CN104596662B - Optimize digital temperature sensor on the piece of the linearity - Google Patents
Optimize digital temperature sensor on the piece of the linearity Download PDFInfo
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- CN104596662B CN104596662B CN201410742502.1A CN201410742502A CN104596662B CN 104596662 B CN104596662 B CN 104596662B CN 201410742502 A CN201410742502 A CN 201410742502A CN 104596662 B CN104596662 B CN 104596662B
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Abstract
The invention discloses digital temperature sensor on a kind of piece for optimizing the linearity, including a ring oscillator, for exporting the ring oscillator clock signal that a cycle is varied with temperature;Also include a time amplifier, its input is ring oscillator clock signal, so as to obtain a pulse signal for there are several ring oscillator clock signal Cycle Lengths;The digital temperature sensor also includes a counter, its input is above-mentioned pulse signal and a reference clock signal, when pulse signal arrives, is counted using reference clock, until pulse signal ends, therefore one is obtained with the count value that reference clock cycle is unit pulse signal length;While the advantages of digital temperature sensor of the present invention is retaining simple structure, area is small and low in energy consumption, with good linearity, the advantages of measurement temperature wide ranges and high precision, external crystal-controlled oscillation is may be omitted with, save cost.
Description
Technical field
The present invention relates to integrated circuit, particularly a kind of digital temperature sensor.
Background technology
Built-in temperature sensor typically has two kinds of frameworks, one is being examined using analog-digital converter (ADC) in voltage domain
The band gap voltage for surveying one and PTAT carrys out detection temperature;This band gap voltage is typically two VBE of triode
The poor Δ VBE of (emitter stage of triode BJT and the difference of base voltage).This temperature sensor have high precision, the linearity it is good,
Measurement temperature wide ranges and the low advantage of voltage sensitivity, but because ADC to be used is detected, so it has the disadvantage face
Product is big and power consumption is big;The second is in time-domain, temperature is detected by detecting on piece that the clock cycle varies with temperature clock
Degree.Due to not needing ADC to participate in, therefore this temperature sensor has the advantages that simple structure, area are small, low in energy consumption, but its
Shortcoming is exactly low precision, and not good enough, the measurement temperature narrow range of the linearity etc.;This temperature sensor can also be divided into some
Kind, it is referred to alternatively as delay line temperature sensor (Delay Line Temperature Sensor) or the temperature based on clock
Sensor (OSC Based Temperature Sensor), but due to its almost can all using Design of Digital Circuit, because
This is also referred to as digital temperature sensor.
Shown in Figure 1 is a kind of structure chart of aforementioned digital temperature sensor.Wherein Oscillator is an annular
Oscillator, can produce the clock signal of predetermined period Td, osc, and after Time Amplifier, the clock signal is put
One pulse Tp of great achievement;Pulse Tp is by reference clock REF and Counter count measurement (Time to a Digital
Converter, TDC), so as to obtain exporting Dout.If the cycle of reference clock REF is Tref, then Dout=Tp/Tref.
The pulse Tp that usual ring oscillator is produced has following expression formula:
Wherein L, W are the channel length and width of metal-oxide-semiconductor, and u, VTH are the mobility and threshold voltage of metal-oxide-semiconductor, and Cox is
The grid unit capacitance values of metal-oxide-semiconductor, and CL is load capacitance, VDD is supply voltage.Can substantially be derived according to this expression formula
The relation for drawing Tp and temperature is:
Tp∝Tempα
Wherein α is approximately equal to 0.7 or so, has certain deviation with different process.If using a reference clock for standard, example
UART clock is such as used, then the temperature coefficient of Tref is very small, therefore Dout's and temperature relation is determined by Tp substantially
It is fixed,
Dout∝Tempα
α is approximately equal to 0.7, so the linearity of the temperature sensor of this structure is not good enough, limits what it can be measured
Temperature range, reduces precision.
