Disclosure of Invention
The technical problem to be solved by the invention is as follows: the constant current driving circuit and the driving method are applied to laser pumping, and the problem that a traditional pre-stage power supply circuit of a laser pumping source cannot reduce cost and guarantee response speed is solved.
In order to solve the technical problems, the invention adopts the technical scheme that:
a constant current driving circuit applied to laser pumping comprises: the device comprises a main control module, a main power module, a constant current compensation output module and a basic voltage output module;
the main control module is respectively electrically connected with the main power module and the constant current compensation output module and is used for acquiring a laser control signal sent by a preceding stage circuit, outputting a first control signal group according to the laser control signal, acquiring an average current sampling signal and a peak current sampling signal of the constant current compensation output module, and outputting a second control signal group according to the average current sampling signal and the peak current sampling signal;
the main power module is respectively electrically connected with the constant current compensation output module and the basic voltage output module and is used for acquiring an initial voltage and converting the initial voltage into an initial compensation voltage and a basic voltage according to the first control signal group;
the constant current compensation output module is connected with the basic voltage output module in series and used for acquiring the initial compensation voltage, adjusting the initial compensation voltage and the output current of the constant current compensation output module according to the second control signal group and outputting a target compensation voltage to the laser pumping source;
the basic voltage output module is used for acquiring the basic voltage and outputting the basic voltage to the laser pumping source.
Further, the main control module includes:
the first arithmetic unit is electrically connected with the constant current compensation output module and is used for acquiring the laser control signal and the average current sampling signal and acquiring an error current signal according to the laser control signal and the average current sampling signal;
the current loop unit is electrically connected with the first operation unit and is used for performing 2P2Z operation on the error current signal and outputting a target operation result;
the sawtooth wave generating unit is used for generating a sawtooth wave signal;
the second operation unit is respectively electrically connected with the current loop unit and the sawtooth wave generation unit, and is used for acquiring the sawtooth wave signal and the target operation result and acquiring a reference signal according to the sawtooth wave signal and the target operation result;
the comparison unit is electrically connected with the constant current compensation output module and the second operation unit, and is used for acquiring the peak current sampling signal and the reference signal, comparing the peak current sampling signal with the reference signal and outputting a comparison result; and
and the PWM signal generation unit is electrically connected with the comparison unit and is used for outputting the second control signal group and adjusting the duty ratio of the second control signal group according to the comparison result.
Further, the constant current compensation output module includes: the first sampling resistor, the first BUCK unit, the second BUCK unit, and the first secondary coil and the second secondary coil of the first transformer;
one end of a first secondary coil of the first transformer is connected with the first BUCK unit and the second BUCK unit respectively, one end of a second secondary coil of the first transformer is connected with the first BUCK unit and the second BUCK unit respectively, and the other end of the first secondary coil of the first transformer and the other end of the second secondary coil of the first transformer are grounded;
the main power module is respectively connected with the first secondary coil and the second secondary coil, and the main control module is respectively connected with the first BUCK unit and the second BUCK unit;
the first BUCK unit and the second BUCK unit are connected in parallel in a 90-degree staggered mode, one end of the first sampling resistor is connected with the first BUCK unit and the second BUCK unit respectively, and the other end of the first sampling resistor is grounded.
Further, the first BUCK unit includes: the circuit comprises a first current sampling mutual inductor, a first transistor, a second transistor and a first inductor;
the input of first current sampling mutual-inductor respectively with the one end of the first secondary coil of first transformer and the one end of the second secondary coil of first transformer is connected, the output of first current sampling mutual-inductor with the input of first transistor is connected, the sampling input of first current sampling mutual-inductor with host system connects, the earthing terminal ground connection of first current sampling mutual-inductor, the output of first transistor respectively with first inductance and the input of second transistor is connected, the control end of first transistor with host system connects, the output ground connection of second transistor, the control end of second transistor is connected host system.
