Constant current source circuit, light source controller and light source system

Abstract

The embodiment of the invention provides a constant current source circuit, a light source controller and a light source system, and relates to the technical field of machine vision, and the constant current source circuit comprises a power supply module, a main control module, a feedback module and a constant current module. The first end of the feedback module is electrically connected with the first end of the main control module, and the second end is electrically connected with one end of a load for acquiring and sending feedback information to the main control module; the first end of the constant current module is electrically connected with the power supply module, the second end is electrically connected with the second end of the main control module, and the third end is electrically connected with the other end of the load and used for converting the received control voltage into current output by the third end of the constant current module; the power supply module is used for supplying power to the first end of the constant-current module; and the main control module is used for adjusting the control voltage output to the constant current module based on the difference between the constant current value and the current value represented by the feedback information, so that the current value of the current output by the third end of the constant current module tends to the constant current value, and the actual current flowing through the connected load is constant current.

Description

Technical Field

[0001] The present application relates to the field of machine vision technology, and in particular to a constant current source circuit, a light source controller, and a light source system. Background Art

[0002] Constant current source circuits are widely used in a variety of electronic devices. When a load is connected to the constant current source circuit, it provides a constant current to the connected load. However, ensuring that the actual current flowing through each load remains constant when different loads are connected to the constant current source circuit has become a pressing technical problem. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide a constant current source circuit, a light source controller, and a light source system, so that the actual current flowing through the connected load is a constant current. The specific technical solution is as follows:

[0004] In a first aspect of an embodiment of the present application, a constant current source circuit is provided, comprising: a power supply module, a main control module, a feedback module, and a constant current module; a first end of the feedback module is electrically connected to a first end of the main control module, and a second end of the feedback module is used to electrically connect to one end of a load; a first end of the constant current module is electrically connected to the power supply module, a second end of the constant current module is electrically connected to a second end of the main control module, and a third end of the constant current module is used to electrically connect to the other end of the load;

[0005] The power supply module is used to supply power to the first end of the constant current module;

[0006] The feedback module is configured to obtain feedback information representing the actual current value of the constant current module flowing to the connected load through the second terminal of the feedback module; and output the feedback information to the first terminal of the main control module through the first terminal of the feedback module;

[0007] The constant current module is configured to convert the control voltage received by the second terminal of the constant current module into a current output by the third terminal of the constant current module;

[0008] The main control module is used to adjust the control voltage output from the second end of the main control module to the second end of the constant current module based on the difference between the preset constant current value and the current value represented by the feedback information, so that the current value of the current output from the third end of the constant current module tends to the constant current value.

[0009] Optionally, the constant current module includes a first operational amplifier, a first transistor, a first resistor, a second resistor, a second operational amplifier, a second transistor, a feedback resistor, and a third resistor; the first end of the first resistor is grounded;

[0010] The non-inverting input terminal of the first operational amplifier is electrically connected to the second terminal of the main control module, the output terminal of the first operational amplifier is electrically connected to the first terminal of the first transistor, and the inverting input terminal of the first operational amplifier is electrically connected to the second terminal of the first resistor and the second terminal of the first transistor;

[0011] The third terminal of the first transistor is electrically connected to the first terminal of the second resistor and the non-inverting input terminal of the second operational amplifier;

[0012] An inverting input terminal of the second operational amplifier is electrically connected to the first terminal of the feedback resistor, and an output terminal of the second operational amplifier is electrically connected to the first terminal of the second transistor;

[0013] The second terminal of the second transistor is used to be electrically connected to the other end of the load;

[0014] The second end of the feedback resistor is electrically connected to the first end of the third resistor and the third end of the second transistor;

[0015] The power module is electrically connected to the second end of the second resistor and the second end of the third resistor.

[0016] Optionally, when the first transistor is an N-channel enhancement-mode MOS field-effect transistor, the first end of the first transistor is a gate, the second end of the first transistor is a source, and the third end of the first transistor is a drain; when the first transistor is a triode, the first end of the first transistor is a base, the second end of the first transistor is an emitter, and the third end of the first transistor is a collector;

[0017] and / or,

[0018] When the second transistor is a P-channel enhancement-type MOS field-effect transistor, the first end of the second transistor is a gate, the second end of the second transistor is a drain, and the third end of the second transistor is a source; when the second transistor is a triode, the first end of the second transistor is a base, the second end of the second transistor is a collector, and the third end of the second transistor is an emitter.

[0019] Optionally, the resistance value of the second resistor is the same as the resistance value of the third resistor.

[0020] Optionally, the feedback module includes a sampling resistor and a signal processing unit; a first end of the signal processing unit is electrically connected to a first end of the main control module; the first end of the sampling resistor is grounded; a second end of the sampling resistor and a second end of the signal processing unit are configured to be electrically connected to one end of a load;

[0021] The signal processing unit is configured to pre-process a sampled voltage value generated on the sampling resistor by the actual current flowing through the sampling resistor to obtain feedback information; and send the feedback information to the main control module; wherein the pre-processing includes at least one of the following: filtering the sampled voltage value; amplifying the sampled voltage value; and converting the sampled voltage value into a digital signal.

[0022] Optionally, the main control module is specifically used to calculate the current value of the actual current flowing through the sampling resistor based on the feedback information; through a closed-loop control algorithm, using the difference between the calculated current value and the constant current value, with the current value of the current output from the third end of the constant current module tending to the constant current value, calculate the voltage value of the control voltage that needs to be provided to the second end of the constant current module; and output the control voltage corresponding to the calculated voltage value to the second end of the constant current module through the second end of the main control module.

[0023] Optionally, the main control module includes a data parsing unit and an output control unit;

[0024] The first end of the data parsing unit is electrically connected to the first end of the signal processing unit, and the second end of the data parsing unit is electrically connected to the first end of the output control unit;

[0025] The second end of the output control unit is electrically connected to the second end of the constant current module;

[0026] The data parsing unit is configured to, when the feedback information is a digital signal, calculate the current value of the actual current flowing through the sampling resistor based on the feedback information and the resistance value of the sampling resistor; and, when the feedback information is an analog signal, convert the feedback information into a digital signal; and calculate the current value of the actual current flowing through the sampling resistor based on the conversion result and the resistance value of the sampling resistor;

[0027] The data parsing unit is further configured to calculate, by a closed-loop control algorithm, a voltage value of a control voltage to be provided to the second terminal of the constant current module using a difference between the calculated current value and the constant current value, with the current value of the current outputted from the third terminal of the constant current module tending towards the constant current value; and to send the calculated voltage value to the first terminal of the output control unit via the second terminal of the data parsing unit;

[0028] The output control unit is used to output a control voltage corresponding to the received voltage value to the second end of the constant current module.

[0029] Optionally, the signal processing unit is further configured to:

[0030] According to a preset sampling interval, a plurality of voltage values generated on the sampling resistor by the actual current flowing through the sampling resistor are collected;

[0031] Calculate the average level of the collected multiple voltage values as the sampled voltage value.

[0032] Optionally, the constant current source circuit further includes a regulating module; a first end of the regulating module is electrically connected to the first end of the power module, a second end of the regulating module is electrically connected to the second end of the power module; a third end of the regulating module is electrically connected to the third end of the constant current module;

[0033] The power supply module is further configured to output a constant voltage to the first end of the regulating module through the first end of the power supply module;

[0034] The regulating module is used to adjust the voltage value of the voltage at the second end of the regulating module based on the voltage value of the constant voltage received at the first end of the regulating module and the voltage value of the voltage at the third end of the regulating module, so as to adjust the voltage value of the output voltage of the second end of the power supply module.

[0035] Optionally, the regulating module includes: a third operational amplifier, a transistor, a diode, a first capacitor, a fourth resistor, and a fifth resistor; the first end of the first capacitor is grounded;

[0036] The non-inverting input terminal of the third operational amplifier is electrically connected to the third terminal of the constant current module and the second terminal of the first capacitor, the output terminal of the third operational amplifier is electrically connected to the anode of the diode; the cathode of the diode is electrically connected to the base of the transistor;

[0037] A first end of the fifth resistor is grounded, and a second end of the fifth resistor is electrically connected to the first end of the power module and the collector of the transistor;

[0038] The emitter of the transistor is electrically connected to the first end of the fourth resistor and the inverting output end of the third operational amplifier; the second end of the fourth resistor is electrically connected to the second end of the power module and the first end of the constant current circuit.

[0039] Optionally, the constant current source circuit further includes a sixth resistor and a seventh resistor;

[0040] A first end of the sixth resistor is electrically connected to the base of the transistor, and a second end of the sixth resistor is electrically connected to the second end of the power module;

[0041] A first end of the seventh resistor is grounded, and a second end of the seventh resistor is electrically connected to the base of the transistor.

