-controlled oscillator, comprising: the circuit comprises a resonant circuit, a negative resistance circuit, a current source circuit and a buffer circuit;
the resonant circuit is used for generating an oscillation signal of the voltage-controlled oscillator, and is an inductance-capacitance resonant circuit, wherein a capacitor adopts an MOS capacitive reactance tube;
the negative resistance circuit is used for generating negative resistance so as to counteract positive resistance generated by the resonance circuit;
the current source circuit is used for generating a current for the voltage-controlled oscillator to work; the current source circuit comprises a seventh heterojunction bipolar transistor; an emitter electrode of the seventh heterojunction bipolar transistor is grounded, and a collector electrode of the seventh heterojunction bipolar transistor is connected with a negative resistance circuit; the base electrode of the seventh heterojunction bipolar transistor is connected with a third control voltage;
and the buffer circuit is used for buffering the oscillation signal generated by the resonance circuit and then outputting the buffered oscillation signal so as to isolate the buffered oscillation signal from an external signal.
Preferably, the resonance circuit includes: the circuit comprises a differential inductor, a first MOS capacitive reactance tube, a second MOS capacitive reactance tube, a third capacitor, a fourth capacitor, a first resistor and a second resistor;
one end of the differential inductor is connected with the third node, and the other end of the differential inductor is connected with the fourth node; a tap of the differential inductor is connected with a power supply;
the drain electrode and the source electrode of the first MOS capacitive reactance tube are both connected with a first control voltage, and the drain electrode and the source electrode of the second MOS capacitive reactance tube are both connected with the first control voltage;
the grid electrode of the first MOS capacitive reactance tube is connected with a first node, and the grid electrode of the second MOS capacitive reactance tube is connected with a second node;
two ends of the first resistor are respectively connected with the first node and the ground; two ends of the second resistor are respectively connected with the second node and the ground;
two ends of the third capacitor are respectively connected with the first node and the third node, and two ends of the fourth capacitor are respectively connected with the second node and the fourth node;
the third node is a first phase connection point of the resonance circuit and the buffer circuit and outputs a first resonance signal; the fourth node is a second connection point of the resonant circuit and the buffer circuit, and outputs a second resonant signal.
Preferably, the buffer circuit includes: the third bipolar transistor, the fourth bipolar transistor, the fifth bipolar transistor, the sixth bipolar transistor, the seventh capacitor, the eighth capacitor, the fifth resistor and the sixth resistor;
the base electrode of the third bipolar transistor is connected with a third node, the collector electrode of the third bipolar transistor is connected with the power supply, and the emitter electrode of the third bipolar transistor is connected with a fifth node;
the base electrode of the fourth bipolar transistor is connected with a fourth node, the collector electrode of the fourth bipolar transistor is connected with the power supply, and the emitter electrode of the fourth bipolar transistor is connected with a sixth node;
one end of the seventh capacitor is connected with the fifth node, and the other end of the seventh capacitor is connected with the base electrode of the fifth bipolar transistor;
a collector of the fifth bipolar transistor is connected with the power supply, and an emitter of the fifth bipolar transistor is grounded through the fifth resistor;
one end of the eighth capacitor is connected with the sixth node, and the other end of the eighth capacitor is connected with the base electrode of the sixth bipolar transistor;
a collector of the sixth bipolar transistor is connected with the power supply, and an emitter of the sixth bipolar transistor is grounded through the sixth resistor;
an emitter electrode of the fifth bipolar transistor is a first output end of the voltage-controlled oscillator, and an emitter electrode of the sixth bipolar transistor is a second output end of the voltage-controlled oscillator; wherein,
the third node is a first phase connection point of the resonance circuit and the buffer circuit; the fourth node is a second connection point of the resonance circuit and the buffer circuit;
the fifth node is a first phase connection point of the buffer circuit and the negative resistance circuit; and the sixth node is a second connection point of the buffer circuit and the negative resistance circuit.
