CN101586987B

CN101586987B - Temperature sensing circuit suitable for operation at low voltage

Info

Publication number: CN101586987B
Application number: CN2008100982368A
Authority: CN
Inventors: 戴枝德
Original assignee: TAI-1 MICROELECTRONICS CORP
Current assignee: Dai Zhide
Priority date: 2008-05-23
Filing date: 2008-05-23
Publication date: 2011-04-20
Anticipated expiration: 2028-05-23
Also published as: CN101586987A

Abstract

The invention relates to a temperature sensing circuit suitable for operation at low voltage, which mainly comprises a temperature sensing unit, a temperature threshold controlling unit and a trsanscondutance amplifier, wherein the temperature sensing unit comprises PMOS transistors and bipolar transistors and has the function of sensing the temperature of a circuit through voltage; the temperature threshold controlling unit comprises NMOS transistors and PMOS transistors and is mainly used for supplying an overtemperature warning signal to the temperature sensing unit when the overtemperatureis detected, and the overtemperature warning signal can be always in a starting state until the value of the temperature is reduced to a definite value; and the trsanscondutance amplifier also compri ses NMOS transistors and PMOS transistors. The invention mainly provides the temperature sensing circuit suitable for operation at low voltage. In addition, the framework of the temperature sensing circuit suitable for operation at low voltage can be realized without using any operation amplifier and bandgap reference voltage sources, therefore, the manufacturing cost can be saved.

Description

Be applicable to the temperature sense circuit of low-voltage running

Technical field

What the present invention relates to is a kind of semi-conductive integrated circuit, particularly be a kind of temperature sense circuit that contains temperature door control module.

Background technology

Along with electronic product usefulness is constantly weeded out the old and bring forth the new, more and more Duo function is incorporated into mutually in all kinds of appliance and electronics, as mobile phone and camera and MP3 player or laptop computer and also multiple multimedia integration.Yet in the integration of every function, in order to satisfy the support of difference in functionality, more and more Duo chipset need be placed in appliance and electronic, is simultaneously also representing more heat to produce along with the frequency of chipset such as CPU also improves constantly.If, not only cause the loss of data and the instability of system easily because the system temperature of appliance and electronic is too high, serious words even can cause burning of chip.Because external temperature sensing component not only can increase production cost of products, precision also can't be certain grasp, therefore be the method that present electronic product the most generally uses by adding the temperature sense circuit in IC itself, it has the degree of accuracy height, response speed is fast, volume is little, power consumption is little, software interface is controlled advantages such as easy to use.

The temperature sense circuit generally can allow the user set the temperature range of running, then automatically performs the method for cooling or directly IC is decommissioned as long as surpass this scope.At present the main mechanism of general temperature sensing is the current source and the analog-digital converter of IC temperature inductor inside, the operating principle of IC temperature inductor be utilize semiconductor PN interface forward the pressure drop characteristic that under different temperature, has different forward pressure drops come measuring temperature.Yet all at present temperature sense circuit need an extra operational amplifier (Operational Amplifier) and the bandgap voltage reference of adding mostly, not only can improve the cost in the design, also are not suitable for overlapping on the circuit that is used in low-voltage.At present general temperature sense circuit itself does not have the door control function, temperature sense circuit and door control circuit all by separately independently circuit realize that serial connection mutually not only causes deviser's inconvenience in design again, raising production cost easily also.

In order to address the above problem, the present invention proposes a kind of temperature sense circuit that is applicable to the low-voltage running, not only comprise temperature door control module and drop to certain value, do not need utilization and operation amplifier and bandgap voltage reference to reach the saving of manufacturing cost simultaneously so that the caution signal during the circuit excess temperature can start up to temperature always.

Summary of the invention

Fundamental purpose of the present invention is that a kind of temperature sense circuit is being provided, particularly a kind of temperature sense circuit of being made up of temperature induction unit, temperature door control module and trsanscondutance amplifier, wherein temperature door control module is directly controlled the state of temperature induction unit.The present invention not only can testing circuit temperature, the caution signal in the time of also allowing excess temperature can start up to temperature always and drops to certain value, can allow the present invention be useful in the low-voltage running by trsanscondutance amplifier simultaneously.

