Constant current source control circuit, constant current source device and electronic equipment

Abstract

The utility model relates to the technical field of power supply control, in particular to a constant current source control circuit, a constant current source device and electronic equipment. The circuit comprises a constant current driving circuit, a sampling resistor and a voltage difference sampling circuit, the first end of the constant current driving circuit is connected with an external input voltage, the second end of the constant current driving circuit is connected with the first end of the sampling resistor, the second end of the sampling resistor is connected with a load, the first end of the differential pressure sampling circuit is connected with the first end of the sampling resistor, and the second end of the differential pressure sampling circuit is connected with the second end of the sampling resistor. The third end of the voltage difference sampling circuit is connected with the third end of the constant current driving circuit; the voltage difference sampling circuit collects difference voltage at the two ends of the sampling resistor and transmits the difference voltage to the constant-current driving circuit. The constant current driving circuit adjusts external input voltage based on the difference voltage to generate driving voltage, so that the difference voltage at the two ends of the sampling resistor is kept at preset difference voltage, and the purpose of outputting constant current is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic control technical field especially relates to a constant current source control circuit, constant current source device and electronic equipment. BACKGROUND

[0002] In the application of hardware circuit, the demand of high-precision constant current source is increasing, especially in semiconductor device parameter measurement and various physical property type sensitive devices (such as heat-sensitive, force-sensitive, light-sensitive, magnetic-sensitive and humidity-sensitive sensors). These sensitive devices are usually made of semiconductor materials, and the wire resistance and contact resistance of the connector can affect its performance, and its working characteristics have very high requirements for the stability and precision of the power supply. With the change of ambient temperature, the working state of the device will also change, resulting in deviation of output current. When the external load changes greatly, the constant current source under the traditional design scheme may not be able to quickly adjust its state to maintain constant current output, thereby affecting the normal work of the subsequent circuit.

[0003] The above content is only used to assist in understanding the technical scheme of the utility model, and does not represent that the above content is prior art. UTILITY MODEL CONTENT

[0004] The main purpose of the utility model is to provide a constant current source control circuit, constant current source device and electronic equipment, which aims to solve the technical problem that the constant current source in the prior art cannot maintain constant output current when the load changes.

[0005] To achieve the above purpose, the utility model technical scheme provides a constant current source control circuit, which comprises: a constant current drive circuit, a sampling resistor and a differential voltage sampling circuit.

[0006] The first end of the constant current drive circuit is connected with an external input voltage, the second end of the constant current drive circuit is connected with the first end of the sampling resistor, the second end of the sampling resistor is connected with a load, the first end of the differential voltage sampling circuit is connected with the first end of the sampling resistor, the second end of the differential voltage sampling circuit is connected with the second end of the sampling resistor, and the third end of the differential voltage sampling circuit is connected with the third end of the constant current drive circuit.

[0007] The differential voltage sampling circuit is used for collecting the differential voltage between the two ends of the sampling resistor and transmitting the differential voltage to the constant current drive circuit.

[0008] The constant current drive circuit is used for obtaining the differential voltage, adjusting the driving voltage generated by the external input voltage based on the differential voltage, transmitting the driving voltage to the sampling resistor, so that the differential voltage is kept at a preset differential voltage.

[0009] In an embodiment, the constant current driving circuit comprises: a first resistor and a first operational amplifier;

[0010] A first end of the first resistor is connected with the external input voltage, a second end of the first resistor is connected with a non-inverting input end of the first operational amplifier, an output end of the first operational amplifier is connected with a first end of the sampling resistor, and an inverting input end of the first operational amplifier is connected with a third end of the differential voltage sampling circuit.

[0011] In an embodiment, the differential voltage sampling circuit comprises: a differential amplification unit.

[0012] A first end of the differential amplification unit is connected with a first end of the sampling resistor, a second end of the differential amplification unit is connected with a second end of the sampling resistor, and a third end of the differential amplification unit is connected with a third end of the constant current driving circuit.

