Current sampling range adjustable circuit and battery management system

Abstract

The utility model provides a current sampling range adjustable circuit and a battery management system.The current sampling range adjustable circuit comprises a current detection amplifier, a first resistor, a second resistor and a third resistor, the first resistor and the second resistor are connected with the forward input end and the reverse input end of the current detection amplifier respectively and are connected with a sampling resistor at the same time, and the third resistor is connected with the sampling resistor; the second end of the sampling resistor is grounded. And the third resistor is connected between the first end of the first resistor and the second end of the second resistor. The output end of the current detection amplifier is connected with the analog signal receiving end of the microcontroller. According to the circuit, the gain of the current detection amplifier is flexibly adjusted by adding the third resistor, so that the range of sampling current can be flexibly adjusted according to different input signals, the gain adjustment can be realized only through a simple resistance potential-divider network, the cost of the current sampling range adjustable circuit is effectively reduced, and the application range of the current sampling range adjustable circuit is expanded. Therefore, the flexibility and practicability of the current sampling range adjustable circuit are improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of current sampling and measurement, and in particular to a current sampling range-adjustable circuit and a battery management system. Background Art

[0002] In the field of current sampling and measurement, operational amplifiers (op amps) are key components whose performance impacts the accuracy and stability of measurement systems. Traditional op amps, with their fixed amplification factor, offer developers convenient selection options. However, this fixed-amplitude design has limitations in certain application scenarios. In particular, fixed-amplitude op amps cannot meet the requirements when flexible adjustment of the sampling current range or adaptation to varying input signals is required.

[0003] When a system requires increasing the current sampling range or achieving multiple amplification factors, the traditional solution is to design multiple operational amplifier circuits with different gains and select the appropriate gain by switching the circuits. This increases the complexity of the circuit design, leading to an increase in the number of components and increased difficulty in PCB layout. It may also introduce more noise and interference, affecting the overall system performance. Furthermore, in applications requiring multiple amplification factors, using a fixed-factor design can significantly increase the number of components, thereby increasing material costs and manufacturing complexity, making it unsuitable for large-scale production applications. Utility Model Content

[0004] The purpose of the present disclosure is to overcome the deficiencies in the prior art and to provide a circuit and a battery management system with a simple structure, low cost and adjustable current sampling range.

[0005] The purpose of this disclosure is achieved through the following technical solutions:

[0006] A current sampling range adjustable circuit includes a current detection amplifier, a first resistor, a second resistor, and a third resistor, wherein the first end of the first resistor is connected to the positive input end of the current detection amplifier, the second end of the first resistor is used to be connected to the first end of the sampling resistor, the first end of the second resistor is connected to the negative input end of the current detection amplifier, the second end of the second resistor is used to be connected to the second end of the sampling resistor, and the second end of the sampling resistor is connected to the ground end.

[0007] The first end of the third resistor is connected to the first end of the first resistor, the second end of the third resistor is connected to the second end of the second resistor, and the output end of the current detection amplifier is used to connect to the analog signal receiving end of the microcontroller.

[0008] In one embodiment, the current sampling range adjustable circuit further includes a first capacitor, a first end of the first capacitor is connected to the positive input end of the current detection amplifier, and a second end of the first capacitor is connected to the first end of the second resistor.

[0009] In one embodiment, the current sampling range adjustable circuit further includes a second capacitor, a first end of the second capacitor is connected to the power input end of the current detection amplifier, and a second end of the second capacitor is connected to the ground end of the current detection amplifier.

[0010] In one embodiment, the current sampling range adjustable circuit further includes a voltage regulator, wherein the cathode of the voltage regulator is used to be connected to the external power supply terminal, the reference voltage output terminal of the voltage regulator is connected to the reference voltage detection terminal of the current detection amplifier, and the anode of the voltage regulator is grounded.

[0011] In one embodiment, the current sampling range adjustable circuit further includes a fourth resistor, a first end of the fourth resistor being connected to the reference voltage output end of the voltage regulator and the reference voltage detection end of the current detection amplifier, respectively, and a second end of the fourth resistor being connected to the positive input end of the current detection amplifier.

[0012] In one embodiment, the current sampling range adjustable circuit further includes a third capacitor, a first end of the third capacitor is connected to the output end of the current detection amplifier, and a second end of the third capacitor is connected to the ground end.

[0013] In one embodiment, the current sampling range adjustable circuit further includes a fifth resistor, a first end of the fifth resistor is used to be connected to an external power supply end, and a second end of the fifth resistor is connected to a reference voltage detection end of the current detection amplifier.

