Micro-current detection circuit and detection method for large-current load switch
By employing operational amplifiers and current mirror design, the problems of process mismatch and nonlinearity in micro-current detection of high-current load switches are solved, achieving high-precision current detection suitable for modern electronic systems.
Patent Information
- Application Number
- CN202610087873.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-22
- Publication Date
- 2026-04-10
AI Technical Summary
In the existing technology, the micro-current detection of high-current load switches suffers from process mismatch between the image transistor and the power transistor, as well as nonlinear second-order effects, which leads to the deterioration of micro-current detection accuracy and makes it difficult to meet the system control requirements.
The design employs an operational amplifier, a first power transistor, a second power transistor, and a current detection module. By setting the width-to-length ratio of N:1 and K:1, a current mirror is formed. A negative feedback control loop is used to control the dynamic change of the current of the first power transistor. The second power transistor operates in the low-current and linear amplification region, thereby achieving stable current detection.
It significantly improves the accuracy and signal-to-noise ratio of microcurrent detection, alleviates the mismatch problem caused by large differences in device size, ensures the accuracy of current detection across the entire range, and reduces the dependence on expensive high-precision transistor arrays.
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Figure CN121831235A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of circuit, in particular to a micro-current detection circuit and method for large-current load switch. BACKGROUND
[0002] At present, when the current of a low-resistance large-current load switch is detected, a conventional method is to construct a mirror tube on a silicon wafer, which is matched with the power tube technology. The mirror tube and the power tube work under the same gate-source voltage, and the mirror tube generates a sampling current which is reduced by the same proportion, according to the scaled-down geometric size. However, this architecture based on fixed scaling factor has inherent limitations in practical application.
[0003] In order to meet the dual requirements of large-current current passing capability and micro-current accurate detection, the existing detection architecture using mirror tube sampling faces severe challenges. The fundamental problem is that the huge current dynamic range requires a very high proportion between the width-length ratio of the power tube and the width-length ratio of the mirror tube, for example, 1000000:1.
[0004] However, such a large size ratio significantly magnifies the inherent process mismatch and nonlinear second-order effects between the mirror tube and the power tube, causing the detection branch current to deviate seriously from the theoretical mirror relationship, and ultimately leading to a sharp deterioration of micro-current detection accuracy, which is difficult to meet the needs of system control. SUMMARY
[0005] The present application aims to at least solve the technical problems existing in the prior art. To this end, the present application proposes, in a first aspect, a micro-current detection circuit for a large-current load switch, comprising: an operational amplifier, a first power tube, a second power tube, and a current detection module, wherein: The operational amplifier is electrically connected to the first power tube, the source and the drain of the first power tube and the second power tube are connected in parallel, and are commonly connected between a power supply node and an output node; wherein the ratio between the width-length ratio of the first power tube and the width-length ratio of the second power tube is N:1, N is an integer much larger than 1; The gate of the second power tube is electrically connected to the current detection module, so that the second power tube and the current detection module form a current mirror with a ratio of K:1; wherein K is an integer much larger than 1.
[0006] In a possible implementation, the current detection module includes a mirror tube, the gate of the second power tube is electrically connected to the gate of the mirror tube, and a bias voltage is commonly connected, so that the second power tube and the mirror tube form a current mirror with a ratio of K:1.
[0007] In a possible implementation, the first power tube, the second power tube, and the mirror tube are of the same type.
[0008] In a possible implementation, the first power tube, the second power tube and the mirror tube can all be NMOS tubes or PMOS tubes.
[0009] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a reference voltage source; in the case where the first power tube, the second power tube and the mirror tube are all NMOS tubes, the non-inverting input terminal of the operational amplifier is connected to a voltage difference, the inverting input terminal of the operational amplifier is electrically connected to the reference voltage source, and the output terminal of the operational amplifier is electrically connected to the gate of the first power tube; wherein the voltage difference is determined according to the drain voltage minus the source voltage of the first power tube and the second power tube.
