Laser power driver circuit and laser

Abstract

The present invention discloses a power driver circuit of a laser and a laser. The power driver circuit includes a control unit, a first power unit, a second power unit, a comparison unit, a first current detection unit, and a second current detection unit; the first current detection unit and the second current detection unit connected in parallel, the power branches of the first power unit and the second power unit connected in parallel, and the working module are connected in series in sequence, the control unit is used to control the first current flowing through the first power unit and the second current flowing through the second power unit, so as to control the total current flowing through the working module; the comparison unit is used to compare the deviation between the sum of the current flowing through the first current detection unit and the current flowing through the second current detection unit and the set current, and through the regulation of the control unit, the magnitude of the first current and the second current are made as consistent as possible. The power driver circuit can stably, accurately, and quickly control the total current flowing through the working module, and has low power consumption.

Description

Technical Field

[0001] The invention belongs to the technical field of laser control, and in particular relates to a laser power driver circuit and a laser. Background Art

[0002] In industrial control systems, power drivers are roughly divided into two categories: one is a linear driver, and the other is a pulse width modulation switch driver. Compared with the pulse width modulation switch driver, the linear driver has the advantages of smooth driving, small ripple, no electromagnetic switching noise, no need for additional smoothing filter inductors, and high bandwidth. Therefore, the power driver of the laser pump source is usually a linear driver.

[0003] The stability of the laser pump output power directly determines the stability of the final laser output power of the laser. Since the laser pump output power is proportional to the square of the current flowing through the laser pump, the current flowing through the laser pump is required to flow smoothly, with small ripples, and be continuously adjustable. Although linear drivers have advantages such as smooth current flow, small ripples, and high bandwidth, there is a problem of high power consumption of the device itself, which easily leads to high temperatures and requires an additional cooling system for cooling. Generally, the power consumption of power devices consists of two parts: (1) Most of the power consumption is lost in the on-resistance of the device, and this part of the power consumption is proportional to the square of the current; (2) The switching loss generated when the device is switched is caused by the coupling dispersion capacitance of the power device or the switching signal delay.

[0004] In a continuous fiber laser, the laser is mainly in a continuous working state, so the power consumption of the device's on-resistance is the main power consumption of the laser power device. As the laser output power increases, it is necessary to provide the laser with a corresponding current. However, as the current flowing through the power device increases, the power consumption of the laser power driver device increases, and the capacity of the cooling system needs to be increased, and the rated power of the semiconductor power driver device also needs to be increased, which greatly increases the cost of the laser. Summary of the invention

[0005] In view of the above problems, the present invention discloses a power driver circuit of a laser and a laser to overcome the above problems or at least partially solve the above problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] On one hand, the present application discloses a power driver circuit of a laser, the power driver circuit comprising a control unit and a power unit; the power driver circuit further comprises a comparison unit, a first current detection unit and a second current detection unit;

[0008] The number of the control unit is one, the power unit includes a first power unit and a second power unit, the power branch of the first power unit and the power branch of the second power unit are connected in parallel to a working module outside the circuit, the first power unit and the second power unit are connected to the control unit respectively, and the control unit is used to control a first current flowing through the first power unit and a second current flowing through the second power unit, thereby controlling the total current flowing through the working module;

[0009] The comparison unit is connected to the control unit, and the first current detection unit and the second current detection unit are connected in parallel and then connected in series with the power branch of the first power unit and the power branch of the second power unit that are connected in parallel;

[0010] The comparison unit is used to compare the deviation between the sum of the current flowing through the first current detection unit and the current flowing through the second current detection unit and the set current, and send the comparison result to the control unit;

[0011] The control unit regulates the first power unit and the second power unit according to the comparison result, so that the current magnitudes of the first current and the second current are consistent.

[0012] Further, the first power unit includes a MOS tube Q1 and a resistor R3, and the second power unit includes a MOS tube Q2 and a resistor R7;

[0013] The drain of the MOS tube Q1 and the drain of the MOS tube Q2 are connected to the working module, and the source of the MOS tube Q1 and the source of the MOS tube Q2 are connected to the first current detection unit and the second current detection unit connected in parallel; the control unit is connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2 through the resistor R3 and the resistor R7 respectively.

