CN114865900B - Overshoot suppression circuit and constant current driving device - Google Patents

Abstract

The invention discloses an overshoot suppression circuit and a constant current driving device. The overshoot suppression circuit includes: the constant current driving circuit, the load circuit, the switch circuit, the sampling circuit and the feedback circuit; the constant current driving circuit comprises a constant current output end and an electric signal receiving end; the sampling circuit is used for feeding back a sampling signal to the electric signal receiving end according to the electric signal flowing through the switching circuit; the switch circuit is used for being switched on or switched off under the control of the external controller; the feedback circuit is used for providing a feedback signal to the electric signal receiving end under the control of the external controller at least before the switching circuit is conducted; the constant current driving circuit is used for outputting a constant current signal according to the feedback signal and/or the sampling signal. By adopting the technical scheme, the phenomenon that when the switch circuit is switched on, a loop where the load circuit is located generates transient overshoot current can be avoided, and the transient overshoot current can be remarkably inhibited.

Description

Overshoot suppression circuit and constant current driving device

Technical Field

The invention relates to the technical field of vision, in particular to an overshoot suppression circuit and a constant current driving device.

Background

With the development of vision technology, a laser as a device capable of emitting laser light may be provided in an imaging device, for example, a structured light projector, a floodlight, an infrared camera, a color camera, and the like. Because of the load characteristic of the laser, a constant current power supply circuit is needed in the working process of the laser, namely, the power grid energy is converted into constant current energy needed by the laser to work.

The influence of product consumption, heat accumulation etc. to the laser instrument is considered in current device, and the laser instrument can not normally open, can open the laser instrument again when the camera is shot, closes the laser instrument after the camera is shot to the end. When the laser is turned off and turned on frequently, no load exists in the constant current driving circuit when the laser is turned off, so that the voltage of a constant current signal in the constant current driving circuit is increased to the input voltage of the constant current driving circuit, and transient overshoot current is formed when the laser is turned on to damage the laser.

Disclosure of Invention

The invention provides an overshoot suppression circuit and a constant current driving device, which aim to solve the problem of current overshoot of a constant current driving circuit.

According to an aspect of the present invention, there is provided an overshoot suppression circuit, including a constant current drive circuit, a load circuit, a switch circuit, a sampling circuit, and a feedback circuit;

the constant current driving circuit comprises a constant current output end and an electric signal receiving end; the load circuit and the switch circuit are connected in series between the constant current output end and the sampling circuit; the sampling circuit is electrically connected with the electric signal receiving end; the output end of the feedback circuit is electrically connected with the electric signal receiving end; the control end of the feedback circuit and the control end of the switch circuit are both electrically connected with an external controller;

the sampling circuit is used for feeding back a sampling signal to the electric signal receiving end according to the electric signal flowing through the switch circuit;

the switch circuit is used for being switched on or switched off under the control of the external controller;

the feedback circuit is used for providing a feedback signal to the electric signal receiving end under the control of the external controller and at least before the switch circuit is switched on;

the constant current driving circuit is used for outputting a constant current signal according to the feedback signal and/or the sampling signal.

Optionally, the method further includes: a power supply circuit;

the constant current driving circuit also comprises a power supply end; the power supply circuit is electrically connected with the power supply end; the constant current driving circuit is further used for converting a power supply signal provided by the power supply circuit into the constant current signal according to the feedback signal and/or the sampling signal.

Optionally, the power supply circuit includes a first voltage converter, a second current-limiting resistor, a third filter capacitor, and a fourth filter capacitor;

the first end of the second current-limiting resistor is electrically connected with the first voltage converter; the second end of the second current-limiting resistor is electrically connected with the power supply end; first ends of the third filter capacitor and the fourth filter capacitor are electrically connected with a second end of the second current-limiting resistor; and the second ends of the third filter capacitor and the fourth filter capacitor are both grounded.

Optionally, the feedback circuit includes a triode; the input end of the triode is electrically connected with the power supply circuit; the output end of the triode is electrically connected with the electric signal receiving end; and the control end of the triode is electrically connected with the external controller.

Optionally, the conduction time of the triode overlaps with the conduction time of the switching circuit.

Optionally, the load circuit comprises a laser.

Optionally, the switching circuit includes a MOS transistor;

the first pole of the MOS tube is electrically connected with the load circuit; the second pole of the MOS tube is electrically connected with the sampling circuit; and the control end of the MOS transistor is electrically connected with the external controller.

Optionally, the sampling circuit includes a first sampling resistor and a second sampling resistor connected in parallel.