[0010] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a reference voltage source; in the case where the first power tube, the second power tube and the mirror tube are all PMOS tubes, the non-inverting input terminal of the operational amplifier is electrically connected to the reference voltage source, the inverting input terminal of the operational amplifier is connected to a voltage difference, and the output terminal of the operational amplifier is electrically connected to the gate of the first power tube; wherein the voltage difference is determined according to the source voltage minus the drain voltage of the first power tube and the second power tube.
[0011] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a load current source; a first end of the load current source is connected to the output node, and a second end of the load current source is grounded.
[0012] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a reference current source, and the current detection module further comprises a current detection unit; the source of the mirror tube is electrically connected to a first end of the current detection unit, the reference current source is electrically connected to a second end of the current detection unit, and an output terminal of the current detection unit is used to output a small-current detection signal; in the large load current state, the operational amplifier is used to drive the first power tube to the deep linear region; and in the small load current state, the operational amplifier is used to output a low level and control the first power tube to be completely turned off.
[0013] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a reference current source, and the current detection module further comprises a current detection unit; the drain of the mirror tube is electrically connected to a first end of the current detection unit, the reference current source is electrically connected to a second end of the current detection unit, and an output terminal of the current detection unit is used to output a small-current detection signal; in the large load current state, the operational amplifier is used to drive the first power tube to the deep linear region; and in the small load current state, the operational amplifier is used to output a high level and control the first power tube to be completely turned off.
[0014] The second aspect of the application provides a micro-current detection method for a large-current load switch, which is applied to the micro-current detection circuit for a large-current load switch in the first aspect. The micro-current detection circuit for a large-current load switch comprises an operational amplifier, a first power tube, a second power tube and a current detection module. The operational amplifier is electrically connected with the first power tube. The source and drain of the first power tube and the source and drain of the second power tube are connected in parallel with each other and are commonly connected between a power supply node and an output node. The ratio between the width-length ratio of the first power tube and the width-length ratio of the second power tube is N:1, where N is an integer much greater than 1. The gate of the second power tube is electrically connected with the current detection module, so that the second power tube and the current detection module form a K:1 ratio current mirror, where K is an integer much greater than 1. The method comprises the following steps: In a large load current state, the first power tube is driven to a deep linear region by the operational amplifier; In a small load current state, the operational amplifier outputs a low level or a high level and controls the first power tube to be completely turned off. In the case where the first power tube, the second power tube and the mirror tube are all NMOS tubes, the operational amplifier outputs a low level. In the case where the first power tube, the second power tube and the mirror tube are all PMOS tubes, the operational amplifier outputs a high level.
[0015] In a possible implementation, the current detection module comprises a mirror tube. The gate of the second power tube is electrically connected with the gate of the mirror tube and is commonly connected with a bias voltage, so that the second power tube and the mirror tube form a K:1 ratio current mirror.
[0016] In a possible implementation, the first power tube, the second power tube and the mirror tube are of the same type.
[0017] In a possible implementation, the first power tube, the second power tube and the mirror tube can all be NMOS tubes or PMOS tubes.
[0018] In a possible implementation, the micro-current detection circuit for a large-current load switch further comprises a reference voltage source. In the case where the first power tube, the second power tube and the mirror tube are all NMOS tubes, the non-inverting input terminal of the operational amplifier is connected to a voltage difference, the inverting input terminal of the operational amplifier is electrically connected with the reference voltage source, and the output terminal of the operational amplifier is electrically connected with the gate of the first power tube. The voltage difference is determined according to the drain voltage minus the source voltage of the first power tube and the second power tube.
[0019] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a reference voltage source; in the case that the first power tube, the second power tube and the mirror tube are all PMOS tubes, the non-inverting input terminal of the operational amplifier is electrically connected with the reference voltage source, the inverting input terminal of the operational amplifier is connected to the voltage difference, and the output terminal of the operational amplifier is electrically connected with the gate of the first power tube; wherein the voltage difference is determined according to the source voltage minus the drain voltage of the first power tube and the second power tube.
[0020] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a load current source; a first end of the load current source is connected to the output node, and a second end of the load current source is grounded.
