CN103955252B - The reference current generating circuit of three-dimensional storage and the method for generation reference current thereof - Google Patents

Abstract

The invention discloses a kind of zero-temperature coefficient reference current generating circuit towards three-dimensional storage, this reference current generating circuit comprises voltage generating module and current generating module, wherein: voltage generating module is used for producing temperature coefficient and all adjustable the second voltage V of magnitude of voltage ₂; Current generating module is used for producing the electric current I of zero-temperature coefficient _ref, wherein, current generating module is formed in parallel by the nmos pass transistor that two are all operated in saturation region, the second voltage V that voltage generating module produces ₂be connected to the grid end of two nmos pass transistors, one of them nmos pass transistor is at the second voltage V simultaneously ₂effect under produce the electric current of positive temperature coefficient (PTC), another nmos pass transistor is at the second voltage V ₂effect under produce the electric current of negative temperature coefficient, by the combination of the electric current of positive temperature coefficient (PTC) and the electric current of negative temperature coefficient, current generating module exports the electric current I of zero-temperature coefficient _ref.The invention also discloses a kind of method of the generation zero-temperature coefficient reference current towards three-dimensional storage.

Description

The reference current generating circuit of three-dimensional storage and the method for generation reference current thereof

Technical field

The invention belongs to technical field of memory, especially three-dimensional storage field, be that a kind of implementation is simple, the zero-temperature coefficient reference current generating circuit towards three-dimensional storage that covers all process corner and the method producing reference current thereof.

Background technology

In memory circuitry application, the generation of reference current has two kinds of modes, and one uses memory device to produce reference current, and the another kind of specialized circuitry that uses produces reference current.For in rear a kind of form, especially in the middle of the application of three-dimensional storage, in order to the consistance of read operation, improve the nargin of read operation, needs temperature influence little, be worth reference current within the specific limits, with its reference current as read operation.

In order to reduce the impact of temperature, prior art provides a kind of not by the stable reference current source of influence of temperature change, as bandgap reference current source (Bandgap Reference Current Source).In simple terms, bandgap reference current source is by positive temperature coefficient (PTC) (Proportional to absolute temperature, electric current (the Complementary to absolute temperature of electric current PTAT) and a negative temperature coefficient, CTAT) superimposed in certain proportion, thus obtain the electric current of a zero-temperature coefficient.

With reference to figure 1, in prior art, bandgap reference current source 10 comprises: start-up circuit 100 and bandgap reference circuit 102.Start-up circuit 100 starts bandgap reference circuit 102 when supply voltage VDD is greater than the source grid voltage difference of P-type crystal pipe 104 and 106 and works.As shown in Figure 1, in bandgap reference circuit 102, the positive-negative input end voltage V of power amplifier 108 _aand V _bequal (V _a=V _b=V _bE1), by transistor Q ₁and Q ₂base emitter voltage difference V _bE1-V _bE2and resistance is the resistance R of R ₁, can generation current I _ptat, as shown in formula (1):

Wherein, transistor Q ₂can be considered K transistor Q ₁be formed in parallel.Due to limit voltage V _tpositive temperature coefficient (PTC), by formula (1), if resistance is zero-temperature coefficient, then known resistance R ₁contained electric current I _ptatit is positive temperature coefficient (PTC) electric current.

On the other hand, by double carrier transistor Q ₁base emitter voltage difference V _eB1and resistance is a resistance R of L*R ₂, can generation current Ictat, shown in (2):

Wherein, due to V _bE1there is negative temperature coefficient, if the temperature coefficient of resistance R2 is zero, so I _ctatit is exactly negative temperature parameter current.

So electric current I _ref, shown in (3):

By to electric current I _refto temperature differentiate, if the temperature coefficient of resistance is zero, can obtain shown in formula (4):

(5)

                                                  

Wherein, base emitter voltage difference V _bE1with critical voltage V _tafter time partial differential, be respectively negative temperature coefficient and positive temperature coefficient (PTC), if use the good resistance type of temperature coefficient in circuit, so can be obtained by formula (5), by the I regulating L to obtain reasonable temperature coefficient _ref.

But the good resistance of temperature coefficient is generally metallic resistance, the area that it takies in three-dimensional storage is larger.