[0014] In one embodiment, the current sampling range adjustable circuit further includes a sixth resistor, a first end of the sixth resistor is connected to the output end of the current detection amplifier, and a second end of the sixth resistor is used to connect to the analog signal receiving end of the microcontroller.

[0015] In one embodiment, the current detection amplifier is TP181A1.

[0016] A battery management system includes the current sampling range adjustable circuit as described in any one of the above items.

[0017] Compared with the prior art, the present disclosure has at least the following advantages:

[0018] 1. The above-mentioned current sampling range adjustable circuit realizes flexible adjustment of the gain of the current detection amplifier by adding a voltage divider resistor, overcoming the limitations of the fixed magnification design, so that the current sampling range adjustable circuit can flexibly adjust the range of the sampling current according to different input signals, and avoids complex controllers or additional circuit designs, so that gain adjustment can be achieved through a simple resistor voltage divider network, thereby reducing the cost and complexity of the current sampling range adjustable circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 FIG. 4 is a circuit diagram of a current sampling range adjustable circuit according to an embodiment. DETAILED DESCRIPTION

[0021] To facilitate understanding of the present disclosure, a more comprehensive description of the present disclosure will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present disclosure. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. The terms used herein in the specification of this disclosure are intended only to describe specific embodiments and are not intended to limit this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] In order to better understand the technical solutions and beneficial effects of the present disclosure, the present disclosure is further described in detail below with reference to specific embodiments:

[0025] like Figure 1As shown, a current sampling range adjustable circuit 10 according to an embodiment of the present disclosure includes a current detection amplifier U1, a first resistor R1, a second resistor R2, and a third resistor R3. The first end of the first resistor R1 is connected to the positive input terminal IN+ of the current detection amplifier U1, the second end of the first resistor R1 is used to be connected to the first end SRN of the sampling resistor, the first end of the second resistor R2 is connected to the negative input terminal IN- of the current detection amplifier U1, the second end of the second resistor R2 is used to be connected to the second end SRP of the sampling resistor, and the second end SRP of the sampling resistor is connected to the ground terminal.

[0026] The first end of the third resistor R3 is connected to the first end of the first resistor R1, the second end of the third resistor R3 is connected to the second end of the second resistor R2, and the output end OUT of the current detection amplifier U1 is used to connect to the analog signal receiving end AD-CUR1 of the microcontroller.

[0027] In this embodiment, the first end of the first resistor R1 is connected to the positive input terminal IN+ of the current detection amplifier U1, and the second end of the first resistor R1 is connected to the first end SRN of the sampling resistor. The first end of the second resistor R2 is connected to the negative input terminal IN- of the current detection amplifier U1, and the second end of the second resistor R2 is connected to the second end SRP of the sampling resistor. The second end SRP of the sampling resistor forms a current loop through the ground terminal. When an external current passes through the sampling resistor, a voltage drop is generated across the sampling resistor, which serves as the input signal for the current detection amplifier U1. In the initial state, the gain of the current detection amplifier U1 is fixed internally. When the system needs to display a high current, a third resistor R3 with the same resistance as the first resistor R1 and the second resistor R2 is connected. Together with the first resistor R1 and the second resistor R2, it forms a voltage divider network. When current flows from the second end SRP of the sampling resistor to the first end SRN, the voltage at the first end SRN of the sampling resistor, which is input to the positive input terminal IN+ of the current detection amplifier U1, is reduced by half due to the voltage divider effect of the third resistor R3, thereby halving the input voltage detected by the current detection amplifier U1. Similarly, when current flows from the first terminal SRN of the sampling resistor to the second terminal SRP, the voltage input from the first terminal SRN of the sampling resistor to the inverting input terminal IN- of the current sensing amplifier U1 is also halved due to the voltage divider effect of the third resistor R3. Therefore, the input voltage is regulated through the voltage divider network, thereby adjusting the gain of the current sensing amplifier U1.

[0028] Furthermore, the relationship between the detection current and gain of the current detection amplifier U1 is as follows: OUT =(I LOAD *R SHUNT )*GAIN+V REF , where R SHUNT and V REFThe value is relatively fixed. When the current detected by the circuit has a larger range requirement, the input voltage is reduced through the voltage divider network, which is equivalent to reducing the gain of the amplifier, thereby allowing a larger current to be measured without saturating the output voltage, so that the current detection amplifier U1 can handle a larger current I LOAD range, thereby realizing the function of improving the current sampling range.