Preferably, the negative resistance circuit includes: the first bipolar transistor, the second bipolar transistor, the fifth capacitor, the sixth capacitor, the third resistor, the fourth resistor and the ninth capacitor;
the collector of the first bipolar transistor is connected with a fifth node, the emitter of the first bipolar transistor is connected with the current source circuit, and the base of the first bipolar transistor is connected with a second control voltage through the third resistor;
the collector of the second bipolar transistor is connected with a sixth node, the emitter of the second bipolar transistor is connected with the current source, and the base of the second bipolar transistor is connected with the second control voltage through the fourth resistor;
two ends of the ninth capacitor are respectively connected with the second control voltage and the ground;
one end of the fifth capacitor is connected with the fifth node, and the other end of the fifth capacitor is connected with the base electrode of the second bipolar transistor;
one end of the sixth capacitor is connected with the sixth node, and the other end of the sixth capacitor is connected with the base electrode of the first bipolar transistor; wherein,
the fifth node is a first phase connection point of the buffer circuit and the negative resistance circuit; the sixth node is a second connection point of the buffer circuit and the negative resistance circuit;
the emitter of the first bipolar transistor is a first end of the negative resistance circuit, and the emitter of the second bipolar transistor is a second end of the negative resistance circuit.
Preferably, the first and second MOS capacitive reactance tubes work in an accumulation region or a depletion region.
Preferably, the capacitance values of the third capacitor and the fourth capacitor are at least ten times larger than the capacitance values of the first MOS capacitive reactance tube and the second MOS capacitive reactance tube.
Preferably, the first and second bipolar transistors operate in a forward operating region.
Preferably, the seventh heterojunction bipolar transistor operates in a forward operating region.
Preferably, the third bipolar transistor, the fourth bipolar transistor, the fifth bipolar transistor and the sixth bipolar transistor operate in the forward operating region.
Preferably, the buffer circuit includes: the third MOS tube, the fourth MOS tube, the fifth MOS tube, the sixth MOS tube, the seventh capacitor, the eighth capacitor, the fifth resistor and the sixth resistor;
the grid electrode of the third MOS tube is connected with a third node, the drain electrode of the third MOS tube is connected with the power supply, and the source electrode of the third MOS tube is connected with a fifth node;
the grid electrode of the fourth MOS tube is connected with a fourth node, the drain electrode of the fourth MOS tube is connected with the power supply, and the source electrode of the fourth MOS tube is connected with a sixth node;
one end of the seventh capacitor is connected with the fifth node, and the other end of the seventh capacitor is connected with the base electrode of the fifth bipolar transistor;
the drain electrode of the fifth MOS tube is connected with the power supply, and the source electrode of the fifth MOS tube is grounded through the fifth resistor;
one end of the eighth capacitor is connected with the sixth node, and the other end of the eighth capacitor is connected with the base electrode of the sixth MOS tube;
the drain electrode of the sixth MOS tube is connected with the power supply, and the source electrode of the sixth MOS tube is grounded through the sixth resistor;
the source electrode of the fifth MOS transistor is a first output end of the voltage-controlled oscillator, and the source electrode of the sixth MOS transistor is a second output end of the voltage-controlled oscillator; wherein,
the third node is a first phase connection point of the resonance circuit and the buffer circuit; the fourth node is a second connection point of the resonance circuit and the buffer circuit;
the fifth node is a first phase connection point of the buffer circuit and the negative resistance circuit; and the sixth node is a second connection point of the buffer circuit and the negative resistance circuit.