[0021] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a reference current source, and the current detection module further comprises a current detection unit; the source of the mirror tube is electrically connected with a first end of the current detection unit, the reference current source is electrically connected with a second end of the current detection unit, and an output terminal of the current detection unit is used to output a small-current detection signal; in the large load current state, the operational amplifier is used to drive the first power tube to the deep linear region; in the small load current state, the operational amplifier is used to output a low level and control the first power tube to be completely turned off.
[0022] In a possible implementation, the micro-current detection circuit for the large-current load switch further comprises a reference current source, and the current detection module further comprises a current detection unit; the drain of the mirror tube is electrically connected with a first end of the current detection unit, the reference current source is electrically connected with a second end of the current detection unit, and an output terminal of the current detection unit is used to output a small-current detection signal; in the large load current state, the operational amplifier is used to drive the first power tube to the deep linear region; in the small load current state, the operational amplifier is used to output a high level and control the first power tube to be completely turned off.
[0023] The embodiments of the present application have the following beneficial effects: The embodiment of the present application provides a micro-current detection circuit and a detection method for a large-current load switch, the micro-current detection circuit for the large-current load switch comprises: an operational amplifier, a first power tube, a second power tube and a current detection module, the operational amplifier is electrically connected with the first power tube, the source and the drain of the first power tube and the second power tube are parallel to each other and are commonly connected between a power supply node and an output node, the ratio relationship between the width-length ratio of the first power tube and the width-length ratio of the second power tube is N:1, N is an integer much greater than 1, and the gate of the second power tube is electrically connected with the current detection module, so that the second power tube and the current detection module form a current mirror with a K:1 ratio, K is an integer much greater than 1. According to the scheme, the large-current path (M1) and the small-current detection path (M2-M3) are decoupled in function, the mirror current of the mirror pair M2 and M3 only needs to mirror the relatively stable and moderate current flowing through M2, and does not need to directly mirror the huge total load current, therefore, even if the overall high detection ratio is realized, the ratio coefficient K between the mirror pairs can be greatly reduced. The design greatly relieves the mismatch problem caused by the great difference in device size, and significantly improves the signal-to-noise ratio and accuracy of the mirror current in the small-current state, so as to ensure the full-range current detection accuracy from full load to light load to no load; and the scheme skillfully controls the dynamic change part of the current borne by the first power tube by using the negative feedback control loop, and makes the second power tube work in a small-current and linear amplification zone, so that the second power tube branch responsible for detection always works in an ideal condition with a gentle current change and a stable device state, therefore, the mirror tube mirroring the second power tube branch can continuously output a stable, reliable and accurate linear detection signal, effectively overcoming the nonlinearity and accuracy degradation problem caused by the device entering the subthreshold zone or being seriously affected by temperature in the traditional single power tube detection; in addition, the scheme realizes the detection accuracy not inferior to or even superior to the traditional scheme only by the optimized circuit topology without using the expensive high-precision and large-size matching transistor array, which has high application value in the modern electronic system sensitive to cost and size. BRIEF DESCRIPTION OF DRAWINGS
[0024] Figure 1 A schematic diagram of a micro-current detection circuit for a large-current load switch provided by the embodiment of the present application; Figure 2 A schematic diagram of another micro-current detection circuit for a large-current load switch provided by the embodiment of the present application; Figure 3 A schematic diagram of still another micro-current detection circuit for a large-current load switch provided by the embodiment of the present application. DETAILED DESCRIPTION
[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0026] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, the use of "based on" or "according to" implies openness and inclusiveness, because processes, steps, calculations, or other actions "based on" or "according to" one or more of the stated conditions or values may in practice be based on additional conditions or beyond the stated values.
[0027] This application provides a micro-current detection circuit for high-current load switching, such as... Figure 1 As shown, Figure 1 This application provides a schematic diagram of a micro-current detection circuit for a high-current load switch. The micro-current detection circuit includes an operational amplifier, a first power transistor, a second power transistor, and a current detection module. The operational amplifier is electrically connected to the first power transistor. The sources and drains of the first and second power transistors are connected in parallel and are jointly connected between the power supply node and the output node. The gate of the second power transistor is electrically connected to the current detection module, so that the second power transistor and the current detection module form a K:1 ratio current mirror.
