CN117544116A - Noise circulation oscillator with wide frequency range - Google Patents

Abstract

The invention discloses a wide-frequency-range noise cyclic oscillator, which comprises an upper frequency band oscillator and a lower frequency band oscillator which are of the same topology, wherein the upper frequency band oscillator and the lower frequency band oscillator are coupled, the resonant frequencies of the upper frequency band oscillator and the lower frequency band oscillator are different, the upper frequency band oscillator comprises a first active core circuit, a first LC resonant circuit and a first switch capacitor array which are mutually connected in parallel, and the lower frequency band oscillator comprises a second active core circuit, a second LC resonant circuit and a second switch capacitor array which are mutually connected in parallel. The invention can realize wide frequency tuning and low phase noise simultaneously by noise circulation technology and the coupling of the upper and lower frequency band oscillators.

Description

A wide frequency range noise cyclic oscillator

Technical field

The invention relates to the field of microelectronics technology, and in particular to a wide frequency range noise cyclic oscillator.

Background technique

Voltage-Controlled Oscillator (VCO) is an important component in electronic circuit design. It is widely used in wireless communications, radio frequency signal generation, clock signal generation and other fields. Designing a voltage-controlled oscillator requires comprehensive consideration of frequency range, tuning performance, noise performance, power consumption and other factors to meet the needs of different application fields. Currently, it is a huge challenge for voltage-controlled oscillators to maintain low phase noise over a wide frequency tuning range.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a wide frequency range noise cyclic oscillator to solve the problem of difficulty in maintaining low phase noise in a voltage controlled oscillator over a wide frequency tuning range.

In order to solve the above technical problems, the present invention is implemented by adopting the following solutions:

The invention provides a wide frequency range noise cyclic oscillator, including an upper frequency band oscillator and a lower frequency band oscillator of the same topology, coupling of the upper frequency band oscillator and lower frequency band oscillator, and resonance of the upper frequency band oscillator and lower frequency band oscillator. The frequencies are different. The upper frequency band oscillator includes a first active core circuit, a first LC resonant circuit and a first switched capacitor array connected in parallel. The lower frequency band oscillator includes a second active core circuit and a second LC resonant circuit connected in parallel. and a second switched capacitor array.

Further, the first active core circuit includes a first transistor (101), a second transistor (103), a third transistor (105) and a fourth transistor (107). The gate and source of the first transistor (101) The gate electrode of the fourth transistor (107) and the source electrode of the third transistor (105) are respectively connected, and the gate electrode and source electrode of the second transistor (103) are respectively connected with the gate electrode of the third transistor (105) and the fourth transistor (105). 107), the sources of the first transistor (101) and the third transistor (105) are connected to the inductive load terminal of the upper frequency band oscillator, and the sources of the second transistor (103) and the fourth transistor (107) are connected The inductive load end of the other channel of the lower frequency band oscillator, the drain of the first transistor (101) and the drain of the second transistor (103) are respectively connected to the power supply voltage, and the sources of the first transistor (101) and the third transistor (105) The first transistor (101) and the second transistor (103) form a common drain, and the third transistor (105) and the fourth transistor (107) A cross-coupling circuit is formed, and the common drain and cross-coupling circuit form a noise circulation structure.

Further, the second active core circuit includes a fifth transistor (111), a sixth transistor (113), a seventh transistor (115) and an eighth transistor (117). The gate and source of the fifth transistor (111) The gate electrode of the eighth transistor (117) and the source electrode of the seventh transistor (115) are respectively connected. The gate electrode and source electrode of the sixth transistor (113) are respectively connected with the gate electrode of the seventh transistor (115) and the eighth transistor (115). 117), the sources of the fifth transistor (111) and the seventh transistor (115) are connected to the inductive load terminal of the upper frequency band oscillator, and the sources of the sixth transistor (113) and the eighth transistor (117) are connected The inductive load end of the other channel of the lower frequency band oscillator, the drain of the fifth transistor (111) and the drain of the sixth transistor (113) are respectively connected to the power supply voltage, and the sources of the fifth transistor (111) and the seventh transistor (115) The fifth transistor (111) and the sixth transistor (113) form a common drain, and the seventh transistor (115) and the eighth transistor (117) A cross-coupling circuit is formed, and the common drain and cross-coupling circuit form a noise circulation structure.