Further, the second BUCK unit includes: the current sampling transformer comprises a second current sampling transformer, a third transistor, a fourth transistor and a second inductor;
the input end of the second current sampling mutual inductor is connected with one end of the first secondary coil and one end of the second secondary coil respectively, the output end of the second current sampling mutual inductor is connected with the input end of the third transistor, the sampling input end of the second current sampling mutual inductor is connected with the main control module, the grounding end of the second current sampling mutual inductor is grounded, the output end of the third transistor is connected with the second inductor and the input end of the fourth transistor respectively, the control end of the third transistor is connected with the main control module, the output end of the fourth transistor is grounded, and the control end of the fourth transistor is connected with the main control module.
Further, the main power module includes: a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a primary coil of the first transformer, a primary coil of the second transformer, a third inductor and a capacitor;
the input end of the fifth transistor is connected to the initial voltage, the output end of the fifth transistor is respectively connected to the input end of the sixth transistor and one end of the third inductor, and the control end of the fifth transistor is connected to the main control module;
the output end of the sixth transistor is grounded, and the control end of the sixth transistor is connected with the main control module;
the input end of the seventh transistor is connected to the initial voltage, the output end of the seventh transistor is respectively connected to the input end of the eighth transistor and one end of the capacitor, and the control end of the seventh transistor is connected to the main control module;
the output end of the eighth transistor is grounded, and the control end of the eighth transistor is connected with the main control module;
the other end of the third inductor is connected with one end of the primary coil of the first transformer and one end of the primary coil of the second transformer respectively;
and the other end of the capacitor is respectively connected with the other end of the primary coil of the first transformer and the other end of the primary coil of the second transformer.
Furthermore, the main control module is electrically connected with the basic voltage output module, and is further used for acquiring a voltage sampling signal and a current sampling signal of the basic voltage output module, and adjusting the first control signal group according to the voltage sampling signal and the current sampling signal.
A driving method applied to the constant current driving circuit of any one of the above, the driving method comprising the steps of:
acquiring an initial voltage and a laser control signal;
obtaining a first control signal group according to the laser control signal;
converting the initial voltage into an initial compensation voltage and a base voltage according to the first control signal group;
acquiring a peak current sampling signal and an average current sampling signal of a constant current compensation output module;
adjusting the initial compensation voltage according to the laser control signal, the peak current sampling signal and the average current sampling signal, and obtaining a target compensation voltage;
and outputting the target compensation voltage and the base voltage to a laser pumping source.
Further, the driving method further includes the steps of:
acquiring a voltage sampling signal and a current sampling signal of the basic voltage output module;
adjusting the first control signal group according to the voltage sampling signal and the current sampling signal.
Further, the adjusting the initial compensation voltage according to the laser control signal, the peak current sampling signal, and the average current sampling signal, and obtaining a target compensation voltage includes:
obtaining an error current signal according to the laser control signal and the average current sampling signal;
2P2Z operation is carried out on the error current signal, and an operation result is output;
providing a sawtooth wave signal, and obtaining a reference signal after superposing the operation result and the sawtooth wave signal;
comparing the reference signal with the peak current sampling signal and outputting a comparison result;
and adjusting the duty ratio of the second control signal group according to the comparison result.
The invention has the beneficial effects that: compared with the traditional power supply scheme of the laser pumping module, the circuit structure of the laser pumping module is reduced from three-level power conversion to two-level power conversion, so that the overall efficiency is correspondingly improved, and the overall size is reduced. The constant current compensation output module is low-voltage output, can adopt a low-voltage MOS tube device with lower cost, and can work at higher working frequency and higher response speed compared with a high-voltage MOS tube device adopted by the traditional scheme. In addition, the series output of the constant current compensation output module and the basic voltage output module can be compatible with laser pumping modules with different voltage requirements. The constant-current compensation output module can be subjected to multi-path expansion, and is favorable for meeting the requirements of a multi-path laser pumping module.
Detailed Description
In order to explain the technical contents, the objects and the effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.
Example one
Referring to fig. 1 to 7, a first embodiment of the present invention is:
a constant current driving circuit applied to laser pumping is connected with a laser pumping source and used for supplying power to the laser pumping source.