Compared with the prior art, the invention has the following advantages:
in the high-frequency voltage-controlled oscillator provided by the invention, the current source circuit is used for generating the working current of the voltage-controlled oscillator; the resonance circuit is used for generating an oscillation signal; the negative resistance circuit generates a negative resistance to counteract a positive resistance generated by the resonant circuit; the buffer circuit is used for buffering the oscillation signal generated by the resonance circuit and then outputting the buffered oscillation signal so as to isolate the buffered oscillation signal from an external signal. The oscillation signal generated by the resonant circuit in the high-frequency voltage-controlled oscillator provided by the invention is output after being buffered by the buffer circuit, so that the interference of an external signal to the oscillation circuit can be avoided, and the noise is reduced. And the current source circuit adopts a heterojunction bipolar transistor, and the heterojunction bipolar transistor has lower flicker noise, so that the phase noise performance of the whole voltage-controlled oscillator can be improved. Meanwhile, the MOS capacitive reactance tube is adopted in the resonant circuit, so that the voltage-controlled oscillator has higher oscillation frequency and larger tuning range.
Drawings
Fig. 1 is a schematic diagram of a prior art voltage controlled oscillator;
FIG. 2 is a schematic diagram of an embodiment of a high frequency voltage controlled oscillator provided by the present invention;
FIG. 3 is a second circuit diagram of an embodiment of a high frequency voltage controlled oscillator provided by the present invention;
fig. 4 is a circuit diagram of a high-frequency voltage-controlled oscillator according to an embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
Referring to fig. 2, a schematic diagram of an embodiment of a high frequency voltage controlled oscillator according to the invention is provided.
The invention provides a high-frequency voltage-controlled oscillator, comprising: the resonant circuit 100, the negative resistance circuit 200, the current source circuit 300 and the buffer circuit 400;
the resonant circuit 100 is configured to generate an oscillation signal of a voltage-controlled oscillator, and the resonant circuit 100 is an inductance-capacitance resonant circuit, where a capacitor adopts a MOS capacitance reactance tube;
the negative resistance circuit 200 is used for generating a negative resistance to counteract the positive resistance generated by the resonant circuit 100;
the current source circuit 300 is used for generating a current for operating the voltage-controlled oscillator; the current source circuit 300 includes a seventh Heterojunction Bipolar Transistor (HBT); an emitter electrode of the seventh heterojunction bipolar transistor is grounded, and a collector electrode of the seventh heterojunction bipolar transistor is connected with the first end and the second end of the negative resistance circuit; the base electrode of the seventh heterojunction bipolar transistor is connected with a third control voltage;
the buffer circuit 400 is configured to buffer the oscillation signal generated by the resonant circuit 100 and then output the buffered oscillation signal to be isolated from an external signal.
In the high frequency voltage-controlled oscillator provided by the invention, the current source circuit 300 is used for generating the working current of the voltage-controlled oscillator; the resonant circuit 100 is used for generating an oscillating signal; the negative resistance circuit 200 generates a negative resistance to cancel the positive resistance generated by the resonant circuit 100; the buffer circuit 400 is configured to buffer the oscillation signal generated by the resonant circuit and then output the buffered oscillation signal to be isolated from the external signal. The oscillation signal generated by the resonant circuit 100 in the high-frequency voltage-controlled oscillator provided by the invention is buffered by the buffer circuit 400 and then output, so that the interference of an external signal to the oscillation circuit can be avoided. And the current source circuit 300 employs a heterojunction bipolar transistor, which has low flicker noise, so that the phase noise of the whole voltage-controlled oscillator can be improved. Meanwhile, the MOS capacitive reactance tube is adopted in the resonant circuit, so that the voltage-controlled oscillator has higher oscillation frequency and larger tuning range.
In order to make the technical solutions of the present invention better understood and implemented by those skilled in the art, specific implementations of the high-frequency voltage-controlled oscillator provided by the present invention are described in detail below with reference to the accompanying drawings.
Referring to fig. 3, it is a circuit diagram of an embodiment of a high frequency voltage controlled oscillator according to the present invention.
The base of Q7 is connected to the third control voltage VBIAS.
By adjusting the magnitude of the third control voltage VBIAS, the seventh heterojunction bipolar transistor Q7 is ensured to operate in the forward operating region.
Flicker noise of the current source circuit, which is generated by traps in the active device randomly trapping and releasing carriers, is one of the factors affecting the phase noise performance of the voltage controlled oscillator. The HBT does not belong to a surface device, has fewer traps and generates less flicker noise, so that the phase noise performance of the voltage-controlled oscillator can be improved.