[0013] The differential amplification unit is configured to collect a differential voltage between two ends of the sampling resistor, amplify the differential voltage, and transmit the amplified differential voltage to the constant current driving circuit.

[0014] In an embodiment, the differential amplification unit comprises: a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a second operational amplifier.

[0015] A first end of the second resistor is connected with a first end of the sampling resistor, a second end of the second resistor is connected with a first end of the third resistor and a non-inverting input end of the second operational amplifier, a second end of the third resistor is grounded, a first end of the fourth resistor is connected with a second end of the sampling resistor, a second end of the fourth resistor is connected with a first end of the fifth resistor and an inverting input end of the second operational amplifier, a second end of the fifth resistor is connected with a first end of the sixth resistor and an output end of the second operational amplifier, and a second end of the sixth resistor is connected with an inverting input end of the first operational amplifier.

[0016] In an embodiment, the constant current source control circuit further comprises: a microcontroller.

[0017] A first end of the microcontroller is connected with a first end of the constant current driving circuit.

[0018] The microcontroller is configured to adjust the external input voltage to adjust the preset differential voltage.

[0019] In an embodiment, the constant current source control circuit further comprises: a load sampling unit.

[0020] The first end of the load sampling unit is connected with the second end of the constant current driving circuit, and the second end of the load sampling unit is connected with the second end of the microcontroller;

[0021] The load sampling unit is used for collecting the driving voltage and calculating the resistance value of the load according to the amplitude of the driving voltage.

[0022] In an embodiment, the load sampling unit comprises a seventh resistor and an eighth resistor.

[0023] The first end of the seventh resistor is connected with the second end of the constant current driving circuit, the second end of the seventh resistor is connected with the first end of the eighth resistor and the second end of the microcontroller, and the second end of the eighth resistor is grounded.

[0024] In an embodiment, the load sampling unit comprises a first capacitor.

[0025] The first end of the first capacitor is connected with the first end of the eighth resistor, and the second end of the first capacitor is grounded.

[0026] In addition, the utility model discloses a constant current source device, the constant current source device includes the constant current source control circuit as described above.

[0027] In addition, the utility model discloses an electronic equipment, and the electronic equipment includes the constant current source device as described above.

[0028] The utility model discloses a constant current source control circuit, constant current source device and electronic equipment. The constant current source control circuit includes: constant current driving circuit, sampling resistance and differential voltage sampling circuit, the first end of constant current driving circuit is connected with external input voltage, the second end of constant current driving circuit is connected with the first end of sampling resistance, the second end of sampling resistance is connected with load, the first end of differential voltage sampling circuit is connected with the first end of sampling resistance, the second end of differential voltage sampling circuit is connected with the second end of sampling resistance, the third end of differential voltage sampling circuit is connected with the third end of constant current driving circuit, differential voltage sampling circuit is used for collecting the difference voltage of both ends of sampling resistance, and the difference voltage is transmitted to constant current driving circuit, constant current driving circuit is used for obtaining the difference voltage, and the driving voltage of external input voltage is adjusted based on the difference voltage, and the driving voltage is transmitted to sampling resistance, so that the difference voltage keeps at preset difference voltage. The difference voltage on the sampling resistance is collected to adjust the driving voltage output to the sampling resistance and the load, so that the difference voltage of both ends of the sampling resistance keeps at the preset difference voltage, and the purpose of output constant current can be realized in the case of load change. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are only some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative labor.

[0030] Figure 1 It is a structural schematic diagram of the first embodiment of the constant current source control circuit of the present application.

[0031] Figure 2 It is a circuit connection diagram of the second embodiment of the constant current source control circuit of the present application.

[0032] Figure 3 It is a circuit connection diagram of the third embodiment of the constant current source control circuit of the present application.

[0033] Figure 4 It is a circuit connection diagram of the fourth embodiment of the constant current source control circuit of the present application.

[0034] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings.

