CN109995325B - Low-noise RC oscillator - Google Patents

Low-noise RC oscillator Download PDF

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Publication number
CN109995325B
CN109995325B CN201811634025.1A CN201811634025A CN109995325B CN 109995325 B CN109995325 B CN 109995325B CN 201811634025 A CN201811634025 A CN 201811634025A CN 109995325 B CN109995325 B CN 109995325B
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circuit
nmos tube
tube
electrode
oscillator
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CN109995325A (en
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袁博群
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Chengdu Analog Circuit Technology Inc
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Chengdu Analog Circuit Technology Inc
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/02—Details
    • H03B5/04—Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/20—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising resistance and either capacitance or inductance, e.g. phase-shift oscillator
    • H03B5/24—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising resistance and either capacitance or inductance, e.g. phase-shift oscillator active element in amplifier being semiconductor device
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Abstract

The invention discloses a low-noise RC oscillator, and relates to the technical field of integrated circuits. The low-noise RC oscillator comprises a phase-locked loop, wherein the phase-locked loop comprises a low-pass filter circuit, a voltage-controlled oscillator circuit, a differential-to-single-ended circuit and a frequency divider circuit which is respectively connected with the voltage-controlled oscillator circuit and the differential-to-single-ended circuit, and the low-noise RC oscillator is characterized by further comprising a switched capacitor circuit which is connected with the frequency divider circuit, a current mirror circuit and a current comparator circuit which are connected with the low-pass filter circuit, and a bias current source and a voltage stabilizing circuit which are also connected with the current comparator circuit. According to the technical scheme, the low-pass filter circuit is used for filtering noise in the RC oscillator, and meanwhile, the phase-locked loop bandwidth is used for inhibiting noise generated by the voltage-controlled oscillator circuit, so that phase noise in the RC oscillator is greatly reduced, and the requirement of a high-precision system is met.

