CN101178610A - Circuit outputting adjustable positive and negative or zero-temperature coefficient electrical current and voltage reference - Google Patents

Abstract

The invention provides a circuit for outputting current and voltage references with adjustable positive, negative or zero temperature coefficients, and comprises: a start circuit, a current generation circuit with positive and negative temperature coefficients, a feedback stabilized deduced circuit and a current deduced circuit with negative temperature coefficient, a composite circuit of current and voltage references with adjustable temperature coefficients. The invention is realized based on the standard CMOS technique with simple structure and lower input voltage, and the produced temperature coefficients are adjustable, namely, the temperature coefficients can be the current and voltage references with adjustable positive, negative or zero temperature coefficients.

Description

A kind of circuit of exporting adjustable positive and negative or zero-temperature coefficient electrical current, voltage reference

Technical field

The invention belongs to the circuit engineering field, particularly a kind ofly export adjustable positive and negative or zero-temperature coefficient electrical current, voltage reference circuit.

Background technology

The function of current reference and voltage reference respectively in circuit other functional modules reference current and reference voltage are provided, all be very important for oscillator, wave filter, digital-to-analog conversion and precise time time delay module.May need the curtage of different temperature coefficients for the circuit of difference in functionality, in the breadboardin debug process, need temperature coefficient is regulated.And some circuit working can reduce power consumption like this under lower supply voltage.In addition, also need to save chip area in the integrated circuit (IC) products of some specific uses, save the space or reduce cost, this just needs the circuit structure cannot be complicated, realizes same current reference or voltage reference function with very simple structure.

Common current reference adopts classical auto bias circuit, can only produce the PTAT electric current, also will just can produce zero-temperature coefficient electrical current through the processing of follow-up other circuit; And voltage reference output voltage values relatively more commonly used at present is substantially constant at about 1.25V, and there is operational amplifier to guarantee that two output end voltages of band-gap circuit equate in the circuit, also just require operational amplifier to have high-gain, low imbalance characteristic, the operational amplifier design difficulty is strengthened, therefore, just require circuit structure is improved.

Summary of the invention

Technical matters to be solved by this invention is at deficiency of the prior art, and a kind of circuit that produces adjustable positive and negative or zero-temperature coefficient electrical current, voltage reference is provided.This circuit can be operated under the supply voltage lower about 1.5V, can regulate the electric current that produces various positive and negative or zero-temperature coefficients, obtains required reference voltage value.In addition, circuit structure is very simple, has improved general auto bias circuit, and entire circuit has only 11 MOS transistor, two diodes and four resistance.

The present invention adopts following technical scheme:

A kind of circuit of exporting adjustable positive and negative or zero-temperature coefficient electrical current, voltage reference, comprise: start-up circuit, positive and negative temperature coefficient current generating circuit, feedback stability and negative temperature parameter current derived circuit, the current reference that temperature coefficient is adjustable, voltage reference combiner circuit; Described start-up circuit is positive and negative temperature coefficient current generating circuit, and the positive temperature coefficient (PTC) electric current output in the current reference that temperature coefficient is adjustable, the voltage reference combiner circuit provides the startup bias voltage; Described positive and negative temperature coefficient current generating circuit produces the electric current with positive and negative temperature coefficient; Described feedback stability and negative temperature parameter current derived circuit are stablized current mirror and the heavy gate bias voltage of electric current in the positive and negative temperature coefficient current generating circuit, participate in the electric current of synthetic negative temperature coefficient; The current reference that described temperature coefficient is adjustable, voltage reference combiner circuit output two-way electric current, one the tunnel is the positive temperature coefficient (PTC) electric current, another road is a negative temperature parameter current, positive and negative temperature coefficient electric current is superposeed by resistance, produce the current reference or the voltage reference of zero-temperature coefficient or different temperature coefficients; The input end of the positive and negative temperature coefficient current generating circuit of output termination of start-up circuit; First end output of positive and negative temperature coefficient current generating circuit connects the input of feedback circuit, adjustable current reference, the voltage reference combiner circuit of second and third end output jointing temp coefficient; The output of feedback stability and negative temperature parameter current derived circuit feeds back to positive and negative temperature coefficient current generating circuit again; Positive and negative or the zero-temperature coefficient electrical current benchmark of the current reference that temperature coefficient is adjustable, voltage reference combiner circuit output, voltage reference.