[0042] Optionally, the power supply module includes a DC voltage drop power supply, a filter inductor, and a filter capacitor;

[0043] The first end of the filter capacitor is grounded, and the second end of the filter capacitor is electrically connected to the first end of the filter inductor and the first end of the constant current module;

[0044] The second end of the filter inductor is electrically connected to the power output end of the DC voltage drop power supply; the second end of the fifth resistor is electrically connected to the constant voltage output end of the DC voltage drop power supply.

[0045] In a second aspect of the embodiments of the present application, a light source controller is provided, comprising any constant current source circuit described in the first aspect.

[0046] In a third aspect of an embodiment of the present application, a light source system is provided, comprising a light source controller and a light source; the light source controller and the light source are electrically connected; the light source controller comprises a constant current source circuit as described in any one of the first aspects above; the light source controller is configured to output current to the light source through the constant current source circuit; and the light source is configured to emit light under the drive of the current output by the light source controller.

[0047] An embodiment of the present application provides a constant current source circuit, which includes: a power supply module, a main control module, a feedback module, and a constant current module; the first end of the feedback module is electrically connected to the first end of the main control module, and the second end of the feedback module is used to electrically connect to one end of the load; the first end of the constant current module is electrically connected to the power supply module, the second end of the constant current module is electrically connected to the second end of the main control module, and the third end of the constant current module is used to electrically connect to the other end of the load; the feedback module is used to obtain feedback information representing the current value of the actual current flowing from the constant current module to the connected load; and send the feedback information to the main control module; the constant current module is used to convert the received control voltage into the current output by the third end of the constant current module; the main control module is used to adjust the control voltage output to the constant current module based on the difference between the preset constant current value and the current value represented by the feedback information, and the relationship between the voltage value of the control voltage received by the constant current module and the current value of the current output by the third end of the constant current module, so that the current value of the current output by the third end of the constant current module tends to the constant current value.

[0048] Based on the constant current source circuit provided by the present application, the feedback information can characterize the current value of the actual current flowing from the constant current module to the connected load. After the main control module obtains the feedback information from the feedback module, based on the difference between the constant current value and the current value represented by the feedback information, the control voltage output to the second end of the constant current module is adjusted, that is, based on the difference between the current value of the actual current flowing from the constant current module to the connected load and the constant current value, the current flowing from the constant current module to the connected load is adjusted so that the current value of the current output from the third end of the constant current module tends to the constant current value, that is, the difference between the current value of the actual current flowing through the connected load and the constant current value is reduced. In this way, when different loads are connected to the constant current source circuit, based on the constant current source circuit provided by the present application, the current value of the current flowing through the connected load can be made to tend to the constant current value, that is, the actual current flowing through the connected load is made to be a constant current.

[0049] Of course, it is not necessary to achieve all the advantages described above at the same time when implementing any product or method of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0051] Figure 1 A first circuit diagram of a constant current source circuit provided in an embodiment of the present application;

[0052] Figure 2 A second circuit diagram of the constant current source circuit provided in an embodiment of the present application;

[0053] Figure 3 A third circuit diagram of the constant current source circuit provided in an embodiment of the present application;

[0054] Figure 4 A fourth circuit diagram of the constant current source circuit provided in an embodiment of the present application;

[0055] Figure 5 A fifth circuit diagram of the constant current source circuit provided in an embodiment of the present application;

[0056] Figure 6 A schematic diagram of a constant current source circuit provided in an embodiment of the present application;

[0057] Figure 7 The embodiments of this application provide Figure 6 A circuit diagram corresponding to the schematic shown. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field based on this application are within the scope of protection of this application.

[0059] Constant current source circuits are widely used in a variety of electronic devices. When a load is connected to the constant current source circuit, it provides a constant current to the connected load. However, when different loads are connected to the constant current source circuit, the actual current flowing through the load is affected by the resistance of the currently connected load, resulting in a non-constant current. This results in large current errors and poor stability, which in turn reduces the reliability and life cycle of the electronic device.

[0060] Therefore, when different loads are connected to the constant current source circuit, in order to make the actual current flowing through the connected loads constant, that is, to improve the current accuracy, the present application provides a constant current source circuit. Figure 1 As shown, Figure 1 This is a first circuit diagram of a constant current source circuit provided in an embodiment of the present application. The constant current source circuit 10 comprises: a power supply module 101, a main control module 102, a feedback module 103, and a constant current module 104;

[0061] A first end of the feedback module 103 is electrically connected to a first end of the main control module 102, and a second end of the feedback module 103 is electrically connected to one end of the load 20; a first end of the constant current module 104 is electrically connected to the power module 101, a second end of the constant current module 104 is electrically connected to a second end of the main control module 102, and a third end of the constant current module 104 is electrically connected to the other end of the load 20;

[0062] The power supply module 101 is used to supply power to the first end of the constant current module 104;

[0063] The feedback module 103 is configured to obtain feedback information representing the actual current value of the constant current module 104 flowing to the connected load 20 through the second terminal of the feedback module 103; and output the feedback information to the first terminal of the main control module 102 through the first terminal of the feedback module 103;

[0064] The constant current module 104 is configured to convert the control voltage received at the second terminal of the constant current module 104 into a current outputted at the third terminal of the constant current module 104 ;

[0065] The main control module 102 is used to adjust the control voltage output from the second end of the main control module 102 to the second end of the constant current module 104 based on the difference between the preset constant current value and the current value represented by the feedback information, so that the current value of the current output from the third end of the constant current module 104 tends to the constant current value.

[0066] Based on the constant current source circuit 10 provided in the present application, the feedback information can characterize the current value of the actual current flowing from the constant current module 104 to the connected load 20. After the main control module 102 obtains the feedback information from the feedback module 103, based on the difference between the constant current value and the current value represented by the feedback information, the control voltage output to the second end of the constant current module 104 is adjusted, that is, based on the difference between the current value of the actual current flowing from the constant current module 104 to the connected load 20 and the constant current value, the current of the constant current module 104 flowing to the connected load 20 is adjusted so that the current value of the current output from the third end of the constant current module 104 tends to the constant current value, that is, the difference between the current value of the actual current flowing through the connected load 20 and the constant current value is reduced. In this way, when different loads 20 are connected in the constant current source circuit 10, based on the constant current source circuit provided in the present application, the current value of the current flowing through the connected load 20 can be made to tend to the constant current value, that is, the actual current flowing through the connected load 20 is made to be a constant current.

[0067] The constant current source circuit 10 can be widely used in a variety of electronic devices that require constant current drive. For example, if the electronic device can be a charging device, the load 20 can be a device to be charged that needs to be charged by the charging device, and the second end of the feedback module 103 is an interface for electrically connecting to the device to be charged, such as a battery constant current charging interface. If the electronic device can be a current output device, the load 20 can be a device to be charged that needs a specified amount of current to flow into it, and the second end of the feedback module 103 is an interface for outputting the specified amount of current, such as a current analog output interface.

[0068] The power module 101 is used to provide a constant voltage source for the first end of the constant current module 104 , that is, to power the constant current module 104 ; and the power module 101 can also power other modules, which is not limited in this application.

[0069] The power module 101 may include power supply devices such as batteries and generators, and may include, for example, a DC-DC BUCK (a step-down DC-DC converter), a lithium battery, etc., which is not limited in this application.

[0070] The main control module 102 may include an integrated circuit. For example, the integrated circuit may be an MCU (Microcontroller Unit), a DSP (Digital Signal Processor), a SOC, an FPGA (Field-Programmable Gate Array), a CPU (Central Processing Unit), etc., which is not limited in this application.

[0071] The constant current module 104 is a linear constant current source control module implemented by including multiple electronic components, and is used to convert the control voltage output by the main control module 102 into a current output by the third terminal of the constant current module 104, thereby realizing a linear constant current function. Therefore, the constant current module 104 can also be called a linear constant current module.

[0072] Through these various electronic devices, the core mechanism (i.e., negative feedback mechanism) of the constant current module 104 is jointly realized. After the current flowing into the constant current module 104 flows through the various electronic devices included in the constant current module 104, a current having a constant current value can be output from the third end of the constant current module 104. Exemplarily, the electronic devices included in the constant current module 104 can be divided into a voltage setting module and a voltage-to-current module. The voltage setting module is used to receive or generate a voltage signal, such as receiving a control voltage output from the second end of the main control module 102; the voltage-to-current module is used to convert the voltage signal received or generated by the voltage setting module into a corresponding current. The specific types of electronic devices included in the constant current module 104, as well as the electrical connection method between the various electronic devices, will be described in detail in the subsequent embodiments and will not be repeated here.

[0073] The second end of the constant current module 104 is electrically connected to the second end of the main control module 102. The control voltage output by the second end of the main control module 102 is the control voltage received by the second end of the constant current module 104. Under the control of the control voltage received by the second end of the constant current module 104, the current output by the power supply module 101 can output a current with a constant current value from the third end of the constant current module 104 after flowing through the various components in the constant current module 104. That is, the constant current module 104 can convert the control voltage received by its second end into a current output by its third end, thereby outputting a preset constant current to the currently connected load 20.

