CN114879801A - Current generation circuit with adjustable temperature coefficient - Google Patents

Abstract

The invention discloses a temperature coefficient adjustable current generating circuit, which has a larger current temperature coefficient adjusting range and can improve the accuracy of the generated current, and comprises a voltage-to-current module and a temperature coefficient adjusting module, wherein one end of the voltage-to-current module is connected with a band gap reference voltage source, the other end of the voltage-to-current module is connected with one end of the temperature coefficient adjusting module, and the other end of the temperature coefficient adjusting module is a current output end; the voltage-to-current module is used for converting the voltage of the band-gap reference voltage source into a first temperature coefficient current and carrying out primary adjustment on the magnitude of the first temperature coefficient current to obtain a primary adjustment current; the temperature coefficient adjusting module is used for adjusting the temperature coefficient of the primary adjusting current and compensating the size of the primary adjusting current; and the other end of the temperature coefficient adjusting module outputs a second temperature coefficient current after the temperature coefficient is adjusted and the current magnitude is compensated.

Description

A current generating circuit with adjustable temperature coefficient

technical field

The invention relates to the technical field of integrated circuits, in particular to a current generating circuit with an adjustable temperature coefficient.

Background technique

In the process of chip design, the circuit is easily affected by the change of PVT. The change of PVT mainly refers to the change of chip technology, voltage and temperature. In the traditional bias current generation circuit, the change of PVT will not only lead to the change of the temperature coefficient and size of the bias current, Moreover, it is easy to cause the deterioration of the gain and linearity of the bias current circuit, thereby affecting the stability of the related circuit performance. A typical situation of a wide temperature range circuit is that the electrical performance of amplifiers, especially dynamic amplifiers, varies greatly with temperature under advanced process conditions, and changes in chip temperature will lead to deterioration of electrical performance (such as chip operating stability, current size accuracy).

At present, the commonly used method to reduce the influence of PVT changes on the circuit is to adjust the temperature coefficient of the bias current to adapt to the temperature change. However, when the current temperature coefficient is adjusted in the prior art, the magnitude of the current will be proportionally amplified with the change of the current temperature coefficient. Or shrinking, resulting in reduced current stability and accuracy of the output of the bias current generation circuit, thereby affecting the stability of the entire chip operation. In order to prevent the current size from changing greatly and reducing the stability of the circuit, the adjustment range of the current temperature coefficient cannot be too large, but the limited adjustment range of the current temperature coefficient leads to a narrow application range of the entire current generation circuit, which cannot meet the wide temperature range circuit ( For example, the application requirements of dynamic amplifiers under advanced technology.

SUMMARY OF THE INVENTION

Aiming at the problems in the prior art that the adjustable range of the bias current temperature coefficient adjustment circuit is small, and the problem that the accuracy of the current size is reduced due to the change of the current temperature coefficient, the present invention provides a current with an adjustable temperature coefficient The generating circuit can expand the adjustment range of the current temperature coefficient, and at the same time can improve the accuracy of the generated current.

To achieve the above object, the present invention adopts the following technical solutions:

A current generation circuit with adjustable temperature coefficient, which includes a voltage-to-current module and a temperature-coefficient adjustment module, one end of the voltage-to-current module is connected to a bandgap reference voltage source, and the other end of the voltage-to-current module is connected to the temperature coefficient One end of the adjustment module, the other end of the temperature coefficient adjustment module is the current output end;

The voltage-to-current module is configured to convert the voltage of the bandgap reference voltage source into a first temperature coefficient current, and adjust the magnitude of the first temperature coefficient current once to obtain a primary adjustment current;

The temperature coefficient adjustment module is used to adjust the temperature coefficient of the primary adjustment current, and to compensate the size of the primary adjustment current;

The other end of the temperature coefficient adjustment module outputs the second temperature coefficient current after the temperature coefficient adjustment and current magnitude compensation.

It is further characterized in that,

The voltage-to-current module includes an operational amplifier, a first switch control unit, and a current temperature coefficient adjustment unit. The forward input end of the operational amplifier is connected to the bandgap reference voltage source, and the voltage of the bandgap reference voltage source is zero temperature coefficient voltage, the reverse input end of the operational amplifier is connected to one end of the current temperature coefficient adjustment unit, one end of the first switch control unit and the other end of the current temperature coefficient adjustment unit are both connected to one end of the temperature coefficient adjustment module, The operational amplifier and the current temperature coefficient adjustment unit are used to generate a first temperature coefficient current related to the temperature coefficient, the first switch control unit is used to adjust the current size of the first temperature coefficient current once, and the The first switch control unit includes a plurality of switches, and the switches are respectively controlled by the control voltage VBP and the control word TA<n:1>;

The first switch control unit includes N MOS transistors MP3 and N MOS transistors MP4, where N is a positive integer, the current temperature coefficient adjustment unit includes a MOS transistor MP1 and a resistor R1, and the output ends of the operational amplifier are respectively Connect one end of the resistor R1 and the gate of the MOS transistor MP1, the drain of the MOS transistor MP1 is connected to the drain and gate of the MOS transistor MP2 in the temperature coefficient adjustment module, and the source of the MOS transistor MP2 is respectively connected to N all The source of the MOS transistor MP3, the gate of the MOS transistor MP5 in the temperature coefficient adjustment module, the gates of the N MOS transistors MP4 are controlled by the control voltage VBP, the drain of the N MOS transistors MP4 and the N MOS transistors The drains of MP3 are connected in a one-to-one correspondence, the gate of the MOS transistor MP3 is controlled by the control word TA<n:1>, the source of the MOS transistor MP4 is connected to the MOS transistor MP5 and the MOS transistor MP7 in the temperature coefficient adjustment module , MP9, MP11 source;

