A light source driving circuit and a light source system

Abstract

An embodiment of the present application provides a light source driving circuit and a light source system. The light source driving circuit includes: a series voltage reference, a constant current control module, a switching module, a sampling module, a power supply module, and a light source module; the series voltage reference is configured to output a preset reference voltage signal to the constant current control module; the sampling module is configured to convert the working current of the light source module into a first voltage signal and transmit the first voltage signal to the constant current control module; the constant current control module is configured to compare the first voltage signal with the reference voltage signal, and in the case where the voltage difference between the first voltage signal and the reference voltage signal is greater than a preset threshold, adjust the second voltage signal output by itself, so that the switching module adjusts its own conduction degree based on the second voltage signal until the voltage difference between the first voltage signal and the reference voltage signal is not greater than the preset threshold.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and particularly to a light source driving circuit and a light source system. Background Art

[0002] In current detection and analysis instrument systems, a circuit structure as shown in Figure 1 is usually adopted to drive a deuterium lamp to ensure that the light source brightness remains stable after the deuterium lamp is lit, that is, to ensure that the current flowing through the anode of the deuterium lamp is stable.

[0003] Figure 1 The shown deuterium lamp driving circuit includes a deuterium lamp, a voltage source, a reference voltage source, a constant current control module, a sampling resistor, and a switching tube. The voltage source is used to generate a suitable DC voltage to provide power for the anode of the deuterium lamp. The sampling resistor is used to convert the current flowing through the deuterium lamp into a sampling voltage. The reference voltage source is used to provide a stable reference voltage for the constant current control module. This reference voltage is the given value of the magnitude of the current flowing through the deuterium lamp. The constant current control module is used to output a control signal based on the sampling voltage and the reference voltage and act on the switching tube. The switching tube is used to adjust the magnitude of the current flowing through the deuterium lamp based on the output of the constant current control module.

[0004] However Figure 1 in the shown deuterium lamp driving circuit, a shunt voltage regulator type voltage reference is used as the reference voltage source. The shunt voltage regulator type voltage reference has poor stability, which may lead to poor stability of the deuterium lamp driving circuit, and the light source brightness after the deuterium lamp is lit cannot be kept stable. Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a light source driving circuit and a light source system to improve the stability of the light source driving circuit. The specific technical solutions are as follows:

[0006] In a first aspect, the embodiments of this application provide a light source driving circuit, and the circuit includes:

[0007] a series voltage reference, a constant current control module, a switching module, a sampling module, a power supply module, and a light source module;

[0008] The input end of the series voltage reference is connected to the power supply module, the output end of the series voltage reference is connected to the constant current control module, and the reference potential end of the series voltage reference is connected to the sampling module; the constant current control module is also respectively connected to the sampling module, the switching module, and the power supply module; the switching module, the sampling module, and the light source module are connected in series, and any one of the switching module, the sampling module, and the light source module is connected to the power supply module;

[0009] The series voltage reference is used to output a preset reference voltage signal to the constant current control module;

[0010] The sampling module is configured to convert the operating current of the light source module into a first voltage signal and transmit the first voltage signal to the constant current control module;

[0011] The constant current control module is configured to compare the first voltage signal with the reference voltage signal. When the voltage difference between the first voltage signal and the reference voltage signal is greater than a preset threshold, it adjusts the second voltage signal output by itself, so that the switching module adjusts its conduction degree based on the second voltage signal until the voltage difference between the first voltage signal and the reference voltage signal is not greater than the preset threshold.

[0012] In a possible implementation manner, the output terminal of the series voltage reference is connected to the first input terminal of the constant current control module, and the reference potential terminal of the series voltage reference is respectively connected to the second terminal of the sampling module and the light source module; the second input terminal of the constant current control module is respectively connected to the first terminal of the sampling module and the second terminal of the switching module, the output terminal of the constant current control module is connected to the control terminal of the switching module, and the first terminal of the switching module is connected to the power supply module; the positive power supply terminal of the constant current control module is connected to the power supply module.

[0013] In a possible implementation manner, the power supply module includes a DC voltage source and an isolated power supply;

[0014] The positive input terminal of the isolated power supply is connected to the power supply terminal, and the positive output terminal of the isolated power supply is respectively connected to the positive power supply terminal of the constant current control module and the input terminal of the series voltage reference;

[0015] The DC voltage source is respectively connected to the first terminal of the switching module and the power supply terminal;

[0016] The isolated power supply is configured to supply power to the constant current control module and the series voltage reference respectively;

[0017] The DC voltage source is configured to supply power to the light source module.

