A Laser Diode Driving Circuit with Voltage Adaptive Regulation and an Electronic Device

Abstract

An embodiment of the present application provides a laser diode drive circuit and an electronic device with voltage adaptive regulation, which relates to the field of electronic technology and is used to solve the problem of how to improve the conversion efficiency of electrical energy into light energy in the drive circuit of a laser diode. The circuit includes: a constant voltage closed-loop control circuit, a constant current closed-loop control circuit, a boost / buck switch circuit, a DC voltage input terminal of the boost / buck switch circuit, and a laser diode; the constant voltage closed-loop control circuit is respectively connected to the boost / buck switch circuit and the laser diode; the constant voltage closed-loop control circuit is used to control the control terminal voltage of the boost / buck switch circuit; the DC voltage input terminal of the boost / buck switch circuit is connected to the boost / buck switch circuit; the boost / buck switch circuit is connected to the laser diode; the boost / buck switch circuit is used to control the voltage of the laser diode; the laser diode is connected to the constant current closed-loop control circuit; the constant current closed-loop control circuit is used to adjust the current of the laser diode.

Description

Technical Field

[0001] This application relates to the field of electronic technologies, and particularly to a laser diode drive circuit and an electronic device with voltage adaptive regulation. Background Art

[0002] A laser diode is an electronic device that uses a semiconductor PN junction to convert current into light energy and generate laser light. To enable the normal operation of the laser diode, a possible implementation is to supply power to the laser diode through a fixed voltage in the drive circuit of the laser diode. However, using the above method will cause other devices in the drive circuit to consume a large amount of electric power, resulting in a low efficiency of converting electrical energy into light energy. Therefore, how to improve the conversion efficiency of converting electrical energy into light energy in the drive circuit of the laser diode has become a technical problem to be solved currently. Summary of the Invention

[0003] In view of the above problems, the purpose of the present invention is to provide a laser diode drive circuit and an electronic device with voltage adaptive regulation to improve the conversion efficiency of converting electrical energy into light energy and save electrical energy. The specific solutions are as follows:

[0004] In a first aspect, an embodiment of the present application provides a laser diode drive circuit with voltage adaptive regulation. The circuit includes: a constant voltage closed-loop control circuit, a constant current closed-loop control circuit, a boost / buck switch circuit, a DC voltage input terminal of the boost / buck switch circuit, and a laser diode;

[0005] The constant voltage closed-loop control circuit is respectively connected to the boost / buck switch circuit and the laser diode; the constant voltage closed-loop control circuit is used to control the control terminal voltage of the boost / buck switch circuit;

[0006] The DC voltage input terminal of the boost / buck switch circuit is connected to the boost / buck switch circuit; the boost / buck switch circuit is connected to the laser diode; the boost / buck switch circuit is used to control the voltage of the laser diode;

[0007] The laser diode is connected to the constant current closed-loop control circuit; the constant current closed-loop control circuit is used to regulate the current of the laser diode.

[0008] Optionally, the constant voltage closed-loop control circuit is respectively connected to the boost / buck switch circuit and the laser diode, including:

[0009] A first end of the constant voltage closed-loop control circuit is connected to a control terminal of the boost / buck switch circuit;

[0010] The second terminal of the constant voltage closed-loop control circuit is connected to the positive electrode of the laser diode; the third terminal of the constant voltage closed-loop control circuit is connected to the negative electrode of the laser diode.

[0011] Optionally, the boost / buck switching circuit is connected to the laser diode and includes:

[0012] The DC voltage output terminal of the boost / buck switching circuit is connected to the negative electrode of the laser diode.

[0013] Optionally, the laser diode is connected to the constant current closed-loop control circuit and includes:

[0014] The positive electrode of the laser diode is connected to the constant current closed-loop control circuit.