Therefore, it is necessary to improve the structure of current digital temperature sensor, make that its holding structure is simple, area is small, work(
While consuming low advantage, it is possible to increase its linearity, such that it is able to obtain preferably essence within the scope of broader temperature
Degree.
The content of the invention
Based on this, matter of utmost importance of the invention is to provide digital temperature sensor, the number on a kind of piece for optimizing the linearity
Word temperature sensor holding structure it is simple, area is small, it is low in energy consumption while, with the good linearity such that it is able to have
More preferable precision.
In order to solve the above-mentioned technical problem, the present invention provides digital temperature sensor on a kind of piece for optimizing the linearity, bag
A ring oscillator is included, for exporting the ring oscillator clock signal that a cycle is varied with temperature;When also including one
Between amplifier, its input be ring oscillator clock signal, for counting the clock signal, have several rings so as to obtain one
The pulse signal of shape oscillator clock signal Cycle Length;It is characterized in that the digital temperature sensor also includes a counting
Device, its input is above-mentioned pulse signal and a reference clock signal, when pulse signal arrives, using reference clock meter
Number, until pulse signal ends, therefore obtains one with the count value that reference clock cycle is unit pulse signal length;It is described
Reference clock signal clock cycle have a minus temperature coefficient;And the input of ring oscillator is terminated with control
Logic.
The ring oscillator, it is connected to form a ring and constitutes by a NAND gate and 6 phase inverters successively first place, its
The control signal of another input termination control logic of middle NAND gate.
The time amplifier is made up of a counter and a digital comparator;The count value of time amplifier passes through
Ntemp (Ntemp is a count value to ring oscillator number of cycles) sets, when the control signal of control logic is effective
Start the counting to ring oscillator clock signal;When the control signal of control logic is high, counter is started counting up, numeral
Pulse signal is put height by comparator, and when counting less than Ntemp, pulse signal puts height, and generation one feeds back signal to control
Logic, while feedback signal sets low;When count value is more than or equal to Ntemp, digital comparator sets low pulse signal, feedback letter
Number put height.
The clock cycle temperature coefficient of described reference clock is between -0.00095/ DEG C~-0.0.00045/ DEG C.
Preferably, the clock cycle temperature coefficient of described reference clock -0.00075/ DEG C~-0.0.00065/ DEG C it
Between.
Described reference clock is produced by RC oscillators.
Further, the RC oscillators timing resistor is by a positive temperature coefficient resistor and a negative temperature coefficient resister group
Into.
Further, the RC oscillators timing resistor by positive temperature coefficient NDIFF resistance and a negative temperature
The NPOLY resistance composition of coefficient.
Time amplifier trims circuit and (trims and realized by changing the value of Ntemp, that is, change including one
Become the clock signal number for counting ring oscillator), the number of ring oscillator clock signal is counted for trimming, generally, repair
Circuit is adjusted to be realized by counter.
Compared to traditional structure, simple structure, area be small and power consumption retaining for digital temperature sensor of the present invention
While low advantage, with good linearity, the advantages of measurement temperature wide ranges and high precision, external crystal-controlled oscillation is may be omitted with, saved
Cost is saved.
When using external crystal-controlled oscillation, power β=0.75 of the count value of counter and the power function relationship of temperature, and use this
During invention, β=0.98, it is clear that the linearity is much better than the situation using external crystal-controlled oscillation.In identical temperature range -40~85
DEG C, and under the linear fit solution of identical data, during using external crystal-controlled oscillation, temperature measurement accuracy is +/- 1.5 DEG C, and is used
During above-mentioned RC oscillators, precision is +/- 0.5 DEG C, and precision is increased dramatically.
Brief description of the drawings
Fig. 1 is the structure chart of prior art.
Fig. 2 is the structure chart that the present invention implements digital temperature control.
Fig. 3 is the circuit diagram of institute's implementation ring oscillator of the present invention.