[0028] The ratio between the width-to-length ratio of the first power transistor and the width-to-length ratio of the second power transistor is N:1, where N is an integer much greater than 1, and K is an integer much greater than 1.
[0029] In some alternative embodiments, the first power transistor, the second power transistor, and the mirror transistor are of the same type.
[0030] In some alternative embodiments, the first power transistor, the second power transistor, and the mirror transistor can all be NMOS transistors or PMOS transistors.
[0031] The following example illustrates the situation using NMOS transistors as the case where the first power transistor, the second power transistor, and the mirror transistor are all NMOS transistors. Figure 2 As shown, Figure 2 This is a schematic diagram of another micro-current detection circuit for a high-current load switch provided in an embodiment of this application. The circuit includes an operational amplifier U1, a first power transistor M1, and a second power transistor M2.
[0032] The operational amplifier U1 is electrically connected with the first power tube M1, the source and the drain of the first power tube M1 and the second power tube M2 are connected in parallel with each other, and are commonly connected between the power supply node Va and the output node Vc, for commonly bearing the load current source Iload.
[0033] Optionally, the proportional relationship between the width-length ratio of the first power tube M1 and the width-length ratio of the second power tube M2 is N:1, N is an integer much greater than 1, and exemplarily, N can be 1000. This proportional relationship ensures that the first power tube M1 has the low resistance capability of bearing most of the load current.
[0034] Optionally, the gate of the second power tube M2 is configured to receive a fixed bias voltage Vb, which is set to be higher than the source voltage of the second power tube M2 by a constant value, and exemplarily, the constant value can be 5V, so that the second power tube M2 stably works in the linear region of its output characteristic, and presents a fixed on-resistance Rds(on)_M2.
[0035] In some optional embodiments, the micro-current detection circuit for a large-current load switch further comprises a reference voltage source; in the case that the first power tube, the second power tube and the mirror tube are all NMOS tubes, the non-inverting input terminal of the operational amplifier is connected to the voltage difference, the inverting input terminal of the operational amplifier is electrically connected with the reference voltage source, and the output terminal of the operational amplifier is electrically connected with the gate of the first power tube; wherein the voltage difference is determined according to the drain voltage minus the source voltage of the first power tube and the second power tube.
[0036] In some optional embodiments, the micro-current detection circuit for a large-current load switch further comprises a reference voltage source; in the case that the first power tube, the second power tube and the mirror tube are all NMOS tubes, the non-inverting input terminal of the operational amplifier is connected to the voltage difference, the inverting input terminal of the operational amplifier is electrically connected with the reference voltage source, and the output terminal of the operational amplifier is electrically connected with the gate of the first power tube; wherein the voltage difference is determined according to the drain voltage minus the source voltage of the first power tube and the second power tube. Figure 2 The non-inverting input terminal of the operational amplifier U1 is connected to the reference voltage source Vref, and the inverting input terminal thereof is connected to the voltage difference between the nodes Va and Vc. And the output terminal of the operational amplifier U1 is connected to the gate of the first power tube M1, thereby forming a negative feedback control loop. The negative feedback control loop dynamically adjusts the gate voltage of M1, and forces the drain-source voltage difference (Va-Vc) to be equal to the reference voltage source Vref, i.e. Va-Vc=Vref.
[0037] And one of the parallel power tubes M1 is stabilized at the reference voltage source by the negative feedback control loop, so as to automatically adjust the resistance thereof. The other parallel power tube M2 always keeps the linear resistance unchanged, thereby realizing the autonomous and dynamic distribution of the load current source Iload between M1 and M2, so as to achieve the optimized path selection that most of the current goes through M1 when the load current is large, and most of the current goes through M2 when the load current is small; at the same time, the mirror is formed from M2 for detecting small current.
[0038] Optionally, the current detection module comprises a mirror tube M3, the gate of the second power tube M2 is electrically connected with the gate of the mirror tube M3, and the two gates are connected with a bias voltage Vb, so that the second power tube and the mirror tube form a K:1 ratio current mirror.
