CN112217476A - Self-excited injection crystal oscillator - Google Patents
Self-excited injection crystal oscillator Download PDFInfo
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- CN112217476A CN112217476A CN202010933422.XA CN202010933422A CN112217476A CN 112217476 A CN112217476 A CN 112217476A CN 202010933422 A CN202010933422 A CN 202010933422A CN 112217476 A CN112217476 A CN 112217476A
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- circuit
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- comparator
- crystal oscillator
- injection
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- 239000013078 crystal Substances 0.000 title claims abstract description 52
- 238000002347 injection Methods 0.000 title claims abstract description 31
- 239000007924 injection Substances 0.000 title claims abstract description 31
- 230000010355 oscillation Effects 0.000 claims abstract description 16
- 239000010453 quartz Substances 0.000 claims abstract description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000003990 capacitor Substances 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 5
- 238000005516 engineering process Methods 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
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Classifications
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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
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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
- H03B5/30—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator
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- Oscillators With Electromechanical Resonators (AREA)
Abstract
The invention discloses a self-excited injection crystal oscillator, which consists of a starting circuit and a steady-state circuit. In the starting mode, a power supply is connected with the crystal oscillator through a switch to excite the quartz crystal so as to generate oscillation current. The comparator detects the zero crossing point of the oscillation current and the state of the switch is switched by the digital control module. The amplitude of the oscillation current gradually increases and serves as an injection signal of the crystal oscillator. After the crystal oscillator reaches a steady state, the amplifier provides energy to maintain a stable oscillation state. The crystal oscillator adopting the self-excitation injection technology can realize accurate same-frequency injection, shortens the starting time, does not need an oscillator injection or frequency calibration circuit and saves the power consumption.
Description
Technical Field
The invention belongs to the technical field of low-power consumption clocks, and particularly relates to a self-excited injection crystal oscillator.
Background
In recent years, rapid popularization of communication modes such as bluetooth, WIFI, GPS and the like has greatly promoted application of Ultra-Low Power (ULP) systems, such as internet of things, wireless sensor networks, energy collection systems and the like. And the ultra-low power consumption technology is very important for reducing the energy consumption of the system and prolonging the service life of the battery. The crystal oscillator provides reference frequency for modules such as a phase-locked loop, an analog-to-digital converter and the like in the system. But the starting time is long, so that the influence on the system power consumption is large. Therefore, it is very important to shorten the start-up time of the crystal oscillator.
The prior art includes increasing the negative resistance of the crystal oscillator and injecting an oscillation signal into the quartz crystal to speed up start-up. The increase of the negative resistance of the crystal oscillator is limited by the parallel capacitance in the quartz crystal, and the effect of accelerating the starting is very limited. The technology of accelerating the starting by injecting an oscillation signal into a quartz crystal is generally adopted at present. But this technique requires that the frequency error between the injected signal and the crystal oscillator be less than 0.5%. The use of calibration circuitry may improve injection frequency accuracy, but may increase power consumption; frequency calibration can be avoided by jitter injection and chirp injection, but both techniques are inefficient because of excessive loss due to large error between the injected partial energy and the target frequency.
Disclosure of Invention
The purpose of the invention is as follows: in order to solve the problems, the invention provides a self-excitation injection crystal oscillator, which shortens the starting time of the crystal oscillator by adopting a starting module of a self-excitation injection technology.
The technical scheme is as follows: in order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows: a self-excited injection crystal oscillator comprises a quartz crystal, a start circuit, a steady-state circuit, and a first load capacitor CLpA second load capacitor CLnFirst selection switch S00A second selection switch S01(ii) a X of quartz crystalpTerminating the first load capacitor CLpUpper plate of (2) and first selection switch S00The right end of (a); a first load capacitor CLpThe lower polar plate of the grounding device is grounded; x of quartz crystalnTerminating the second load capacitor CLnAnd a second selection switch S01The right end of (a); second load capacitance CLnThe lower polar plate of the grounding device is grounded; in the start mode, the first selection switch S00The P end of the starting circuit is connected; second selection switch S01The N end of the starting circuit is connected; in the steady-state mode, the first selection switch S00The P end of the steady-state circuit is connected; second selection switch S01And is connected with the N end of the steady-state circuit.
