CN215299773U - double-MOS tube parallel current feedback constant current driving high-power laser circuit - Google Patents
double-MOS tube parallel current feedback constant current driving high-power laser circuit Download PDFInfo
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- CN215299773U CN215299773U CN202121737969.9U CN202121737969U CN215299773U CN 215299773 U CN215299773 U CN 215299773U CN 202121737969 U CN202121737969 U CN 202121737969U CN 215299773 U CN215299773 U CN 215299773U
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Abstract
The utility model relates to a pumping laser technical field discloses two parallelly connected current feedback constant current drive high-power laser instrument circuit of MOS pipe, including constant current source drive circuit, constant current source drive circuit includes that U1B is put to fortune, MOS pipe Q3, MOS pipe Q4, negative feedback regulating circuit, state MOS pipe Q3 and MOS pipe Q4 parallelly connected, U1B normal phase input is put to fortune and outside PWM signal is received, negative feedback regulating circuit is to MOS pipe Q3, after MOS pipe Q4's source current homophase input summation operation, feedback fortune is put U1B reverse phase input. The protection function and the input signal adaptability of the circuit are optimized. The technical scheme solves the technical problem that the driving design scheme of the laser switch pumping work with the double MOS tubes connected in parallel is difficult to accurately control the current flowing through the pumping.
Description
Technical Field
The utility model relates to a pumping laser technical field, concretely relates to big power laser circuit of parallelly connected current feedback constant current drive of two MOS pipes.
Background
At present, the drive design scheme of the laser switch pumping work is mostly realized by adopting a triode or a MOSFET (metal oxide semiconductor field effect transistor), but the triode has large heat productivity and large temperature drift due to the fact that the triode is under the condition of large-current high-power output, and is not beneficial to accurate control, and the problem can be solved by the drive design scheme of the MOSFET.
The common power MOSFET has been widely used to drive a general small current pump because of its excellent characteristics of low internal resistance, high withstand voltage, large current, simple driving, etc. However, most of the pumping sources on the market at present are low-voltage and large-current driving design schemes, and the current or the dissipation power of a single MOSFET cannot meet the driving design requirements of the current pumping sources, at this time, practical parallel MOS transistors are proposed to share the large current, and the dissipation power of the single MOS transistor is reduced to meet the market requirements under the condition that the total output power is not changed.
When the switching current of a single MOS tube can not meet the requirement, the MOS tubes with very close parameter performance are selected as much as possible when the multi-tube parallel control output is adopted, so that the current flowing through each branch can be ensured to be close to the same as much as possible when the parallel shunt is used. However, the prior art has the defects that: when MOS tubes are used in parallel, if the models and parameters of the MOS tubes are not consistent, the output current curve does not tend to be constant current, so that the ID-VDS curve of each MOS tube to be connected in parallel is measured as much as possible when the MOS tubes are used in parallel, the MOS tubes with consistent and coincident curves are selected, and the implementation is time-consuming and labor-consuming. And a certain risk still exists when a plurality of MOS tubes are connected in parallel and used simultaneously, if one MOS tube has a fault, the current flowing through the branch is forced to be pressed on other branches, so that the current flowing through other branches can be over-current instantly, damage or tube explosion accidents on other branches can be caused, even damage accidents of a pump source can be caused, and the result is unreasonable.
Meanwhile, most of the existing driving MOS tube schemes adopt a PWM controlled switching power supply PFC excitation driving circuit, but the PWM excitation control output current cannot well feed back the magnitude of the output current of an output end.
In summary, the driving scheme of the single MOS transistor that is required for normal operation of the current high-current pump cannot be satisfied. The driving scheme of the parallel connection of the double MOS tubes is difficult to meet the requirement of accurate current control and has certain safety risk due to the reason of current control.
SUMMERY OF THE UTILITY MODEL
In view of the not enough of background art, the utility model provides a big power laser instrument circuit of parallelly connected current feedback constant current drive of two MOS pipes, the drive design that can solve the parallelly connected laser instrument switch pumping work of two MOS pipes is difficult to carry out the technical problem of accurate control to the electric current that flows through the pumping.