Start-up circuit of the present invention is: two PMOS transistor M1 and M2 constitute current mirror, its source electrode is connected with power supply, its grid links to each other with the drain electrode of a PMOS transistor M3, also link to each other with resistance R 1 one ends and M1 drain electrode, resistance R 1 other end ground connection VSS, transistor M2 drain electrode connects just described, negative temperature parameter current produces nmos pass transistor M7 in the circuit, the grid of M8 and M9, transistor M3 source electrode connects power supply, and its grid connects just described, negative temperature parameter current produces circuit PMOS transistor M4, M5, the grid of M6 and described electric current, the grid of PMOS transistor M12 in the voltage reference combiner circuit.

Described positive and negative temperature coefficient current generating circuit is: the current mirror that PMOS transistor M4, M5 and M6 common gate constitute, the electric current that nmos pass transistor M7, M8 and M9 common gate constitute sinks and PMOS transistor M10 forms improved automatic biasing structure, be divided into three the tunnel, the first via is made of transistor M4, M7 and diode D1, transistor M4 source electrode connects power supply, transistor M4 grid, leakage are connected to the drain electrode of transistor M7, and transistor M7 source electrode connects the D1 anode, D1 plus earth VSS; The second road M5, M8, resistance R 2 and diode D2 constitute, the M5 source electrode connects power supply, drain electrode connects the grid that M10, M11 in feedback and the output circuit are also received in the M8 drain electrode, M8 source electrode connecting resistance R2 one end, resistance R 2 another terminating diode D2 anodes, diode D2 plus earth VSS, the electric current of generation positive temperature coefficient (PTC) on resistance R 2; Third Road is made of M6, M9 and resistance R 3, and the M6 source electrode connects power supply, and drain electrode connects M9 grid and drain electrode, M9 source electrode connecting resistance R3 one end, and the drain electrode of also receiving M10, resistance R 3 other ends are linked ground, produce negative temperature parameter current on the resistance R 3.

Feedback stability of the present invention and negative temperature parameter current derived circuit are: be made of a PMOS pipe M10, PMOS pipe M10 source electrode connects power supply, and its grid connects M5 and M8 drain electrode, the source electrode of PMOS pipe M10 drain electrode connecting resistance R3 one end and M9

The current reference that temperature coefficient of the present invention is adjustable, voltage reference combiner circuit are: two PMOS manage M11 and M12, and the source electrode of PMOS pipe M11 and M12 connects power supply; The M11 grid connects the M10 grid, PMOS pipe M11 mirror image PMOS pipe M10 synthesizes negative temperature parameter current and manages M11 drain electrode output negative temperature parameter current from PMOS, the M12 grid connects the positive temperature coefficient (PTC) electric current that produces on the grid mirror image resistance R 2 of M5, resistance R 4 one ends connect the drain electrode of M11 and M12, resistance R 4 its other end ground connection VSS.

The present invention has tangible advantage, and is better than reference current, voltage source commonly used at present aspect a lot:

(1) circuit structure is very simple, comprises start-up circuit, positive and negative temperature coefficient current generating circuit, feedback stability and negative temperature parameter current derived circuit, the current reference that temperature coefficient is adjustable, voltage reference combiner circuit.Entire circuit is only by 11 MOS transistor, and two diodes and four resistance constitute, and have reduced chip area greatly.

(2) improved the auto bias circuit of generation commonly used and the reference current of independent of power voltage, improvements be its feedback, only utilize a PMOS pipe to realize two functions dexterously: feedback stability bias voltage and synthesize the derivation negative temperature parameter current.

(4) adjustable current reference, the voltage reference combiner circuit of temperature coefficient can make the reference current that is produced, the temperature coefficient adjustable size of voltage among the present invention, any positive and negative or null value of furnishing, and realize that circuit structure is simple.

