CN205427686U

CN205427686U - High accuracy excess temperature protection circuit

Info

Publication number: CN205427686U
Application number: CN201521014885.7U
Authority: CN
Inventors: 杭金华
Original assignee: SUZHOU MIX-DESIGN SEMICONDUCTOR TECHNOLOGY Co Ltd
Current assignee: SUZHOU MIX-DESIGN SEMICONDUCTOR TECHNOLOGY Co Ltd
Priority date: 2015-12-09
Filing date: 2015-12-09
Publication date: 2016-08-03
Anticipated expiration: 2025-12-09

Abstract

The utility model provides a high accuracy excess temperature protection circuit, its characterized in that: including the PTAT reference current produce circuit, excess temperature relatively voltage generation circuit, refer to voltage generation circuit, excess temperature comparator, excess temperature relatively voltage generation circuit and PTAT reference current produces the circuit and each other be the negative phase input and the non -inverting input end of excess temperature comparator, the output constitution excess temperature protection circuit of excess temperature comparator are connected respectively to the current mirror like, excess temperature comparison voltage generation circuit's output, the output of referring to voltage generation circuit output. Through relatively excess temperature comparative voltage and invariable reference voltage determine the threshold value whether temperature exceedes the temperature protection, in order to realize when production technology is too high, output excess temperature guard signal, the control product gets into the temperature guard mode, simple structure of the circuit, excess temperature protection trigger point does not receive the influence of manufacture craft, it is accurate, the uniformity is good in batches, high precision, can be used for various integrated circuit chip as excess temperature protective film piece, the MCU module, in the products such as switching power supply, it worth to have fine market development.

Description

A kind of high accuracy thermal-shutdown circuit

Technical field

This utility model belongs to semiconductor integrated circuit technical field, is specifically related to a kind of high accuracy thermal-shutdown circuit.

Background technology

Some IC products, operating temperature as to be faced in power supply, driving element etc. is too high, and caloric value is excessive, causes the most permanent problem burnt of circuit cisco unity malfunction, and this is accomplished by being integrated in circuit thermal-shutdown circuit.The effect of thermal-shutdown circuit is: be monitored circuit operating temperature, generation action after integrated circuit operation temperature reaches setting value, completes breaking circuit, closes the functions such as power supply, plays the purpose of protection circuit.

Traditional thermal-shutdown circuit is as shown in Figure 1; using threshold value is the audion of negative temperature coefficient; its operation principle is: the positive terminal voltage of comparator depends on the threshold voltage of audion; its negative terminal voltage is definite value; along with temperature raises, comparator anode input voltage reduces, when temperature constantly rises to the positive terminal voltage of comparator less than negative terminal voltage; comparator overturns, and out signal saltus step is such that it is able to go the modules such as the driving of control shutoff chip.Deviation due to production technology; the threshold value causing audion can fluctuate (shown in simulation waveform figure as shown in Figure 2); thus causing the threshold value of warm spot to be difficult to control: the temperature meeting on the low side that overheat protector triggers causes false triggering, the scope of the normal work of impact；The temperature drift that overheat protector triggers can cause overheat protector function inoperative, and the temperature triggered point precision ultimately causing overheat protector is low, and the product yield using this thermal-shutdown circuit is low.

Summary of the invention

For solving above-mentioned technical problem, the thermal-shutdown circuit that this utility model provides a kind of not to be affected by production technology, overheat protector trigger point is the highest, concordance is good, can improve the yield of product as the overheat protector of IC products.

For reaching above-mentioned purpose, the technical solution of the utility model is as follows: a kind of high accuracy thermal-shutdown circuit, it is characterized in that: include PTAT reference current generating circuit, excess temperature compares voltage generation circuit, generating circuit from reference voltage, excess temperature comparator, described excess temperature compares voltage generation circuit and PTAT reference current generating circuit current mirror each other, described excess temperature compares the outfan of voltage generation circuit, the outfan of generating circuit from reference voltage connects negative-phase input and the normal phase input end of excess temperature comparator respectively, the outfan of described excess temperature comparator constitutes the output (Out) of thermal-shutdown circuit.