According to the resistance that temperature coefficient is non-vanishing, area will have superiority, the temperature coefficient of its electric current is as shown in formula (6).Its Chinese style (6-1) is the temperature coefficient of resistance is positive situation, and formula (6-2) is the temperature coefficient of resistance is negative situation.

If the temperature coefficient expected, just can only regulating resistance multiple L, two double carrier transistors multiple K, no matter and the temperature coefficient of resistance is just or be negative, only by regulating these two parameters, the temperature coefficient obtained when meeting all process corner is all more difficult.

In sum, there is following problem in existing reference current generating circuit: implementation is complicated, can not meet reference current under all process corner can realize good temperature coefficient.

Summary of the invention

(1) technical matters that will solve

In view of this, fundamental purpose of the present invention be to provide a kind of that can use in three-dimensional storage, implementation simple, under different two process corner, all can meet the zero-temperature coefficient reference current generating circuit towards three-dimensional storage of reference current and produce the method for reference current, with requirement that is high to reference current temperature coefficient precision in meeting requirements on three-dimensional storer, zero-temperature coefficient, reach in large-scale production the object meeting product yield.

(2) technical scheme

For achieving the above object, the invention provides a kind of zero-temperature coefficient reference current generating circuit towards three-dimensional storage, this reference current generating circuit comprises voltage generating module and current generating module, wherein: voltage generating module is used for producing temperature coefficient and all adjustable the second voltage V of magnitude of voltage ₂; Current generating module is used for producing the electric current I of zero-temperature coefficient _ref, wherein, current generating module is formed in parallel by the nmos pass transistor that two are all operated in saturation region, the second voltage V that voltage generating module produces ₂be connected to the grid end of two nmos pass transistors, one of them nmos pass transistor is at the second voltage V simultaneously ₂effect under produce the electric current of positive temperature coefficient (PTC), another nmos pass transistor is at the second voltage V ₂effect under produce the electric current of negative temperature coefficient, by the combination of the electric current of positive temperature coefficient (PTC) and the electric current of negative temperature coefficient, current generating module exports the electric current I of zero-temperature coefficient _ref.

For achieving the above object, present invention also offers a kind of method producing zero-temperature coefficient reference current, the method comprises: voltage generating module produces a temperature coefficient adjustable, the second voltage V that magnitude of voltage is adjustable ₂; Voltage generating module is by this second voltage V ₂to export in current generating module the grid end of two nmos pass transistors in parallel to simultaneously; And a nmos pass transistor in two nmos pass transistors is at the second voltage V ₂effect under produce the electric current of positive temperature coefficient (PTC), another nmos pass transistor is at the second voltage V ₂effect under produce the electric current of negative temperature coefficient, by the combination of the electric current of positive temperature coefficient (PTC) and the electric current of negative temperature coefficient, current generating module exports the electric current I of zero-temperature coefficient _ref.

(3) beneficial effect

As can be seen from technique scheme, the present invention has following beneficial effect:

1, the method of this zero-temperature coefficient reference current generating circuit towards three-dimensional storage provided by the invention and generation reference current thereof, utilize the nmos pass transistor of two produced Positive and Negative Coefficient Temperature in parallel electric currents, and utilize the temperature coefficient of nmos pass transistor and its grid end the relevant feature of alive temperature coefficient, introduce the temperature coefficient of grid voltage and make up the non-vanishing situation of the temperature coefficient of two nmos pass transistors, under each process corner, all can meet the reference current producing zero-temperature coefficient simultaneously, meet in three-dimensional storage high to reference current temperature coefficient precision, the requirement of zero-temperature coefficient, reach in large-scale production the object meeting product yield.

2, the method for this zero-temperature coefficient reference current generating circuit towards three-dimensional storage provided by the invention and generation reference current thereof, implementation is simple, easy, and standard CMOS process can be used to realize;

3, the method for this zero-temperature coefficient reference current generating circuit towards three-dimensional storage provided by the invention and generation reference current thereof, under all process corner, can realize zero-temperature coefficient reference current.Owing to refer to the voltage V of variable temperature coefficient in the present invention ₂act in current generating module, can make up due to zero-temperature coefficient voltage act in current generating module time, current temperature coefficient with process corner change and be deteriorated, cause current temperature coefficient not meet design requirement.