[0039] The ratio between the width-length ratio of the second power tube M2 and the width-length ratio of the mirror tube M3 is K:1, where K is an integer much larger than 1, and K can be 1000, for example. Therefore, the mirror tube M3 mirrors the current I_M2 of the second power tube and scales it down by a factor of K, i.e. I_M3 = I_M2 / K. The mirror current I_M3 can be guided to a subsequent processing circuit, such as a comparison with a reference current source Iref, to generate a small current detection signal for system monitoring and protection.
[0040] In some optional embodiments, referring back to Figure 2 , the micro-current detection circuit for large-current load switching further comprises a load current source Iload. The first end of the load current source Iload is connected to the output node Vc, and the second end of the load current source Iload is connected to the ground.
[0041] Optionally, referring back to Figure 2 , the micro-current detection circuit for large-current load switching further comprises a reference current source Iref, and the current detection module further comprises a current detection unit. The source of the mirror tube is electrically connected with the first end of the current detection unit, the reference current source Iref is electrically connected with the second end of the current detection unit, and the output end of the current detection unit is used to output a small current detection signal.
[0042] In some optional embodiments, referring back to Figure 2 , in a large load current state, the operational amplifier U1 is used to drive the first power tube M1 to a deep linear region, where the deep linear region is a "strengthened state" of the linear region, in which state the equivalent resistance of the first power tube M1 is more stable, and at this time M1 is equivalent to a low-internal-resistance precision resistor with controllable resistance value. In a small load current state, the operational amplifier U1 is used to output a low level and control the first power tube M1 to be completely turned off.
[0043] Specifically, based on the above Figure 2 , Vref can be set to 20 mV, N to 1000, K to 1000, Iref to 5 uA, the fixed on-resistance Rds(on)_M2 of M2 to 400 mΩ, and the minimum equivalent on-resistance Rds(on)_min_M1 of M1 in the linear region to 4 mΩ.
[0044] Next, the working mode analysis can be carried out: 1. In a large load current state, for example Iload = 5V, so that: The current flowing through M2 is fixed as: I_M2 = Vref / Rds(on)_M2 = 20mV / 400mΩ = 50mA.
[0045] The current flowing through M1 is: I_M1 ≈ 5A - 50mA = 4.95A.
[0046] At this time, the operational amplifier U1 drives M1 to the deep linear region, and its equivalent resistance Rds(on)_eff_M1 ≈ 4mΩ, to achieve high-efficiency conduction.
[0047] The current detection unit output: I_M3 = I_M2 / K = 50mA / 1000 = 50μA.
[0048] 2. In the small load current state, for example, Iload = 5mA, so that: The node voltage difference Va - Vc = Iload × Rds(on)_M2 = 5mA × 400mΩ = 2mV, which is less than Vref (20mV).
[0049] The operational amplifier U1 outputs a low level, making M1 completely off. All load current 5mA flows through M2.
[0050] The current detection unit output: I_M3 = I_M2 / K = 5mA / 1000 = 5μA.
[0051] Therefore, by monitoring the change of I_M3 in relation to Iref, the system can accurately infer the state of the load current, thereby achieving intelligent power management.
[0052] In some alternative embodiments, the following is exemplarily described with the first power tube, the second power tube, and the mirror tube being PMOS tubes, as shown in Figure 3 Figure 3 Another schematic diagram of a micro-current detection circuit for a large-current load switch provided by the embodiments of the present application. The gate of the second power tube M2 is configured to receive a fixed bias voltage Vb, which is set to be lower than the source voltage of the second power tube M2 by a constant value, exemplarily, the constant value can be 5V, so that the second power tube M2 stably works in the linear region of its output characteristic, showing a fixed on-resistance Rds(on)_M2.
[0053] In some alternative embodiments, please continue to refer to Figure 3 The micro-current detection circuit for the large-current load switch further comprises a reference voltage source; in the case that the first power tube, the second power tube and the mirror tube are all PMOS tubes, the non-inverting input terminal of the operational amplifier is electrically connected with the reference voltage source, the inverting input terminal of the operational amplifier is connected to the voltage difference, and the output terminal of the operational amplifier is electrically connected with the gate of the first power tube; wherein the voltage difference is determined according to the source voltage minus the drain voltage of the first power tube and the second power tube.