The MOS transistors MP1 to MP4 are all PMOS transistors;

The temperature coefficient adjustment module includes a first current mirror to a fourth current mirror, a second switch control unit, and a third switch control unit, and the first current mirror is used to convert the power supply to the first current output by the current module. The temperature coefficient current is replicated in proportion to K1 and K2, the second current mirror and the third current mirror are used to replicate the current passing through the first current mirror in proportion to K5, and the first current mirror and the second switch control unit One end of the second current mirror is connected in sequence to form a first current branch, one end of the third current mirror, one end of the third switch control unit, and one end of the fourth current mirror are connected in sequence to form a second current branch, and the other end of the second current mirror is connected in sequence to form a second current branch. One end is connected to the other end of the third current mirror, the turn-on or turn-off of the first current branch is controlled by the second switch control unit, and the second current branch is controlled by the third switch control unit The turn-on or turn-off of the branch is controlled, and the other end of the fourth current mirror is the current output end, which is used to output the second temperature coefficient current after the temperature coefficient adjustment and current magnitude compensation. Several switches in the second switch control unit are controlled by the control word TC1<n:1>, and several switches in the third switch unit are controlled by the control word TC1<n:1>, the control voltages VBN1 and VBN2 respectively, and the control words are controlled by the control word TC1<n:1>. TC1<n:1> controls the switches in the second switch control unit to realize the temperature coefficient adjustment of the primary adjustment current. Through the control word TC1<n:1>, the control voltages VBN1 and VBN2, The control of the switch realizes the compensation of the current size of the primary adjustment current;

The first current mirror includes MOS transistors MP2, MOS transistors MP5 and MP7, the second current mirror branch includes MOS transistors MN1 to MN4, the third current mirror branch includes MOS transistors MP8 to MP11, and the third current mirror branch includes MOS transistors MP8 to MP11. The four current mirror branches include MOS transistors MN7-MN10, the second switch control unit includes N MOS transistors MP6, and the third switch control unit includes M MOS transistors MP24, M MOS transistors MN5, and M MOS transistors MN6, wherein M is a positive integer, the source of the MOS transistor MP5 is connected to the sources of the MOS transistors MP2, MP4, MP7, MP9, and MP11 respectively, and the drain of the MOS transistor MP5 is respectively connected to the drain of the MOS transistor MN1 , the gate and the gate of the MOS transistor MN3, the source of the MOS transistor MN1 is respectively connected to the gate of the MOS transistor MN2, the source and the gate of the MOS transistor MN4, the drain of the MOS transistor MP9 is respectively connected to the MOS transistor MP9 The gate, the gate of the MOS transistor MP11, the drain of the MOS transistor MP8, the gate of the MOS transistor MP8 is respectively connected to the source of the MOS transistor MP8, the gate of the MOS transistor MP10, and the source of the MOS transistor MN3, and the drain of the MOS transistor MN3 is connected to The drain of the MOS transistor MN4, the source of the MOS transistor MN2 are respectively connected to the source of the MOS transistor MN4, the source of the MOS transistors MN6, MN8 and MN10, and the drain of the MOS transistor MP11 is connected to the drain of the MOS transistor MP10. , the source of the MOS tube MP10 is connected to the source of M MOS tubes MP24, the source and gate of the MOS tube MN7 and the gate of the MOS tube MN9, and the drain of the MOS tube MP24 is connected in series with the MOS tubes MN5, MN6, M The gates of the MOS transistors MP6 are controlled by the control word TC1<n:1>, the gates of the MOS transistors MP24 are controlled by the control word TC1<n:1>, the M MOS transistors MN5 are controlled by the control voltage VBN1, The M MOS transistors MN6 are controlled by the control power supply VBN2, the drain of the MOS transistor MN7 is respectively connected to the drain and gate of the MOS transistor MN8 and the gate of the MOS transistor MN10, and the drain of the MOS transistor MN10 is connected to the MOS transistor MN9 drain, the source of the MOS transistor MN9 is the current output end;

The MOS transistors MP5 to MP11 and the MOS transistor MP24 are all PMOS transistors, and the MOS transistors MN1 to MN10 are all NMOS transistors.

A voltage-to-current method, which applies the above-mentioned voltage-to-current module, characterized in that the step of using the voltage-to-current module to convert a zero temperature coefficient voltage of a bandgap reference voltage source into a current includes: A1, zero temperature coefficient The temperature coefficient voltage is amplified by the operational amplifier to obtain the amplified current;

A2. The amplified current is converted by the current temperature coefficient adjustment unit to obtain the first temperature coefficient current;

A3. Control the switches in the first switch control unit through the control voltage VBP and the control word TA<n:1>, so as to realize the primary adjustment of the current size of the first temperature coefficient current, and obtain the primary adjustment current.

It is further characterized in that,

In step A2, the amplified current is compensated by the MOS transistor MP1 and the resistor R1 in the current temperature coefficient adjustment unit to generate a first temperature coefficient current related to the temperature coefficient of the resistor R1;

In step A3, the N MOS transistors MP4 and N MOS transistors MP3 in the first switch control unit are respectively controlled by the control voltage VBP and the control word TA<n:1>, and the first switch control unit controls the first temperature coefficient. The specific steps of adjusting the current include: when the first temperature coefficient current flows through the MOS transistor MP4, the gates of the N MOS transistors MP4 are controlled by the control voltage VBP, and at the same time, the gates of the N MOS transistors MP4 are controlled by the control word TA<n:1>. The gates of the N MOS transistors MP3 adjust the current size of the first temperature coefficient current once;

The specific steps of controlling the gate of the MOS transistor MP3 through the control word TA<n:1> include: A321. When n=0 and TA<n:1>=0, the MOS transistor MP3 of the corresponding bit is closed, and the corresponding bit The current of the MOS tube MP4 enters the branch of the MOS tube MP1 through the MOS tube MP3 to realize the addition of the current of the MOS tube MP1 and the current of the MOS tube MP2; A322, when n=1, TA<n:1>=1, the MOS tube MP3 is turned off, and the current of the branch from the MOS transistor MP4 to the MOS transistor MP1 is turned off through the MOS transistor MP3, thereby realizing the current size adjustment of the first temperature coefficient current and obtaining a current with a positive temperature coefficient.