[0015] Optionally, the constant voltage closed-loop control circuit includes: a first proportional-integral amplifier circuit, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and the set voltage input terminal of the constant voltage closed-loop control circuit;

[0016] The set voltage input terminal of the constant voltage closed-loop control circuit is connected to one end of the first resistor;

[0017] The other end of the first resistor is respectively connected to the first proportional-integral amplifier circuit and one end of the second resistor;

[0018] The other end of the second resistor is respectively connected to one end of the third resistor and the ground wire;

[0019] The other end of the third resistor is respectively connected to the first proportional-integral amplifier circuit and one end of the fourth resistor;

[0020] The fourth resistor is connected in parallel with the laser diode;

[0021] One end of the fifth resistor is connected to the first proportional-integral amplifier circuit; the other end of the fifth resistor is connected to the control terminal of the boost / buck switching circuit.

[0022] Optionally, the first proportional-integral amplifier circuit includes: a first operational amplifier, a sixth resistor, a seventh resistor, and a first capacitor;

[0023] One end of the sixth resistor is connected to the connection terminal between the first resistor and the second resistor;

[0024] The other end of the sixth resistor is respectively connected to the inverting terminal of the first operational amplifier and one end of the first capacitor;

[0025] The other end of the first capacitor is connected to one end of the seventh resistor;

[0026] The other end of the seventh resistor is connected to one end of the fifth resistor;

[0027] The output end of the first operational amplifier is connected to the connection end between the seventh resistor and the fifth resistor; the non-inverting input end of the first operational amplifier is connected to the connection end between the third resistor and the fourth resistor.

[0028] Optionally, the constant current closed-loop control circuit includes: a field effect transistor, a proportional amplification circuit, an eighth resistor, a ninth resistor, and a tenth resistor;

[0029] The drain of the field effect transistor is connected to the positive pole of the laser diode;

[0030] The gate of the field effect transistor is connected to one end of the eighth resistor; the other end of the eighth resistor is connected to the proportional amplification circuit;

[0031] One end of the ninth resistor is connected to one end of the tenth resistor; the other end of the ninth resistor is connected to the proportional amplification circuit;

[0032] The source of the field effect transistor is connected to the connection end of the ninth resistor and the tenth resistor;

[0033] The other end of the tenth resistor is grounded.

[0034] Optionally, the proportional amplification circuit includes: a second capacitor, a second operational amplifier, an eleventh resistor, and a twelfth resistor;

[0035] One end of the second capacitor is respectively connected to the other end of the eighth resistor and the output end of the second operational amplifier;

[0036] The other end of the second capacitor is respectively connected to the other end of the ninth resistor and the inverting input end of the second operational amplifier;

[0037] One end of the eleventh resistor and one end of the twelfth resistor are connected;

[0038] The other end of the eleventh resistor is connected to the set voltage input end of the constant current closed-loop control circuit;

[0039] The other end of the twelfth resistor is grounded;

[0040] The non-inverting input end of the second operational amplifier is connected to one end of the eleventh resistor; the fourth pin of the second operational amplifier is grounded; the eighth pin of the second operational amplifier is connected to the power supply.

[0041] Optionally, the field effect transistor is any one of a transistor, a field effect transistor, and an insulated gate bipolar transistor.

[0042] In a second aspect, an embodiment of the present application provides an electronic device, including any one of the above laser diode driving circuits with voltage adaptive regulation.

[0043] Compared with the prior art, the present application has the following beneficial effects:

[0044] In the present application, a constant voltage closed-loop control circuit, a constant current closed-loop control circuit, a boost / buck switching circuit, a DC voltage input terminal of the boost / buck switching circuit, and a laser diode are provided in the laser diode driving circuit. The constant voltage closed-loop control circuit is respectively connected to the boost / buck switching circuit and the laser diode. The DC voltage input terminal of the boost / buck switching circuit is connected to the boost / buck switching circuit. The boost / buck switching circuit is connected to the laser diode. The laser diode is connected to the constant current closed-loop control circuit. And the control terminal voltage of the boost / buck switching circuit is controlled by the constant voltage closed-loop control circuit. The voltage of the laser diode is controlled by the boost / buck switching circuit. The current of the laser diode is regulated by the constant current closed-loop control circuit. Thus, a dynamically variable and adjusted voltage is output to the laser diode through the boost / buck switching circuit, realizing the voltage adaptive regulation control of the laser diode driving circuit, reducing the power loss generated on other devices in the circuit, and improving the conversion efficiency of electrical energy into light energy. Description of the Drawings

[0045] 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 drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0046] Figure 1 Schematic diagram of the laser diode driving circuit for supplying power to the laser diode with a fixed voltage provided by an embodiment of the present application;

[0047] Figure 2 Schematic diagram of a laser diode driving circuit with voltage adaptive regulation provided by an embodiment of the present application;

[0048] Figure 3 Schematic diagram of the constant voltage closed-loop control circuit provided by an embodiment of the present application;

[0049] Figure 4 Schematic diagram of the first proportional integral amplification circuit provided by an embodiment of the present application;

[0050] Figure 5 Schematic diagram of the constant current closed-loop control circuit provided by an embodiment of the present application;

[0051] Figure 6Schematic diagram of the proportional amplification circuit provided by the embodiment of the present application. Detailed implementation manners

[0052] 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 belong to the scope of protection of the present application.

[0053] The terms "including" and "having" in the specification and claims of the present application and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0054] A laser diode drive circuit that supplies power to a laser diode through a fixed voltage is as Figure 1 shown. Figure 1 In the figure, the VCC DC voltage is connected to the positive electrode of the laser diode, and the negative electrode of the laser diode is connected to the drain of the field effect transistor. When a set voltage is input to the constant current control module, the constant current control module controls the change of the resistance value between the drain and source of the field effect transistor by driving the gate voltage of the field effect transistor to achieve current limiting and voltage division in the series circuit. The VCC current forms a loop through the laser diode, the field effect transistor, and the sampling resistor. The current flowing through the sampling resistor generates a voltage that is fed back to the constant current control module to form a constant current closed-loop control.

[0055] It can be seen from Figure 1 that the laser diode, the field effect transistor, and the sampling resistor are in a series relationship. When the VCC voltage is a fixed value of 5V, the conduction voltage of the laser diode is about 2V, and when the current flowing through the series loop is 1A, the voltage across the field effect transistor and the sampling resistor is 3V. According to the electric power calculation formula P = UI, the power consumed on the field effect transistor and the sampling resistor is approximately equal to 3W. When the current flowing through the series loop is 10A, the power consumed on the field effect transistor and the sampling resistor is approximately equal to 30W, and so on.

[0056] Since the VCC voltage is fixed, the electric power consumed by the field effect transistor and the sampling resistor will increase continuously with the increase of the current, resulting in a large amount of electric power consumption by the field effect transistor and the sampling resistor in the drive circuit, and the efficiency of converting electric energy into light energy is relatively low. Moreover, if the value of the sampling resistor is reduced to lower the power consumption on the sampling resistor, the power consumption on the field effect transistor will also increase accordingly, and a field effect transistor with a higher power is required to meet the current-carrying capacity of a large current. The price of a high-power field effect transistor is also higher. In addition, the waste heat generated by the electric power consumption on the field effect transistor also requires an additional heat dissipation and cooling system, which is not conducive to miniaturizing the device. To solve the above problems, the present application provides a laser diode drive circuit and an electronic device with voltage adaptive regulation, as follows.