Fig. 4 is the circuit diagram that the present invention implements time amplifier.
Fig. 5 is the circuit diagram that the present invention implements RC vibrators.
Specific embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
Referring to accompanying drawing 2, the preferred embodiment of digital temperature sensor of the present invention is shown.Including ring oscillator
Ring_osc1, time amplifier TimeAmp1, counter Counter1, RC oscillator RC_OSC1, and control logic
CtrlLogic1;Wherein ring oscillator module Ring_OSC1 simple structures, in control logic CtrlLogic1 control signals
When clk_en is effective, the ring oscillator clock signal clk_ring1 of some cycles can be produced, exported to time amplifier
TimeAmp1;TimeAmp1 is substantially one can be set with the counter of pre-set count values, count value by Ntemp;
TimeAmp1 starts the counting to clk_ring1 when clk_en is effective, and pulse signal Tp1 puts height, when Ntemp is count down to,
Pulse signal Tp1 sets low, and produces an eoc1 signal to give control logic CtrlLogic1;Counter1 is to use reference clock
What the length of ref_clk1 pulse signals Tp1 was counted, if the cycle of reference clock ref_clk1 is that then Counter1 is defeated for Tref1
The count value Dout1 for going out is determined by following formula:
Dout1=Tp1/Tref1
Reference clock ref_clk1 for counting is produced by RC_OSC1, and its cycle T ref1 has a negative temperature system
Number,
Tref1∝Tempβ
And pulse signal width Tp1 is then
Tp1∝Tempα
Therefore,
Dout1∝Tempα-β
If so that the relation of alpha-beta=1, Dout1 and temperature Temp is exactly to be a linear function.If α=0.7,
Then the power of the power function relationship of the cycle T ref1 and temperature of reference clock ref_clk should be set to -0.3 or so, if be converted into
Linear function, then the relation such as following formula of the cycle T ref1 of reference clock ref_clk and temperature:
Tref1=T0 (1+TC1Temp)
Wherein T0 is values of the Tref1 at reference temperature, such as 25 DEG C of room temperature, and TC1 is then the temperature coefficient of Tref1,
Preferred value should be at -0.0007/ DEG C or so.The factors such as the change in view of technique, the value of TC1-0.00095/ DEG C~-
All it is one optional between 0.00045/ DEG C.
Control logic CtrlLogic1 is also subjected to coming from chip main control section, such as control signal of MCU kernels
Start1, when start1 is effective, starting the digital temperature sensor carries out temperature survey;CtrlLogic1 can also be each
It is clear to be resetted to the register in TimeAmp1 and Counter1, counter etc. by rstb signals before carrying out temperature survey
Zero.
Referring to accompanying drawing 3, the internal circuit diagram of ring oscillator Ring_OSC1 is shown, it is anti-by a NAND gate and 6
First place is connected to form a ring composition, wherein another input termination control signal clk_en of NAND gate to phase device successively;When
When clk_en is high, Ring_OSC1 starts working, and exports a ring oscillator clock signal from ring_clk1;clk_en
For it is low when, Ring_OSC1 is stopped, and can save power consumption.
Referring to accompanying drawing 4, the internal circuit diagram of time amplifier TimeAmp1 is shown, it is mainly by a counter
Counter2 and digital comparator DCOMP1 composition;When clk_en is high, counter Counter2 starts counting up ring_
The number of clk1, and Tp1 is put height by DCOMP1, eoc1 sets low;When count value is more than Ntemp, DCOMP sets low Tp1, eoc1
Put height.