According to another aspect of the present invention, there is provided a constant current driving device including: a signal processing circuit and the overshoot suppression circuit;

the signal processing circuit includes an external controller electrically connected to the feedback circuit in the overshoot suppression circuit; the signal processing circuit further comprises an external controller electrically connected to the switch circuit in the overshoot suppression circuit;

the signal processing circuit is used for controlling the on or off of the switch circuit;

the signal processing circuit is further used for controlling the feedback circuit to provide a feedback signal to an electric signal receiving end of the constant current driving circuit at least before the switching circuit is conducted.

Optionally, the signal processing circuit includes a first controller and a second controller; the first controller and the second controller are different controllers;

the first controller is used for controlling the feedback circuit to provide a feedback signal to an electric signal receiving end which outputs the constant current driving current at least before the switch circuit is switched on;

the second controller is used for controlling the switch circuit to be switched on or switched off.

According to the technical scheme, the constant current driving circuit is arranged, so that a constant current signal can be output when a feedback signal and/or a sampling signal is received, and a stable constant current signal is provided for the load circuit; by arranging the switch circuit, the on-off state of a loop where the load circuit is located can be controlled; by arranging the sampling circuit, a sampling signal can be fed back to the constant current driving circuit when a loop where the load circuit is located is conducted, so that the constant current driving circuit can continuously provide a stable constant current signal for the load circuit; by arranging the feedback circuit, the feedback signal can be provided to the constant current driving circuit before the switching circuit is switched on, and the voltage rise of the constant current signal is restrained when the constant current driving circuit is in no-load state, so that when the switching circuit is switched on, the constant current driving circuit can provide a stable constant current signal for the load circuit, the phenomenon that when the switching circuit is switched on, a loop where the load circuit is located generates transient overshoot current is avoided, and the transient overshoot current can be restrained remarkably.

It should be understood that the statements in this section do not necessarily identify key or critical features of the embodiments of the present invention, nor do they necessarily limit the scope of the invention. Other features of the present invention will become apparent from the following description.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an overshoot suppression circuit according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention;

FIG. 7 is a timing diagram of a control signal according to an embodiment of the present invention;

FIG. 8 is a timing diagram of another control signal according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a constant current driving device according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of another constant current driving device according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in other sequences than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 1 is a schematic structural diagram of an overshoot suppression circuit according to an embodiment of the present invention. Referring to fig. 1, the overshoot suppression circuit 10 includes a constant current drive circuit 100, a load circuit 200, a switch circuit 300, a sampling circuit 400, and a feedback circuit 500. The constant current driving circuit 100 comprises a constant current output end 101 and an electric signal receiving end 102; the load circuit 200 and the switch circuit 300 are connected in series between the constant current output terminal 101 and the sampling circuit 400; the sampling circuit 400 is electrically connected with the electrical signal receiving end 102; the output end 502 of the feedback circuit 500 is electrically connected with the electric signal receiving end 102; the control terminal 501 of the feedback circuit 500 and the control terminal 301 of the switch circuit 300 are both electrically connected to an external controller (not shown).

The sampling circuit 400 is configured to feed back a sampling signal to the electrical signal receiving end 102 according to the electrical signal flowing through the switching circuit 300; the switch circuit 300 is used for being switched on or off under the control of an external controller; the feedback circuit 500 is configured to provide a feedback signal to the electrical signal receiving terminal 102 at least before the switching circuit 300 is turned on under the control of the external controller; the constant current driving circuit 100 is configured to output a constant current signal according to a feedback signal and/or a sampling signal.

Specifically, the constant current driving circuit 100 may provide a constant current signal to the load circuit 200 when the electrical signal receiving terminal 102 receives a feedback signal and/or a sampling signal, so that the load of the load circuit 200 operates normally; the switch circuit 300 can control the on/off of the loop of the load circuit 200, when the switch circuit 300 is on, the loop of the load circuit 200 is also on, and when the switch circuit 300 is off, the loop of the load circuit 200 is also off; the sampling circuit 400 can collect the electrical signals flowing through the load circuit 200 and the switch circuit 300, and feed back the sampling signals to the electrical signal receiving end 102 of the constant current driving circuit 100, so that the constant current driving circuit 100 can continuously provide the constant current signals to the load circuit 200; the feedback circuit 500 may provide a feedback signal to the electrical signal receiving terminal 102 of the constant current driving circuit 100 before the switch circuit 300 is changed from the off state to the on state under the control of the external controller, so that the constant current driving circuit 100 may provide a constant current signal to the load circuit 200 when the switch circuit 300 is changed from the off state to the on state.