Description

Low-noise RC oscillator
Technical Field
The invention relates to the technical field of integrated circuits, in particular to a low-noise RC oscillator.
Background
With the rapid development of integrated circuits, in phase-locked loops, crystal oscillator-free USB, high-speed ADC and radio frequency systems, high-power supply voltage suppression and low-noise reference clock generators are increasingly used in the field of low-cost and low-power consumption NB-IOT (Narrow Band Internet of Things ). The clock generator provides accurate system clocks or counters for the NB-IOT equipment and the portable medical equipment, so that the system can work normally and stably, and the change of temperature and power supply voltage is the most critical factor affecting the frequency stability of the on-chip RC oscillator. Therefore, it is desirable to design an RC oscillator that is low in noise and insensitive to temperature and supply voltage variations.
Disclosure of Invention
The main object of the present invention is to provide a low noise RC oscillator aimed at reducing the phase noise of the oscillator.
In order to achieve the above object, the present invention provides a low noise RC oscillator, comprising a phase-locked loop, wherein the phase-locked loop comprises a low pass filter circuit, a voltage-controlled oscillator circuit, a differential to single-ended circuit, and a frequency divider circuit respectively connected to the voltage-controlled oscillator circuit and the differential to single-ended circuit, the low noise RC oscillator further comprises a switched capacitor circuit connected to the frequency divider circuit, a current mirror circuit and a current comparator circuit connected to the low pass filter circuit, and the current comparator circuit is further connected to a bias current source and a voltage stabilizing circuit;
the bias current source provides a bias power supply for the current comparator circuit, the current comparator circuit outputs a control voltage to the low-pass filter, and the voltage-controlled oscillator circuit generates clock frequency to control the switch capacitor circuit to charge/discharge; the voltage-controlled oscillator circuit outputs the clock frequency to the differential-to-single-ended circuit so that the differential-to-single-ended circuit outputs a clock signal.
Preferably, the current mirror circuit includes an operational amplifier, a first PMOS transistor, a second PMOS transistor, a third PMOS transistor and a fourth PMOS transistor, wherein the first PMOS transistor and the second PMOS transistor are respectively connected to two input ends of the operational amplifier, and the third PMOS transistor and the fourth PMOS transistor are respectively connected to two output ends of the operational amplifier.
Preferably, the source electrode of the first PMOS transistor and the source electrode of the second PMOS transistor are connected to a power supply, the gate electrodes are connected to each other, and the drain electrodes are respectively connected to two input ends of the operational amplifier;
the grid electrodes of the third PMOS tube and the fourth PMOS tube are respectively connected with two output ends of the operational amplifier; the source electrode of the third PMOS tube is connected with the drain electrode of the first PMOS tube, and the drain electrode of the third PMOS tube is respectively connected with the grid electrode of the first PMOS tube and the current comparator circuit; and the source electrode of the fourth PMOS tube is connected with the drain electrode of the second PMOS tube, and the drain electrode of the fourth PMOS tube is respectively connected with the current comparator circuit and the low-pass filter circuit.
Preferably, the current comparator circuit comprises a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube, a fifth NMOS tube and a sixth NMOS tube;
the drain electrode of the first NMOS tube is connected with the drain electrode of the third PMOS tube, the grid electrode of the first NMOS tube is connected with the drain electrode of the third NMOS tube, and the source electrode of the first NMOS tube is connected with the grid electrode of the fifth NMOS tube; the drain electrode of the second NMOS tube is connected with the drain electrode of the fourth PMOS tube, the grid electrode of the second NMOS tube is connected with the drain electrode of the fourth NMOS tube, and the source electrode of the second NMOS tube is connected with the grid electrode of the sixth NMOS tube;
the drain electrode of the third NMOS tube is connected with the bias current source, the source electrode of the third NMOS tube is connected with the drain electrode of the fifth NMOS tube, and the grid electrode of the third NMOS tube is connected with the grid electrode of the fourth NMOS tube; the drain electrode of the fourth NMOS tube is connected with the bias current source, and the source electrode of the fourth NMOS tube is connected with the drain electrode of the sixth NMOS tube;
and the sources of the fifth NMOS tube and the sixth NMOS tube are grounded, and the grid electrode is connected to the voltage stabilizing circuit.
Preferably, the current comparator circuit is further connected with a variable resistor, one end of the variable resistor is connected to the gate of the fifth NMOS, and the other end of the variable resistor is grounded.
Preferably, the voltage stabilizing circuit comprises a first resistor and a second resistor; one end of the first resistor is connected to the grid electrode of the fifth NMOS tube, and the other end of the first resistor is grounded; one end of the second resistor is connected to the grid electrode of the sixth NMOS tube, and the other end of the second resistor is grounded.
Preferably, the resistance value of the first resistor is equal to the resistance value of the second resistor.
Preferably, the bias current source includes a first bias current, a second bias current, a first capacitor and a second capacitor, the first bias current is connected to the drain of the fourth NMOS transistor, and the second bias current is connected to the drain of the third NMOS transistor;
one end of the first capacitor is connected with the first bias current, and the other end of the first capacitor is grounded; one end of the second capacitor is connected with the second bias current, and the other end of the second capacitor is grounded.
Preferably, the switched capacitor circuit includes a third capacitor, and a first switch and a second switch connected to the frequency divider circuit, one end of the first switch is connected to the gate of the sixth NMOS transistor, the other end of the first switch is connected to one end of the third capacitor and one end of the second switch, and the other end of the third capacitor and the other end of the second switch are grounded.
According to the technical scheme, the current comparator circuit outputs control voltage to the phase-locked loop, so that the voltage-controlled oscillator circuit generates clock frequency to control the switch capacitor circuit to charge/discharge; noise in the RC oscillator is filtered through the low-pass filter circuit, and meanwhile, the phase-locked loop bandwidth suppresses noise generated by the voltage-controlled oscillator circuit, so that phase noise in the RC oscillator is greatly reduced, and the requirement of a high-precision system is met.
Drawings
Fig. 1 is a schematic circuit diagram of a low noise RC oscillator of the present invention.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The invention is further described below with reference to the accompanying drawings.
The embodiment of the invention provides a low-noise RC oscillator, as shown in figure 1, which comprises a phase-locked loop, wherein the phase-locked loop comprises a low-pass filter circuit LPF, a voltage-controlled oscillator circuit VCO, a differential to single-ended circuit DTS, a frequency divider circuit N respectively connected with the voltage-controlled oscillator circuit VCO and the differential to single-ended circuit DTS, a switch capacitor circuit connected with the frequency divider circuit N, a current mirror circuit and a current comparator circuit connected with the low-pass filter circuit LPF, and a bias current source and a voltage stabilizing circuit;