[0035] The figure number explanation: 10, constant current drive circuit; 20, differential pressure sampling circuit; 30, load sampling unit; BAT, power supply battery; R1-R8, first to eighth resistors; R0, sampling resistor; C1, first capacitor; U1, first operational amplifier; U2, second operational amplifier. DETAILED DESCRIPTION

[0036] It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0038] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0039] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the same or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor in the protection scope required by the present application.

[0040] Referring to Figure 1 , Figure 1 The structure diagram of the first embodiment of the constant current source control circuit is shown.

[0041] The first embodiment of the constant current source control circuit is provided.

[0042] In the embodiment, the constant current source control circuit comprises: a constant current driving circuit 10, a sampling resistor R0 and a differential voltage sampling circuit 20. The first end of the constant current driving circuit 10 is connected with an external input voltage VIN, the second end of the constant current driving circuit 10 is connected with the first end of the sampling resistor R0, the second end of the sampling resistor R0 is connected with a load, the first end of the differential voltage sampling circuit 20 is connected with the first end of the sampling resistor R0, the second end of the differential voltage sampling circuit 20 is connected with the second end of the sampling resistor R0, and the third end of the differential voltage sampling circuit 20 is connected with the third end of the constant current driving circuit 10.

[0043] It should be noted that the differential voltage sampling circuit 20 can be used to collect the differential voltage between the two ends of the sampling resistor R0 and transmit the differential voltage to the constant current driving circuit 10. The constant current driving circuit 10 can be used to obtain the differential voltage, adjust the driving voltage generated by the external input voltage based on the differential voltage, transmit the driving voltage to the sampling resistor R0, so that the differential voltage is kept at a preset differential voltage.

[0044] It should be understood that the differential voltage sampling circuit 20 can be a device structure with voltage sampling capability, which can collect and transmit the voltage value between the two ends of the sampling resistor R0. For example, it can be a voltage sampling chip or a sampling circuit constructed by an operational amplifier. The sampling resistor R0 and the load are connected in series, so the working current of the load passing through the sampling resistor R0 will form a potential difference between the two ends, that is, the differential voltage.

[0045] Further, the constant current driving circuit 10 can be a device structure with the ability of continuous output of electric energy, and the driving voltage is generated by adjusting the external input voltage according to the collected difference voltage, the external input voltage is the power supply signal input to the constant current driving circuit 10, and the driving voltage is the power supply signal for driving the load to work. Since the sampling resistor R0 and the load are connected in series, the resistance value of the sampling resistor R0 is unchanged, when the resistance value of the load increases, the current of the sampling resistor R0 decreases, the difference voltage decreases, and then the driving voltage of the constant current driving circuit 10 is adjusted to increase, so that the difference voltage is continuously and stably kept at the preset difference voltage; when the resistance value of the load decreases, the current of the sampling resistor increases, the difference voltage increases, and then the driving voltage of the constant current driving circuit 10 is adjusted to decrease, so that the difference voltage is continuously and stably kept at the preset difference voltage. Therefore, the current output to the load by the constant current source control circuit is always maintained at the preset difference voltage / the value of the sampling resistor. The preset difference voltage can be set according to the load demand, which is not limited in the embodiment.

[0046] The constant current source control circuit includes a constant current driving circuit 10, a sampling resistor R0 and a differential voltage sampling circuit 20. The first end of the constant current driving circuit 10 is connected with an external input voltage, the second end of the constant current driving circuit 10 is connected with the first end of the sampling resistor R0, the second end of the sampling resistor R0 is connected with a load, the first end of the differential voltage sampling circuit 20 is connected with the first end of the sampling resistor R0, the second end of the differential voltage sampling circuit 20 is connected with the second end of the sampling resistor R0, and the third end of the differential voltage sampling circuit 20 is connected with the third end of the constant current driving circuit 10. The differential voltage sampling circuit 20 is used for collecting the difference voltage between the two ends of the sampling resistor R0 and transmitting the difference voltage to the constant current driving circuit 10. The constant current driving circuit 10 is used for obtaining the difference voltage, adjusting the external input voltage to generate a driving voltage based on the difference voltage, and transmitting the driving voltage to the sampling resistor R0, so that the difference voltage is kept at a preset difference voltage. By adjusting the driving voltage output to the sampling resistor R0 and the load according to the difference voltage on the sampling resistor R0, the difference voltage between the two ends of the sampling resistor R0 is kept at the preset difference voltage, and the purpose of outputting constant current is achieved even in the case of load change.