[0029] The above-mentioned current sampling range adjustable circuit 10 realizes flexible adjustment of the gain of the current detection amplifier U1 by adding a voltage divider resistor, overcoming the limitations of the fixed magnification design, so that the current sampling range adjustable circuit 10 can flexibly adjust the range of the sampling current according to different input signals, and avoids complex controllers or additional circuit designs, so that gain adjustment can be achieved through a simple resistor voltage divider network, thereby reducing the cost and complexity of the current sampling range adjustable circuit 10.

[0030] like Figure 1 As shown, in one embodiment, the current sampling range adjustable circuit 10 further includes a first capacitor C1, the first end of the first capacitor C1 being connected to the positive input terminal IN+ of the current detection amplifier U1, and the second end of the first capacitor C1 being connected to the first end of the second resistor R2. In this embodiment, the first capacitor C1 acts as a filter element, which can effectively filter out high-frequency noise in the input signal, thereby improving the stability of the input signal of the current detection amplifier U1, and further improving the accuracy of current sampling; in addition, the first capacitor C1 has the characteristic of storing electrical energy, which can smooth the input signal, thereby reducing the amplifier output fluctuation caused by signal mutation, thereby helping to improve the dynamic performance and response speed of the current sampling range adjustable circuit 10.

[0031] like Figure 1 As shown, in one embodiment, the current sampling range adjustable circuit 10 further includes a second capacitor C2, a first end of the second capacitor C2 being connected to the power input terminal of the current detection amplifier U1, and a second end of the second capacitor C2 being connected to the ground terminal of the current detection amplifier U1. In this embodiment, the second capacitor C2 serves as a power supply stabilizing element, which can absorb high-frequency noise and transient voltage fluctuations in the power supply line, providing a more stable power supply environment for the current detection amplifier U1, thereby reducing amplifier output errors caused by power supply instability; at the same time, because the second capacitor C2 has energy storage characteristics, in the event of insufficient power supply or transient power outage, it can provide short-term energy support for the current detection amplifier U1, thereby maintaining the normal operation of the current detection amplifier U1, thereby improving the reliability and anti-interference ability of the circuit.

[0032] like Figure 1As shown, in one embodiment, the current sampling range adjustable circuit 10 further includes a voltage regulator U2, the cathode of which is connected to an external power supply terminal, the reference voltage output terminal REF1 of the voltage regulator U2 is connected to the reference voltage detection terminal REF of the current detection amplifier U1, and the anode of the voltage regulator U2 is grounded. In this embodiment, the main function of the voltage regulator U2 is to provide a stable and adjustable reference voltage to the reference voltage detection terminal REF of the current detection amplifier U1. When the power supply voltage or load conditions in the circuit change, the voltage regulator U2 can automatically adjust the voltage at its output terminal to ensure that the output voltage is stable within a preset value. In addition, by adjusting the resistor network connected to the reference voltage output terminal REF1 of the voltage regulator U2, a stable reference voltage can be set to control the reference voltage output terminal REF1 of the voltage regulator U2 to maintain a constant voltage level.

[0033] like Figure 1 As shown, in one embodiment, the current sampling range adjustable circuit 10 also includes a fourth resistor R4, the first end of the fourth resistor R4 is respectively connected to the reference voltage output terminal REF1 of the voltage regulator U2 and the reference voltage detection terminal REF of the current detection amplifier U1, and the second end of the fourth resistor R4 is connected to the positive input terminal IN+ of the current detection amplifier U1. In this embodiment, the fourth resistor R4 is mainly used to suppress the temperature drift phenomenon of the circuit and improve the overall stability of the circuit. Among them, temperature drift refers to the phenomenon that the parameters of the components in the circuit change due to changes in ambient temperature, thereby causing the output characteristics of the circuit to shift. Specifically, the fourth resistor R4 is connected between the reference voltage detection terminal REF and the positive input terminal IN+ of the current detection amplifier U1 to form a voltage divider network. Since the input of the current detection amplifier U1 requires voltage compensation, and this voltage will drift with temperature changes, it will directly affect the output accuracy of the amplifier; the fourth resistor R4 is also connected to the reference voltage output terminal REF1 of the voltage regulator U2, thereby ensuring that a stable compensation voltage that adapts to temperature changes is obtained at the positive input terminal IN+ of the current detection amplifier U1, thereby effectively offsetting the offset voltage drift caused by temperature changes, and further reducing the impact of temperature drift on the output accuracy of the current detection amplifier U1.