4, this zero-temperature coefficient reference current generating circuit towards three-dimensional storage provided by the invention and produce the method for reference current, can realize under all process corner, reference current all can ensure rated current ± scope of 10% in.Due to the output voltage V of voltage generating module ₂be the adjustable voltage of value, so when it acts on the grid end of two parallel transistors of current generating module, just can pass through regulation voltage V ₂size regulate the size of electric current I ref.

Accompanying drawing explanation

Fig. 1 is the schematic diagram in the bandgap reference current source producing reference current in prior art.

Fig. 2 is the schematic diagram of the zero-temperature coefficient reference current generating circuit towards three-dimensional storage provided by the invention.

Fig. 3 is the schematic diagram of regulation voltage level module in Fig. 2.

Fig. 4 is a kind of implementation of current generating module in Fig. 2.

Fig. 5 (a), Fig. 5 (b) are V ₂temperature coefficient non-vanishing time, the situation that the temperature coefficient that reference current there will be is non-vanishing.

Fig. 5 (c), Fig. 5 (d) are that in reply Fig. 5 (a), Fig. 5 (b), temperature coefficient is not the solution of the situation of 0, by adjustment V ₂temperature coefficient, the temperature coefficient making reference current final is zero.

[Reference numeral]

V ₁~ the first voltage, namely adjusts the output voltage of voltage temperature coefficient module;

V ₂~ the second voltage, the i.e. output voltage of regulation voltage level module;

K ~ the output voltage of regulation voltage level module and the ratio of input voltage;

The output voltage V of net<y> ~ regulation voltage level module ₂access node;

The node of net<x> ~ operational amplifier positive input terminal access, this node is adjustable;

I ₁the drain-source current of ~ MN1 transistor;

I ₂the drain-source current of ~ MN2 transistor;

The reference current that Iref ~ zero-temperature coefficient reference current generating circuit towards three-dimensional storage provided by the invention exports;

_μthe electron mobility of ~ MOS transistor;

C _{ox_n1}the grid oxide layer electric capacity of ~ MN1 transistor;

C _{ox_n2}the grid oxide layer electric capacity of ~ MN2 transistor;

(W/L) _n1the wide long dimension ratio of ~ MN1 transistor;

(W/L) _n2the wide long dimension ratio of ~ MN2 transistor;

V _gsthe gate source voltage of ~ MOS transistor;

V _{gs_n1}the gate source voltage of ~ MN1 transistor;

V _{gs_n2}the gate source voltage of ~ MN2 transistor;

V _{th_n1}the threshold voltage of ~ MN1 transistor;

V _{th_n2}the threshold voltage of ~ MN2 transistor;

the temperature number of voltage is 0;

the temperature coefficient of voltage is not 0

Embodiment

For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.

As shown in Figure 2, Fig. 2 is the structured flowchart of the zero-temperature coefficient reference current generating circuit towards three-dimensional storage provided by the invention, this reference current generating circuit comprises voltage generating module and current generating module, wherein, voltage generating module is used for producing temperature coefficient and all adjustable the second voltage V of magnitude of voltage ₂; Current generating module is used for producing the electric current I of zero-temperature coefficient _ref, current generating module is formed in parallel by the nmos pass transistor that two are all operated in saturation region, the second voltage V that voltage generating module produces ₂be connected to the grid end of two nmos pass transistors, one of them nmos pass transistor is at the second voltage V simultaneously ₂effect under produce the electric current of positive temperature coefficient (PTC), another nmos pass transistor is at the second voltage V ₂effect under produce the electric current of negative temperature coefficient, by the combination of the electric current of positive temperature coefficient (PTC) and the electric current of negative temperature coefficient, current generating module exports the electric current I of zero-temperature coefficient _ref.

In Fig. 2, it is module and regulation voltage level module that voltage generating module comprises regulation voltage temperature, wherein: regulation voltage temperature is module, for the first voltage V that output temperature coefficient is adjustable ₁to regulation voltage level module; The temperature coefficient of the voltage that this module produces has adjustability.In this module, by adjusting means parameter, the voltage of different temperature coefficients can be obtained.Regulation voltage level module, for regulating the first voltage V ₁magnitude of voltage, obtain temperature coefficient and all adjustable the second voltage V of magnitude of voltage ₂, and by the second voltage V ₂export current generating module to.