The resonance circuit includes: the circuit comprises a differential inductor L0, a first MOS capacitive reactance tube C1, a second MOS capacitive reactance tube C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1 and a second resistor R2;
one end of the differential inductor L0 is connected with a third node C, and the other end of the differential inductor L0 is connected with a fourth node D; a tap of the differential inductor L0 is connected with a power supply;
the drain and the source of the first MOS capacitive reactance tube C1 are both connected with a first control voltage ATUNE, and the drain and the source of the second MOS capacitive reactance tube C2 are both connected with the first control voltage ATUNE;
the grid electrode of the first MOS capacitive reactance tube C1 is connected with a first node A, and the grid electrode of the second MOS capacitive reactance tube C2 is connected with a second node B;
the first MOS capacitor C1 and the second MOS capacitor C2 work in an accumulation region and a depletion region.
The capacitance values of the third capacitor C3 and the fourth capacitor C4 are at least ten times larger than the capacitance values of the first MOS capacitive reactance tube C1 and the second MOS capacitive reactance tube C2. This ensures that the voltage controlled oscillator has a wide frequency tuning range.
The operating frequency of the voltage-controlled oscillator can be adjusted by adjusting the magnitude of the first control voltage ATUNE.
Two ends of the first resistor R1 are respectively connected with the first node A and the ground; two ends of the second resistor R2 are respectively connected with the second node B and the ground;
two ends of the third capacitor C3 are connected to the first node a and the third node C, respectively, and two ends of the fourth capacitor C4 are connected to the second node B and the fourth node D, respectively;
the third node C is a first phase connection point of the resonance circuit and the buffer circuit and outputs a first resonance signal; the fourth node D is a second connection point of the resonance circuit and the buffer circuit, and outputs a second resonance signal.
The buffer circuit includes: a third bipolar transistor Q3, a fourth bipolar transistor Q4, a fifth bipolar transistor Q5, a sixth bipolar transistor Q6, a seventh capacitor C7, an eighth capacitor C8, a fifth resistor R5, and a sixth resistor R6;
the base electrode of the third bipolar transistor Q3 is connected with the third node C, the collector electrode of the third bipolar transistor Q3 is connected with the power supply, and the emitter electrode of the third bipolar transistor Q3 is connected with the fifth node M;
the base of the fourth bipolar transistor Q4 is connected with the fourth node D, the collector is connected with the power supply, and the emitter is connected with the sixth node N;
one end of the seventh capacitor C7 is connected to the fifth node M, and the other end is connected to the base of the fifth bipolar transistor Q5;
the collector of the fifth bipolar transistor Q5 is connected with the power supply, and the emitter is grounded through the fifth resistor R5;
one end of the eighth capacitor C8 is connected to the sixth node N, and the other end is connected to the base of the sixth bipolar transistor Q6;
the collector of the sixth bipolar transistor Q6 is connected with the power supply, and the emitter is grounded through the sixth resistor R6;
an emitter of the fifth bipolar transistor Q5 is a first output terminal NOUT of the voltage-controlled oscillator, and an emitter of the sixth bipolar transistor Q6 is a second output terminal POUT of the voltage-controlled oscillator;
the third node C is a first phase connection point of the resonance circuit and the buffer circuit; the fourth node D is a second connection point of the resonance circuit and the snubber circuit;
the fifth node M is a first phase connection point of the buffer circuit and the negative resistance circuit; and the sixth node N is a second connection point of the buffer circuit and the negative resistance circuit.
The functions of the C7 and the C8 are to isolate the direct current signal and enable the alternating current signal to pass through.
The buffer circuit buffers the oscillation signal output by the resonance circuit and then outputs the buffered oscillation signal, so that the working frequency of the voltage-controlled oscillator is not influenced by an external signal.
Wherein Q5 and R5 form a follower, and Q6 and R6 form a follower.