[0018] In a possible implementation manner, the power supply module includes a DC voltage source;

[0019] The DC voltage source is respectively connected to the first terminal of the switching module, the positive power supply terminal of the constant current control module, the input terminal of the series voltage reference, and the power supply terminal;

[0020] The DC voltage source is configured to supply power to the constant current control module, the series voltage reference, and the light source module respectively.

[0021] In a possible implementation, the constant current control module includes a first amplifier, a first resistor, and a first capacitor;

[0022] The non-inverting input terminal of the first amplifier is connected to the output terminal of the series voltage reference. The inverting input terminal of the first amplifier is respectively connected to the second terminal of the first capacitor and the second terminal of the first resistor. The output terminal of the first amplifier is respectively connected to the first terminal of the first capacitor and the control terminal of the switching module. The positive power supply terminal of the first amplifier is connected to the power supply module;

[0023] The first terminal of the first resistor is respectively connected to the first terminal of the sampling module and the second terminal of the switching module.

[0024] In a possible implementation, the sampling module includes a second resistor;

[0025] The first terminal of the second resistor is respectively connected to the second terminal of the switching module and the second input terminal of the constant current control module. The second terminal of the second resistor is respectively connected to the light source module and the reference potential terminal of the series voltage reference.

[0026] In a possible implementation, the switching module includes an N-type switching transistor;

[0027] The control terminal of the N-type switching transistor is connected to the output terminal of the constant current control module. The first terminal of the N-type switching transistor is connected to the power supply module. The second terminal of the N-type switching transistor is respectively connected to the second input terminal of the constant current control module and the first terminal of the sampling module.

[0028] In a possible implementation, the negative power supply terminal of the first amplifier is respectively connected to the reference potential terminal of the series voltage reference, the second terminal of the sampling module, and the light source module.

[0029] In a possible implementation, the negative input terminal of the isolated power supply is grounded; the negative output terminal of the isolated power supply is respectively connected to the reference potential terminal of the series voltage reference, the second terminal of the sampling module, and the light source module.

[0030] In a possible implementation, the power supply mode of the power supply terminal is a DC power supply mode.

[0031] In a second aspect, an embodiment of the present application provides a light source system, and the light source system includes the light source driving circuit described in any one of the first aspects above.

[0032] Advantageous effects of the embodiments of the present application:

[0033] A light source driving circuit and a light source system provided by an embodiment of the present application. The light source driving circuit includes: a series voltage reference, a constant current control module, a switching module, a sampling module, a power supply module, and a light source module; the input end of the series voltage reference is connected to the power supply module, the output end of the series voltage reference is connected to the constant current control module, and the reference potential end of the series voltage reference is connected to the sampling module; the constant current control module is further connected to the sampling module, the switching module, and the power supply module respectively; the switching module, the sampling module, and the light source module are connected in series, and any one of the switching module, the sampling module, and the light source module is connected to the power supply module; the series voltage reference is used to output a preset reference voltage signal to the constant current control module; the sampling module is used to convert the working current of the light source module into a first voltage signal and transmit the first voltage signal to the constant current control module; the constant current control module is used to compare the first voltage signal with the reference voltage signal, and when the voltage difference between the first voltage signal and the reference voltage signal is greater than a preset threshold, adjust the second voltage signal output by itself, so that the switching module adjusts its own conduction degree based on the second voltage signal until the voltage difference between the first voltage signal and the reference voltage signal is not greater than the preset threshold. By using a series voltage reference as the reference voltage source (the stability of the series voltage reference is higher than that of the parallel voltage reference), connecting the input end of the series voltage reference to the power supply module, connecting the output end of the series voltage reference to the constant current control module, and connecting the reference potential end of the series voltage reference to the sampling module, the stability of the light source driving circuit is improved, so that the light source brightness remains highly stable.

[0034] Of course, it is not necessary for any product or method implementing the present application to achieve all the above advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application, and those of ordinary skill in the art can also obtain other embodiments based on these drawings.