[0047] Reference Figure 2 , Figure 2 The circuit connection diagram of the second embodiment of the constant current source control circuit is shown in the figure. The second embodiment of the constant current source control circuit is based on the first embodiment of the constant current source control circuit.

[0048] The constant current driving circuit 10 comprises a first resistor R1 and a first operational amplifier U1. The first end of the first resistor R1 is connected with the external input voltage VIN, the second end of the first resistor R1 is connected with the non-inverting input terminal of the first operational amplifier U1, the output terminal of the first operational amplifier U1 is connected with the first end of the sampling resistor R0, and the inverting input terminal of the first operational amplifier U1 is connected with the third end of the differential voltage sampling circuit 20.

[0049] Further, the differential voltage sampling circuit 20 comprises a differential voltage amplification unit. The first end of the differential voltage amplification unit is connected with the first end of the sampling resistor R0, the second end of the differential voltage amplification unit is connected with the second end of the sampling resistor R0, and the third end of the differential voltage amplification unit is connected with the third end of the constant current driving circuit 10.

[0050] It should be noted that the differential voltage amplification unit can be used to collect the differential voltage between the two ends of the sampling resistor R0, amplify the differential voltage, and transmit the amplified differential voltage to the constant current driving circuit.

[0051] It should be understood that, since the working current of the load is generally small, the differential voltage between the two ends of the sampling resistor R0 is also small, and the differential voltage needs to be amplified by a fixed amplification factor before being fed back to the constant current driving circuit 10 to improve the accuracy of the constant current output.

[0052] The differential voltage amplification unit comprises a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a second operational amplifier U2. The first end of the second resistor R2 is connected with the first end of the sampling resistor R0, the second end of the second resistor R2 is connected with the first end of the third resistor R3 and the non-inverting input terminal of the second operational amplifier U2, the second end of the third resistor R3 is grounded, the first end of the fourth resistor R4 is connected with the second end of the sampling resistor R0, the second end of the fourth resistor R4 is connected with the first end of the fifth resistor R5 and the inverting input terminal of the second operational amplifier U2, the second end of the fifth resistor R5 is connected with the first end of the sixth resistor R6 and the output terminal of the second operational amplifier U2, and the second end of the sixth resistor R6 is connected with the inverting input terminal of the first operational amplifier U1.

[0053] It should be noted that the same direction differential proportional amplification circuit formed by the second operational amplifier U2 amplifies the difference voltage according to the preset proportional amplification coefficient of the operation, and transmits the amplified difference voltage to the inverting input terminal of the first operational amplifier U1. When the load resistance value becomes larger, the difference voltage between the two ends of the sampling resistor R0 decreases, the voltage input to the inverting input terminal of the first operational amplifier U1 decreases, the voltage output at the output terminal of the first operational amplifier U1 increases, and the difference voltage between the two ends of the sampling resistor R0 is continuously and stably maintained at the preset difference voltage; when the load resistance value becomes smaller, the difference voltage between the two ends of the sampling resistor R0 increases, the voltage input to the inverting input terminal of the first operational amplifier U1 increases, the voltage output at the output terminal of the first operational amplifier U1 decreases, and the difference voltage between the two ends of the sampling resistor R0 is continuously and stably maintained at the preset difference voltage.

[0054] It should be understood that, according to the principle of "virtual short and virtual open" of the operational amplifier existing in the closed loop negative feedback circuit, there is a deep feedback of the difference voltage between the two ends of the sampling resistor for the first operational amplifier U1, the first operational amplifier U1 satisfies the virtual short characteristic, and the in-phase input terminal and the inverting input terminal can be regarded as short-circuited, since the external input voltage VIN remains unchanged, the difference voltage between the two ends of the sampling resistor is clamped to the preset difference voltage. The current output by the constant current source control circuit to the load is always maintained at the preset difference voltage / the value of the sampling resistor.