For solving the technical problem, the utility model provides a following technical scheme:
the high-power laser circuit comprises a constant current source driving circuit, wherein the constant current source driving circuit comprises an operational amplifier U1B, an MOS transistor Q3, an MOS transistor Q4 and a negative feedback adjusting circuit, the MOS transistor Q3 is connected with the MOS transistor Q4 in parallel, the positive phase input end of the operational amplifier U1B receives an external PWM signal, and the negative feedback adjusting circuit feeds back the negative phase input end of the operational amplifier U1B after the same-phase input summation operation of source currents of the MOS transistor Q3 and the MOS transistor Q4.
Preferably, the source of the MOS transistor Q3 is connected with one end of the resistor R14A, the source of the MOS transistor Q4 is connected with one end of the resistor R14B, the other ends of the resistor R14A and the resistor R14B are grounded, and the negative feedback regulating circuit acquires voltages at the upper ends of the resistors R14A and R14B. The resistors R14A and R14B are respectively connected with a group of current detection circuits, and the current detection circuits are used for detecting the current flowing through the two parallel MOS tubes in real time and are matched with an external system to protect the laser.
Specifically, the negative feedback regulating circuit comprises an operational amplifier U2, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13 and a resistor R14, an output end of the operational amplifier U2 is connected with the resistor R14, the other end of the resistor R14 is connected with an inverting input end of the operational amplifier U1B, an inverting input end of the operational amplifier U2 is grounded through the resistor R13, an output end of the operational amplifier U2 and the inverting input end are connected with the resistor R12, a positive input end of the operational amplifier U2 is grounded through the resistor R11, the resistors R9 and R10 are respectively connected with a positive input end of the operational amplifier U2, the resistors R9, R10 and R13 have the same resistance values, and the resistors R11 and R12 have the same resistance values.
Preferably, the resistor R14 is connected with a zero point trimming circuit and a loop peak value trimming circuit. The zero point fine tuning circuit is used for keeping the stability and the fidelity of the waveform under high frequency and adapting to complex control input signals. The loop peak value fine tuning circuit is used for enabling an output current waveform signal to obtain complete square angle response when a square wave signal is input, and can also modulate the rising edge and the falling edge of the output current waveform to generate an overshoot phenomenon, so that the fidelity of front and rear angles of a pulse is improved.
Preferably, the output end of the operational amplifier U1B is connected to a push-pull circuit, and the push-pull circuit is used to improve the control output capability of the gate driving signals of the MOS transistor Q3 and the MOS transistor Q4. The MOS transistor Q3 is connected with a circuit formed by connecting a diode D1 and a resistor R7A in parallel, and the cathode of the diode D1 is connected with the grid of the MOS transistor Q3; the MOS transistor Q4 is connected with a circuit formed by connecting a diode D2 and a resistor R7B in parallel, and the cathode of the diode D2 is connected with the grid of the MOS transistor Q4.
Compared with the prior art, the utility model, following beneficial effect has:
the high-power laser circuit is driven by the feedback constant current of the parallel current of the double MOS tubes, the PFC excitation control is abandoned, the push-pull circuit is adopted to improve the control output capacity of a grid drive signal, so that the output current can be suitable for the feedback circuit, meanwhile, the output current of the output end of the parallel circuit of the double MOS tubes is subjected to negative feedback regulation in a series current negative feedback control mode, the linearity and the stability of the output current of the parallel circuit of the double MOS tubes are improved, and the technical problem that the current flowing through a pump is difficult to be accurately controlled by the drive design scheme of the laser switch pumping work of the parallel circuit of the double MOS tubes is solved.
Drawings
The utility model discloses there is following figure:
fig. 1 is a functional block diagram of the present invention;
fig. 2 is a circuit diagram of the present invention.
Detailed Description
The technical solution of the present patent will be described in further detail with reference to the following embodiments.