Since the reverse input voltage of the operational amplifier is the feedback voltage, the feedback voltage is equal to the control voltage VBG, and both are zero temperature coefficient voltages. The feedback voltage passes through a grounded resistor R1, and the resistor R1 has a negative temperature coefficient, so the resistance The current branch where R1 is located has a positive temperature coefficient current. The current Imp2=Imp1-Imp4, Imp1=Ir1 through the MOS tube MP2, therefore, adjusting the current through the MOS tube MP4 and the MOS tube MP3 can directly change the size of the current Imp2 through the MOS tube MP2, the MOS tube MP4 and the MOS tube The current size of MP3 is controlled by the control word. Therefore, the current size of the first temperature coefficient current can be adjusted by adjusting the current size of the MOS transistor MP4 and the MOS transistor MP3 through the control word TA<n:1>.

A current temperature coefficient adjustment method, the method applies the above temperature coefficient adjustment module, characterized in that, the step of using the temperature coefficient adjustment module to adjust the temperature coefficient of the current comprises: B1, controlling through a second switch control unit, turning on the first current branch;

B2. Copy the first positive temperature coefficient current in proportion to K1 and K2 through the first current mirror;

B3. Control the switch in the third switch control unit through the control word TC1<m:1> and the control voltages VBN1 and VBN2, so as to realize the compensation of the current size after the temperature coefficient adjustment;

B4. Copy the compensated current through the fourth current mirror, and output the second temperature coefficient current at the current output terminal.

It is further characterized in that,

The size ratio of the MOS tube MP5 and the MOS tube MP2 is K1, and the ratio of the current passing through the MOS tube MP5 to the current of the MOS tube MP2 is K1, that is, Imp5=K1*Imp2;

The size ratio of the MOS tube MP7 and the MOS tube MP2 is K1, and the ratio of the current passing through the MOS tube MP7 to the current of the MOS tube MP2 is K2, that is, Imp7=K2*Imp2;

In step B2, the current flowing through the MOS transistor MP2 is copied according to the proportions K1 and K2 through the MOS transistors MP5 and MP7 in the first current mirror, respectively;

In step B2, the current flowing through the MOS transistor MP2 in the first current mirror is the primary regulated current converted by the voltage-to-current module, and the temperature coefficient of the primary regulated current is TC1, then the temperature coefficient of the current flowing through the MOS transistor MP2 is It is TC1*T, where T represents the temperature, which realizes the one-time adjustment of the temperature coefficient of the one-time adjustment current;

In step B2, the current flowing through the MOS transistor MN1 in the first current branch is Imn1=Imp5+mtc*Imp6～7=K1*Imp2+mtc*K2*Imp2,

Imp5 represents the current flowing through the MOS transistor MP5, Imp6-7 represent the current flowing through the MOS transistor MP6 and the MOS transistor MP7, Imp2 represents the current flowing through the MOS transistor MP2, and mtc represents the MOS transistor MP7 connected to the MOS transistor MN1. Or the number of transistors of the MOS tube MP6, that is, under the control of the control word TC1<n:1>, the number of the MOS tube MP6 of the corresponding bit is closed and turned on), m≥mtc≥0, flowing through the MOS tubes MN5 and MN6 The current temperature coefficient is K1+mtc*K2;

In step B3, the MOS transistors MN5 and MN6 are controlled by the control voltages VBN1 and VBN2 of their gates, and the control voltages VBN1 and VBN2 are zero temperature coefficient voltages;

In step B3, the corresponding MOS transistor MP24 is controlled by the control word TC1<m:1>, so as to realize the adjustment of the magnitude of the current flowing through the MOS transistors MN5 and MN6 to meet the current compensation requirement.

The above structure of the present invention can achieve the following beneficial effects: the current generation circuit with adjustable temperature coefficient includes a voltage-to-current module and a temperature-coefficient adjustment module, and the voltage-to-current module converts the voltage of the bandgap reference voltage source into a voltage with a certain The first temperature coefficient current of the temperature coefficient, and the current size of the first temperature coefficient current is adjusted once, and the temperature coefficient adjustment module adjusts the temperature coefficient of the first adjustment current again, thereby expanding the current temperature coefficient adjustment range to meet the wide Application requirements for bias current temperature coefficient. The temperature coefficient adjustment module has the function of current size compensation, which can compensate the current size after the temperature coefficient adjustment, avoiding the problem of reducing the accuracy of the current size due to the change of the current temperature coefficient, and improving the current generated by the current generation circuit. size accuracy.

Description of drawings

Fig. 1 is the circuit structure block diagram of the present invention;

Fig. 2 is the circuit schematic diagram of the present invention;

3 is a schematic diagram of an array structure in which N MOS transistors MP3 and N MOS transistors MP4 are connected according to the present invention;

FIG. 4 is a simulation diagram of the current temperature coefficient obtained by adjusting the current temperature coefficient adjustment module of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It should be noted that the The terms "comprising" and "having" and any variations thereof in the description and claims and the above-mentioned drawings are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product comprising a series of steps or units Or apparatus is not necessarily limited to those steps or units expressly listed, but may include other steps or units not expressly listed or inherent to the process, method, product or apparatus.