[0054] Please continue to refer to the above Figure 3 The non-inverting input terminal of the operational amplifier U1 is electrically connected with the reference voltage source, and the inverting input terminal of the operational amplifier U1 is connected to the voltage difference between the nodes Va and Vc. Optionally, please continue to refer to Figure 3 The micro-current detection circuit for the large-current load switch further comprises a reference current source Iref, and the current detection module further comprises a current detection unit. Wherein the drain of the mirror tube is electrically connected with the first end of the current detection unit, the reference current source Iref is electrically connected with the second end of the current detection unit, and the output terminal of the current detection unit is used for outputting a small current detection signal.
[0055] In some optional embodiments, please continue to refer to Figure 3 In the large load current state, the operational amplifier U1 is used for driving the first power tube M1 to the deep linear region, wherein the deep linear region is a "strengthened state" of the linear region, in which state the equivalent resistance of the first power tube M1 is more stable, at this time M1 is equivalent to a low internal resistance, resistance controllable precision resistor. In the small load current state, the operational amplifier U1 is used for outputting a high level and controlling the first power tube M1 to be completely turned off.
[0056] It should be noted that the connection mode and the specific implementation process of other components in the Figure 3 may refer to Figure 2 , which will not be described here in detail.
[0057] The application provides a micro-current detection circuit and method for a large-current load switch, the micro-current detection circuit for the large-current load switch comprising: an operational amplifier, a first power tube, a second power tube and a current detection module, the operational amplifier being electrically connected with the first power tube, the source and the drain of the first power tube and the second power tube being parallel to each other and being commonly connected between a power supply node and an output node, the ratio between the width-length ratio of the first power tube and the width-length ratio of the second power tube being N:1, N being an integer much greater than 1, the gate of the second power tube being electrically connected with the current detection module, so that the second power tube and the current detection module form a current mirror with a ratio of K:1, K being an integer much greater than 1. In the scheme, the large-current path (M1) and the small-current detection path (M2-M3) are decoupled in function, the mirror pair M2 and M3 only need to mirror the relatively stable and moderate current flowing through M2, and do not need to directly mirror the huge total load current, so that even if the overall high detection ratio is realized, the ratio coefficient K between the mirror pairs can be greatly reduced. This design greatly relieves the mismatch problem caused by the great difference in device size, and significantly improves the signal-to-noise ratio and accuracy of the mirror current in the small-current state, thereby ensuring the full-range current detection accuracy from full load to light load to no load; and the scheme skillfully uses the negative feedback control loop to control the first power tube to bear the dynamic change part of the current, and makes the second power tube work in a small-current and linear amplification zone, so that the second power tube branch responsible for detection always works in an ideal condition with a flat current change and a stable device state, and therefore the mirror tube mirroring the second power tube branch can continuously output a stable, reliable and accurate linear detection signal with respect to the load state, effectively overcoming the nonlinearity and accuracy degradation problem caused by the device entering the sub-threshold zone or being seriously affected by temperature in the traditional single power tube detection at a very small current; in addition, the scheme realizes the detection accuracy not inferior to or even superior to the traditional scheme only through the optimized circuit topology without using the expensive high-precision and large-size matching transistor array, which has high application value in modern electronic systems sensitive to cost and size.
[0058] The application further provides a micro-current detection method for a large-current load switch, which is applied to the micro-current detection circuit for the large-current load switch.
[0059] The specific implementation process and beneficial effects of the method can refer to the above-mentioned embodiments of the micro-current detection circuit for the large-current load switch, and will not be described here.
[0060] It is easy to understand that, on the basis of the several embodiments provided by the application, the skilled in the art can combine, split, recombine and obtain other embodiments, and these embodiments do not exceed the protection scope of the application.
[0061] The above detailed description has disclosed, for purposes of the embodiments of the present application, the objectives, technical solutions, and beneficial effects of the embodiments of the present application. It should be understood that the above is only a specific implementation of the embodiments of the present application, and is not intended to limit the protection scope of the embodiments of the present application. Any modification, equivalent replacement, improvement, etc. made on the basis of the technical solutions of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.