Further, the first LC resonant circuit includes a third transistor (105), a fourth transistor (107), a first variable capacitor (401), a second variable capacitor (402) and a first capacitor (400). The third The transistor (105) and the fourth transistor (107) are cross-coupled, the first variable capacitor (401) and the second variable capacitor (402) are connected in series and in parallel with the first capacitor (400) to form a first parallel circuit, the first parallel circuit One end of the circuit is connected to the output VCON terminal, the other end is connected to the output VCOP terminal, and the control voltage Vc is connected between the first variable capacitor (401) and the second variable capacitor (402).

Further, the second LC resonant circuit includes a seventh transistor (115), an eighth transistor (117), a third variable capacitor (411), a fourth variable capacitor (412) and a second capacitor (410). The seventh The transistor (115) and the eighth transistor (117) are cross-coupled, the third variable capacitor (411) and the fourth variable capacitor (412) are connected in series and in parallel with the second capacitor (410) to form a second parallel circuit, and the second parallel circuit is One end of the circuit is connected to the output VCON terminal, the other end is connected to the output VCOP terminal, and the third variable capacitor (411) and the fourth variable capacitor (412) are connected to the control voltage Vc in between.

Further, the inductive load end of the upper frequency band oscillator includes a first inductor (201), a second inductor (202), a fifth resistor (301) and a sixth resistor (302). The first inductor (201), the second inductor (202), the fifth resistor (301) and the sixth resistor (302) form a circuit bias load, one end of the first inductor (201) is connected to one end of the fifth resistor (301), and the other end is connected to the first transistor (101) ) and the source of the third transistor (105), one end of the second inductor (202) is connected to one end of the sixth resistor (302), and the other end is connected to the sources of the second transistor (103) and the fourth transistor (107) , the other end of the fifth resistor (301) is connected to the other end of the sixth resistor (302) and grounded.

Further, the inductive load end of the lower frequency band oscillator includes a third inductor (211), a fourth inductor (212), a seventh resistor (311) and an eighth resistor (312). The third inductor (211), the fourth inductor (212), the seventh resistor (311) and the eighth resistor (312) form a circuit bias load, one end of the third inductor (211) is connected to one end of the seventh resistor (311), and the other end is connected to the fifth transistor (111) ) and the source of the seventh transistor (115), one end of the fourth inductor (212) is connected to one end of the eighth resistor (312), and the other end is connected to the sources of the sixth transistor (113) and the eighth transistor (117) , the other end of the seventh resistor (311) is connected to the other end of the eighth resistor (312) and grounded.

Further, the upper frequency band oscillator and the lower frequency band oscillator are coupled through a transformer, and the coupling coefficient is K.

Compared with the prior art, the beneficial effects achieved by the present invention are: the present invention can simultaneously achieve wide frequency tuning and low phase noise through noise circulation technology and upper and lower frequency band oscillators.

Description of drawings

Figure 1 is a circuit diagram of a wide frequency range noise cyclic oscillator provided by an embodiment of the present invention;

Figure 2 is a circuit diagram of a noise cyclic oscillator provided by an embodiment of the present invention;

Implementation

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present invention, but cannot be used to limit the scope of the present invention.

As shown in Figures 1 and 2, this embodiment provides a wide frequency range noise cyclic oscillator, including an upper frequency band oscillator and a lower frequency band oscillator of the same topology; the upper frequency band oscillator and the lower frequency band oscillator are coupled; the upper frequency band The resonant frequencies of the oscillator and the lower frequency band oscillator are different; the upper frequency band oscillator includes a first active core circuit, a first LC resonant circuit and a first switched capacitor array connected in parallel, and the lower frequency band oscillator includes a second active core circuit connected in parallel with each other. The source core circuit, the second LC resonant circuit and the second switched capacitor array.

