CN102545779B - Crystal-oscillation-free clock circuit - Google Patents
Crystal-oscillation-free clock circuit Download PDFInfo
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- CN102545779B CN102545779B CN201210036260.5A CN201210036260A CN102545779B CN 102545779 B CN102545779 B CN 102545779B CN 201210036260 A CN201210036260 A CN 201210036260A CN 102545779 B CN102545779 B CN 102545779B
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Abstract
The invention relates to a clock circuit, and provides a crystal-oscillation-free clock circuit which is capable of effectively improving the temperature stability of a clock signal generated by the clock circuit and making the frequency of the clock signal generated by the clock circuit not changed along with the change of outside temperature, and has an extremely low temperature drift coefficient. The crystal-oscillation-free clock circuit is provided with a linear voltage stabilization module, a high-order temperature compensation module and an annular oscillation module, wherein the linear voltage stabilization module is externally connected with power supply voltage; the two same output voltage output end of the linear voltage stabilization module are connected with the input end of the high-order temperature compensation module and the input end of the annular oscillation module respectively; the reference output voltage of the linear voltage stabilization module is connected with the input end of the high-order temperature compensation module; the output end of the high-order temperature compensation module is connected with the input end of the annular oscillation module; and the annular oscillation module outputs a final clock signal.
Description
Technical field
The present invention relates to a kind of clock circuit, especially relate to and a kind ofly without crystal oscillator, can float clock generation circuit by single chip integrated High Precision Low Temperature.
Background technology
In digital system, the quality of clock source has directly determined whether stablizing of this systematic function.Conventionally digital system utilizes the outer quartz oscillator of sheet to obtain clock source signals, quartz crystal oscillator has superior voltage and temperature characterisitic, can stably work, but be difficult to be integrated into chip internal, and increased device cost, hindered the Highgrade integration of chip.Utilize the clock oscillator that the CMOS technique of standard realizes in sheet to replace the crystal oscillator outside sheet, for the cost that reduces system, improve the integrated level of system by helpful.
In standard CMOS process, realizing high precision clock, to produce problem that main circuit will face be that clock frequency can variation with temperature and change, it is the stability that how to guarantee clock frequency that the existing sheet internal clock of historical facts or anecdotes produces the challenge that main circuit will face, and makes not variation with temperature and changing of frequency of oscillation.
Krishnakumar Sundaresan, (the Krishnakumar Sundaresan such as Phillip E.Allen, Phillip E.Allen etal.Process and Temperature Compensation in a 7-MHz CMOS Clock Oscillator.IEEE JOURNALOF SOLID-STATE CIRCUITS, 2006,41 (2): 433-442) utilize the temperature characterisitic of the forward conduction voltage of bipolar transistor to produce temperature-compensated voltage, thereby guarantee the stability of frequency of oscillation.
(the Yu Xiaofan such as Yu Xiaofan, woods divides equally. a kind of on chip clock oscillator with temperature and technological compensa tion. and microelectronics and computer, 2009,26 (1): 16-20) utilize the circuit structure of similar band-gap reference to produce temperature-compensated voltage, thereby guarantee the stability of frequency of oscillation.
Chao-Fang Tsai, (the Chao-Fang Tsai such as Wan-Jing Li, the .On-Chip ReferenceOscillators with Process such as Wan-Jing Li, Supply Voltage and Temperature Compensation.International Symposiumon Next-Generation Electronics (ISNE), 2010,108-111) utilize the temperature characterisitic of the NMOS pipe gate source voltage of sub-threshold region to produce temperature-compensated voltage, thereby guarantee the stability of frequency of oscillation.
But the compensation thinking of mentioning in above-mentioned document is all the impact that the first-order linear relation of forward conduction voltage based on PN junction and temperature comes compensation temperature to produce, and its compensation effect is limited.
Summary of the invention
The object of the present invention is to provide a kind of temperature stability that can effectively improve the clock signal that clock circuit produces, the clock signal frequency that clock circuit produces is not changed with the variation of ambient temperature, have very low temperature float coefficient without crystal oscillation clock circuit.
Technical scheme of the present invention is to utilize the I-V characteristic curve of metal-oxide-semiconductor, adopts the temperature-compensated voltage of the principle generation high-order of stack, acts on the ring oscillation module in clock circuit.
