Current generating circuit and current detecting circuit

Abstract

The present disclosure provides a current generation circuit and a current detection circuit, which can provide first and second reference currents with different temperature characteristics by using a reference unit in the current generation circuit, and adaptively adjust the steady-state operating point of the circuit itself under the control of first and second bias voltages according to the first and second reference currents, and access an input current and the first bias voltage through an input branch in a mirror output unit thereof, and access the second bias voltage through an output branch and provide an output current, wherein the conversion ratio of the output current to the input current provided by the mirror output unit is mirror-set as the ratio of the first reference current to the second reference current. Thus, the current proportional relationship is constructed by using the current mirror circuit structure including bipolar junction transistors, so as to realize the conversion of the temperature characteristics of the current to the current, so as to be suitable for the circuit application in which the current conversion voltage cannot be realized in practical application.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of integrated circuit technology, and in particular, to a current generation circuit and a current detection circuit. BACKGROUND

[0002] In the design of integrated circuits, it is often necessary to use temperature-independent reference voltages and / or temperature-independent reference currents, which are usually generated by using a band-gap reference circuit.

[0003] For example, in order to generate a temperature-independent (i.e. zero temperature coefficient) reference voltage, the negative temperature coefficient characteristic of a bipolar transistor is often used to generate a negative temperature coefficient voltage, and the conversion characteristic of a resistor is used to convert a positive temperature coefficient current into a positive temperature coefficient voltage, and then the negative temperature coefficient voltage and the positive temperature coefficient voltage are weighted to obtain a zero temperature coefficient reference voltage. Or in order to generate a temperature-independent reference current, the negative temperature coefficient characteristic of a bipolar transistor and the conversion characteristic of a resistor are first used to generate a negative temperature coefficient current, and then the negative temperature coefficient current and a positive temperature coefficient current are weighted to obtain a zero temperature coefficient current.

[0004] In practical applications, it is also common to use both temperature-independent reference voltages and temperature-independent reference currents. In this case, for example, a band-gap reference circuit can be designed to generate a temperature-independent reference voltage, and another band-gap reference circuit can be designed to generate a temperature-independent reference current. Or a band-gap reference circuit can be used to generate a zero temperature coefficient reference current (or reference voltage), and additional circuits can be added to mirror the zero temperature coefficient reference current (or reference voltage) and convert it into a zero temperature coefficient reference voltage (or reference current). The additional circuit usually has a bias current source for mirroring the current (or mirroring the voltage) and at least one resistor for converting the current to voltage (or converting the voltage to current).

[0005] In existing MOS processes, due to different current generation methods, the common temperature characteristics of reference currents are zero temperature characteristic, positive temperature characteristic and negative temperature characteristic. In some current generation circuits, such as current detection circuits, it is necessary to convert the temperature characteristics of the current, such as converting a positive temperature characteristic current into a zero temperature characteristic current. The solution in the prior art is to convert the current into a voltage, and then pass through a resistor with a specific temperature coefficient to obtain a current with a corresponding temperature coefficient, but not all currents are suitable for conversion into a voltage, which greatly limits its application range. SUMMARY

[0006] To solve the above technical problems, the present disclosure provides a current generating circuit and a current detecting circuit.

[0007] In one aspect, the present disclosure provides a current generating circuit, comprising:

[0008] a reference unit for providing first and second reference currents with different temperature characteristics, and for adaptively adjusting a steady state operating point of itself under the control of first and second bias voltages according to the first and second reference currents; and

[0009] a mirror output unit comprising an input branch and an output branch, the input branch being connected to an input current and the first bias voltage, and the output branch being connected to the second bias voltage and providing an output current,

[0010] wherein the input current has the same temperature characteristic as the first reference current, and the output current has the same temperature characteristic as the second reference current, and the conversion ratio of the output current to the input current provided by the mirror output unit is mirror set to the ratio of the first reference current to the second reference current.

[0011] Preferably, the aforementioned reference unit comprises:

[0012] a first current source, a first transistor and a second current source, a first end of the first current source being connected to a power supply end and connected to a power supply voltage, a second end of the first current source being connected to the first transistor and the second current source in series to ground, the first current source being configured to provide a first reference current with a first temperature characteristic, a control end of the first transistor being connected to the aforementioned first bias voltage;

[0013] a first operational amplifier, a positive input end of the first operational amplifier being connected to a connection node of the aforementioned first current source and the first transistor, a negative input end of the first operational amplifier being connected to a first reference voltage, and an output end of the first operational amplifier being connected to the control end of the first transistor.