[0074] The second end of the feedback module 103 is electrically connected to the other end of the load 20. That is, the current flowing through the currently connected load 20 flows from the second end of the feedback module 103 into the feedback module 103. Therefore, the feedback module 103 can obtain feedback information representing the current value flowing through the currently connected load 20 based on the current flowing through its second end, and output the feedback information to the first end of the main control module 102 through its first end. That is, the feedback module 103 can feed back the current value of the current flowing through the load 20 to the main control module 102.

[0075] The main control module 102 can perform data analysis and calculation processing based on the difference between the current value represented by the feedback information sent by the feedback module 103 and the constant current value (hereinafter referred to as the deviation value), and determine the voltage value of the control voltage output to the constant current module 104; and communicate with the constant current module 104 through an interface, that is, output the control voltage corresponding to the determined voltage value to the constant current module 104.

[0076] That is, the main control module 102 can correct the current output to the currently connected load 20 based on the deviation value, so that the current value flowing through the currently connected load 20 tends to a constant current value, forming a closed-loop control, which can improve the accuracy and stability of the current output by the constant current source circuit 10 to the currently connected load 20. The specific manner in which the main control module 102 performs the above processing can be found in the detailed description of the subsequent embodiments and will not be repeated here.

[0077] In some embodiments, to further improve the stability of the output current of the power module 101, the power module 101 may further include a power supply peripheral circuit of a power supply device, such as a filter circuit, a voltage stabilization circuit, etc. For example, the power supply peripheral circuit may include an LC (inductor-capacitor) filter circuit. By filtering the current output by the power supply device through the LC filter circuit, interference current carried in the current output by the power supply device can be filtered out, thereby improving the stability of the current flowing into the constant current module 104.

[0078] In some embodiments, the feedback module 103 may include a sampling device for obtaining feedback information representing the current value (hereinafter referred to as the actual current value) of the actual current flowing to the connected load 20. For example, the sampling device may be a sampling resistor, a Hall effect device, etc.

[0079] For example, when the sampling device is a sampling resistor, the quotient of the voltage value of the sampling resistor (ie, the sampling voltage value in subsequent embodiments) and the resistance value of the sampling resistor is the actual current value. In this case, the sampling voltage value can be used as feedback information.

[0080] For example, when the sampling device is a Hall device, the current value of the current flowing through the Hall device can be calculated by detecting the change in magnetic field strength and the functional relationship between the magnetic field strength and the current value of the current flowing through the Hall device, that is, the actual current value. In this case, the magnetic field strength can be used as feedback information. Alternatively, in order to reduce the difficulty of subsequent processing and further improve the current accuracy, the magnetic field strength can be pre-processed by amplification, filtering, etc., and the pre-processing result can then be used as feedback information.

[0081] In some embodiments, Figure 1 Based on Figure 2 , Figure 2 This is a second circuit diagram of a constant current source circuit provided in an embodiment of the present application. The feedback module 103 includes a sampling resistor 1031 and a signal processing unit 1032. The first end of the signal processing unit 1032 is electrically connected to the first end of the main control module 102. The first end of the sampling resistor 1031 is grounded. The second end of the sampling resistor 1031 and the second end of the signal processing unit 1032 are electrically connected to one end of the load 20.

[0082] The signal processing unit 1032 is configured to pre-process the sampled voltage value generated on the sampling resistor 1031 by the actual current flowing through the sampling resistor 1031 to obtain feedback information; and output the feedback information to the first terminal of the main control module 102 .

[0083] The preprocessing includes at least one of the following: filtering the sampled voltage value; amplifying the sampled voltage value; and converting the sampled voltage value into a digital signal.

[0084] The first end of the signal processing unit 1032 is the first end of the feedback module 103 ; the second end of the sampling resistor 1031 and the second end of the signal processing unit 1032 are the second end of the feedback module 103 .

[0085] The resistance of sampling resistor 1031 is constant, and typically, the resistance of sampling resistor 1031 is relatively small, such as a few milliohms. In practical scenarios, the resistance of sampling circuit 1031 can be set to be less than a sampling resistance threshold, such as 10 milliohms. In practical scenarios, the actual current flowing through the currently connected load 20 is generally not excessively large, typically only tens of amperes, and thus the sampled voltage generated by the actual current across sampling resistor 1031 is also typically relatively small.

[0086] The signal processing unit 1032 may perform corresponding signal processing, ie, preprocessing, on the sampled voltage value according to the specific type of the circuit included in the signal processing unit 1032 .

[0087] In the case where the signal processing unit 1032 includes a filtering circuit, the preprocessing includes filtering the sampled voltage value. By filtering the sampled voltage value to retain only the signal of the required frequency, the impact of noise interference can be reduced, and the accuracy of the feedback information subsequently processed by the main control module 102 can be improved. Based on the more accurate feedback information, the accuracy of the control voltage output by the main control module 102 to the constant current module 104 is higher, and the current value of the current output by the third terminal of the constant current module 104 tends to a constant current value. In other words, the current accuracy of the current flowing through the currently connected load 20 can be improved.

[0088] When the signal processing unit 1032 includes an amplifier circuit, the preprocessing includes amplifying the sampled voltage value. By amplifying the sampled voltage value, the difficulty of subsequent processing of the feedback information by the main control module 102 can be reduced, and the accuracy of the obtained processing results can be improved, that is, the current accuracy of the current flowing through the currently connected load 20 can be improved.

[0089] When signal processing unit 1032 includes a conversion circuit, preprocessing includes converting the sampled voltage value into a digital signal, that is, performing AD (Analog-to-Digital) conversion on the sampled voltage value. After signal processing unit 1032 converts the sampled voltage value into a digital signal, main control module 102 can directly process the feedback information of the digital signal, thereby reducing the computational complexity of main control module 102 and thereby lowering the performance requirements of main control module 102.

[0090] In some embodiments, the main control module 102 is specifically used to calculate the current value of the actual current flowing through the sampling resistor 1031 based on the feedback information; through a closed-loop control algorithm, using the difference between the calculated current value and the constant current value, with the current value of the current output from the third end of the constant current module 104 tending to the constant current value, calculate the voltage value of the control voltage that needs to be provided to the second end of the constant current module 104; and output the control voltage corresponding to the calculated voltage value to the second end of the constant current module 104 through the second end of the main control module 102.

[0091] After obtaining the feedback information of the current value representing the actual current flowing from the constant current module 104 to the connected load 20, the main control module 102 can perform data analysis on the feedback information and calculate the current value; through the closed-loop control algorithm, using the deviation between the calculated current value and the constant current value, the current value output from the third end of the constant current module 104 tends to the constant current value for calculation processing, and obtains the voltage value of the control voltage that needs to be provided to the constant current module 104. The closed-loop control algorithm can be a PID (Proportional Integral Derivative) algorithm, a PWM (Pulse Width Modulation) algorithm, etc., which is not limited in this application. Then, the interface communication is performed with the constant current module 104, and the control voltage corresponding to the calculated voltage value is output to the constant current module 104.

[0092] Exemplarily, based on the conversion relationship between the voltage value of the control voltage received by the second end of the constant current module 104 and the current value of the current output by the third end of the constant current module 104 (hereinafter referred to as the current conversion relationship), according to the closed-loop control algorithm, a functional relationship is constructed between the change in the voltage value of the control voltage received by the second end of the constant current module 104 and the change in the current value of the current output by the third end of the constant current module 104. Then, the above-mentioned deviation value is substituted into the functional relationship, that is, the current value of the current output by the third end of the constant current module 104 tends to a constant current value. The voltage value of the control voltage that the main control module 102 needs to provide to the second end of the constant current module 104 can be calculated. The current conversion relationship can be obtained based on the circuit structure of the constant current module 104. The specific method of obtaining the current conversion relationship can be described in detail in the subsequent embodiments.

[0093] Exemplarily, when the closed-loop control algorithm is the above-mentioned PID algorithm, the closed-loop control algorithm may include at least one of the above-mentioned P algorithm, I algorithm, and D algorithm.

[0094] When the closed-loop control algorithm includes the aforementioned P algorithm, the main control module 102 can calculate the product of the deviation value and the proportional coefficient after obtaining the aforementioned deviation value, and use the calculated result as the voltage adjustment value. In this case, the main control module 102 simplifies the processing, can increase the speed of determining the voltage adjustment value, and thus increase the response speed of the constant current source circuit 10 in controlling the current.

[0095] When the closed-loop control algorithm includes the aforementioned I algorithm, the main control module 102 can receive multiple pieces of feedback information sent by the feedback module 103, thereby obtaining multiple deviation values. The main control module 102 can then calculate the sum of the obtained deviation values, multiply the sum by the integral coefficient, and use the calculated result as the voltage adjustment amount. That is, after a deviation value is generated, the main control module 102 can make multiple adjustments based on the generated deviation value, making full use of the generated deviation value to improve the accuracy of the current output by the constant current source circuit 10 to the currently connected load 20.