[0057] As Figure 2 shown, the present application provides a laser diode drive circuit with voltage adaptive regulation. The circuit includes: a constant voltage closed-loop control circuit 201, a constant current closed-loop control circuit 203, a boost / buck switch circuit 202, the DC voltage input terminal Vin of the boost / buck switch circuit 202, and a laser diode D1;

[0058] The constant voltage closed-loop control circuit 201 is respectively connected to the boost / buck switch circuit 202 and the laser diode D1; the constant voltage closed-loop control circuit 201 is used to control the control terminal voltage of the boost / buck switch circuit 202;

[0059] The DC voltage input terminal Vin of the boost / buck switch circuit 202 is connected to the boost / buck switch circuit 202; the boost / buck switch circuit 202 is connected to the laser diode D1; the boost / buck switch circuit 202 is used to control the voltage of the laser diode D1;

[0060] The laser diode D1 is connected to the constant current closed-loop control circuit 203; the constant current closed-loop control circuit 203 is used to adjust the current of the laser diode D1.

[0061] Specifically, the first terminal of the constant voltage closed-loop control circuit 201 is connected to the control terminal Trim of the boost / buck switch circuit 202; the second terminal of the constant voltage closed-loop control circuit 201 is connected to the negative electrode of the laser diode D1; the third terminal of the constant voltage closed-loop control circuit 201 is connected to the positive electrode of the laser diode D1.

[0062] The DC voltage output terminal Vout of the boost / buck switch circuit 202 is connected to the positive electrode of the laser diode D1. The negative electrode of the laser diode D1 is connected to the constant current closed-loop control circuit 203. The boost / buck switch circuit 202 is specifically used to adjust the voltage input from the DC voltage input terminal Vin based on the input voltage of the control terminal Trim until the voltage of the DC voltage output terminal Vout is within the voltage range set by the set voltage input terminal Vset.

[0063] The control terminal voltage of the step-up / step-down switch circuit 202 is controlled by the constant-voltage closed-loop control circuit 201, so as to control the dynamic transformation and adjustment of the voltage output from the output terminal of the step-up / step-down switch circuit 202 to the laser diode D1, realizing the voltage adaptive regulation control of the laser diode drive circuit. Compared with supplying power to the laser diode with a fixed power supply, it can effectively reduce the power loss generated by the current on other devices in the circuit and improve the conversion efficiency of electrical energy into light energy.

[0064] As Figure 3 shown, in an optional embodiment, the constant-voltage closed-loop control circuit 201 includes: a first proportional-integral amplifier circuit 301, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and the set voltage input terminal Vset of the constant-voltage closed-loop control circuit 201;

[0065] The set voltage input terminal of the constant-voltage closed-loop control circuit 201 is connected to one end of the first resistor R1;

[0066] The other end of the first resistor R1 is respectively connected to one end of the first proportional-integral amplifier circuit 301 and one end of the second resistor R2;

[0067] The other end of the second resistor R2 is respectively connected to one end of the third resistor R3 and the ground wire;

[0068] The other end of the third resistor R3 is respectively connected to one end of the first proportional-integral amplifier circuit 301 and one end of the fourth resistor R4;

[0069] The fourth resistor R4 is connected in parallel with the laser diode D1;

[0070] One end of the fifth resistor R5 is connected to the first proportional-integral amplifier circuit 301; the other end of the fifth resistor R5 is connected to the control terminal of the step-up / step-down switch circuit 202.

[0071] When the voltage of the set voltage input terminal Vset of the constant-voltage closed-loop control circuit 201 is not set, the DC voltage output terminal Vout of the step-up / step-down switch circuit 202 has no output voltage. When there is a voltage at the set voltage input terminal Vset, the voltage is divided by the first resistor R1 and the second resistor R2 and then input to the first proportional-integral amplifier circuit 301.