[0014] Preferably, the aforementioned reference unit further comprises:

[0015] a third current source and a second transistor, a first end of the third current source being connected to a power supply end and connected to a power supply voltage, a second end of the third current source being connected to the second transistor and the second current source in series, the third current source being configured to provide a second reference current with a second temperature characteristic, a control end of the second transistor being connected to the aforementioned second bias voltage;

[0016] a second operational amplifier, a positive input end of the second operational amplifier being connected to a connection node of the aforementioned third current source and the second transistor, a negative input end of the second operational amplifier being connected to a second reference voltage, and an output end of the second operational amplifier being connected to the aforementioned second current source.

[0017] Preferably, the input branch of the aforementioned mirror output unit comprises:

[0018] a fourth current source, a third transistor and a fifth current source, a first end of the fourth current source is connected to a power supply terminal for inputting a power supply voltage, a second end of the fourth current source is connected to a ground terminal in series with the third transistor and the fifth current source, the fourth current source is configured to provide an input current with a first temperature characteristic, a control terminal of the third transistor is connected to the first bias voltage;

[0019] a third operational amplifier, a positive input terminal of the third operational amplifier is connected to a connection node of the fourth current source and the third transistor, a negative input terminal of the third operational amplifier is connected to a third reference voltage, and an output terminal of the third operational amplifier is connected to the fifth current source.

[0020] Preferably, the output branch of the mirror output unit comprises:

[0021] a fourth transistor, a first end of the fourth transistor is configured as an output terminal of the current generating circuit for providing an output current with a second temperature characteristic, a second end of the fourth transistor is connected to the fifth current source in series, and a control terminal of the fourth transistor is connected to the second bias voltage.

[0022] Preferably, the second current source and / or the fifth current source is a variable current source.

[0023] Preferably, any one of the first transistor, the second transistor, the third transistor and the fourth transistor is a bipolar junction transistor.

[0024] Preferably, the first transistor, the second transistor, the third transistor and the fourth transistor are all NPN type bipolar junction transistors.

[0025] Preferably, a conversion ratio of the output current to the input current is:

[0026]

[0027] wherein IC1 represents the first reference current, IC2 represents the second reference current, ICOUT represents the output current, and ICIN represents the input current.

[0028] In another aspect, the present disclosure also provides a current detection circuit, comprising:

[0029] a current generating circuit as described above.

[0030] The current generation circuit and the current detection circuit provided by the present disclosure can provide first reference current and second reference current with different temperature characteristics by using the reference unit in the current generation circuit, and can adaptively adjust the steady-state operating point of the circuit under the control of the first bias voltage and the second bias voltage according to the first reference current and the second reference current, and can access the input current and the first bias voltage through the input branch in the mirror output unit, and can access the second bias voltage through the output branch and provide the output current, wherein the input current has the same temperature characteristic as the first reference current, and the output current has the same temperature characteristic as the second reference current, and the conversion ratio of the output current to the input current provided by the mirror output unit is set to be the ratio of the first reference current to the second reference current. Thus, the current proportional relationship is constructed by using the current mirror circuit structure including the bipolar junction transistor, so as to realize the conversion of the temperature characteristics of the current to the current, and to be suitable for the circuit application in which the current conversion voltage cannot be realized in practical application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings.

[0032] Figure 1 A structure schematic diagram of a current generation circuit provided by an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present disclosure, the present disclosure will be described in detail below with reference to the relevant drawings. The preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure can be realized in different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the present disclosure more thorough and comprehensive.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terminology used in the description of the present disclosure is only for the purpose of describing the specific embodiments of the present disclosure, and is not intended to limit the present disclosure.