The third bipolar transistor Q3, the fourth bipolar transistor Q4, the fifth bipolar transistor Q5, and the sixth bipolar transistor Q6 operate in the forward operating region.
In the high frequency voltage controlled oscillator provided by the present invention, the negative resistance circuit includes: a first bipolar transistor Q1, a second bipolar transistor Q2, a third resistor R3, a fourth resistor R4, a ninth capacitor C9, a fifth capacitor C5, and a sixth capacitor C6;
a collector of the first bipolar transistor Q1 is connected to the fifth node M, an emitter thereof is connected to the current source circuit, and a base thereof is connected to a second control voltage CDC through the third resistor R3;
a collector of the second bipolar transistor Q2 is connected to the sixth node N, an emitter thereof is connected to the current source, and a base thereof is connected to the second control voltage CDC through the fourth resistor R4;
both ends of the ninth capacitor C9 are connected to the second control voltage CDC and ground, respectively.
One end of the fifth capacitor C5 is connected to the fifth node M, and the other end is connected to the base of the second bipolar transistor Q2;
one end of the sixth capacitor C6 is connected to the sixth node N, and the other end is connected to the base of the first bipolar transistor Q1.
The emitter of the first bipolar transistor Q1 is a first terminal of a negative resistance circuit, and the emitter of the second bipolar transistor Q2 is a second terminal of the negative resistance circuit.
By adjusting the magnitude of the second control voltage CDC, Q1 and Q2 are guaranteed to be in the forward operating region.
In the high-frequency voltage-controlled oscillator according to the present invention, the first bipolar transistor Q1 and the second bipolar transistor Q2 may be heterojunction bipolar transistors.
The capacitance values of the fifth capacitor C5 and the sixth capacitor C6 are one tenth of the capacitance values of the first MOS capacitive reactance tube C1 and the second MOS capacitive reactance tube C2. This ensures a wide frequency tuning range of the voltage controlled oscillator.
The oscillation frequency of the voltage controlled oscillator may be expressed as:
wherein L is the inductance of the differential inductor L0; cpEquivalent parallel capacitance of the resonance circuit. The equivalent parallel capacitance of the voltage-controlled oscillator shown in fig. 1 of the prior art includes not only the capacitances (C1, C2, C3, C4), but also the fifth capacitance C5 and the sixth capacitance C6 connected to the resonant circuit, and the base capacitances of the first transistor Q1 and the second transistor Q2. In summary, the voltage-controlled oscillator shown in fig. 1 has a larger equivalent parallel capacitance of the resonant circuit, since the oscillation frequency is inversely proportional to the equivalent parallel capacitance. Therefore, the voltage-controlled oscillator has a low oscillation frequency.
However, in the high-frequency voltage-controlled oscillator provided by the present invention, the capacitors directly and indirectly connected to the differential inductor L0 in the resonant circuit include a third capacitor C3, a fourth capacitor C4, a capacitor of the first MOS capacitive reactance transistor C1, a capacitor of the second MOS capacitive reactance transistor C2, and equivalent capacitors of the bases of the third bipolar transistor Q3 and the fourth bipolar transistor Q4; thus, compared with the voltage-controlled oscillator in the prior art, the equivalent parallel capacitance of the resonant circuit is reduced, and the oscillation frequency is inversely proportional to the equivalent parallel capacitance as can be seen from formula (1). Therefore, the high frequency voltage controlled oscillator has a high oscillation frequency. And the current source adopts a heterojunction bipolar transistor, and the heterojunction bipolar transistor has lower flicker noise, so that the phase noise of the whole voltage-controlled oscillator can be improved.
It should be noted that the oscillation starting condition of the voltage-controlled oscillator can be expressed as:
gmRp≥2（2）
wherein, gmIs the equivalent transconductance of a negative resistance circuit connected in parallel with the resonant circuit; rpIs an equivalent resistance in parallel with the resonant circuit. Because the HBT has larger transconductance under the same power consumption condition, the negative resistance circuit in the voltage-controlled oscillator adopts the HBT (Q1, Q2) to enable the voltage-controlled oscillator to start oscillating quickly.