[0014] Furthermore, the first power unit further includes a resistor R4; the second power unit further includes a resistor R8;

[0015] The gate of the MOS tube Q1 and the gate of the MOS tube Q2 are grounded through the resistor R4 and the resistor R8 respectively;

[0016] The resistance values ​​of the resistor R4 and the resistor R8 are not less than a first preset resistance value, so that the gate voltage applied to the MOS transistor Q1 and the MOS transistor Q2 is not less than the preset voltage, and the transient driving current passing through the gate of the MOS transistor Q1 and the MOS transistor Q2 is not less than the preset current.

[0017] Further, when the resistance values ​​of the resistor R3 and the resistor R7 are both 2Ω, the first preset resistance value is 2KΩ.

[0018] Further, the control unit includes an operational amplifier U1, a resistor R1, a resistor R2, a resistor R5, a resistor R6, a capacitor C1 and a capacitor C2;

[0019] The non-inverting input terminal of the operational amplifier U1 is connected to the source of the MOS tube Q1 and the source of the MOS tube Q2 through the resistor R5, the resistor R1, the capacitor C1 and the resistor R2 in sequence, the capacitor C2 is connected in parallel across the resistor R2, the inverting input terminal of the operational amplifier U1 is grounded through the resistor R6, and the output terminal of the operational amplifier U1 is connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2 through the resistor R3 and the resistor R7 respectively.

[0020] Further, the comparison unit includes an operational amplifier U2;

[0021] The in-phase input terminal of the operational amplifier U2 is connected to the set current, the inverting input terminal of the operational amplifier U2 is connected between the resistor R2 and the capacitor C1, and the output terminal of the operational amplifier U2 is connected between the resistor R1 and the resistor R5.

[0022] Further, the first current detection unit includes a first current sampling resistor, and the second current detection unit includes a second current sampling resistor. The first current sampling resistor and the second current sampling resistor are connected in parallel, and one end of the parallel connection is connected to the source of the MOS tube Q1 and the source of the MOS tube Q2, and the other end is grounded respectively.

[0023] On the other hand, the present application discloses a laser, which is provided with a single laser diode or a plurality of laser diodes connected in series as a working module, and a power driver circuit as described in any of the above items, and the power branch of the first power unit and the power branch of the second power unit are connected in parallel to the laser diode.

[0024] The advantages and beneficial effects of the present invention are:

[0025] In the power driver circuit of the present application, the power consumption of the power driver is reduced by setting two power units in parallel, and there is no need to increase the capacity of the cooling system; in addition, the power driver circuit controls the sum of the first current flowing through the first power unit and the second current flowing through the second power unit through the control unit, thereby achieving stable, accurate and rapid control of the total current flowing through the working module so that it follows the set current; and the comparison unit compares the deviation of the sum of the first current and the second current detected by the first current detection unit and the second current detection unit with the set current, and sends the comparison result to the control unit. The control unit adjusts the first power unit and the second power unit so that the current flowing through the working module follows the set current, and the current flowing through the first power unit and the second power unit is kept consistent as much as possible, thereby ensuring the consistency and stability of the operation of the two power units and extending the service life of the power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0027] Figure 1 A schematic diagram of the connection structure of a power driver circuit in one embodiment of the present application;

[0028] Figure 2 FIG. 1 is a circuit schematic diagram of a power driver circuit in one embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0031] In one embodiment of the present application, a power driver circuit of a laser is disclosed, such as Figure 1-2 As shown, the power driver circuit includes a control unit I and a power unit. The power driver circuit also includes a comparison unit IV, a first current detection unit and a second current detection unit.

[0032] Specifically, the number of control units I is one, and the power unit includes a first power unit II and a second power unit III. The power branch of the first power unit II and the power branch of the second power unit III are connected in parallel to a working module outside the circuit, and the working module is connected to a voltage source, which provides electrical energy to the working module. The first power unit II and the second power unit III are connected to the control unit I respectively, and the control unit I is used to control a first current i1 flowing through the first power unit II and a second current i2 flowing through the second power unit III, thereby controlling the total current flowing through the working module.