[0035] Voltage or current references with little temperature dependence are essential in many analog circuits. It is worth noting that because most process parameters vary with temperature, if a reference is temperature independent, it is usually also process independent. We assume that if two voltages with opposite temperature coefficients are added with appropriate weights, a reference voltage with zero temperature coefficient will eventually be obtained. For example, voltage V+ has a positive temperature coefficient, and voltage V_ has a negative temperature coefficient, and there are appropriate weights α and β that satisfy:

[0036]

[0037] Among various device parameters in semiconductor processes, the characteristic parameters of bipolar transistors are proved to have the best repeatability and can provide strictly defined quantities with positive and negative temperature coefficients. Although many parameters of MOS devices have been considered for generating reference voltages, bipolar circuits still form the core of such circuits. Bipolar transistors (BJT) have the following two characteristics: 1. the difference ΔVBE of the base-emitter voltage of two bipolar transistors with different current densities has a positive temperature characteristic; 2. the base-emitter voltage VBE of a bipolar transistor has a negative temperature characteristic. By adding the two voltages with certain weights, the resulting voltage can be approximately zero temperature coefficient.

[0038] For a bipolar transistor, the collector current (IC) is related to the base-emitter voltage (VBE, which is also the BE junction voltage of the bipolar transistor) as follows:

[0039]

[0040] where VT is the thermal voltage kT / q, and IS is the saturation current.

[0041] In some actual circuit applications, the conversion of temperature characteristics can be realized by converting the current into voltage and then through a resistance with a certain temperature coefficient to obtain a current with a corresponding temperature coefficient. However, not all application scenarios are suitable for the current-to-voltage conversion method. Therefore, the current generation circuit in the embodiments of the present disclosure is proposed to realize the conversion of temperature characteristics from current to current, so as to improve the applicability of the circuit.

[0042] In the following, the present disclosure will be described in detail with reference to the accompanying drawings.

[0043] Figure 1 A structure schematic diagram of a current generation circuit provided by the embodiments of the present disclosure is shown.

[0044] Reference Figure 1 The embodiments of the present disclosure provide a current generation circuit 100, which comprises a reference unit 110 and a mirror output unit 120.

[0045] The reference unit 110 is configured to provide a first reference current IC1 and a second reference current IC2 with different temperature characteristics, and to adaptively adjust the steady-state operating point of its own circuit according to the first reference current IC1 and the second reference current IC2 under the control of a first bias voltage VA and a second bias voltage Vbias.

[0046] The mirror output unit 120 comprises an input branch 121 connected to the input current ICIN and the first bias voltage VA, and an output branch 122 connected to the second bias voltage Vbias and providing the output current ICOUT,

[0047] wherein the input current ICIN has the same temperature characteristic as the first reference current IC1, for example TC1, and the output current ICOUT has the same temperature characteristic as the second reference current IC2, for example TC2, and the conversion ratio of the output current ICOUT provided by the mirror output unit 120 to the input current ICIN is mirrored to the ratio of the first reference current IC1 to the second reference current IC2.

[0048] Further, in the present embodiment, the aforementioned reference unit 110 comprises:

[0049] a first current source I1, a first transistor BJT1 and a second current source I4, the first end of the first current source I1 is connected to a power supply terminal and connected to the power supply voltage VCC, the second end of the first current source I1 is connected to the ground through the first transistor BJT1 and the second current source I4 in series, the first current source I1 is used to provide the first reference current IC1 with the first temperature characteristic TC1, the control terminal of the first transistor BJT1 is connected to the aforementioned first bias voltage VA;

[0050] a first operational amplifier OP1, the positive input terminal of the first operational amplifier OP1 is connected to the connection node of the aforementioned first current source I1 and the first transistor BJT1, the negative input terminal of the first operational amplifier OP1 is connected to the first reference voltage Va, and the output terminal of the first operational amplifier OP1 is connected to the control terminal of the first transistor BJT1.

[0051] Further, in the present embodiment, the aforementioned reference unit 110 further comprises:

[0052] a third current source I2 and a second transistor BJT2, the first end of the third current source I2 is connected to a power supply terminal and connected to the power supply voltage VCC, the second end of the third current source I2 is connected to the second transistor BJT2 and the second current source I4 in series, the third current source I2 is used to provide the second reference current IC2 with the second temperature characteristic TC2, the control terminal of the second transistor BJT2 is connected to the aforementioned second bias voltage Vbias;

[0053] a second operational amplifier OP2, the positive input terminal of the second operational amplifier OP2 is connected to the connection node of the aforementioned third current source I2 and the second transistor BJT2, the negative input terminal of the second operational amplifier OP2 is connected to the second reference voltage Vb, and the output terminal of the second operational amplifier OP2 is connected to the aforementioned second current source I4.