[0034] like Figure 1As shown, in one embodiment, the current sampling range adjustable circuit 10 further includes a third capacitor C3, a first end of the third capacitor C3 being connected to the output terminal OUT of the current detection amplifier U1, and a second end of the third capacitor C3 being connected to the ground terminal. In this embodiment, the third capacitor C3 primarily serves as a filter capacitor at the output terminal of the current detection amplifier U1, enabling it to effectively filter out high-frequency noise and clutter in the amplifier output signal, thereby making the output signal more stable and thereby improving the accuracy of current sampling; secondly, the third capacitor C3 has an energy storage characteristic, which can provide short-term energy support when the amplifier output signal changes, thereby reducing output fluctuations caused by signal mutations and helping to improve the dynamic performance of the circuit.

[0035] like Figure 1 As shown, in one embodiment, the current sampling range adjustable circuit 10 further includes a fifth resistor R5, a first end of the fifth resistor R5 being connected to an external power supply terminal, and a second end of the fifth resistor R5 being connected to a reference voltage detection terminal REF of the current detection amplifier U1. In this embodiment, since the fifth resistor R5 is connected between the external power supply terminal and the reference voltage detection terminal REF of the current detection amplifier U1, it functions as a current limiter to limit the current provided by the external power supply terminal to the reference voltage detection terminal REF of the current detection amplifier U1, thereby protecting the amplifier from the impact of excessive current and improving the stability of the current sampling range adjustable circuit 10.

[0036] like Figure 1 As shown, in one embodiment, the current sampling range adjustable circuit 10 further includes a sixth resistor R6, a first end of the sixth resistor R6 being connected to the output terminal OUT of the current detection amplifier U1, and a second end of the sixth resistor R6 being connected to the analog signal receiving terminal AD-CUR1 of the microcontroller. In this embodiment, the sixth resistor R6 is located between the output terminal OUT of the current detection amplifier U1 and the analog signal receiving terminal AD-CUR1 of the microcontroller, and acts as a signal buffer. Since the output signal of the current detection amplifier U1 may contain certain noise or transient changes, if it is directly connected to the analog input terminal of the microcontroller, it may interfere with the normal operation of the microcontroller. In this case, the sixth resistor R6 can slow down the rapidly changing signal, so that the signal received by the microcontroller is more stable, thereby improving the stability of the current sampling range adjustable circuit 10.

[0037] like Figure 1As shown, in one embodiment, the model of the current detection amplifier U1 is TP181A1. In this embodiment, the current detection amplifier U1 is a bidirectional current detection amplifier U1 that can convert current signals into voltage signals for amplification. In the current sampling range adjustable circuit 10, the positive input terminal IN+ and the negative input terminal IN- of the current detection amplifier U1 are connected to the two ends of the sampling resistor through a first resistor R1 and a second resistor R2, respectively. When an external current passes through the sampling resistor, a voltage drop is generated across it. This voltage drop serves as the input signal of the current detection amplifier U1. In the initial state, the current detection amplifier U1 has a fixed gain internally, enabling it to amplify the input signal to a range suitable for reception and processing by the microcontroller. At the same time, by setting the voltage divider function of the third resistor R3, the gain of the current detection amplifier U1 can be flexibly adjusted to adapt to different current sampling range requirements, thereby improving the applicability and flexibility of the current detection amplifier U1.

[0038] A battery management system includes any of the above-described current sampling range adjustable circuits 10. In this embodiment, the first end of a first resistor R1 is connected to the positive input terminal IN+ of a current sensing amplifier U1, and the second end of the first resistor R1 is connected to the first end SRN of a sampling resistor. The first end of a second resistor R2 is connected to the negative input terminal IN- of the current sensing amplifier U1, and the second end of the second resistor R2 is connected to the second end SRP of the sampling resistor. The second end SRP of the sampling resistor forms a current loop through the ground terminal. When an external current passes through the sampling resistor, a voltage drop is generated across the sampling resistor, which serves as the input signal for the current sensing amplifier U1. In the initial state, the gain of the current detection amplifier U1 is fixed inside the chip; when the system needs to display a large current, a third resistor R3 with the same resistance as the first resistor R1 and the second resistor R2 is connected, and together with the first resistor R1 and the second resistor R2, it forms a voltage divider network. When the current flows from the second end SRP of the sampling resistor to the first end SRN, due to the voltage divider effect of the third resistor R3, the voltage of the first end SRN of the sampling resistor input to the positive input terminal IN+ of the current detection amplifier U1 is also reduced by half, thereby halving the input voltage detected by the current detection amplifier U1. Similarly, when the current flows from the first end SRN of the sampling resistor to the second end SRP, due to the voltage divider effect of the third resistor R3, the voltage of the first end SRN of the sampling resistor input to the negative input terminal IN- of the current detection amplifier U1 is also reduced by half, thereby achieving input voltage adjustment through the voltage divider network, thereby adjusting the gain of the current detection amplifier U1. Furthermore, the relationship between the detection current size and gain of the current detection amplifier U1 is as follows: V OUT =(I LOAD *R SHUNT )*GAIN+V REF, where R SHUNT and V REF The value is relatively fixed. When the current detected by the circuit has a larger range requirement, the input voltage is reduced through the voltage divider network, which is equivalent to reducing the gain of the amplifier, thereby allowing a larger current to be measured without saturating the output voltage, so that the current detection amplifier U1 can handle a larger current I LOAD range, thereby realizing the function of improving the current sampling range.