Referring to accompanying drawing 5, a kind of RC oscillators RC_OSC1 internal circuit diagrams are shown, be a kind of common RC oscillator knots
Structure.Wherein reference current IREF1 is mapped by current mirror M1 to M2, is flowed through R1 and is produced the first reference voltage VREF2, the second reference
Voltage is reference ground;Current mirror M3 produces one of the first charging and discharging currents IC2, first charge and discharge switch group by PMOS switch MS1+
Nmos switch MS2 is constituted, and terminates current mirror M3 drain electrode in the first charge and discharge switch group, lower end ground connection, in indirect first discharge and recharge
The top crown of electric capacity C1 and the negative terminal of first comparator CMP1;The second charge and discharge switch group is opened by PMOS switch MS3+NMOS
Close MS4 compositions, upper termination current mirror M3 drain electrodes, lower end ground connection, in indirect second charge and discharge capacitance C2 top crowns and the second ratio
Compared with the negative terminal of device CMP2;Charge and discharge capacitance C1 and charge and discharge capacitance C2 bottom crowns are grounded;The positive termination of comparator CMP1 and CMP2
Reference voltage VREF2, output meets control logic contro l_logic2;The control logic includes a rest-set flip-flop and one
Buffer stage is constituted;When CMP2 negative terminal voltages are more than VREF2, φ 22 is uprised, and MS4 conductings, MS3 disconnects, and C2 starts electric discharge;And it is same
When the step-downs of φ 21, MS1 conductings, MS2 disconnects, and C1 starts to charge up;Ref_clk1 is the reference clock letter by being exported after buffer stage
Number.The mapping ratio of usual above-mentioned current mirror is 1:1.In the ideal case, the time of comparator CMP1/CMP2 singles upset
It is C1*VREF2/IC2 or C2*VREF2/IC2;In order that clock signal duty cycle is consistent, usual C1=C2;Therefore refer to clock
Cycle T ref1 is 2*C1*VREF2/IC2;And VREF2=IC2*R1;So Tref1=2*C1*R1, therefore C1 is timing electricity
Hold, and R1 is timing resistor.General electric capacity C1 has the temperature coefficient of very little, and the temperature coefficient of Tref1 is mainly determined by R1, and
The temperature coefficient of R1 is determined by the manufacturing process and specific resistance device used of chip again.In order to obtain a suitable temperature
The R1 of coefficient, can typically obtain by by a positive temperature coefficient resistor and a negative temperature coefficient resister combination.Typically
Positive temperature coefficient resistor can use NDIFF resistance, and negative temperature coefficient resister can use NPOLY resistance.
Referring to table 1, the digital temperature sensor of the optimization linearity of the present invention and an effect of first technology are shown
Fruit contrasts.When using external crystal-controlled oscillation, power β=0.75 of the power function relationship of Dout1 and temperature, and using has -0.0007/
During the RC oscillators of DEG C temperature coefficient, β=0.98, it is clear that the linearity is much better than the situation using external crystal-controlled oscillation.In identical
Under temperature range -40~85 DEG C, and the linear fit solution of identical data, during using external crystal-controlled oscillation, temperature measurement accuracy is
+/- 1.5 DEG C, and when using above-mentioned RC oscillators, precision is +/- 0.5 DEG C, is substantially improved.
Table 1
Presently preferred embodiments of the present invention is the foregoing is only, is not intended to limit the invention, it is all in essence of the invention
Any modification, equivalent and improvement made within god and principle etc., should be included within the scope of the present invention.
Claims (8)
1. digital temperature sensor on a kind of piece for optimizing the linearity, an including ring oscillator, for exporting a cycle
The ring oscillator clock signal for varying with temperature;Also include a time amplifier, its input is believed for ring oscillator clock
Number, for counting the clock signal, believe so as to obtain a pulse for there are several ring oscillator clock signal Cycle Lengths
Number;It is characterized in that the digital temperature sensor also includes a counter, its input is above-mentioned pulse signal and one
Reference clock signal, when pulse signal arrives, is counted using reference clock, until pulse signal ends, therefore obtains one
With the count value that reference clock cycle is unit pulse signal length;The clock cycle of described reference clock signal has one
Minus temperature coefficient;And the input of ring oscillator is terminated with control logic.
