CN205405320U - Band stop resists tub reference circuit of adjusting that exhausts - Google Patents

Abstract

The utility model provides a band stop resists tub reference circuit of adjusting that exhausts includes at least: mains voltage's depletion type NMOS pipe is connected to the drain terminal, the source end of depletion type NMOS pipe links to each other with the first end of impedance, the bars end of depletion type NMOS pipe with the second end of impedance links to each other, the enhancement mode NMOS pipe on source termination ground, the bars end of enhancement mode NMOS pipe with the drain terminal of enhancement mode NMOS pipe link to each other the back with the second end of impedance links to each other, the drain terminal of enhancement mode NMOS pipe is the output. The utility model discloses a reference voltage of band stop resists tub reference circuit of adjusting that exhausts output is temperature independent, and is irrelevant with mains voltage, occupies simultaneously that the domain area is little, the technology dependence is little, the precision is easily controlled, is suitable for actual production and use.

Description

A kind of with impedance regulate exhaust pipe reference circuit

Technical field

This utility model relates to semiconductor applications, particularly relate to a kind of with impedance regulate exhaust pipe reference circuit.

Background technology

Reference voltage source or reference voltage typically refer to the high stability voltage source making voltage reference in circuit.Along with the continuous increase of footprint, the especially development of system integration technology (SOC), it also becomes on a large scale, indispensable basic circuit module in super large-scale integration and nearly all digital simulator system.

In the process that analogue signal and digital signal are changed mutually, reference voltage chip plays very important effect, and the quantization work that it is analogue signal provides standard.In many integrated circuits and circuit unit, such as digital to analog converter (DAC), analog-digital converter (ADC), linear voltage regulator and switching regulator, it is required for accurate and stable voltage reference.In digital to analog converter, DAC, according to the digital input signals presented on its input terminals, selects from DC reference voltage and produces simulation output；In analog-digital converter, D/C voltage benchmark is used for again producing digitized output signal together with analog input signal.Precision measuring instrument instruments and meters and wide variety of digital communication system are all often used as systematic survey and school reference of reference reference voltage source.Therefore, reference voltage source occupies critically important status in Analogous Integrated Electronic Circuits, and it directly affects performance and the precision of electronic system.

It is illustrated in figure 1 tradition and exhausts enhancement mode reference circuit, including depletion type NMOS tube 101, enhancement mode NMOS tube 102, the drain terminal of depletion type NMOS tube 101 connects the drain terminal of link enhancement type NMOS tube 102 after supply voltage, grid end are connected with source, and the grid end of enhancement mode NMOS tube 102 is connected with its drain terminal, source ground connection；Depletion type NMOS tube 101 is connected into current source form and provides current offset to enhancement mode NMOS tube 102, and the source of depletion type NMOS tube 101 and the drain terminal of enhancement mode NMOS tube 102 are final reference output.Following relation is had according to circuit structure:

$I_{D101}=\frac{1}{2}{K}_{101}{(0+V_D)}^2---\left(1\right)$

$I_{D102}=\frac{1}{2}{K}_{102}{(VREF-V_T)}^2---\left(2\right)$

I_D101=I_D102(3)

Can be obtained by relation above: $VREF=\frac{\sqrt{K_{101}}}{\sqrt{K_{102}}}{V}_D+V_T---\left(4\right)$

Wherein, V_DFor the absolute value of the threshold voltage of depletion type NMOS tube, there is positive temperature characterisitic；V_TFor the threshold voltage of enhancement mode NMOS tube, have for negative temperature characteristic；I_D101Drain terminal electric current for depletion type NMOS tube；I_D102Drain terminal electric current for enhancement mode NMOS tube；K₁₀₁Breadth length ratio for depletion type NMOS tube；K₁₀₂Breadth length ratio for enhancement mode NMOS tube；VREF is the reference voltage of output.

When depletion type NMOS tube 101 and enhancement mode NMOS tube 102 select suitable breadth length ratio, VREF can be made to obtain voltage (example: the K of zero-temperature coefficient characteristic₁₀₁=2 μ/120 μ, K₁₀₂=2 μ/50 μ, certain factory 0.5 μ technique corresponding)；In same up-to-date style (4), VREF is a voltage unrelated with supply voltage (VDD).To sum up when selecting suitable breadth length ratio that VREF can be made to realize not with the basis reference voltage of voltage and variations in temperature.