Temperature induction unit wherein, has the function of coming the sensor circuit temperature by voltage, comprise one the one PMOS transistor, its grid is connected an output current with drain electrode, source electrode then is to connect a Vdd voltage, one the 2nd PMOS transistor, its grid also connects described output current end, source electrode also obtains described Vdd voltage, one the 3rd PMOS transistor, its grid also connects described output current end, source electrode also obtains described Vdd voltage and drains and then connect a resistance, the other end ground connection of wherein said resistance and a PNP bipolar transistor, its emitter-base bandgap grading connect then ground connection in pairs of described the 2nd PMOS transistor drain base stage and the collection utmost point.Temperature door control module, provide temperature induction unit when detecting excess temperature, the excess temperature caution signal can start always and drops to certain value up to temperature and comprise one the 4th PMOS transistor, its grid connects described output current end, source electrode obtains described Vdd voltage, one first nmos pass transistor, its grid and drain electrode are connected together and overlap with described the 4th PMOS transistor drain, source electrode then is a ground connection, one second nmos pass transistor, the grid of its grid and described first nmos pass transistor joins, source electrode then is a ground connection, and one the 3rd nmos pass transistor, its drain electrode connects the emitter-base bandgap grading of described PNP bipolar transistor, and its source electrode then connects the drain electrode of described second nmos pass transistor.Trsanscondutance amplifier, voltage ratio function mainly is provided, but can make whole temperature sense circuit can be useful in the low-voltage running, comprise one the 5th PMOS transistor, its source electrode obtains described Vdd voltage, grid connects described output current end, one the 6th PMOS transistor, its source electrode also obtains described Vdd voltage, and grid also connects described output current end, a caution signal is then exported in drain electrode, one the 7th PMOS transistor, its source electrode connects described the 5th PMOS transistor drain, grid connects described the 3rd PMOS transistor drain, one the 8th PMOS transistor, its source electrode connects the transistorized source electrode of described the 7th PMOS, grid connects the emitter-base bandgap grading of described PNP bipolar transistor, one the 4th nmos pass transistor, its drain electrode is joined with grid and is connected described the 7th PMOS transistor drain, its source electrode is ground connection then, one the 5th nmos pass transistor, its drain electrode connects described the 8th PMOS transistor drain, its grid is then received the grid of described the 4th nmos pass transistor, source electrode then is a ground connection, one the 6th nmos pass transistor, its drain electrode connects described caution signal, grid connects the drain electrode of described the 5th nmos pass transistor, and source electrode is a ground connection and a not gate too, its input end connects described caution signal, and output terminal then connects the grid of described the 3rd nmos pass transistor.

Description of drawings

Fig. 1 is applicable to the circuit diagram of the temperature sense circuit of low-voltage running for the present invention;

Fig. 2 is applicable to the temperature induction unit circuit diagram of the temperature sense circuit of low-voltage running for the present invention;

Fig. 3 is applicable to the transconductance amplifier circuit synoptic diagram of the temperature sense circuit of low-voltage running for the present invention;

Fig. 4 is applicable to the test simulation result schematic diagram of the temperature sense circuit of low-voltage running for the present invention.

Description of reference numerals: 1-PMOS transistor; The 11-NMOS transistor; The 2-PMOS transistor; The 12-NMOS transistor; The 3-PMOS transistor; The 13-NMOS transistor; The 4-PMOS transistor; The 14-NMOS transistor; The 5-PMOS transistor; The 15-NMOS transistor; The 6-PMOS transistor; The 16-NMOS transistor; The 7-PMOS transistor; 17-resistance; The 8-PMOS transistor; The 18-temperature induction unit; The 9-bipolar transistor; 19-temperature door control module; The 10-not gate; The 20-trsanscondutance amplifier.

Embodiment

Below in conjunction with accompanying drawing, be described in more detail with other technical characterictic and advantage the present invention is above-mentioned.

The invention discloses a kind of temperature sense circuit, particularly a kind of temperature that not only can testing circuit, the caution signal in the time of also allowing excess temperature can start up to temperature always and drops to certain value, is useful in the temperature sense circuit of low-voltage running simultaneously.

Fig. 1 is a circuit diagram of the present invention, is one of preferred embodiment of the present invention, mainly is to be made of temperature induction unit 18, temperature door control module 19 and trsanscondutance amplifier 20.Temperature induction unit mainly has the function of reacting circuit temperature by voltage, its framework is made up of following assembly as shown in Figure 2: PMOS transistor 1, its grid is connected an output current with drain electrode, source electrode then is to connect a Vdd voltage, PMOS transistor 2, its grid also connects described output current end, source electrode also obtains described Vdd voltage, PMOS transistor 3, its grid also connects described output current end, source electrode also obtains described Vdd voltage and drains and then connect a resistance 17 (Rnw), the other end ground connection of wherein said resistance and a PNP bipolar transistor 9, its emitter-base bandgap grading connect then ground connection in pairs of the drain electrode base stage of PMOS transistor 2 and the collection utmost point.