Further, the starting circuit comprises a comparator, a switch circuit and a digital control module; the negative input end of the first comparator A is connected with the power supply VDD and the first switch circuit S1At the left end of (1)The positive input end of a comparator A is connected with the first switch circuit S1P terminal of the start circuit and the third switch circuit S3The upper end of (a); the output end of the first comparator A is connected with the S of the digital control modulepA terminal; the negative input end of the second comparator B is connected with the power supply VDD and the second switch circuit S2The positive input end of the second comparator B is connected with the second switch circuit S2The left end of the starting circuit, the N end of the starting circuit and a fourth switching circuit S4The upper end of (a); the output end of the second comparator B is connected with the S of the digital control modulenAnd (4) an end.
Further, the output end SW of the digital control module is connected with the fourth switch circuit S4And a first switching circuit S1The control terminal of (1); output end SW of digital control modulenA third switch circuit S3And a second switching circuit S2The control terminal of (1).
Further, a third switch circuit S3The lower end of the upper end is grounded; fourth switching circuit S4The lower end of which is grounded.
Further, the digital control module controls the specific processes of switching on and off of the four switching circuits: s1And S4Closure, S2And S3Disconnected, P terminal passes through switch S1Connecting VDD, N terminal passing S4Grounding, and generating an oscillation signal after the crystal is excited; when the positive input end voltage of the comparator A exceeds the negative input end voltage, the digital control module switches the states of the four switches S2And S3Closure, S1And S4Disconnected, P terminal passes through switch S3Grounding, N terminal passing through S2Connecting with VDD; when the positive input end voltage of the comparator B exceeds the negative input end voltage, the digital control module switches the states of the four switches again.
Has the advantages that: the invention adopts the power supply and the switch circuit to excite the quartz crystal to generate the oscillation signal, and takes the oscillation signal as the injection signal of the crystal oscillator, and because the oscillation signal is generated by the crystal oscillator and almost has no deviation with the frequency of the crystal oscillator, the problem that the injection signal is difficult to have the same frequency with the crystal oscillator because of the injection of the external oscillator is avoided. The self-excitation injection technology not only realizes the purpose of accelerating the starting of the crystal oscillator, but also does not need an oscillator and frequency calibration, thereby saving the power consumption.
Drawings
FIG. 1 is a general block diagram of the self-injection crystal oscillator circuit of the present invention;
FIG. 2 is a block diagram of the start-up circuit of the self-injection crystal oscillator of the present invention;
fig. 3 is a graph of the oscillation current in start-up mode and steady-state mode.
Detailed Description
The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.
As shown in FIG. 1, the self-excited injection crystal oscillator of the present invention comprises a quartz crystal, a start-up circuit, a steady-state circuit, and a first load capacitor CLpA second load capacitor CLnFirst selection switch S00A second selection switch S01. Wherein, X of quartz crystalpTerminating the first load capacitor CLpUpper plate of (2) and first selection switch S00The right end of (a); a first load capacitor CLpThe lower plate of the anode is grounded. X of quartz crystalnTerminating the second load capacitor CLnAnd a second selection switch S01The right end of (a); second load capacitance CLnThe lower plate of the anode is grounded. In the start mode, the first selection switch S00The P end of the starting circuit is connected; second selection switch S01The N end of the starting circuit is connected; in the steady-state mode, the first selection switch S00The P end of the steady-state circuit is connected; second selection switch S01And is connected with the N end of the steady-state circuit.
As shown in fig. 2, the start-up circuit includes a comparator, a switching circuit, and a digital control module. Wherein the negative input terminal of the first comparator A is connected with the power supply VDD and the first switch circuit S1The positive input end of the first comparator A is connected with the first switch circuit S1P terminal of the start circuit and the third switch circuit S3The upper end of (a); the output end of the first comparator A is connected with the S of the digital control modulepAnd (4) an end.