Regulation voltage level module comprises an operational amplifier and a resistance string, and as shown in Figure 3, this operational amplifier output terminal is connected to one end of this resistance string, and the other end ground connection of this resistance string forms node between each resistance in this resistance string.In this resistance string, the resistance homogeneous phase of each resistance is all r, by the node called after net<i> formed between each resistance in this resistance string, i ∈ (1, n), from node net<i> to the resistance on ground be r × i.

It is the first voltage V that module exports that the negative input end of this operational amplifier is connected to this regulation voltage temperature ₁positive input terminal is connected to the some node net<x> in this resistance string, and this node variable (in net<x>, x is adjustable in scope of design), and this node is according to the first voltage V ₁value and the second voltage V ₂the relation of both values decide, be namely according to the first voltage V ₁value and the second voltage V ₂the relation of both values positive input terminal that decides this operational amplifier be specifically connected on which node in this resistance string.

The output terminal of this regulation voltage level module is some selected, stationary nodes net<y> extractions from this resistance string, y ∈ (1, n), this stationary nodes net<y> is determined by the adjustment multiple K of this regulation voltage level module, fixing, adjustment multiple K is the ratio of this regulation voltage level module output voltage and input voltage, regulates this adjustment multiple K by the position regulating this operational amplifier positive input terminal to access this resistance string interior joint.The output voltage of regulation voltage level module is identical with the temperature coefficient of input voltage.Shown in above setting and Fig. 3, the magnitude of voltage adjustment multiple K of this regulation voltage level module is:

In Fig. 2, form two nmos pass transistors of current generating module, i.e. the first nmos pass transistor MN1 and the second nmos pass transistor MN2, the equal ground connection of its source, drain terminal is all connected to outside electric current changing voltage module, and this electric current changing voltage module is all operated in saturation region in order to make two nmos pass transistors.By the currents combination of the different temperature coefficients of two nmos pass transistors, current generating module exports the electric current I of zero-temperature coefficient _ref.

In the design of the reference current of memory circuitry, two indices to be ensured: one is that the temperature coefficient of reference current is relatively good simultaneously; Two are, the value of reference current in the scope of a regulation (such as, the design load ± 1u of circuit design reference current, this design load is determined by information such as techniques).For second index, be by changing the second voltage V in the present invention ₂value, change the size of electric current.And in process for first index, the present invention effectively can cover all process corner, realizes the reference current close to zero-temperature coefficient.

Based on the zero-temperature coefficient reference current generating circuit towards three-dimensional storage shown in Fig. 1 to Fig. 3, present invention also offers a kind of method producing zero-temperature coefficient reference current, the method comprises:

Step 1: voltage generating module produces a temperature coefficient adjustable, the second voltage V that magnitude of voltage is adjustable ₂;

Step 2: voltage generating module is by this second voltage V ₂to export in current generating module the grid end of two nmos pass transistors in parallel to simultaneously;

Step 3 a: nmos pass transistor in two nmos pass transistors is at the second voltage V ₂effect under produce the electric current of positive temperature coefficient (PTC), another nmos pass transistor is at the second voltage V ₂effect under produce the electric current of negative temperature coefficient, by the combination of the electric current of positive temperature coefficient (PTC) and the electric current of negative temperature coefficient, current generating module exports the electric current I of zero-temperature coefficient _ref.

In step 3, by regulating the second voltage V ₂temperature coefficient make two in parallel nmos pass transistors obtain the electric current I of zero-temperature coefficients _ref, by regulating the second voltage V ₂numerical value regulate electric current I _refthe size of value is to satisfy the demand.

Below in conjunction with specific embodiment, specific implementation of the present invention is described.

As shown in Figure 2, present invention utilizes following 2 electric currents producing zero-temperature coefficient: the first, be used in grid terminal voltage (V ₂) temperature coefficient is when being zero, the pipe producing Positive and Negative Coefficient Temperature is in parallel, offsets portion temperature coefficient; The second, if do not have the electric current that can obtain zero-temperature coefficient, the temperature coefficient of reference current can also be regulated by the temperature coefficient changing grid terminal voltage at first.The method of the derivation of equation is used to verify realizability of the present invention below in conjunction with these 2.Illustrate for electric current producing method 4 (a).