But for the current relationship of depletion type NMOS tube, formula (1) is only at the drain terminal electric current I of depletion type NMOS tube_D101It is only more accurate time smaller, if I_D101Relatively larger, formula (1) may require that, one factor relevant with input voltage of addition is revised, so may result in final VREF is the function relevant with input voltage, thus can not accurately realize the reference voltage source that voltage is unrelated；So when being typically in practical application, I_D101A smaller value can be taken, thus cause K₁₀₁Take a smaller value, a pipe that width-length ratio is very big generally all can be adopted to realize, simultaneously in order to ensure zero-temperature coefficient characteristic, K₁₀₂Also taking smaller value, final depletion type NMOS tube 101 and enhancement mode NMOS tube 102 will adopt down the pipe that width-length ratio is very big, so cause that the chip area of the two pipe is very big.

Additionally, exhaust Guan Eryan for existing, adopt this structure to realize reference voltage source and also have one to compare stubborn problem, V_DIn art production process, the precision of this value is difficult to control, and causes V_DScope with technological fluctuation is very wide.

Therefore, how improving existing reference circuit structure, reduction chip area, raising precision have become one of those skilled in the art's problem demanding prompt solution.

Utility model content

The shortcoming of prior art in view of the above, the purpose of this utility model is in that providing a kind of exhausts pipe reference circuit with what impedance regulated, for solving metal-oxide-semiconductor in prior art, to take chip area big, and the voltage with positive temperature coefficient is big with technological fluctuation, precision is difficult to the problems such as control.

For achieving the above object and other relevant purposes, this utility model provides a kind of and exhausts pipe reference circuit with what impedance regulated, and the described pipe reference circuit that exhausts regulated with impedance at least includes:

Drain terminal connects the depletion type NMOS tube of supply voltage, and the source of described depletion type NMOS tube is connected with the first end of impedance, and the grid end of described depletion type NMOS tube is connected with the second end of described impedance；The enhancement mode NMOS tube of source ground connection, the grid end of described enhancement mode NMOS tube is connected with the second end of described impedance after being connected with the drain terminal of described enhancement mode NMOS tube, and the drain terminal of described enhancement mode NMOS tube is outfan.

Preferably, described impedance is the resistance that resistance is fixing.

Preferably, described impedance includes a resistance string, each resistance two ends parallel connection fuse, and each fuse two ends connect pad, controls fuse by pad and blows or do not blow and adjust resistance value with this.

Exhaust pipe reference circuit as it has been described above, of the present utility model with what impedance regulated, have the advantages that

The reference voltage exhausting the output of pipe reference circuit regulated with impedance of the present utility model is temperature independent, unrelated with supply voltage, takies that chip area is little, technique dependency is little, precision is easy to control simultaneously, is suitable to actual production and use.

Accompanying drawing explanation

Fig. 1 is shown as of the prior art and exhausts enhancement mode reference circuit schematic diagram.

Fig. 2 is shown as a kind of embodiment exhausting pipe reference circuit regulated with impedance of the present utility model.

Fig. 3 is shown as the another embodiment exhausting pipe reference circuit regulated with impedance of the present utility model.

Element numbers explanation

101 depletion type NMOS tube

102 enhancement mode NMOS tube

103 depletion type NMOS tube

104 impedances

105 enhancement mode NMOS tube

106 first resistance

107 second resistance

108 the 3rd resistance

Detailed description of the invention

Below by way of specific instantiation, embodiment of the present utility model being described, those skilled in the art the content disclosed by this specification can understand other advantages of the present utility model and effect easily.This utility model can also be carried out by additionally different detailed description of the invention or apply, and the every details in this specification based on different viewpoints and application, can also carry out various modification or change under without departing from spirit of the present utility model.

Refer to Fig. 2～Fig. 3.It should be noted that, the diagram provided in the present embodiment only illustrates basic conception of the present utility model in a schematic way, then assembly that in graphic, only display is relevant with this utility model but not component count when implementing according to reality, shape and size drafting, during its actual enforcement, the kenel of each assembly, quantity and ratio can be a kind of random change, and its assembly layout kenel is likely to increasingly complex.

Embodiment one

As in figure 2 it is shown, this utility model provides a kind of exhausts pipe reference circuit with what impedance regulated, the described pipe reference circuit that exhausts with impedance adjustment at least includes:

Drain terminal connects the depletion type NMOS tube 103 of supply voltage VDD, and the source of described depletion type NMOS tube 103 is connected with the first end of impedance, and the grid end of described depletion type NMOS tube 103 is connected with the second end of described impedance；The enhancement mode NMOS tube 105 of source ground connection, the grid end of described enhancement mode NMOS tube 105 is connected with the second end of described impedance after being connected with the drain terminal of described enhancement mode NMOS tube 105, and the drain terminal of described enhancement mode NMOS tube 105 is outfan, output reference voltage VREF.