In a preferred embodiment of the present utility model, farther include described excess temperature to compare voltage generation circuit and include the first PMOS, the second PMOS, the first resistance, the source electrode of described first PMOS connects power end VDD, its drain electrode connects the source electrode of the second PMOS, and the drain electrode of described second PMOS connects ground connection after the first resistance.

nullIn a preferred embodiment of the present utility model，Farther include described PTAT reference current generating circuit and include the 3rd PMOS、4th PMOS、First bipolar transistor、Second bipolar transistor、Operational amplifier、Second resistance，Described 3rd PMOS、The source electrode of both the 4th PMOS is all connected with power end VDD，Both grids all grids with the first PMOS are connected，The drain electrode of described 3rd PMOS connects the second resistance、And both junction points form node A，The other end of described second resistance connects ground connection after the first bipolar transistor，The drain electrode of described 4th PMOS connects ground connection after the second bipolar transistor，4th PMOS forms node B with the junction point of the second bipolar transistor，Node A、The normal phase input end of node B concatenation operation amplifier respectively and negative-phase input，The outfan of described operational amplifier connects the grid of the 3rd PMOS.

In a preferred embodiment of the present utility model, farther include described PTAT reference current generating circuit and also include the 5th PMOS, 6th PMOS, described 5th PMOS, the grid of both the 6th PMOS all grids with the second PMOS are connected, described 5th PMOS is connected between the 3rd PMOS and the second resistance, its source electrode connects the drain electrode of the 3rd PMOS, its drain electrode connects the second resistance, described 6th PMOS is connected between the 4th PMOS and the second bipolar transistor, its source electrode connects the drain electrode of the 4th PMOS, its drain electrode connects the second bipolar transistor.

In a preferred embodiment of the present utility model, farther include described first bipolar transistor and the second bipolar transistor is bipolar npn transistor npn npn, the base stage of described first bipolar transistor is connected with its colelctor electrode, connect after be connected with the second resistance, its grounded emitter, the base stage of described second bipolar transistor is connected with its colelctor electrode, connect after be connected with the drain electrode of the 6th PMOS, its grounded emitter.

In a preferred embodiment of the present utility model, farther include described first bipolar transistor and the second bipolar transistor is positive-negative-positive bipolar transistor, the base stage of described first bipolar transistor be connected with its colelctor electrode after ground connection, its emitter stage connects the second resistance, the base stage of described second bipolar transistor be connected with its colelctor electrode after ground connection, its emitter stage connect the 6th PMOS drain electrode.

nullIn a preferred embodiment of the present utility model，Farther include described PTAT reference current generating circuit and include the 7th PMOS、8th PMOS、First NMOS tube、Second NMOS tube、3rd bipolar transistor、4th bipolar transistor、3rd resistance，Described 7th PMOS、The source electrode of both the 8th PMOS is all connected with power end VDD，Both grids are all connected with the grid of the first PMOS，Described first NMOS tube、The grid of both the second NMOS tube connects，The grid of the first NMOS tube drains with it and is connected，The drain electrode of described 7th PMOS connects the drain electrode of the first NMOS tube，The source electrode of described first NMOS tube connects the 3rd resistance，The other end of described 3rd resistance connects ground connection after the 3rd bipolar transistor，The drain electrode of described 8th PMOS connects the drain electrode of the second NMOS tube，The source electrode of described second NMOS tube connects ground connection after the 4th bipolar transistor.

In a preferred embodiment of the present utility model, farther include described PTAT reference current generating circuit and also include the 9th PMOS, the tenth PMOS, both grids are all connected with the grid of the second PMOS, described 9th PMOS is connected between the 7th PMOS and the first NMOS tube, the source electrode of the 9th PMOS and drain electrode connect drain electrode and the drain electrode of the first NMOS tube of the 7th PMOS respectively, tenth PMOS is connected between the 8th PMOS and the second NMOS tube, and the source electrode of the tenth PMOS and drain electrode connect drain electrode and the drain electrode of the second NMOS tube of the 8th PMOS respectively.