First suppose at the second voltage V ₂not variation with temperature and changing, as shown in Fig. 4 (a), current generating module is made up of MN1 and MN2, and wherein MN1 produces the electric current I of negative temperature coefficient ₁, MN2 produces the electric current I of positive temperature coefficient (PTC) ₂, reference current I _reffor electric current I ₁with electric current I ₂sum.

In the present embodiment, this transistor MN1 and MN2 is operated in saturation region, ignores the channel modulation effect of MN1 and MN2, and by shown in Fig. 4 (a), the grid terminal voltage of transistor MN1 with MN2 is identical, all equals the second voltage V ₂, that is V _{gs_n1}=V _{gs_n1}=V ₂-V _sS=V ₂-0=V ₂, the electric current that can obtain transistor MN1 and MN2 is respectively:

Reference current I _reffor:

$I_{\mathrm{ref}}=I_1+I_2=\frac{1}{2}{\mathrm{\&mu;C}}_{\mathrm{ox}\_n1}{\left(\frac{W}{L}\right)}_{n1}{(V_2-V_{\mathrm{th}\_n1})}^2+\frac{1}{2}{\mathrm{\&mu;C}}_{\mathrm{ox}\_n2}{\left(\frac{W}{L}\right)}_{n2}{(V_2-V_{\mathrm{th}\_n2})}^2---\left(9\right)$

If the grid terminal voltage V of transistor MN1 and MN2 ₂do not vary with temperature, to the current vs. temperature differentiate respectively of transistor MN1 and MN2, suppose, then the current temperature coefficient of transistor MN1 and MN2 is:

$\left\{\begin{array}{c}{\left(\frac{{\&PartialD;I}_1}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}=0}\&ap;\frac{1}{2}{C}_{\mathrm{ox}\_n1}{\left(\frac{W}{L}\right)}_{n1}{(V_2-V_{\mathrm{th}\_n1})}^2\&CenterDot;\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}-{\mathrm{\&mu;C}}_{\mathrm{ox}\_n1}{\left(\frac{W}{L}\right)}_{n1}\&CenterDot;V_{\mathrm{th}\_n1}\&CenterDot;\frac{\&PartialD;V_{\mathrm{th}\_n1}}{\&PartialD;T}\\ {\left(\frac{{\&PartialD;I}_2}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}=0}\&ap;\frac{1}{2}{C}_{\mathrm{ox}\_n2}{\left(\frac{W}{L}\right)}_{n2}{(V_2-V_{\mathrm{th}\_n2})}^2\&CenterDot;\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}-{\mathrm{\&mu;C}}_{\mathrm{ox}\_n2}{\left(\frac{W}{L}\right)}_{n2}\&CenterDot;V_{\mathrm{th}\_n2}\&CenterDot;\frac{\&PartialD;V_{\mathrm{th}\_n2}}{\&PartialD;T}\end{array}\right.$

$\&DoubleRightArrow;\left\{\begin{array}{c}{\left(\frac{{\&PartialD;I}_1}{\&PartialD;T}\right)}_{\frac{\&PartialD;V_2}{\&PartialD;T}=0}\&ap;A_1\&CenterDot;\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}-B_1\&CenterDot;\frac{{\&PartialD;V}_{\mathrm{th}\_n1}}{\&PartialD;T}\\ {\left(\frac{{\&PartialD;I}_2}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}=0}\&ap;A_2\&CenterDot;\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}-B_2\&CenterDot;\frac{{\&PartialD;V}_{\mathrm{th}\_n2}}{\&PartialD;T}\end{array}\right.---\left(10\right)$

Wherein $\left\{\begin{array}{c}{A}_1=\frac{1}{2}{C}_{\mathrm{ox}\_n1}{\left(\frac{W}{L}\right)}_{n1}{(V_2-V_{\mathrm{th}\_n1})}^2,B_1={\mathrm{\&mu;C}}_{\mathrm{ox}\_n1}{\left(\frac{W}{L}\right)}_{n1}\&CenterDot;V_{\mathrm{th}\_n1}\\ A_2=\frac{1}{2}{C}_{\mathrm{ox}\_n2}{\left(\frac{W}{L}\right)}_{n2}{(V_2-V_{\mathrm{th}\_n2})}^2,B_2={\mathrm{\&mu;C}}_{\mathrm{ox}\_n2}{\left(\frac{W}{L}\right)}_{n2}\&CenterDot;V_{\mathrm{th}\_n2}\end{array}\right.$