[0033] The first power unit II and the second power unit III are connected in parallel. Under the premise of ensuring that the original current is provided to the working module, the current flowing through each power unit is half of the original current. When there is only one power unit in the power driver circuit, its on-resistance is R. When the power driver circuit needs to output a current of I, its power consumption is: P1 = I 2 R; When there are two parallel power units in the power driver circuit, the power consumption is: P2 = (1 / 2I) 2 R+(1 / 2I) 2 R=1 / 2I 2 R, it can be seen that P2 = 1 / 2P1. Therefore, the power consumption of the two power units connected in parallel is half of the power consumption of the original single power unit.

[0034] It can be understood that the embodiment of the present application uses only two power units in parallel, but more power units can also be used in parallel according to actual needs. It should be noted that using more power units may bring more complex results and higher device costs, which needs to be balanced according to actual needs.

[0035] The control unit I controls the first power unit II and the second power unit III, thereby controlling the first current i1 flowing through the first power unit II and the second current i2 flowing through the second power unit III, thereby controlling the total current i flowing through the working module; since the total current is the sum of the first current i1 and the second current i2, that is, i=i1+i2, the total current i can be controlled by controlling the first current i1 and the second current i2.

[0036] The comparison unit IV is connected to the control unit I. The first current detection unit and the second current detection unit are connected in parallel and then connected in series with the power branch of the first power unit II and the power branch of the second power unit III.

[0037] The comparison unit IV is used to compare the deviation between the sum of the currents detected by the first current detection unit and the second current detection unit and the set current, and send the comparison result, i.e., the error, to the control unit I.

[0038] Since the sum of the currents detected by the first current detection unit and the second current detection unit is the same as the total current i flowing through the working module (at this time, Figure 2 As shown, the current flowing through the resistor R2 and the capacitor C2 is very small and can be ignored compared to the total current i), and the comparison unit IV specifically compares the deviation between the sum of the currents flowing through the first current detection unit and the second current detection unit and the set current, and then controls the first power unit II and the second power unit III through the control unit I, so that the sum of the currents detected by the first current detection unit and the second current detection unit is close to the set current, thereby making the total current i flowing through the working module as close to the set current as possible.

[0039] The control unit I regulates the first power unit II and the second power unit III according to the comparison result of the comparison unit IV, so that the sum of the currents of the first current i1 and the second current i2 can stably, accurately and quickly track the current value of the set current, and the current magnitudes of the first current i1 and the second current i2 can be kept as consistent as possible.

[0040] Normally, the different characteristics of the two power units will result in different currents flowing through the two power units. During long-term operation, the temperature of the power unit with a relatively large current is relatively high and is easily damaged. Therefore, the control unit I adjusts the first power unit II and the second power unit III to make the currents flowing through the first power unit II and the second power unit III consistent, thereby ensuring the consistency and stability of the operation of the two power units and extending the service life of the power driver circuit.

[0041] In summary, in the power driver circuit of the present embodiment, by setting two power units in parallel, the power consumption of the power driver is reduced, and there is no need to increase the capacity of the cooling system; in addition, the power driver circuit controls the first current flowing through the first power unit and the second current flowing through the second power unit through the control unit, thereby achieving stable, accurate and rapid control of the total current flowing through the working module, so that the sum of the first current and the second current follows the set current; and the comparison unit compares the deviation between the sum of the currents detected by the first current detection unit and the second current detection unit and the set current, and sends the comparison result to the control unit. The control unit adjusts the first power unit and the second power unit to make the currents flowing through the first power unit and the second power unit consistent, thereby extending the service life of the power device.

[0042] In one embodiment, Figure 2 As shown, the first power unit II includes a MOS tube Q1 and a resistor R3, and the second power unit III includes a MOS tube Q2 and a resistor R7.

[0043] Specifically, the drain of the MOS tube Q1 and the drain of the MOS tube Q2 are connected to the working module, and the source of the MOS tube Q1 and the source of the MOS tube Q2 are connected to the first current detection unit and the second current detection unit; the control unit I is connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2 through the resistor R3 and the resistor R7 respectively.

[0044] In one embodiment, Figure 2 As shown, the first power unit II further includes a resistor R4; the second power unit III further includes a resistor R8.