Referring to fig. 1, the constant current driving circuit includes: the main control module 100, the main power module 200, the constant current compensation output module 300 and the base voltage output module 400. The main control module 100 is configured to obtain a laser control signal sent by a preceding stage circuit, output a first control signal group according to the laser control signal, obtain an average current sampling signal and a peak current sampling signal of the constant current compensation output module 300, and output a second control signal group according to the average current sampling signal and the peak current sampling signal. The main power module 200 is configured to obtain an initial voltage and convert the initial voltage into an initial compensation voltage and a base voltage according to the first control signal group. The constant current compensation output module 300 is configured to obtain the initial compensation voltage, adjust the initial compensation voltage and the output current thereof according to the second control signal group, and output a target compensation voltage to the laser pumping source. The base voltage output module 400 is configured to obtain the base voltage and output the base voltage to the laser pumping source. The main control module 100 is electrically connected to the main power module 200 and the constant current compensation output module 300, the main power module 200 is electrically connected to the constant current compensation output module 300 and the basic voltage output module 400, and the constant current compensation output module 300 is connected to the basic voltage output module 400 in series.
The working principle of the constant current driving circuit applied to the laser pump in the embodiment is as follows: the main control module 100 obtains the laser control signal, and outputs a first control signal group according to the laser control signal, so that the main power module 200 converts the initial voltage into the initial compensation voltage required by the constant current compensation output module 300 and the base voltage required by the base voltage output module 400 according to the first control signal group. The main control module 100 further collects an average current sampling signal and a peak current sampling signal of the constant current compensation output module 300, and outputs a second control signal group according to the average current sampling signal and the peak current sampling signal to adjust the initial compensation voltage, so as to obtain the target compensation voltage. The constant current compensation output module 300 and the basic voltage output module 400 are connected in series, and output the target compensation voltage and the basic voltage to the laser pumping source together. The laser control signal is sent by a preceding stage circuit of a constant current driving circuit in the laser system and is a TTL level signal, and the main control module 100 finally adjusts the constant current output of the whole power supply by collecting the change of the TTL level so as to meet the requirements of the laser.
Referring to fig. 2, the pumping source is not current-output when the supply voltage is lower than V2, the current output starts when the supply voltage is higher than V2, the maximum current is output when the supply voltage reaches V1, and the required supply voltage variation is substantially quasi-linear from the current output to the maximum current output. The present embodiment is designed by using such characteristics of the laser pump source, and the constant current compensation output module 300 and the basic voltage output module 400 are arranged in series to be applied to the power supply of the pump source. Illustratively, the no-load output voltage of the constant current compensation output module 300 is 2V; the basic voltage output module 400 is a basic voltage output with a wide output voltage range, a user can correspondingly adjust the basic voltage according to laser pumping source modules of different manufacturers, the voltage of the basic voltage and the voltage of the laser pumping source modules in a no-load state are added below V2, when the laser pumping source modules need to emit light, a front-stage circuit of a constant current driving circuit in a laser can send a laser control signal (the laser control signal is a voltage signal and is generally defined as 0-2.5V and correspondingly outputs 0-25A current) with a corresponding analog quantity to the constant current compensation output module 300, the main control module 100 adjusts the output voltage of the constant current compensation output module 300 according to the change of the laser control signal, the output voltage range is 2-30V, the voltage of the basic voltage output module 400 is unchanged, so that the voltages connected in series between the two modules can also change to meet different voltages required by the laser pumping source modules when outputting different currents, and finally the output of the laser pumping source modules is realized.
It can be understood that, compared with the conventional power supply scheme of the laser pump module, the constant current driving circuit of the embodiment has a circuit structure that three-stage power conversion is reduced to two-stage power conversion, so that the overall efficiency is correspondingly improved, and the size of the whole laser pump module is reduced. The constant current compensation output module 300 is a low voltage output, and may adopt a low voltage MOS device with a lower cost, and may operate at a higher operating frequency than a high voltage MOS device adopted in a conventional scheme. In addition, the serial output of the constant current compensation output module 300 and the base voltage output module 400 can be compatible with laser pump modules with different voltage requirements. The constant current compensation output module 300 can perform multi-path expansion, which is beneficial to meeting the requirements of a multi-path laser pumping module.