[0036] Figure 1 It is a schematic structural diagram of a deuterium lamp driving circuit in the related art;

[0037] Figure 2 It is a schematic structural diagram of the first light source driving circuit provided by an embodiment of the present application;

[0038] Figure 3 It is a schematic structural diagram of the second light source driving circuit provided by an embodiment of the present application;

[0039] Figure 4The third structural schematic diagram of the light source driving circuit provided by the embodiment of the present application;

[0040] Figure 5 The fourth structural schematic diagram of the light source driving circuit provided by the embodiment of the present application;

[0041] Figure 6 A structural schematic diagram of the light source system provided by the embodiment of the present application. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art based on the present application belong to the scope of protection of the present application.

[0043] In the current detection and analysis instrument system, usually, a circuit structure as Figure 1 shown is used to drive the deuterium lamp to ensure that the light source brightness remains stable after the deuterium lamp is lit, that is, to ensure that the current flowing through the anode of the deuterium lamp is stable.

[0044] Figure 1 The deuterium lamp driving circuit shown includes a deuterium lamp, a voltage source, a reference voltage source, a constant current control module, a sampling resistor, and a switching tube. The voltage source is used to generate a suitable DC voltage to provide power for the anode of the deuterium lamp. The sampling resistor is used to convert the current flowing through the deuterium lamp into a sampling voltage. The reference voltage source is used to provide a stable reference voltage for the constant current control module. This reference voltage is the given value of the magnitude of the current flowing through the deuterium lamp. The constant current control module is used to output a control signal based on the sampling voltage and the reference voltage and act on the switching tube. The switching tube is used to adjust the magnitude of the current flowing through the deuterium lamp based on the output of the constant current control module.

[0045] Among them, when the deuterium lamp is normally lit, the current flows out from the higher potential end of the voltage source, passes through the sampling resistor and the switching tube, and enters the anode of the deuterium lamp; the power supply provides direct current, and the negative power supply terminal of the power supply, the lower potential end of the voltage source, and one end of the cathode of the deuterium lamp are at the same potential (grounded GND); the power supply for the reference voltage source and the constant current control module is provided by the voltage source through an electrical connection; when the deuterium lamp is normally lit, the end with a higher potential of the sampling resistor is at the same potential as the end with a higher potential of the reference voltage source.

[0046] However Figure 1In the shown deuterium lamp driving circuit, a shunt voltage regulator type voltage reference is used as the reference voltage source (it has two ports, a positive terminal and a negative terminal. The positive terminal is respectively connected to the voltage source and the sampling resistor, and the negative terminal is respectively connected to the constant current control module and the ground). The stability of the shunt voltage regulator type voltage reference is poor, which may lead to poor stability of the deuterium lamp driving circuit, and the light source brightness after the deuterium lamp is lit cannot be kept stable.

[0047] In addition, Figure 1 In the shown deuterium lamp driving circuit, the reference voltage source, the constant current control module, and the deuterium lamp are all powered by the voltage source. The power supply current loop of the reference voltage source and the constant current control module is likely to affect the stability of the anode current of the deuterium lamp.

[0048] The switching tube can only use a P-type switching tube with poor performance and difficult to obtain (such as a PNP triode, a P-type field effect transistor PMOS tube, etc.), which affects the overall performance of the deuterium lamp driving circuit.

[0049] In order to improve at least one of the above problems, an embodiment of the present application provides a light source driving circuit and a light source system.

[0050] Next, the light source driving circuit 1 provided by the embodiment of the present application will be described in detail. Refer to Figure 2 , which is the first structural schematic diagram of the light source driving circuit 1 provided by the embodiment of the present application. The light source driving circuit 1 includes:

[0051] A series voltage reference 11, a constant current control module 12, a switching module 13, a sampling module 14, a power supply module 15, and a light source module 16;

[0052] The input end of the series voltage reference 11 is connected to the power supply module 15, the output end of the series voltage reference 11 is connected to the first input end of the constant current control module 12, and the reference potential end of the series voltage reference 11 is respectively connected to the second end of the sampling module 14 and the light source module 16; the second input end of the constant current control module 12 is respectively connected to the first end of the sampling module 14 and the second end of the switching module 13, the output end of the constant current control module 12 is connected to the control end of the switching module 13, and the first end of the switching module 13 is connected to the power supply module 15; the positive power supply end of the constant current control module 12 is connected to the power supply module 15;

[0053] The series voltage reference 11 is used to output a preset reference voltage signal to the first input end of the constant current control module 12;

[0054] The sampling module 14 is configured to convert the operating current of the light source module 16 (the current flowing through the light source module 16) into a first voltage signal and transmit the first voltage signal to the second input terminal of the constant current control module 12;

[0055] The constant current control module 12 is configured to compare the first voltage signal with the reference voltage signal. When the voltage difference between the first voltage signal and the reference voltage signal is greater than a preset threshold, the constant current control module 12 adjusts the second voltage signal at its output terminal, so that the switching module 13 adjusts its conduction degree based on the second voltage signal until the voltage difference between the first voltage signal and the reference voltage signal is not greater than the preset threshold.

