CN107317567A - The RC oscillating circuits of low-temperature coefficient output frequency - Google Patents
The RC oscillating circuits of low-temperature coefficient output frequency Download PDFInfo
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- CN107317567A CN107317567A CN201610264112.7A CN201610264112A CN107317567A CN 107317567 A CN107317567 A CN 107317567A CN 201610264112 A CN201610264112 A CN 201610264112A CN 107317567 A CN107317567 A CN 107317567A
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- way switch
- current source
- output frequency
- temperature coefficient
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/01—Details
- H03K3/011—Modifications of generator to compensate for variations in physical values, e.g. voltage, 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
- H03B5/20—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
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- Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
Abstract
The invention discloses a kind of RC oscillating circuits of low-temperature coefficient output frequency, including the first current source, second current source, 3rd current source, the FET being connected with first current source, the adjustable resistance being connected with the FET, the resistance being connected with the adjustable resistance, the first two-way switch being connected with the FET and the adjustable resistance, the comparator being connected with first two-way switch, it is connected to the second two-way switch between second current source and the 3rd current source, the electric capacity and clock signal output terminal being connected with second two-way switch, the clock signal output terminal and first two-way switch, the comparator, second two-way switch and the electric capacity are connected jointly, and produce a temperature-independent clock signal of output frequency.The output frequency for the clock signal that the present invention is produced is accurate and does not vary with temperature and changes.
Description
Technical field
The present invention relates to integrated circuit fields, more particularly to a kind of RC oscillating circuits of low-temperature coefficient output frequency.
Background technology
In integrated circuit fields, generally require to provide a frequency very precisely and temperature coefficient very low clock signal is to circuit system
In, the clock signal is now produced usually using RC oscillating circuits.
The output frequency for the clock signal that existing RC oscillating circuits are produced often changes with the change of temperature, it is difficult to provide one
Individual frequency is very precisely and temperature coefficient very low clock signal is to circuit system, i.e., the clock letter that existing RC oscillating circuits are produced
Number the temperature-compensating of output frequency be always problem.
The content of the invention
A frequency very accurate and temperature coefficient can be produced it is an object of the invention to overcome the deficiencies of the prior art and provide one kind
The RC oscillating circuits of the low-temperature coefficient output frequency of very low clock signal.
The purpose of the present invention is achieved through the following technical solutions：A kind of RC oscillating circuits of low-temperature coefficient output frequency,
Including the first current source, the second current source, the 3rd current source, the FET being connected with first current source, with the field
The connected adjustable resistance of effect pipe, the resistance being connected with the adjustable resistance, it is connected with the FET and the adjustable resistance
The first two-way switch, be connected with first two-way switch comparator, be connected to second current source with the described 3rd electricity
The second two-way switch between stream source, the electric capacity and clock signal output terminal being connected with second two-way switch, the clock letter
Number output end is connected jointly with first two-way switch, the comparator, second two-way switch and the electric capacity, and is produced
A raw temperature-independent clock signal of output frequency.
The size of current that second current source and the 3rd current source are produced is equal.
One end connection power end of first current source, the other end connects one end of the FET, the FET
The other end connects one end of the adjustable resistance, and the other end of the adjustable resistance connects one end of the resistance, the resistance
The other end is grounded.
One connection end of first two-way switch is connected at the tie point of first current source and the FET, described
Another connection end of first two-way switch is connected at the tie point of the adjustable resistance and the resistance, first two-way switch
Control end be connected with the positive input of the comparator.
The inverting input of the comparator is connected with the control end of second two-way switch and one end of the electric capacity, the ratio
When the control end of output end, the control end of first two-way switch and second two-way switch compared with device is commonly connected to described
Clock signal output part.
One end connection power end of second current source, the other end is connected with a connection end of second two-way switch, described
Another connection end of second two-way switch is connected with one end of the 3rd current source, the other end of the 3rd current source with it is described
The other end ground connection of electric capacity.
