Radio temperature sensor chip
Technical field
The present invention relates to a kind of radio temperature sensor chip.
Background technology
Enter after 21 century, self-energizing intelligent wireless temperature sensor just develops rapidly towards high-tech directions such as high precision, multi-functional, bus standard, high reliability and security, development of virtual sensor and network sensor, development monolithic temp measuring systems.
Traditional radio temperature sensor generally adopts powered battery, although the energy storage density of battery and serviceable life are along with technical progress improves constantly, but still the energy supply defect that exists some to overcome, limited such as the energy supply life-span, need recharge, volume and quality larger etc., can not meet the demand for development of wireless sensor network completely.Along with the widespread use of wireless sensor network, interstitial content is more and more huger, adopts the defect of powered battery mode further to show.In recent years, self energizing technology is suggested as a kind of method that can fundamentally solve wireless sensor network node energy supply problem, it is a kind of by collecting in surrounding environment other forms of energy and converting thereof into electric energy, for sensor and other electronic equipment provide safety, stable, efficiently, in theory without the electric energy supply technology of age limit.The advantage of self energizing technology maximum is that wireless senser can utilize energy in the surrounding environment Power supply as self, thereby has broken away from the dependence to electrical network.Because the self-supporting feature that it is unique, the developing direction of coincidence senser and industry need, and its development prospect is very wide.
Michiel A. P. Pertijs in 2005 etc. have delivered high-precision intelligent temperature sensor, its principle is the PTAT voltage producing based on triode transistor, by sigma-delta formula A/D converter, having realized from the 3 σ errors of-50 ℃ to 120 ℃ is only the intelligent temperature sensor of ± 0.5 ℃; The people such as Faith Kocer in 2006 have realized the signal-powered radio temperature sensor with RF, and wireless transmit frequency is 2.3 GHz, stand-by power consumption 5 μ A, and power 5mA while transmitting, but communication distance is shorter; Fabio Zito in 2010 etc. have delivered for biomedical radio temperature sensor, this chip adopts triode transistor to produce PTAT voltage, by 8bit digital to analog converter, data are offered to radio-frequency module transmitting, this chip is integrated in radio-frequency antenna the miniaturization that has realized chip on chip.The research of above academia has tentatively realized the integrated of temperature measurement circuit, radio communication circuit, but the self-energizing of unrealized system also, and research is not be directed to electrical power transmission system mostly, does not relate to the research contents of the aspects such as Anti-interference Design.
From the investigation situation of overseas enterprise's product, the chip that offshore company provides all lays particular emphasis on mostly separately to be realized radio communication function with a chip, as the CC1100 of the NRF2401 of the ADF7021 of ADI company, Nordic company, TI company etc.Composition is when wireless temperature sensing system, also need to be in system integrated independently ADC and processor chips etc., such implementation has larger Universal and scalability, still, this mode will cause volume, the cost of system higher.In addition, the chip of offshore company's exploitation is normally for global radio band planning, the 470MHz that only has only a few product can cover China measures frequency range, and what also there is no at present that the chip of a offshore company can meet requirements at the higher level gets energy, thermometric, AD conversion, radio communication and networking protocol processes.
Due to the relatively evening of integrated circuit (IC) design industry development of China, designed capacity fermentation at chip is larger with Foreign Advanced Lerel gap, especially in field of power, at present domestic self-energizing radio temperature sensor equipment mainly assembles by buying external chip, the self-energizing wireless temperature sensing special chip with Low Power High Performance of autonomous Design research and development not yet has play-by-play, but also have made some progress in some field, but function is limited, cannot meets the demand in market.
Summary of the invention
The object of the present invention is to provide a kind of radio temperature sensor chip, mainly solve a kind of safe and reliable, radio temperature sensor chip that power consumption is lower of the shortage existing in prior art, can not meet the problem of technical development demand.