As shown in fig. 1-2, in this embodiment:
the high-power laser circuit comprises a constant current source driving circuit, wherein the constant current source driving circuit comprises an operational amplifier U1B, an MOS transistor Q3, an MOS transistor Q4 and a negative feedback adjusting circuit, the MOS transistor Q3 is connected with the MOS transistor Q4 in parallel, the positive phase input end of the operational amplifier U1B receives an external PWM signal, and the negative feedback adjusting circuit feeds back the negative phase input end of the operational amplifier U1B after the same-phase input summation operation of source currents of the MOS transistor Q3 and the MOS transistor Q4.
The external PWM signal is generated by a D/A conversion circuit, a QCW/CW modulation signal input and a signal conditioning circuit.
The drains of the MOS transistor Q3 and the MOS transistor Q4 are connected in parallel with the negative electrode J1 of the load pump. The positive pole of the pump is connected with the positive pole of the switching power supply.
The source of the MOS transistor Q3 is connected with one end of a resistor R14A, the source of the MOS transistor Q4 is connected with one end of a resistor R14B, the other ends of the resistor R14A and the resistor R14B are grounded, and the negative feedback adjusting circuit acquires the voltage at the upper ends of the resistor R14A and the resistor R14B. The resistors R14A and R14B are respectively connected with a group of current detection circuits, and the current detection circuits are used for detecting the current flowing through the two parallel MOS tubes in real time and are matched with an external system to protect the laser.
In this example, the current detected by the current detection circuit can finally reflect the approximate current flowing through the pump, the current adopts a low-side current detection scheme, and the resistances of the resistor R15A and the resistor R16A are the same as R. R14A and R14B can not only ensure the saturation voltage drop of the MOS tube to the maximum extent, but also can be used as a measuring resistor for detecting the value of the current flowing through the MOS tube.
The negative feedback regulation circuit comprises an operational amplifier U2, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13 and a resistor R14, wherein the output end of the operational amplifier U2 is connected with the resistor R14, the other end of the resistor R14 is connected with the inverting input end of the operational amplifier U1B, and the operational amplifier U2The inverting input end is grounded through a resistor R13, the output end and the inverting input end of the operational amplifier U2 are connected with a resistor R12, the non-inverting input end of the operational amplifier U2 is grounded through a resistor R11, resistors R9 and R10 are respectively connected to the non-inverting input end of the operational amplifier U2, and the resistors R9, R10 and R13 have the same resistance value, namely R1The resistance values of the resistor R11 and the resistor R12 are the same as Rf。
The resistor R14 is connected with a zero point trimming circuit and a loop peak value trimming circuit. The zero point fine tuning circuit is used for keeping the stability and the fidelity of the waveform under high frequency and adapting to complex control input signals.
In this embodiment, the "zero point" trimming circuit includes a slide rheostat R4 and a resistor R3, wherein one end of the resistor R3 is connected to a slide piece of the slide rheostat R4, and the other end is connected to a resistor R14.
The loop peak value fine tuning circuit is used for enabling an output current waveform signal to obtain complete square angle response when a square wave signal is input, and can also modulate the rising edge and the falling edge of the output current waveform to generate an overshoot phenomenon, so that the fidelity of front and rear angles of a pulse is improved.
In this embodiment, the circuit peak trimming circuit includes a slide rheostat R6, a resistor R5, and a ceramic capacitor C2, wherein one end of the resistor R5 is connected to the resistor R14, the other end is connected to a terminal of the slide rheostat R6, one end of the ceramic capacitor C2 is connected to a slide rheostat slide sheet, and the other end is grounded, and the resistance value of the access circuit of the slide rheostat can be changed by adjusting the slide rheostat slide sheet of the slide rheostat R6.