the bias current source provides a bias power supply for the current comparator circuit, the current comparator circuit outputs a control voltage to the low-pass filter, and the voltage-controlled oscillator circuit VCO generates a clock frequency to control the switch capacitor circuit to charge/discharge; the voltage-controlled oscillator circuit VCO outputs the clock frequency to the differential to single-ended circuit DTS, so that the differential to single-ended circuit DTS outputs the clock signal clk.
Specifically, the phase-locked loop includes a low-pass filter circuit LPF, a differential to single-ended circuit DTS, a voltage-controlled oscillator circuit VCO, and a frequency divider circuit N, all of which are common circuits in the prior art.
Preferably, the current mirror circuit includes an operational amplifier OP, a first PMOS transistor MP1, a second PMOS transistor MP2, a third PMOS transistor MP3, and a fourth PMOS transistor MP4, where the first PMOS transistor MP1 and the second PMOS transistor MP2 are respectively connected to two input ends of the operational amplifier OP, and the third PMOS transistor MP3 and the fourth PMOS transistor MP4 are respectively connected to two output ends of the operational amplifier OP.
In a specific embodiment, the operational amplifier OP is a gain-increasing operational amplifier for increasing the output impedance of the control voltage output by the current comparator circuit to increase the power supply rejection capability of the oscillator.
Preferably, the source electrode of the first PMOS transistor MP1 and the source electrode of the second PMOS transistor MP2 are connected to a power supply, the gate electrodes are connected to each other, and the drain electrodes are respectively connected to two input ends of the operational amplifier OP;
the grid electrodes of the third PMOS tube MP3 and the fourth PMOS tube MP4 are respectively connected with two output ends of the operational amplifier OP; the source electrode of the third PMOS tube MP3 is connected with the drain electrode of the first PMOS tube MP1, and the drain electrode is respectively connected with the grid electrode of the first PMOS tube MP1 and the current comparator circuit; the source electrode of the fourth PMOS MP4 is connected to the drain electrode of the second PMOS MP2, and the drain electrode is connected to the current comparator circuit and the low pass filter circuit LPF, respectively.
Preferably, the current comparator circuit includes a first NMOS transistor MN1, a second NMOS transistor MN2, a third NMOS transistor MN3, a fourth NMOS transistor MN4, a fifth NMOS transistor MN5, and a sixth NMOS transistor MN6; the drain electrode of the first NMOS tube MN1 is connected with the drain electrode of the third PMOS tube MP3, the grid electrode is connected with the drain electrode of the third NMOS tube MN3, and the source electrode is connected with the grid electrode of the fifth NMOS tube MN 5;
the drain electrode of the second NMOS tube MN2 is connected with the drain electrode of the fourth PMOS tube MP4, the grid electrode of the second NMOS tube MN2 is connected with the drain electrode of the fourth NMOS tube MN4, and the source electrode of the second NMOS tube MN2 is connected with the grid electrode of the sixth NMOS tube MN6; the drain electrode of the third NMOS tube MN3 is connected with the bias current source, the source electrode of the third NMOS tube MN3 is connected with the drain electrode of the fifth NMOS tube MN5, and the grid electrode of the third NMOS tube MN4 is connected with the grid electrode of the fourth NMOS tube;
the drain electrode of the fourth NMOS tube MN4 is connected with the bias current source, and the source electrode of the fourth NMOS tube MN4 is connected with the drain electrode of the sixth NMOS tube MN6; the sources of the fifth NMOS tube MN5 and the sixth NMOS tube MN6 are grounded, and the grid is connected to the voltage stabilizing circuit.
The current mirror circuit and the current comparator circuit have smaller noise, so that the capacitance value of the low-pass filter can be reduced, the low-frequency noise in the RC oscillator is filtered through the low-pass filter circuit, and meanwhile, the loop bandwidth is increased to inhibit the high-frequency noise generated by the voltage-controlled oscillator circuit, so that the noise of the whole RC oscillator is greatly reduced.
Preferably, the bias current source includes a first bias current Iref1, a second bias current Iref2, a first capacitor C1 and a second capacitor C2, the first bias current Iref1 is connected to the drain of the fourth NMOS transistor MN4, and the second bias current Iref2 is connected to the drain of the third NMOS transistor MN 3;
one end of the first capacitor C1 is connected to the first bias current Iref1, and the other end of the first capacitor C is grounded; one end of the second capacitor C2 is connected to the second bias current Iref2, and the other end is grounded.
The first bias current Iref1 and the second bias current Iref2 provide bias currents for the third NMOS transistor MN3 and the fourth NMOS transistor MN4, respectively. The first capacitor C1 and the second capacitor C2 control the first bias current Iref1 and the second bias current Iref2 to stabilize, respectively, so as to provide a stable bias current source for the current comparator circuit.
Preferably, the current comparator circuit is further connected to a variable resistor r_t, one end of the variable resistor r_t is connected to the gate of the fifth NMOS MN5, and the other end is grounded. The third terminal of the variable resistor r_t may be connected to the fifth NMOS transistor MN5 or ground according to an embodiment.
The variable resistor R_t is combined with the switched capacitor circuit to generate different output frequencies, and generates different control voltages through the current comparator circuit to control the voltage-controlled oscillator circuit VCO to generate different phase clocks to control the switched capacitor circuit. The output frequency is calculated by the equation f=1/RC, where f is the output frequency, R is the resistance value of the variable resistor r_t, and C is the capacitance value in the switched-capacitor circuit.
Preferably, the voltage stabilizing circuit comprises a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected to the gate of the fifth NMOS tube MN5, and the other end of the first resistor R1 is grounded; one end of the second resistor R2 is connected to the gate of the sixth NMOS MN6, and the other end is grounded.
Preferably, the resistance of the first resistor R1 is equal to the resistance of the second resistor R2.
The voltage stabilizing sub-circuit is combined with the current comparator circuit to provide two-point clamping voltages of Vx1 and Vx2 for the RC oscillator, so that the two-point voltages of Vx1 and Vx2 are equal as much as possible, and dynamic balance is achieved.
Preferably, the switched capacitor circuit includes a third capacitor C3 and a first switch S1 and a second switch S2 connected to the frequency divider circuit N, one end of the first switch S1 is connected to the gate of the sixth NMOS transistor MN6, the other end is connected to one end of the third capacitor C3 and one end of the second switch S2, and the other end of the third capacitor C3 and the other end of the second switch S2 are grounded.
The frequency divider circuit N receives different phase clocks generated by the voltage-controlled oscillator circuit VCO, and controls the opening and closing of the first switch S1 and the second switch S2 respectively to control the charging and discharging of the third capacitor C3.
It should be understood that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structures or equivalent processes using the descriptions of the present invention and the accompanying drawings, or direct or indirect application in other related technical fields are included in the scope of the present invention.