[0045] The gate of the MOS transistor Q1 and the gate of the MOS transistor Q2 are grounded through the resistor R4 and the resistor R8 respectively.

[0046] The resistance values ​​of the resistor R4 and the resistor R8 are not less than the first preset resistance value, so that the gate voltage of the MOS transistor Q1 and the MOS transistor Q2 is not less than the preset voltage, and thus the transient drive current passing through the gate of the MOS transistor Q1 and the MOS transistor Q2 is not less than the preset current. The resistance values ​​of the resistor R4 and the resistor R8 are not less than the first preset resistance value, which can effectively increase the dynamic current entering the gate of the MOS transistor Q1 and the MOS transistor Q2, and thus speed up the working dynamics of the MOS transistor Q1 and the MOS transistor Q2.

[0047] Further, when the resistance values ​​of the resistor R3 and the resistor R7 are both 2Ω, the first preset resistance value is 2KΩ, that is, the resistance values ​​of the resistor R4 and the resistor R8 are not less than 2KΩ.

[0048] In one embodiment, Figure 2 As shown, the control unit I includes an operational amplifier U1, a resistor R1, a resistor R2, a resistor R5, a resistor R6, a capacitor C1 and a capacitor C2.

[0049] The non-inverting input terminal of the operational amplifier U1 is connected to the source of the MOS tube Q1 and the source of the MOS tube Q2 through the resistor R5, the resistor R1, the capacitor C1 and the resistor R2 in sequence, the capacitor C2 is connected in parallel across the resistor R2, the inverting input terminal of the operational amplifier U1 is grounded through the resistor R6, and the output terminal of the operational amplifier U1 is connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2 through the resistor R3 and the resistor R7 respectively.

[0050] The test results show that when the parameters of the components in the power driver circuit of the present embodiment are the same as those in the power driver circuit containing only one power unit, the first current i1 and the second current i2 flowing through the first power unit II and the second power unit III are not much different, within the 5% allowable range, but the total current i flowing through the working module and the first current i1 and the second current i2 all show obvious self-excited oscillation, and the amplitude of the self-excited oscillation is between 5% and 10%. When resistors R3, R7, R4, and R8 are set in the power driver circuit instead of directly connecting the gate of the MOS tube Q1 and the gate of the MOS tube Q2 together, and the resistance value of the resistor R2 is increased from 1KΩ to 10KΩ, the damping of the power driver circuit can be increased, and the self-excited oscillation of the first current i1, the second current i2 and the total current i flowing through the working module can be significantly reduced, and at this time, the first current i1 and the second current i2 are not much different.

[0051] In one embodiment, Figure 2 As shown, the comparison unit IV includes an operational amplifier U2.

[0052] Specifically, the non-inverting input terminal of the operational amplifier U2 is connected to the set current, the inverting input terminal of the operational amplifier U2 is connected between the resistor R2 and the capacitor C1, the output terminal of the operational amplifier U2 is connected between the resistor R1 and the resistor R5, and the output terminal of the operational amplifier U2 is connected to the inverting input terminal of the operational amplifier U2 through the resistor R1 and the capacitor C1, so that the resistor R1, the capacitor C1 and the operational amplifier U2 constitute a local voltage negative feedback loop, which plays a role in local stability.

[0053] In one or some embodiments, the first current detection unit includes a first current sampling resistor, and the second current detection unit includes a second current sampling resistor. Figure 2 As shown, the first current sampling resistor and the second current sampling resistor are connected in parallel, one end of which is connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2, and the other end is grounded respectively.

[0054] Of course, the first current detection unit and the second current detection unit may be other current detection devices, which are also within the protection scope of the present application.

[0055] In one embodiment of the present application, a laser is disclosed, in which a single laser diode or multiple laser diodes connected in series as a working module, and a power driver circuit as in any of the above embodiments are provided, the power branch of the first power unit and the power branch of the second power unit are connected in parallel to the laser diode, that is, the drain of the MOS tube Q1 in the first power unit and the drain of the MOS tube Q2 in the second power unit are connected in parallel to the cathode of the laser diode, and the positive pole of the voltage source is connected to the anode of the laser diode. The laser has the advantages of low power consumption and strong controllability.

