CN100399224C - Current source with very high output impedance - Google Patents

Abstract

The present invention relates to a current source with very high output impedance, which comprises a current source generating circuit and an equivalent negative resistance generating circuit, wherein the current source generating circuit can be composed of all current source circuits, such as a Cascode current mirror, a Wilson current mirror, a Widlar current source, etc., and is used for generating positive resistance and a reference current; the equivalent negative resistance generating circuit is composed of a PMOS tube, an NMOS tube and an amplifier which are connected by a grid leak in a short mode, and is used for generating equivalent negative resistance. The absolute value of the equivalent negative resistance is a little greater than the positive resistance value through design, and the equivalent negative resistance and the positive resistance are connected in parallel, so that the very high output impedance is obtained, and the value of the very high output impedance can reach an order of magnitude of 10<9> ohms. The output current of, the current source with very high output impedance, which is provided by the present invention, has good frequency characteristic and good temperature characteristic.

Description

A kind of current source with high output impedance

Technical field

The invention belongs to electronic technology field, be specifically related to the current source technology in the power technique fields.

Background technology

Current source is the variation along with voltage, and its output current keeps constant a kind of circuit, and it is the important composition part in the Analogous Integrated Electronic Circuits, and demand is widely arranged in Analogous Integrated Electronic Circuits.For electric current, not loss on long metal wire, voltage then has loss, so in having the complicated mimic channel of long metal wire, current source is more welcome.U.S. John Wiley﹠amp; " the Analysis and Design of Analog IntegratedCircuits " (4 that writes by people such as Paul R.Gray that Sons company calendar year 2001 publishes ^ThEdition) chapter 4 has been introduced various types of current sources, and as this book was described, current source both can be made biasing element, also can serve as the active load of amplifier stage.Wherein, the output impedance of current source is the important parameter of current source circuit, and output impedance is high more, shows that the current source output current is stable more.Therefore, in the high precision integrated circuit, the design in high impedance current source is extremely important.And owing to being of wide application of contemporary electronic systems, environment is harsher, therefore requires reference current source can both work reliably in very wide temperature range (25 ℃～125 ℃) and very wide supply voltage range circuit.The general energy gap circuit that adopts is realized constant pressure source (referring to voltage source) in prior art, as K.N.Leung, P.K.T.Mok.A Sub-1-V15-ppm/ ℃ of CMOS bandgap voltage reference without requiring low threshold voltage device, IEEE Journal of Solid-State Circuits.2002,37 (4): 526～530.

Common current source circuit, its output impedance are about the megohm order of magnitude, and its electric current output is stable inadequately.In order to improve current source output impedance, a kind of method of routine is high resistance measurement R of polyphone on current source equivalence positive output impedance ro, makes total output impedance R _Out=r _o+ R (as shown in Figure 1).But can consume bigger voltage remaining like this, simultaneously, supply voltage be increased.

Actual current source circuit exists some problems, such as output impedance is big inadequately, and stable output current need could realize under high voltage etc.

Summary of the invention

The objective of the invention is to propose a kind of current source, simultaneously this current source less minimum that makes outputting current steadily (Vomin) that should have, well current stability and frequency response characteristic and very little temperature coefficient with high output impedance.

A kind of current source that the present invention proposes with high output impedance, comprise an electric current source generating circuit, it is characterized in that it comprises that also an equivalent negative resistance produces circuit, described equivalent negative resistance generation circuit and electric current source generating circuit are in parallel and produce high output impedance.Wherein, the electric current source generating circuit is used to produce a positive resistance and a reference current; Equivalent negative resistance produces circuit and is used to produce an equivalent negative resistance.Described electric current source generating circuit can be realized with all current mirrors and current source circuit.

The structure that technical scheme of the present invention comes down to utilize two very close positive negative resistances of absolute value to be in parallel realizes the high output impedance of current source.The output impedance of supposing the electric current source generating circuit is r _o, the equivalent resistance that equivalent negative resistance produces circuit is r ₂, then total output impedance after two circuit parallel connections $R_{\mathrm{out}}=\frac{r_o{r}_2}{{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="C20051002112200162.png,C20051002112200172.png"\; state="\{\{state\}\}">r</figure-callout>}}_0+{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="C20051002112200162.png,C20051002112200163.png"\; state="\{\{state\}\}">r</figure-callout>}}_2},$ By suitable calculating and setting | r ₂| be slightly larger than | r _o|, just can obtain the current source of high output impedance, its output impedance is R _Out

Wherein, producing the electric current source generating circuit of positive resistance and reference current, can be all current mirrors and current source circuits such as Cascode current mirror, Wilson current mirror and Widlar current source.