In a preferred embodiment of the present utility model, farther include described 3rd bipolar transistor and the 4th bipolar transistor is bipolar npn transistor npn npn, it is connected with the 3rd resistance after the base stage of described 3rd bipolar transistor and the connection of its colelctor electrode, connection, its grounded emitter, it is connected with the source electrode of the second NMOS tube after the base stage of described 4th bipolar transistor and the connection of its colelctor electrode, connection, its grounded emitter.

In a preferred embodiment of the present utility model, farther include described 3rd bipolar transistor and the 4th bipolar transistor is positive-negative-positive bipolar transistor, the base stage of described 3rd bipolar transistor and its colelctor electrode connect, connect after ground connection, its emitter stage connects the 3rd resistance, the base stage of described 4th bipolar transistor and its colelctor electrode connect, connect after ground connection, its emitter stage connects the source electrode of the second NMOS tube.

The beneficial effects of the utility model are: compared with prior art, thermal-shutdown circuit of the present utility model obtains the reference current raised and raise with temperature by PTAT reference current generating circuit, compare with the excess temperature of PTAT reference current generating circuit current mirror each other that reference current is become not raised with temperature by technogenic influence and voltage by voltage generation circuit and the excess temperature that raises compares voltage, compare voltage by excess temperature and judge whether temperature exceedes the threshold value of temperature protection with constant reference voltage, to realize when product temperature is too high, output overheat protector signal, control product and enter temperature protection state.Circuit structure of the present utility model is simple; overheat protector trigger point is not affected by processing technology; accurately, concordance is good in batches, precision is high, can have good market development and be worth as overheat protector module in the products such as various IC chips, MCM module, Switching Power Supply.

Accompanying drawing explanation

In order to be illustrated more clearly that the technical scheme in this utility model embodiment technology, in describing embodiment technology below, the required accompanying drawing used is briefly described, apparently, accompanying drawing in describing below is only embodiments more of the present utility model, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the schematic diagram of the thermal-shutdown circuit of prior art；

Fig. 2 is the simulation waveform figure of the thermal-shutdown circuit of prior art；

Fig. 3 is the circuit theory diagrams of this utility model preferred embodiment；

Fig. 4 is the circuit theory diagrams of this utility model the second embodiment；

Fig. 5 is the circuit theory diagrams of this utility model the 3rd embodiment；

Fig. 6 is the circuit theory diagrams of this utility model the 4th embodiment；

Fig. 7 is the simulation waveform figure of this utility model preferred embodiment.

Wherein, 10-PTAT reference current generating circuit, 20-excess temperature compares voltage generation circuit, 30-generating circuit from reference voltage.

Detailed description of the invention

Below in conjunction with the accompanying drawing in this utility model embodiment, the technical scheme in this utility model embodiment is clearly and completely described, it is clear that described embodiment is only a part of embodiment of this utility model rather than whole embodiments.Based on the embodiment in this utility model, the every other embodiment that those of ordinary skill in the art are obtained under not making creative work premise, broadly fall into the scope of this utility model protection.

Embodiment one

As shown in Figure 3, the present embodiment discloses a kind of high accuracy thermal-shutdown circuit, including PTAT reference current generating circuit 10, excess temperature compares voltage generation circuit 20, generating circuit from reference voltage 30, excess temperature comparator U1, described excess temperature compares voltage generation circuit 20 and PTAT reference current generating circuit 10 current mirror each other, described excess temperature compares the outfan of voltage generation circuit 20, the outfan of generating circuit from reference voltage 30 connect respectively excess temperature comparator U1 negative-phase input (-) and normal phase input end (+), the outfan of described excess temperature comparator U1 constitutes the output Out of thermal-shutdown circuit.PTAT reference current generating circuit 10 of the present utility model is not affected by processing technology for obtaining, the reference current raised with temperature and raise, excess temperature compares voltage generation circuit 20 and compares voltage for the reference current of acquisition is changed into excess temperature, generating circuit from reference voltage 30 is used for obtaining reference voltage Vref accurately, excess temperature comparator U1 compares the size of voltage and reference voltage Vref and judges whether temperature exceedes the threshold value of temperature protection by comparing excess temperature, when beyond temperature protection threshold value, the outfan Out of excess temperature comparator U1 exports overheat protector signal, control product and enter temperature protection state.