2. digital temperature sensor on the piece of the linearity is optimized as claimed in claim 1, it is characterised in that the ring oscillation
Device, it is connected to form a ring and constitutes by a NAND gate and 6 phase inverters successively first place, wherein another input of NAND gate
Terminate the control signal of control logic.
3. digital temperature sensor on the piece of the linearity is optimized as claimed in claim 1, it is characterised in that the time-reversal mirror
Device is made up of a counter and a digital comparator;The count value of time amplifier is set by Ntemp, in control logic
Control signal it is effective when start counting to ring oscillator clock signal;When the control signal of control logic is high, meter
Number device is started counting up, and pulse signal is put height by digital comparator, and when counting less than Ntemp, pulse signal puts height, and produces one
It is individual to feed back signal to control logic, while feedback signal sets low;When count value is more than or equal to Ntemp, digital comparator is by arteries and veins
Rush signal to set low, feedback signal puts height.
4. digital temperature sensor on the piece of the optimization linearity as claimed in claim 1, it is characterised in that during described reference
The clock cycle temperature coefficient of clock is between -0.00095/ DEG C~-0.0.00045/ DEG C.
5. digital temperature sensor on the piece of the optimization linearity as claimed in claim 4, it is characterised in that during described reference
The clock cycle temperature coefficient of clock is between -0.00075/ DEG C~-0.0.00065/ DEG C.
6. digital temperature sensor on the piece of the optimization linearity as claimed in claim 1, it is characterised in that during described reference
Clock is produced by RC oscillators.
7. digital temperature sensor on the piece of the linearity is optimized as claimed in claim 6, it is characterised in that the RC oscillators
Timing resistor is made up of a positive temperature coefficient resistor and a negative temperature coefficient resister.
8. digital temperature sensor on the piece of the linearity is optimized as claimed in claim 7, it is characterised in that the RC oscillators
Timing resistor is made up of the NDIFF resistance of positive temperature coefficient and the NPOLY resistance of a negative temperature coefficient.
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CN106918354B (en) * | 2015-12-28 | 2019-07-26 | 上海新微技术研发中心有限公司 | Sensing system and applicable sensing information determination method |
CN105628243B (en) * | 2015-12-30 | 2018-04-20 | 清华大学深圳研究生院 | A kind of resistor-type temperature sensing chip |
CN106788266B (en) * | 2016-11-18 | 2019-12-17 | 杭州电子科技大学 | RC oscillator with high oscillation frequency |
JP6678094B2 (en) * | 2016-12-05 | 2020-04-08 | ルネサスエレクトロニクス株式会社 | Temperature measurement circuit, method, and microcomputer unit |
CN106840440B (en) * | 2017-03-03 | 2023-07-28 | 成都信息工程大学 | Temperature collector based on MCU internal comparator and temperature collection method |
CN109632117B (en) * | 2017-05-24 | 2020-09-11 | 杭州电子科技大学 | On-chip temperature detection method based on RC oscillator |
EP3438620B1 (en) * | 2017-08-02 | 2020-09-30 | Melexis Technologies NV | Closed-loop oscillator based sensor interface circuit |
CN107830940A (en) | 2017-10-13 | 2018-03-23 | 京东方科技集团股份有限公司 | A kind of temperature sensor, array base palte, display device |
CN110260986B (en) * | 2019-06-28 | 2020-08-28 | 上海视欧光电科技有限公司 | Temperature detection device and method and display system |
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Address after: 518000, A building, block 9, garden city digital garden, 1079 Nanhai Road, Guangdong, Shenzhen, Nanshan District Patentee after: Chipsea Technology (Shenzhen) Co., Ltd. Address before: 518067 Nanshan District, Shenzhen, Nanhai Avenue, garden city, No. 1079, building A, block, floor 9 Patentee before: Xinhai Science and Technology Co., Ltd., Shenzhen City |