Claims (6)

1. The low-noise RC oscillator comprises a phase-locked loop, wherein the phase-locked loop comprises a low-pass filter circuit, a voltage-controlled oscillator circuit, a differential-to-single-ended circuit and a frequency divider circuit which are connected with the voltage-controlled oscillator circuit and the differential-to-single-ended circuit respectively, and the low-noise RC oscillator is characterized by further comprising a switched capacitor circuit which is connected with the frequency divider circuit, a current mirror circuit and a current comparator circuit which are connected with the low-pass filter circuit, and a bias current source and a voltage stabilizing circuit which are connected with the current comparator circuit;
the bias current source provides a bias power supply for the current comparator circuit, the current comparator circuit outputs a control voltage to the low-pass filter, and the voltage-controlled oscillator circuit generates clock frequency to control the switch capacitor circuit to charge/discharge; the voltage-controlled oscillator circuit outputs the clock frequency to the differential-to-single-ended circuit so that the differential-to-single-ended circuit outputs a clock signal;
the current mirror circuit comprises an operational amplifier, a first PMOS tube, a second PMOS tube, a third PMOS tube and a fourth PMOS tube, wherein the first PMOS tube and the second PMOS tube are respectively connected with two input ends of the operational amplifier, and the third PMOS tube and the fourth PMOS tube are respectively connected with two output ends of the operational amplifier;
the source electrode of the first PMOS tube and the source electrode of the second PMOS tube are connected with a power supply, the grid electrodes are connected with each other, and the drain electrodes are respectively connected with two input ends of the operational amplifier;
the grid electrodes of the third PMOS tube and the fourth PMOS tube are respectively connected with two output ends of the operational amplifier; the source electrode of the third PMOS tube is connected with the drain electrode of the first PMOS tube, and the drain electrode of the third PMOS tube is respectively connected with the grid electrode of the first PMOS tube and the current comparator circuit; the source electrode of the fourth PMOS tube is connected with the drain electrode of the second PMOS tube, and the drain electrode of the fourth PMOS tube is respectively connected with the current comparator circuit and the low-pass filter circuit;
the current comparator circuit comprises a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube, a fifth NMOS tube and a sixth NMOS tube;
the drain electrode of the first NMOS tube is connected with the drain electrode of the third PMOS tube, the grid electrode of the first NMOS tube is connected with the drain electrode of the third NMOS tube, and the source electrode of the first NMOS tube is connected with the grid electrode of the fifth NMOS tube; the drain electrode of the second NMOS tube is connected with the drain electrode of the fourth PMOS tube, the grid electrode of the second NMOS tube is connected with the drain electrode of the fourth NMOS tube, and the source electrode of the second NMOS tube is connected with the grid electrode of the sixth NMOS tube;
the drain electrode of the third NMOS tube is connected with the bias current source, the source electrode of the third NMOS tube is connected with the drain electrode of the fifth NMOS tube, and the grid electrode of the third NMOS tube is connected with the grid electrode of the fourth NMOS tube; the drain electrode of the fourth NMOS tube is connected with the bias current source, and the source electrode of the fourth NMOS tube is connected with the drain electrode of the sixth NMOS tube;
and the sources of the fifth NMOS tube and the sixth NMOS tube are grounded, and the grid electrode is connected to the voltage stabilizing circuit.
2. The low noise RC oscillator of claim 1 wherein the current comparator circuit is further connected to a variable resistor, one end of the variable resistor is connected to the gate of the fifth NMOS transistor, and the other end is grounded.
3. The low noise RC oscillator of claim 1, wherein the voltage stabilizing circuit comprises a first resistor and a second resistor; one end of the first resistor is connected to the grid electrode of the fifth NMOS tube, and the other end of the first resistor is grounded; one end of the second resistor is connected to the grid electrode of the sixth NMOS tube, and the other end of the second resistor is grounded.
4. A low noise RC oscillator according to claim 3, wherein the first resistor has a value equal to the second resistor.
5. The low noise RC oscillator of claim 1 wherein the bias current source comprises a first bias current, a second bias current, a first capacitance, and a second capacitance, the first bias current being connected to the drain of the fourth NMOS transistor, the second bias current being connected to the drain of the third NMOS transistor;
one end of the first capacitor is connected with the first bias current, and the other end of the first capacitor is grounded; one end of the second capacitor is connected with the second bias current, and the other end of the second capacitor is grounded.
6. The low noise RC oscillator of claim 1, wherein the switched capacitor circuit comprises a third capacitor and a first switch and a second switch connected to the frequency divider circuit, one end of the first switch is connected to the gate of the sixth NMOS transistor, the other end is connected to one end of the third capacitor and one end of the second switch, and the other end of the third capacitor and the other end of the second switch are grounded.
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Publication number Priority date Publication date Assignee Title
CN110492849B (en) * 2019-09-02 2023-07-28 成都锐成芯微科技股份有限公司 RC oscillating circuit
CN111181491B (en) * 2019-12-31 2023-07-28 成都锐成芯微科技股份有限公司 Clock generating circuit
CN111641410B (en) * 2020-06-22 2023-11-17 上海兆芯集成电路股份有限公司 Digital phase-locked loop