To achieve these goals, the technical solution used in the present invention is as follows:
Radio temperature sensor chip, comprising:
Power Management Unit, supports the input of front end self-energizing installation's power source and external power supply input, adopts high voltage bearing LDMOS pipe to be designed to LDO structure;
Temperature sensor unit, detection chip environment temperature around, and produce overheat protector signal during higher than threshold value in temperature;
Band-gap reference unit provides and stablizes constant DC reference voltage to AD converting unit in the temperature range of setting, and provides stable voltage or current offset for other unit in chip;
ADC unit, the reference signal that the signal sampling and band-gap reference unit are provided successively compares, and draws each digital conversion results, realizes the AD conversion of signal;
Charged detecting unit, judges that whether equipment to be detected is charged;
Transmit Receive Unit, carries out signal transmitting and receiving and processing;
Described Power Management Unit, temperature sensor unit, band-gap reference unit, ADC unit, charged detecting unit and Transmit Receive Unit all integrate.
Further, described Transmit Receive Unit comprises GFSK radio frequency sending set, the GFSK radio-frequency transmitter that the signal of GFSK radio frequency sending set transmitting is received, and the processing unit processed of the signal that GFSK radio-frequency transmitter is received.
Described GFSK radio frequency sending set is realized based on a decimal N-type frequency synthesizer; Described GFSK radio-frequency transmitter comprises connected successively low noise amplifier, down-conversion mixer, complex bandpass filters, the limiter being made up of N level logarithmic amplifier and the ADC converter that carries out signal AD conversion.
Specifically, described Power Management Unit comprises the biasing circuit being connected with power input, the metal-oxide-semiconductor M3 that source electrode is connected with biasing circuit, grid is all connected with the drain electrode of metal-oxide-semiconductor M3, and the interconnective metal-oxide-semiconductor M1 of source electrode and metal-oxide-semiconductor M2, the triode Q1 that collector is connected with the drain electrode of metal-oxide-semiconductor M1, emitter is connected with the emitter of triode Q1 by resistance R 1, the triode Q2 that collector is connected with the drain electrode of metal-oxide-semiconductor M2, source electrode is connected with the drain electrode of metal-oxide-semiconductor M2, the metal-oxide-semiconductor M4 that grid is connected with the base stage of triode Q2 by resistance R 3, the triode Q3 that collector is connected with the grid of metal-oxide-semiconductor M4, the triode Q4 that base stage is connected with the base stage of triode Q3, source electrode is connected with biasing circuit, the metal-oxide-semiconductor M8 that drain electrode is connected with the grid of metal-oxide-semiconductor M4, grid is connected with the grid of metal-oxide-semiconductor M8, the metal-oxide-semiconductor M7 that drain electrode is connected with the collector of triode Q4, the metal-oxide-semiconductor M6 that source electrode is connected with the source electrode of metal-oxide-semiconductor M7, drain electrode is connected with the drain electrode of metal-oxide-semiconductor M6, the metal-oxide-semiconductor M5 that source electrode is connected with the grid of metal-oxide-semiconductor M4.
Wherein, described temperature sensor unit comprises PTAT current source, the temperature sensor output circuit being connected with PTAT current source, the thermal-shutdown circuit being connected with temperature sensor output circuit.
In the present invention, described PTAT current source comprises the interconnective triode Q12 of base stage and triode Q32, the triode Q22 that base stage is connected with the emitter of triode Q32, collector is connected with the emitter of triode Q12, the triode Q42 that base stage is connected with the emitter of triode Q12, collector is connected with the emitter of triode Q32, and be connected in the resistance R 12 between emitter and the ground of triode Q22.
Further, described band-gap reference unit comprises the slide rheostat R7a of series connection, resistance R 8a, resistance R 8b and slide rheostat R7b, in-phase input end is connected with the sliding end of slide rheostat R7a, the operational amplifier T that inverting input is connected with the sliding end of slide rheostat R7b, the interconnective triode Q13 of base stage, triode Q23, triode Q43 and triode Q53, emitter is connected between resistance R 8a and resistance R 8b, base stage is connected in the triode Q33 of triode Q53 collector by resistance R 83, the collector of described triode Q13 is connected with the stiff end of slide rheostat R7a, emitter is connected with the emitter of triode Q23 by resistance R 13, the collector of described triode Q23 is connected with the stiff end of slide rheostat R7b.