The beneficial effects of the invention are as follows：The output frequency for the clock signal that RC oscillating circuits are produced is accurate, does not vary with temperature and becomes
Change and temperature coefficient is very low.
Brief description of the drawings
Fig. 1 is the circuit diagram of the RC oscillating circuits of low-temperature coefficient output frequency of the present invention；
Fig. 2 is the waveform diagram of the RC oscillating circuits of low-temperature coefficient output frequency of the present invention.
Embodiment
Technical scheme is described in further detail below in conjunction with the accompanying drawings, but protection scope of the present invention is not limited to following institute
State.
As shown in figure 1, circuit diagrams of the Fig. 1 for the RC oscillating circuits of low-temperature coefficient output frequency of the present invention, it includes first
Current source I1, the second current source I2, the 3rd current source I3, with the first current source I1 FET M0 being connected and field-effect
Connected pipe M0 adjustable resistance R1, the resistance R0 being connected with adjustable resistance R1, the first two-way switch K1, with it is first two-way
Switch the connected comparator COM1 of K1, the second two-way switch being connected between the second current source I2 and the 3rd current source I3
K2, with the second two-way switch K2 electric capacity C0 being connected and clock signal output terminal CLK.Wherein, the second current source I2 and
The size of current that three current source I3 are produced is equal, is I0.
First current source I1 one end connection power end VDD, other end connection FET M0 one end, the voltage of tie point
For VH；FET M0 other end connection adjustable resistance R1 one end, adjustable resistance R1 other end connection resistance R0
One end, the voltage of tie point is VL, resistance R0 other end ground connection.A first two-way switch K1 connection end 1 is connected
To the first current source I1 and FET M0 tie point, the first two-way switch K1 another connection end 0 is connected to adjustable
At resistance R1 and resistance R0 tie point, the first two-way switch K1 control end T1 and comparator COM1 positive input
End is connected, and the voltage of tie point is VTH；The control end T1 of comparator COM1 inverting input and the second two-way switch K2
And electric capacity C0 one end is connected, the voltage of tie point is VC；Comparator COM1 output end, the first two-way switch K1
Control end T1, the second two-way switch K2 control end T1 are commonly connected to clock signal output terminal CLK, and comparator COM1
Output end produce voltage be VS.Second current source I2 one end connection power end VDD, the other end and the second two-way switch
A K2 connection end 1 is connected, and the second two-way switch K2 another connection end 0 is connected with the 3rd current source I3 one end, and the 3rd
The current source I3 other end is grounded with the electric capacity C0 other end.
Wherein, in other embodiments, FET M0 can realize the component of identical function for other structures, and
Not limited to this；For example, triode.
Please refer to Fig. 2, Fig. 2 is the waveform diagram of the RC oscillating circuits of low-temperature coefficient output frequency of the present invention.This hair
The operation principle of the RC oscillating circuits of bright low-temperature coefficient output frequency is as described below：
When scene effect pipe M0 is not accessed：Work as VCLess than VTHWhen, VSFor high level voltage, the first two-way switch K1's
Connection end 1 is connected, VTH=VH；Second two-way switch K2 connection end 1 is connected, electric current I0 injection electric capacity C0, VCWith
The injection of electric current and increase；Work as VCMore than VTHWhen, VSFor low level voltage, the first two-way switch K1 connection end 0 is connected,
VTH=VL, the second two-way switch K2 connection end 0 connected, and the electric charge on electric capacity C0 is declined with I0 speed, until VC
Drop to below VTH, VS is turned to 1, continue to restart.Waveform is as shown in Figure 2.
Wherein, Δ V=VH-VL；
Output frequency
It can thus be seen that RC oscillating circuits produce clock signal output frequency it is unrelated with electric current I0 sizes, with it is adjustable
Resistance R1 is relevant with electric capacity C0 product.
