Diode driving circuit and control method thereof

Abstract

The invention belongs to the technical field of electronic equipment, and discloses a diode driving circuit and a control method thereof, and the diode driving circuit comprises an inductor, a switching tube S1, a switching tube S2, a laser diode assembly, an input capacitor, a voltage stabilizing capacitor, a diode D1, a diode D2, a control module 1 and a control module 2. One end of the input capacitor is connected with one end of the inductor and connected with the anode of the diode D1, the other end of the input capacitor is connected to GND, the other end of the inductor is connected with the drain electrode of the switching tube S1 and the anode of the diode D2, and the cathode of the diode D1 is connected with the anode of the laser diode assembly and the cathode of the diode D2. The cathode of the laser diode assembly is connected with the drain electrode of the switch tube S2, one end of the voltage stabilizing capacitor is connected with the anode of the diode D1, and the other end of the voltage stabilizing capacitor is connected with the cathode of the diode D1. According to the invention, the voltage withstanding value of the voltage stabilizing capacitor is effectively reduced while the high frequency, quick response and large current change rate performance of the pulse laser driver are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic equipment, and in particular relates to a low-cost diode driving circuit and a control method thereof. Background Art

[0002] Pulse laser drivers are widely used in the military industry, medical technology and other fields at home and abroad, and the market demand for pulse laser drivers is also growing. With the continuous development and expansion of demand for pulse laser drivers, related products in the industry are now emerging in an endless stream. While everyone is pursuing high frequency, fast response, and high current change rate of laser diode drive, cost reduction has also become a challenge that cannot be ignored and a key factor in occupying the market.

[0003] In response to the demand for high frequency, fast response, low cost and high market competitiveness of laser diode driving, it is necessary to provide a high current change rate diode driving circuit that can achieve high frequency, fast response and low cost. Summary of the invention

[0004] In view of this, the present invention proposes a low-cost diode driving circuit and a control method thereof. While meeting the high frequency, fast response and large current change rate performance of the pulse laser driver, the withstand voltage of the voltage stabilizing capacitor is effectively reduced, thereby reducing the volume of the voltage stabilizing capacitor and achieving the purpose of reducing costs.

[0005] The present invention provides a diode driving circuit, which comprises: an inductor, a switch tube S1, a voltage stabilizing capacitor, an input capacitor, a first switch unit, a second switch unit, a control module 1, a control module 2, and a switch branch composed of a switch tube S2 and a laser diode component connected in series;

[0006] The first end of the inductor is connected to the input capacitor and the first end of the first switch unit, and the other end of the input capacitor is connected to the ground; the second end of the inductor is respectively connected to the first end of the second switch unit and the drain of the switch tube S1; the second end of the first switch unit is connected to the switch branch and connected to the second end of the second switch unit; the voltage stabilizing capacitor is connected in parallel with the first switch unit;

[0007] The control module 1 is connected to the gate of the switch tube S1;

[0008] The control module 2 is connected to the gate of the switch tube S2.

[0009] Preferably, the first switch unit is composed of a diode D1, the anode of the diode D1 serves as the first end of the first switch unit, and the cathode of the diode D1 serves as the second end of the first switch unit; the second switch unit is composed of a diode D2, the anode of the diode D2 serves as the first end of the second switch unit, and the cathode of the diode D2 serves as the second end of the second switch unit.

[0010] Preferably, the first switch unit is composed of a switch tube S3, the drain of the switch tube S3 serves as the first end of the first switch unit, and the source of the switch tube S3 serves as the second end of the first switch unit; the second switch unit is composed of a switch tube S4, the drain of the switch tube S4 serves as the first end of the second switch unit, and the source of the switch tube S4 serves as the second end of the second switch unit.

[0011] Preferably, the anode of the laser diode assembly is connected to the second end of the magnetic device, and the cathode of the laser diode assembly is connected to the drain of the switch tube S2.

[0012] Preferably, the diode driving circuit is further provided with a current sampling module 1 and a current sampling module 2. The source of the switch tube S1 is connected to the ground through the current sampling module 1, and the current sampling module 1 is used to sample the current flowing through the switch tube S1 to control the current flowing through the inductor; the source of the switch tube S2 is connected to the ground through the current sampling module 2, and the current sampling module 2 is used to sample the current flowing through the switch tube S2 to control the current flowing through the laser diode component.

[0013] The present invention also provides a control method for a diode driving circuit, comprising:

[0014] In the current cycle, the control module 1 receives the external control signal D / A1. The control module 1 generates a pulse signal according to the falling edge of the control signal D / A1 to control the switch tube S1 to turn on, so as to store energy in the inductor. After the switch tube S1 is turned on for a period of time, the switch tube S1 is controlled to turn off. When the switch tube S1 is turned off, the inductor charges the voltage-stabilizing capacitor through the loop.