Referring to fig. 3, specifically, the main control module 100 includes: the first arithmetic unit 110 is configured to obtain the laser control signal and the average current sampling signal, and obtain an error current signal according to the laser control signal and the average current sampling signal. And a current loop unit 120, configured to perform 2P2Z operation on the error current signal, and output a target operation result. And a sawtooth wave generating unit 130 for generating a sawtooth wave signal. The second operation unit 140 is configured to obtain the sawtooth wave signal and the target operation result, and obtain a reference signal according to the sawtooth wave signal and the target operation result. And a comparing unit 150, configured to obtain the peak current sampling signal and the reference signal, compare the peak current sampling signal and the reference signal, and output a comparison result. A PWM (Pulse width modulation) signal generating unit 160, configured to output the second control signal group and adjust a duty ratio of the second control signal group according to the comparison result.
The first operation unit 110 is electrically connected to the constant current compensation output module 300 and the current loop unit 120, the current loop unit 120 is electrically connected to the sawtooth wave generation unit 130, the sawtooth wave generation unit 130 is electrically connected to the second operation unit 140, the second operation unit 140 is electrically connected to the comparison unit 150, the comparison unit 150 is electrically connected to the constant current compensation output module 300, the second operation unit 140 and the PWM signal generation unit 160, and the PWM signal generation unit 160 is electrically connected to the constant current compensation output module 300.
In this embodiment, the main control module 100 adopts a control chip of a DSP chip, an ARM chip, an FPGA chip, or the like, and exemplarily, a control chip of a model STM32G474RET6 is adopted in this embodiment, wherein the control chip receives a laser control signal and an average current sampling signal, a first operation unit 110 and a second operation unit 140 inside the control chip are adders, the average current sampling signal and the laser control signal pass through the first operation unit 110 to obtain an error current signal, 2P2Z calculation is performed by using a filter architecture (filter mathematical accelerator) inside the control chip, a calculation result is converted into a current inner loop reference, and the current inner loop reference is overlapped with a sawtooth wave signal generated by the sawtooth wave generation unit 130 through the second operation unit 140 to form a reference signal with a slope compensation signal. The slope compensation is added to the present embodiment to suppress the sub-harmonic oscillation problem that occurs due to duty cycles > 50%. The reference signal and the peak current sampling signal are compared by the comparing unit 150, wherein the comparing unit 150 adopts a comparator, and the comparison result outputs the second control signal group of the target duty ratio after passing through the PWM signal generating unit 160, thereby realizing the constant current output of the target compensation voltage of the constant current compensation output module 300.
Referring to fig. 4 and 5, specifically, the constant current compensation output module 300 includes: a first sampling resistor RS1, a first BUCK unit 310, a second BUCK unit 320, and a first secondary winding T1D, a second secondary winding of the first transformer. One end of a first secondary coil T1D of the first transformer is connected to the first BUCK unit 310 and the second BUCK unit 320, one end of a second secondary coil T1C of the first transformer is connected to the first BUCK unit 310 and the second BUCK unit 320, and the other end of the first secondary coil T1D of the first transformer and the other end of the second secondary coil T1C of the first transformer are both grounded. The main power module is respectively connected to the first secondary coil and the second secondary coil, and the main control module 100 is respectively connected to the first BUCK unit 310 and the second BUCK unit 320. The first BUCK unit 310 and the second BUCK unit are connected in parallel in a 90-degree staggered mode, one end of the first sampling resistor RS1 is connected with the first BUCK unit 310 and the second BUCK unit 320 respectively, and the other end of the first sampling resistor RS1 is grounded.