[0054] Further, in the present embodiment, the input branch 121 of the aforementioned mirror output unit 120 comprises:

[0055] The fourth current source I3, the third transistor BJT3, and the fifth current source I5 are connected in series. The first terminal of the fourth current source I3 is connected to the power supply terminal and connected to the power supply voltage VCC. The second terminal is connected to the third transistor BJT3 and the fifth current source I5 to ground in series. The fourth current source I3 is used to provide the input current ICIN of the first temperature characteristic TC1. The control terminal of the third transistor BJT3 is connected to the aforementioned first bias voltage VA.

[0056] The third operational amplifier OP3 has its positive input terminal connected to the connection node of the aforementioned fourth current source I3 and the third transistor BJT3, its negative input terminal connected to the third reference voltage Vc, and its output terminal connected to the aforementioned fifth current source I5.

[0057] Furthermore, in this embodiment, the output branch 122 of the aforementioned mirror output unit 120 includes:

[0058] The fourth transistor BJT4 has its first terminal serving as the output terminal of the current generating circuit 100, used to provide the output current ICOUT of the second temperature characteristic TC2. Its second terminal is connected in series to the fifth current source I5, and its control terminal is connected to the aforementioned second bias voltage Vbias.

[0059] Furthermore, the aforementioned second current source I4 and / or fifth current source I5 are variable current sources. In this embodiment, the second current source I4 is controlled by the output signal of the second operational amplifier OP2, adaptively adjusting the common emitter potential of the first transistor BJT1 and the second transistor BJT2. Thus, when temperature changes cause changes in current values ​​(IC1 and IC2), the steady-state operating points of the first transistor BJT1 and the second transistor BJT2 are adaptively adjusted. This is a common application of operational amplifier circuits, and therefore will not be described in detail here.

[0060] Furthermore, in this embodiment, any one of the aforementioned first transistor BJT1, second transistor BJT2, third transistor BJT3, and fourth transistor BJT4 is a bipolar junction transistor (BJT).

[0061] Furthermore, in this embodiment, the aforementioned first transistor BJT1, second transistor BJT2, third transistor BJT3, and fourth transistor BJT4 are all NPN bipolar junction transistors.

[0062] Combination Figure 1 As described above, in this embodiment, for the first transistor BJT1 and the second transistor BJT2, the BE junction voltage of the first transistor BJT1 is... The BE junction voltage of the second transistor BJT2 Thus

[0063] Similarly, for the third transistor BJT3 and the fourth transistor BJT4, the BE junction voltage of the third transistor BJT3 the BE junction voltage of the fourth transistor BJT4 Thus

[0064] According to Figure 1 As shown in FIG. 1, since the base of the first transistor BJT1 and the third transistor BJT3 are both connected to the first bias voltage VA, and the base of the second transistor BJT2 and the fourth transistor BJT4 are both connected to the second bias voltage Vbias, thus AVBE1 = Vbias - VA = AVBE2. According to the formula (3) and (4), we have:

[0065] Therefore, the conversion ratio of the output current ICOUT and the input current ICIN is:

[0066]

[0067] Wherein, the input current ICIN and the first reference current IC1 have the same temperature characteristic TC1, and have the same temperature coefficient, thus the influence of temperature change on the current value is offset. Since the formula (5) always holds, the output current ICOUT has the same temperature characteristic TC2 as the second reference current IC2, thus obtaining the current with the desired temperature characteristic.

[0068] On the other hand, the present disclosure also provides a current detection circuit, comprising:

[0069] The current generation circuit 100 as described in the foregoing embodiments.

[0070] In summary, the current generation circuit 100 and the current detection circuit having the current generation circuit 100 provided by the embodiments of the present disclosure can utilize the reference unit 110 in the current generation circuit 100 to provide the first reference current IC1 and the second reference current IC2 with different temperature characteristics, and under the control of the first bias voltage VA and the second bias voltage Vbias, adaptively adjust the steady-state operating point of the circuit itself according to the first reference current IC1 and the second reference current IC2, and access the input current ICIN and the first bias voltage VA through the input branch 110 in the mirror output unit 120, and access the second bias voltage Vbias through the output branch 122 and provide the output current ICOUT, wherein the input current ICIN has the same temperature characteristic as the first reference current IC1, and the output current ICOUT has the same temperature characteristic as the second reference current IC2, and the conversion ratio of the output current ICOUT provided by the mirror output unit 120 to the input current ICIN is mirror-set to the ratio of the first reference current IC1 and the second reference current IC2 shown in formula (5). Thus, the current proportional relationship is constructed by using the current mirror circuit structure including bipolar junction transistors (BJT1-BJT4), so as to realize the conversion of the temperature characteristics of the current to the current, and to be suitable for the circuit application in which the current conversion voltage cannot be realized in practical application.