[0015] Preferably, the diode driving control method further includes:

[0016] In the next cycle of the current cycle, the control module 2 receives the external control signal D / A2, and when the rising edge of the external control signal D / A2 is generated, the control module 2 controls the switch tube S2 to be turned on, so as to control the current of the laser diode component;

[0017] When the falling edge of the external control signal D / A2 is generated, the switch tube S2 is controlled to be turned off through the control module 2.

[0018] Preferably, the pulse width of the pulse signal is narrower than that of the external control signal D / A1 and the external control signal D / A2.

[0019] Preferably, the pulse signal is a pulse with a fixed duty cycle or a pulse with a variable pulse width.

[0020] Preferably, the external control signal D / A1 and the external control signal D / A2 come from the same given control signal, or come from two separate given signals.

[0021] The present invention has the following beneficial effects:

[0022] 1. The circuit topology and control logic of the present invention are simple. By precharging the voltage stabilizing capacitor, the current of the laser diode has a faster response speed and a larger current change rate.

[0023] 2. The present invention connects the voltage-stabilizing capacitor in parallel to both ends of the busbar, which effectively reduces the withstand voltage of the voltage-stabilizing capacitor, thereby reducing the volume of the voltage-stabilizing capacitor and achieving the purpose of reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The circuit diagram of the first embodiment of the diode driving circuit of the present invention;

[0025] Figure 2 is a control timing diagram of the diode driving circuit of the present invention;

[0026] Figure 3 A circuit diagram of a second embodiment of a diode driving circuit of the present invention;

[0027] Figure 4 A circuit diagram of a third embodiment of a diode driving circuit of the present invention;

[0028] Figure 5 A circuit diagram of a fourth embodiment of a diode driving circuit according to the present invention;

[0029] Figure 6 FIG. 5 is a circuit diagram of a fifth embodiment of a diode driving circuit according to the present invention. DETAILED DESCRIPTION

[0030] In the description of the present invention, "connection" may be a fixed connection, a direct connection, or an internal connection between two components. A person skilled in the art should understand that this embodiment is only one or more implementations of the present invention and does not limit the present invention.

[0031] In order to enable those skilled in the art to better understand the present invention, the present invention is further described below in conjunction with a specific implementation circuit.

[0032] First embodiment

[0033] Figure 1 A circuit diagram of a diode driving circuit of the present invention is shown, and the diode driving circuit includes an inductor L, a switch tube S1, an input capacitor C1, a voltage-stabilizing capacitor C2, a first switch unit, a second switch unit, a current sampling module 1, a current sampling module 2, a control module 1, a control module 2, and a switch branch 1 composed of a switch tube S2 and a laser diode component LD connected in series; wherein the first switch unit is composed of a diode D1, an anode of the diode D1 serves as a first end of the first switch unit, and a cathode of the diode D1 serves as a second end of the first switch unit; the second switch unit is composed of a diode D2, an anode of the diode D2 serves as a first end of the second switch unit, and a cathode of the diode D2 serves as a second end of the second switch unit.

[0034] One end of the input capacitor C1 is connected to one end of the inductor L and to the anode of the diode D1, the other end of the input capacitor C1 is connected to GND, the other end of the inductor L is connected to the drain of the switch tube S1 and the anode of the diode D2, the cathode of the diode D1 is connected to the anode of the laser diode assembly LD and the cathode of the diode D2, and the source of the switch tube S1 is connected to the ground through the current sampling module 1. The cathode of the laser diode assembly LD is connected to the drain of the switch tube S2, the source of the switch tube S2 is connected to the ground through the current sampling module 2, one end of the voltage stabilizing capacitor C2 is connected to the anode of the diode D1, and the other end of the voltage stabilizing capacitor C2 is connected to the cathode of the diode D1.

[0035] The control timing diagram of the diode driving circuit in this embodiment is as follows: Figure 2 As shown, D / A1 is the external control signal D / A1, D / A2 is the external control signal D / A2, S1 is the gate drive signal of the switch tube S1, V b is the voltage across switch branch 1, and LD is the current of the laser diode component, specifically:

[0036] Phase 1 (t1-t2): In this phase, the external control signals D / A1 and D / A2 are at high levels, the switch tube S2 is turned on, and the voltage-stabilizing capacitor C2 is in a discharging state, and together with the input capacitor C1, it supplies power to the laser diode component LD. The current of the laser diode component LD rises rapidly and stabilizes to the current setting value. At this time, the voltage of the voltage-stabilizing capacitor C2 drops to 0 potential.