Concrete, described excess temperature compares voltage generation circuit 20 and includes the first PMOS PM1, the second PMOS PM2, the first resistance R1, the source electrode of described first PMOS PM1 connects power end VDD, its drain electrode connects the source electrode of the second PMOS PM2, and the drain electrode of described second PMOS PM2 connects ground connection after the first resistance R1.

nullAs preferred embodiment of the present utility model，Described PTAT reference current generating circuit 10 includes the 3rd PMOS PM3、4th PMOS PM4、5th PMOS PM5、6th PMOS PM6、First bipolar transistor Q1、Second bipolar transistor Q2、Operational amplifier U2、Second resistance R2，Described 3rd PMOS PM3、The source electrode of both the 4th PMOS PM4 is all connected with power end VDD，Both grids all grids with the first PMOS PM1 are connected，Described 5th PMOS PM5、The grid of both the 6th PMOS PM6 all grids with the second PMOS PM2 are connected，The drain electrode of described 3rd PMOS PM3 connects the source electrode of the 5th PMOS PM5，The drain electrode of the 5th PMOS PM5 connects the second resistance R2，Junction point forms node A，The other end of the second resistance R2 connects ground connection after the first bipolar transistor Q1，The drain electrode of the 4th PMOS PM4 connects the source electrode of the 6th PMOS PM6，Junction point forms the drain electrode of node B the 6th PMOS PM6 and connects ground connection after the second bipolar transistor Q2，Node A、The normal phase input end of node B concatenation operation amplifier U2 respectively and negative-phase input，The outfan of described operational amplifier U2 connects the grid of the 3rd PMOS PM3.

Concrete, described first bipolar transistor Q1 and the second bipolar transistor Q2 is bipolar npn transistor npn npn, the base stage of described first bipolar transistor Q1 is connected with its colelctor electrode, connect after be connected with the second resistance R2, its grounded emitter, the base stage of described second bipolar transistor Q2 is connected with its colelctor electrode, connect after be connected with the drain electrode of the 6th PMOS PM6, its grounded emitter.

In order to mate, it is thus achieved that better performance, the first bipolar transistor Q1 uses the coupled in parallel of M same size, and Q2 uses the transistor of a same size.

In order to mate, resistance R1 and resistance R2 uses identical resistance type, and uses the coupling technique of painting on domain.

Based on foregoing circuit structure, its circuit theory is as follows: be current mirror based on PTAT reference current generating circuit 10, voltage on node A and node B 2 is identical, pressure drop on second resistance R2 is equal to the difference of the BE knot on the second bipolar transistor Q2 and two transistors of the first bipolar transistor Q1, i.e. V_R2=V_BE2-V_BE1,

C-V characteristic formula I according to PN junction_D=I_S·(e^V/VT-1) V is released_BE1=VT*ln (I1/M I_S),V_BE2=VT*ln (I2/I_S), wherein M is the number of the first bipolar transistor Q1 parallel transistor,

V_R2=V_BE2-V_BE1

=VT*ln (I2/I_S)-VT*ln(I1/M·I_S)

=VT*lnM,

Electric current on second resistance R2

I_R2=V_R2/R2

=(VT*lnM)/R2, VT=KT/q, T are absolute temperature, and q is electron charge, and k is Boltzmann constant, and q, k, M are not constant by transistor fabrication process influence of fluctuations, therefore, I_R2For not by transistor fabrication process influence of fluctuations and the variable that increases along with the rising of temperature.

