Electronic circuit for mirroring a current and driver circuit

Abstract

An electronic circuit (1) is proposed for mirroring a current flowing in an input line (10) into an output line (15), wherein the electronic circuit (1) comprises a first current mirror circuit (40), a second current mirror circuit (50), a connecting line (60) between the first current mirror circuit (40) and the second current mirror circuit (50), an input transistor (20), and an output transistor (30), wherein the input line (10) is electrically connected to the gate of the input transistor (20) and the gate of the output transistor (30), wherein the source of the input transistor (20) is electrically connected to ground (70) and the drain of the input transistor (20) is electrically connected to the first current mirror circuit (40), wherein the source of the output transistor (30) is electrically connected to ground (70) and the drain of the output transistor (30) is electrically connected to the output line (15).wherein the output line (15) is connected to the first current mirror circuit (40) to provide an electrical potential to the first current mirror circuit (40), and the first current mirror circuit (40) is configured to mirror the current flowing at the drain of the input transistor (20) into the connecting line (60), and wherein the second current mirror circuit (50) is configured to mirror the current flowing in the connecting line (60) to the gate of the input transistor (20) and the gate of the output transistor (30).

Description

[0001] The invention relates to an electronic circuit for mirroring a current. State of the art

[0002] Numerous electronic circuits for current mirroring are known. These circuits often employ cascoding to adjust the output transistor voltage. This increases the complexity of the circuit. Furthermore, in the current state of the art, the transistors in such circuits require a large area to mirror correspondingly large currents.

[0003] US Patent 12,314,073 B2 describes a low-voltage cascode current mirror according to the prior art. WO 2011 / 058428 A1 discloses fast calibration schemes for light-emitting displays and stable current sources / sinks for these according to the prior art. DE 102 39064 A1 discloses a circuit arrangement for generating a current according to the prior art. Current mirrors according to the prior art are disclosed in the article entitled "A comparative study of various current mirror configurations: topologies and characteristics" by Bhawna Aggarwal, Maneesha Gupta, and AK Gupta in the journal "Microelectronics Journal," Vol. 53, 2016, pp. 134–155 (ISSN 0959-8324; https: / / doi.org / 10.1016 / j.mejo.2016.04.015). Disclosure of the invention

[0004] The invention is based on the objective of demonstrating an electronic circuit for mirroring a current that is precise even at high current intensities.

[0005] This problem is solved by an electronic circuit according to claim 1.

[0006] In particular, the problem is solved by an electronic circuit for mirroring a current flowing in an input line into an output line, wherein the electronic circuit comprises a first current mirror circuit, a second current mirror circuit, a connecting line between the first current mirror circuit and the second current mirror circuit, an input transistor, and an output transistor, wherein the input line is electrically connected to the gate of the input transistor and the gate of the output transistor, wherein the source of the input transistor is electrically connected to ground and the drain of the input transistor is electrically connected to the first current mirror circuit, wherein the source of the output transistor is electrically connected to ground and the drain of the output transistor is electrically connected to the output line.wherein the output line is connected to the first current mirror circuit to provide an electrical potential to the first current mirror circuit, and the first current mirror circuit is configured to mirror the current flowing at the drain of the input transistor into the connecting line, and wherein the second current mirror circuit is configured to mirror the current flowing in the connecting line to the gate of the input transistor and the gate of the output transistor. Furthermore, the electronic circuit exhibits a high effective gate-source voltage for large currents.

[0007] One advantage of this design is that the electronic circuit requires little space even at high currents. Furthermore, the drain voltage of the input transistor is matched to, or rather, tracked against, the drain voltage of the output transistor. The gate voltage is regulated in this process. Another advantage is that if the voltage applied to the first and / or second current mirror circuit becomes too low (so that they no longer fully reflect the respective current), the gate voltage at the output transistor increases. In this way, when the voltage at the output transistor is low, the current at the drain of the output transistor increases. The electronic circuit exhibits high precision even under temperature variations; that is, the current in the input line remains constant even at high temperatures.The input current is precisely mirrored into the output line at high current levels, so that the difference in current between the input and output lines is small, or rather, so that the ratio between the current in the output line and the current in the input line remains essentially the same. Furthermore, at low drain-source voltages (e.g., when charging and discharging capacitors), the electronic circuit automatically leaves its current source range and enters the low-resistance clamped state.

[0008] In particular, the problem is also solved by a driver circuit according to claim 13.

[0009] In particular, the task is accomplished by a driver circuit for a motor, comprising an electronic circuit as described above.

[0010] The advantage of this is that the driver circuit has a high output impedance.