[0056] The above is only a specific embodiment of the present invention. Under the above teachings of the present invention, those skilled in the art can make other improvements or modifications on the basis of the above embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of the present invention, and the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A power driver circuit for a laser, the power driver circuit comprising a control unit and a power unit; characterized in that: The power driver circuit further includes a comparison unit, a first current detection unit, and a second current detection unit; The number of the control unit is one, the power unit includes a first power unit and a second power unit, the power branch of the first power unit and the power branch of the second power unit are connected in parallel to a working module outside the circuit, the first power unit and the second power unit are connected to the control unit respectively, and the control unit is used to control a first current flowing through the first power unit and a second current flowing through the second power unit, thereby controlling the total current flowing through the working module; The comparison unit is connected to the control unit, and the first current detection unit and the second current detection unit are connected in parallel and then connected in series with the power branch of the first power unit and the power branch of the second power unit that are connected in parallel; The comparison unit is used to compare the deviation between the sum of the current flowing through the first current detection unit and the current flowing through the second current detection unit and the set current, and send the comparison result to the control unit; The control unit regulates the first power unit and the second power unit according to the comparison result, so that the current magnitudes of the first current and the second current are consistent; The first power unit includes a MOS tube Q1 and a resistor R3, and the second power unit includes a MOS tube Q2 and a resistor R7; The drain of the MOS tube Q1 and the drain of the MOS tube Q2 are connected to the working module, and the source of the MOS tube Q1 and the source of the MOS tube Q2 are connected to the first current detection unit and the second current detection unit connected in parallel; the control unit is connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2 through the resistor R3 and the resistor R7 respectively; The control unit includes an operational amplifier U1, a resistor R1, a resistor R2, a resistor R5, a resistor R6, a capacitor C1 and a capacitor C2; The non-inverting input terminal of the operational amplifier U1 is connected to the source of the MOS tube Q1 and the source of the MOS tube Q2 through the resistor R5, the resistor R1, the capacitor C1 and the resistor R2 in sequence, the capacitor C2 is connected in parallel across the resistor R2, the inverting input terminal of the operational amplifier U1 is grounded through the resistor R6, and the output terminal of the operational amplifier U1 is connected to the gate of the MOS tube Q1 and the gate of the MOS tube Q2 through the resistor R3 and the resistor R7 respectively.

2. The power driver circuit according to claim 1, characterized in that: The first power unit further includes a resistor R4; the second power unit further includes a resistor R8; The gate of the MOS tube Q1 and the gate of the MOS tube Q2 are grounded through the resistor R4 and the resistor R8 respectively; The resistance values ​​of the resistor R4 and the resistor R8 are not less than a first preset resistance value, so that the gate voltage applied to the MOS transistor Q1 and the MOS transistor Q2 is not less than the preset voltage, and the transient driving current passing through the gate of the MOS transistor Q1 and the MOS transistor Q2 is not less than the preset current.

3. The power driver circuit according to claim 2, characterized in that: When the resistance values ​​of the resistor R3 and the resistor R7 are both 2Ω, the first preset resistance value is 2KΩ.

4. The power driver circuit according to claim 1, characterized in that: The comparison unit includes an operational amplifier U2; The in-phase input terminal of the operational amplifier U2 is connected to the set current, the inverting input terminal of the operational amplifier U2 is connected between the resistor R2 and the capacitor C1, and the output terminal of the operational amplifier U2 is connected between the resistor R1 and the resistor R5.

5. The power driver circuit according to any one of claims 1 to 4, characterized in that: The first current detection unit includes a first current sampling resistor, and the second current detection unit includes a second current sampling resistor. The first current sampling resistor and the second current sampling resistor are connected in parallel, and one end of the parallel connection is connected to the source of the MOS tube Q1 and the source of the MOS tube Q2, and the other end is grounded respectively.

6. A laser, characterized in that: The laser is provided with a single laser diode or a plurality of laser diodes connected in series as a working module, and a power driver circuit as described in any one of claims 1 to 5, and the power branch of the first power unit and the power branch of the second power unit are connected in parallel to the laser diode.

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