[0072] As Figure 4 shown, in an optional embodiment, the first proportional-integral amplifier circuit 301 includes: a first operational amplifier U1A, a sixth resistor R6, a seventh resistor R7, and a first capacitor C1;

[0073] One end of the sixth resistor R6 is connected to the connection terminal between the first resistor R1 and the second resistor R2;

[0074] The other end of the sixth resistor R6 is respectively connected to the inverting terminal of the first operational amplifier U1A and one end of the first capacitor C1;

[0075] The other end of the first capacitor C1 is connected to one end of the seventh resistor R7;

[0076] The other end of the seventh resistor R7 is connected to one end of the fifth resistor R5;

[0077] The output terminal of the first operational amplifier U1A is connected to the connection terminal between the seventh resistor R7 and the fifth resistor R5; the non-inverting terminal of the first operational amplifier U1A is connected to the connection terminal between the third resistor R3 and the fourth resistor R4.

[0078] The first proportional-integral amplification circuit 301 is composed of the first operational amplifier U1A, the sixth resistor R6, the seventh resistor R7, and the first capacitor C1. The non-inverting terminal of the first operational amplifier U1A is pin 5, the inverting terminal is pin 6, and the output terminal is pin 7. The first operational amplifier U1A can also be composed of multiple transistors or multiple field effect transistors.

[0079] When there is a voltage at the voltage input terminal Vset, the voltage is divided by the first resistor R1 and the second resistor R2 and then input to the first proportional-integral amplification circuit 301. Since there is no output voltage at the DC voltage output terminal Vout, the non-inverting terminal of the first operational amplifier U1A is equivalent to being grounded. According to the principle that the voltages at the non-inverting terminal and the inverting terminal of the operational amplifier are equal, when the input voltage at the inverting terminal is greater than the non-inverting terminal, the voltage output by the first proportional-integral amplification circuit is close to 0 volts. After being limited by the fifth resistor R5, it is input to the control terminal Trim of the step-up / step-down switching circuit 202, and the step-up / step-down switching circuit adjusts the output voltage of the DC voltage output terminal Vout according to the input value of the control terminal Trim. The DC voltage output terminal Vout is divided by the third resistor R3 and the fourth resistor R4 and then fed back to the non-inverting terminal of the first operational amplifier U1A, so that the first proportional-integral amplification circuit 301 outputs an adjusted voltage value to the control terminal Trim according to the preset ratio amplification and integration time. The constant voltage closed-loop control circuit 201 executes the above circuit actions in a loop until the voltage output by the DC voltage output terminal Vout is stabilized within the voltage range set by the voltage input terminal Vset, thereby realizing constant voltage closed-loop control.

[0080] It should be noted that the present application can configure the proportional-integral time by setting the parameter values of the sixth resistor R6, the seventh resistor R7, and the first capacitor C1. When the parameter values of the sixth resistor R6, the seventh resistor R7, and the first capacitor C1 are preset values, it can realize the rapid adaptive adjustment of the DC voltage output terminal Vout when switching between light and heavy loads.

[0081] Such as Figure 5As shown in the figure, the constant-current closed-loop control circuit 203 includes a power transistor Q1, which can be any one of a transistor, a field-effect transistor, and an insulated gate bipolar transistor. In this application, the power transistor Q1 is taken as a field-effect transistor for subsequent description.

[0082] Specifically, the constant-current closed-loop control circuit 203 includes: a field-effect transistor Q1, a proportional amplification circuit 501, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10;

[0083] The drain of the field-effect transistor Q1 is connected to the negative electrode of the laser diode D1;

[0084] The gate of the field-effect transistor Q1 is connected to one end of the eighth resistor R8; the other end of the eighth resistor R8 is connected to the proportional amplification circuit 501;

[0085] One end of the ninth resistor R9 is connected to one end of the tenth resistor R10; the other end of the ninth resistor R9 is connected to the proportional amplification circuit 501;

[0086] The source of the field-effect transistor Q1 is connected to the connection end of the ninth resistor R9 and the tenth resistor R10;

[0087] The other end of the tenth resistor R10 is grounded.