A in formula (4) ₁, A ₂, B ₁, B ₂it is all non-negative.The temperature coefficient of technological parameter mobility [mu] is threshold V that is negative, pipe _thtemperature coefficient be negative, that is with temperature raise, V _thvalue diminish.To μ, V _thtemperature coefficient take absolute value and can obtain, I ₁and I ₂the temperature coefficient of electric current is:

∴ $\left\{\begin{array}{c}\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}<0\&DoubleRightArrow;\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}=-\left|\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}\right|\\ \frac{{\&PartialD;V}_{\mathrm{th}\_\mathrm{ni}}}{\&PartialD;T}<0\&DoubleRightArrow;\frac{{\&PartialD;V}_{\mathrm{th}}}{\&PartialD;T}=-\left|\frac{{\&PartialD;V}_{\mathrm{th}}}{\&PartialD;T}\right|\end{array}\right.(i=\mathrm{1,2})$

(11)

∵ $\left\{\begin{array}{c}{\left(\frac{{\&PartialD;I}_1}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}=0}\&ap;-A_1\&CenterDot;\left|\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}\right|+B_1\&CenterDot;\left|\frac{{\&PartialD;V}_{\mathrm{th}\_n1}}{\&PartialD;T}\right|\\ {\left(\frac{{\&PartialD;I}_2}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}=0}\&ap;-A_2\&CenterDot;\left|\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}\right|+B_2\&CenterDot;\left|\frac{\&PartialD;V_{\mathrm{th}\_n2}}{\&PartialD;T}\right|\end{array}\right.$

The temperature coefficient of reference current is:

${\left(\frac{{\&PartialD;I}_{\mathrm{ref}}}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}=0}\&ap;-A_1\&CenterDot;\left|\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}\right|+B_1\&CenterDot;\left|\frac{{\&PartialD;V}_{\mathrm{th}\_n1}}{\&PartialD;T}\right|-A_2\&CenterDot;\left|\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}\right|+B_2\&CenterDot;\left|\frac{{\&PartialD;V}_{\mathrm{th}\_n2}}{\&PartialD;T}\right|---\left(12\right)$

As formula (12), even if selected positive and negative two the different pipes of temperature coefficient, under all process corner, making the temperature coefficient of reference current close to zero, has also been impossible.So the temperature coefficient of output current just has three possible situations, for just, zero, negative.Second voltage V ₂temperature coefficient constant time, the non-vanishing situation of the temperature likely occurred is as shown in Fig. 5 (a), Fig. 5 (b).

If change the second voltage V ₂temperature coefficient, as Fig. 5 (c), Fig. 5 (d) just solve the second voltage V respectively ₂temperature coefficient constant time, the problem (as Fig. 5 (a), Fig. 5 (b)) that reference current is non-vanishing.Can obtain temperature differentiate the reference current of formula (9):

$\begin{array}{c}{\left(\frac{{\&PartialD;I}_{\mathrm{ref}}}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}\&NotEqual;0}\&ap;-A_1\&CenterDot;\left|\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}\right|+B_1\&CenterDot;\left|\frac{{\&PartialD;V}_{\mathrm{th}\_n1}}{\&PartialD;T}\right|-A_2\&CenterDot;\left|\frac{\&PartialD;\mathrm{\&mu;}}{\&PartialD;T}\right|+B_2\&CenterDot;\left|\frac{{\&PartialD;V}_{\mathrm{th}\_n2}}{\&PartialD;T}\right|+B_1\&CenterDot;\frac{{\&PartialD;V}_2}{\&PartialD;T}+B_2\&CenterDot;\frac{{\&PartialD;V}_2}{\&PartialD;T}\\ {\left(\frac{{\&PartialD;I}_{\mathrm{ref}}}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}\&NotEqual;0}\&ap;{\left(\frac{{\&PartialD;I}_{\mathrm{ref}}}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}=0}+(B_1+B_2)\&CenterDot;\frac{{\&PartialD;V}_2}{\&PartialD;T}\end{array}---\left(13\right)$

From formula (13), the temperature coefficient of reference current of the present invention can be divided into current generating module certainly in the second voltage V ₂the temperature coefficient introduced in the constant situation of grid terminal voltage and the second voltage V ₂temperature coefficient item introduce temperature coefficient.Known by formula (13), by size, the suitable adjustment second voltage V of transistor MN1 and MN2 in adjustment current generating module ₂temperature coefficient, the temperature coefficient of reference current can be made to level off to 0.Further, by adjusting the second voltage V ₂temperature coefficient, the temperature coefficient that all can obtain under each process corner.