Described impedance 104 can be the device that electric current arbitrarily rises inhibition, does not repeat one by one at this.In the present embodiment, the resistance that described impedance 104 is fixed for resistance.

Following relation is had according to circuit structure:

$I_{D103}=\frac{1}{2}{K}_{103}{(-I_{D103}*Z+V_D)}^2---\left(4\right)$

$I_{D105}=\frac{1}{2}{K}_{105}{(VREF-V_T)}^2---\left(5\right)$

Obtained by relation above: $I_{D103}=\frac{V_D}{Z}+\frac{1}{K_{103}{Z}^2}-2\sqrt{\frac{2{\mathrm{ZV}}_D}{K_{103}}+\frac{1}{K_{103}^2}}---\left(6\right)$

$VREF=V_T+\sqrt{\frac{2V_D}{K_{105}*Z}+\frac{2}{K_{103}*K_{105}*Z^2}-\frac{4}{K_{105}}\sqrt{\frac{2V_D*Z}{K_{103}}+\frac{1}{K_{103}^2}}}---\left(7\right)$

Wherein, I_D103For the drain terminal electric current of depletion type NMOS tube 103, I_D105For the drain terminal electric current of enhancement mode NMOS tube 105, V_TFor the threshold voltage of described enhancement mode NMOS tube 105, V_DFor the absolute value of the threshold voltage of described depletion type NMOS tube 103, K₁₀₅For the breadth length ratio of described enhancement mode NMOS tube 105, K₁₀₃For the breadth length ratio of described depletion type NMOS tube 103, Z is the resistance value of described impedance 104.

According to formula (7), utilize the threshold voltage V of described depletion type NMOS tube 103_DPositive temperature characterisitic and the threshold voltage V of described enhancement mode NMOS tube 105_TThe compensation of negative temperature characteristic.First affect Xiang Lixian in positive temperature and ignore the item that impact is lessThe item unrelated with temperatureRetain the item that temperature impact is relatively largerThreshold voltage V according to described depletion type NMOS tube 103_DPositive temperature characterisitic and the threshold voltage V of described enhancement mode NMOS tube 105_TNegative temperature characteristic (this with adopt technique relevant), first determine K₁₀₅* the value of Z；Then final suitable K is determined further according to the current requirements convolution (4) required by circuit and formula (5)₁₀₃、K₁₀₅And Z；So ensure that reference voltage V REF realizes temperature independence.And reference voltage V REF and supply voltage VDD is uncorrelated in formula (7), therefore this circuit can also realize power supply and the unrelated benchmark of temperature.

Contrast (1) and formula (6), tradition exhausts the drain terminal electric current I of depletion type NMOS tube in enhancement mode reference circuit_D101It is the threshold voltage V of depletion type NMOS tube_DQuadratic function, and of the present utility model with impedance regulate the drain terminal electric current I exhausting depletion type NMOS tube in pipe reference circuit_D103It is the threshold voltage V of depletion type NMOS tube_DLinear function (wherein can ignore itemIt is apparent that the drain terminal electric current I exhausting depletion type NMOS tube in pipe reference circuit regulated with impedance of the present utility model_D103Threshold voltage V by depletion type NMOS tube_DImpact less, technique dependency is less, is more suitable for actual production；And from formula (6) as long as it is found that selecting suitable resistance value Z can realize smaller I_D103Thus realizing and the independence of supply voltage VDD better, so there is no need to use tradition to exhaust and enhancement mode reference circuit falls the long pipe of width, reduce depletion type NMOS tube 103 and area that enhancement mode NMOS tube 105 takies, better reduce chip cost, be more suitable for actual production.

Embodiment two

As it is shown on figure 3, the present embodiment provides the another embodiment exhausting pipe reference circuit regulated with impedance of the present utility model, the described pipe reference circuit that exhausts with impedance adjustment at least includes:

Drain terminal connects the depletion type NMOS tube 103 of supply voltage VDD, and the source of described depletion type NMOS tube 103 is connected with the first end of impedance, and the grid end of described depletion type NMOS tube 103 is connected with the second end of described impedance；The enhancement mode NMOS tube 105 of source ground connection, the grid end of described enhancement mode NMOS tube 105 is connected with the second end of described impedance after being connected with the drain terminal of described enhancement mode NMOS tube 105, and the drain terminal of described enhancement mode NMOS tube 105 is outfan, output reference voltage VREF.