The present invention is provided with linear voltage stabilization module, high-order temperature compensated module and ring oscillation module;
The external supply power voltage of described linear voltage regulator module, two same output voltage outputs of linear voltage regulator module connect respectively the input of high-order temperature compensated module and the input of ring oscillation module, the benchmark output voltage of linear voltage regulator module connects the input of high-order temperature compensated module, the input of the output T-Ring shape oscillation module of high-order temperature compensated module, ring oscillator module is exported final clock signal.
Described linear voltage stabilization module can be provided with band-gap reference circuit, error amplifier, adjustment pipe and feedback resistance, described ring oscillation module can be provided with at least one grade of difference delay unit and both-end turns single-end circuit, the input of the high-order temperature compensated module of band gap voltage output termination of described band-gap reference circuit and the input of error amplifier, another input termination feedback resistance of error amplifier, the output termination adjustment pipe of error amplifier, a comparison signal input of the feedback voltage output termination error amplifier of feedback resistance, the band gap voltage output of band-gap reference circuit connects respectively another comparison signal input of error amplifier and the input of high-order temperature compensated module, the adjustment Voltage-output termination of error amplifier is adjusted the grid (control end) of pipe, the difference delay unit input of high-order temperature compensated module temperature-compensated voltage output T-Ring shape oscillation module, the output termination both-end of difference delay unit turns the input of single-end circuit, both-end turns the clock signal output terminal clock signal of single-end circuit.
Described high-order temperature compensated module can be provided with at least 1 basic element circuit and supercircuit, and its input/output port comprises: the bandgap voltage reference that the stable supply voltage that linear voltage stabilization module provides, linear voltage stabilization module provide, earth terminal, high-order temperature compensated voltage.The output of described at least 1 basic element circuit is by the electric current of the combination results resistance of flowing through, produce the required voltage waveform of supercircuit, supercircuit is accepted the voltage waveform that elementary cell produces, the mode superposeing by voltage, by at least two, for the voltage superposeing, do overlap-add procedure, produce final temperature-compensated voltage.
The present invention will treat that stable voltage transitions becomes stable supply power voltage, is high-order temperature compensated module and ring oscillation module for power supply, and stable supply power voltage can be so that the frequency of oscillation that ring oscillation module produces not be affected by the variation of voltage.The required bandgap voltage reference of high-order temperature compensated module is also provided by this linear voltage stabilization module.
High-order temperature compensated module automatically adjusts according to the variation of ambient temperature the temperature-compensated voltage that offers ring oscillation module, makes ring oscillation module keep fixing frequency constant.This high-order temperature compensated module can produce the temperature-compensated voltage of high-order, also with the rising of temperature, function of temperature compensation control voltage is not only linearity or very approaching decline linearly (or rising), but curvilinear style ground declines (or rising), and the voltage swing of this point of inflexion on a curve number, position and curve all can regulate by the parameter in high-order temperature compensated module.By high-order compensation, the clock oscillation signal that ring oscillation module produces will have better temperature stability.
Ring oscillation module produces clock oscillation signal by the mutual cascade of difference delay unit, and the temperature-compensated voltage that utilizes high-order temperature compensated module to provide is used as the control voltage of ring oscillation module, thereby guarantee not variation with temperature and changing of clock oscillation signal frequency.
The present invention can be used for producing clock signal accurately, is the source of digital system clock signal in integrated circuit.This clock circuit can be produced by monolithic, is also independent flow, makes the clock chip of high stable, also can be integrated into above SOC (system on a chip) SoC or application-specific integrated circuit ASIC etc., as the clock of chip, supplies with source.
Accompanying drawing explanation
Fig. 1 is the structure composition frame chart of the embodiment of the present invention.
Fig. 2 is the linear voltage stabilization modular circuit schematic diagram of the embodiment of the present invention.
Fig. 3 is the difference time-delay unit circuit schematic diagram of the embodiment of the present invention.
Fig. 4 is that the both-end of the embodiment of the present invention turns single-end circuit schematic diagram.
Fig. 5 is the ring oscillation modular circuit schematic diagram of the embodiment of the present invention.
Fig. 6 is the circuit theory diagrams of elementary cell in the high-order temperature compensated module of the embodiment of the present invention.