Wherein, the electric current source generating circuit can be realized with the Cascode current mirror, comprise:

(1) current reference source Iref1 is used to produce steady current, and one end and external power supply join, and the drain electrode of the other end and NMOS pipe M3 is joined.

(2) four NMOS pipe (M1, M2, M3 and M4) is used to constitute the cascode current mirror, to produce two electric currents.NMOS pipe M1 and M2 constitute mirrored transistor, and NMOS pipe M3 and M4 constitute mirrored transistor.The source ground of the nmos pass transistor of two mirror images (M1 and M2) wherein, its grid is connected to each other, and is connected to the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M3 is received in the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M4 is received in the drain electrode of NMOS pipe M2; The grid of the NMOS pipe (M3 and M4) of two other mirror image interconnects, and is connected to the drain electrode of NMOS pipe M3, and the drain electrode of NMOS pipe M3 connects additional power source by current reference source Iref1.

Wherein, the electric current source generating circuit can be realized with the Wilson current mirror, comprise:

(1) current reference source Iref1 is used to produce steady current, and one end and external power supply join, and the drain electrode of the other end and NMOS pipe M3 is joined.

(2) four NMOS pipe (M1, M2, M3 and M4) is used to constitute the Wilson current mirror, to produce two electric currents.NMOS pipe M1 and M2 constitute mirrored transistor, and NMOS pipe M3 and M4 constitute mirrored transistor.The source ground of the nmos pass transistor of two mirror images (M1 and M2) wherein, its grid is connected to each other, and is connected to the drain electrode of NMOS pipe M2, and the source electrode of NMOS pipe M3 is received in the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M4 is received in the drain electrode of NMOS pipe M2; The grid of the NMOS pipe (M3 and M4) of two other mirror image interconnects, and is connected to the drain electrode of NMOS pipe M3, and the drain electrode of NMOS pipe M3 connects additional power source by current reference source Iref1.

Wherein, the electric current source generating circuit can be realized with the Widlar current source, comprise:

(1) two nmos pass transistor (M1 and M2) and two resistance (R1 and R2), the grid of two NMOS pipes is connected to each other, and is connected to the drain electrode of NMOS pipe M1, the source ground of NMOS pipe M1, the drain electrode of NMOS pipe M1 is connected with external power supply by resistance R 1; The source electrode of NMOS pipe M2 is connected with ground by resistance R 2.

Equivalent negative resistance of the present invention produces circuit and comprises:

(1) PMOS pipe M5, the grid of PMOS pipe M5 and drain electrode short circuit form the diode type of attachment, and its drain electrode is connected on the drain electrode of NMOS pipe M6.

(2) NMOS pipe M6 are used for providing bias current to PMOS pipe M5.The grid of NMOS pipe M6 meets biasing voltage signal Vbias1, and its source electrode is connected with ground, and the drain electrode of NMOS pipe M6 is connected with the drain electrode of NMOS pipe M5.

(3) cmos amplifier A1 are used for converting the drain-source equiva lent impedance that PMOS manages M5 to equivalent negative resistance that equivalent negative resistance produces circuit.The source electrode of the input end of cmos amplifier A1 and PMOS pipe M5 joins, and grid and the drain electrode of the output terminal of cmos amplifier A1 and PMOS pipe M5 are joined.