Temperature door control module 19 mainly is to provide temperature induction unit 18 when detecting excess temperature, the caution signal that is sent can start up to temperature always and drops to certain value, and its framework mainly comprises: PMOS transistor 4, its grid connects described output current end, source electrode obtains described Vdd voltage, nmos pass transistor 11, its grid and drain electrode be connected together and with the drain electrode of PMOS transistor 4 overlap joint, source electrode then is a ground connection, nmos pass transistor 12, its grid and nmos pass transistor 11 join, source ground and nmos pass transistor 13, the emitter-base bandgap grading (Emitter) of PNP bipolar transistor 9 is received in its drain electrode, and its source electrode then connects the drain electrode of nmos pass transistor 12.

Trsanscondutance amplifier 20 mainly provides voltage ratio function, but can make whole temperature sense circuit can be useful in the low-voltage running, because this trsanscondutance amplifier 20 can operate at low-down service voltage, traditional comparator configuration does not therefore coexist.As shown in Figure 3, trsanscondutance amplifier 20 is made up of following assembly: PMOS transistor 5, its source electrode obtains described Vdd voltage, grid connects described output current end, PMOS transistor 6, its source electrode also obtains described Vdd voltage, and grid also connects described output current end, a caution signal is then exported in drain electrode, PMOS transistor 7, its source electrode connects the drain electrode of PMOS transistor 5, grid connects the drain electrode of PMOS transistor 3, PMOS transistor 8, its source electrode connects the source electrode of PMOS transistor 7, grid connects the emitter-base bandgap grading of PNP bipolar transistor 9, nmos pass transistor 14, its drain electrode and grid thereof join and connect the drain electrode of PMOS transistor 7, its source electrode is ground connection then, nmos pass transistor 15, its drain electrode connects the drain electrode of PMOS transistor 8, the grid of its grid and nmos pass transistor 14 joins, source electrode then is a ground connection, nmos pass transistor 16, its drain electrode connects described caution signal, grid connects the drain electrode of nmos pass transistor 15, and source electrode is a ground connection and a not gate 10 too, its input end connects described caution signal, and output terminal then connects the grid of nmos pass transistor 13.

Get back to Fig. 2 once more, Vbe is the emitter voltage of PNP bipolar transistor 9.And Vbe and variation of temperature

Can represent by equation one:

\frac{&PartialD; Vbe}{&PartialD; T} = \frac{Vbe - (4 + m) V_{T} - Eg / q}{T}

(1)

Can calculate between temperature is for-20 ℃ to 180 ℃ by this equation,

Approximately be-2mv/ ℃.

Rnw is a N well resistance, and it has positive temperature coefficient (PTC), and the relation of its resistance and temperature can be represented by equation two:

Rnw=Rnw (27 ℃) [1+t _C1(T-27 ℃)+t _C2(T-27 ℃) ²] (two)

T wherein _C1Approximate 5m greatly, and t _C2Approximate 15 μ greatly.

Because Vnw=I * Rnw=I * Rnw (27 ℃) [1+t _C1(T-27 ℃)+t _C2(T-27 ℃) ²] (three)

Can get equation four behind the both sides differential with equation three,

If the protection temperature is set in 150 degree, via calculating

It approximately is 2mv/ ℃.Work as combination

And

Behind two functions, because And

Therefore can obtain after subtracting each other

This shows that the voltage change of each degree C is approximately 4 millivolts, is the individual numerical value that can allow general amplifier detect each degree C variation easily.Another advantage of this numerical value is to allow temperature induction unit 18 in low-down supply voltage (about 1.0 volts) running down.