In the resonant circuit, MOS capacitive reactance tubes (C1, C2) are used. The control MOS capacitance reactance tube works in an accumulation region or a depletion region, and the capacitance value of the control MOS capacitance reactance tube is greatly changed along with the first control voltage ATUNE, so that the voltage-controlled oscillator has a wider tuning range.
In summary, compared with the voltage-controlled oscillator in the prior art, the voltage-controlled oscillator has the advantages that the oscillation frequency is improved, the oscillation can be started quickly, and the tuning range is wider.
It should be noted that, Q3, Q4, Q5 and Q6 in the buffer circuit in the embodiment shown in fig. 3 are implemented by transistors, it is understood that the transistor positions in the buffer circuit can also be implemented by MOS transistors, as shown in fig. 4, which is yet another embodiment of the high-frequency voltage-controlled oscillator provided by the present invention. The difference between fig. 4 and fig. 3 is that Q3, Q4, Q5 and Q6 in fig. 3 are changed to M3, M4, M5 and M6, respectively.
The buffer circuit includes: a third MOS transistor M3, a fourth MOS transistor M4, a fifth MOS transistor M5, a sixth MOS transistor M6, a seventh capacitor C7, an eighth capacitor C8, a fifth resistor R5, and a sixth resistor R6;
the grid electrode of the third MOS tube M3 is connected with the third node C, the drain electrode is connected with the power supply, and the source electrode is connected with the fifth node M;
the gate of the fourth MOS transistor M4 is connected to the fourth node D, the drain is connected to the power supply, and the source is connected to the sixth node N;
one end of the seventh capacitor C7 is connected to the fifth node M, and the other end is connected to the gate of the fifth MOS transistor M5;
the drain electrode of the fifth MOS transistor M5 is connected with the power supply, and the source electrode is grounded through the fifth resistor R5;
one end of the eighth capacitor C8 is connected to the sixth node N, and the other end is connected to the gate of the sixth MOS transistor M6;
the drain electrode of the sixth MOS transistor M6 is connected with the power supply, and the source electrode is grounded through the sixth resistor R6;
the source of the fifth MOS transistor M5 is a first output terminal NOUT of the voltage-controlled oscillator, and the source of the sixth MOS transistor M6 is a second output terminal POUT of the voltage-controlled oscillator;
the third node C is a first phase connection point of the resonance circuit and the buffer circuit; the fourth node D is a second connection point of the resonance circuit and the snubber circuit;
the fifth node M is a first phase connection point of the buffer circuit and the negative resistance circuit; and the sixth node N is a second connection point of the buffer circuit and the negative resistance circuit.
The working principle of fig. 4 is the same as that of fig. 3, and will not be described again.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.
Claims (10)
1. A high frequency voltage controlled oscillator, comprising: the circuit comprises a resonant circuit, a negative resistance circuit, a current source circuit and a buffer circuit;
the resonant circuit is used for generating an oscillation signal of the voltage-controlled oscillator, and is an inductance-capacitance resonant circuit, wherein a capacitor adopts an MOS capacitive reactance tube;
the negative resistance circuit is used for generating negative resistance so as to counteract positive resistance generated by the resonance circuit;
the current source circuit is used for generating a current for the voltage-controlled oscillator to work; the current source circuit comprises a seventh heterojunction bipolar transistor; an emitter electrode of the seventh heterojunction bipolar transistor is grounded, and a collector electrode of the seventh heterojunction bipolar transistor is connected with a negative resistance circuit; the base electrode of the seventh heterojunction bipolar transistor is connected with a third control voltage;
and the buffer circuit is used for buffering the oscillation signal generated by the resonance circuit and then outputting the buffered oscillation signal so as to isolate the buffered oscillation signal from an external signal.