Voltage generation circuit 20 and PTAT reference current generating circuit 10 current mirror each other, therefore the electric current I on the first resistance R1 is compared based on excess temperature_R1With the electric current I on the second resistance R2_R2, i.e. I_R1=I_R2=(VT*lnM)/R2, the voltage on the first resistance R1

V_R1=I_R1*R1

=[R1* (VT*lnM)]/R2, the first resistance R1 and the second same type of resistance R2, and matching is good, so V_R1For not by transistor fabrication process influence of fluctuations and the variable that increases with the rising of temperature, the voltage V on the first resistance R1_R1It is the voltage of excess temperature comparator U1 negative phase end；The voltage of excess temperature comparator U1 positive terminal is the reference voltage Vref of generating circuit from reference voltage 30 output simultaneously, and reference voltage Vref is voltage reference signal common in chip, zero temp shift, the most accurate, precision, within ± 1%, is not affected by temperature and technological fluctuation, makes V when temperature raises_R1> Vref time, excess temperature comparator U1 output switching activity, trigger overheat protector.Compare the voltage of input and the most do not fluctuated by transistor fabrication process owing to constituting excess temperature comparator U1 two and affected, the control signal that excess temperature comparator U1 is exported is not fluctuated by transistor fabrication process and is affected, the precision of excess temperature trigger point is high, concordance is good in batches, is illustrated in figure 7 the simulation waveform figure of this utility model preferred embodiment.

Separately, constitute excess temperature and compare the first PMOS PM1 and second PMOS PM2 of voltage generation circuit 20 current mirror, in the case of not considering PSRR, only first PMOS PM1 just can realize operation principle of the present utility model, the increase of the second PMOS PM2 can improve PSRR, and the fluctuation reducing power end Vdd brings impact to circuit.

Separately, constitute two current mirror loops of PTAT reference current generating circuit 10, the the first current mirror loop being i.e. made up of the 3rd PMOS PM3, the 5th PMOS PM5, the the second current mirror loop being made up of the 4th PMOS PM4, the 6th PMOS PM6, in the case of not considering PSRR, in first current mirror loop, the only the 3rd PMOS PM3 just can realize operation principle of the present utility model, the increase of the 5th PMOS PM5 can improve PSRR, and the fluctuation reducing power end Vdd brings impact to circuit；In the case of not considering PSRR, in second current mirror loop, the only the 4th PMOS PM4 just can realize operation principle of the present utility model, the increase of the 6th PMOS PM6 can improve PSRR, and the fluctuation reducing power end Vdd brings impact to circuit.

Embodiment two

Embodiment two as shown in Figure 4 differs only in from embodiment one: the type selecting of two bipolar transistors (Q1, Q2) is different, it is positive-negative-positive bipolar transistor, wherein, the base stage of described first bipolar transistor Q1 be connected with its colelctor electrode after ground connection, its emitter stage connects the second resistance R2, the base stage of described second bipolar transistor Q2 be connected with its colelctor electrode after ground connection, its emitter stage connect the 6th PMOS PM6 drain electrode.Operation principle with embodiment one, achieves the excess temperature of the overheat protector point that gets an electric shock equally and is not fluctuated by transistor fabrication process and affected, excess temperature trigger point precision is high, in batches concordance good.