The first active core circuit is composed of MOS transistors to implement a negative resistance circuit. The first active core circuit includes transistor 101, transistor 103, transistor 105 and transistor 107. Among them, the gate and source of transistor 101 are respectively connected to the gate of transistor 107 and the source of transistor 105, and the gate and source of transistor 103 are respectively connected to the gate of transistor 105 and the source of transistor 107; transistor 101 and transistor 105 The source of transistor 103 and transistor 107 is connected to the inductive load terminal on the left. The drains of transistor 101 and transistor 103 are connected to the power supply voltage respectively. The sources of transistor 101 and transistor 105 are connected to the transistor. 103 and the source of transistor 107, transistor 101 and transistor 103 form a common drain, transistor 105 and transistor 107 form a cross-coupling circuit, and the common drain and the cross-coupling circuit form a noise circulation structure.

The inductive load end of the upper frequency band oscillator includes an inductor 201, an inductor 202, a resistor 301 and a resistor 302. The inductor 201, the inductor 202, the resistor 301 and the resistor 302 form a circuit bias load. Among them, one end of the inductor 201 is connected to one end of the resistor 301, and the other end is connected to the sources of the transistor 101 and the transistor 105. One end of the inductor 202 is connected to one end of the resistor 302, and the other end is connected to the sources of the transistor 103 and the transistor 107. The resistor 301 The other end of the resistor 302 is connected to the ground.

The first LC resonant circuit ensures oscillation through a circuit composed of capacitors, inductors and cross-coupling tubes. The first LC resonant circuit includes a transistor 105, a transistor 107, a variable capacitor 401, a variable capacitor 402, and a capacitor 400. Among them, the NMOS transistor 105 and the NMOS transistor 107 are cross-coupled to achieve negative resistance, compensate for the energy loss in the resonant circuit, and ensure that the upper frequency band oscillator can work normally. The drains of the transistor 105 and the transistor 107 are the output of the upper frequency band oscillator; variable Capacitor 401 and variable capacitor 402 are connected in series and in parallel with capacitor 400 to form a parallel circuit. One end of the parallel circuit is connected to the output VCON terminal, and the other end is connected to the output VCOP terminal. The intermediate control voltage Vc between variable capacitor 401 and variable capacitor 402 is passed through Vc controls the capacitance values of the variable capacitor 401 and the variable capacitor 402.

The first switched capacitor array 600 is used to change the frequency band of the upper frequency band oscillator together with the variable capacitor 401 and the variable capacitor 402, and includes a transistor 605, a capacitor 601, a capacitor 602, a resistor 603 and a resistor 604. Among them, the transistor 605 is connected between the capacitor 601 and the capacitor 602, the gate of the transistor 605 is connected and receives the external control signal, the capacitor 601 is connected to the source of the transistor 605, the capacitor 602 is connected to the drain of the transistor 605, and the source and drain of the transistor 605 are connected. Resistor 603 and resistor 604 are connected between them. When the gate logic value of the transistor 605 is 1, the transistor 605 is turned on and forms a connection between the capacitors 601 and 602, and the first switched capacitor array 600 is turned on; when the gate logic value of the transistor 605 is 0, the transistor 605 is turned off. To disconnect the capacitors 601 and 602, and turn off the first switched capacitor array 600.

The second active core circuit is composed of MOS transistors to implement a negative resistance circuit, including transistor 111, transistor 113, transistor 115 and transistor 117. Among them, the gate and source of transistor 111 are respectively connected to the gate of transistor 117 and the source of transistor 115, and the gate and source of transistor 113 are respectively connected to the gate of transistor 115 and the source of transistor 117; transistor 111 and transistor 115 The source of transistor 113 and transistor 117 is connected to the inductive load terminal on the left. The drains of transistor 111 and transistor 113 are connected to the power supply voltage respectively. The sources of transistor 111 and transistor 115 are connected to the transistor. 113 and the source of transistor 117, transistor 111 and transistor 113 form a common drain, transistor 115 and transistor 117 form a cross-coupling circuit, and the common drain and the cross-coupling circuit form a noise circulation structure.

The inductive load end of the lower frequency band oscillator includes an inductor 211, an inductor 212, a resistor 311 and a resistor 312. The inductor 211, the inductor 212, the resistor 311 and the resistor 312 form a circuit bias load. Among them, one end of the inductor 211 is connected to one end of the resistor 311, and the other end is connected to the sources of the transistor 111 and the transistor 115. One end of the inductor 212 is connected to one end of the resistor 312, and the other end is connected to the sources of the transistor 113 and the transistor 117. The resistor 311 The other end of the resistor 312 is connected to the ground.