Fig. 7 is the I-V characteristic curve of Fig. 6.
Fig. 8 is the circuit theory diagrams after three elementary cells combinations in the high-order temperature compensated module of the embodiment of the present invention.
Fig. 9 is the V of the embodiment of the present invention
tvoltage generation circuit schematic diagram.
Figure 10 is the bleeder circuit schematic diagram of the embodiment of the present invention.
Figure 11 is the supercircuit schematic diagram of the embodiment of the present invention.
Embodiment
Referring to Fig. 1～5, the embodiment of the present invention is provided with linear voltage stabilization module 1, high-order temperature compensated module 2 and ring oscillation module 3;
The external supply power voltage of described linear voltage regulator module, two same output voltage outputs of linear voltage regulator module connect respectively the input of high-order temperature compensated module 2 and the input of ring oscillation module 3, the benchmark output voltage of linear voltage regulator module 1 connects the input of high-order temperature compensated module 2, the input of the output T-Ring shape oscillation module 3 of high-order temperature compensated module 2, ring oscillator module is exported final clock signal.
Referring to Fig. 2, described linear voltage stabilization module 1 can be provided with band-gap reference circuit 11, error amplifier (seeing the U1 in Fig. 2), adjust pipe (seeing the Q1 in Fig. 2) and feedback resistance (seeing the R in Fig. 2).
Fig. 3 is the difference delay unit of ring oscillation module, and Fig. 4 is that both-end turns single-end circuit schematic diagram, and three difference delay units and both-end turn ring oscillation modular circuit schematic diagram that single-end circuit forms as shown in Figure 5.
Described ring oscillation module 3 can be provided with at least one grade of difference delay unit 31 and both-end turns single-end circuit 32; The band gap voltage V of described band-gap reference circuit 11
bEFthe input of the high-order temperature compensated module 2 of output termination and the input of error amplifier, another input termination feedback resistance of error amplifier, the output termination adjustment pipe of error amplifier, a comparison signal input of the feedback voltage output termination error amplifier of feedback resistance, the band gap voltage V of band-gap reference circuit 11
bEFoutput connects respectively another comparison signal input of error amplifier and the input of high-order temperature compensated module 2, and the adjustment Voltage-output termination of error amplifier is adjusted the grid (control end) of pipe, high-order temperature compensated module 2 temperature-compensated voltage V
cTRLdifference delay unit 31 inputs of output T-Ring shape oscillation module 3, the output termination both-end of difference delay unit 31 turns the input of single-end circuit 32, and both-end turns the clock signal output terminal clock signal of single-end circuit 32.The voltage that the feedback voltage that error amplifier provides feedback resistance and band-gap reference produce compares and exports adjustment voltage, adjusts voltage and by control, adjusts the grid of pipe, will treat stable voltage V
bATconvert stable supply voltage V to
dD, the band gap voltage V that band-gap reference produces
rEFpull out for high-order temperature compensated module.
By emulation, can obtain, the in the situation that of extraneous variation of ambient temperature, make the frequency of oscillation of this ring oscillator remain unchanged, so ring oscillator for control frequency control voltage V
cTRLat least to represent with the equation containing cube item with the relation of temperature T, shape as:
V
CTTRL＝α·T+β·T
2+γ·T
3(1)
Wherein, the factor alpha of first power item is maximum, and the factor beta of quadratic component is taken second place, and the coefficient gamma of cube item is minimum.
Referring to 6～11, described high-order temperature compensated module 2 can be provided with at least 1 basic element circuit and supercircuit, and its input/output port comprises: the bandgap voltage reference that the stable supply voltage that linear voltage stabilization module provides, linear voltage stabilization module provide, earth terminal, high-order temperature compensated voltage.The output of described at least 1 basic element circuit is by the electric current of the combination results resistance of flowing through, produce the required voltage waveform of supercircuit, supercircuit is accepted the voltage waveform that elementary cell produces, the mode superposeing by voltage, by at least two, for the voltage superposeing, do overlap-add procedure, produce final temperature-compensated voltage.