[0037] Phase 2 (t2-t3): In this phase, the input voltage directly powers the laser diode component LD through the diode D2, ensuring that the current of the laser diode component LD is maintained stable at the current setting value during the high level of the external control signal D / A2.

[0038] Phase 3 (t3-t4): In this phase, the external control signal D / A2 is at a low level, the switch tube S2 is turned off, and in this interval, the switch tube S1 is turned on, and no current flows through the laser diode component LD.

[0039] Phase 4 (t4-t5): In this phase, the switch tube S1 is turned off, and the energy stored in the inductor L is The current change rate charges the voltage stabilizing capacitor C2 through the diode D2. According to the law of conservation of energy The voltage across the voltage stabilizing capacitor C2 is V C Rapidly rising, according to From the formula, when the parasitic inductance L1 of switch branch 1 remains unchanged, the voltage across the stabilizing capacitor V C Increases, causing Vb to increase, resulting in a current change rate The larger the value, the larger the current generated by the laser diode component LD in the same time, meeting the requirements of fast response and large current change rate. At the same time, since the voltage stabilizing capacitor C2 is located at both ends of the busbar and the charging voltage is low, the voltage stabilizing capacitor C2 can use a small volume capacitor with low withstand voltage, thereby reducing the cost.

[0040] Phase 5 (t5-t6): In this phase, the switch tubes S1 and S2 are both turned off, no current flows through the laser diode component LD, and the voltage across the voltage stabilizing capacitor C2 remains constant.

[0041] The working state of the stage (t6 to t11) is the same as that of the stage (t1 to t6).

[0042] Second embodiment

[0043] The circuit diagram of the second embodiment of the diode driving circuit of the present invention is as follows Figure 3 As shown, the difference between the diode driving circuit in this embodiment and the first embodiment is that in this embodiment, the diode D1 is replaced by a switch tube S3, and the diode D2 is replaced by a switch tube S4.

[0044] The control method of the diode driving circuit in this embodiment is the same as that in the first embodiment, and will not be described in detail here.

[0045] Third embodiment

[0046] The circuit diagram of the third embodiment of the diode driving circuit of the present invention is as follows Figure 4 As shown, the difference between the diode driving circuit in this embodiment and the first embodiment is that the second input end of the control module 1 is changed from being connected to the current sampling unit 1 to being connected to the pulse signal, and the pulse signal can be a pulse signal with a fixed pulse width or a pulse signal with a variable pulse width.

[0047] The control method of the diode driving circuit in this embodiment is different from that in the first embodiment in that the control mode of the switch tube S1 is changed from closed-loop control to open-loop control, and the rest are the same and will not be described in detail here.

[0048] Fourth embodiment

[0049] The circuit diagram of the fourth embodiment of the diode driving circuit of the present invention is as follows Figure 5 As shown, the difference between the diode driving circuit in this embodiment and the first embodiment is that the diode driving circuit in this embodiment is composed of a multi-stage boost circuit, thereby raising the voltage across the voltage-stabilizing capacitor C2, and finally raising the Vb voltage, thereby accelerating the rising speed of the current flowing through the laser diode component LD.

[0050] On the basis of the first embodiment, this embodiment adds an inductor Ln, a switch tube Sn, an nth switch unit, a current sampling unit n and a control module n, wherein the nth switch unit includes a diode Dn; a first end of the inductor Ln is connected to the anode of the diode D1, a second end of the inductor Ln is connected to the drain of the switch tube Sn and to the anode of the diode Dn, a cathode of the diode Dn is connected to one end of the voltage-stabilizing capacitor C2 and to the cathode of the diode D1; a first input end of the control module n is used to be connected to an external control signal D / An, a second input end of the control module n is connected to one end of the current sampling unit n, and an output end of the control module n is connected to the gate of the switch tube Sn.

[0051] In this embodiment, the control method of control module 1 is completely the same as that of control module 1 in embodiment 1; the control method of control module n is the same as that of control module 1.

[0052] Fifth embodiment

[0053] The circuit diagram of the fifth embodiment of the diode driving circuit of the present invention is as follows Figure 6 As shown, the difference between the diode driving circuit in this embodiment and the first embodiment is that: a voltage stabilizing capacitor C2n, a diode D1n, a diode D2n, a switch tube S1n and a control circuit 1n are added. Among them, the cathode of the diode D1 is connected to the anode of the diode D1n, the cathode of the diode D2 is connected to the anode of the diode D2n and the drain of the switch tube S1n, the cathode of the diode D1n is connected to the cathode of the diode D2n, the voltage stabilizing capacitor C2n is connected in parallel to both ends of the diode D1n, the first input end of the control module 1n is used to connect to the external control signal D / A1, the second input end of the control module 1n is connected to one end of the current sampling unit 1n, and the output end of the control module 1n is connected to the gate of the switch tube S1n.