The second LC resonant circuit ensures oscillation through a circuit composed of capacitors, inductors and cross-coupling tubes. The second LC resonant circuit includes a transistor 115 , a transistor 117 , a variable capacitor 411 , a variable capacitor 412 and a capacitor 410 . Among them, the NMOS transistor 115 and the NMOS transistor 117 are cross-coupled to achieve negative resistance, compensate for the energy loss in the resonant circuit, and ensure that the lower frequency band oscillator can work normally. The drains of the transistor 115 and the transistor 117 are the output of the lower frequency band oscillator; variable Capacitor 411 and variable capacitor 412 are connected in series and in parallel with capacitor 410 to form a parallel circuit. One end of the parallel circuit is connected to the output VCON terminal, and the other end is connected to the output VCOP terminal. The intermediate control voltage Vc between variable capacitor 411 and variable capacitor 412 is passed through Vc controls the capacitance values of the variable capacitor 411 and the variable capacitor 412.

The second switched capacitor array 610 is used to change the frequency band of the lower frequency band oscillator together with the variable capacitor 411 and the variable capacitor 412 . Since the upper frequency band oscillator and the lower frequency band oscillator have the same topology, the specific structure of the second switched capacitor array 610 refers to the first switched capacitor array 600 in FIG. 2, so the illustration is omitted.

By adjusting the respective capacitance values of the upper frequency band oscillator and the lower frequency band oscillator (i.e., the capacitance values of the variable capacitor 401, the variable capacitor 402, the variable capacitor 411, and the variable capacitor 412), the inductance-to-capacitance ratio of the circuit can be adjusted, that is, the oscillation is changed. frequency of the device. The upper frequency band oscillator and the lower frequency band oscillator are coupled through a transformer, and the coupling coefficient is K. The upper frequency band oscillator operates in the first frequency range and is implemented by utilizing the transistor 605 in the first switched capacitor array 600 to be controlled by external control signals 605 ₁ to 605 _n ; the lower frequency band oscillator operates in the second frequency range and utilizes the third The transistors 615 in the two switched capacitor arrays 610 are controlled by external control signals 615 ₁ to 615 _n ; the first frequency range is different from the second frequency range.

In summary, the wide frequency range noise cyclic oscillator of the present invention can simultaneously achieve wide frequency tuning and low phase noise through noise circulation technology and coupling of upper and lower frequency band oscillators.

The above are only preferred embodiments of the present invention. It should be noted that those of ordinary skill in the art can also make several improvements and modifications without departing from the technical principles of the present invention. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (8)

1. A wide frequency range noise cyclic oscillator, comprising an upper frequency band oscillator and a lower frequency band oscillator of the same topology, the upper frequency band oscillator and the lower frequency band oscillator being coupled, the upper frequency band oscillator and the lower frequency band oscillator having different resonant frequencies, the upper frequency band oscillator comprising a first active core circuit, a first LC resonant circuit, and a first switched capacitor array in parallel with each other, the lower frequency band oscillator comprising a second active core circuit, a second LC resonant circuit, and a second switched capacitor array in parallel with each other.

2. The wide frequency range noise circulating oscillator according to claim 1, wherein the first active core circuit comprises a first transistor (101), a second transistor (103), a third transistor (105) and a fourth transistor (107), the gate and the source of the first transistor (101) are respectively connected to the gate of the fourth transistor (107) and the source of the third transistor (105), the gate and the source of the second transistor (103) are respectively connected to the gate of the third transistor (105) and the source of the fourth transistor (107), the source of the first transistor (101) and the source of the third transistor (105) are connected to an inductive load end of one path of the upper band oscillator, the source of the second transistor (103) and the source of the fourth transistor (107) are connected to an inductive load end of the other path of the lower band oscillator, the drain of the first transistor (101) and the drain of the second transistor (103) are respectively connected to a power supply voltage, the source of the first transistor (101) and the source of the second transistor (103) are respectively connected to the source of the fourth transistor (107), the drain of the second transistor (103) and the drain of the fourth transistor (103) are respectively connected to the source of the fourth transistor (107), the first transistor (101) and the drain of the fourth transistor (107) are coupled together, and the common drain of the second transistor (101) are coupled together, and the common drain of the common source (107) forms a cross-coupled structure.