Wherein, the cmos amplifier A1 in the equivalent negative resistance generation circuit can comprise:

A PMOS pipe M7 and a NMOS pipe M10 constitute first order amplifier, are used for that signal is carried out the first order and amplify; A PMOS pipe M11 and a NMOS pipe M8 constitute second level amplifier, are used for that signal is carried out the second level and amplify; Two NMOS pipes (M9 and M12) constitute third level amplifier; The grid of PMOS pipe M7 is as the input end of cmos amplifier A1, and its source electrode and additional power source join, and its drain electrode is joined with the grid that NMOS manages M8; NMOS manages the grid and drain electrode short circuit of M10, and joins with the drain electrode of PMOS pipe M7, and the source electrode of NMOS pipe M10 is connected with ground; The grid of PMOS pipe M11 and drain electrode short circuit, and join with the drain electrode of NMOS pipe M8 and the grid of NMOS pipe M9 simultaneously; The grid of NMOS pipe M8 joins with the drain electrode of PMOS pipe M7 and the drain electrode of NMOS pipe M10 simultaneously, and the drain electrode of NMOS pipe M8 is joined with the drain electrode of PMOS pipe M11 and the grid of NMOS pipe M9 simultaneously, and the source electrode of NMOS pipe M8 is connected with ground; The source electrode of NMOS pipe M9 is connected with the drain electrode of NMOS pipe M12, and drain electrode and the additional power source of NMOS pipe M9 join; NMOS pipe M12 grid meet biasing voltage signal Vbias1, the source electrode of NMOS pipe M12 joins with ground.

Equivalent negative resistance generation circuit of the present invention is in parallel with the electric current source generating circuit and is connected, to produce the high output impedance of whole current source.Its concrete annexation is:

1, if the electric current source generating circuit is the electric current source generating circuit based on the Cascode current mirror, then the annexation of the two is: the drain electrode of NMOS pipe M4 links to each other with the source electrode of PMOS pipe M5 and the grid of PMOS pipe M7 simultaneously; The output terminal of whole current source is the drain electrode of NMOS pipe M4, the source electrode of PMOS pipe M5 and the common tie point that PMOS manages the grid of M7.

2, if the electric current source generating circuit is the electric current source generating circuit based on the Wilson current mirror, then the annexation of the two is: the drain electrode of NMOS pipe M4 links to each other with the source electrode of PMOS pipe M5 and the grid of PMOS pipe M7 simultaneously; The output terminal of whole current source is the drain electrode of NMOS pipe M4, the source electrode of PMOS pipe M5 and the common tie point that PMOS manages the grid of M7.

3, if the electric current source generating circuit is the Widlar current source, then the annexation of the two is: the drain electrode of NMOS pipe M2 links to each other with the source electrode of PMOS pipe M5 and the grid of PMOS pipe M7 simultaneously; The output terminal of whole current source is the drain electrode of NMOS pipe M2, the source electrode of PMOS pipe M5 and the common tie point that PMOS manages the grid of M7.

Need to prove that the equivalent negative resistance described in the present invention is not made of special material or device, but realize by common cmos amplifier circuit and MOS transistor.

A kind of current source circuit with high output impedance of the present invention has the following advantages:

1, greatly increased the output impedance of current source, made output current more stable with the variation of output voltage.

2, improved Vomin, made output current under lower voltage, just can reach stable.As Fig. 9, can find out from the Vomin comparison diagram of the output current of Wilson current mirror, produce circuit, Vomin ≈ 2.105V if do not add equivalent negative resistance; But after adding equivalent negative resistance generation circuit, Vomin has reduced as can be seen, Vomin ≈ 1.483V.As Figure 10, can find out from the Vomin comparison diagram of the output current of Cascode current mirror, produce circuit, Vomin ≈ 2.100V if do not add equivalent negative resistance; But after adding equivalent negative resistance generation circuit, Vomin has reduced as can be seen, Vomin ≈ 1.465V.

3, electric current source generating circuit of the present invention is made of current mirrors such as common Cascode current mirror, Wilson current mirror and Widlar current source and current source circuit, and simple in structure, chip occupying area is little, and power consumed is low.

4, the high output impedance circuit structure of invention proposition makes the outputting current steadily of current source fine, and its frequency response characteristic is good.

5, the temperature coefficient of the output current of the high output impedance current source of the present invention's proposition is very little, and temperature coefficient (40 ℃～+ 145 ℃) in very wide range of temperature is 10.6ppm/ ℃.

Description of drawings:

Fig. 1 is the electrical block diagram that routine has the current source of high output impedance.

Fig. 2 is a kind of structured flowchart with current source of high output impedance of the present invention.