It can be understood that, in order to improve the corresponding time of the constant current output, two staggered 90 ° parallel BUCK units are adopted in the embodiment, and both BUCK units are voltage reduction circuits. The working frequency of the single-path BUCK unit in the embodiment is 500Khz, and the two paths of BUCK units are staggered by 1Mhz. The increase of the working frequency of the constant current compensation output module 300 brings the increase of the bandwidth of a current control loop, and the constant current driving circuit of the compensation type laser pump realizes that the rise time of the output current required by a pumping source is controlled within 5-10us, so that the working requirement of 0-20Khz dynamic frequency of a laser can be met. If a multi-path pump source module is required, the expansion of the number of paths of the constant current compensation output module 300 can be realized, so that the constant current drive control circuit of the embodiment is compatible with the requirements of a single path and a multi-path pump source.
Optionally, the first BUCK unit 310 includes: the current sampling circuit comprises a first current sampling mutual inductor TR1, a first transistor Q1, a second transistor Q2 and a first inductor L1. The input of first current sampling mutual-inductor TR1 respectively with the one end of the first secondary coil T1D of first transformer and the one end of the second secondary coil T1C of first transformer is connected, first current sampling mutual-inductor TR 1's output with first transistor Q1's input is connected, first current sampling mutual-inductor TR 1's sampling input with host system 100 is connected, first current sampling mutual-inductor TR 1's earthing terminal, first transistor Q1's output respectively with first inductance L1 and second transistor Q2's input is connected, first transistor Q1's control end with host system 100 is connected, second transistor Q2's output earthing, second transistor Q2's control end is connected host system 100.
The second BUCK unit 320 includes: a second current sampling transformer TR2, a third transistor Q3, a fourth transistor Q4, and a second inductor L2. The input end of the second current sampling transformer TR2 is connected to one end of the first secondary coil and one end of the second secondary coil, the output end of the second current sampling transformer TR2 is connected to the input end of the third transistor Q3, the sampling input end of the second current sampling transformer TR2 is connected to the main control module 100, the ground end of the second current sampling transformer TR2 is grounded, the output end of the third transistor Q3 is connected to the input ends of the second inductor L2 and the fourth transistor Q4, the control end of the third transistor Q3 is connected to the main control module 100, the output end of the fourth transistor Q4 is grounded, and the control end of the fourth transistor Q4 is connected to the main control module 100.
As can be understood, the main control module 100 correspondingly samples peak currents of the first BUCK unit 310 and the second BUCK unit 320 through the first current sampling transformer TR1 and the second current sampling transformer TR2, respectively, generates a peak current sampling signal, and sends the peak current sampling signal to the main control module 100, and the voltage at the two ends of the first sampling resistor RS1 is subjected to differential sampling to obtain an average current of the constant current compensation output module 300, and generates an average current sampling signal. The main control module 100 adjusts the duty ratio of the second control signal group according to the peak current sampling signal and the average current sampling signal, the second control signal group includes a plurality of pulse width modulation signals for respectively and independently driving the first transistor Q1, the second transistor Q2, the third transistor Q3 and the fourth transistor Q4, it can be understood that the main control module 100 adjusts the duty ratio of the second control signal group, that is, the duty ratio of each pulse width modulation signal is respectively controlled, thereby adjusting the initial compensation voltage and the output current of the constant current compensation output module 300, and realizing the constant current output of the target compensation voltage. The transistors in the constant current compensation output module 300 are low-voltage MOS transistors, and because of small junction capacitance and small impedance, compared with high-voltage MOS transistors, the constant current compensation output module can work at a higher frequency under the same heat dissipation condition, and meanwhile, low-voltage third-generation gallium nitride MOS transistors are also mature devices, and this type of device can be preferentially adopted in this embodiment, so as to improve the stability of the constant current driving circuit. In this embodiment, the specific circuit structure of the constant current compensation output module 300 may be adjusted according to actual needs, and is not limited herein.