Compared with prior art, the present invention has following beneficial effect:
(1) Power Management Unit in the present invention had both been supported the power supply input of energy taking device, also support the input of external power supply, and can design by high voltage bearing LDMOS pipe in adopting process, thereby can adapt to the temperature survey under varying environment, and chip can be measured ambient temperature by the temperature sensor unit of self, also can use external temperature survey sensor to measure, use flexibly, applied widely.
(2) in the present invention, by the ingehious design to band-gap reference unit, make chip can steady operation in the temperature range of technical requirement, and for other circuit provide reliable voltage or current offset, thereby greatly improve the temperature reliability of whole chip.
(3) in the present invention, adopt successive approximation structure to realize the AD conversion of temperature signal, there is the advantage of simple in structure, low cost, low-power consumption, and by Transmit Receive Unit being designed to the heterodyne architecture of Low Medium Frequency, effectively reduce power consumption and the cost of chip, solved local-oscillator leakage in zero intermediate frequency reciver, even nonlinearity, direct current offset, flicker noise and be subject to the large problems such as I/Q mismatch affects.
(4) the present invention simple in structure, design ingenious, working stability, cost performance is higher, has outstanding substantive distinguishing features and marked improvement, is applicable to large-scale promotion application.
Accompanying drawing explanation
Fig. 1 is enforcement schematic diagram of the present invention.
Fig. 2 is the circuit theory diagrams of Power Management Unit in the present invention.
Fig. 3 is the circuit theory diagrams of temperature sensor unit in the present invention.
Fig. 4 is the circuit theory diagrams of band-gap reference unit in the present invention.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described, and embodiments of the present invention include but not limited to the following example.
Embodiment
Safe and reliable in order to solve the shortage one existing in prior art, the radio temperature sensor chip that power consumption is lower, can not meet the problem of technical development demand, as shown in Fig. 1 ~ 4, the invention provides a kind of security performance high, reliability is strong, radio temperature sensor chip low in energy consumption, mainly comprise Power Management Unit, temperature sensor unit, band-gap reference unit, ADC unit, charged detecting unit, the parts such as Transmit Receive Unit, Power Management Unit support comprises CT energy taking device, the multiple front end self-energizing installation's power source input such as field coupled energy taking device, also support the input of external power supply, the mode of collecting temperature is the inner integrated temperature sensor unit of supporting chip both, also supports the mode of outside cut-in temperature sensor.
Can be used for hyperbaric environment in order to ensure chip and also can be applied to environment under low pressure, based on the feature of energy taking device of the present invention, and the feature of power equipment applied environment, as shown in Figure 2, Power Management Unit realizes based on LDO structure, and consider that energy taking device may export higher voltage, therefore in adopting process, can design by high voltage bearing LDMOS pipe.
A kind of circuit theory diagrams of Power Management Unit are provided in the present embodiment, as shown in Figure 2, whole LDO circuit is using the high pressure HV_IN of energy taking device output as power supply, produce the auxiliary moding circuit of band-gap reference unit by simple biasing circuit (two, the left side), triode Q1 and triode Q2, as scale tube, produce △ V
bE(emitter is with respect to the voltage of base stage), guarantees that by current mirror M1 and M2 two branch currents equate, bandgap voltage reference, after A point produces, is boosted and reached V by resistance R 3 and R4 ratio
b, and then deduct V
gS5(in metal-oxide-semiconductor M5, grid is with respect to the voltage of source electrode) thus obtain AVDD.Wherein, metal-oxide-semiconductor M4, M5, M6, M7, M8 and triode Q2, Q3 form a simple backfeed loop jointly, realize the automatic adjusting of AVDD, in the time that AVDD voltage is dragged down, metal-oxide-semiconductor M5 electric current increases, by the feedback of current mirror, B point voltage is by drop-down, now at the V of metal-oxide-semiconductor M4
gScan rise, thereby will on B electrical voltage point, draw, and then AVDD is raised, complete feedback, design by sort circuit, in the time that AVDD does not drive load, the power consumption of LDO circuit is extremely low, is about 30uA.