In view of the problems in the prior art that the adjustable range of the bias current temperature coefficient adjustment circuit is small, and the problem that the accuracy of the current size is reduced due to the change of the current temperature coefficient, the present invention provides a temperature coefficient adjustable current generator. Specific examples of circuits.

Referring to Figure 1, a current generation circuit with adjustable temperature coefficient includes a voltage-to-current module 1 and a temperature-coefficient adjustment module 2. One end of the voltage-to-current module 1 is connected to a bandgap reference voltage source, and the other end of the voltage-to-current module 1 is connected to One end of the temperature coefficient adjustment module, the other end of the temperature coefficient adjustment module 2 is the current output terminal; the voltage to current module 1 is used to convert the voltage of the bandgap reference voltage source into the first temperature coefficient current, and the magnitude of the first temperature coefficient current is determined. Perform one adjustment to obtain the primary adjustment current; the temperature coefficient adjustment module 2 is used to adjust the temperature coefficient of the primary adjustment current and compensate the size of the primary adjustment current; the current output terminal IPTAT at the other end of the temperature coefficient adjustment module 2 outputs the temperature The coefficient-adjusted and current magnitude-compensated second temperature coefficient current.

Referring to Fig. 2, the voltage-to-current module 1 includes an operational amplifier 11, a first switch control unit 12, and a current temperature coefficient adjustment unit 13. The forward input end of the operational amplifier 11 is connected to a bandgap reference voltage source, and the voltage of the bandgap reference voltage source is A zero temperature coefficient voltage, the inverting input terminal of the operational amplifier 11 is respectively connected to one end of the first switch control unit 12 and one end of the current temperature coefficient adjustment unit 13, and the other end of the first switch control unit 12 and the other end of the current temperature coefficient adjustment unit 13 are both connected. One end of the temperature coefficient adjustment module 2 is connected, the operational amplifier 11 and the current temperature coefficient adjustment unit 13 are used to generate the first temperature coefficient current related to the temperature coefficient, and the first switch control unit 12 is used to control the current size of the first temperature coefficient current. For one adjustment, the first switch control unit 12 includes a plurality of switches, and the switches are respectively controlled by the control voltage VBP and the control word TA<n:1>.

The specific circuit structure of the voltage-to-current module 2 is as follows: the first switch control unit 12 includes N MOS transistors MP3 and N MOS transistors MP4, wherein N is a positive integer, and the N MOS transistors MP3 and N MOS transistors MP4 are connected to each other. The circuit structure is shown in Figure 3. The current temperature coefficient adjustment unit includes a MOS transistor MP1 and a resistor R1. The output end of the operational amplifier is respectively connected to one end of the resistor R1 and the drain of the MOS transistor MP1. The source of the MOS transistor MP1 is connected to the drain and gate of the MOS transistor MP2. And one end of the temperature coefficient adjustment module, the source of the MOS transistor MP2 is connected to the source of the N MOS transistors MP4 and the temperature coefficient adjustment module, respectively. The gates of the MOS transistors MP4 are controlled by the control voltage VBP, and the drains of the N MOS transistors MP4 The sources of the MOS transistors MP3 are connected one-to-one, the gate of the MOS transistor MP3 is controlled by the control word TA<n:1>, and the drains of the MOS transistors MP3 are connected to the gates of the MOS transistors MP2 and MP5; in this embodiment, the MOS transistor MP1 ~MP4 are all PMOS tubes.

The step of converting the zero temperature coefficient voltage of the bandgap reference voltage source into current by applying the above voltage-to-current module includes: A1, the zero temperature coefficient voltage generated by the bandgap reference voltage source is amplified by the operational amplifier 11 to obtain the amplified current; The voltage source is generated by a bandgap reference circuit.

A2. The amplified current is converted by the current temperature coefficient adjustment unit 13 to obtain the first temperature coefficient current;

A3. The switches in the first switch control unit 12 are controlled by the control voltage VBP and the control word TA<n:1> to realize the primary adjustment of the current size of the first temperature coefficient current and obtain the primary adjustment current.

The specific way for the zero temperature coefficient voltage to generate a current with a certain temperature coefficient through the above steps A1, A2 and A3 is: the zero temperature coefficient voltage generated by the bandgap reference source passes through the MOS tube MP1 and the operational amplifier OPA in the current temperature coefficient adjustment unit. and the resistor R1, which generates a first temperature coefficient current related to the temperature coefficient of the resistor R1. The resistor R1 is a positive temperature coefficient resistor, so the generated first temperature coefficient current has a positive temperature coefficient.

The N MOS transistors MP4 (represented by MP4<n:1> in FIG. 2 ) in the first switch control unit 12 are controlled by the control power supply VBP, and play the role of adjusting the magnitude of the first temperature coefficient current. Since Imp2 +Imp4 or Imp3=Imp1+Ir1, where Imp2 represents the current of the MOS transistor MP2, Imp4 represents the current of the MOS transistor MP4, Imp3 represents the current of the MOS transistor MP3, Imp1 represents the current of the MOS transistor MP1, Ir1 represents the current of the resistor R1, Therefore, by adjusting the control word TA<n:1>, the N MOS transistors MP3 (represented by MP3<n:1> in Figure 2) and the current of the branch where MP4 are located can be adjusted to be turned on or off, so as to realize the voltage One-time adjustment of the output current of the current transfer module, that is, when a certain bit in the control word is n=0 and TA<n:1>=0, the MOS tube MP3 of the corresponding bit is closed, and the current of the MOS tube MP4 of the corresponding bit is closed. The MOS transistor MP3 is connected to the branch where the MOS transistor MP1 is located, which plays the role of adding the current of the MOS transistor MP2. When a certain bit in the control word TA=1, TA<n:1>=1, the MOS transistor MP3 Turn off, the current on the branch from MOS tube MP4 to MOS tube MP1 is turned off through MOS tube MP3, so the voltage-to-current module can adjust the output positive temperature coefficient current of the voltage-to-current module, and the positive temperature coefficient current is determined by the resistor R1, The magnitude of the current is determined by the size ratio of the MOS transistor MP5 and the MOS transistor MP2.