[0096] When the closed-loop control algorithm includes the aforementioned D algorithm, the main control module 102 can receive multiple feedback messages sent by the feedback module 103, that is, multiple deviation values can be obtained. The difference between the deviation values corresponding to the two most recently received feedback messages is calculated to obtain a differential value. The main control module 102 can then calculate the product of the differential value and the differential coefficient, and use the calculated result as the voltage value adjustment amount. In this case, the differential value can represent the changing trend of the deviation value. The main control module 102 determines the voltage value adjustment amount based on the differential value, so that the voltage value adjustment amount can be based on the changing trend of the deviation value to achieve pre-control of the current value of the actual current that will flow through the currently connected load 20 before the deviation value increases, thereby reducing the probability of an increase in the difference between the current value of the actual current that will flow through the currently connected load 20 and the constant current value, that is, pre-cursing the increase of the deviation value and reducing the adjustment time of the constant current source circuit 10 outputting the constant current value to the currently connected load 20 after the currently connected load 20 changes.

[0097] Then, the sum of the control voltage currently output by the main control module 102 to the constant current module 104 and the voltage adjustment amount is calculated to obtain the control voltage currently required to be provided by the main control module 102 to the second end of the constant current module 104 .

[0098] The above-mentioned proportional coefficient, integral coefficient, and differential coefficient can all be pre-set by a technician based on work experience, or can also be obtained through testing, and this application is not limited to this. For example, the above-mentioned proportional coefficient, integral coefficient, and differential coefficient can be obtained based on the above-mentioned current conversion relationship. That is, at this time, the main control module 102 can calculate the voltage value of the control voltage to be provided to the second end of the constant current module 104 based on the above-mentioned deviation value and the above-mentioned current conversion relationship.

[0099] In some embodiments, Figure 2 Based on Figure 3 , Figure 3 This is a third circuit diagram of the constant current source circuit provided in an embodiment of the present application. The main control module 102 includes a data parsing unit 1021 and an output control unit 1022;

[0100] A first end of the data parsing unit 1021 is electrically connected to a first end of the signal processing unit 1032 , and a second end of the data parsing unit 1021 is electrically connected to a first end of the output control unit 1022 ;

[0101] The second end of the output control unit 1022 is electrically connected to the second end of the constant current module 104;

[0102] The data analysis unit 1021 is configured to calculate the actual current value flowing through the sampling resistor 1031 based on the feedback information and the resistance value of the sampling resistor 1031 when the feedback information is a digital signal; and to convert the feedback information into a digital signal when the feedback information is an analog signal; and to calculate the actual current value flowing through the sampling resistor 1031 based on the conversion result and the resistance value of the sampling resistor 1031;

[0103] The data parsing unit 1021 is further configured to calculate a voltage value of a control voltage to be provided to the second terminal of the constant current module 104 by using a closed-loop control algorithm and utilizing a difference between the calculated current value and the constant current value, with the goal of making the current value outputted from the third terminal of the constant current module 104 approach the constant current value; and to transmit the calculated voltage value to the first terminal of the output control unit 1022 via the second terminal of the data parsing unit 1021;

[0104] The output control unit 1022 is configured to output a control voltage corresponding to the received voltage value to the second end of the constant current module 104 .

[0105] The first end of the data parsing unit 1021 is the first end of the main control module 102 ; the second end of the output control unit 1022 is the second end of the main control module 102 .

[0106] The data analysis unit 1021 is used to perform the aforementioned data analysis and calculation processing, that is, if the feedback information is a digital signal, the feedback information of the digital signal and the resistance value of the sampling resistor 1031 can be decoded, encoded, converted, etc. to calculate the current value of the actual current flowing through the sampling resistor 1031. Correspondingly, if the feedback information is an analog signal, the data analysis unit 1021 can convert the analog signal into a digital signal; and then calculate the current value in accordance with the above-mentioned method of calculating the actual current value based on the feedback information of the digital signal. Exemplarily, the data analysis unit 1021 can perform PCM (Pulse Code Modulation) on the analog signal to obtain a digital signal. Feedback information can also be called a sampling value.

[0107] Furthermore, the data analysis unit 1021 can also calculate the voltage value of the control voltage that needs to be provided to the constant current module 104 according to the difference between the calculated current value and the preset constant current value (i.e., the aforementioned deviation value) through a closed-loop control algorithm, with the current value of the current output from the third terminal of the constant current module 104 tending towards the constant current value. That is, when the current value of the current output from the third terminal of the constant current module 104 tends towards the constant current value, the output control unit 1022 needs to provide the voltage value of the control voltage to the constant current module 104. In other words, the data analysis unit 1021 can continuously correct the error of the current output from the third terminal of the constant current module 104 based on the actual current value indicated by the feedback information obtained by the feedback module 103.

[0108] The output control unit 1022 is configured to output a control voltage to the second terminal of the constant current module 104. For example, a user can manually set a desired control voltage value on the output control unit 1022, and the output control unit 1022 can output control voltages of different voltage values according to the user setting. Alternatively, upon receiving a voltage value sent by the data parsing unit 1021, the output control unit 1022 can also output a control voltage corresponding to the received voltage value.

[0109] Exemplarily, when the main control module 102 includes the aforementioned MCU, the data parsing unit 1021 may be an ADC (Analog-to-Digital Conversion) module, and the output control unit 1022 may be a DAC (Digital-to-Analog Conversion) module.

[0110] Based on the above processing, the feedback module 103 can obtain feedback information based on the actual current flowing through the currently connected load 20 after amplification, filtering, AD conversion and other modulation processing; the main control module 102 calculates the voltage value of the voltage output by the output control unit 1022 to the constant current module 104 based on the closed-loop control algorithm according to the feedback information so that the current value of the current output from the third terminal of the constant current module 104 tends to the constant current value, and then outputs the control voltage corresponding to the calculated voltage value to the constant current module 104, so that the current value of the current output from the third terminal of the constant current module 104 tends to the constant current value. That is, the main control module 102 corrects the voltage value of the voltage output by the output control unit 1022 to the constant current module 104 according to the feedback information to achieve closed-loop control, which can improve the accuracy of the current output from the third terminal of the constant current module 104, thereby improving the stability and service life of the electronic device.

[0111] In one implementation, when the signal processing unit 1032 collects a voltage value generated on the sampling resistor 1031 by the actual current flowing through the sampling resistor 1031 , it may use the collected voltage value as a sampled voltage value.

[0112] In another implementation, the presence of noise and other factors in actual scenarios may cause a sudden change in the voltage value generated by the actual current flowing through the sampling resistor 1031. The signal processing unit 1032 can combine the multiple collected voltage values to obtain a sampled voltage value, thereby reducing the impact of these factors and improving the accuracy of the sampled voltage value in subsequent processing.

[0113] Specifically, the signal processing unit 1032 is further configured to collect multiple voltage values generated on the sampling resistor 1031 by the actual current flowing through the sampling resistor 1031 according to a preset sampling interval; and calculate an average level of the collected multiple voltage values as a sampled voltage value.

[0114] The preset sampling interval may be determined by the performance of the electronic components in the actual scenario. For example, if the performance of the electronic components in the signal processing unit 1032 is good, the preset sampling interval may be shorter, such as 1 millisecond. If the performance of the electronic components in the signal processing unit 1032 is poor, the preset sampling interval may be longer, such as 5 milliseconds.

[0115] The signal processing unit 1032 can periodically collect multiple voltage values generated on the sampling resistor 1031 by the actual current flowing through the sampling resistor 1031 at a preset sampling interval. The signal processing unit 1032 can then calculate an average level of the collected voltage values as the sampled voltage value. For example, the sampled voltage value can be calculated as the average of the collected voltage values; alternatively, the sampled voltage value can be calculated as the median of the collected voltage values, although this application is not limited thereto.

[0116] For example, the voltage generated across the sampling resistor 1031 by the actual current flowing through the sampling resistor 1031 can be expressed as: VSENSE = I2 × RSENSE. Here, VSENSE represents the voltage across the sampling resistor 1031; I2 represents the actual current flowing through the sampling resistor 1031; and RSENSE represents the resistance of the sampling resistor 1031. The specific method for determining I2 can be found in the detailed description of the subsequent embodiments.

[0117] The signal processing unit 1032 can periodically obtain sampled voltage values. Each time a sampled voltage value is obtained, feedback information is obtained based on the sampled voltage value obtained this time, so that the main control module 102 adjusts the voltage value of the control voltage output to the constant current module 104 based on the feedback information obtained this time. The period of the signal processing unit 1032 obtaining sampled voltage values can be set based on the needs of the actual scenario. It is understood that the shorter the period of the signal processing unit 1032 obtaining sampled voltage values, the more frequently the main control module 102 adjusts the voltage value of the control voltage output to the constant current module 104, that is, the more timely the adjustment of the current output from the third terminal of the constant current module 104 is, and the higher the accuracy of the current output from the third terminal of the constant current module 104 is; the longer the period of the signal processing unit 1032 obtaining sampled voltage values, the lower the frequency of the main control module 102 adjusting the voltage value of the voltage output to the constant current module 104, the lower the performance requirements for the main control module 102, and the lower the cost of the constant current source circuit 10. Exemplarily, the period of obtaining sampled voltage values can include at least one preset sampling interval.