Temperature sensor unit is an integrated semiconductor devices temperature sensor circuit; for detection of chip environment temperature around; and the overheat protector signal of whole chip also produces based on this circuit; in the present invention; the mode of collecting temperature is the inner integrated temperature sensor unit of supporting chip both; also support the mode (as platinum sensor etc.) of outside cut-in temperature sensor, thereby temperature sensor unit can be integrated in chip exterior, also can be integrated in chip internal.
The circuit theory diagrams of a kind of temperature sensor unit are provided in the present embodiment, and as shown in Figure 3, the circuit in the dotted line frame of the left side produces a PTAT electric current I
pTAT, the ratio of the launch site area of the size of this electric current and resistance R 12 and four triode Q12, Q22, Q32, Q42 is relevant, and this electric current produces temperature voltage signal through the current mirror of P1 and P3 composition; In this circuit, rightmost part is thermal-shutdown circuit, and after the normal work of circuit, A, B point voltage are high voltage, and C point voltage is low-voltage, now A point voltage V
a=I
pTAT* R32, along with the rising of temperature, A point voltage also raises, and in the time reaching certain temperature, A point voltage reaches the threshold voltage of triode Q52, triode Q52 conducting in the time exceeding this temperature, after its conducting, B point voltage becomes low-voltage, and now A point voltage becomes V
a=I
pTAT* (R32+R42), therefore B point signal can be used as the overheat protector indicator signal of full chip.
The function of band-gap reference unit be make chip can reliably working in the temperature range requiring, in whole temperature range, provide and stablize constant DC reference voltage, for AD converting unit provides reference voltage, and provide reliable voltage or current offset for other unit of full chip, thereby greatly improve the temperature reliability of whole chip, according to actual conditions, voltage temperature coefficient can be less than 10ppm/ ℃.
The circuit theory diagrams of a kind of band-gap reference unit are provided in the present embodiment, as shown in Figure 4, the ratioed transistor that reference circuit is made up of triode Q13 and Q23 produces, and then the signal of generation is sent into the divider resistance string being made up of resistance R 43, R53, R63, produces required reference voltage V
rEF, wherein, resistance R 53 and R7a, R7b can carry out T
rIMthe adjustable resistance (as slide rheostat) regulating, be used for improving resistance precision, triode Q43, Q53 and P4, P5(P can adopt the device such as metal-oxide-semiconductor, operational amplifier, as long as can realize corresponding function just can) generate triode Q33 required voltage, also introduce negative feedback simultaneously, improve loop stability, adjustable resistance R53 is mainly used to produce dividing potential drop, to produce accurately required reference voltage V
rEF, P6 is reference voltage V together with operational amplifier T
rEFnecessary driving force is provided, produces feedback control loop by operational amplifier T simultaneously, reduce because load variations is to V
rEFimpact.
In order to improve chip performance, to reduce power consumption, ADC unit in the present invention adopts successive approximation structure, in order to realize the AD conversion of temperature signal, with respect to the ADC unit of other form, adopt successive approximation structure to there is the clear superiority of simple in structure, low cost, low-power consumption.The ADC unit of this kind of structure can comprise 16 ratio electric capacity, a series of gauge tap and a comparer, under the control of logical circuit, the analog temperature signal that it obtains sampling successively compares with reference signal, draw each digital conversion results, because the control of circuit is mainly completed by digital circuit, therefore there is extremely low power consumption.
Whether charged detecting unit judges that in normal output state whether monitored equipment is charged by current induction energy fetching device, can, by charged information output, realize equipment HV live displaying and blocking function thereby assist simultaneously.