Illustratively, the constant current driving circuit 100 may be used in a face recognition device, an image recognition device, and the like, and provides constant current energy required for operation of a laser in the face recognition device, the image recognition device, and the like. Fig. 2 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention. Referring to fig. 2, the constant current driving circuit 100 includes a constant current driving chip 110, an upper bridge lift capacitor C501, a power inductor L502, a current limiting resistor R503, a filter capacitor C504, a filter capacitor C505, a current limiting resistor R504, and a filter capacitor C506; the constant current driving chip 110 includes a feedback pin 01, an enable pin 02, a ground pin 03, a power pin 04, a first output terminal 05, and a second output terminal 06. A first end of the upper bridge lifting capacitor C501 is electrically connected to the first output end 05, and a second end of the upper bridge lifting capacitor C501 is electrically connected to the second output end 06, so as to stabilize an electrical signal output by the first output end 05; the first end of the power inductor L502 is electrically connected to the first output terminal 05, the second end of the power inductor L502 is electrically connected to the load circuit 200, and the power inductor L502 can play a role of filtering to prevent oscillation of an electrical signal output by the first output terminal 05; a first end of the current limiting resistor R503 is electrically connected with the feedback pin 01, a second end of the current limiting resistor R503 is electrically connected with the sampling circuit 400, first ends of the filter capacitor C504 and the filter capacitor C505 are electrically connected with a second end of the power inductor L502, and second ends of the filter capacitor C504 and the filter capacitor C505 are electrically connected with a second end of the current limiting resistor R503; the current-limiting resistor R504 and the filter capacitor C506 are both electrically connected with the enable pin 02 to play a role in filtering. The constant current driving circuit 100 may further include a control terminal 104 connected to an external controller (not shown), and the external controller may control whether the constant current driving circuit 100 operates. When the constant current driving circuit 100 is in a working state, the enable pin 02 of the constant current driving chip 110 receives a control signal, and when the feedback pin 01 receives a feedback signal and/or a sampling signal, the first output terminal 05 may output a relatively stable constant current signal, and the constant current output terminal 101 may output a stable constant current signal through the upper bridge lifting capacitor C501, the power inductor L502, the filter capacitor C504, and the filter capacitor C505.

It can be understood that fig. 3 is a schematic structural diagram of another overshoot suppression circuit provided in the embodiment of the present invention. Referring to fig. 3, the output terminal 502 of the feedback circuit 500 may also be directly electrically connected to the feedback pin 01 of the constant current driving chip 110.

According to the embodiment of the invention, the constant current driving circuit is arranged, so that a constant current signal can be output when a feedback signal and/or a sampling signal is received, and a stable constant current signal is provided for a load circuit; by arranging the switch circuit, the on-off state of a loop where the load circuit is located can be controlled; by arranging the sampling circuit, when a loop where the load circuit is located is conducted, a sampling signal can be fed back to the constant current driving circuit, so that the constant current driving circuit can continuously provide a stable constant current signal for the load circuit; by arranging the feedback circuit, a feedback signal can be provided to the constant current driving circuit before the switching circuit is switched on, and the voltage rise of the constant current signal is inhibited when the constant current driving circuit is in no-load state, so that the constant current driving circuit can provide a stable constant current signal to the load circuit when the switching circuit is switched on, the transient overshoot current generated by a loop where the load circuit is located when the switching circuit is switched on is avoided, and the transient overshoot current can be obviously inhibited.

It should be noted that fig. 1 and fig. 2 are merely exemplary to electrically connect the load circuit 200 directly to the constant current driving circuit 100, to electrically connect the switch circuit 300 directly to the sampling circuit 400, and to electrically connect the load circuit 200 to the switch circuit 300; the switch circuit 300 may be directly electrically connected to the constant current drive circuit 100, the load circuit 200 may be directly electrically connected to the sampling circuit 400, and the switch circuit 300 may be electrically connected to the load circuit 200. For convenience of understanding, the former connection relationship is taken as an example for description in the embodiments of the present invention, and the latter connection condition is not described again.

Optionally, with continued reference to fig. 2, the overshoot suppression circuit 10 further comprises a power supply circuit 600; the constant current driving circuit 100 further includes a power supply terminal 103; the power supply circuit 600 is electrically connected to the power supply terminal 103. The constant current driving circuit 100 is further configured to convert a power supply signal provided by the power supply circuit 600 into a constant current signal according to a feedback signal and/or a sampling signal.

For example, the power supply circuit 600 may provide a 5V power supply signal to the constant current driving circuit 100, and the constant current driving circuit 100 may convert the 5V power supply signal into a 2.5V constant current signal when receiving the feedback signal and/or the sampling signal. It is understood that the power supply circuit 600 may also be electrically connected to the feedback circuit 500, for example, a 1.8V power supply signal may be provided to the feedback circuit 500.