The negative input end of the second comparator B is connected with the power supply VDD and the second switch circuitRoad S2The positive input end of the second comparator B is connected with the second switch circuit S2The left end of the starting circuit, the N end of the starting circuit and a fourth switching circuit S4The upper end of (a); the output end of the second comparator B is connected with the S of the digital control modulenAnd (4) an end.
S of the digital control module of the inventionpThe S end of the digital control module is connected with the output end of the first comparator AnThe output end of the second comparator B is connected with the end; the output end SW of the digital control module is connected with the fourth switch circuit S4And a first switching circuit S1The control terminal of (1); output end SW of digital control modulenA third switch circuit S3And a second switching circuit S2The control terminal of (1).
The digital control module controls the specific processes of switching on and off of the four switching circuits: first, S1And S4Closure, S2And S3Disconnected, P terminal passes through switch S1Connecting VDD, N terminal passing S4Grounded, and the crystal generates an oscillating signal after being excited. When the positive input end voltage of the comparator A exceeds the negative input end voltage, the digital control module switches the states of the four switches, namely S2And S3Closure, S1And S4And (5) disconnecting. At this time, the P terminal passes through the switch S3Grounding, N terminal passing through S2And then is connected with VDD. When the positive input end voltage of the comparator B exceeds the negative input end voltage, the digital control module switches the states of the four switches again, namely S1And S4Closure, S2And S3And (4) disconnecting, and circulating to work.
The switching circuit of the present invention includes a first switching circuit S1A second switch circuit S2And a third switch circuit S3A fourth switching circuit S4. The switching circuit may be a MOSFET switching circuit structure.
Wherein the first switch circuit S1The left end of the first comparator A is connected with the negative input end of the first comparator A and a power supply VDD; first switch circuit S1The right end is connected with the P end of the starting circuit and the third switch circuit S3The upper end of (a); third switch circuit S3The lower end of which is grounded. Second switch circuit S2Right end second ratioThe negative input end of the comparator B is connected with a power supply VDD; second switch circuit S2The left end is connected with the N end of the starting circuit and the fourth switching circuit S4The upper end of (a); fourth switching circuit S4The lower end of which is grounded.
The invention relates to a self-excited injection crystal oscillator, which consists of a starting circuit and a steady-state circuit. In the starting mode, a power supply is connected with the crystal oscillator through a switch to excite the quartz crystal so as to generate oscillation current. The comparator detects the zero crossing point of the oscillation current and the state of the switch is switched by the digital control module. The amplitude of the oscillation current gradually increases and serves as an injection signal of the crystal oscillator. After the crystal oscillator reaches a steady state, the amplifier provides energy to maintain a stable oscillation state. The oscillating current conditions in start-up mode and steady-state mode are shown in fig. 3. The crystal oscillator adopting the self-excitation injection technology can realize accurate same-frequency injection, shortens the starting time, does not need an oscillator injection or frequency calibration circuit and saves the power consumption.
Claims (5)
1. A self-excited injection crystal oscillator comprises a quartz crystal, a start-up circuit, a steady-state circuit, and a first load capacitor (C)Lp) A second load capacitor (C)Ln) First selection switch (S)00) And a second selection switch (S)01)；
X of quartz crystalpTerminating the first load capacitance (C)Lp) And a first selection switch (S)00) The right end of (a); a first load capacitance (C)Lp) The lower polar plate of the grounding device is grounded;
x of quartz crystalnTerminating the second load capacitance (C)Ln) And a second selection switch (S)01) The right end of (a); a second load capacitance (C)Ln) The lower polar plate of the grounding device is grounded;
in the start mode, the first selection switch (S)00) The P end of the starting circuit is connected; second selection switch (S)01) The N end of the starting circuit is connected;
in steady-state mode, the first selection switch (S)00) The P end of the steady-state circuit is connected; second selection switch (S)01) And is connected with the N end of the steady-state circuit.