If select suitable Rnw value then can be in low temperature, the voltage of Vbe can be high at Vnw, and the output of trsanscondutance amplifier 20 is to be in high-voltage state, and anti-casket this moment (inverter) is output as low-voltage state, and switch nmos pass transistor 13 is closed.When temperature raise gradually, Vbe can descend with 2 millivolts/℃ speed, and Vnw then can rise with 2 millivolts/℃ speed.In one of preferred embodiment of the present invention, if will warn temperature default as 150 ℃, then when temperature surpassed 150 ℃, Vbe can be equal to or less than Vnw, the output of trsanscondutance amplifier 20 when the time comes can switch to low-voltage, and 13 of switch nmos pass transistors are during this time opened by anti-casket 10.Because PMOS transistor 4 provides a current mirror via nmos pass transistor 11 electric current is to nmos pass transistor 12, this electric current is flowed through switch nmos pass transistor 13 and has been shared the some of the electric current that PMOS transistor 2 provided with bipolar transistor 9.Thus when caution signal transfers low-voltage state to by high-voltage state, Vbe can drop to a low voltage suddenly and improve the conducting state of PMOS transistor 8, thereby the conducting state that improves nmos pass transistor 16 is keeping the caution signal of a low-voltage state, and the output of trsanscondutance amplifier 20 can remain on low-voltage.Because Vbe voltage is an antilogarithm function (anti-log function) of bipolar transistor 9 collected currents (collector current), even if so the Vbe voltage of bipolar transistor 9 can't reduce the magnitude of current of being shared too much and change to some extent with nmos pass transistor 12.Therefore the electric current of sharing when nmos pass transistor 12 is under different supply voltages, and this characteristic provides a stable Vbe pressure drop.When temperature reduced gradually, Vnw can descend with 2 millivolts/℃ speed, and Vbe then can rise with 2 millivolts/℃ speed.Subsidiary one carries because nmos pass transistor 12 has been shared electric current, so Vbe will increase from lower Vbe voltage.Temperature must drop to certain number of degrees and come offset current to share the pressure drop that is caused.

When temperature was reduced to certain number of degrees, Vbe can be more than or equal to Vnw, and the output of trsanscondutance amplifier 20 can switch to high voltage, and this moment, nmos pass transistor 13 meetings be closed by not gate 10.After nmos pass transistor 13 is closed, nmos pass transistor 12 will no longer be shared electric current with bipolar transistor 9, so the value of Vbe can rise the value that is descended before the value that rises then approximates greatly suddenly.If so when temperature rose once again, the change in voltage that ascending temperature produced must overcome the value that Vbe rises suddenly.The control that this kind control mode has been set up the temperature door in temperature sense circuit the inside.

Fig. 4 is a test simulation result schematic diagram of the present invention, and wherein two lines are respectively Vbe and Vnw (slope of Vbe is-2 millivolts/℃, and the slope of Vnw is 2 millivolts/℃).The jump voltage of Vbe approximately is at 75 millivolts, and the control of temperature door approximately is set in 20 ℃ scope, and caution signal then can be 150 ℃ of triggerings.Can see among this figure that when low-temperature condition, the voltage height of Vbe is at Vnw voltage.But along with the rising of temperature, the voltage of Vbe can continue the to descend voltage of Vnw then can continue to rise.To about 150 ℃, Vbe is less than or equal to Vnw, this moment, caution signal can switch to low-voltage state from high-voltage state, and through not gate 10, nmos pass transistor 13 will be opened and nmos pass transistor 12 will be shared the electric current of the bipolar transistor 9 of flowing through originally and Vbe is descended suddenly.When temperature reduced gradually, the voltage of Vnw can begin to descend, and the voltage of Vbe then can go up with same speed.Since share the relation of electric current, thus will be as Vbe from lower Vbe voltage increase, and temperature must drop to certain number of degrees and come offset current to share the pressure drop that is caused.When temperature is reduced to certain number of degrees as 130 ℃, Vbe can be more than or equal to Vnw, and caution signal can switch to high-voltage state from low-voltage state, through not gate 10, nmos pass transistor 13 will be closed, because nmos pass transistor 12 is no longer shared electric current with bipolar transistor 9, so the value of Vbe can rise suddenly here at 130 ℃.If with Fig. 1, when temperature did not surpass 150 ℃, owing to there is not caution signal, so node A was high-voltage state, and B is a low-voltage state then, and the switch of nmos pass transistor 13 is a closed condition; When temperature surpassed 150 ℃, the generation of caution signal allows node A convert low-voltage state to and B becomes high-voltage state, and the switch of nmos pass transistor 13 is opened to share the electric current of the bipolar transistor 9 of partly flowing through simultaneously.

The above only is preferred embodiment of the present invention, only is illustrative for the purpose of the present invention, and nonrestrictive.Those skilled in the art is understood, and can carry out many changes to it in the spirit and scope that claim of the present invention limited, revise, even equivalence, but all will fall within the scope of protection of the present invention.