Fig. 3 is the current source circuit schematic diagram with high output impedance that a kind of Cascode of utilization current mirror is made the electric current source generating circuit.

Fig. 4 is the current source circuit schematic diagram with high output impedance that a kind of Wilson of utilization current mirror is made the electric current source generating circuit.

Fig. 5 is the current source circuit schematic diagram with high output impedance that a kind of Widlar of utilization current source is made the electric current source generating circuit.

Fig. 6 is the circuit diagram that equivalent negative resistance produces cmos amplifier A1 in the circuit.

Fig. 7 is the relation curve of the output current of a kind of Cascode of utilization current mirror current source with high output impedance of making the electric current source generating circuit with output voltage.Curve 1 is the relation of the output current of reference current source with output voltage, and curve 2 is the relation of output current of the present invention with output voltage.

Fig. 8 is the relation curve of the output current of a kind of Wilson of utilization current mirror current source with high output impedance of making the electric current source generating circuit with output voltage.Curve 1 is the relation of the output current of reference current source with output voltage, and curve 3 is the relation of output current of the present invention with output voltage.

Fig. 9 is the comparison of the Vomin of the Vomin of output current of a kind of Cascode of utilization current mirror current source with high output impedance of making the electric current source generating circuit and Cascode current mirror output current.Wherein, curve 5 is the output current of Cascode current mirror, and curve 4 is the output current of current source of the present invention.

Figure 10 is the comparison of the Vomin of the Vomin of output current of a kind of Wilson of utilization current mirror current source with high output impedance of making the electric current source generating circuit and Wilson current mirror output current.Wherein, curve 7 is the output current of Wilson current mirror, and curve 6 is the output current of current source of the present invention.

Figure 11 is the frequency characteristic of the output current of a kind of Cascode of utilization current mirror current source with high output impedance of making the electric current source generating circuit.

Figure 12 is the frequency characteristic of the output current of a kind of Wilson of utilization current mirror current source with high output impedance of making the electric current source generating circuit.

Figure 13 is the temperature characteristics of the output current of a kind of Cascode of utilization current mirror current source with high output impedance of making the electric current source generating circuit.

Figure 14 is the temperature characteristics of the output current of a kind of Wilson of utilization current mirror current source with high output impedance of making the electric current source generating circuit.

Embodiment

The negative resistance technology of utilizing that the present invention proposes realizes the current source of high output impedance, and its structured flowchart comprises that a reference current source circuit and a negative resistance produce circuit as shown in Figure 2.Reference current source circuit wherein is used to produce a positive resistance and a reference current, is used to realize big resistance.This reference current source can be realized with all current mirrors and current source circuit.

At this is the example principle of specification with wherein cascode current mirroring circuit only:

The electric current source generating circuit is realized with the Cascode current mirror, being comprised:

(1) current reference source Iref1 is used to produce steady current, and one end and external power supply join, and the drain electrode of the other end and NMOS pipe M3 is joined.

(2) four NMOS pipe (M1, M2, M3 and M4) is used to constitute the cascode current mirror, to produce two electric currents.NMOS pipe M1 and M2 constitute mirrored transistor, and NMOS pipe M3 and M4 constitute mirrored transistor.The source ground of the nmos pass transistor of two mirror images (M1 and M2) wherein, its grid is connected to each other, and is connected to the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M3 is received in the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M4 is received in the drain electrode of NMOS pipe M2; The grid of the NMOS pipe (M3 and M4) of two other mirror image interconnects, and is connected to the drain electrode of NMOS pipe M3, and the end of reference source Iref1 is received in the drain electrode of NMOS pipe M3.

Negative resistance wherein produces circuit and comprises:

(1) PMOS pipe M5, grid and the source shorted of PMOS pipe M5 form the diode type of attachment, and its drain electrode is connected on the drain electrode of NMOS pipe M6.

(2) NMOS pipe M6 are used for providing bias current to PMOS pipe M5.The grid of NMOS pipe M6 meets biasing voltage signal Vbias1, and its source electrode is connected with ground, and the drain electrode of NMOS pipe M6 is connected with the drain electrode of NMOS pipe M5.