[0056] The sampling module 14 converts the operating current of the light source module 16 into a voltage signal to achieve feedback on the actual operating current of the light source module 16. The sampling module 14 can be a sampling resistor or other types of current sampling devices, and the present application does not specifically limit this.

[0057] The series voltage reference 11 is configured to output a highly stable preset reference voltage signal, and the preset reference voltage signal provides an accurate current setting reference (constant current reference value) for the constant current control module 12.

[0058] The constant current control module 12 compares the sampling voltage signal of the sampling module 14 (the first voltage signal, that is, the voltage drop of the sampling module 14) with the reference voltage signal, and dynamically adjusts the conduction degree of the switching module 13 based on the voltage difference between the two, so that the operating current of the light source module 16 tends to a certain value, that is, to maintain a constant current.

[0059] In one example, if the voltage value of the reference voltage signal is 1.2V and the resistance value of the sampling resistor is 4Ω, the current value of the constant current can be calculated as 300mA.

[0060] The preset threshold can be set according to the actual situation of the circuit. In one example, the preset threshold can be 0.05V.

[0061] In one example, the preset threshold can be 0V. When the preset threshold is 0V, the constant current control module 12 is used to compare the first voltage signal with the reference voltage signal. When the voltage value of the first voltage signal is not equal to the voltage value of the reference voltage signal, it adjusts the second voltage signal at its output terminal, so that the switching module 13 adjusts its own conduction degree based on the second voltage signal until the voltage value of the first voltage signal is equal to the voltage value of the reference voltage signal. Specifically, when the first voltage signal is greater than the reference voltage signal, the constant current control module 12 will adjust the second voltage signal at its output terminal to decrease, the conduction degree of the switching module 13 will decrease, and the working current of the light source module 16 will decrease until the voltage value of the first voltage signal is equal to the voltage value of the reference voltage signal; when the first voltage signal is less than the reference voltage signal, the constant current control module 12 will adjust the second voltage signal at its output terminal to increase, the conduction degree of the switching module 13 will increase, and the working current of the light source module 16 will increase until the voltage value of the first voltage signal is equal to the voltage value of the reference voltage signal.

[0062] The series voltage reference 11 mainly includes the following units: 1. A reference voltage source, usually using a bandgap reference structure or a zener diode, for providing a highly stable reference voltage; 2. A comparison amplifier, for comparing the sampled voltage with the reference voltage, and outputting a control signal based on the difference between the sampled voltage and the reference voltage to control the voltage adjustment unit; 3. A voltage adjustment unit, composed of a power triode or a field effect transistor, dynamically adjusts its own voltage drop according to the control signal to maintain the voltage stability at the output terminal of the series voltage reference 11; 4. A sampling circuit, usually using a voltage division network composed of resistors or potentiometers, feeds back the voltage at the output terminal of the series voltage reference 11 to the comparison amplifier in proportion.

[0063] The series voltage reference 11 includes three ports, namely an input terminal, an output terminal, and a reference potential terminal. The input terminal is used to connect to the power supply module 15 to provide a working voltage for the series voltage reference 11; the output terminal is used to output a preset reference voltage signal with high precision and high stability; the reference potential terminal is used to provide a reference potential to ensure that the voltages of the input terminal and the output terminal are based on a common reference point, and at the same time form a complete current loop.

[0064] Compared with the shunt voltage regulator type voltage reference, the series voltage reference 11 has higher precision and higher stability, which can improve the accuracy and stability of the light source driving circuit 1, so that the light source brightness of the light source module 16 remains highly accurate and highly stable.

[0065] The reference potential terminal of the series voltage reference 11 is connected to the second terminal of the sampling module 14, that is, the reference potential terminal of the series voltage reference 11 and the second terminal of the sampling module 14 maintain the same potential (one end of the light source module 16). The beneficial effects brought by this are as follows: The measurement of the reference voltage signal and the sampling voltage signal (the first voltage signal) are both referenced to the same potential, which can ensure that the voltage difference between the reference voltage signal and the sampling voltage signal input to the constant current control module 12 only reflects the actual current deviation, and can improve the accuracy of current detection; Through the equipotential design, the constant current control module 12 can directly compare the reference voltage signal and the sampling voltage signal without compensating for the influence of the potential difference on the comparison result additionally, simplifying the control logic.