(5) circuit can be operated under the low voltage, is about 1.5V.Because the backfeed loop in the circuit does not adopt high performance operational amplifier, but adopt as described in (1) only a PMOS transistor stablize bias voltage.

Describe concrete enforcement of the present invention in detail below in conjunction with accompanying drawing, technical solution of the present invention is further described.

Description of drawings

Fig. 1 is a structured flowchart of the present invention.

Fig. 2 is circuit theory diagrams of the present invention.

Description of reference numerals:

1-start-up circuit; 2-positive and negative temperature coefficient electric current 3-feedback stability circuit and subzero temperature

Produce circuit; Degree coefficient current derived circuit;

What 4-temperature coefficient was adjustable

Stream, voltage reference combiner circuit.

Embodiment

Export the circuit of adjustable positive and negative or zero-temperature coefficient electrical current, voltage reference, shown in Fig. 1 circuit structure diagram, be divided into start-up circuit 1, positive and negative temperature coefficient current generating circuit 2, feedback stability and negative temperature parameter current derived circuit 3, the current reference that temperature coefficient is adjustable, voltage reference combiner circuit 4 be totally 4 parts.The direct current input end of 4 partial circuits connects direct supply VCC respectively.The input end of the positive and negative temperature coefficient current generating circuit of output termination of start-up circuit; First end output of positive and negative temperature coefficient current generating circuit connects the input of feedback circuit, adjustable current reference, the voltage reference combiner circuit of second and third end output jointing temp coefficient; The output of feedback circuit feeds back to positive and negative temperature coefficient current generating circuit again; The current reference that temperature coefficient is adjustable, the positive and negative or zero-temperature coefficient (PTAT of voltage reference combiner circuit output, Proportional to Absolute Temperature, CTAT, Complementary to Absolute Temperature, ZTC, Zero-Temperature-Coefficient) current reference, voltage reference (VREF).

Wherein, as shown in Figure 2, the structure of described start-up circuit 1 is: two PMOS transistor M1 and M2 constitute current mirror, its source electrode is connected with power supply, its grid links to each other with the drain electrode of a PMOS transistor M3, also links to each other R1 other end ground connection VSS with resistance R 1 one ends and M1 drain electrode.The M2 drain electrode connects the grid of M7, M8, M9 in the described positive and negative temperature coefficient current generating circuit of claim 1.The M3 source electrode connects power supply, and the grid that grid connects current mirror in positive and negative temperature coefficient current generating circuit, the voltage reference combiner circuit is the grid of M4, M5, M6, M12.

Described positive and negative temperature coefficient current generating circuit 2 structures are: the current mirror that PMOS transistor M4, M5, M6 common gate constitute, the electric current that nmos pass transistor M7, M8, M9 common gate constitute sinks and PMOS transistor M10 forms improved automatic biasing structure, be divided into three the tunnel, the first via is made of M4, M7, diode D1, the M4 source electrode connects power supply, grid, leakage are connected to the drain electrode of M7, and the M7 source electrode connects the D1 anode, D1 plus earth VSS; The second road M5, M8, resistance R 2, diode D2 constitute, and the M5 source electrode connects power supply, and drain electrode connects the grid that M10, M11 in feedback and the output circuit are also received in the M8 drain electrode, the M8 source electrode connects R2 one end, another termination of R2 D2 anode, D2 plus earth VSS, the electric current of generation positive temperature coefficient (PTC) on R2; Third Road is made of M6, M9, resistance R 3, and the M6 source electrode connects power supply, and drain electrode connects M9 grid and drain electrode, and the M9 source electrode connects R3 one end, the drain electrode of also receiving M10, and the R3 other end is linked ground, the last generation of R3 negative temperature parameter current.

The structure of described feedback stability and negative temperature parameter current derived circuit 3 is: be made of a PMOS pipe M10, the M10 source electrode connects power supply, and grid connects M5 and M8 drain electrode, and drain electrode connects the source electrode of R3 one end and M9.