(3) cmos amplifier A1 is used for converting the drain-source equiva lent impedance that PMOS manages M5 to equivalent negative resistance that equivalent negative resistance produces circuit.The source electrode of the input end of cmos amplifier A1 and PMOS pipe M5 joins, and grid and the drain electrode of the output terminal of cmos amplifier A1 and PMOS pipe M5 are joined.

Wherein, the cmos amplifier A1 in the equivalent negative resistance generation circuit comprises:

A PMOS pipe M7 and a NMOS pipe M10 constitute first order amplifier, are used for that signal is carried out the first order and amplify; A PMOS pipe M11 and a NMOS pipe M8 constitute second level amplifier, are used for that signal is carried out the second level and amplify; Two NMOS pipes (M9 and M12) constitute third level amplifier; The grid of PMOS pipe M7 is as the input end of cmos amplifier A1, and its source electrode and additional power source join, and its drain electrode is joined with the grid that NMOS manages M8; NMOS manages the grid and drain electrode short circuit of M10, and joins with the drain electrode of PMOS pipe M7, and the source electrode of NMOS pipe M10 is connected with ground; The grid of PMOS pipe M11 and drain electrode short circuit, and join with the drain electrode of NMOS pipe M8 and the grid of NMOS pipe M9 simultaneously; The grid of NMOS pipe M8 joins with the drain electrode of PMOS pipe M7 and the drain electrode of NMOS pipe M10 simultaneously, and the drain electrode of NMOS pipe M8 is joined with the drain electrode of PMOS pipe M11 and the grid of NMOS pipe M9 simultaneously, and the source electrode of NMOS pipe M8 is connected with ground; The source electrode of NMOS pipe M9 is connected with the drain electrode of NMOS pipe M12, and drain electrode and the additional power source of NMOS pipe M9 join; The grid of NMOS pipe M12 meets biasing voltage signal Vbias1, and the source electrode of NMOS pipe M12 joins with ground.

Described electric current source generating circuit with the annexation that equivalent negative resistance produces circuit is: the drain electrode of NMOS pipe M4 links to each other with the source electrode of PMOS pipe M5 and the grid of PMOS pipe M7 simultaneously; The output terminal of whole current source is the drain electrode of NMOS pipe M4, the source electrode of PMOS pipe M5 and the common tie point that PMOS manages the grid of M7.

Above-mentioned embodiment produces the principle of high output impedance:

(1). the method for designing of the current source of the high output impedance of the electronegative resistance that the present invention proposes is to utilize current source equivalence positive output impedance R _CmEquivalent negative resistance R in parallel _GainSo:

$R_{\mathrm{out}}=\frac{R_{\mathrm{cm}}{R}_{\mathrm{gain}}}{R_{\mathrm{cm}}+R_{\mathrm{gain}}}---\left(1\right)$

R wherein _CmBe positive resistance, R _GainBe equivalent negative resistance.Described | R _Gain| be slightly larger than | R _Cm|, then can obtain the very high current source R of resistance _Out

(2). the cascode current mirror in the above-mentioned electric current source generating circuit as shown in Figure 3, its ac small signal output impedance is determined by following formula:

R _cm≈g _m4·R _ds4·R _ds2 (1)

(3). grid and the drain electrode of PMOS among Fig. 3 pipe M5 link to each other, and the grid of PMOS pipe M5 links to each other with the leakage that NMOS manages M6 with drain electrode, and the grid that NMOS manages M6 is connected on biasing voltage signal contact V _Biasl, its source electrode is connected with ground, and NMOS pipe M6 is used for providing bias current to PMOS pipe M5.The equivalent output impedance of PMOS pipe M5 is R _Ds5, promptly negative feedback resistor is R _Ds5Cmos amplifier A1 shown in Fig. 4 amplifies the cmos amplifier of being formed by three grades.The first order is the reverse amplifier stage of common source, its voltage gain A _V1≈-g _M7/ g _M10The second level also is the reverse amplifier stage of common source, its voltage gain A _V2≈-g _M8/ g _M11The third level is the forward amplifier stage of common leakage, its voltage gain A _V3≈ g _M9/ (g _M9+ g _Mb9).Therefore the total voltage gain of operational amplifier (A1) is:

$A_V=A_{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="C20051002112200151.png,C20051002112200162.png"\; state="\{\{state\}\}">V</figure-callout>}1}\&CenterDot;A_{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C20051002112200162.png,C20051002112200163.png"\; state="\{\{state\}\}">V</figure-callout>}2}\&CenterDot;A_{\mathrm{<figure-callout\; id="3"\; label="V"\; filenames="C20051002112200173.png"\; state="\{\{state\}\}">V</figure-callout>}3}=(-\frac{g_{m7}}{g_{m10}})(-\frac{g_{m8}}{g_{m11}})\left(\frac{g_{m9}}{g_{m9}+g_{\mathrm{mb}9}}\right)=\frac{g_{m7}{g}_{m8}{g}_{m9}}{g_{m10}{g}_{m11}(g_{m9}+g_{\mathrm{mb}9})}---\left(2\right)$

As shown in Figure 3, from the source electrode of PMOS pipe (M5) see into equivalent resistance be:

$R_{\mathrm{gain}}=\frac{{\mathrm{<figure-callout\; id="5"\; label="R\; ds"\; filenames="C20051002112200162.png,C20051002112200172.png"\; state="\{\{state\}\}">R</figure-callout>}}_{\mathrm{ds}}}{1-A_V}---\left(3\right)$

(4). at the output current I of the current source of high output impedance of the present invention _OutThe equivalent resistance that port is seen is:

$R_{\mathrm{eq}}=R_{\mathrm{out}}=R_{\mathrm{cm}}//R_{\mathrm{gain}}=\frac{R_{\mathrm{cm}}\&CenterDot;R_{\mathrm{gain}}}{R_{\mathrm{cm}}+R_{\mathrm{gain}}}---\left(4\right)$

The gain A v that makes operational amplifier by parameter designing is slightly greater than 1, like this R _GainBe exactly an equivalent negative resistance.Design R _GainAbsolute value slightly greater than R _CmAbsolute value, so just make R _EqDenominator R _Cm+ R _GainBecome slightly less than 0, thereby obtain a very large positive resistance R _Eq, the high output impedance purpose of realization current source is largely improved the outputting current steadily performance of current source.The output impedance R of the Cascode current mirroring circuit that the present invention is designed _Cm=30.1552M, equivalent negative resistance produces the output impedance R of circuit _Gain=-30.7058M, total output impedance R in the high impedance current source of the present invention's design _Eq=1.6817G.

(5). the output current characteristic curve of the high output impedance current source of making the electric current source generating circuit with the Cascode current mirror of the present invention is as shown in Figure 7.In the comparison according to the Vomin of the output current of the current source of the high output impedance of making the electric current source generating circuit with the Cascode current mirror shown in Figure 8, do not add the Vomin ≈ 2.100V of negative-resistance-compensated pure Cascode current mirror but after adding negative-resistance-compensated circuit, the Vomin of the high output impedance current source of the present invention design is reduced to Vomin ≈ 1.465V.

The frequency response characteristic of the output current of the high output impedance current source of making the electric current source generating circuit with the Cascode current mirror of the present invention as shown in figure 11, frequency span is 1.04GHz.

The output current of the high output impedance current source of making the electric current source generating circuit with the Cascode current mirror of the present invention and the relation of temperature, as shown in figure 13.In-40 ℃～145 ℃ temperature ranges, the temperature coefficient of electric current only is 10.6ppm/ ℃, and its temperature characterisitic is fine.

The output current characteristic curve of the high output impedance current source of making the electric current source generating circuit with the Wilson current mirror of the present invention as shown in Figure 8.In the comparison according to the Vomin of the output current of the current source of the high output impedance of making the electric current source generating circuit with the Wilson current mirror shown in Figure 10, do not add the Vomin ≈ 2.105V of negative-resistance-compensated pure Wilson current mirror; But after adding negative-resistance-compensated circuit, the Vomin of the high output impedance current source of the present invention's design is reduced to Vomin ≈ 1.483V.

The frequency response characteristic of the output current of the high output impedance current source of making the electric current source generating circuit with the Wilson current mirror of the present invention as shown in figure 12, frequency span is 1.03GHz.