The temperature coefficient adjustment module 2 includes a first current mirror 21 to a fourth current mirror 24, a second switch control unit 25, and a third switch control unit 26. The first current mirror 21 is used to convert the power supply to the first temperature coefficient output by the current module The current is replicated in proportions K1 and K2, the second current mirror 22 and the third current mirror 23 are used to replicate the current passing through the first current mirror 21 in proportion to K5, the first current mirror 21, the second switch control unit, the One end of the two current mirrors are connected in sequence to form a first current branch, one end of the third current mirror, one end of the third switch control unit, and one end of the fourth current mirror are connected in sequence to form a second current branch, and the other end of the second current mirror is connected to the third current branch. The other end of the current mirror is connected, and the second switch control unit controls the turn-on or turn-off of the first current branch, the third switch control unit controls the turn-on or turn-off of the second current branch, and the fourth current mirror The other end is the current output terminal, which is used to output the second temperature coefficient current after the temperature coefficient adjustment and the current magnitude compensation. Several switches in the second switch control unit are controlled by the control word TC1<n:1>, and the third switch Several switches in the unit are respectively controlled by the control word TC1<n:1>, the control voltages VBN1 and VBN2, and the temperature coefficient of the current can be adjusted once through the control of the switches in the second switch control unit by the control word TC1<n:1>. Adjustment, through the control of the switch in the third switch unit by the control word TC1<n:1>, the control voltages VBN1 and VBN2, the current size compensation of the primary adjustment current is realized.

The specific circuit structure of the temperature coefficient adjustment module is as follows: the first current mirror includes MOS transistors MP2, MOS transistors MP5 and MP7, the second current mirror branch includes MOS transistors MN1-MN4, and the third current mirror branch includes MOS transistors MP8-MP11 , the fourth current mirror branch includes MOS transistors MN7-MN10, the second switch control unit includes N MOS transistors MP6, and the third switch control unit includes M MOS transistors MP24, M MOS transistors MN5, and M MOS transistors MN6. Among them, M is a positive integer, the source of MOS tube MP5 is connected to the source of MOS tube MP2, MP4, MP7, MP9, MP11 respectively, the drain of MOS tube MP5 is respectively connected to the drain and gate of MOS tube MN1 and the gate of MOS tube MN3, The source of MOS transistor MN1 is respectively connected to the gate of MOS transistor MN2, the source and the gate of MOS transistor MN4, the drain of MOS transistor MP9 is respectively connected to the gate of MOS transistor MP9, the gate of MOS transistor MP11, the drain of MOS transistor MP8, and the drain of MOS transistor MP8 The gate is connected to the source of MOS tube MP8, the gate of MOS tube MP10, the source of MOS tube MN3, the drain of MOS tube MN3 is connected to the drain of MOS tube MN4, and the source of MOS tube MN2 is respectively connected to the source of MOS tube MN4 and the source of MOS tube MN6. , MN8, MN10 source, MOS tube MP11 drain is connected to MOS tube MP10 drain, MOS tube MP10 source is connected to M MOS tube MP24 source, MOS tube MN7 source, gate and MOS tube MN9 gate, MOS tube The drains of MP24 are connected in series with the MOS transistors MN5 and MN6, the gates of the M MOS transistors MP6 are controlled by the control word TC1<n:1>, the gates of the MOS transistors MP24 are controlled by the control word TC1<n:1>, and the M MOS transistors MN5 Controlled by the control voltage VBN1, M MOS transistors MN6 are controlled by the control power supply VBN2, the drain of the MOS transistor MN7 is respectively connected to the drain and gate of the MOS transistor MN8 and the gate of the MOS transistor MN10, and the drain of the MOS transistor MN10 is connected to the drain of the MOS transistor MN9. , the source of MOS tube MN9 is the current output terminal IPTAT.

In this embodiment, the MOS transistors MP5 to MP11 and the MOS transistor MP24 are all PMOS transistors, and the MOS transistors MN1 to MN10 are all NMOS transistors. The size ratio of the MOS tube MP5 and the MOS tube MP2 is K1, and the ratio of the current through the MOS tube MP5 to the current of the MOS tube MP2 is K1, that is, Imp5=K1*Imp2; the size ratio of the MOS tube MP7 and the MOS tube MP2 is K1, The ratio of the current passing through the MOS transistor MP7 to the current of the MOS transistor MP2 is K2, that is, Imp7=K2*Imp2, wherein the current Imp7 of the MOS transistor MP7 and the current of the MOS transistor MP2 are Imp2.

The step of applying the above-mentioned temperature coefficient adjustment module to adjust the temperature coefficient of the primary adjustment current includes: B1, controlling the second switch control unit to make the first current branch conduct;

B2. Copy the first positive temperature coefficient current in proportion to K1 and K2 through the first current mirror;

B3. Control the switch in the third switch control unit through the control word TC1<m:1> and the control voltages VBN1 and VBN2, so as to realize the compensation of the current size after the temperature coefficient adjustment;

B4. Copy the compensated current through the fourth current mirror, and output the second temperature coefficient current at the current output terminal.