[0066] Figure 2 In the shown light source driving circuit 1, the power supply module 15 supplies power (provides power) to the series voltage reference 11, the light source module 16, and the constant current control module 12 respectively.

[0067] In the embodiment of the present application, by using a series voltage reference as the reference voltage source (the accuracy and stability of the series voltage reference are higher than those of the shunt voltage reference), the input terminal of the series voltage reference 11 is connected to the power supply module 15, the output terminal of the series voltage reference 11 is connected to the first input terminal of the constant current control module 12, and the reference potential terminal of the series voltage reference 11 is connected to the second terminal of the sampling module 14 and the light source module 16 respectively, improving the accuracy and stability of the light source driving circuit 1 so that the light source brightness of the light source module 16 remains highly accurate and highly stable.

[0068] In a possible implementation manner, refer to Figure 3 , the power supply module 15 includes a DC voltage source 151 and an isolated power supply 152;

[0069] The positive input terminal of the isolated power supply 152 is connected to the power supply terminal, and the positive output terminal of the isolated power supply 152 is connected to the positive power supply terminal of the constant current control module 12 and the input terminal of the series voltage reference 11 respectively;

[0070] The DC voltage source 151 is connected to the first terminal of the switch module 13 and the power supply terminal respectively;

[0071] The isolated power supply 152 is used to supply power to the constant current control module 12 and the series voltage reference 11 respectively;

[0072] The DC voltage source 151 is used to supply power to the light source module 16.

[0073] In one example, the DC voltage source 151 can be a DCDC (DC-DC converter) boost circuit that boosts the 24V DC voltage at the power supply end to the 60V - 150V DC voltage required by the light source module 16.

[0074] In one example, the isolated power supply 152 can be a low-power standard isolated power supply module that converts 24V DC to 12V DC, providing 12V DC voltage for the constant current control module 12 and the series voltage reference 11.

[0075] In the embodiment of the present application, the isolated power supply 152 supplies power to the constant current control module 12 and the series voltage reference 11 respectively, and the DC voltage source 151 supplies power to the light source module 16, separating the power supply circuits of the constant current control module 12 and the series voltage reference 11 from the power supply circuit of the light source module 16. Compared with the related art where the reference voltage source, the constant current control module, and the deuterium lamp are all powered by a voltage source, the influence of the power supply circuits of the series voltage reference 11 and the constant current control module 12 on the current stability of the light source module 16 is weakened; and since the isolated power supply 152 completely isolates its input and output terminals through a transformer and there is no direct electrical connection between the input and output terminals, using the isolated power supply 152 (in a non-electrically connected manner) to supply power to the constant current control module 12 and the series voltage reference 11 can improve the reliability, safety, anti-interference ability, and stability of the light source drive circuit 1.

[0076] In a possible implementation manner, referring to Figure 4 , the power supply module 15 includes a DC voltage source 151;

[0077] The DC voltage source 151 is respectively connected to the first end of the switch module 13, the positive power supply terminal of the constant current control module 12, the input terminal of the series voltage reference 11, and the power supply end;

[0078] The DC voltage source 151 is used to supply power to the constant current control module 12, the series voltage reference 11, and the light source module 16 respectively.

[0079] In the embodiment of the present application, using the same voltage source to supply power to the constant current control module 12, the series voltage reference 11, and the light source module 16 can simplify the circuit structure of the light source drive circuit 1 and reduce costs.

[0080] In a possible implementation manner, referring to Figure 5 , the constant current control module 12 includes a first amplifier A1, a first resistor R1, and a first capacitor C1;

[0081] The non-inverting input terminal + of the first amplifier A1 is connected to the output terminal of the series voltage reference 11. The inverting input terminal - of the first amplifier A1 is respectively connected to the second terminal of the first capacitor C1 and the second terminal of the first resistor R1. The output terminal OUT of the first amplifier A1 is respectively connected to the first terminal of the first capacitor C1 and the control terminal of the switch module 13. The positive power supply terminal VDD of the first amplifier A1 is connected to the power supply module 15;

[0082] The first terminal of the first resistor R1 is respectively connected to the first terminal of the sampling module 14 and the second terminal of the switch module 13.