3. The wide frequency range noise circulating oscillator according to claim 1, wherein the second active core circuit comprises a fifth transistor (111), a sixth transistor (113), a seventh transistor (115) and an eighth transistor (117), the gate and the source of the fifth transistor (111) are respectively connected to the gate of the eighth transistor (117) and the source of the seventh transistor (115), the gate and the source of the sixth transistor (113) are respectively connected to the gate of the seventh transistor (115) and the source of the eighth transistor (117), the source of the fifth transistor (111) and the source of the seventh transistor (115) are connected to an inductive load terminal of one path of the upper band oscillator, the source of the sixth transistor (113) and the source of the eighth transistor (117) are connected to an inductive load terminal of the other path of the lower band oscillator, the drain of the fifth transistor (111) and the drain of the sixth transistor (113) are respectively connected to a power supply voltage, the source of the fifth transistor (111) and the source of the seventh transistor (115) are respectively connected to the gate of the sixth transistor (113) and the source of the eighth transistor (117), the fifth transistor (111) and the drain of the eighth transistor (117) are connected to the source of the fifth transistor (113) and the drain of the eighth transistor (117) are respectively, the common coupling structure is formed, and the common drain (drain and the common coupling structure is formed.

4. The wide frequency range noise circulating oscillator according to claim 1, characterized in that the first LC resonant circuit comprises a third transistor (105), a fourth transistor (107), a first variable capacitor (401), a second variable capacitor (402) and a first capacitor (400), the third transistor (105) and the fourth transistor (107) are cross-coupled, the first variable capacitor (401) and the second variable capacitor (402) are connected in series and are connected in parallel with the first capacitor (400) to form a first parallel circuit, one end of the first parallel circuit is connected to an output VCON terminal, the other end is connected to an output VCOP terminal, and the first variable capacitor (401) and the second variable capacitor (402) are connected in intermediate connection with a control voltage Vc.

5. The wide frequency range noise circulating oscillator according to claim 1, characterized in that the second LC resonant circuit comprises a seventh transistor (115), an eighth transistor (117), a third variable capacitor (411), a fourth variable capacitor (412) and a second capacitor (410), the seventh transistor (115) and the eighth transistor (117) are cross-coupled, the third variable capacitor (411) and the fourth variable capacitor (412) are connected in series and are connected in parallel with the second capacitor (410) to form a second parallel circuit, one end of the second parallel circuit is connected to an output VCON terminal, the other end is connected to an output VCOP terminal, and the third variable capacitor (411) and the fourth variable capacitor (412) are connected in intermediate to a control voltage Vc.

6. The wide frequency range noise circulating oscillator according to claim 2, wherein the inductive load end of the upper frequency band oscillator comprises a first inductor (201), a second inductor (202), a fifth resistor (301) and a sixth resistor (302), the first inductor (201), the second inductor (202), the fifth resistor (301) and the sixth resistor (302) form a circuit bias load, one end of the first inductor (201) is connected with one end of the fifth resistor (301), the other end is connected with sources of the first transistor (101) and the third transistor (105), one end of the second inductor (202) is connected with one end of the sixth resistor (302), the other end is connected with sources of the second transistor (103) and the fourth transistor (107), and the other end of the fifth resistor (301) is connected with the other end of the sixth resistor (302) and grounded.

7. A wide frequency range noise circulating oscillator according to claim 3, characterized in that the inductive load end of the lower frequency band oscillator comprises a third inductor (211), a fourth inductor (212), a seventh resistor (311) and an eighth resistor (312), the third inductor (211), the fourth inductor (212), the seventh resistor (311) and the eighth resistor (312) form a circuit bias load, one end of the third inductor (211) is connected with one end of the seventh resistor (311), the other end is connected with sources of the fifth transistor (111) and the seventh transistor (115), one end of the fourth inductor (212) is connected with one end of the eighth resistor (312), the other end is connected with sources of the sixth transistor (113) and the eighth transistor (117), and the other end of the seventh resistor (311) is connected with the other end of the eighth resistor (312) and grounded.

8. The wide frequency range noise circulating oscillator of claim 1, wherein the upper band oscillator and the lower band oscillator are coupled by a transformer, the coupling coefficient being K.