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5594388A (en) * 1995-06-07 1997-01-14 American Microsystems, Inc. Self-calibrating RC oscillator
CN203734655U (en) * 2014-02-21 2014-07-23 安徽钰鑫电子科技有限公司 Interference exciter having frequency band adjustable function
US9287823B1 (en) * 2014-09-15 2016-03-15 Nuvoton Technology Corporation Method and apparatus of a self-biased RC oscillator and ramp generator
CN107040210A (en) * 2017-05-31 2017-08-11 广东工业大学 A kind of RC oscillators and DC D/C power chip
CN107317567A (en) * 2016-04-26 2017-11-03 成都锐成芯微科技股份有限公司 The RC oscillating circuits of low-temperature coefficient output frequency

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2874766A1 (en) * 2004-09-02 2006-03-03 St Microelectronics Sa METHOD FOR CONFIGURING THE CLOCK SYSTEM OF A MICROCONTROLLER
KR100753666B1 (en) * 2006-06-01 2007-08-31 삼성전기주식회사 Micropower rc oscillator
CN101588178B (en) * 2008-05-23 2011-08-17 中芯国际集成电路制造(上海)有限公司 Self-biased phase-locked loop

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5594388A (en) * 1995-06-07 1997-01-14 American Microsystems, Inc. Self-calibrating RC oscillator
CN203734655U (en) * 2014-02-21 2014-07-23 安徽钰鑫电子科技有限公司 Interference exciter having frequency band adjustable function
US9287823B1 (en) * 2014-09-15 2016-03-15 Nuvoton Technology Corporation Method and apparatus of a self-biased RC oscillator and ramp generator
CN107317567A (en) * 2016-04-26 2017-11-03 成都锐成芯微科技股份有限公司 The RC oscillating circuits of low-temperature coefficient output frequency
CN107040210A (en) * 2017-05-31 2017-08-11 广东工业大学 A kind of RC oscillators and DC D/C power chip

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
一种低噪声CMOS差分环型压控振荡器的设计和分析;程梦璋等;《电子器件》;20080615(第03期);824-826 *
一种超低功耗RC振荡器设计;胡安俊等;《半导体技术》;20180703(第07期);15-21 *
创新单级环形振荡器的研制;彭杰等;《半导体技术》;20091103(第11期);1144-1147 *

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