[0055] In the embodiment, the constant current driving circuit 10 comprises a first resistor R1 and a first operational amplifier U1. The differential voltage sampling circuit 20 comprises a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a second operational amplifier U2. The difference voltage on the sampling resistor R0 is collected and then negatively fed back to the first operational amplifier U1 after being amplified by the second operational amplifier U2. The difference voltage between the two ends of the sampling resistor R0 is continuously and stably maintained at the preset difference voltage. The difference voltage between the two ends of the sampling resistor R0 is maintained at the preset difference voltage, and the purpose of outputting constant current is achieved even in the case of load change. The circuit structure has low manufacturing cost, high precision and stability with feedback function.

[0056] Referring to Figure 3 , Figure 3 It is the circuit connection diagram of the third embodiment of the constant current source control circuit. The third embodiment of the constant current source control circuit is based on the above-mentioned embodiments of the constant current source control circuit.

[0057] The constant current source control circuit further comprises a microcontroller (Microcontroller Unit, MCU); a first end of the microcontroller MCU is connected with a first end of the constant current driving circuit; and the microcontroller MCU can be used for adjusting the external input voltage VIN to adjust the preset difference voltage.

[0058] It should be noted that the MCU can be an electronic device with storage and processing functions, which can perform wired and wireless communication, process input signals, and generate corresponding output signals at the corresponding output port through the pre-stored software program. Since the microcontroller MCU is arranged to adjust the external input voltage VIN, the external input voltage VIN in the first to second embodiments can be output from the power supply end of the microcontroller MCU in this embodiment DAC Alternatively, the MCU can adjust the amplitude of the power supply end output voltage V DAC .

[0059] It should be understood that according to the virtual short characteristic of the first operational amplifier U1, the clamped preset difference voltage amplitude is only related to the amplitude of the external input voltage and the transmission characteristic parameter of the first operational amplifier U1. Since the transmission characteristic parameter of the first operational amplifier U1 is fixed during use, the preset difference voltage can be adjusted by adjusting the amplitude of the external input voltage VIN, thereby changing the output current value of the constant current source control circuit.

[0060] In this embodiment, the constant current source control circuit further comprises a microcontroller MCU; the first end of the microcontroller MCU is connected with the first end of the constant current driving circuit 10; the microcontroller MCU is used to adjust the external input voltage VIN to adjust the preset difference voltage. The purpose of adjusting the constant current source output current is simple and easy to realize.

[0061] Referring to Figure 4 , Figure 4 is a structural schematic diagram of the fourth embodiment of the constant current source control circuit. The fourth embodiment of the constant current source control circuit is based on the above-mentioned embodiments of the constant current source control circuit.

[0062] In this embodiment, the constant current source control circuit further comprises a load sampling unit 30; the first end of the load sampling unit 30 is connected with the second end of the constant current driving circuit 10, and the second end of the load sampling unit 30 is connected with the second end of the microcontroller MCU.

[0063] It should be noted that the load sampling unit 30 can be used to collect the driving voltage, and calculate the resistance value of the load according to the amplitude of the driving voltage.

[0064] In a possible implementation, the load sampling unit 30 can include a seventh resistor R7 and an eighth resistor R8; a first end of the seventh resistor R7 is connected with a second end of the constant current driving circuit 10, a second end of the seventh resistor R7 is connected with a first end of the eighth resistor R8 and a second end of the microcontroller MCU, and a second end of the eighth resistor R8 is grounded.

[0065] Further, in order to avoid the influence of AC noise on the load resistance sampling result, the load sampling unit 30 can further include a first capacitor C1; a first end of the first capacitor C1 is connected with the first end of the eighth resistor R8, and a second end of the first capacitor C1 is grounded.