The structure of the current reference that described temperature coefficient is adjustable, voltage reference combiner circuit 4 is: two PMOS manage M11 and M12, its source electrode connects power supply, the M11 grid connects the M10 grid, the negative temperature parameter current that mirror image M10 is synthetic and from M11 drain electrode output negative temperature parameter current, the grid mirror image R2 that the M12 grid meets M5 goes up the positive temperature coefficient (PTC) electric current that produces.Resistance R 4 one ends connect the drain terminal of M11 and M12, an end ground connection VSS.

The principle of work of this circuit: behind the energized voltage VCC, end when M3 begins in the start-up circuit, the M1 conducting of diode connection, produce one road electric current and flow through M1 and R1, M1 arrives M2 with current mirror, makes M2 that drain electrode produces voltage, the gate input that connection M7, M8, M9 electric current sink because M2 drains, can can make improved auto bias circuit break away from " degeneracy " bias point for it provides bias voltage.After subsequent conditioning circuit was started working, the M3 conducting was raised the M1 grid potential, and M1 ends, and start-up circuit turn-offs, and subsequent conditioning circuit is not exerted an influence.In the improved auto bias circuit, the breadth length ratio of M4, M5, M6 is identical, the breadth length ratio of M7, M8, M9 is identical, so M7, M8 source potential are identical, therefore the voltage that can obtain on the R2 is the poor of diode D1 and D2 forward voltage, this voltage difference is a positive temperature coefficient (PTC), so R2 goes up generation positive temperature coefficient (PTC) electric current.The last voltage of R3 is the forward voltage of D1, and this voltage is negative temperature coefficient, produces negative temperature parameter current so R3 goes up.In order to stablize M7, M8, the equal M10 of introducing of M9 drain voltage, stabilization process: when the M8 drain voltage rises, then the M10 grid potential raises, the electric current that flows through M10 reduces, the M9 source voltage terminal descends, and M9 is the diode connection, so its grid potential also descends, thereby the M5 drain potential descends, and plays stabilization.Simultaneously M10 also has the effect of synthetic negative temperature parameter current because the electric current that flows through R3 is for flowing through M10, M6 electric current sum, and R3 to go up electric current be negative temperature coefficient, M6 is last to be positive temperature coefficient (PTC), so M10 upward is a negative temperature coefficient.M11 and M10 common gate, mirror image the electric current of M1, thereby output negative temperature coefficient electric current; M12 and M5 common gate, thus mirror image the electric current of electric current output positive temperature coefficient (PTC) of M5.Regulate the breadth length ratio of M12 and M11, just can obtain the reference current of different temperature coefficients, this reference current flows through the reference voltage that R4 just can obtain different temperature coefficients, comprise the zero-temperature coefficient reference voltage, certainly R4 also can the resistance in series potential-divider network so that obtain different reference voltage values simultaneously.

Fig. 1 has provided structured flowchart.Narrate the principle of work of this circuit below.

Generally, the DC characteristic of diode is provided by following formula:

$I_D=I_S{e}^{V_d/V_T}---\left(1\right)$

I _DIt is diode current; I _SBe anti-phase saturation current, relevant with the area of diode; V _dBe the voltage on the diode; V _TBe thermal voltage, have positive temperature coefficient (PTC).If the electric current I of known diode _D, then can derive the voltage V at diode two ends _d:

$V_d=V_T\ln \frac{I_D}{I_S}---\left(2\right)$

The automatic biasing current generating circuit of the improved and independent of power voltage of structure shown in Figure 2.The breadth length ratio of M7, M8, M9 is identical, so M7, M8 source potential are identical, so the voltage at D1 two ends must equal the voltage sum at D2 and resistance R 2 two ends, therefore:

V _D1＝I _D2R+V _D2 (3)

Electric current on the R2 is:

$I_{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}2}=\frac{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="V\; D"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">V</figure-callout>}}_D}{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}=V_T\ln \left(\frac{{\mathrm{<figure-callout\; id="1"\; label="I\; D"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">I</figure-callout>}}_D/I_{S1}}{I_{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">D</figure-callout>}2}/I_{S2}}\right)---\left(4\right)$

Wherein, the electric current that flows through D1 and D2 is equal, i.e. I _D1=I _D2, the emitter area of establishing D2 is K a times of D1, K is greater than 1.(4) abbreviation is:

$I_{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}2}=\frac{V_T\ln K}{R_2}---\left(5\right)$

As seen I _R2Has positive temperature coefficient (PTC).