[0088] Specifically, the tenth resistor R10 is a sampling resistor. To reduce the power consumption of the sampling resistor, the resistance value of the sampling resistor can be selected based on the actual current magnitude of the constant-current closed-loop control circuit 203. For example, the resistance value of the sampling resistor can be in the range of a few milliohms to several hundred milliohms.

[0089] Since the electric power loss generated by the field-effect transistor Q1 in this application is small, the power-carrying requirement of the field-effect transistor Q1 is reduced, making the required volume of the field-effect transistor Q1 smaller, reducing the cost, and facilitating the control of the volume and cost of the laser diode drive circuit. Moreover, since the electric power loss generated by the field-effect transistor Q1 is small, the waste heat generated by the field-effect transistor Q1 is also reduced, and the demand for heat dissipation is low. Therefore, this application does not require a heat dissipation cooling system or uses a small-volume heat dissipation cooling system, which is convenient for the miniaturized design of the laser diode drive circuit and further reduces the cost. Additionally, since the constant-current closed-loop control is a linear control method, the field-effect transistor Q1 linearly conducts and exhibits a resistive property, which can effectively block the high-frequency voltage and current ripples brought by the DC power supply of the laser diode D1, avoiding the problems that the high-frequency voltage and current ripples affect the lifespan of the laser diode D1, and the instability of the laser emitted by the laser diode D1 and the poor signal-to-noise ratio affect the stability and efficiency of laser amplification.

[0090] Such as Figure 6As shown, in an alternative embodiment, the proportional amplification circuit 501 includes: a second capacitor C2, a second operational amplifier U1B, an eleventh resistor R11, and a twelfth resistor R12;

[0091] One end of the second capacitor C2 is respectively connected to the other end of the eighth resistor R8 and the output terminal of the second operational amplifier U1B;

[0092] The other end of the second capacitor C2 is respectively connected to the other end of the ninth resistor R9 and the inverting terminal of the second operational amplifier U1B;

[0093] One end of the eleventh resistor R11 is connected to one end of the twelfth resistor R12;

[0094] The other end of the eleventh resistor R11 is connected to the set voltage input terminal Iset of the constant current closed-loop control circuit 203;

[0095] The other end of the twelfth resistor R12 is grounded;

[0096] The non-inverting terminal of the second operational amplifier U1B is connected to one end of the eleventh resistor R11; the fourth pin of the second operational amplifier U1B is grounded; the eighth pin of the second operational amplifier U1B is connected to the power supply.

[0097] Specifically, the proportional amplification circuit 501 is composed of a second capacitor C2, a second operational amplifier U1B, an eleventh resistor R11, and a twelfth resistor R12. The output terminal of the second operational amplifier U1B is pin 1, the non-inverting terminal is pin 3, and the inverting terminal is pin 2. The resistance values of the third resistor R3 and the fourth resistor R4 are greater than the resistance of the current loop formed by the laser diode D1, the field effect transistor Q1, and the tenth resistor R10. The second operational amplifier U1B can also be composed of multiple transistors or multiple field effect transistors.

[0098] The second capacitor C2 plays a role in suppressing current overshoot and oscillation during the current switching process, so that within a certain range, by changing the capacitance value of the second capacitor C2, the rise time and fall time of the switching current can be adjusted.

[0099] When the voltage at the set voltage input terminal Iset of the constant current closed-loop control circuit 203 is not set, the output voltage of the second operational amplifier U1B approaches 0 volts, the field effect transistor Q1 is turned off, and no current flows through the laser diode D1. When there is a voltage input at the set voltage input terminal Iset of the constant current closed-loop control circuit 203, the voltage is divided by the eleventh resistor R11 and the twelfth resistor R12 and then input to the non-inverting terminal of the second operational amplifier U1B. The output voltage of the output terminal of the second operational amplifier U1B drives the gate of the field effect transistor Q1 after being limited by the eighth resistor, and the current at the DC voltage output terminal Vout forms a loop through the laser diode D1, the field effect transistor Q1, and the tenth resistor. The current flowing through the tenth resistor R10 generates a voltage, which is fed back to the inverting terminal of the second operational amplifier through the ninth resistor R9 to form a constant current closed-loop control. At this time, the field effect transistor Q1 conducts linearly.