[0083] The first capacitor C1 is a feedback capacitor, and the first resistor R1 is an input resistor.

[0084] In the constant current control module 12, the input first voltage signal (sampling voltage signal) generates an input current through the first resistor R1. The input current charges the first capacitor C1. The voltage of the first capacitor C1 is the difference between the voltage at the output terminal OUT of the first amplifier A1 and the voltage at the inverting input terminal -. Combining with the "virtual short" characteristic of the first amplifier A1, the relationship between the first voltage signal, the reference voltage signal, and the second voltage signal is as follows:

[0085]

[0086] where R1 represents the first resistor, C1 represents the first capacitor, t represents time, Vc(t) represents the second voltage signal, V ref (t) is the reference voltage signal, and Vs(t) represents the first voltage signal.

[0087] The constant current control module 12 is used to compare the first voltage signal with the reference voltage signal and adjust the output according to the difference. When the first voltage signal is greater than the reference voltage signal, the second voltage signal output by the constant current control module 12 linearly decreases with time, the conduction degree of the switch module 13 decreases, and the working current of the light source module 16 decreases until the voltage value of the first voltage signal is equal to the voltage value of the reference voltage signal; when the first voltage signal is less than the reference voltage signal, the second voltage signal output by the constant current control module 12 linearly increases with time, the conduction degree of the switch module 13 increases, and the working current of the light source module 16 increases until the voltage value of the first voltage signal is equal to the voltage value of the reference voltage signal.

[0088] In a possible implementation manner, refer to Figure 5 , the sampling module 14 includes a second resistor R2;

[0089] The first end of the second resistor R2 is respectively connected to the second end of the switch module 13 and the second input end of the constant current control module 12, and the second end of the second resistor R2 is respectively connected to the light source module 16 and the reference potential end of the series voltage reference 11.

[0090] The second resistor R2 is a sampling resistor. The sampling resistor uses a precision resistor to convert the working current of the light source module 16 into a voltage signal (the voltage drop of the sampling resistor), so as to accurately feedback the actual working current of the light source module 16.

[0091] The reference potential end of the series voltage reference 11 is connected to the second end of the second resistor R2, that is, the reference potential end of the series voltage reference 11 and the second end of the second resistor R2 maintain the same potential (one end of the light source module 16). The beneficial effects brought by this are as follows: The measurement of the reference voltage signal and the sampling voltage signal (the first voltage signal) are both referenced to the same potential, which can ensure that the voltage difference between the reference voltage signal and the sampling voltage signal input to the constant current control module 12 only reflects the actual current deviation, and can improve the accuracy of current detection; Through the equipotential design, the constant current control module 12 can directly compare the reference voltage signal and the sampling voltage signal without additionally compensating for the influence of the potential difference on the comparison result, simplifying the control logic.

[0092] In a possible implementation manner, see Figure 5 , the switch module 13 includes an N-type switch tube M1;

[0093] The control end of the N-type switch tube M1 is connected to the output end of the constant current control module 12, the first end of the N-type switch tube M1 is connected to the power supply module 15, and the second end of the N-type switch tube M1 is respectively connected to the second input end of the constant current control module 12 and the first end of the sampling module 14.

[0094] Compared with the P-type switch tube with poor performance in the related art, the N-type switch tube M1 with high driving ability, fast switching speed and small switching loss is adopted in the embodiment of the present application, which can improve the response speed of the switch module 13 and improve the reliability of the entire light source driving circuit 1.

[0095] The N-type switch tube M1 can be an N-type field effect transistor NMOS tube or other types of N-type switch tubes. The present application does not make specific limitations on this.

[0096] In a possible implementation manner, see Figure 5 , the negative power supply terminal VEE of the first amplifier A1 is respectively connected to the reference potential end of the series voltage reference 11, the second end of the sampling module 14 and the light source module 16.

[0097] In a possible implementation, refer to Figure 3 , the negative input terminal of the isolated power supply 152 is grounded to GND.

[0098] In a possible implementation, refer to Figure 3 , the negative output terminal of the isolated power supply 152 is respectively connected to the reference potential terminal of the series voltage reference 11, the second terminal of the sampling module 14, and the light source module 16.

[0099] In a possible implementation, the power supply mode of the power supply terminal is a DC power supply mode.