Claims
1. A micro-current detection circuit for high-current load switching, characterized in that, The micro-current detection circuit for high-current load switching includes: an operational amplifier, a first power transistor, a second power transistor, and a current detection module, wherein: The operational amplifier is electrically connected to the first power transistor. The source and drain of the first power transistor and the second power transistor are connected in parallel and are connected together between the power supply node and the output node. The ratio between the width-to-length ratio of the first power transistor and the width-to-length ratio of the second power transistor is N:1, where N is an integer much greater than 1. The gate of the second power transistor is electrically connected to the current detection module, so that the second power transistor and the current detection module form a current mirror with a ratio of K:1; where K is an integer much greater than 1.
2. The micro-current detection circuit for a high-current load switch according to claim 1, characterized in that, The current detection module includes a mirror transistor. The gate of the second power transistor is electrically connected to the gate of the mirror transistor and is connected to a common bias voltage, so that the second power transistor and the mirror transistor form a K:1 ratio current mirror.
3. The micro-current detection circuit for a high-current load switch according to claim 1 or 2, characterized in that, The first power transistor, the second power transistor, and the mirror transistor are of the same type.
4. The micro-current detection circuit for a high-current load switch according to claim 3, characterized in that, The first power transistor, the second power transistor, and the mirror transistor can all be NMOS transistors or PMOS transistors.
5. The micro-current detection circuit for a high-current load switch according to claim 4, characterized in that, The micro-current detection circuit for high-current load switching further includes a reference voltage source; when the first power transistor, the second power transistor, and the mirror transistor are all NMOS transistors, the non-inverting input terminal of the operational amplifier is connected to the voltage difference, the inverting input terminal of the operational amplifier is electrically connected to the reference voltage source, and the output terminal of the operational amplifier is electrically connected to the gate of the first power transistor; wherein, the voltage difference is determined by subtracting the source voltage from the drain voltage of the first power transistor and the second power transistor.
6. The micro-current detection circuit for a high-current load switch according to claim 4, characterized in that, The micro-current detection circuit for high-current load switching further includes a reference voltage source; when the first power transistor, the second power transistor, and the mirror transistor are all PMOS transistors, the non-inverting input terminal of the operational amplifier is electrically connected to the reference voltage source, the inverting input terminal of the operational amplifier is connected to the voltage difference, and the output terminal of the operational amplifier is electrically connected to the gate of the first power transistor; wherein, the voltage difference is determined by subtracting the drain voltage from the source voltage of the first power transistor and the second power transistor.
7. The micro-current detection circuit for a high-current load switch according to claim 3, characterized in that, The micro-current detection circuit for high-current load switching further includes a load current source; the first terminal of the load current source is connected to the output node, and the second terminal of the load current source is grounded.
8. The micro-current detection circuit for a high-current load switch according to claim 5, characterized in that, The micro-current detection circuit for high-current load switching further includes a reference current source, and the current detection module further includes a current detection unit; the source of the mirror transistor is electrically connected to the first terminal of the current detection unit, the reference current source is electrically connected to the second terminal of the current detection unit, and the output terminal of the current detection unit is used to output a small current detection signal; under high load current conditions, the operational amplifier is used to drive the first power transistor to the deep linear region; under low load current conditions, the operational amplifier is used to output a low level and control the first power transistor to be completely turned off.
9. The micro-current detection circuit for a high-current load switch according to claim 6, characterized in that, The micro-current detection circuit for high-current load switching further includes a reference current source, and the current detection module further includes a current detection unit; the drain of the mirror transistor is electrically connected to the first terminal of the current detection unit, the reference current source is electrically connected to the second terminal of the current detection unit, and the output terminal of the current detection unit is used to output a small current detection signal; under high load current conditions, the operational amplifier is used to drive the first power transistor to the deep linear region; under low load current conditions, the operational amplifier is used to output a high level and control the first power transistor to be completely turned off.
10. A micro-current detection method for a high-current load switch, characterized in that, The microcurrent detection method for high-current load switches is applied to the microcurrent detection circuit for high-current load switches as described in any one of claims 1-9.