[0066] It should be understood that the driving voltage output by the first operational amplifier U1 is connected to the input pin of the microcontroller MCU after being divided by the seventh resistor R7 and the eighth resistor R8 and being filtered by the first capacitor C1, and the microcontroller U1 can calculate the size of the load connected to the current output end by collecting the driving voltage output by the first operational amplifier U1. The specific calculation method is as follows: assuming that the amplification factor of the non-inverting proportional amplification circuit composed of the second operational amplifier U2 is B, according to the characteristics that the non-inverting input end and the inverting input end of the operational amplifier are virtually shorted and virtually disconnected, formula one can be obtained.

[0067]

[0068] wherein, U o1 is the driving voltage output by the first operational amplifier U1, R0 is the resistance value of the sampling resistor R0, R 负载 is the resistance value of the load, B is the amplification factor of the second operational amplifier U2, U o2 is the voltage output by the second operational amplifier U2, and U DAC is the output voltage of the power supply end of the microcontroller MCU.

[0069] The voltage collected by the microcontroller satisfies formula two:

[0070]

[0071] wherein, U ADC is the driving voltage value collected by the microcontroller MCU, R7 is the resistance value of the seventh resistor R7, and R8 is the resistance value of the eighth resistor R8. According to formula one and formula two, formula three can be obtained:

[0072]

[0073] It should be understood that the microcontroller MCU can also adjust the output voltage U DACthe amplitude of the output voltage U of the power supply end, thereby reducing the current value transmitted to the load; when the resistance value of the load becomes smaller, the amplitude of the output voltage U of the power supply end is increased, thereby increasing the current value transmitted to the load to maintain the power of the load in operation. DAC the amplitude of the output voltage U of the power supply end, thereby reducing the current value transmitted to the load; when the resistance value of the load becomes smaller, the amplitude of the output voltage U of the power supply end is increased, thereby increasing the current value transmitted to the load to maintain the power of the load in operation. DAC the amplitude of the output voltage U of the power supply end, thereby reducing the current value transmitted to the load; when the resistance value of the load becomes smaller, the amplitude of the output voltage U of the power supply end is increased, thereby increasing the current value transmitted to the load to maintain the power of the load in operation.

[0074] In the embodiment, the constant current source control circuit further comprises a load sampling unit 30, a first end of the load sampling unit 30 is connected with the second end of the constant current driving circuit 10, and a second end of the load sampling unit 30 is connected with the second end of the microcontroller MCU; the load sampling unit 30 is used for collecting the driving voltage and calculating the resistance value of the load according to the amplitude of the driving voltage. The load sampling unit 30 comprises a seventh resistor R7 and an eighth resistor R8; a first end of the seventh resistor R7 is connected with the second end of the constant current driving circuit 10, a second end of the seventh resistor R7 is connected with a first end of the eighth resistor R8 and the second end of the microcontroller MCU, and a second end of the eighth resistor R8 is grounded. The size of the load can be calculated through sampling of the output voltage, and the purpose of adjusting the output current of the constant current source control circuit can be achieved according to the size of the load.

[0075] Further, the utility model embodiment further proposes a constant current source device. The constant current source device comprises the constant current source control circuit as above.

[0076] Since the electronic equipment adopts all the technical solutions of all the embodiments of the constant current source control circuit, at least all the beneficial effects brought by the technical solutions of the above embodiments are possessed, which will not be repeated here.

[0077] Further, the utility model embodiment further proposes an electronic equipment. The electronic equipment comprises the constant current source device as above.

[0078] Since the electronic equipment adopts all the technical solutions of all the embodiments of the constant current source device, at least all the beneficial effects brought by the technical solutions of the above embodiments are possessed, which will not be repeated here.

[0079] The preferred embodiments of the utility model are described above, which do not limit the patent range of the utility model, and any equivalent structural transformation made according to the contents of the utility model specification and drawings or direct / indirect application in other related technical fields under the utility model concept of the utility model is included in the patent protection range of the utility model.