[0100] The embodiment of the present application also provides a light source system 2, refer to Figure 6 , the light source system 2 includes the light source driving circuit 1 described in any one of the above embodiments.

[0101] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0102] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the related parts can refer to the partial description of the method embodiment.

[0103] The above are only the preferred embodiments of the present application and are not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A light source driving circuit, characterized in that: The circuit comprises: Series voltage reference, constant current control module, switch module, sampling module, power module and light source module; The input end of the series voltage reference is connected to the power module, the output end of the series voltage reference is connected to the constant current control module, and the reference potential end of the series voltage reference is connected to the sampling module; the constant current control module is also connected to the sampling module, the switch module, and the power module respectively; the switch module, the sampling module, and the light source module are connected in series, and any one of the switch module, the sampling module, and the light source module is connected to the power module; The series voltage reference is used to output a preset reference voltage signal to the constant current control module; The sampling module is used to convert the working current of the light source module into a first voltage signal, and transmit the first voltage signal to the constant current control module; The constant current control module is used to compare the first voltage signal with the reference voltage signal, and when the voltage difference between the first voltage signal and the reference voltage signal is greater than a preset threshold, adjust the second voltage signal output by itself, so that the switch module adjusts its own conduction degree based on the second voltage signal until the voltage difference between the first voltage signal and the reference voltage signal is no greater than the preset threshold.

2. The circuit according to claim 1, characterized in that The output end of the series voltage reference is connected to the first input end of the constant current control module, and the reference potential end of the series voltage reference is respectively connected to the second end of the sampling module and the light source module; the second input end of the constant current control module is respectively connected to the first end of the sampling module and the second end of the switch module, the output end of the constant current control module is connected to the control end of the switch module, and the first end of the switch module is connected to the power supply module; the positive power supply end of the constant current control module is connected to the power supply module.

3. The circuit according to claim 2, characterized in that The power supply module includes a DC voltage source and an isolated power supply; The positive input terminal of the isolated power supply is connected to the power supply terminal, and the positive output terminal of the isolated power supply is respectively connected to the positive power supply terminal of the constant current control module and the input terminal of the series voltage reference; The DC voltage source is connected to the first end of the switch module and the power supply end respectively; The isolated power supply is used to supply power to the constant current control module and the series voltage reference respectively; The DC voltage source is used to supply power to the light source module.

4. The circuit according to claim 2, characterized in that The power supply module includes a DC voltage source; The DC voltage source is respectively connected to the first end of the switch module, the positive power supply end of the constant current control module, the input end of the series voltage reference, and the power supply end; The DC voltage source is used to supply power to the constant current control module, the series voltage reference and the light source module respectively.

5. The circuit according to claim 2, characterized in that The constant current control module includes a first amplifier, a first resistor, and a first capacitor; The non-inverting input terminal of the first amplifier is connected to the output terminal of the series voltage reference, the inverting input terminal of the first amplifier is respectively connected to the second terminal of the first capacitor and the second terminal of the first resistor, the output terminal of the first amplifier is respectively connected to the first terminal of the first capacitor and the control terminal of the switch module, and the positive power supply terminal of the first amplifier is connected to the power supply module; The first end of the first resistor is connected to the first end of the sampling module and the second end of the switch module respectively.

6. The circuit according to claim 2, characterized in that The sampling module includes a second resistor; The first end of the second resistor is connected to the second end of the switch module and the second input end of the constant current control module respectively, and the second end of the second resistor is connected to the light source module and the reference potential end of the series voltage reference respectively.

7. The circuit according to claim 2, characterized in that The switch module includes an N-type switch tube; The control end of the N-type switch tube is connected to the output end of the constant current control module, the first end of the N-type switch tube is connected to the power module, and the second end of the N-type switch tube is respectively connected to the second input end of the constant current control module and the first end of the sampling module.

8. The circuit according to claim 5, characterized in that The negative power supply terminal of the first amplifier is respectively connected to the reference potential terminal of the series voltage reference, the second terminal of the sampling module, and the light source module.

9. The circuit according to claim 3, characterized in that The negative input terminal of the isolated power supply is grounded; the negative output terminal of the isolated power supply is respectively connected to the reference potential terminal of the series voltage reference, the second terminal of the sampling module, and the light source module.

10. The circuit according to claim 3 or 4, characterized in that: The power supply mode of the power supply end is a direct current power supply mode.

11. A light source system, characterized in that: The light source system comprises the light source driving circuit as described in any one of claims 1 to 10.

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