[0118] For example, the preset sampling interval may be 1 millisecond, and the period for obtaining the sampled voltage value may include 10 preset sampling intervals. That is, the signal processing unit 1032 may use the average of the 10 collected voltage values as the sampled voltage value every time 10 new voltage values are collected. The signal processing unit 1032 and the main control module 102 adjust the voltage value of the control voltage output to the second terminal of the constant current module 104, and the constant current module 104 converts the received control voltage into a current output from the third terminal of the constant current module 104. When 10 new voltage values are collected again, the voltage value of the control voltage output to the second terminal of the constant current module 104 is adjusted again in the above manner, and the constant current module 104 converts the received control voltage into a current output from the third terminal of the constant current module 104, and so on.

[0119] Based on the constant current source circuit provided in the present application, the signal processing unit 1032 can continuously obtain feedback information, and then, the main control module 102 can continuously correct the voltage value of the voltage output by the output control unit 1022 to the constant current module 104 according to the feedback information, thereby realizing closed-loop control, which can further improve the accuracy of the current outputted from the third terminal of the constant current module 104, thereby improving the stability and service life of the electronic device.

[0120] In some embodiments, Figure 1 Based on Figure 4 , Figure 4This is a fourth circuit diagram of a constant current source circuit provided in an embodiment of the present application. The constant current module 104 includes: a first operational amplifier 1041, a first transistor 1042, a first resistor 1043, a second resistor 1044, a second operational amplifier 1045, a second transistor 1046, a feedback resistor 1047, and a third resistor 1048; a first end of the first resistor 1043 is grounded;

[0121] The non-inverting input terminal of the first operational amplifier 1041 is electrically connected to the second terminal of the main control module 102, the output terminal of the first operational amplifier 1041 is electrically connected to the first terminal of the first transistor 1042, and the inverting input terminal of the first operational amplifier 1041 is electrically connected to the second terminal of the first resistor 1043 and the second terminal of the first transistor 1042;

[0122] The third terminal of the first transistor 1042 is electrically connected to the first terminal of the second resistor 1044 and the non-inverting input terminal of the second operational amplifier 1045;

[0123] An inverting input terminal of the second operational amplifier 1045 is electrically connected to a first terminal of the feedback resistor 1047 , and an output terminal of the second operational amplifier 1045 is electrically connected to a first terminal of the second transistor 1046 ;

[0124] The second terminal of the second transistor 1046 is used to electrically connect to the other terminal of the load 20;

[0125] The second end of the feedback resistor 1047 is electrically connected to the first end of the third resistor 1048 and the third end of the second transistor 1046;

[0126] The power module 101 is electrically connected to the second end of the second resistor 1044 and the second end of the third resistor 1048 .

[0127] The non-inverting input terminal of the first operational amplifier 1041 is the second terminal of the constant current module 104; the second terminal of the second resistor 1044 and the second terminal of the third resistor 1048 are the first terminal of the constant current module 104; the inverting input terminal of the second operational amplifier 1045 is the third terminal of the constant current module 104.

[0128] It is understandable that, in order for the operational amplifier to operate normally, an external power supply is required for the operational amplifier, that is, the first operational amplifier 1041 and the second operational amplifier 1045 also need to be powered by a power supply. The power supply can be the power supply module 101 or other power supply, and this application is not limited to this.

[0129] The main control module 102 outputs a control voltage to the non-inverting input terminal of the first operational amplifier 1041, that is, the non-inverting voltage value of the non-inverting input terminal of the first operational amplifier 1041 is the voltage value of the above-mentioned control voltage. According to the operational amplifier closed-loop characteristics of the operational amplifier, it can be known that the inverting voltage value of the inverting input terminal of the first operational amplifier 1041 is equal to the non-inverting voltage value of the first operational amplifier 1041. In addition, since the first end of the first resistor 1043 is grounded and the second end of the first resistor 1043 is electrically connected to the inverting input terminal of the first operational amplifier 1041, the voltage value on the first resistor 1043 is equal to the inverting voltage value of the first operational amplifier 1041. It can be expressed as: in, represents the in-phase voltage value of the first operational amplifier 1041; represents the inverting voltage value of the first operational amplifier 1041 ; VDAC represents the voltage value of the control voltage; VRSET represents the voltage value on the first resistor 1043 .

[0130] based on Figure 4 As can be seen, the second resistor 1044, the first transistor 1042, and the first resistor 1043 are connected in series. According to Ohm's law, the first current flowing through the second resistor 1044, the first transistor 1042, and the first resistor 1043 can be calculated. This can be expressed as: I1 = VDAC / RSET. Here, I1 represents the current value of the first current; RSET represents the resistance value of the first resistor 1043.

[0131] According to the closed-loop characteristics of the operational amplifier, the inverting voltage value at the inverting input terminal of the second operational amplifier 1045 is equal to the non-inverting voltage value at the non-inverting input terminal of the second operational amplifier 1045. This can be expressed as: in, represents the in-phase voltage value of the second operational amplifier 1045; represents the inverting voltage value of the second operational amplifier 1045.

[0132] Since the first end of the third resistor 1048 is electrically connected to the second end of the feedback resistor 1047, and the first end of the feedback resistor 1047 is electrically connected to the inverting input terminal of the second operational amplifier 1045, and since the feedback resistor 1047 clamps the inverting voltage of the second operational amplifier 1045, the voltage on the third resistor 1048 is the voltage between the power module 101 and the inverting input terminal of the second operational amplifier 1045.

[0133] Furthermore, since the second end of the second resistor 1044 is electrically connected to the power module 101 and the first end of the second resistor 1044 is electrically connected to the non-inverting input terminal of the second operational amplifier 1045, the voltage across the second resistor 1044 is equal to the voltage between the power module 101 and the non-inverting input terminal of the second operational amplifier. Since the inverting voltage value and the non-inverting voltage value of the second operational amplifier 1045 are equal, the voltage value across the second resistor 1044 is equal to the voltage value across the third resistor 1048.

[0134] Furthermore, according to Ohm's law, the ratio of the current value of the second current flowing through the third resistor 1048 to the current value of the first current flowing through the second resistor 1044 can be obtained, that is, the ratio of the resistance value of the second resistor 1044 to the resistance value of the third resistor 1048, which can be expressed as the ratio Q.

[0135] In some embodiments, the resistance of the second resistor 1044 is the same as the resistance of the third resistor 1048. That is, the above ratio Q is 1. Figure 4 It can be seen that the third resistor 1048, the second transistor 1046, and the currently connected load 20 are connected in series. According to Ohm's law, the current value of the second current flowing through the third resistor 1048, the second transistor 1046, and the currently connected load 20 can be calculated as I2 = I1 = VDAC / RSET. Where I2 represents the current value of the second current. I2 = VDAC / RSET is the current conversion relationship in the aforementioned embodiment.

[0136] Based on the circuit structure of the constant current source circuit 10 provided in this application, it can be seen that the current value of the actual current flowing from the constant current source circuit 10 to the currently connected load 20 changes linearly with the voltage value of the control voltage output by the main control module 102, and the proportional coefficient is 1 / RSET. In actual scenarios, RSET is a constant value. Therefore, the constant current source circuit 10 provided in the embodiment of the present application can achieve a constant current value for the current flowing to the currently connected load 20.

[0137] When the resistance value of the second resistor 1044 is the same as the resistance value of the third resistor 1048, resistors of the same model can be directly selected to construct the circuit, reducing the impact of the performance differences between resistors of different models and further improving the accuracy of the output current of the constant current source circuit 10.

[0138] It can be understood that when the resistance value of the second resistor 1044 is inconsistent with the resistance value of the third resistor 1048, the current value of the actual current flowing from the constant current source circuit 10 to the currently connected load 20 and the voltage value of the control voltage output by the main control module 102 still change in a linear relationship, and the proportional coefficient is Q / RSET.

[0139] It is understood that this application does not limit the specific models of each electronic device. Electronic devices and circuit units that can achieve similar functions can be used as electronic devices in the constant current source circuit 10 of this application. For example, the first transistor 1042 can be an N-channel enhancement type MOS field effect transistor; or, the first transistor 1042 can also be a triode, but is not limited to this. Similarly, the second transistor 1046 can be a P-channel enhancement type MOS field effect transistor, or a triode. This application is not limited to this.

[0140] In some embodiments, when the first transistor 1042 is an N-channel enhancement mode MOS field effect transistor, the first terminal of the first transistor 1042 is a gate, the second terminal of the first transistor 1042 is a source, and the third terminal of the first transistor 1042 is a drain; when the first transistor 1042 is a triode, the first terminal of the first transistor 1042 is a base, the second terminal of the first transistor 1042 is an emitter, and the third terminal of the first transistor 1042 is a collector;

[0141] and / or,

[0142] When the second transistor 1046 is a P-channel enhancement type MOS field effect transistor, the first end of the second transistor 1046 is the gate, the second end of the second transistor 1046 is the drain, and the third end of the second transistor 1046 is the source; when the second transistor 1046 is a triode, the first end of the second transistor 1046 is the base, the second end of the second transistor 1046 is the collector, and the third end of the second transistor 1046 is the emitter.