When $\frac{{\&PartialD;V}_2}{\&PartialD;T}=-\frac{{\left(\frac{{\&PartialD;I}_{\mathrm{ref}}}{\&PartialD;T}\right)}_{\frac{\&PartialD;V_2}{\&PartialD;T}=0}}{B_1+B_2}$ Time, ${\left(\frac{{\&PartialD;I}_{\mathrm{ref}}}{\&PartialD;T}\right)}_{\frac{{\&PartialD;V}_2}{\&PartialD;T}\&NotEqual;0}\&ap;0---\left(14\right)$

In sum, by the analysis of the temperature coefficient to reference current, we can draw, by the design suitable to current generating module, and by regulating its second voltage V ₂temperature coefficient, under all process corner, all can realize varying with temperature of output current little, and ensure that current value is in corresponding scope.

In addition, provided by the invention towards in the zero-temperature coefficient reference current generating circuit of three-dimensional storage, the realization of current generating module can have various ways, as Fig. 4 (a), Fig. 4 (b), Fig. 4 (c) etc., thinking is used in multiple branch roads that temperature coefficient under permanent grid voltage can cancel out each other to produce reference current, the present invention is for Fig. 4 (a) introduction, wherein current generating module comprises the pipe of generation positive temperature coefficient (PTC) electric current and each parallel connection (the grid end of pipe of negative temperature parameter current when being operated in saturation region, source, drain terminal, substrate is all connected), grid end is connected to the output voltage V of voltage generating module ₂.Combined by temperature coefficient two factors of the temperature coefficient variable effect pipe generation current of the transistor generation electric current of different temperature coefficients, the grid terminal voltage of pipe, produce the electric current I of zero-temperature coefficient _ref.

Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (14)

1. towards a zero-temperature coefficient reference current generating circuit for three-dimensional storage, it is characterized in that, this reference current generating circuit comprises voltage generating module and current generating module, wherein:

Voltage generating module is used for producing temperature coefficient and all adjustable the second voltage V of magnitude of voltage ₂;

Current generating module is used for producing the electric current I of zero-temperature coefficient _ref, wherein, current generating module is formed in parallel by the nmos pass transistor that two are all operated in saturation region, the second voltage V that voltage generating module produces ₂be connected to the grid end of two nmos pass transistors, one of them nmos pass transistor is at the second voltage V simultaneously ₂effect under produce the electric current of positive temperature coefficient (PTC), another nmos pass transistor is at the second voltage V ₂effect under produce the electric current of negative temperature coefficient, by the combination of the electric current of positive temperature coefficient (PTC) and the electric current of negative temperature coefficient, current generating module exports the electric current I of zero-temperature coefficient _ref.

2. the zero-temperature coefficient reference current generating circuit towards three-dimensional storage according to claim 1, is characterized in that, it is module and regulation voltage level module that described voltage generating module comprises regulation voltage temperature, wherein:

Regulation voltage temperature is module, for the first voltage V that output temperature coefficient is adjustable ₁to regulation voltage level module;

Regulation voltage level module, for regulating the first voltage V ₁magnitude of voltage, obtain temperature coefficient and all adjustable the second voltage V of magnitude of voltage ₂, and by the second voltage V ₂export current generating module to.

3. the zero-temperature coefficient reference current generating circuit towards three-dimensional storage according to claim 2, it is characterized in that, described regulation voltage level module comprises an operational amplifier and a resistance string, and it is the first voltage V that module exports that the negative input end of this operational amplifier is connected to this regulation voltage temperature ₁, positive input terminal is connected to the some nodes in this resistance string, and this node is variable; This operational amplifier output terminal is connected to one end of this resistance string, the other end ground connection of this resistance string, forms node in this resistance string between each resistance.

4. the zero-temperature coefficient reference current generating circuit towards three-dimensional storage according to claim 3, is characterized in that, the positive input terminal of described operational amplifier is connected to the some nodes in this resistance string, and this node is according to the first voltage V ₁value and the second voltage V ₂the relation of both values decide, be namely according to the first voltage V ₁value and the second voltage V ₂the relation of both values positive input terminal that decides this operational amplifier be specifically connected on which node in this resistance string.