Voltage on the R3 equals the voltage of D1, has negative temperature coefficient.Therefore the electric current on the R3 is a negative temperature parameter current:

$I_{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}3}=\frac{V_{D1}}{{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}}_3}=I_{S1}{\mathrm{<figure-callout\; id="1"\; label="e\; V\; D"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">e</figure-callout>}}^{V_D}---\left(6\right)$

M4, M5, M6, M10 breadth length ratio are identical, and the M12 breadth length ratio is its N ₁Doubly, the M11 breadth length ratio is its N ₂Doubly.Have according to the current mirror relation:

I _M12＝N ₁I _M6＝N ₁I _M5＝N ₁I _R2 (7)

I _M11＝N ₂I _M10＝N ₂(I _R3-I _M6)＝N ₂(I _R3-I _R2) (8)

M6 and M10 electric current sum equal the electric current on the R3, and the last electric current of M6 is a positive temperature coefficient (PTC), must be negative temperature coefficient so flow through the electric current of M10.The electric current I of the electric current output negative temperature coefficient of M11 mirror image M10 _M11, the electric current of M12 mirror image M6 obtains the electric current I of positive temperature coefficient (PTC) _M12, two electric currents can obtain electric current, the voltage reference of different temperature coefficients by stack on resistance R 4.Electric current on the R4 is:

$I_{\mathrm{<figure-callout\; id="4"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}4}=I_{M11}+I_{M12}=(N_1-N_2)I_{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}2}+N_2{I}_{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">R</figure-callout>}3}=(N_1-N_2)\frac{V_T\mathrm{<figure-callout\; id="2"\; label="ln\; K\; R"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">ln</figure-callout>}K}{R_{}}+N_2{I}_{S1}{\mathrm{<figure-callout\; id="1"\; label="e\; V\; D"\; filenames="S2007101884921E00011.png"\; state="\{\{state\}\}">e</figure-callout>}}^{V_D}---\left(9\right)$

The all right resistance in series potential-divider network of R4 is exported different magnitudes of voltage simultaneously.

About operating voltage, because circuit structure is simple,, guarantee metal-oxide-semiconductor and diode current flow operate as normal from improved auto bias circuit, can estimate required operating voltage can be for about 1.5V.

Claims (5)

1. the circuit of the adjustable positive and negative or zero-temperature coefficient electrical current of output, voltage reference, it is characterized in that, comprise: start-up circuit, positive and negative temperature coefficient current generating circuit, feedback stability and negative temperature parameter current derived circuit, the current reference that temperature coefficient is adjustable, voltage reference combiner circuit; Described start-up circuit is positive and negative temperature coefficient current generating circuit, and the positive temperature coefficient (PTC) electric current output in the current reference that temperature coefficient is adjustable, the voltage reference combiner circuit provides the startup bias voltage; Described positive and negative temperature coefficient current generating circuit produces the electric current with positive and negative temperature coefficient; Described feedback stability and negative temperature parameter current derived circuit are stablized current mirror and the heavy gate bias voltage of electric current in the positive and negative temperature coefficient current generating circuit, participate in the electric current of synthetic negative temperature coefficient; The current reference that described temperature coefficient is adjustable, voltage reference combiner circuit output two-way electric current, one the tunnel is the positive temperature coefficient (PTC) electric current, another road is a negative temperature parameter current, positive and negative temperature coefficient electric current is superposeed by resistance, produce the current reference or the voltage reference of zero-temperature coefficient or different temperature coefficients; The input end of the positive and negative temperature coefficient current generating circuit of output termination of described start-up circuit; First output terminal of positive and negative temperature coefficient current generating circuit connects the input of feedback stability and negative temperature parameter current derived circuit, the current reference that its second and third output terminal jointing temp coefficient is adjustable, voltage reference combiner circuit; The output of feedback stability and negative temperature parameter current derived circuit feeds back to positive and negative temperature coefficient current generating circuit again; Positive and negative or the zero-temperature coefficient electrical current benchmark of the current reference that temperature coefficient is adjustable, voltage reference combiner circuit output, voltage reference.