[0011] According to one embodiment of the electronic circuit, the first current mirror circuit comprises a field-effect transistor and / or the second current mirror circuit comprises a field-effect transistor. The advantage of this is that the electronic circuit mirrors the current with particular precision, since the first current mirror circuit and / or the second current mirror circuit each perform a precise mirroring of the respective current.

[0012] According to one embodiment of the electronic circuit, the first current mirror circuit comprises a bipolar transistor and / or the second current mirror circuit comprises a bipolar transistor. An advantage of this is that the electronic circuit is technically very simple and cost-effective.

[0013] According to one embodiment of the electronic circuit, the first current mirror circuit is cascoded and / or the second current mirror circuit is cascoded. The advantage of this is that the first current mirror circuit and / or the second current mirror circuit reflects the respective current with high precision. This results in particularly precise regulation of the voltage at the gate terminal of the input transistor or the output transistor.

[0014] According to one embodiment of the electronic circuit, the first current mirror circuit comprises a PMOS current mirror. An advantage of this is that the electronic circuit is technically very simple. In particular, a PMOS current mirror can comprise two PMOS transistors.

[0015] According to one embodiment of the electronic circuit, the second current mirror circuit comprises an NMOS current mirror. An advantage of this is that the electronic circuit is particularly simple and reliable. An NMOS current mirror can, in particular, comprise two NMOS transistors.

[0016] According to one embodiment of the electronic circuit, the input transistor comprises a single-gate MOSFET. According to another embodiment, the output transistor also comprises a single-gate MOSFET. An advantage of this is that the electronic circuit is particularly reliable and cost-effective.

[0017] According to one embodiment of the electronic circuit, the input transistor and the output transistor are essentially identical in construction. This further increases the precision of the mirroring of the electric current from the input line to the output line by the electronic circuit. This means that the difference between the current or current intensity in the input line and in the output line is particularly small, or that the ratio between the current intensity in the input line and in the output line corresponds precisely to the specified ratio.

[0018] According to one embodiment of the electronic circuit, the first current mirror circuit and / or the second current mirror circuit are designed such that, below a predetermined voltage value applied to the respective current mirror circuit, they no longer fully mirror the current. An advantage of this is that at low voltages, the current or current intensity in the output line increases. This allows, for example, the discharge or recharge of an external electronic component to be carried out particularly quickly.

[0019] The term "mirroring the current" from a first conductor to a second conductor can be understood to mean, in particular, that the current in the second conductor is essentially equal to the current in the first conductor, or that the current in the second conductor is set or regulated to a multiple of the current in the first conductor (i.e., there is a predetermined ratio or mirroring factor between the current in the second conductor and the current in the first conductor). This can mean that (ideally) the current in the first and second conductors is equal due to the mirroring, or that (ideally) the current in the second conductor is a predetermined multiple of the current in the first conductor (e.g., twice, three times, ten times, one hundred times, etc.).

[0020] The term "connected" or "electrically connected" can be understood to mean, in particular, that an electrical short circuit exists between the points or objects, or the respective components, or the respective inputs or outputs of the components. For example, the gate terminals of the output transistor and the input transistor are connected, or electrically connected, which means that a short circuit exists between the gate terminals of the output transistor and the input transistor.

[0021] Preferred embodiments are described in the dependent claims. The invention is explained in more detail below with reference to a drawing of an exemplary embodiment. This drawing shows... Fig. 1 a schematic view of an exemplary first embodiment of the electronic circuit according to the invention.

[0022] In the following description, the same reference numbers are used for identical and similarly functioning parts.

[0023] Fig. Figure 1 shows a schematic view of an exemplary first embodiment of the electronic circuit 1 according to the invention.

[0024] The electronic circuit 1 is designed to mirror a current flowing in an input line 10 into an output line 15. This means that the currents in the input line 10 and the output line 15 can be essentially equal or in a predetermined ratio (e.g., 1:1.5, 1:2, 1:5, 1:10, 1:50, or similar).

[0025] The electronic circuit 1 includes an input transistor 20 and an output transistor 30.

[0026] The input transistor 20 comprises a field-effect transistor or is a field-effect transistor. The output transistor 30 comprises a field-effect transistor or is a field-effect transistor. The input transistor 20 may comprise a single-gate MOSFET or be a single-gate MOSFET. The output transistor 30 may comprise a single-gate MOSFET or be a single-gate MOSFET.

[0027] The drain, or drain terminal, of output transistor 30 is electrically connected to output line 15. The source, or source terminal, of output transistor 30 is connected to ground 70.