Embodiment three

nullEmbodiment three as shown in Figure 5 is from the difference of embodiment one: the structure of PTAT reference current generating circuit 10 is different: described PTAT reference current generating circuit 10 includes the 7th PMOS PM7、8th PMOS PM8、9th PMOS PM9、Tenth PMOS PM10、First NMOS tube NM1、Second NMOS tube NM2、3rd bipolar transistor Q3、4th bipolar transistor Q4、3rd resistance R3，Described 7th PMOS PM7、The source electrode of both the 8th PMOS PM8 is all connected with power end VDD，Both grids are all connected with the grid of the first PMOS PM1，Described 9th PMOS PM9、The grid of both the tenth PMOS PM10 is all connected with the grid of the second PMOS PM2，Described first NMOS tube NM1、The grid of both the second NMOS tube NM2 connects，The grid of the first NMOS tube NM1 drains with it and is connected，7th PMOS PM7、The drain electrode of both the 8th PMOS PM8 connects the 9th PMOS PM9 respectively、The source electrode of the tenth PMOS PM10，Described 9th PMOS PM9、The drain electrode of the tenth PMOS PM10 connects the first NMOS tube NM1 respectively、The drain electrode of the second NMOS tube NM2，The source electrode of described first NMOS tube NM1 connects the 3rd resistance R3，The other end of described 3rd resistance R3 connects ground connection after the 3rd bipolar transistor Q3，The source electrode of described second NMOS tube NM2 connects ground connection after the 4th bipolar transistor Q4.Wherein, the source electrode of the first NMOS tube NM1 and the junction point of the 3rd resistance R3 form node A, and the source electrode of the second NMOS tube NM2 and the junction point of the 4th bipolar transistor Q4 form node B.

Concrete, described 3rd bipolar transistor Q3 and the 4th bipolar transistor Q4 is bipolar npn transistor npn npn, it is connected with the 3rd resistance R3 after the base stage of described 3rd bipolar transistor Q3 and the connection of its colelctor electrode, connection, its grounded emitter, it is connected with the source electrode of the second NMOS tube NM2 after the base stage of described 4th bipolar transistor Q4 and the connection of its colelctor electrode, connection, its grounded emitter.

In order to mate, it is thus achieved that better performance, the 3rd bipolar transistor Q3 can use the coupled in parallel of M same model.

Based on foregoing circuit structure, its circuit theory is as follows: be current mirror based on PTAT reference current generating circuit 10, voltage on node A and node B 2 is identical, pressure drop on 3rd resistance R3 is equal to the difference of the BE knot on the 4th bipolar transistor Q4 and two transistors of the 3rd bipolar transistor Q3, i.e. V_R3=V_BE4-V_BE3,

C-V characteristic formula I according to PN junction_D=I_S·(e^V/VT-1) V is released_BE3=VT*ln (I3/M I_S),V_BE4=VT*ln (I4/I_S), wherein M is the number of the first bipolar transistor Q1 parallel transistor,

V_R3=V_BE4-V_BE3

=VT*ln (I4/I_S)-VT*ln(I3/M·I_S)

=VT*lnM,

Electric current on 3rd resistance R3

I_R3=V_R3/R3

=(VT*lnM)/R3, VT=KT/q, T are absolute temperature, and q is electron charge, and k is Boltzmann constant, and q, k, M are not constant by transistor fabrication process influence of fluctuations, therefore, I_R2For not by transistor fabrication process influence of fluctuations and the variable that increases along with the rising of temperature.

Compare voltage generation circuit 20 and PTAT reference current generating circuit 10 current mirror each other, the first resistance R1 and the 3rd same type of resistance R3 based on excess temperature, and matching is good, the therefore electric current I on the first resistance R1_R1With the electric current I on the 3rd resistance R3_R3, i.e. I_R1=I_R3=(VT*lnM)/R3, the voltage on the first resistance R1

V_R1=I_R1*R1

=[R1* (VT*lnM)]/R3, for by transistor fabrication process influence of fluctuations and the variable that increases with the rising of temperature, the voltage V on the first resistance R1_R1It is the voltage of excess temperature comparator U1 negative phase end；The voltage of excess temperature comparator U1 positive terminal is the reference voltage Vref of generating circuit from reference voltage 30 output simultaneously, and reference voltage Vref is voltage reference signal common in chip, zero temp shift, the most accurate, precision+-1% within, do not affected by temperature and technological fluctuation, when temperature raise make V_R1> Vref time, excess temperature comparator U1 output switching activity, trigger overheat protector.Compare the voltage of input and the most do not fluctuated by transistor fabrication process owing to constituting excess temperature comparator U1 two and affected, the control signal that excess temperature comparator U1 is exported is not fluctuated by transistor fabrication process and is affected, the precision of excess temperature trigger point is high, and concordance is good in batches.