The output current of the high output impedance current source of making the electric current source generating circuit with the Wilson current mirror of the present invention and the relation of temperature, as shown in figure 14.In-40 ℃～145 ℃ temperature ranges, the temperature coefficient of electric current only is 10.6ppm/ ℃, and its temperature characterisitic is fine.

Claims (9)

1. current source with high output impedance, comprise an electric current source generating circuit, it is characterized in that, it comprises that also an equivalent negative resistance produces circuit, described equivalent negative resistance produces circuit and the electric current source generating circuit is in parallel, and the absolute value that described equivalent negative resistance produces the equivalent negative resistance that circuit produced is slightly larger than the positive resistance that the electric current source generating circuit is produced.

2. a kind of current source with high output impedance according to claim 1 is characterized in that, described equivalent negative resistance produces circuit and comprises PMOS pipe M5, a NMOS pipe M6 and an amplifier, and the voltage gain of described amplifier is slightly larger than 1; Its annexation is: the grid of PMOS pipe M5 and drain electrode short circuit, and its drain electrode is connected on the drain electrode of NMOS pipe M6; The grid of NMOS pipe M6 meets biasing voltage signal Vbias1, and its source electrode is connected with ground, and the drain electrode of NMOS pipe M6 is connected with the drain electrode of NMOS pipe M5; The source electrode of amplifier input terminal Vi and PMOS pipe M5 joins, and grid and the drain electrode of the output end vo of amplifier and PMOS pipe M5 are joined.

3. a kind of current source with high output impedance according to claim 2 is characterized in that described amplifier is cmos amplifier A1, and described cmos amplifier A1 comprises a PMOS pipe M7 and the first order amplifier that NMOS pipe M10 constitutes; A PMOS pipe M11 and the second level amplifier that NMOS pipe M8 constitutes; Two NMOS manage the third level amplifier of M9 and M12 formation; The grid of PMOS pipe M7 is as the input end of cmos amplifier A1, and its source electrode and additional power source join, and its drain electrode is joined with the grid that NMOS manages M8; NMOS manages the grid and drain electrode short circuit of M10, and joins with the drain electrode of PMOS pipe M7, and the source electrode of NMOS pipe M10 is connected with ground; The grid of PMOS pipe M11 and drain electrode short circuit, and join with the drain electrode of NMOS pipe M8 and the grid of NMOS pipe M9 simultaneously; The grid of NMOS pipe M8 joins with the drain electrode of PMOS pipe M7 and the drain electrode of NMOS pipe M10 simultaneously, and the drain electrode of NMOS pipe M8 is joined with the drain electrode of PMOS pipe M11 and the grid of NMOS pipe M9 simultaneously, and the source electrode of NMOS pipe M8 is connected with ground; The source electrode of NMOS pipe M9 is connected with the drain electrode of NMOS pipe M12, and drain electrode and the additional power source of NMOS pipe M9 join; The grid of NMOS pipe M12 meets biasing voltage signal Vbias1, and the source electrode of NMOS pipe M12 joins with ground.

4. a kind of current source according to claim 1 with high output impedance, it is characterized in that, described electric current source generating circuit is the Cascode current mirror, described Cascode current mirror is made of four NMOS pipe M1, M2, M3 and M4 and a current reference source Iref1, NMOS pipe M1 and NMOS pipe M2 constitute mirrored transistor, and NMOS pipe M3 and NMOS pipe M4 constitute mirrored transistor; Wherein the nmos pass transistor M1 of two mirror images and the source ground of M2, its grid is connected to each other, and is connected to the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M3 is received in the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M4 is received in the drain electrode of NMOS pipe M2; The NMOS pipe M3 of two other mirror image and the grid of M4 interconnect, and are connected to the drain electrode of NMOS pipe M3, and the drain electrode of NMOS pipe M3 connects additional power source by current reference source Iref1.

5. a kind of current source according to claim 1 with high output impedance, it is characterized in that, described electric current source generating circuit is the Wilson current mirror, described Wilson current mirror is made of four NMOS pipe M1, M2, M3 and M4 and a current reference source Iref1, NMOS pipe M1 and NMOS pipe M2 constitute mirrored transistor, and NMOS pipe M3 and NMOS pipe M4 constitute mirrored transistor; Wherein the nmos pass transistor M1 of two mirror images and the source ground of M2, its grid is connected to each other, and is connected to the drain electrode of NMOS pipe M2, and the source electrode of NMOS pipe M3 is received in the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M4 is received in the drain electrode of NMOS pipe M2; The NMOS pipe M3 of two other mirror image and the grid of M4 interconnect, and are connected to the drain electrode of NMOS pipe M3, and the drain electrode of NMOS pipe M3 connects additional power source by current reference source Iref1.