2. The high frequency voltage controlled oscillator of claim 1, wherein the resonant circuit comprises: the circuit comprises a differential inductor, a first MOS capacitive reactance tube, a second MOS capacitive reactance tube, a third capacitor, a fourth capacitor, a first resistor and a second resistor;
one end of the differential inductor is connected with the third node, and the other end of the differential inductor is connected with the fourth node; a tap of the differential inductor is connected with a power supply;
the drain electrode and the source electrode of the first MOS capacitive reactance tube are both connected with a first control voltage, and the drain electrode and the source electrode of the second MOS capacitive reactance tube are both connected with the first control voltage;
the grid electrode of the first MOS capacitive reactance tube is connected with a first node, and the grid electrode of the second MOS capacitive reactance tube is connected with a second node;
two ends of the first resistor are respectively connected with the first node and the ground; two ends of the second resistor are respectively connected with the second node and the ground;
two ends of the third capacitor are respectively connected with the first node and the third node, and two ends of the fourth capacitor are respectively connected with the second node and the fourth node;
the third node is a first phase connection point of the resonance circuit and the buffer circuit and outputs a first resonance signal; the fourth node is a second connection point of the resonant circuit and the buffer circuit, and outputs a second resonant signal.
3. The high frequency voltage controlled oscillator of claim 1, wherein the buffer circuit comprises: the third bipolar transistor, the fourth bipolar transistor, the fifth bipolar transistor, the sixth bipolar transistor, the seventh capacitor, the eighth capacitor, the fifth resistor and the sixth resistor;
the base electrode of the third bipolar transistor is connected with a third node, the collector electrode of the third bipolar transistor is connected with the power supply, and the emitter electrode of the third bipolar transistor is connected with a fifth node;
the base electrode of the fourth bipolar transistor is connected with a fourth node, the collector electrode of the fourth bipolar transistor is connected with the power supply, and the emitter electrode of the fourth bipolar transistor is connected with a sixth node;
one end of the seventh capacitor is connected with the fifth node, and the other end of the seventh capacitor is connected with the base electrode of the fifth bipolar transistor;
a collector of the fifth bipolar transistor is connected with the power supply, and an emitter of the fifth bipolar transistor is grounded through the fifth resistor;
one end of the eighth capacitor is connected with the sixth node, and the other end of the eighth capacitor is connected with the base electrode of the sixth bipolar transistor;
a collector of the sixth bipolar transistor is connected with the power supply, and an emitter of the sixth bipolar transistor is grounded through the sixth resistor;
an emitter electrode of the fifth bipolar transistor is a first output end of the voltage-controlled oscillator, and an emitter electrode of the sixth bipolar transistor is a second output end of the voltage-controlled oscillator; wherein,
the third node is a first phase connection point of the resonance circuit and the buffer circuit; the fourth node is a second connection point of the resonance circuit and the buffer circuit;
the fifth node is a first phase connection point of the buffer circuit and the negative resistance circuit; and the sixth node is a second connection point of the buffer circuit and the negative resistance circuit.
4. The high frequency voltage controlled oscillator of claim 1, wherein the negative resistance circuit comprises: the first bipolar transistor, the second bipolar transistor, the fifth capacitor, the sixth capacitor, the third resistor, the fourth resistor and the ninth capacitor;
the collector of the first bipolar transistor is connected with a fifth node, the emitter of the first bipolar transistor is connected with the current source circuit, and the base of the first bipolar transistor is connected with a second control voltage through the third resistor;
the collector of the second bipolar transistor is connected with a sixth node, the emitter of the second bipolar transistor is connected with the current source, and the base of the second bipolar transistor is connected with the second control voltage through the fourth resistor;
two ends of the ninth capacitor are respectively connected with the second control voltage and the ground;
one end of the fifth capacitor is connected with the fifth node, and the other end of the fifth capacitor is connected with the base electrode of the second bipolar transistor;
one end of the sixth capacitor is connected with the sixth node, and the other end of the sixth capacitor is connected with the base electrode of the first bipolar transistor; wherein,
the fifth node is a first phase connection point of the buffer circuit and the negative resistance circuit; the sixth node is a second connection point of the buffer circuit and the negative resistance circuit;
the emitter of the first bipolar transistor is a first end of the negative resistance circuit, and the emitter of the second bipolar transistor is a second end of the negative resistance circuit.