[0071] It should be noted that in the description of the present disclosure, it is understood that the terms "upper", "lower", "inner", etc. indicate the orientation or positional relationship, which are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure.

[0072] In addition, in this document, the terms "comprise", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of additional identical elements in the process, method, article or equipment comprising the element.

[0073] Finally, it should be noted that: obviously, the above embodiments are only examples for clearly illustrating the present disclosure, and are not limitations on the embodiments. Based on the above description, other different forms of changes or variations can also be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present disclosure.

Claims

1. A current generating circuit, characterized in that, include: The reference unit is used to provide a first reference current and a second reference current with different temperature characteristics, and under the control of a first bias voltage and a second bias voltage, adaptively adjusts the steady-state operating point of its own circuit according to the first reference current and the second reference current. as well as The mirror output unit includes an input branch and an output branch. The input branch is connected to an input current and a first bias voltage, and the output branch is connected to a second bias voltage and provides an output current. The input current has the same temperature characteristics as the first reference current, and the output current has the same temperature characteristics as the second reference current. The conversion ratio between the output current and the input current provided by the mirror output unit is mirrored to the ratio of the first reference current to the second reference current. The temperature characteristic conversion between the output current and the input current is achieved through a current mirror circuit structure of a bipolar junction transistor.

2. The current generating circuit according to claim 1, characterized in that, The reference unit includes: A first current source, a first transistor, and a second current source are provided. The first end of the first current source is connected to the power supply terminal and connected to the power supply voltage. The second end is connected in series with the first transistor and the second current source to ground. The first current source is used to provide the first reference current with the first temperature characteristics. The control terminal of the first transistor is connected to the first bias voltage. A first operational amplifier has its positive input terminal connected to the connection node between the first current source and the first transistor, its negative input terminal connected to a first reference voltage, and its output terminal connected to the control terminal of the first transistor.

3. The current generating circuit according to claim 2, characterized in that, The reference unit further includes: A third current source and a second transistor, wherein the first end of the third current source is connected to the power supply terminal and is connected to the power supply voltage, and the second end is connected in series with the second transistor to the second current source. The third current source is used to provide the second reference current with the second temperature characteristic, and the control terminal of the second transistor is connected to the second bias voltage. The second operational amplifier has its positive input terminal connected to the connection node between the third current source and the second transistor, its negative input terminal connected to the second reference voltage, and its output terminal connected to the second current source.

4. The current generating circuit according to claim 3, characterized in that, The input branch of the mirror output unit includes: The fourth current source, the third transistor, and the fifth current source are provided. The first end of the fourth current source is connected to the power supply terminal and is connected to the power supply voltage. The second end is connected in series with the third transistor and the fifth current source to ground. The fourth current source is used to generate the input current with the first temperature characteristic. The control terminal of the third transistor is connected to the first bias voltage. The third operational amplifier has its positive input terminal connected to the connection node between the fourth current source and the third transistor, its negative input terminal connected to the third reference voltage, and its output terminal connected to the fifth current source.

5. The current generating circuit according to claim 4, characterized in that, The output branch of the mirror output unit includes: The fourth transistor has its first terminal serving as the output terminal of the current generating circuit to provide the output current with the second temperature characteristic, and its second terminal connected in series with the fifth current source, and its control terminal connected to the second bias voltage.

6. The current generating circuit according to claim 5, characterized in that, The second current source and / or the fifth current source are variable current sources.

7. The current generating circuit according to claim 6, characterized in that, Any one of the first transistor, the second transistor, the third transistor, and the fourth transistor is a bipolar junction transistor.

8. The current generating circuit according to claim 7, characterized in that, The first transistor, the second transistor, the third transistor, and the fourth transistor are all NPN bipolar junction transistors.

9. The current generating circuit according to claim 8, characterized in that, The conversion ratio between the output current and the input current is: ICOUT= ∗ICIN(5) Wherein, IC1 represents the first reference current, IC2 represents the second reference current, ICOUT represents the output current, and ICIN represents the input current.

10. A current detection circuit, characterized in that, include: The current generating circuit as described in any one of claims 1 to 9.

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