In integrated circuits, adjustable resistance R1 can change with temperature change, and electric capacity C0 can also change with temperature change,
It is as follows that it changes formula：
C0=C00×(1+CTC1×PT)；
Wherein, R10The resistance for being adjustable resistance R1 at 25 DEG C；C00The capacitance for being electric capacity C0 at 25 DEG C；RTC1、RTC2Point
Not Wei adjustable resistance R1 single order, second-order temperature coefficient；CTC1For electric capacity C0 single order temperature coefficient；PT=T-25, i.e.,
Temperature T and the difference of room temperature (25 DEG C) on piece.
The output frequency variation with temperature of clock signal that RC oscillating circuits are produced is：
Ignore high-order term and influence less item, can obtain：
Generally, RTC1For negative temperature coefficient, CTC1For positive temperature coefficient, RTC2For positive temperature coefficient, in above formula, RTC1
Account for main function, therefore output frequency FrcRise with the rising of temperature.
After scene effect pipe M0 accesses：
Wherein, FET M0 resistance temperature coefficient is positive temperature coefficient, it is assumed that it varies with temperature formula and is：
RM0=RM0×(1+RMTC1×PT)；
Wherein, RM0The resistance for being FET M0 at 25 DEG C；RMTC1For FET M0 single order temperature coefficient.
Then the output frequency for the clock signal that RC oscillating circuits are produced is：
Ignore high-order term and influence less item, can obtain：
The positive temperature coefficient of Section 2 can preferably offset the negative temperature coefficient of Section 1 in the formula denominator so that FrcNot with temperature
Change and change.
In addition, in the present invention it is possible to by adjusting adjustable resistance R1 size, obtain a frequency very accurately, temperature system
Count very low clock signal.
The RC oscillating circuits of low-temperature coefficient output frequency of the present invention can produce an output frequency very accurate and temperature coefficient very
Low clock signal so that the output frequency of clock signal will not change with the change of temperature.
In summary, the RC oscillating circuits of low-temperature coefficient output frequency of the present invention have the characteristics that：The clock signal of generation
Output frequency precisely, do not vary with temperature and change and temperature coefficient is very low.
Claims (6)
1. a kind of RC oscillating circuits of low-temperature coefficient output frequency, it is characterised in that：The low-temperature coefficient output frequency
RC oscillating circuits include the first current source, the second current source, the 3rd current source, the FET being connected with first current source,
The adjustable resistance that is connected with the FET, the resistance being connected with the adjustable resistance, with the FET and described adjustable
The first connected two-way switch of resistance, the comparator being connected with first two-way switch, it is connected to second current source and institute
State the second two-way switch between the 3rd current source, the electric capacity and clock signal output terminal that are connected with second two-way switch, institute
Clock signal output terminal is stated with first two-way switch, the comparator, second two-way switch and the electric capacity jointly to connect
Connect, and produce a temperature-independent clock signal of output frequency.
2. the RC oscillating circuits of low-temperature coefficient output frequency according to claim 1, it is characterised in that：Described second
The size of current that current source and the 3rd current source are produced is equal.
3. the RC oscillating circuits of low-temperature coefficient output frequency according to claim 1, it is characterised in that：Described first
One end connection power end of current source, the other end connects one end of the FET, the other end connection institute of the FET
One end of adjustable resistance is stated, the other end of the adjustable resistance connects one end of the resistance, the other end ground connection of the resistance.
4. the RC oscillating circuits of low-temperature coefficient output frequency according to claim 3, it is characterised in that：Described first
One connection end of two-way switch is connected at the tie point of first current source and the FET, first two-way switch
Another connection end be connected at the tie point of the adjustable resistance and the resistance, the control end of first two-way switch and institute
The positive input for stating comparator is connected.
5. the RC oscillating circuits of low-temperature coefficient output frequency according to claim 4, it is characterised in that：The comparison
The inverting input of device is connected with the control end of second two-way switch and one end of the electric capacity, the output end of the comparator,
The control end of first two-way switch and the control end of second two-way switch are commonly connected to the clock signal output terminal.