The output end of the operational amplifier U1B is connected with a push-pull circuit, and the push-pull circuit is used for improving the control output capacity of gate drive signals of the MOS transistor Q3 and the MOS transistor Q4. The MOS transistor Q3 is connected with a circuit formed by connecting a diode D1 and a resistor R7A in parallel, and the cathode of the diode D1 is connected with the grid of the MOS transistor Q3; the MOS transistor Q4 is connected with a circuit formed by connecting a diode D2 and a resistor R7B in parallel, and the cathode of the diode D2 is connected with the grid of the MOS transistor Q4.
In this embodiment, the push-pull circuit is composed of an NPN transistor and a PNP transistor, and the base electrodes of the two transistors are connected to each other, the collector electrode of the NPN transistor is connected to the positive output of the bipolar power supply, the collector electrode of the PNP transistor is connected to the negative output of the bipolar power supply, and the emitter electrodes of the two transistors are also connected to each other.
The utility model discloses a theory of operation and use flow:
after an external PWM signal is input to the non-inverting input end of the U1B, a corresponding signal is output by the U1B and enters the input end of the push-pull circuit through the resistor R2, the drive capability of the grid electrode of the MOS transistor is enhanced by the push-pull circuit through the resistor R7A and the resistor R7B, and then the working current of the MOS transistor can be controlled only through the grid electrode voltage value of the MOS transistor. The resistor R7A and the resistor R7B are used as charging current-limiting resistors, so that the discharging speed of the Q2 is limited when the Q2 is switched on when the square wave is excited for a negative half cycle, the switching characteristic of the MOS tube is deteriorated, and in order to ensure that the resistance values of the R7A and the R7B do not influence the rapid discharging speed when the R7A and the R7B are discharged, a diode forming a discharging path is connected in parallel with the charging current-limiting resistor R7A and the resistor R7B, so that after the charging current-limiting resistor and the discharging diode are added, the safety of the MOS tube is ensured, and the rapid actions of turning on and turning off of the MOS tube are also ensured.
A negative feedback regulation circuit: the current flowing through the MOS transistor Q3 and the MOS transistor Q4 can be fed back to the inverting terminal of the operational amplifier U1B in real time. Collecting the voltage values at the upper ends of the resistors R14A and R14B can reflect the magnitude of the current value flowing through the branch, wherein VR14A is the real-time voltage value on the resistor R14A, VR14B is the real-time voltage value on the resistor R14B, the operational amplifier U2 differentially inputs the voltage values, sums the voltage values, then proportionally amplifies the voltage values and outputs the voltage values, and the output voltage value is as follows:
u2out is fed through resistor R14 to the inverting input of U1B to enable feedback to the closed loop regulation circuit.
The current detection circuit: the current used for detection can finally reflect the approximate current flowing through the pump, the current adopts a low-side current detection scheme, the voltage value at the upper end of a resistor R14A is sent to the positive phase input end of an operational amplifier U3 through a resistor R15A, the grounding end of the resistor R14A is sent to the negative phase input end of an operational amplifier U3 through a resistor R16A, the output end of the operational amplifier U3 is connected with a grounding resistor R17A in parallel, an analog voltage value Vout1 is output, the analog voltage value is sent to an external microprocessor through an external A/D conversion chip to be subjected to digital-analog conversion to obtain the current value on a resistor R14A, wherein the voltage value output by the operational amplifier U3 is:
the current detection circuit connected to the resistor R14B is similar in principle, and the output voltage value of the operational amplifier U4 is Vout 2. The external microprocessor system uses the software of the upper computer to automatically judge the current values obtained from the current detection circuit connected with the resistor R14A and the current detection circuit connected with the resistor R14B, and gives an error warning and forcibly shuts down the protection laser when the difference between the two groups of currents is overlarge.