Referring to fig. 6, the main power module includes: a fifth transistor Q5, a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8, a primary winding T1A of the first transformer, a primary winding T2A of the second transformer, a third inductor L3, and a capacitor C1. The input end of the fifth transistor Q5 is connected to the initial voltage, the output end of the fifth transistor Q5 is connected to the input end of the sixth transistor Q6 and one end of the third inductor L3, respectively, and the control end of the fifth transistor Q5 is connected to the main control module 100. The output end of the sixth transistor Q6 is grounded, and the control end of the sixth transistor Q6 is connected to the main control module 100. The input end of the seventh transistor Q7 is connected to the initial voltage, the output end of the seventh transistor Q7 is connected to the input end of the eighth transistor Q8 and one end of the capacitor C1, respectively, and the control end of the seventh transistor Q7 is connected to the main control module 100. The output end of the eighth transistor Q8 is grounded, and the control end of the eighth transistor Q8 is connected to the main control module 100. The other end of the third inductor L3 is connected to one end of the primary winding T1A of the first transformer and one end of the primary winding T2A of the second transformer, respectively. The other end of the capacitor C1 is connected to the other end of the primary winding T1A of the first transformer and the other end of the primary winding T2A of the second transformer, respectively.
It can be understood that the fifth transistor Q5, the sixth transistor Q6, the seventh transistor Q7, the eighth transistor Q8, the primary coil T1A of the first transformer, the primary coil T2A of the second transformer, the third inductor L3, and the capacitor C1 form a full-bridge conversion topology, the initial voltage is converted into two outputs through the full-bridge conversion topology, one output is the initial compensation voltage of the constant current compensation output module 300, and the other output is the base voltage of the base voltage output module 400. The first control signal group includes pulse width modulation signals for independently driving several of the fifth transistor Q5, the sixth transistor Q6, the seventh transistor Q7, and the eighth transistor Q8, respectively.
Optionally, the main control module 100 is electrically connected to the basic voltage output module 400, and the main control module 100 is further configured to obtain a voltage sampling signal and a current sampling signal of the basic voltage output module 400, and adjust the first control signal group according to the voltage sampling signal and the current sampling signal.
As can be appreciated, the main control module 100 drives the fifth transistor Q5, the sixth transistor Q6, the seventh transistor Q7 and the eighth transistor Q8 of the main power module 200 by collecting the sampling voltage and the sampling current of the base voltage output module 400, so as to realize the regulated output of the base voltage output module 400.
Referring to fig. 7, in detail, the basic voltage output module 400 includes a second sampling resistor RS2, and a first secondary winding T2D and a second secondary winding of a second transformer. One end of a first secondary coil T2D of the second transformer is grounded, the other end of the first secondary coil T2D of the second transformer is connected with one end of a second sampling resistor RS2, one end of a second secondary coil T2C of the second transformer is connected with one end of the second sampling resistor RS2, the other end of the second secondary coil T2C of the second transformer is grounded, and the other end of the second sampling resistor RS2 is used for outputting the basic voltage. The voltage at the two ends of the second sampling resistor RS2 is subjected to differential sampling to send a current sampling signal to the main control module 100 for calculation, the base voltage is sent to the operational amplifier through the voltage dividing resistor, and the voltage sampling signal is sent to the main control module 100 for calculation after the differential sampling (a relevant circuit for voltage sampling is not shown in the drawing). In other embodiments, the specific circuit of the basic voltage output module 400 can be adjusted according to actual needs, and is not limited herein.
Referring to fig. 5, optionally, the constant current compensation output module 300 further includes a ninth transistor Q9, an input end of the ninth transistor Q9 is connected to the first BUCK unit 310 and the second BUCK unit 320, respectively, an output end of the ninth transistor Q9 is used for outputting the target compensation voltage, and a control end of the ninth transistor Q9 is connected to the main control module 100. The main control module 100 is configured to drive the ninth transistor Q9 to turn off when the constant current driving circuit is in a standby state or triggers a protection action.
Example two
Referring to fig. 8 to 11, the present embodiment provides a driving method applied to the constant current driving circuit according to the first embodiment.