[0039] Compared with the prior art, the present disclosure has at least the following advantages:

[0040] 1. The above-mentioned current sampling range adjustable circuit 10 realizes flexible adjustment of the gain of the current detection amplifier U1 by adding a voltage divider resistor, overcoming the limitations of the fixed magnification design, so that the current sampling range adjustable circuit 10 can flexibly adjust the range of the sampling current according to different input signals, and avoids complex controllers or additional circuit designs, so that gain adjustment can be achieved through a simple resistor voltage divider network, thereby reducing the cost and complexity of the current sampling range adjustable circuit 10.

[0041] The above-described embodiments merely represent several implementation methods of the present disclosure. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the scope of the present disclosure, all of which fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the disclosed patent shall be determined by the appended claims.

Claims

1. A current sampling range adjustable circuit, characterized in that: The device comprises a current detection amplifier, a first resistor, a second resistor, and a third resistor, wherein a first end of the first resistor is connected to a positive input end of the current detection amplifier, a second end of the first resistor is used to be connected to a first end of a sampling resistor, a first end of the second resistor is connected to a negative input end of the current detection amplifier, a second end of the second resistor is used to be connected to a second end of the sampling resistor, and a second end of the sampling resistor is connected to a ground end; The first end of the third resistor is connected to the first end of the first resistor, the second end of the third resistor is connected to the second end of the second resistor, and the output end of the current detection amplifier is used to connect to the analog signal receiving end of the microcontroller.

2. The current sampling range adjustable circuit according to claim 1, characterized in that: The current sampling range adjustable circuit further includes a first capacitor, a first end of the first capacitor is connected to the positive input end of the current detection amplifier, and a second end of the first capacitor is connected to the first end of the second resistor.

3. The current sampling range adjustable circuit according to claim 1, characterized in that: The current sampling range adjustable circuit further includes a second capacitor, a first end of the second capacitor is connected to the power input end of the current detection amplifier, and a second end of the second capacitor is connected to the ground end of the current detection amplifier.

4. The current sampling range adjustable circuit according to claim 1, characterized in that: The current sampling range adjustable circuit also includes a voltage stabilizer, the cathode of the voltage stabilizer is used to be connected to the external power supply end, the reference voltage output end of the voltage stabilizer is connected to the reference voltage detection end of the current detection amplifier, and the anode of the voltage stabilizer is grounded.

5. The current sampling range adjustable circuit according to claim 4, characterized in that: The current sampling range adjustable circuit also includes a fourth resistor, the first end of the fourth resistor is respectively connected to the reference voltage output end of the regulator and the reference voltage detection end of the current detection amplifier, and the second end of the fourth resistor is connected to the positive input end of the current detection amplifier.

6. The current sampling range adjustable circuit according to claim 1, characterized in that: The current sampling range adjustable circuit further includes a third capacitor, a first end of the third capacitor is connected to the output end of the current detection amplifier, and a second end of the third capacitor is connected to the ground end.

7. The current sampling range adjustable circuit according to claim 1, characterized in that: The current sampling range adjustable circuit further includes a fifth resistor, a first end of the fifth resistor being connected to an external power supply end, and a second end of the fifth resistor being connected to a reference voltage detection end of the current detection amplifier.

8. The current sampling range adjustable circuit according to claim 1, characterized in that: The current sampling range adjustable circuit further includes a sixth resistor, a first end of the sixth resistor is connected to the output end of the current detection amplifier, and a second end of the sixth resistor is used to be connected to the analog signal receiving end of the microcontroller.

9. The current sampling range adjustable circuit according to claim 1, characterized in that: The model of the current detection amplifier is TP181A1.

10. A battery management system, characterized in that: The invention comprises the current sampling range adjustable circuit as described in any one of claims 1 to 9.

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