The specific method of generating a current with a certain temperature coefficient through the above steps B1 to B4: the current flowing through the MOS transistor MP2 is copied in proportion to K1 and K2 through the MOS transistors MP5 and MP7 in the first current mirror; The current of the MOS transistor MP2 in the mirror is the primary regulated current converted by the voltage-to-current module, and the temperature coefficient of the primary regulated current is TC1, that is, Imp2=TC1*T, where T represents the temperature. Therefore, the current flowing through the branch where the MOS transistor MN1 is located is:

Imn1=Imp5+mtc*Imp6～7=K1*Imp2+mtc*K2*Imp2,

Imp5 represents the current flowing through the MOS transistor MP5, Imp6-7 represent the current flowing through the MOS transistor MP6 and the MOS transistor MP7, Imp2 represents the current flowing through the MOS transistor MP2, and mtc represents the MOS transistor MP7 connected to the MOS transistor MN1. Or the number of transistors of the MOS tube MP6, that is, under the control of the control word TC1<n:1>, the number of the MOS tube MP6 of the corresponding bit is closed and turned on), m≥mtc≥0; therefore, the flow through the MOS tube MN5 , The current temperature coefficient of MN6 is K1+mtc*K2;

In step B3, the MOS transistors MN5 and MN6 are controlled by the control voltages VBN1 and VBN2 on their gates, and the control voltages VBN1 and VBN2 are zero temperature coefficient voltages. The corresponding MOS transistor MP24 is controlled by the control word TC1<m:1>, so as to realize the adjustment of the current flowing through the MOS transistors MN5 and MN6 to meet the current compensation requirements. That is, when a certain bit m=0 and TC1=0, the MOS tube MP6 of the corresponding bit is closed, and the current of the corresponding MOS tube MP7 is connected to the branch current of the MOS tube MN1 through the MOS tube MP6, which acts as the current of the MOS tube MP5. Additive action, when a certain bit m=1, TC1=1, the MOS tube MP6 of the corresponding bit is closed, and the corresponding MOS tube MP7 current is turned off through the MOS tube MP6, so that the TC1 of the mtc bit is set to 0, then you can A current corresponding to the temperature coefficient of K1+mtc*K2 is obtained, thereby realizing the adjustment of the current temperature coefficient and expanding the adjustment range of the current temperature coefficient.

However, it can also be obtained from the above formula that the magnitude of the current flowing through the MOS transistors MN5 and MN6 also changes accordingly. Therefore, the second current mirror and the third current mirror of equal size and proportion pass through the MOS transistors MN1 to MN4 and the MOS transistors MP8 to MP11. The proportions replicate the currents Imn1-2 passing through the MOS transistors MN1 and MN2. For circuit analysis we get:

mtc*Imp24 or Imn5～6+Imn7～8=Imn10～11=Imp8～9=Imn3～4=Imn1～2;

Among them, Imp24 represents the current flowing through the MOS transistor MP24, Imn5-6 represents the current flowing through the MOS transistors MN5 and MN6, Imn7-8 represents the current flowing through the MOS transistor MN7 and MN8, and Imn10-11 represents the current flowing through the MOS transistors MN10 and MN8. For the current of MN11, Imp8-9 represent the current flowing through the MOS transistors MP8 and MP9, Imn3-4 represent the current flowing through the MOS transistor MN3 and MN4, and Imn1-2 represent the current flowing through the MOS transistor MN1 and MN2. Since the control word that controls the MOS transistor MP24 is equal to the control word that controls the temperature coefficient adjustment of the MOS transistor MP6, so:

Imn7～8=Imn1～2-mtc*Imp24 or Imn5～6=Imp5+mtc*Imp6～7-mtc*Imp24 or Imn5～6;

The current flowing through the MOS transistors MN5 and MN6 is controlled by their gate voltages VBN1 and VBN2, which is a zero temperature coefficient voltage, so the temperature coefficient of the current flowing through the MOS transistor MP24 or the MOS transistor MN5 and MN6 remains unchanged, but the magnitude The current Imp5 is still the basis, but the temperature coefficient is still K1+mtc*K2, so that while the current temperature coefficient adjustment is realized, the current size compensation is realized, and the current caused by the temperature change or current temperature coefficient change in the circuit is avoided. The problem of size reduction occurs. Therefore, the temperature coefficient adjustment module can output a positive temperature coefficient current with a temperature coefficient of K1+mtc*K2. In the case of normal temperature operation, no matter how the current temperature coefficient is adjusted, the current size of the output second temperature coefficient current is the flow rate. The magnitudes of the currents passing through the MOS transistors MN7-MN8 are all the set Imp5 value. Therefore, the setting of the third switch in the current temperature coefficient compensation module improves the accuracy of the output current of the current generation circuit, so as to provide current for other subsequent circuit modules. A stable second temperature coefficient current.

To sum up, the current generation circuit of the present application compensates the current temperature coefficient in advance through the voltage-to-current module for the PVT change in the circuit, that is, generates a first temperature coefficient current, and the first temperature coefficient current is a positive temperature coefficient current, and The current size of the first temperature coefficient current is adjusted once, and then the current temperature coefficient of the primary adjustment current is compensated twice through the current temperature coefficient adjustment module to obtain a larger current temperature coefficient to meet the requirements of higher temperature circuits, and The current size after the current temperature coefficient adjustment is adjusted (compensated) twice to provide a larger current to avoid the current size deviation caused by the circuit gain or linearity within the operating temperature range.