The basic element circuit schematic diagram of high-order temperature compensated module as shown in Figure 6, reference voltage V
rEFXfixing, work as V
twhile increasing since 0, the current Ib by resistance R b and the electric current I a by resistance R a are as shown in Figure 7.Choose different V
rEFX, at a fixing V
tin scope, the current curve section Ia obtaining or Ib will be different.In Fig. 8, by three this elementary cell combinations, select suitable reference voltage V
rEFL< V
rEFM< V
rEFH, V
tfor the voltage declining with temperature linearity, wherein V
tby bipolar transistor base-emitter voltage as shown in Figure 9, produced reference voltage V
rEFL, V
rEFM, V
rEFHthe bandgap voltage reference being provided by linear voltage stabilization module produces by the bleeder circuit shown in Figure 10 (A2 in Figure 10 is operational amplifier), so along with the rising of temperature, I1 can obtain the right half part of current Ib in Fig. 7, I2 can obtain the mid portion of electric current I a in Fig. 7, I3 can obtain the left-half of current Ib in Fig. 7, I1, I2, I3 is by resistance R c2, the voltage V of generation
oUTbe the voltage of the middle quadratic component of formula (1) and cube item.
The above-mentioned circuit being comprised of elementary cell is the voltage of first power item in production (1) not, thus also need a circuit that produces first power item voltage, and superimposed with above-mentioned quadratic component and cube item voltage.As shown in Figure 11 supercircuit, the Vout in figure is provided by the circuit of Fig. 8, and this voltage is by operational amplifier A 1, metal-oxide-semiconductor M
ts1 converts electric current to resistance R, then is mirrored to output by current-mirror structure, by resistance R s2, superimposed with first power item voltage (Q2 produces by bipolar transistor), finally generates temperature-compensated voltage V
cTRL.
Claims (1)
1. without a crystal oscillation clock circuit, it is characterized in that being provided with linear voltage stabilization module, high-order temperature compensated module and ring oscillation module;
The external supply power voltage of described linear voltage stabilization module, two same output voltage outputs of linear voltage stabilization module connect respectively the input of high-order temperature compensated module and the input of ring oscillation module, the benchmark output voltage of linear voltage stabilization module connects the input of high-order temperature compensated module, the input of the output T-Ring shape oscillation module of high-order temperature compensated module, ring oscillation module is exported final clock signal;
Described linear voltage stabilization module is provided with band-gap reference circuit, error amplifier, adjustment pipe and feedback resistance, described ring oscillation module is provided with at least difference delay unit and the both-end of one-level ring oscillation module and turns single-end circuit, the input of the high-order temperature compensated module of band gap voltage output termination of described band-gap reference circuit and the input of error amplifier, another input termination feedback resistance of error amplifier, the output termination adjustment pipe of error amplifier, a comparison signal input of the feedback voltage output termination error amplifier of feedback resistance, the band gap voltage output of band-gap reference circuit connects respectively another comparison signal input of error amplifier and the input of high-order temperature compensated module, the adjustment Voltage-output termination of error amplifier is adjusted the grid of pipe, the difference delay unit input of high-order temperature compensated module temperature-compensated voltage output T-Ring shape oscillation module, the output termination both-end of the difference delay unit of ring oscillation module turns the input of single-end circuit, both-end turns the clock signal output terminal clock signal of single-end circuit,
The grid of the one PMOS pipe of described difference delay unit is connected and is connected to negative output voltage V with drain electrode
out-, source electrode meets supply voltage V
dD, the source electrode of the 2nd PMOS pipe is connected with the source electrode of a PMOS pipe, and grid connects controls voltage V
cTRL, drain electrode is connected with the drain electrode of a PMOS pipe, and the grid of the 3rd NMOS pipe meets positive input voltage V
in+, drain electrode is connected with a PMOS pipe drain electrode, and the 4th PMOS pipe source electrode meets supply voltage V
dD, grid is connected to together with the second gate pmos utmost point controls voltage V
cTRL, drain electrode connects positive output voltage V
out+,the source electrode of the 5th PMOS pipe meets supply voltage V