Referring to fig. 8, the driving method includes the steps of:
s10, acquiring an initial voltage and a laser control signal;
before this step, an initialization operation is carried out, specifically, the main control module carries out an initialization self-checking operation to detect whether the constant current driving circuit is abnormal or not, then the main control module reads the default output voltage value of the basic voltage output module,
s20, obtaining a first control signal group according to the laser control signal;
s30, converting the initial voltage into an initial compensation voltage and a basic voltage according to the first control signal group;
s40, acquiring a peak current sampling signal and an average current sampling signal of the constant current compensation output module;
s50, adjusting the initial compensation voltage according to the laser control signal, the peak current sampling signal and the average current sampling signal, and obtaining a target compensation voltage;
wherein step S30 and step S50 may be performed in parallel.
And S60, outputting the target compensation voltage and the basic voltage to a laser pumping source.
Referring to fig. 9, optionally, the driving method further includes the steps of:
s70, acquiring a voltage sampling signal and a current sampling signal of the basic voltage output module;
and S80, adjusting the first control signal group according to the voltage sampling signal and the current sampling signal.
As can be appreciated, the constant current driving circuit monitors the voltage and current states of the basic voltage output module to realize the voltage stabilization output of the basic voltage output module by adjusting the first control signal group.
Referring to fig. 10, specifically, step S50 includes:
s51, obtaining an error current signal according to the laser control signal and the average current sampling signal;
s52, performing 2P2Z operation on the error current signal and outputting an operation result;
s53, providing a sawtooth wave signal, and obtaining a reference signal after superposing the operation result and the sawtooth wave signal;
s54, comparing the reference signal with the peak current sampling signal, and outputting a comparison result;
and S55, adjusting the duty ratio of the second control signal group according to the comparison result.
Referring to fig. 11, optionally, the constant current driving method further includes the steps of:
s90, sampling a voltage sampling signal of the constant current compensation output module;
and (3) voltage sampling process of the constant current compensation output module: differential sampling is carried out after voltage division through the first sampling resistor, and a voltage sampling signal is sent to the main control module.
S100, comparing a voltage sampling signal of the constant current compensation output module with a preset voltage threshold value, and outputting a first comparison result;
when the voltage sampling signal of the constant current compensation output module is greater than or equal to the preset voltage threshold value, the constant current compensation output module is in an overvoltage output abnormal state, otherwise, the constant current compensation output module works normally;
s110, comparing an average current sampling signal of the constant current compensation output module with the preset current threshold value, and outputting a second comparison result;
when the average current sampling signal of the constant current compensation output module is greater than or equal to a preset current threshold value, the constant current compensation output module is in an overcurrent output abnormal state, otherwise, the constant current compensation output module works normally;
and S120, protecting the constant current driving circuit when the first comparison result and/or the second comparison result are abnormal.
In this step, the constant current compensation output module is in at least one of an overcurrent output state and an overvoltage output state, and then the main control module executes protection operation of the constant current driving circuit. Illustratively, the main control module drives the main power module to be turned off and drives the ninth transistor to be turned off according to the first comparison result and/or the second comparison result.
In summary, compared with the conventional power supply scheme of the laser pump module, the constant current driving circuit and the driving method applied to the laser pump provided by the invention have the advantages that the circuit structure is reduced from three-stage power conversion to two-stage power conversion, so that the overall efficiency is correspondingly improved, and the overall size is reduced. The constant current compensation output module is low-voltage output, can adopt a low-voltage MOS tube device with lower cost, and can work at higher working frequency compared with a high-voltage MOS tube device adopted by the traditional scheme. In addition, the series output of the constant current compensation output module and the basic voltage output module can be compatible with laser pumping modules with different voltage requirements. The constant-current compensation output module can be subjected to multi-path expansion, and is favorable for meeting the requirements of a multi-path laser pumping module.
In addition, the constant current driving circuit is also provided with circuit protection, the main control module monitors the current and the voltage of the constant current compensation output module, and devices such as the main power module and the like are closed in time when abnormity occurs, so that the constant current driving circuit is protected.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent modifications made by the contents of the present specification and the drawings, or applied to the related technical fields directly or indirectly, are included in the scope of the present invention.