Figure 4 shows the current temperature coefficient adjustment function simulated by the current generation circuit. In Figure 4, the horizontal axis represents the temperature of the circuit, the vertical axis represents the current size, and the control mta is consistent, the change of the temperature coefficient of the output current under the same current can be obtained, that is, the circuit operating temperature range temp is in the range of -40℃～125℃, Each time mtc is adjusted, the current temperature coefficient can be changed from 337nA/°C to 640nA/°C, and at the mark V2, that is, under the normal operating temperature of the chip, it can be clearly seen that each current line maintains the same current size there, because The vertical axis is the current, and the horizontal axis is the temperature. Therefore, every time mtc is adjusted, the output current will not be affected, the current will remain unchanged, and the current temperature coefficient will change. of stability.

The above are only preferred embodiments of the present application, and the present invention is not limited to the above embodiments. It can be understood that other improvements and changes directly derived or thought of by those skilled in the art without departing from the spirit and concept of the invention should be considered to be included in the protection scope of the invention.

Claims (10)

1. A current generation circuit with an adjustable temperature coefficient, comprising a voltage-to-current module and a temperature-coefficient adjustment module, one end of the voltage-to-current module is connected to a bandgap reference voltage source, and the other end of the voltage-to-current module is connected to the One end of the temperature coefficient adjustment module, and the other end of the temperature coefficient adjustment module is the current output end; The voltage-to-current module is configured to convert the voltage of the bandgap reference voltage source into a first temperature coefficient current, and adjust the magnitude of the first temperature coefficient current once to obtain a primary adjustment current; The temperature coefficient adjustment module is used to adjust the temperature coefficient of the primary adjustment current, and to compensate the size of the primary adjustment current; The other end of the temperature coefficient adjustment module outputs the second temperature coefficient current after the temperature coefficient adjustment and current magnitude compensation. 2 . The current generation circuit with adjustable temperature coefficient according to claim 1 , wherein the voltage-to-current module comprises an operational amplifier, a first switch control unit, and a current temperature coefficient adjustment unit, and a positive voltage of the operational amplifier. The bandgap reference voltage source is connected to the input end, the voltage of the bandgap reference voltage source is zero temperature coefficient voltage, and the reverse input end of the operational amplifier is respectively connected to one end of the first switch control unit, the current temperature coefficient One end of the adjustment unit, the other end of the first switch control unit, and the other end of the current temperature coefficient adjustment unit are all connected to one end of the temperature coefficient adjustment module, and the operational amplifier and the current temperature coefficient adjustment unit are used to generate the first temperature coefficient related A temperature coefficient current, the first switch control unit is used to adjust the current size of the first temperature coefficient current once, the first switch control unit includes a plurality of switches, the switches are respectively controlled by the control voltage VBP, Word TA<n:1> controls. 3. The current generating circuit with adjustable temperature coefficient according to claim 2, wherein the first switch control unit comprises N MOS transistors MP3 and N MOS transistors MP4, wherein N is a positive integer, so The current temperature coefficient adjustment unit includes a MOS transistor MP1 and a resistor R1. The output end of the operational amplifier is respectively connected to one end of the resistor R1 and the gate of the MOS transistor MP1. The drain of the MOS transistor MP1 is connected to the temperature coefficient adjustment module. The drain and gate of the MOS transistor MP2, the source of the MOS transistor MP2 are respectively connected to the source of the N MOS transistors MP3, the gate of the MOS transistor MP5 in the temperature coefficient adjustment module, and the gates of the N MOS transistors MP4. The poles are all controlled by the control voltage VBP, the drains of the N MOS transistors MP4 are connected to the drains of the N MOS transistors MP3 in one-to-one correspondence, and the gates of the MOS transistors MP3 are controlled by the control word TA<n:1> The source of the MOS transistor MP4 is connected to the source of the MOS transistor MP5 and the MOS transistors MP7, MP9 and MP11 in the temperature coefficient adjustment module. 4. The current generating circuit with adjustable temperature coefficient according to claim 3, wherein the step of applying the voltage-to-current module to convert the zero temperature coefficient voltage of the bandgap reference voltage source into current comprises: A1, zero The temperature coefficient voltage is amplified by the operational amplifier to obtain the amplified current; A2. The amplified current is converted by the current temperature coefficient adjustment unit to obtain the first temperature coefficient current; A3. Control the switches in the first switch control unit through the control voltage VBP and the control word TA<n:1>, so as to realize the primary adjustment of the current size of the first temperature coefficient current, and obtain the primary adjustment current. 5 . The current generating circuit with adjustable temperature coefficient according to claim 4 , wherein in step A2 , the amplified current is compensated by the MOS transistor MP1 and the resistor R1 in the current temperature coefficient adjusting unit to generate a temperature coefficient equal to that of the resistor R1 . the associated first temperature coefficient current. 6 . The current generating circuit with adjustable temperature coefficient according to claim 5 , wherein, in step A3 , the control voltage VBP and the control word TA<n:1> are used to control the N switches in the first switch control unit respectively. 