It is different in that, realizes resistance value by FUSE (fuse) method trimmed variable.In the present embodiment, described impedance is the resistance that resistance is variable.Specifically, as it is shown on figure 3, described impedance is resistance string, including the first resistance the 106, second resistance 107 and the 3rd resistance 108, the present embodiment is only used as example, and in resistance string, the quantity of resistance can do concrete setting according to actual needs.Each resistance two ends parallel connection fuse, by blowing fuse or not blowing fuse and adjust resistance value.In order to save cost and guarantee there is resistant series all the time between the source and the drain terminal of described enhancement mode NMOS tube 105 of described depletion type NMOS tube 103, in the present embodiment, described 3rd resistance 108 two ends fuse not in parallel, described first resistance 106 two ends the first fuse in parallel, the two ends of described first fuse connect the first burning aluminum pad P1 and the second respectively and burn aluminum pad P2；Described second resistance 107 two ends the second fuse in parallel, the two ends of described second fuse connect the second burning aluminum pad P2 and the three respectively and burn aluminum pad P3.Executing high current burning on aluminum pad, improve temperature by electromigration and can blow fuse, if described first fuse blows, it is the first resistance 106 that described first burning aluminum pad P1 and described second burns impedance between aluminum pad P2；If described first fuse does not blow, it is 0 that described first burning aluminum pad P1 and described second burns impedance between aluminum pad P2.Described equally second burns aluminum pad P2 and the described 3rd impedance burning between aluminum pad P3 can also pass through to blow and do not blow two states to take impedance 107 and 0.Utilizing the FUSE method for repairing and regulating of the program, it is possible to well solve the drift of the reference voltage V REF that process deviation brings, this FUSE trims the quantity that circuit can also burn aluminum pad by increasing FUSE trim and improves the scope and precision that trim simultaneously.

The FUSE of the present embodiment trim circuit and the drain terminal electric current of depletion type NMOS tube in embodiment one, the drain terminal electric current of enhancement mode NMOS tube, reference voltage V REF relational expression identical, the reference voltage unrelated with temperature and supply voltage can be obtained by identical method, not repeat one by one at this.

Exhaust pipe reference circuit as it has been described above, of the present utility model with what impedance regulated, have the advantages that

The reference voltage exhausting the output of pipe reference circuit regulated with impedance of the present utility model is temperature independent, unrelated with supply voltage, takies that chip area is little, technique dependency is little, precision is easy to control simultaneously, is suitable to actual production and use.

In sum, this utility model provides a kind of and exhausts pipe reference circuit with what impedance regulated, at least include: drain terminal connects the depletion type NMOS tube of supply voltage, the source of described depletion type NMOS tube is connected with the first end of impedance, and the grid end of described depletion type NMOS tube is connected with the second end of described impedance；The enhancement mode NMOS tube of source ground connection, the grid end of described enhancement mode NMOS tube is connected with the second end of described impedance after being connected with the drain terminal of described enhancement mode NMOS tube, and the drain terminal of described enhancement mode NMOS tube is outfan.The reference voltage exhausting the output of pipe reference circuit regulated with impedance of the present utility model is temperature independent, unrelated with supply voltage, takies that chip area is little, technique dependency is little, precision is easy to control simultaneously, is suitable to actual production and use.So, this utility model effectively overcomes various shortcoming of the prior art and has high industrial utilization.

Above-described embodiment only illustrative principle of the present utility model and effect thereof, not for restriction this utility model.Above-described embodiment all under spirit of the present utility model and category, can be modified or change by any those skilled in the art.Therefore, art has all equivalence modification or changes that usually intellectual completes under the spirit disclosed without departing from this utility model with technological thought such as, must be contained by claim of the present utility model.

Claims (3)

1. one kind exhausts pipe reference circuit with what impedance regulated, it is characterised in that the described pipe reference circuit that exhausts with impedance adjustment at least includes:

Drain terminal connects the depletion type NMOS tube of supply voltage, and the source of described depletion type NMOS tube is connected with the first end of impedance, and the grid end of described depletion type NMOS tube is connected with the second end of described impedance；The enhancement mode NMOS tube of source ground connection, the grid end of described enhancement mode NMOS tube is connected with the second end of described impedance after being connected with the drain terminal of described enhancement mode NMOS tube, and the drain terminal of described enhancement mode NMOS tube is outfan.

2. according to claim 1 exhaust pipe reference circuit with what impedance regulated, it is characterised in that: described impedance is the resistance that resistance is fixing.

3. according to claim 1 with impedance regulate exhaust pipe reference circuit, it is characterized in that: described impedance includes a resistance string, each resistance two ends parallel connection fuse, each fuse two ends connect pad, control fuse by pad and blow or do not blow and adjust resistance value with this.