Separately, constitute two current mirror loops of PTAT reference current generating circuit 10, the the first current mirror loop being i.e. made up of the 7th PMOS PM7, the 9th PMOS PM9, the the second current mirror loop being made up of the 8th PMOS PM8, the tenth PMOS PM10, in the case of not considering PSRR, in first current mirror loop, the only the 7th PMOS PM7 just can realize operation principle of the present utility model, the increase of the 9th PMOS PM9 can improve PSRR, and the fluctuation reducing power end Vdd brings impact to circuit；In the case of not considering PSRR, in second current mirror loop, the only the 8th PMOS PM8 just can realize operation principle of the present utility model, the increase of the tenth PMOS PM10 can improve PSRR, and the fluctuation reducing power end Vdd brings impact to circuit.

Embodiment four

Embodiment four as shown in Figure 6 differs only in from embodiment three: the type selecting of two bipolar transistors (Q3, Q4) is different, it is positive-negative-positive bipolar transistor, wherein, described 3rd bipolar transistor Q3 and the 4th bipolar transistor Q4 is positive-negative-positive bipolar transistor, the base stage of described 3rd bipolar transistor Q3 and its colelctor electrode connect, connect after ground connection, its emitter stage connects the 3rd resistance R3, the base stage of described 4th bipolar transistor Q4 and its colelctor electrode connect, connect after ground connection, its emitter stage connects the source electrode of the second NMOS tube NM2.Operation principle with embodiment one, achieves the excess temperature of the overheat protector point that gets an electric shock equally and is not fluctuated by transistor fabrication process and affected, excess temperature trigger point precision is high, in batches concordance good.

Described above to the disclosed embodiments, makes professional and technical personnel in the field be capable of or uses this utility model.Multiple amendment to these embodiments will be apparent from for those skilled in the art, and generic principles defined herein can realize in the case of without departing from spirit or scope of the present utility model in other embodiments.Therefore, this utility model is not intended to be limited to the embodiments shown herein, and is to fit to the widest scope consistent with principles disclosed herein and features of novelty.

Claims

1. a high accuracy thermal-shutdown circuit; it is characterized in that: include that PTAT reference current generating circuit, excess temperature compare voltage generation circuit, generating circuit from reference voltage, excess temperature comparator; described excess temperature compares voltage generation circuit and PTAT reference current generating circuit current mirror each other; described excess temperature compares the outfan of voltage generation circuit, the outfan of generating circuit from reference voltage connects negative-phase input and the normal phase input end of excess temperature comparator respectively, and the outfan of described excess temperature comparator constitutes the output (Out) of thermal-shutdown circuit.

A kind of high accuracy thermal-shutdown circuit the most according to claim 1; it is characterized in that: described excess temperature compares voltage generation circuit and includes the first PMOS, the second PMOS, the first resistance; the source electrode of described first PMOS connects power end VDD; its drain electrode connects the source electrode of the second PMOS, and the drain electrode of described second PMOS connects ground connection after the first resistance.

nullA kind of high accuracy thermal-shutdown circuit the most according to claim 2，It is characterized in that: described PTAT reference current generating circuit includes the 3rd PMOS、4th PMOS、First bipolar transistor、Second bipolar transistor、Operational amplifier、Second resistance，Described 3rd PMOS、The source electrode of both the 4th PMOS is all connected with power end VDD，Both grids all grids with the first PMOS are connected，The drain electrode of described 3rd PMOS connects the second resistance、And both junction points form node A，The other end of described second resistance connects ground connection after the first bipolar transistor，The drain electrode of described 4th PMOS connects ground connection after the second bipolar transistor，4th PMOS forms node B with the junction point of the second bipolar transistor，Node A、The normal phase input end of node B concatenation operation amplifier respectively and negative-phase input，The outfan of described operational amplifier connects the grid of the 3rd PMOS.