Optionally, fig. 4 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention. Referring to fig. 4, the power supply circuit 600 includes a first voltage converter 610, a second current limiting resistor R501, a third filter capacitor C503, and a fourth filter capacitor C502. A first end of the second current limiting resistor R501 is electrically connected to the first voltage converter 610; a second end of the second current-limiting resistor R501 is electrically connected to the power supply end 103 of the constant current driving circuit 100; first ends of the third filter capacitor C503 and the fourth filter capacitor C502 are electrically connected with a second end of the second current limiting resistor R501; second ends of the third filter capacitor C503 and the fourth filter capacitor C502 are both grounded.

For example, the first voltage converter 610 may be a DC/DC converter, and converts an external electrical signal into a power supply signal to be transmitted to the constant current driving circuit 100. The third filter capacitor C503 and the fourth filter capacitor C502 are connected in parallel to form a filter capacitor of 10 μ F or more, which can suppress the interference of external signals and prevent the voltage collapse caused by the moment when the switch circuit 300 is turned on. The power supply circuit 600 may further include a second voltage converter 620 and a filter capacitor C520, and the second voltage converter 620 may be another DC/DC converter, and converts an external electrical signal into a power supply signal to be transmitted to the feedback circuit 500.

Optionally, fig. 5 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention. Referring to fig. 5, the sampling circuit 400 includes a first sampling resistor R506 and a second sampling resistor R507 connected in parallel.

Illustratively, first ends of the first sampling resistor R506 and the second sampling resistor R507 are electrically connected to the switch circuit 300, second ends of the first sampling resistor R506 and the second sampling resistor R507 are grounded, and first ends of the first sampling resistor R506 and the second sampling resistor R507 are also electrically connected to the electrical signal receiving end 102 of the constant current driving circuit 100. The first sampling resistor R506 and the second sampling resistor R507 may both be high-precision resistors, when the switch circuit 300 is turned on, a constant current signal may flow through the load circuit 200, the switch circuit 300, the first sampling resistor R506 and the second sampling resistor R507 to ground, and a voltage may be generated when a current flows through the first sampling resistor R506 and the second sampling resistor R507, and the voltage may be fed back to the electrical signal receiving terminal 102 as a sampling signal, so that the constant current driving circuit 100 adjusts the output current to a set value, and a constant current purpose is achieved.

Optionally, with continued reference to fig. 5, the feedback circuit 500 includes a transistor Q502; the input end of the triode Q502 is electrically connected with the power supply circuit 600; the output end of the triode Q502 is electrically connected with the electric signal receiving end 102; the control terminal of the transistor Q502 is electrically connected to an external controller (not shown).

For example, referring to fig. 5, the transistor Q502 is a PNP transistor. The feedback circuit 500 may further include a current limiting resistor R532 and a voltage dividing resistor R534. The emitter of the transistor Q502 may be directly electrically connected to the power supply circuit 600, the collector of the transistor Q502 may be electrically connected to the electrical signal receiving terminal 102 through a voltage dividing resistor R534, and the base of the transistor Q502 may be electrically connected to an external controller (not shown in the figure) through a current limiting resistor R532. When an external controller provides a low-level control signal to the control terminal 501 of the feedback circuit 500, the transistor Q502 is turned on, the power supply signal provided by the power supply circuit 600 to the feedback circuit 500 flows through the transistor Q502, the voltage dividing resistor R534, the current limiting resistor R503, the first sampling resistor R506 and the second sampling resistor R507, and by reasonably selecting the resistance values of the voltage dividing resistor R534, the current limiting resistor R503, the first sampling resistor R506 and the second sampling resistor R507, when the switch circuit 300 is turned off, the output terminal 502 of the feedback circuit 500 can output feedback information, which is the same as the voltage of the sampling signal when the switch circuit 300 is turned on, to the electric signal receiving terminal 102, so that the constant current driving circuit 100 adjusts the output current to the same setting value when the switch circuit 300 is turned on, thereby avoiding the generation of transient overshoot current when the switch circuit 300 is turned on.

Optionally, fig. 6 is a schematic structural diagram of another overshoot suppression circuit according to an embodiment of the present invention. Referring to fig. 6, the switching circuit 300 includes a MOS transistor Q501, and a first pole of the MOS transistor Q501 is electrically connected to the load circuit 200; the second pole of the MOS transistor Q501 is electrically connected with the sampling circuit 400; the control terminal of the MOS transistor Q501 is electrically connected to an external controller.