Transmit Receive Unit comprises GFSK radio-frequency transmitter, GFSK radio frequency sending set, the processing unit being formed by digital base band processor module and MAC layer processing module, be that radio frequency transceiver comprises and transmits and receives two large divisions, and can realize and transmit and receive multiplexing in time domain by transmit-receive switch on a sheet.In order to reduce power consumption and the cost of chip, whole receiving cable can adopt the heterodyne architecture of Low Medium Frequency, adopt low intermediate frequency structure only to need single-conversion, simple in structure, cost is suitable with zero intermediate frequency formula receiver, but can effectively solve local-oscillator leakage in zero intermediate frequency reciver, even nonlinearity, direct current offset, flicker noise and be subject to the large problem such as I/Q mismatch affects, in receiver path, can comprise low noise amplifier, down-conversion mixer, complex bandpass filters, limiter and one realize the ADC of receiving intensity indicator signal AD conversion etc., because the transceiver of this kind of structure belongs to mature technology in prior art, thereby more do not speak more bright at this.
In the present invention, different from the transmitter of other conventional modulated pattern, transmitter in the present invention does not have up-conversion mixer, but realize based on a decimal N-type frequency synthesizer, and baseband circuit digital circuit and MAC protocol process module circuit all adopt digital circuit hardware to realize, the receiving unit of baseband circuit is in order to realize further channel filtering, GFSK demodulation, automatic gain control (AGC), frame synchronization; Radiating portion is realized the functions such as emissive power control, channel selection and GFSK frequency shift (FS) control.
In order to realize above-mentioned functions, in the present embodiment, provided a kind of circuit structure diagram of Transmit Receive Unit, GFSK radio-frequency transmitter comprises that connected successively low noise amplifier, down-conversion mixer, complex bandpass filters, the limiter being made up of N level logarithmic amplifier and one realize the ADC converter of receiving intensity indicator signal AD conversion.Wherein, low noise amplifier amplifies radiofrequency signal to restrain the noise of late-class circuit, frequency mixer is realized the quadrature frequency conversion of radiofrequency signal, intermediate frequency by signal frequency conversion to 2MHz, complex bandpass filters is carried out channel selection and image frequency suppresses, thereby avoids using the intermediate-frequency filter outside sheet, and complex filter preferably adopts activated amplifier structure, certain adjustable gain is provided, and filtered intermediate-freuqncy signal carries out entering base-band digital circuit after limited range enlargement through limiter.Wherein, amplitude limiter circuit is equivalent to the ADC converter of 1 bit, can receiving intensity indicator signal by its special logarithmic amplifier cascade structure, to assist base-band digital circuit to realize automatic gain control, and judge that whether channel is idle.In order to realize automatic gain control, low noise amplifier in the present invention and the gain of active band-pass filter all can be configured by base-band digital circuit, in order to reduce the frequency of operation of baseband circuit, the centre frequency of intermediate-freuqncy signal can be defined as 1MHz, adopt lower sideband injection mode, namely make local oscillation signal lower than radio-frequency carrier signal, for example radiofrequency signal is 472MHz, local oscillation signal is 470MHz, and the local oscillation signal frequency of each channel by that analogy.
GFSK radio frequency sending set does not have up-conversion mixer, but realize based on a decimal N-type frequency synthesizer, under emission mode, the numerical information of digital baseband circuit output is through GFSK modulation, carry out respectively again gaussian filtering and Digital Modulation, thereby the radiofrequency signal that whole decimal frequency divider output is controlled through GFSK, this signal is gone out from antenna transmission after passing through power amplification again.GFSK signal is constant envelope signal, so the power amplifier in the present invention preferably adopts high efficiency E class A amplifier A to realize, to reduce the power consumption of power amplifier, and can realize on the sheet of power amplifier integrated.The emissive power of power amplifier can be controlled and be configured by base-band digital circuit, generally, and the V in frequency synthesizer
cOfrequency of operation is the twice of carrier frequency, through after high speed orthogonal two divided-frequency, and outgoing carrier frequency, and provide down coversion required local oscillation signal for receiver.
According to above-described embodiment, just can realize well the present invention.