6. a kind of current source according to claim 1 with high output impedance, it is characterized in that, described electric current source generating circuit is the Widlar current source, described Widlar current source is made of two nmos pass transistor M1, M2 and two resistance R 1, R2, the grid of two NMOS pipes M1, M2 is connected to each other, and be connected to the drain electrode of NMOS pipe M1, the source ground of NMOS pipe M1, the drain electrode of NMOS pipe M1 is connected with external power supply by resistance R 1; The source electrode of NMOS pipe M2 is connected with ground by resistance R 2.

7. a kind of current source according to claim 3 with high output impedance, it is characterized in that, described electric current source generating circuit is the Cascode current mirror, described Cascode current mirror is made of four NMOS pipe M1, M2, M3 and M4 and a current reference source Iref1, NMOS pipe M1 and NMOS pipe M2 constitute mirrored transistor, and NMOS pipe M3 and NMOS pipe M4 constitute mirrored transistor; Wherein the nmos pass transistor M1 of two mirror images and the source ground of M2, its grid is connected to each other, and is connected to the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M3 is received in the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M4 is received in the drain electrode of NMOS pipe M2; The NMOS pipe M3 of two other mirror image and the grid of M4 interconnect, and are connected to the drain electrode of NMOS pipe M3, and the drain electrode of NMOS pipe M3 connects additional power source by current reference source Iref1;

The drain electrode of NMOS pipe M4 links to each other with the source electrode of PMOS pipe M5 and the grid of PMOS pipe M7 simultaneously; The output terminal of whole current source is the drain electrode of NMOS pipe M4, the source electrode of PMOS pipe M5 and the common tie point that PMOS manages the grid of M7.

8. a kind of current source according to claim 3 with high output impedance, it is characterized in that, described electric current source generating circuit is the Wilson current mirror, described Wilson current mirror is made of four NMOS pipe M1, M2, M3 and M4 and a current reference source Iref1, NMOS pipe M1 and NMOS pipe M2 constitute mirrored transistor, and NMOS pipe M3 and NMOS pipe M4 constitute mirrored transistor; Wherein the nmos pass transistor M1 of two mirror images and the source ground of M2, its grid is connected to each other, and is connected to the drain electrode of NMOS pipe M2, and the source electrode of NMOS pipe M3 is received in the drain electrode of NMOS pipe M1, and the source electrode of NMOS pipe M4 is received in the drain electrode of NMOS pipe M2; The NMOS pipe M3 of two other mirror image and the grid of M4 interconnect, and are connected to the drain electrode of NMOS pipe M3, and the drain electrode of NMOS pipe M3 connects additional power source by current reference source Iref1;

The drain electrode of NMOS pipe M4 links to each other with the source electrode of PMOS pipe M5 and the grid of PMOS pipe M7 simultaneously; The output terminal of whole current source is the drain electrode of NMOS pipe M4, the source electrode of PMOS pipe M5 and the common tie point that PMOS manages the grid of M7.

9. according to a kind of current source of claim 3 with high output impedance, it is characterized in that, described electric current source generating circuit is the Widlar current source, described Widlar current source is made of two nmos pass transistor M1, M2 and two resistance R 1, R2, the grid of two NMOS pipes M1, M2 is connected to each other, and be connected to the drain electrode of NMOS pipe M1, the source ground of NMOS pipe M1, the drain electrode of NMOS pipe M1 is connected with external power supply by resistance R 1; The source electrode of NMOS pipe M2 is connected with ground by resistance R 2;

The drain electrode of NMOS pipe M2 links to each other with the source electrode of PMOS pipe M5 and the grid of PMOS pipe M7 simultaneously; The output terminal of whole current source is the drain electrode of NMOS pipe M2, the source electrode of PMOS pipe M5 and the common tie point that PMOS manages the grid of M7.

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