6. the RC oscillating circuits of low-temperature coefficient output frequency according to claim 5, it is characterised in that：Described second
One end connection power end of current source, the other end is connected with a connection end of second two-way switch, second two-way switch
Another connection end be connected with one end of the 3rd current source, the other end of the 3rd current source and the other end of the electric capacity
Ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610264112.7A CN107317567A (en) | 2016-04-26 | 2016-04-26 | The RC oscillating circuits of low-temperature coefficient output frequency |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610264112.7A CN107317567A (en) | 2016-04-26 | 2016-04-26 | The RC oscillating circuits of low-temperature coefficient output frequency |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109709999A (en) * | 2018-12-27 | 2019-05-03 | 普冉半导体（上海）有限公司 | Control the implementation method and circuit of output frequency temperature coefficient |
| CN109861688A (en) * | 2018-12-29 | 2019-06-07 | 成都锐成芯微科技股份有限公司 | A kind of clock generation circuit |
| CN109995325A (en) * | 2018-12-29 | 2019-07-09 | 成都锐成芯微科技股份有限公司 | A kind of low noise RC oscillator |
| CN114815950A (en) * | 2022-05-27 | 2022-07-29 | 浙江地芯引力科技有限公司 | Current generation circuit, chip and electronic equipment |
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| CN101977035A (en) * | 2010-11-19 | 2011-02-16 | 无锡灿星科技有限公司 | Temperature compensation offset eliminated RC oscillator |
| CN103475337A (en) * | 2013-08-30 | 2013-12-25 | 珠海中慧微电子有限公司 | RC (resistor-capacitor) oscillator |
| CN103580649A (en) * | 2012-07-31 | 2014-02-12 | 成都锐成芯微科技有限责任公司 | Low-detuning low-temperature-drift RC oscillator circuit with high power supply rejection ratio |
| US20140340164A1 (en) * | 2011-12-28 | 2014-11-20 | Denso Corporation | Cr oscillation circuit |
| CN104836577A (en) * | 2014-02-11 | 2015-08-12 | 无锡华润上华半导体有限公司 | High-precision oscillator structure suitable for MEMS application |
| CN205584150U (en) * | 2016-04-26 | 2016-09-14 | 成都锐成芯微科技有限责任公司 | Low temperature coefficient output frequence's RC oscillation circuit |
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2016
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| CN101977035A (en) * | 2010-11-19 | 2011-02-16 | 无锡灿星科技有限公司 | Temperature compensation offset eliminated RC oscillator |
| US20140340164A1 (en) * | 2011-12-28 | 2014-11-20 | Denso Corporation | Cr oscillation circuit |
| CN103580649A (en) * | 2012-07-31 | 2014-02-12 | 成都锐成芯微科技有限责任公司 | Low-detuning low-temperature-drift RC oscillator circuit with high power supply rejection ratio |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109709999A (en) * | 2018-12-27 | 2019-05-03 | 普冉半导体（上海）有限公司 | Control the implementation method and circuit of output frequency temperature coefficient |
| CN109709999B (en) * | 2018-12-27 | 2020-12-01 | 普冉半导体(上海)股份有限公司 | Method and circuit for controlling temperature coefficient of output frequency |
| CN109861688A (en) * | 2018-12-29 | 2019-06-07 | 成都锐成芯微科技股份有限公司 | A kind of clock generation circuit |
| CN109995325A (en) * | 2018-12-29 | 2019-07-09 | 成都锐成芯微科技股份有限公司 | A kind of low noise RC oscillator |
| CN109995325B (en) * | 2018-12-29 | 2023-05-30 | 成都锐成芯微科技股份有限公司 | Low-noise RC oscillator |
| CN114815950A (en) * | 2022-05-27 | 2022-07-29 | 浙江地芯引力科技有限公司 | Current generation circuit, chip and electronic equipment |
| CN114815950B (en) * | 2022-05-27 | 2024-03-12 | 浙江地芯引力科技有限公司 | Current generating circuit, chip and electronic equipment |
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Application publication date: 20171103 |
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