Claims

1. A constant current source control circuit, characterized by comprising: The constant current source control circuit comprises a constant current driving circuit, a sampling resistor and a differential voltage sampling circuit; The first end of the constant current driving circuit is connected with an external input voltage, the second end of the constant current driving circuit is connected with the first end of the sampling resistor, the second end of the sampling resistor is connected with a load, the first end of the differential voltage sampling circuit is connected with the first end of the sampling resistor, the second end of the differential voltage sampling circuit is connected with the second end of the sampling resistor, and the third end of the differential voltage sampling circuit is connected with the third end of the constant current driving circuit; The differential voltage sampling circuit is configured to collect a differential voltage between the two ends of the sampling resistor and transmit the differential voltage to the constant current driving circuit. The constant current driving circuit is configured to obtain the differential voltage, adjust the external input voltage to generate a driving voltage based on the differential voltage, and transmit the driving voltage to the sampling resistor, so that the differential voltage is kept at a preset differential voltage.

2. The constant current source control circuit of claim 1, wherein, The constant current driving circuit comprises a first resistor and a first operational amplifier; The first end of the first resistor is connected with the external input voltage, the second end of the first resistor is connected with the non-inverting input end of the first operational amplifier, the output end of the first operational amplifier is connected with the first end of the sampling resistor, and the inverting input end of the first operational amplifier is connected with the third end of the differential voltage sampling circuit.

3. The constant current source control circuit of claim 2, wherein, The differential voltage sampling circuit comprises a differential voltage amplification unit; The first end of the differential voltage amplification unit is connected with the first end of the sampling resistor, the second end of the differential voltage amplification unit is connected with the second end of the sampling resistor, and the third end of the differential voltage amplification unit is connected with the third end of the constant current driving circuit. The differential voltage amplification unit is configured to collect a differential voltage between the two ends of the sampling resistor, amplify the differential voltage, and transmit the amplified differential voltage to the constant current driving circuit.

4. The constant current source control circuit of claim 3, wherein, The differential voltage amplification unit comprises a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a second operational amplifier; The first end of the second resistor is connected with the first end of the sampling resistor, the second end of the second resistor is connected with the first end of the third resistor and the non-inverting input end of the second operational amplifier, the second end of the third resistor is grounded, the first end of the fourth resistor is connected with the second end of the sampling resistor, the second end of the fourth resistor is connected with the first end of the fifth resistor and the inverting input end of the second operational amplifier, the second end of the fifth resistor is connected with the first end of the sixth resistor and the output end of the second operational amplifier, and the second end of the sixth resistor is connected with the inverting input end of the first operational amplifier.

5. The constant current source control circuit of claim 1, wherein, The constant current source control circuit further comprises a microcontroller; The first end of the microcontroller is connected with the first end of the constant current driving circuit. The microcontroller is configured to adjust the external input voltage to adjust the preset differential voltage.

6. The constant current source control circuit of claim 5, wherein, The constant current source control circuit further comprises a load sampling unit; The first end of the load sampling unit is connected with the second end of the constant current driving circuit, and the second end of the load sampling unit is connected with the second end of the microcontroller. The load sampling unit is used for collecting the driving voltage and calculating the resistance value of the load according to the amplitude of the driving voltage.

7. The constant current source control circuit of claim 6, wherein, The load sampling unit comprises a seventh resistor and an eighth resistor. The first end of the seventh resistor is connected with the second end of the constant current driving circuit, the second end of the seventh resistor is connected with the first end of the eighth resistor and the second end of the microcontroller, and the second end of the eighth resistor is grounded.

8. The constant current source control circuit of claim 7, wherein, The load sampling unit comprises a first capacitor. The first end of the first capacitor is connected with the first end of the eighth resistor, and the second end of the first capacitor is grounded.

9. A constant current source device, characterized by, The constant current source device comprises the constant current source control circuit according to any one of claims 1-8.

10. An electronic device, comprising: The electronic device comprises the constant current source device according to claim 9.

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