[0143] After selecting a transistor that can achieve the required function, the connection relationship between the selected transistor and other electronic devices in the constant current source circuit 10 can be determined according to the specific model and properties of the selected transistor and the direction of current flow in the constant current source circuit 10, that is, the correspondence between each pin of the selected transistor and each end of the aforementioned transistor can be determined.

[0144] For example, Figure 4 As shown, the direction of the first current is: from the second resistor 1044 to the first resistor 1043. That is, for the first transistor 1042, the current flows into the third terminal of the first transistor 1042, which is electrically connected to the first terminal of the second resistor 1044, and flows out of the second terminal of the first transistor 1042, which is electrically connected to the second terminal of the first resistor 1043. If the first transistor 1042 is an N-channel enhancement-type MOS field-effect transistor, the second terminal of the first transistor 1042 is the output terminal, that is, the source; the third terminal of the first transistor 1042 is the input terminal, that is, the drain; and accordingly, the first terminal of the first transistor 1042 is the base.

[0145] When the first transistor 1042 is a triode, the second end of the first transistor 1042 is the output end, that is, the emitter; the third end of the first transistor 1042 is the input end, that is, the collector; correspondingly, the first end of the first transistor 1042 is the base.

[0146] The second current flows from the third resistor 1048 to the currently connected load 20. If the second transistor 1046 is a P-channel enhancement-mode MOS field-effect transistor, the second terminal of the second transistor 1046 is the output terminal, i.e., the drain; the third terminal of the second transistor 1046 is the input terminal, i.e., the source; and accordingly, the first terminal of the second transistor 1046 is the base. If the second transistor 1046 is a triode, the second terminal of the second transistor 1046 is the output terminal, i.e., the collector; the third terminal of the second transistor 1046 is the input terminal, i.e., the emitter; and accordingly, the first terminal of the second transistor 1046 is the base.

[0147] In some embodiments, the constant current source circuit 10 further includes a regulating module. A first end of the regulating module is electrically connected to a first end of the power module 101, a second end of the regulating module is electrically connected to a second end of the power module 101; a third end of the regulating module is electrically connected to a third end of the constant current module 104;

[0148] The power module 101 is further configured to output a constant voltage to a first terminal of the regulating module via a first terminal of the power module 101;

[0149] The regulating module is used to adjust the voltage value of the voltage at the second end of the regulating module based on the voltage value of the constant voltage received at the first end of the regulating module and the voltage value of the voltage at the third end of the regulating module, so as to adjust the voltage value of the output voltage at the second end of the power supply module 101.

[0150] The regulating module can adjust the output power of the power module 101 by adjusting the voltage value of the output voltage at the second terminal of the power module 101. This reduces the power consumed by the electronic components in the constant current source circuit 10, thereby reducing the heat generated by the electronic components in the constant current source circuit 10. This reduces the number of components used for heat dissipation when designing electronic equipment, thereby reducing the design difficulty and size of the electronic equipment.

[0151] Specifically, in Figure 2 Based on Figure 5 , Figure 5 This is a fifth circuit diagram of a constant current source circuit provided in an embodiment of the present application. The constant current source circuit 10 further includes a third operational amplifier 105, a transistor 106, a diode 107, a first capacitor 108, a fourth resistor 109, and a fifth resistor 110; a first terminal of the first capacitor 108 is grounded;

[0152] The non-inverting input terminal of the third operational amplifier 105 is electrically connected to the third terminal of the constant current module 104 and the second terminal of the first capacitor 108. The output terminal of the third operational amplifier 105 is electrically connected to the anode of the diode 107. The cathode of the diode 107 is electrically connected to the base of the transistor 106.

[0153] A first end of the fifth resistor 110 is grounded, and a second end of the fifth resistor 110 is electrically connected to a first end of the power module 101 and a collector of the transistor 106;

[0154] The emitter of the transistor 106 is electrically connected to the first end of the fourth resistor 109 and the inverting output end of the third operational amplifier 105 ; the second end of the fourth resistor 109 is electrically connected to the second end of the power module 101 and the first end of the constant current circuit 104 .

[0155] The second end of the fifth resistor 110 is the first end of the regulating module; the second end of the fourth resistor 109 is the second end of the regulating module; and the non-inverting input end of the third operational amplifier 105 is the third end of the regulating module.

[0156] It is understandable that, in order for the operational amplifier to work properly, it is also necessary to connect an external power supply to the operational amplifier, that is, the third operational amplifier 105 also needs power supply. The power supply can be the power supply module 101 or other power supply, and this application is not limited to this.

[0157] It is understood that the present application does not limit the specific models of the electronic components. Any electronic device and circuit unit that can achieve similar functions can be used as the electronic device in the constant current source circuit 10 of the present application. For example, the transistor 106 can be a PNP transistor. For ease of description, the following description uses the transistor 106 as an example of a PNP transistor.

[0158] The non-inverting voltage value of the non-inverting input terminal of the third operational amplifier 105 is the sum of the voltage value of the currently connected load 20 and the voltage value of the sampling resistor 1031. According to Ohm's law, it can be expressed as: in, represents the common-mode voltage value of the third operational amplifier 105; I2 represents the current value flowing through the currently connected load 20 and the sampling resistor 1031 (i.e., the current value of the aforementioned second current); RLOAD represents the resistance value of the currently connected load 20; and RSENSE represents the resistance value of the sampling resistor 1031. As previously mentioned, in actual scenarios, the voltage value generated by the actual current on the sampling resistor 1031 is usually small, that is, RSENSE can be ignored, that is, I2×RSENSE can also be ignored. Therefore, the common-mode voltage value of the third operational amplifier 105 can be recorded as:

[0159] According to the closed-loop characteristics of the operational amplifier, the inverting voltage value at the inverting input terminal of the third operational amplifier 105 is equal to the non-inverting voltage value of the third operational amplifier 105, which can be expressed as: in, represents the inverting voltage value of the third operational amplifier 105 , and VE represents the emitter voltage of the transistor 106 .

[0160] According to KCL (Kirchhoff's Current Law) and the properties of PNP transistors, IE = IB + IC. IE is the emitter current of transistor 106; IB is the base current of transistor 106; and IC is the collector current of transistor 106. In practice, IB is relatively small, typically only in the microampere or nanoampere range, meaning it can be ignored. Therefore, based on the above: IE = IB + IC; The equation is: IE = IC = (VOUT - VE) / R4 = VFB / R5. VOUT represents the voltage output from the power module 101 to the constant current module 104; R4 represents the resistance of the fourth resistor 109; R5 represents the resistance of the fifth resistor 110; and VFB represents the voltage output from the power module 101 to the fifth resistor 110 (i.e., the voltage output from the constant voltage output terminal in subsequent embodiments).

[0161] By transforming the above equation (VOUT - VE) / R4 = VFB / R5, we obtain: VOUT = I2 × RLOAD + (R4 / R5) / VFB. Since R4, R5, and VFB are all fixed values, when I2 is fixed, VOUT and RLOAD vary in a linear relationship. This shows that, based on the circuit structure of the constant current source circuit 10 provided in the embodiment of the present application, VOUT and RLOAD vary in a linear relationship.

[0162] Therefore, when different loads 20 are connected to the constant current source circuit 10, the regulating module will dynamically adjust the voltage value of the voltage output by the power supply module 101 to the constant current module 104 based on the resistance value of the currently connected load 20, when the current value of the actual current flowing through the currently connected load 20 is a constant current value. At this time, the voltage value on the currently connected load 20 and the voltage value on the third resistor 1048 are both constant values. By regulating VOUT by the regulating module, compared to the constant voltage value output by the power supply module 101, the voltage value on the second transistor 1046 can be reduced, thereby reducing the power of the electronic components in the constant current module 104.

[0163] For example, the voltage across the third resistor 1048 is 2 volts. The preset constant current value is 1 ampere. If the constant current source circuit 10 does not include the aforementioned regulating module, the voltage output by the power module 101 is 10 volts.

[0164] If the resistance of the currently connected load 20 is 2 ohms, the voltage across the currently connected load 20 is 2 volts. If the constant current source circuit 10 does not include the aforementioned adjustment module, the voltage across the second transistor 1046 is 6 volts. At this time, the power consumed by the second transistor 1046 is the power generated at a voltage of 6 volts and a current of 1 ampere. If the constant current source circuit 10 includes the aforementioned adjustment module, the adjustment module adjusts the voltage output by the power module 101 to 8 volts. Then, the voltage across the second transistor 1046 is 4 volts. At this time, the power consumed by the second transistor 1046 is the power generated at a voltage of 4 volts and a current of 1 ampere.