5. the zero-temperature coefficient reference current generating circuit towards three-dimensional storage according to claim 3, it is characterized in that, the output terminal of described regulation voltage level module is that some stationary nodes are drawn from this resistance string, this stationary nodes is determined by the adjustment multiple K of this regulation voltage level module, adjustment multiple K is the ratio of this regulation voltage level module output voltage and input voltage, regulates this adjustment multiple K by the position regulating this operational amplifier positive input terminal to access this resistance string interior joint.

6. the zero-temperature coefficient reference current generating circuit towards three-dimensional storage according to claim 3, is characterized in that, the output voltage of described regulation voltage level module is identical with the temperature coefficient of input voltage.

7. the zero-temperature coefficient reference current generating circuit towards three-dimensional storage according to claim 1, it is characterized in that, two nmos pass transistors of described formation current generating module, the equal ground connection of its source, drain terminal is all connected to outside electric current changing voltage module, and this electric current changing voltage module is all operated in saturation region in order to make two nmos pass transistors.

8. produce a method for zero-temperature coefficient reference current, be applied to the reference current generating circuit according to any one of claim 1 to 7, it is characterized in that, the method comprises:

Voltage generating module produces a temperature coefficient adjustable, the second voltage V that magnitude of voltage is adjustable ₂;

Voltage generating module is by this second voltage V ₂to export in current generating module the grid end of two nmos pass transistors in parallel to simultaneously; And

A nmos pass transistor in two nmos pass transistors is at the second voltage V ₂effect under produce the electric current of positive temperature coefficient (PTC), another nmos pass transistor is at the second voltage V ₂effect under produce the electric current of negative temperature coefficient, by the combination of the electric current of positive temperature coefficient (PTC) and the electric current of negative temperature coefficient, current generating module exports the electric current I of zero-temperature coefficient _ref.

9. the method for generation zero-temperature coefficient reference current according to claim 8, it is characterized in that, it is module and regulation voltage level module that described voltage generating module comprises regulation voltage temperature, and wherein, regulation voltage temperature is adjustable the first voltage V of module output temperature coefficient ₁to regulation voltage level module; Regulation voltage level module regulates the first voltage V ₁magnitude of voltage, obtain temperature coefficient and all adjustable the second voltage V of magnitude of voltage ₂, and by the second voltage V ₂export current generating module to.

10. the method for generation zero-temperature coefficient reference current according to claim 9, it is characterized in that, described regulation voltage level module comprises an operational amplifier and a resistance string, and it is the first voltage V that module exports that the negative input end of this operational amplifier is connected to this regulation voltage temperature ₁, positive input terminal is connected to the some nodes in this resistance string, and this node is variable; This operational amplifier output terminal is connected to one end of this resistance string, the other end ground connection of this resistance string, forms node in this resistance string between each resistance.

The method of 11. generation zero-temperature coefficient reference currents according to claim 10, it is characterized in that, the positive input terminal of described operational amplifier is connected to the some nodes in this resistance string, this node is according to the first voltage V ₁value and the second voltage V ₂the relation of both values decide, be namely according to the first voltage V ₁value and the second voltage V ₂the relation of both values positive input terminal that decides this operational amplifier be specifically connected on which node in this resistance string.

The method of 12. generation zero-temperature coefficient reference currents according to claim 10, it is characterized in that, the output terminal of described regulation voltage level module is that some stationary nodes are drawn from this resistance string, this stationary nodes is determined by the adjustment multiple K of this regulation voltage level module, adjustment multiple K is the ratio of this regulation voltage level module output voltage and input voltage, regulates this adjustment multiple K by the position regulating this operational amplifier positive input terminal to access this resistance string interior joint.

The method of 13. generation zero-temperature coefficient reference currents according to claim 10, it is characterized in that, the output voltage of described regulation voltage level module is identical with the temperature coefficient of input voltage.

The method of 14. generation zero-temperature coefficient reference currents according to claim 8, it is characterized in that, two nmos pass transistors of described formation current generating module, the equal ground connection of its source, drain terminal is all connected to outside electric current changing voltage module, and this electric current changing voltage module is all operated in saturation region in order to make two nmos pass transistors.