[0028] The gate or gate terminal of input transistor 20 is electrically connected to the gate or gate terminal of output transistor 30. The gate or gate terminal of input transistor 20 and the gate or gate terminal of output transistor 30 are electrically connected to input line 10.

[0029] The electronic circuit 1 also comprises two current mirror circuits 40, 50, namely a first current mirror circuit 40 and a second current mirror circuit 50. The first current mirror circuit 40 and / or the second current mirror circuit 50 can each be current mirror circuits according to the prior art.

[0030] The source or source terminal of the input transistor 20 is connected to ground 70. The drain or drain terminal of the input transistor 20 is connected to the first current mirror circuit 40.

[0031] The ground connection or supply voltage connection of the first current mirror circuit 40 is connected to the output line 15. The output line 15 thus provides a potential or voltage to the first current mirror circuit 40.

[0032] The first current mirror circuit 40 can include bipolar transistors and / or field-effect transistors. The second current mirror circuit 50 can include bipolar transistors and / or field-effect transistors.

[0033] The first current mirror circuit 40 is electrically connected to the second current mirror circuit 50 via a connecting line 60. The first current mirror circuit 40 is configured such that it mirrors the current flowing at the drain of the input transistor 20 into the connecting line 60 between the first current mirror circuit 40 and the second current mirror circuit 50. Thus, the current at the drain of the input transistor 20 can typically be essentially equal to the current in the connecting line 50. The current in the connecting line 60 is matched to the current at the drain of the input transistor 20.

[0034] The second current mirror circuit 50 is configured such that the current flowing in the connecting line 60 between the first current mirror circuit 40 and the second current mirror circuit 50 is mirrored by the second current mirror circuit 50 into the input line 10, or to the gate of the output transistor 30 and to the gate of the input transistor 20. The second current mirror circuit 50 is connected to ground 70 via its ground terminal or supply terminal.

[0035] The current at the output of the second current mirror circuit 50, which is connected to the gates, is, so to speak, adjusted to the current in the connecting line 60.

[0036] The first current mirror circuit 40 can include or be a PMOS current mirror. In particular, the first current mirror circuit 40 can include two PMOS transistors. The second current mirror circuit 50 can include or be an NMOS current mirror. In particular, the second current mirror circuit 50 can include two NMOS transistors.

[0037] In normal operation, the current that is mirrored from the second current mirror circuit 50 to the gates of the output transistor 30 and the input transistor 20 is equal to the input current or the current in the input line 10.

[0038] The voltage applied to output line 15 can be high or very high. The first current mirror circuit 40 is supplied by this voltage, or rather, this voltage is provided to the first current mirror circuit 40. Since the voltage drop from output line 15 through the first current mirror circuit 40 to the drain of the input transistor 20 is very small (this typically corresponds to the voltage drop across a transistor of the first current mirror circuit 40), the voltage at the drain of the input transistor 20 is essentially the same as that applied to output line 15. This means that the voltage difference between output line 15 and the drain of the input transistor 20 is small to very small. The difference can be, for example, less than 5%, and in particular, less than 1%.

[0039] In contrast, according to the state of the art, only a small voltage is applied to a drain of the input transistor 20 of a current mirror circuit, or a (significantly) lower voltage than in the output line 15 of the current mirror.

[0040] When the temperature of electronic circuit 1 increases, the current at the drain of input transistor 20 also increases. This increased current is mirrored to the gates of input transistor 20 and output transistor 30 via the two current mirror circuits 40 and 50. This reduces the voltage at the gates, thereby decreasing the current gain at input transistor 20 and output transistor 30, which in turn reduces the initially increased current at the drain of input transistor 20.

[0041] Electronic circuit 1 is, in effect, a regulated current mirror. The gate voltage at input transistor 20 and output transistor 30 is regulated by comparing the reflected (divided) current with a reference current. The drain voltage of input transistor 20 is adjusted to match the drain voltage of output transistor 30.

[0042] The electronic circuit 1 can be used, for example, to recharge a power MOSFET. If the voltage applied to the output line 15, and thus to the drain of the input transistor 20, becomes too low, the first current mirror circuit 40 and / or the second current mirror circuit 50 will no longer function, or will no longer function completely. This means that the current that is supposed to be mirrored from the drain terminal of the input transistor 20 to the gates by the second current mirror circuit 50 is no longer, or no longer completely, or not at the required level, provided at the output of the second current mirror circuit 50. The current output by the first current mirror circuit 40 and the second current mirror circuit 50, or flowing at the output of the second current mirror circuit 50, is lower than the current at the drain of the input transistor 20.This increases the effective current at the gates of the input transistor 20 and the output transistor 30, since the current or current intensity in the input line 10 remains constant.