[0100] Since the resistance values of the third resistor R3 and the fourth resistor R4 are much larger than the resistance of the current loop formed by the laser diode D1, the field effect transistor Q1, and the tenth resistor R10, the voltage division of the resistance in the current loop formed by the laser diode D1, the field effect transistor Q1, and the tenth resistor R10 is much lower than the voltage division of the resistance in the current loop where the third resistor R3 and the fourth resistor R4 are located. At this time, the voltage fed back to the non-inverting terminal of the first operational amplifier U1A is the voltage at the drain of the field effect transistor Q1. The first operational amplifier U1A automatically adjusts the voltage output at the DC voltage output terminal Vout of the boost / buck switch circuit 202 according to the proportional integration time of the first capacitor C1, the sixth resistor R6, and the seventh resistor R7 and the feedback voltage to adapt to the adjustment of the current magnitude of the laser diode D1 in the constant current closed-loop control circuit 203.

[0101] Based on Figure 6 the shown voltage adaptive regulation laser diode drive circuit and the electric power calculation formula P = UI, in the series loop formed by the current passing through the laser diode D1, the field effect transistor Q1, and the tenth resistor R10 in the laser diode drive circuit provided by the present application, by reducing the terminal voltage between the drain and the source of the field effect transistor Q1, the present application can effectively reduce the electric power loss generated by the current on the field effect transistor and improve the efficiency of converting electric power into light energy.

[0102] The boost / buck switch circuit 202 with controllability is used to realize the voltage conversion from the DC voltage input terminal Vin to the DC voltage output terminal Vout, and the conversion efficiency can reach 95% - 98%. The output voltage of the DC voltage output terminal Vout is dynamically and closed-loop adjusted to supply power to the laser diode, realizing the voltage adaptive regulation of the laser diode drive control. Moreover, since the output voltage value of the DC voltage output terminal Vout supports voltage adaptive regulation, the present application supports driving multiple laser diodes in series simultaneously.

[0103] Due to the characteristic that the output voltage of the DC voltage output terminal Vout can be quickly and adaptively adjusted when switching between light and heavy loads because the switching main frequency of the boost / buck switch circuit 202 is high enough, this technical solution supports operation in the pulsed constant current mode. The output voltage of the DC voltage output terminal Vout can be set reasonably according to the voltage and current parameters of the laser diode D1, so as to adjust the device parameters in the circuit by the value of the energy storage capacitor. When a current modulation frequency signal is applied to the set voltage input terminal Iset, the pulsed constant current mode operation with a frequency of 0 - 5M can be achieved.

[0104] This application also provides an electronic device, which includes any one of the above laser diode drive circuits with voltage adaptive regulation.

[0105] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key point of each embodiment is to illustrate the differences from other embodiments. In particular, for the embodiment of the electronic device, since it is basically similar to the circuit embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the circuit embodiment. The above-described embodiment of the electronic device is only illustrative. The units and modules described as separate components may or may not be physically separated. In addition, some or all of the units and modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative work.

[0106] It should be understood that in this application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can represent: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (one) of the following" or its similar expression refers to any combination of these items, including any combination of single item (one) or plural items (ones). For example, at least one (one) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0107] The above are only the preferred embodiments of the present application and do not impose any formal restrictions on the present application. Although the present application has been disclosed above with the preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present application, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of protection of the technical solution of the present application.