[0165] If the resistance of the currently connected load 20 is 4 ohms, the voltage across the currently connected load 20 is 4 volts. If the constant current source circuit 10 does not include the aforementioned adjustment module, the voltage across the second transistor 1046 is 4 volts. At this time, the power consumed by the second transistor 1046 is the power generated at a voltage of 4 volts and a current of 1 ampere. If the constant current source circuit 10 includes the aforementioned adjustment module, the adjustment module adjusts the voltage output by the power module 101 to 8 volts. Then, the voltage across the second transistor 1046 is 2 volts. At this time, the power consumed by the second transistor 1046 is the power generated at a voltage of 2 volts and a current of 1 ampere.

[0166] Since the power consumed by the transistor is proportional to the voltage value on the transistor when the current remains unchanged, based on the above example, it can be seen that when the constant current source circuit 10 includes a regulation module, by adjusting the voltage value output by the power supply module 101, the voltage value on the second transistor 1046 can be reduced, thereby reducing the power consumed by the second transistor 1046.

[0167] It can be seen that based on the constant current source circuit 10 provided by the present application, VOUT is adjusted according to the resistance of the currently connected load 20 through the adjustment module, and the constant current source circuit 10 can be dynamically adjusted in power. When the power consumed by the second transistor 1046 is reduced, the heat generation of the electronic device can be reduced, and the reliability and life cycle of the electronic device can be improved. Accordingly, since the heat generation of the electronic device is reduced, when designing the electronic device, the devices used for heat dissipation can be reduced, which can reduce the design difficulty of the electronic device and reduce the size of the electronic device.

[0168] In some embodiments, the regulating module further includes a sixth resistor 111 and a seventh resistor 112;

[0169] A first end of the sixth resistor 111 is electrically connected to the base of the transistor 106 , and a second end of the sixth resistor 111 is electrically connected to the second end of the power module 101 ;

[0170] A first end of the seventh resistor 112 is grounded, and a second end of the seventh resistor 112 is electrically connected to the base of the transistor 106 .

[0171] In order to ensure that the transistor 106 is in a normal working state and reduce the probability of problems such as clipping distortion or malfunction, a reasonable bias voltage and operating current can be output to the transistor 106 through the sixth resistor 111 and the seventh resistor 112.

[0172] During the power-on phase of the constant current source circuit 10, when the feedback loop of the regulation module is not yet stable, the transistor 106 is in a saturated state. At this time, the emitter voltage and the collector voltage of the transistor 106 are approximately equal, which can be expressed as VE≈VC. The resistance values of the fourth resistor 109, the fifth resistor 110, the sixth resistor 111, and the seventh resistor 112, together with the voltage value of the voltage output from the power module 101 to the constant current module 104, and the voltage value of the voltage output from the first terminal of the power module 101 to the fifth resistor, satisfy the following formula (1):

[0173]

[0174] Among them, VOUTmin represents the minimum voltage value of the voltage output by the power module 101 to the constant current module 104; R4 represents the resistance value of the fourth resistor 109; R5 represents the resistance value of the fifth resistor 110; R6 represents the resistance value of the sixth resistor 111; R7 represents the resistance value of the seventh resistor 112; VFB represents the voltage value of the voltage output from the first end of the power module 101 to the fifth resistor 110.

[0175] In some embodiments, the power module 101 includes a DC voltage drop power supply 1011 , a filter inductor 1012 , and a filter capacitor 1013 ;

[0176] A first end of the filter capacitor 1013 is grounded, and a second end of the filter capacitor 1013 is electrically connected to a first end of the filter inductor 1012 and a first end of the constant current module 104;

[0177] The second end of the filter inductor 1012 is electrically connected to the power output end of the DC voltage drop power supply 1011 ; the second end of the fifth resistor 110 is electrically connected to the constant voltage output end of the DC voltage drop power supply 1011 .

[0178] The DC-DC buck power supply 1011 may be the aforementioned DC-DC BUCK. The DC-DC buck power supply 1011 includes a constant voltage output terminal, which may be denoted as FB, for outputting a constant voltage with a voltage value of VFB.

[0179] The filter inductor 1012 and the filter capacitor 1013 form an LC filter circuit, which filters the current output from the power output end of the DC voltage drop power supply 1011. The filtered current will flow into the first end of the constant current module 104, which can filter out the interference current carried in the current output by the power supply equipment, provide a stable voltage source for the constant current module 104, and further improve the accuracy of the current flowing from the constant current source circuit 10 to the currently connected load 20.

[0180] In some embodiments, see Figure 6 , Figure 6 A schematic diagram of a constant current source circuit provided in an embodiment of the present application; Figure 6 The schematic diagram shown includes the main control module 102, power module 101, constant current module 104, feedback module 103, and regulation module 601 of the aforementioned embodiment. The regulation module 601 can also be referred to as a power regulation module; the constant current module 104 includes the aforementioned voltage setting module and voltage-to-current conversion module; and the feedback module 103 includes a signal processing module (i.e., the signal processing unit 1032 of the aforementioned embodiment) and a current sampling module (i.e., the sampling resistor 1031 of the aforementioned embodiment).

[0181] Accordingly, see Figure 7 , Figure 7 The embodiments of this application provide Figure 6 A circuit diagram corresponding to the schematic diagram shown; Figure 7 In the circuit diagram shown, the main control module 102 includes the aforementioned microprocessing unit, the data analysis unit 1021 is the aforementioned analog-to-digital conversion module; the output control unit 1022 is the aforementioned digital-to-analog conversion module, and the power supply device is the aforementioned DC voltage drop power supply 1011 as an example. It also includes the sampling resistor 1031, the signal processing unit 1032, the first operational amplifier 1041, the first transistor 1042, the first resistor 1043, the second resistor 1044, the second operational amplifier 1045, the second transistor 1046, the feedback resistor 1047, the third resistor 1048, the third operational amplifier 105, the triode 106, the diode 107, the first capacitor 108, the fourth resistor 109, the fifth resistor 110, the sixth resistor 111, the seventh resistor 112, the filter inductor 1012, and the filter capacitor 1013 described in the aforementioned embodiment, and the above-mentioned electronic components are connected according to the connection relationship described in the aforementioned embodiment.

[0182] Based on the constant current source circuit 10 provided in the embodiment of the present application, the feedback information can represent the current value of the actual current flowing from the constant current module 104 to the connected load 20. After the main control module 102 obtains the feedback information from the feedback module 103, it adjusts the control voltage output to the second end of the constant current module 104 based on the difference between the constant current value and the current value represented by the feedback information, and adjusts the control voltage output to the constant current module 104, that is, based on the difference between the current value of the actual current flowing from the constant current module 104 to the connected load 20 and the constant current value, adjusts the current flowing from the constant current module 104 to the connected load 20, so that the current value of the current output from the third end of the constant current module 104 tends to the constant current value, that is, reduces the difference between the current value of the actual current flowing through the connected load 20 and the constant current value. Thus, when different loads 20 are connected to the constant current source circuit 10, the constant current source circuit provided by the present application can make the current value flowing through the connected load 20 tend to the constant current value, that is, the actual current flowing through the connected load 20 is a constant current. Therefore, the constant current source circuit 10 provided by the present application can also be called a closed-loop controlled linear constant current source circuit.

[0183] Furthermore, when different loads 20 are connected to the constant current source circuit 10, the regulation module dynamically adjusts the voltage output by the power supply module 101 to the constant current module 104 based on the resistance of the currently connected load 20, provided that the actual current flowing through the currently connected load 20 is a constant current value. This reduces the power applied to the electronic components in the constant current module 104, thereby reducing the heat generated by the electronic components and improving the reliability and life cycle of the electronic device. Accordingly, since the heat generated by the electronic components is reduced, the number of components used for heat dissipation can be reduced when designing the electronic device, which can reduce the design difficulty of the electronic device and reduce the size of the electronic device.

[0184] The present application also provides a light source controller, comprising the constant current source circuit 10 described in any of the aforementioned embodiments. The light source controller is configured to control a light source via the included constant current source circuit 10. Specifically, the aforementioned load 20 may be a light source. For example, the brightness of the light source can be adjusted by adjusting the constant current output by the constant current source circuit 10.

[0185] Based on the light source controller provided in the present application, the included constant current source circuit 10 can make the actual current flowing through the connected light source a constant current, thereby improving the stability of the light emission of the light source.

[0186] The present application also provides a light source system, including a light source controller and a light source; the light source controller and the light source are electrically connected. The light source controller includes the constant current source circuit 10 described in any of the aforementioned embodiments. The light source controller is configured to output current to the light source via the constant current source circuit 10; the light source is configured to emit light under the current output by the light source controller.

[0187] The light source can be a point light source, or it can also be a line light source. The light source controller can control the light-emitting mode of the light source by controlling the duration and frequency of the current output to the light source. For example, the light source controller can continuously output a constant current to the light source so that the light source is always on; or the light source controller can also periodically output a constant current of a preset duration to the light source so that the light source is stroboscopically lit. The specific type of light source and the way the light source controller controls the light source can be set according to the needs of the actual scene, and this application does not limit this.