Claims

1. temperature sense circuit that is applicable to low-voltage running is characterized in that: comprise:

One temperature induction unit in order to be connected to an output current end of desiring circuit for detecting and to obtain a Vdd voltage, is come the sensor circuit temperature by voltage; This temperature induction unit comprises a plurality of PMOS transistors and PNP bipolar transistor: one the one PMOS transistor, one the 2nd PMOS transistor, one the 3rd PMOS transistor, a PNP bipolar transistor, and a positive temperature coefficient resistor; Wherein, a described PMOS transistor gate is connected an output current end with drain electrode, and source electrode then is to obtain a Vdd voltage; Described the 2nd PMOS transistor gate also connects described output current end, and source electrode also obtains described Vdd voltage; Described the 3rd PMOS transistor gate also connects described output current end, and source electrode also obtains described Vdd voltage, and drain electrode is then by described positive temperature coefficient resistor ground connection; Described PNP bipolar transistor emitter-base bandgap grading then connects then ground connection in pairs of described the 2nd PMOS transistor drain base stage and the collection utmost point, and the voltage that emitter-base bandgap grading received of described PNP bipolar transistor is a bipolar transistor emitter voltage simultaneously;

One temperature door control module in order to provide described temperature induction unit when detecting excess temperature, is guaranteed that the excess temperature caution signal starts up to temperature always to drop to certain value; Described temperature door control module comprises a plurality of nmos pass transistors of at least one PMOS transistor AND gate: one the 4th PMOS transistor, one first nmos pass transistor, one second nmos pass transistor and one the 3rd nmos pass transistor; Wherein said the 4th PMOS transistor gate connects described output current end, and source electrode obtains described Vdd voltage; Described first nmos pass transistor grid and drain electrode are connected together, and overlap with described the 4th PMOS transistor drain, and source electrode then is a ground connection; The grid of described second nmos pass transistor grid and described first nmos pass transistor joins, and source electrode also is a ground connection; Described the 3rd nmos transistor drain connects the emitter-base bandgap grading of described PNP bipolar transistor, and its source electrode then connects the drain electrode of described second nmos pass transistor; And

One trsanscondutance amplifier in order to provide voltage ratio, makes the temperature sense circuit can be applicable to the low-voltage running; Described trsanscondutance amplifier comprises a plurality of PMOS and a nmos pass transistor and a not gate: one the 5th PMOS transistor, one the 6th PMOS transistor, one the 7th PMOS transistor, one the 8th PMOS transistor, one the 4th nmos pass transistor, one the 5th nmos pass transistor, one the 6th nmos pass transistor and a not gate; Wherein, described the 5th PMOS transistor source obtains described Vdd voltage, and grid connects described output current end; Described the 6th PMOS transistor source obtains described Vdd voltage, and grid also connects described output current end, and a caution signal is then exported in drain electrode; Described the 7th PMOS transistor source connects described the 5th PMOS transistor drain, and grid connects described the 3rd PMOS transistor drain; Described the 8th PMOS transistor source connects the transistorized source electrode of described the 7th PMOS, and grid connects the emitter-base bandgap grading of described PNP bipolar transistor; Described the 4th nmos transistor drain and grid thereof join and connect described the 7th PMOS transistor drain, and its source electrode is ground connection then; Described the 5th nmos transistor drain connects described the 8th PMOS transistor drain, and the grid of its grid and described the 4th nmos pass transistor joins, and source electrode then is a ground connection; Described the 6th nmos transistor drain obtains described caution signal, and grid connects the drain electrode of described the 5th nmos pass transistor, and source electrode is ground connection too.

2. the temperature sense circuit that is applicable to the low-voltage running according to claim 1, it is characterized in that: described not gate input end obtains described caution signal, and output terminal then connects the grid of described the 3rd nmos pass transistor.

3. the temperature sense circuit that is applicable to the low-voltage running according to claim 1, it is characterized in that: described the 4th PMOS transistor is via described first nmos pass transistor, the electric current that one current mirror is provided is to described second nmos pass transistor, described the 3rd nmos pass transistor then is the switch of described current mirror, is responsible for the described current mirror of control.

4. the temperature sense circuit that is applicable to the low-voltage running according to claim 1, it is characterized in that: when described the 3rd nmos pass transistor is opened, described second nmos pass transistor can be shared electric current with the PNP bipolar transistor, if when described the 3rd nmos pass transistor was closed, described second nmos pass transistor then can stop to share electric current with the PNP bipolar transistor.