7 . The MOS transistor MP4 and the N MOS transistors MP3 are controlled, and the specific steps of adjusting the first temperature coefficient current through the first switch control unit include: when the first temperature coefficient current flows through the MOS transistor MP4, the control voltage VBP is used to control the current. The gates of the N MOS transistors MP4 are controlled, and at the same time, the gates of the N MOS transistors MP3 are controlled by the control word TA<n:1>, and the current size of the first temperature coefficient current is adjusted once. The specific steps include: A321, When n=0, TA<n:1>=0, the MOS tube MP3 of the corresponding bit is closed, and the current of the MOS tube MP4 of the corresponding bit enters the branch of the MOS tube MP1 through the MOS tube MP3, so that the current of the MOS tube MP1 and the current of the MOS tube MP1 are realized. The addition of the current of the MOS tube MP2; A322, when n=1, TA<n:1>=1, the MOS tube MP3 is turned off, the current from the MOS tube MP4 to the MOS tube MP1 branch is turned off through the MOS tube MP3, and the output Positive temperature coefficient current. 7 . The current generation circuit with adjustable temperature coefficient according to claim 1 , wherein the temperature coefficient adjustment module comprises a first current mirror to a fourth current mirror, a second switch control unit, and a third switch. 8 . A control unit, the first current mirror is used to copy the first temperature coefficient current output by the power-to-current module in proportion to K1 and K2, and the second current mirror and the third current mirror are used to The current of the first current mirror is replicated in proportion to K5. One end of the first current mirror, the second switch control unit, and the second current mirror are connected in sequence to form a first current branch, and one end of the third current mirror and the third switch control One end of the unit and the fourth current mirror are connected in sequence to form a second current branch, the other end of the second current mirror is connected to the other end of the third current mirror, and the first current is controlled by the second switch control unit. The turn-on or turn-off of the branch is controlled, and the turn-on or turn-off of the second current branch is controlled by the third switch control unit, and the other end of the fourth current mirror is the current output terminal, which is used After outputting the second temperature coefficient current after the temperature coefficient adjustment and current magnitude compensation, several switches in the second switch control unit are controlled by the control word TC1<n:1>, and the third switch unit in the A number of switches are controlled by the control word TC1<n:1>, the control voltages VBN1, VBN2, respectively, and the temperature coefficient adjustment of the primary current is realized through the control of the switch in the second switch control unit by the control word TC1<n:1>. Through the control of the switches in the third switch unit by the control word TC1<n:1>, the control voltages VBN1 and VBN2, the current size compensation of the primary adjustment current is realized. 8 . The current generating circuit with adjustable temperature coefficient according to claim 7 , wherein the first current mirror comprises MOS transistors MP2 , MOS transistors MP5 and MP7 , and the second current mirror branch comprises MOS transistors 8 . MN1 to MN4, the third current mirror branch includes MOS transistors MP8 to MP11, the fourth current mirror branch includes MOS transistors MN7 to MN10, the second switch control unit includes m MOS transistors MP6, and the The third switch control unit includes M MOS transistors MP24, M MOS transistors MN5, and M MOS transistors MN6, wherein M is a positive integer, and the drain of the MOS transistor MP5 is connected to the drain and gate of the MOS transistor MN1, respectively. and the gate of the MOS transistor MN3, the source of the MOS transistor MN1 is respectively connected to the gate of the MOS transistor MN2, the source and the gate of the MOS transistor MN4, the drain of the MOS transistor MP9 is respectively connected to the gate of the MOS transistor MP9, The gate of the MOS transistor MP11 and the drain of the MOS transistor MP8, the gate of the MOS transistor MP8 is respectively connected to the source of the MOS transistor MP8, the gate of the MOS transistor MP10, and the source of the MOS transistor MN3, and the drain of the MOS transistor MN3 is connected to the MOS transistor The drain of the MOS transistor MN4, the source of the MOS transistor MN2 is respectively connected to the source of the MOS transistor MN4, the source of the MOS transistors MN6, MN8 and MN10, the drain of the MOS transistor MP11 is connected to the drain of the MOS transistor MP10, and the The source of the MOS transistor MP10 is connected to the source of the M MOS transistors MP24, the source and gate of the MOS transistor MN7, and the gate of the MOS transistor MN9. The drain of the MOS transistor MP24 is connected in series with the MOS transistors MN5 and MN6 in sequence. The gate of the MOS transistor MP6 is controlled by the control word TC1<n:1>, the gate of the MOS transistor MP24 is controlled by the control word TC1<n:1>, the M MOS transistors MN5 are controlled by the control voltage VBN1, and the M MOS transistors MN5 are controlled by the control voltage VBN1. The MOS transistor MN6 is controlled by the control power supply VBN2, the drain of the MOS transistor MN7 is respectively connected to the drain and gate of the MOS transistor MN8 and the gate of the MOS transistor MN10, the drain of the MOS transistor MN10 is connected to the drain of the MOS transistor MN9, The source of the MOS transistor MN9 is the current output terminal. 9 . The current generating circuit with adjustable temperature coefficient according to claim 8 , wherein the step of adjusting the temperature coefficient of the current by using the temperature coefficient adjusting module comprises: B1 , controlling by a second switch control unit, turning on the first current branch; B2. Copy the first positive temperature coefficient current in proportion to K1 and K2 through the first current mirror; B3. Control the switch in the third switch control unit through the control word TC1<m:1> and the control voltages VBN1 and VBN2, so as to realize the compensation of the current size after the temperature coefficient adjustment; B4. Copy the compensated current through the fourth current mirror, and output the second temperature coefficient current at the current output terminal. 10. The current generating circuit with adjustable temperature coefficient according to claim 8, wherein the size ratio of the MOS transistor MP5 and the MOS transistor MP2 is K1, and the current passing through the MOS transistor MP5 and the MOS transistor MP2 have a size ratio of K1. The ratio of the current is K1, that is, Imp5=K1*Imp2; the size ratio of the MOS tube MP7 and the MOS tube MP2 is K1, and the ratio of the current passing through the MOS tube MP7 to the current of the MOS tube MP2 is K2, that is, Imp7=K2* Imp2; in step B2, the current flowing through the MOS transistor MP2 is copied according to the proportions K1 and K2 through the MOS transistors MP5 and MP7 in the first current mirror, respectively.

Images