5. The high frequency voltage controlled oscillator of claim 2, wherein the first and second MOS varactors operate in an accumulation region or a depletion region.
6. The high frequency voltage controlled oscillator of claim 2, wherein the third and fourth capacitors have a capacitance value at least ten times greater than the capacitance values of the first and second MOS capacitive reactance tubes.
7. The high frequency voltage controlled oscillator of claim 4, wherein the first bipolar transistor and the second bipolar transistor operate in a forward operating region.
8. The high frequency voltage controlled oscillator of claim 1, wherein the seventh heterojunction bipolar transistor operates in a forward operating region.
9. The high frequency voltage controlled oscillator of claim 3, wherein the third bipolar transistor, the fourth bipolar transistor, the fifth bipolar transistor and the sixth bipolar transistor operate in a forward operating region.
10. The high frequency voltage controlled oscillator of claim 1, wherein the buffer circuit comprises: the third MOS tube, the fourth MOS tube, the fifth MOS tube, the sixth MOS tube, the seventh capacitor, the eighth capacitor, the fifth resistor and the sixth resistor;
the grid electrode of the third MOS tube is connected with a third node, the drain electrode of the third MOS tube is connected with the power supply, and the source electrode of the third MOS tube is connected with a fifth node;
the grid electrode of the fourth MOS tube is connected with a fourth node, the drain electrode of the fourth MOS tube is connected with the power supply, and the source electrode of the fourth MOS tube is connected with a sixth node;
one end of the seventh capacitor is connected with the fifth node, and the other end of the seventh capacitor is connected with the base electrode of the fifth bipolar transistor;
the drain electrode of the fifth MOS tube is connected with the power supply, and the source electrode of the fifth MOS tube is grounded through the fifth resistor;
one end of the eighth capacitor is connected with the sixth node, and the other end of the eighth capacitor is connected with the base electrode of the sixth MOS tube;
the drain electrode of the sixth MOS tube is connected with the power supply, and the source electrode of the sixth MOS tube is grounded through the sixth resistor;
the source electrode of the fifth MOS transistor is a first output end of the voltage-controlled oscillator, and the source electrode of the sixth MOS transistor is a second output end of the voltage-controlled oscillator; wherein,
the third node is a first phase connection point of the resonance circuit and the buffer circuit; the fourth node is a second connection point of the resonance circuit and the buffer circuit;
the fifth node is a first phase connection point of the buffer circuit and the negative resistance circuit; and the sixth node is a second connection point of the buffer circuit and the negative resistance circuit.
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| WO2014044029A1 (en) * | 2012-09-21 | 2014-03-27 | 中国科学院微电子研究所 | Low-noise voltage-controlled oscillator |
| CN104184415A (en) * | 2013-05-22 | 2014-12-03 | 上海华虹宏力半导体制造有限公司 | Voltage controlled oscillator |
| CN110113008A (en) * | 2019-05-31 | 2019-08-09 | 华讯方舟科技有限公司 | A kind of Voltage-Controlled oscillation circuit and voltage controlled oscillator |
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| CN1645739A (en) * | 2004-01-20 | 2005-07-27 | 松下电器产业株式会社 | Voltage controlled oscillator |
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| CN1645739A (en) * | 2004-01-20 | 2005-07-27 | 松下电器产业株式会社 | Voltage controlled oscillator |
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Effective date of registration: 20190114 Address after: 266101 Songling Road 169, Laoshan District, Qingdao City, Shandong Province Patentee after: Zhongke Xinyun Microelectronics Technology Co.,Ltd. Address before: No. 3, North Tu Cheng West Road, Chaoyang District, Beijing Patentee before: Institute of Microelectronics of the Chinese Academy of Sciences |