2. A self-excited injection crystal oscillator according to claim 1, wherein the start-up circuit includes a comparator, a switching circuit and a digital control module;
the negative input terminal of the first comparator (A) is connected to the power supply (VDD) and the first switch circuit (S)1) The positive input of the first comparator (A) is connected with the first switch circuit (S)1) P terminal of the start circuit, and the third switch circuit (S)3) The upper end of (a); the output end of the first comparator (A) is connected with the S of the digital control modulepA terminal;
the negative input terminal of the second comparator (B) is connected to the power supply (VDD) and the second switch circuit (S)2) A positive input of the second comparator (B) is connected with the second switch circuit (S)2) Left end of the start circuit, N end of the start circuit and a fourth switch circuit (S)4) The upper end of (a); the output end of the second comparator (B) is connected with the S of the digital control modulenAnd (4) an end.
3. Self-excited injection crystal oscillator according to claim 2, characterized in that the output SW of the digital control module is connected to a fourth switching circuit (S)4) And a first switch circuit (S)1) The control terminal of (1); output end SW of digital control modulenIs connected with a third switch circuit (S)3) And a second switching circuit (S)2) The control terminal of (1).
4. Self-excited injection crystal oscillator according to claim 2, characterized in that the third switching circuit (S)3) The lower end of the upper end is grounded; a fourth switching circuit (S)4) The lower end of which is grounded.
5. The self-excited injection crystal oscillator of claim 2, wherein the digital control module controls the specific processes of turning on and off four switching circuits: s1And S4Closure, S2And S3Disconnected, P terminal passes through switch S1Connecting VDD, N terminal passing S4Grounding, and generating an oscillation signal after the crystal is excited; when the positive input end of the comparator A is electrically connectedAfter the voltage exceeds the voltage of the negative input terminal, the digital control module switches the states of the four switches, S2And S3Closure, S1And S4Disconnected, P terminal passes through switch S3Grounding, N terminal passing through S2Connecting with VDD; when the positive input end voltage of the comparator B exceeds the negative input end voltage, the digital control module switches the states of the four switches again.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010933422.XA CN112217476A (en) | 2020-09-08 | 2020-09-08 | Self-excited injection crystal oscillator |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010933422.XA CN112217476A (en) | 2020-09-08 | 2020-09-08 | Self-excited injection crystal oscillator |
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| CN112217476A true CN112217476A (en) | 2021-01-12 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024103589A1 (en) * | 2022-11-14 | 2024-05-23 | 南京邮电大学 | High-frequency crystal oscillator based on automatic phase error correction |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103066942A (en) * | 2012-12-20 | 2013-04-24 | 无锡中科微电子工业技术研究院有限责任公司 | Quick-start crystal oscillator circuit with ultra-low power consumption |
| CN107294506A (en) * | 2016-03-30 | 2017-10-24 | 中芯国际集成电路制造(上海)有限公司 | Crystal-oscillator circuit |
| CN109120231A (en) * | 2017-06-26 | 2019-01-01 | 硕呈科技股份有限公司 | The single contact crystal vibration device and operating method of fast start-up |
| US20200244220A1 (en) * | 2019-01-24 | 2020-07-30 | Nxp B.V. | Crystal oscillator circuit and method of operation |
-
2020
- 2020-09-08 CN CN202010933422.XA patent/CN112217476A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103066942A (en) * | 2012-12-20 | 2013-04-24 | 无锡中科微电子工业技术研究院有限责任公司 | Quick-start crystal oscillator circuit with ultra-low power consumption |
| CN107294506A (en) * | 2016-03-30 | 2017-10-24 | 中芯国际集成电路制造(上海)有限公司 | Crystal-oscillator circuit |
| CN109120231A (en) * | 2017-06-26 | 2019-01-01 | 硕呈科技股份有限公司 | The single contact crystal vibration device and operating method of fast start-up |
| US20200244220A1 (en) * | 2019-01-24 | 2020-07-30 | Nxp B.V. | Crystal oscillator circuit and method of operation |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024103589A1 (en) * | 2022-11-14 | 2024-05-23 | 南京邮电大学 | High-frequency crystal oscillator based on automatic phase error correction |
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