dD, drain and gate is received the drain electrode of the 4th PMOS pipe together, and the drain electrode of the 6th NMOS pipe connects the drain electrode of the 4th PMOS pipe, and grid meets negative input voltage V
in-, source electrode connects the 3rd NMOS pipe source electrode, the source electrode of current source one termination the 3rd NMOS pipe and the source electrode of the 6th NMOS pipe, the other end ground connection of current source;
Described high-order temperature compensated module is provided with at least 1 basic element circuit and supercircuit, its input/output port comprises: the stable supply voltage that linear voltage stabilization module provides, the bandgap voltage reference that linear voltage stabilization module provides, earth terminal, high-order temperature compensated voltage, the output of described at least 1 basic element circuit is by the electric current of the combination results resistance of flowing through, produce the required voltage waveform of supercircuit, supercircuit is accepted the voltage waveform that elementary cell produces, the mode superposeing by voltage, by at least two, for the voltage superposeing, do overlap-add procedure, produce final temperature-compensated voltage, wherein said basic element circuit by the first branch road PMOS manage, the second branch road PMOS pipe, the first branch road resistance, the second branch road resistance and current source form, the source electrode of the first branch road PMOS pipe connects current source one end, drain electrode connects first branch road resistance one end, and grid connects reference voltage, the other end ground connection of the first branch road resistance, the source electrode of the second branch road PMOS pipe connects the first branch road PMOS pipe source electrode, and grid connects the voltage changing with temperature linearity, and drain electrode connects second branch road resistance one end, the other end ground connection of the second branch road resistance, the source electrode of current source one end and the first branch road PMOS pipe, the source electrode of the second branch road PMOS pipe are connected, another termination power of current source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210036260.5A CN102545779B (en) | 2012-02-16 | 2012-02-16 | Crystal-oscillation-free clock circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210036260.5A CN102545779B (en) | 2012-02-16 | 2012-02-16 | Crystal-oscillation-free clock circuit |
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| Publication Number | Publication Date |
|---|---|
| CN102545779A CN102545779A (en) | 2012-07-04 |
| CN102545779B true CN102545779B (en) | 2014-10-08 |
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| CN201210036260.5A Expired - Fee Related CN102545779B (en) | 2012-02-16 | 2012-02-16 | Crystal-oscillation-free clock circuit |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104135277B (en) * | 2014-07-25 | 2017-06-13 | 深圳大学 | Reference clock produces circuit and method on a kind of piece |
| CN106209025B (en) * | 2016-08-26 | 2023-05-23 | 哈尔滨工业大学（威海） | Ring oscillator with process and temperature compensation |
| CN116054782A (en) * | 2018-06-25 | 2023-05-02 | 瑞昱半导体股份有限公司 | Clock adjusting circuit and clock adjusting method |
| CN110018344A (en) * | 2019-02-21 | 2019-07-16 | 国网山东省电力公司临沂供电公司 | The electric energy metering device for having identification power load function |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1261993A (en) * | 1997-07-11 | 2000-08-02 | 松下电器产业株式会社 | Function generation circuit, crystal oscillation device,and method of adjusting the oscillation device |
| CN101557210A (en) * | 2009-03-05 | 2009-10-14 | 西安民展微电子有限公司 | Circuit for generating sawtooth waves and clock signals |
| CN102064801A (en) * | 2010-11-08 | 2011-05-18 | 中国兵器工业集团第二一四研究所苏州研发中心 | All-silicon clock generator realized on basis of complementary metal oxide semiconductor (CMOS) process |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100446305B1 (en) * | 2002-08-20 | 2004-09-01 | 삼성전자주식회사 | Power supply voltage-, temperature-independent R-C oscillator using controllable Schmitt trigger |
-
2012
- 2012-02-16 CN CN201210036260.5A patent/CN102545779B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1261993A (en) * | 1997-07-11 | 2000-08-02 | 松下电器产业株式会社 | Function generation circuit, crystal oscillation device,and method of adjusting the oscillation device |
| CN101557210A (en) * | 2009-03-05 | 2009-10-14 | 西安民展微电子有限公司 | Circuit for generating sawtooth waves and clock signals |
| CN102064801A (en) * | 2010-11-08 | 2011-05-18 | 中国兵器工业集团第二一四研究所苏州研发中心 | All-silicon clock generator realized on basis of complementary metal oxide semiconductor (CMOS) process |
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| CN102545779A (en) | 2012-07-04 |
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Granted publication date: 20141008 Termination date: 20200216 |