[0188] Based on the light source system provided in the present application, the constant current source circuit 10 included in the light source controller can make the actual current flowing through the connected light source a constant current, thereby improving the stability of the light emission of the light source.

[0189] In some embodiments, the constant current source circuit 10 provided in the present application may also output current to other devices, that is, the connected load 20 may be other devices, such as a PLC (Programmable Logic Controller).

[0190] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0191] Each embodiment in this specification is described in a related manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the electronic device embodiment is generally similar to the circuit embodiment, so the description is relatively simple. For related parts, refer to the partial description of the circuit embodiment.

[0192] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application are included in the scope of protection of the present application.

Claims

1. A constant current source circuit, characterized in that: The constant current source circuit includes: a power module, a main control module, a feedback module, and a constant current module; the first end of the feedback module is electrically connected to the first end of the main control module, and the second end of the feedback module is used to electrically connect one end of the load; the first end of the constant current module is electrically connected to the power module, the second end of the constant current module is electrically connected to the second end of the main control module, and the third end of the constant current module is used to electrically connect the other end of the load; The power supply module is used to supply power to the first end of the constant current module; The feedback module is configured to obtain feedback information representing the actual current value of the constant current module flowing to the connected load through the second terminal of the feedback module; and output the feedback information to the first terminal of the main control module through the first terminal of the feedback module; The constant current module is configured to convert the control voltage received by the second terminal of the constant current module into a current output by the third terminal of the constant current module; The main control module is used to adjust the control voltage output from the second end of the main control module to the second end of the constant current module based on the difference between the preset constant current value and the current value represented by the feedback information, so that the current value of the current output from the third end of the constant current module tends to the constant current value.

2. The constant current source circuit according to claim 1, characterized in that: The constant current module includes a first operational amplifier, a first transistor, a first resistor, a second resistor, a second operational amplifier, a second transistor, a feedback resistor, and a third resistor; the first end of the first resistor is grounded; The non-inverting input terminal of the first operational amplifier is electrically connected to the second terminal of the main control module, the output terminal of the first operational amplifier is electrically connected to the first terminal of the first transistor, and the inverting input terminal of the first operational amplifier is electrically connected to the second terminal of the first resistor and the second terminal of the first transistor; The third terminal of the first transistor is electrically connected to the first terminal of the second resistor and the non-inverting input terminal of the second operational amplifier; An inverting input terminal of the second operational amplifier is electrically connected to the first terminal of the feedback resistor, and an output terminal of the second operational amplifier is electrically connected to the first terminal of the second transistor; The second terminal of the second transistor is used to be electrically connected to the other end of the load; The second end of the feedback resistor is electrically connected to the first end of the third resistor and the third end of the second transistor; The power module is electrically connected to the second end of the second resistor and the second end of the third resistor.

3. The constant current source circuit according to claim 2, characterized in that: When the first transistor is an N-channel enhancement-type MOS field-effect transistor, the first terminal of the first transistor is a gate, the second terminal of the first transistor is a source, and the third terminal of the first transistor is a drain; when the first transistor is a triode, the first terminal of the first transistor is a base, the second terminal of the first transistor is an emitter, and the third terminal of the first transistor is a collector; and / or, In the case where the second transistor is a P-channel enhancement type MOS field effect transistor, the first terminal of the second transistor is a gate, the second terminal of the second transistor is a drain, and the third terminal of the second transistor is a source; In the case that the second transistor is a triode, the first end of the second transistor is a base, the second end of the second transistor is a collector, and the third end of the second transistor is an emitter.

4. The constant current source circuit according to claim 2, characterized in that: The resistance value of the second resistor is the same as the resistance value of the third resistor.

5. The constant current source circuit according to claim 1, characterized in that: The feedback module includes a sampling resistor and a signal processing unit; a first end of the signal processing unit is electrically connected to a first end of the main control module; the first end of the sampling resistor is grounded; a second end of the sampling resistor and a second end of the signal processing unit are used to electrically connect one end of the load; The signal processing unit is used to pre-process the sampling voltage value generated on the sampling resistor by the actual current flowing through the sampling resistor to obtain feedback information; Outputting the feedback information to the first end of the main control module; wherein the preprocessing includes at least one of the following: filtering the sampled voltage value; amplifying the sampled voltage value; The sampled voltage value is converted into a digital signal.

6. The constant current source circuit according to claim 5, characterized in that: The main control module is specifically configured to calculate the current value of the actual current flowing through the sampling resistor based on the feedback information; and calculate the voltage value of the control voltage to be provided to the second terminal of the constant current module by using a closed-loop control algorithm and utilizing the difference between the calculated current value and the constant current value, with the current value of the current output from the third terminal of the constant current module tending towards the constant current value. A control voltage corresponding to the calculated voltage value is output to the second end of the constant current module through the second end of the main control module.

7. The constant current source circuit according to claim 6, characterized in that: The main control module includes a data parsing unit and an output control unit; The first end of the data parsing unit is electrically connected to the first end of the signal processing unit, and the second end of the data parsing unit is electrically connected to the first end of the output control unit; The second end of the output control unit is electrically connected to the second end of the constant current module; The data analysis unit is configured to calculate the current value of the actual current flowing through the sampling resistor based on the feedback information and the resistance value of the sampling resistor when the feedback information is a digital signal; In the case where the feedback information is an analog signal, converting the feedback information into a digital signal; and calculating the current value of the actual current flowing through the sampling resistor based on the conversion result and the resistance value of the sampling resistor; The data parsing unit is further configured to calculate, by a closed-loop control algorithm, a voltage value of a control voltage to be provided to the second terminal of the constant current module using a difference between the calculated current value and the constant current value, with the current value of the current outputted from the third terminal of the constant current module tending towards the constant current value; and to send the calculated voltage value to the first terminal of the output control unit via the second terminal of the data parsing unit; The output control unit is used to output a control voltage corresponding to the received voltage value to the second end of the constant current module.

8. The constant current source circuit according to claim 5, characterized in that: The signal processing unit is further configured to: According to a preset sampling interval, a plurality of voltage values generated on the sampling resistor by the actual current flowing through the sampling resistor are collected; Calculate the average level of the collected multiple voltage values as the sampled voltage value.

9. The constant current source circuit according to any one of claims 5 to 8, characterized in that: The constant current source circuit further includes a regulating module; a first end of the regulating module is electrically connected to a first end of the power module, a second end of the regulating module is electrically connected to a second end of the power module; a third end of the regulating module is electrically connected to a third end of the constant current module; The power supply module is further configured to output a constant voltage to the first end of the regulating module through the first end of the power supply module; The regulating module is used to adjust the voltage value of the voltage at the second end of the regulating module based on the voltage value of the constant voltage received at the first end of the regulating module and the voltage value of the voltage at the third end of the regulating module, so as to adjust the voltage value of the output voltage of the second end of the power supply module.

10. The constant current source circuit according to claim 9, characterized in that: The regulating module includes: a third operational amplifier, a transistor, a diode, a first capacitor, a fourth resistor, and a fifth resistor; the first end of the first capacitor is grounded; The non-inverting input terminal of the third operational amplifier is electrically connected to the third terminal of the constant current module and the second terminal of the first capacitor, the output terminal of the third operational amplifier is electrically connected to the anode of the diode; the cathode of the diode is electrically connected to the base of the transistor; A first end of the fifth resistor is grounded, and a second end of the fifth resistor is electrically connected to the first end of the power module and the collector of the transistor; The emitter of the transistor is electrically connected to the first end of the fourth resistor and the inverting output end of the third operational amplifier; the second end of the fourth resistor is electrically connected to the second end of the power module and the first end of the constant current circuit.

11. The constant current source circuit according to claim 10, characterized in that: The regulating module further includes a sixth resistor and a seventh resistor; A first end of the sixth resistor is electrically connected to the base of the transistor, and a second end of the sixth resistor is electrically connected to the second end of the power module; A first end of the seventh resistor is grounded, and a second end of the seventh resistor is electrically connected to the base of the transistor.

12. The constant current source circuit according to claim 10, characterized in that: The power supply module includes a DC voltage drop power supply, a filter inductor, and a filter capacitor; The first end of the filter capacitor is grounded, and the second end of the filter capacitor is electrically connected to the first end of the filter inductor and the first end of the constant current module; The second end of the filter inductor is electrically connected to the power output end of the DC voltage drop power supply; the second end of the fifth resistor is electrically connected to the constant voltage output end of the DC voltage drop power supply.

13. A light source controller, characterized in that: The light source controller includes the constant current source circuit described in any one of claims 1-12.

14. A light source system, characterized in that: The light source system includes a light source controller and a light source; the light source controller and the light source are electrically connected; the light source controller includes the constant current source circuit according to any one of claims 1 to 12; The light source controller is configured to output current to the light source through the constant current source circuit; The light source is used to emit light under the drive of the output current of the light source controller.

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