[0054] The above are only preferred embodiments of the present invention. It should be pointed out that the above preferred embodiments should not be regarded as limiting the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention. For example, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. These improvements and modifications should also be regarded as the scope of protection of the present invention. The embodiments will not be repeated here. The scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A diode driving circuit, characterized in that: include: Inductor, switch tube S1, voltage stabilizing capacitor, input capacitor, first switch unit, second switch unit, control module 1, control module 2, and switch branch composed of switch tube S2 and laser diode assembly connected in series; The first end of the inductor is connected to the input capacitor and the first end of the first switch unit, the other end of the input capacitor is connected to the ground, the second end of the inductor is respectively connected to the first end of the second switch unit and the drain of the switch tube S1; the second end of the first switch unit is connected to the switch branch and connected to the second end of the second switch unit; the voltage stabilizing capacitor is connected in parallel with the first switch unit; The control module 1 is connected to the gate of the switch tube S1; The control module 2 is connected to the gate of the switch tube S2.

2. The diode driving circuit according to claim 1, characterized in that: The first switch unit is composed of a diode D1, the anode of the diode D1 serves as the first end of the first switch unit, and the cathode of the diode D1 serves as the second end of the first switch unit; the second switch unit is composed of a diode D2, the anode of the diode D2 serves as the first end of the second switch unit, and the cathode of the diode D2 serves as the second end of the second switch unit.

3. The diode driving circuit according to claim 2, characterized in that: The first switch unit is composed of a switch tube S3, the drain of the switch tube S3 serves as the first end of the first switch unit, and the source of the switch tube S3 serves as the second end of the first switch unit; the second switch unit is composed of a switch tube S4, the drain of the switch tube S4 serves as the first end of the second switch unit, and the source of the switch tube S4 serves as the second end of the second switch unit.

4. The diode driving circuit according to claim 1, characterized in that: A current sampling module 1 and a current sampling module 2 are also provided. The source of the switch tube S1 is connected to the ground through the current sampling module 1, and the current sampling module 1 is used to sample the current flowing through the switch tube S1 to control the current flowing through the inductor; the source of the switch tube S2 is connected to the ground through the current sampling module 2, and the current sampling module 2 is used to sample the current flowing through the switch tube S2 to control the current flowing through the laser diode component.

5. The diode driving circuit according to claim 1, characterized in that: The first input end of the control module 1 is used to connect to an external control signal, the second input end of the control module 1 is connected to one end of the current sampling unit 1 to generate a pulse signal, the output end of the control module 1 is connected to the gate of the switch tube S1, and the control module 1 is used to control the current flowing through the inductor according to the pulse signal; The first input end of the control module 2 is used to connect to the external control signal, the second input end of the control module 2 is connected to one end of the current sampling unit 2 to generate a control signal, the output end of the control module 2 is connected to the gate of the switch tube S2, and the control module 2 is used to control the current flowing through the laser diode according to the current sampling signal I2.

6. A control method for the diode driving circuit according to claim 1, characterized in that: include: Receiving an external control signal D / A1 through the control module 1; In the current cycle, a pulse signal is generated according to the falling edge of the control signal D / A1 to control the switch tube S1 to be turned on, so that the inductor stores energy; After the switch tube S1 is turned on for a period of time, the switch tube S1 is controlled to be turned off, so that after the switch tube S1 is turned off, the inductor charges the voltage stabilizing capacitor through the loop.

7. The control method of the diode driving circuit according to claim 6, characterized in that: The diode driving control method further includes: In the next cycle of the current cycle, the control module 2 receives the external control signal D / A2, and when the rising edge of the external control signal D / A2 is generated, the control module 2 controls the switch tube S2 to be turned on, so as to control the current of the laser diode component; When the falling edge of the external control signal 2 is generated, the switch tube S2 is controlled to be turned off through the control module 2 .

8. The control method of the diode driving circuit according to claim 6, characterized in that: The pulse width of the pulse signal is narrower than that of the external control signal D / A1 and the external control signal D / A2, respectively.

9. The control method of the diode driving circuit according to claim 6, characterized in that: The pulse signal is a pulse with a fixed duty cycle or a pulse with a variable pulse width.

10. The control method of the diode driving circuit according to claim 6, characterized in that: The external control signal D / A1 and the external control signal D / A2 come from the same given control signal, or come from two separate given signals.

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