A kind of high accuracy thermal-shutdown circuit the most according to claim 3, it is characterized in that: described PTAT reference current generating circuit also includes the 5th PMOS, 6th PMOS, described 5th PMOS, the grid of both the 6th PMOS all grids with the second PMOS are connected, described 5th PMOS is connected between the 3rd PMOS and the second resistance, its source electrode connects the drain electrode of the 3rd PMOS, its drain electrode connects the second resistance, described 6th PMOS is connected between the 4th PMOS and the second bipolar transistor, its source electrode connects the drain electrode of the 4th PMOS, its drain electrode connects the second bipolar transistor.

A kind of high accuracy thermal-shutdown circuit the most according to claim 4; it is characterized in that: described first bipolar transistor and the second bipolar transistor are bipolar npn transistor npn npn; the base stage of described first bipolar transistor is connected with its colelctor electrode, connect after be connected with the second resistance; its grounded emitter; the base stage of described second bipolar transistor is connected with its colelctor electrode, connect after be connected with the drain electrode of the 6th PMOS, its grounded emitter.

A kind of high accuracy thermal-shutdown circuit the most according to claim 4; it is characterized in that: described first bipolar transistor and the second bipolar transistor are positive-negative-positive bipolar transistor; the base stage of described first bipolar transistor be connected with its colelctor electrode after ground connection; its emitter stage connects the second resistance; the base stage of described second bipolar transistor be connected with its colelctor electrode after ground connection, its emitter stage connect the 6th PMOS drain electrode.

nullA kind of high accuracy thermal-shutdown circuit the most according to claim 2，It is characterized in that: described PTAT reference current generating circuit includes the 7th PMOS、8th PMOS、First NMOS tube、Second NMOS tube、3rd bipolar transistor、4th bipolar transistor、3rd resistance，Described 7th PMOS、The source electrode of both the 8th PMOS is all connected with power end VDD，Both grids are all connected with the grid of the first PMOS，Described first NMOS tube、The grid of both the second NMOS tube connects，The grid of the first NMOS tube drains with it and is connected，The drain electrode of described 7th PMOS connects the drain electrode of the first NMOS tube，The source electrode of described first NMOS tube connects the 3rd resistance，The other end of described 3rd resistance connects ground connection after the 3rd bipolar transistor，The drain electrode of described 8th PMOS connects the drain electrode of the second NMOS tube，The source electrode of described second NMOS tube connects ground connection after the 4th bipolar transistor.

A kind of high accuracy thermal-shutdown circuit the most according to claim 7, it is characterized in that: described PTAT reference current generating circuit also includes the 9th PMOS, tenth PMOS, both grids are all connected with the grid of the second PMOS, described 9th PMOS is connected between the 7th PMOS and the first NMOS tube, the source electrode of the 9th PMOS and drain electrode connect drain electrode and the drain electrode of the first NMOS tube of the 7th PMOS respectively, tenth PMOS is connected between the 8th PMOS and the second NMOS tube, the source electrode of the tenth PMOS and drain electrode connect drain electrode and the drain electrode of the second NMOS tube of the 8th PMOS respectively.

A kind of high accuracy thermal-shutdown circuit the most according to claim 8; it is characterized in that: described 3rd bipolar transistor and the 4th bipolar transistor are bipolar npn transistor npn npn; it is connected with the 3rd resistance after the base stage of described 3rd bipolar transistor and the connection of its colelctor electrode, connection; its grounded emitter; it is connected with the source electrode of the second NMOS tube after the base stage of described 4th bipolar transistor and the connection of its colelctor electrode, connection, its grounded emitter.

A kind of high accuracy thermal-shutdown circuit the most according to claim 8; it is characterized in that: described 3rd bipolar transistor and the 4th bipolar transistor are positive-negative-positive bipolar transistor; the base stage of described 3rd bipolar transistor and its colelctor electrode connect, connect after ground connection; its emitter stage connects the 3rd resistance; the base stage of described 4th bipolar transistor and its colelctor electrode connect, connect after ground connection, its emitter stage connects the source electrode of the second NMOS tube.