Claims

1. A laser diode driving circuit with voltage adaptive regulation, characterized in that: The circuit comprises: a constant voltage closed-loop control circuit, a constant current closed-loop control circuit, a boost / buck switch circuit, a DC voltage input terminal of the boost / buck switch circuit and a laser diode; The constant voltage closed-loop control circuit is connected to the boost / buck switch circuit and the laser diode respectively; the constant voltage closed-loop control circuit is used to control the control terminal voltage of the boost / buck switch circuit; The DC voltage input terminal of the boost / buck switch circuit is connected to the boost / buck switch circuit; the boost / buck switch circuit is connected to the laser diode; the boost / buck switch circuit is used to control the voltage of the laser diode; The laser diode is connected to the constant current closed-loop control circuit; the constant current closed-loop control circuit is used to adjust the current of the laser diode; Wherein, the constant voltage closed-loop control circuit comprises: a first proportional integral amplifier circuit, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a setting voltage input terminal of the constant voltage closed-loop control circuit; A setting voltage input terminal of the constant voltage closed-loop control circuit is connected to one end of the first resistor; The other end of the first resistor is connected to one end of the first proportional integral amplifier circuit and the second resistor respectively; The other end of the second resistor is respectively connected to one end of the third resistor and the ground wire; The other end of the third resistor is connected to one end of the first proportional integral amplifier circuit and the fourth resistor respectively; The fourth resistor is connected in parallel with the laser diode; One end of the fifth resistor is connected to the first proportional integral amplifier circuit; the other end of the fifth resistor is connected to the control end of the boost / buck switch circuit; Wherein, the constant current closed-loop control circuit comprises: a field effect tube, a proportional amplifier circuit, an eighth resistor, a ninth resistor and a tenth resistor; The drain of the field effect tube is connected to the cathode of the laser diode; The gate of the field effect tube is connected to one end of the eighth resistor; the other end of the eighth resistor is connected to the proportional amplifier circuit; One end of the ninth resistor is connected to one end of the tenth resistor; the other end of the ninth resistor is connected to the proportional amplifier circuit; The source of the field effect tube is connected to the connection end of the ninth resistor and the tenth resistor; The other end of the tenth resistor is grounded; The resistance values ​​of the third resistor and the fourth resistor are much greater than the resistance of the current loop formed by the laser diode, the field effect transistor and the tenth resistor.

2. The circuit according to claim 1, characterized in that The voltage step-up / step-down switch circuit is connected to the laser diode and includes: The DC voltage output end of the voltage step-up / step-down switch circuit is connected to the positive electrode of the laser diode.

3. The circuit according to claim 1, characterized in that The first proportional integral amplifier circuit comprises: a first operational amplifier, a sixth resistor, a seventh resistor and a first capacitor; One end of the sixth resistor is connected to a connection end between the first resistor and the second resistor; The other end of the sixth resistor is connected to the inverting end of the first operational amplifier and one end of the first capacitor respectively; The other end of the first capacitor is connected to one end of the seventh resistor; The other end of the seventh resistor is connected to one end of the fifth resistor; The output terminal of the first operational amplifier is connected to the connection terminal between the seventh resistor and the fifth resistor; the in-phase terminal of the first operational amplifier is connected to the connection terminal between the third resistor and the fourth resistor.

4. The circuit according to claim 1, characterized in that The proportional amplification circuit comprises: a second capacitor, a second operational amplifier, an eleventh resistor and a twelfth resistor; One end of the second capacitor is connected to the other end of the eighth resistor and the output end of the second operational amplifier respectively; The other end of the second capacitor is connected to the other end of the ninth resistor and the inverting end of the second operational amplifier respectively; One end of the eleventh resistor is connected to one end of the twelfth resistor; The other end of the eleventh resistor is connected to the setting voltage input end of the constant current closed-loop control circuit; The other end of the twelfth resistor is grounded; The non-inverting terminal of the second operational amplifier is connected to one end of the eleventh resistor; the fourth pin of the second operational amplifier is grounded; and the eighth pin of the second operational amplifier is connected to a power supply.

5. An electronic device comprising the voltage adaptively regulated laser diode drive circuit according to any one of claims 1 to 4.

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