[0043] The opposing current, which is supposed to be supplied by the two current mirror circuits 40 and 50, or rather at the output of the second current mirror circuit 50, is either missing, partially missing, or no longer fully present (compared to the normal state). Consequently, the voltage across the gates of the output transistor 30 and the input transistor 20 increases. As a result, more current flows through the output transistor 30, or rather at its drain (compared to when the first current mirror circuit 40 and the second current mirror circuit 50 were still fully functional). This allows the discharge of a power MOSFET to occur particularly quickly in the region where only a small voltage is supplied to the electronic circuit 1 by the power MOSFET, since the current at the drain terminal of the output transistor 30 increases in this region.

[0044] The electronic circuit 1 typically has no cascoding. This means that there is no further resistor or transistor between the output transistor 30 and the output line 15 (or the load connected to it).

[0045] However, it is conceivable that the first current mirror circuit 40 and / or the second current mirror circuit 50 is / are cascoded.

[0046] The drain-source voltage at input transistor 20 is essentially the same as the drain-source voltage at output transistor 30.

[0047] Electronic circuit 1 can be used as a motor driver. It is also conceivable that electronic circuit 1 could be used as a gate driver with current source characteristics.

[0048] Electronic circuit 1 can be an integrated electronic circuit. Reference symbol list 1 Electronic circuit 10 Entrance line 15 Output line 20 Input transistor 30 Output transistor 40 first current mirror circuit 50 second current mirror circuit 60 connecting line 70 mass

Claims

[1] Electronic circuit (1) for mirroring a current flowing in an input line (10) into an output line (15), wherein the electronic circuit (1) a first current mirror circuit (40), a second current mirror circuit (50), a connecting line (60) between the first current mirror circuit (40) and the second current mirror circuit (50), an input transistor (20) and an output transistor (30) includes wherein the input line (10) is electrically connected to the gate of the input transistor (20) and the gate of the output transistor (30), wherein the source of the input transistor (20) is electrically connected to ground (70) and the drain of the input transistor (20) is electrically connected to the first current mirror circuit (40), wherein the source of the output transistor (30) is electrically connected to ground (70) and the drain of the output transistor (30) is electrically connected to the output line (15), wherein the output line (15) is connected to the first current mirror circuit (40) to provide an electrical potential to the first current mirror circuit (40), and the first current mirror circuit (40) is designed to mirror the current flowing at the drain of the input transistor (20) into the connecting line (60), and wherein the second current mirror circuit (50) is designed to mirror the current flowing in the connecting line (60) to the gate of the input transistor (20) and the gate of the output transistor (30). [2] Electronic circuit (1) according to claim 1, wherein the first current mirror circuit (40) comprises a field effect transistor and the second current mirror circuit (50) comprises a field effect transistor. [3] Electronic circuit (1) according to claim 1, wherein the first current mirror circuit (40) comprises a field-effect transistor and the second current mirror circuit (50) comprises a bipolar transistor. [4] Electronic circuit (1) according to claim 1, wherein the first current mirror circuit (40) comprises a bipolar transistor and the second current mirror circuit (50) comprises a field-effect transistor. [5] Electronic circuit (1) according to claim 1, wherein the first current mirror circuit (40) comprises a bipolar transistor and the second current mirror circuit (50) comprises a bipolar transistor. [6] Electronic circuit (1) according to claim 1, 2 or 3, wherein the first current mirror circuit (40) comprises a PMOS current mirror. [7] Electronic circuit (1) according to claim 1, 2 or 4, wherein the second current mirror circuit (50) comprises an NMOS current mirror. [8] Electronic circuit (1) according to one of the preceding claims, wherein the first current mirror circuit (40) is cascoded and / or the second current mirror circuit (50) is cascoded. [9] Electronic circuit (1) according to one of the preceding claims, wherein the input transistor (20) comprises a single-gate MOSFET. [10] Electronic circuit (1) according to one of the preceding claims, wherein the output transistor (30) comprises a single-gate MOSFET. [11] Electronic circuit (1) according to one of the preceding claims, wherein the input transistor (20) and the output transistor (30) are essentially identical in construction. [12] Electronic circuit (1) according to one of the preceding claims, wherein the first current mirror circuit (40) and / or the second current mirror circuit (50) are designed such that the first current mirror circuit (40) and / or the second current mirror circuit (50) no longer completely mirror the respective current below a predetermined voltage value applied to the respective current mirror circuit (40, 50). [13] Driver circuit for a motor comprising an electronic circuit (1) according to one of the preceding claims.

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