"zero point" trimming circuit: if the modulation signal received at the non-inverting input end of the U1B is a signal from an emitter follower circuit, the reference potential of a product at the output end of the U1B operational amplifier can be shifted, the higher the working temperature of components and the higher the temperature drift voltage are, and a zero point fine adjustment circuit is connected to keep the waveform stability and the fidelity under high frequency, so that the circuit can adapt to a complex control input signal
Loop peak trimming circuit: when the transient response circuit step loading occurs in the drive circuit, the grid drive can be finely adjusted and the overshoot of the grid voltage input peak value can be finely adjusted, so that the output current waveform signal can obtain complete square angle response when the square wave signal is input, the overshoot phenomenon can also occur on the rising edge and the falling edge of the output current waveform by modulation, and the fidelity of the front and rear angles of the pulse is improved.
In light of the above, the present invention is not limited to the above embodiments, and various changes and modifications can be made by the worker without departing from the scope of the present invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (7)
1. The circuit is characterized by comprising a constant current source driving circuit, wherein the constant current source driving circuit comprises an operational amplifier U1B, an MOS tube Q3, an MOS tube Q4 and a negative feedback adjusting circuit, the MOS tube Q3 is connected with the MOS tube Q4 in parallel, a positive phase input end of the operational amplifier U1B receives an external PWM signal, and the negative feedback adjusting circuit feeds back source currents of the MOS tube Q3 and the MOS tube Q4 to a reverse phase input end of the operational amplifier U1B after in-phase input summation operation.
2. The dual-MOS tube parallel current feedback constant current drive high-power laser circuit as claimed in claim 1, wherein a source of the MOS tube Q3 is connected with one end of a resistor R14A, a source of the MOS tube Q4 is connected with one end of a resistor R14B, the other ends of the resistor R14A and the resistor R14B are grounded, and the negative feedback adjusting circuit collects voltages at the upper ends of the resistor R14A and the resistor R14B.
3. The dual MOS transistor parallel current feedback constant current drive high power laser circuit as claimed in claim 2, wherein each of the resistors R14A and R14B is connected with a set of current detection circuit.
4. The dual-MOS parallel current feedback constant current drive high-power laser circuit as claimed in claim 1, wherein the negative feedback regulator comprises an operational amplifier U2, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13 and a resistor R14, the output end of the operational amplifier U2 is connected with the resistor R14, the other end of the resistor R14 is connected to the inverting input end of the operational amplifier U1B, the inverting input end of the operational amplifier U2 is grounded through the resistor R13, the output end and the inverting input end of the operational amplifier U2 are connected with the resistor R12, the non-inverting input end of the operational amplifier U2 is grounded through the resistor R11, and the resistors R9 and R10 are respectively connected to the non-inverting input end of the operational amplifier U2.
5. The dual-MOS tube parallel current feedback constant current drive high-power laser circuit as claimed in claim 4, wherein the resistor R14 is connected with a zero point trimming circuit and a loop peak value trimming circuit.
6. The double-MOS tube parallel current feedback constant current drive high-power laser circuit as claimed in claim 1, wherein the output end of the operational amplifier U1B is connected with a push-pull circuit.
7. The dual-MOS tube parallel current feedback constant current drive high-power laser circuit as claimed in claim 1, wherein the MOS tube Q3 is connected with a circuit of a diode D1 connected with a resistor R7A in parallel, and the cathode of the diode D1 is connected with the gate of the MOS tube Q3; the MOS transistor Q4 is connected with a circuit formed by a diode D2 and a resistor R7B in parallel, and the cathode of the diode D2 is connected with the gate of the MOS transistor Q4.
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| CN202121737969.9U CN215299773U (en) | 2021-07-28 | 2021-07-28 | double-MOS tube parallel current feedback constant current driving high-power laser circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116009635A (en) * | 2023-01-04 | 2023-04-25 | 北京东方锐镭科技有限公司 | Driving circuit for voltage-controlled current output |
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- 2021-07-28 CN CN202121737969.9U patent/CN215299773U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116009635A (en) * | 2023-01-04 | 2023-04-25 | 北京东方锐镭科技有限公司 | Driving circuit for voltage-controlled current output |
| CN116009635B (en) * | 2023-01-04 | 2023-08-15 | 北京东方锐镭科技有限公司 | Driving circuit for voltage-controlled current output |
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