2. a kind of output according to claim 1 can be aligned, bear or zero-temperature coefficient electrical current, the circuit of voltage reference, it is characterized in that described start-up circuit is: two PMOS transistor M1 and M2 constitute current mirror, its source electrode is connected with power supply, its grid links to each other with the drain electrode of a PMOS transistor M3, also link to each other with resistance R 1 one ends and PMOS transistor M1 drain electrode, resistance R 1 other end ground connection VSS, PMOS transistor M2 drain electrode connects just described, negative temperature parameter current produces nmos pass transistor M7 in the circuit, the grid of M8 and M9, PMOS transistor M3 source electrode connects power supply, and its grid connects just described, negative temperature parameter current produces circuit PMOS transistor M4, M5, the grid of M6 and described electric current, the grid of PMOS transistor M12 in the voltage reference combiner circuit.

3. a kind of output according to claim 1 can be aligned, bear or zero-temperature coefficient electrical current, the circuit of voltage reference, it is characterized in that, just described, negative temperature parameter current produces circuit: PMOS transistor M4, the current mirror that M5 and M6 common gate constitute, nmos pass transistor M7, the electric current that M8 and M9 common gate constitute is heavy forms improved automatic biasing structure with PMOS transistor M10, be divided into three the tunnel, the first via is by transistor M4, M7 and diode D1 constitute, transistor M4 source electrode connects power supply, transistor M4 grid, leakage is connected to the drain electrode of transistor M7, transistor M7 source electrode connects diode D1 anode, diode D1 plus earth VSS; The second road PMOS transistor M5, nmos pass transistor M8, resistance R 2 and diode D2 constitute, PMOS transistor M5 source electrode connects power supply, drain electrode connects the grid that PMOS transistor M10, M11 in feedback and the output circuit are also received in nmos pass transistor M8 drain electrode, M8 source electrode connecting resistance R2 one end, resistance R 2 another terminating diode D2 anodes, diode D2 plus earth VSS, the electric current of generation positive temperature coefficient (PTC) on resistance R 2; Third Road is made of PMOS transistor M6, nmos pass transistor M9 and resistance R 3, PMOS transistor M6 source electrode connects power supply, drain electrode connects nmos pass transistor M9 grid and drain electrode, nmos pass transistor M9 source electrode connecting resistance R3 one end, also receive the drain electrode of PMOS transistor M10, resistance R 3 other ends are linked ground, produce negative temperature parameter current on the resistance R 3.

4. a kind of circuit of exporting adjustable positive and negative or zero-temperature coefficient electrical current, voltage reference according to claim 1, it is characterized in that, described feedback stability and negative temperature parameter current derived circuit are: be made of a PMOS pipe M10, PMOS pipe M10 source electrode connects power supply, its grid connects PMOS pipe M5 and nmos pass transistor M8 drain electrode, the source electrode of PMOS pipe M10 drain electrode connecting resistance R3 one end and nmos pass transistor M9.

5. a kind of circuit of exporting adjustable positive and negative or zero-temperature coefficient electrical current, voltage reference according to claim 1, it is characterized in that, the current reference that described temperature coefficient is adjustable, voltage reference combiner circuit are: two PMOS manage M11 and M12, and the source electrode of PMOS pipe M11 and M12 connects power supply; PMOS pipe M11 grid connects PMOS pipe M10 grid, PMOS pipe M11 mirror image PMOS pipe M10 synthesizes negative temperature parameter current and manages M11 drain electrode output negative temperature parameter current from PMOS, PMOS pipe M12 grid connects the positive temperature coefficient (PTC) electric current that produces on the grid mirror image resistance R 2 of M5, resistance R 4 one ends connect the drain electrode of PMOS pipe M11 and M12, resistance R 4 its other end ground connection VSS.

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