For example, referring to fig. 6, the MOS transistor Q501 is an N-type MOS transistor. The switching circuit 300 further includes a current limiting resistor R508 and a filter capacitor C508. The drain of the MOS transistor Q501 is electrically connected to the load circuit 200, the source of the MOS transistor Q501 is electrically connected to the sampling circuit 400, and the gate of the MOS transistor Q501 is electrically connected to an external controller (not shown) through a current limiting resistor R508. When the external controller provides a high-level control signal to the control terminal 301 of the switch circuit 300, the MOS transistor Q501 is turned on, i.e., the circuit in which the load circuit 200 is located is turned on.

Optionally, the conduction time of the transistor Q502 overlaps with the conduction time of the switch circuit 300.

For example, in the embodiments of the present invention, the transistor Q502 is a PNP transistor, and the MOS transistor Q501 is an N-type MOS transistor for convenience of understanding. Fig. 7 is a timing diagram of a control signal according to an embodiment of the present invention, which includes a timing relationship between the control signal CK at the control terminal 501 of the feedback circuit 500 and the control signal CK at the control terminal 301 of the switch circuit 300. Referring to fig. 7, when the control signal CK of the control terminal 501 is at a low level, the transistor Q502 is turned on, and when the control signal CK of the control terminal 301 is at a high level, the MOS transistor Q501 is turned on. The rising edge of the control signal ck of the control end 301 is the conduction time of the MOS transistor Q501, and the transistor Q502 is already in a conduction state before the MOS transistor Q501 is conducted; the rising edge of the control signal CK of the control terminal 501 is the disconnection time of the triode Q502, and when the triode Q502 is disconnected, the MOS transistor Q501 is still in a conduction state; the falling edge of the control signal ck of the control terminal 301 is the disconnection time of the MOS transistor Q501, and when the MOS transistor Q501 is disconnected, the triode Q502 is still in a disconnected state. The conduction time of the feedback circuit 500 overlaps the conduction time of the switch circuit 300, and the overlapping time is the time between the conduction time of the MOS transistor Q501 and the disconnection time of the transistor Q502, i.e., the time interval t. FIG. 8 is a timing diagram of another control signal according to an embodiment of the present invention. Referring to fig. 8, a rising edge of the control signal ck of the control terminal 301 is a conduction time of the MOS transistor Q501, and the MOS transistor Q501 is already in a conduction state when conducting the triac Q502; the rising edge of the control signal CK of the control terminal 501 is the disconnection time of the triode Q502, and when the triode Q502 is disconnected, the MOS transistor Q501 is still in a conduction state; the falling edge of the control signal CK of the control terminal 501 is the conduction time of the triode Q502, and when the triode Q502 is conducted, the MOS transistor Q501 is still in a conduction state; the falling edge of the control signal ck of the control terminal 301 is the off time of the MOS transistor Q501, and when the MOS transistor Q501 is off, the triode Q502 is still in a conducting state. The conduction time of the feedback circuit 500 overlaps the conduction time of the switch circuit 300, and the overlapping time is the conduction time of the MOS transistor Q501 minus the off time of the transistor Q502, i.e. the time interval t1+ t2. It should be noted that, the conduction time of the transistor Q502 may overlap with the conduction time of the switch circuit 300, and embodiments of the present invention are not described one by one.

Optionally, with continued reference to fig. 6, the load circuit 200 includes a laser LED1.

For example, the laser LED1 may be a Vertical-cavity surface-emitting laser (VCSEL) structured light module, and may be applied to 3D vision technology. The load circuit 200 may also include a current limiting resistor R502. The positive electrode of the Vcsel structured light module is electrically connected with the constant current output end 101 of the constant current driving circuit 100 through the current limiting resistor R502, and the negative electrode of the Vcsel structured light module is electrically connected with the switch circuit 300. It is understood that the load circuit 200 may further include a light-emitting load such as a light-emitting diode (LED) or other types of non-light-emitting loads, which are not listed in the embodiments of the present invention.

Fig. 9 is a schematic structural diagram of a constant current driving device according to an embodiment of the present invention. Referring to fig. 9, the constant current driving device 30 includes a signal processing circuit 20 and an overshoot suppression circuit 10 provided in any embodiment of the present invention. The signal processing circuit 20 includes an external controller (not shown in the figure) electrically connected to the feedback circuit 500 in the overshoot suppression circuit 10; the signal processing circuit 20 further includes an external controller (not shown) electrically connected to the switching circuit 300 of the overshoot suppression circuit 10.

The signal processing circuit 20 is configured to control the switch circuit 300 to be turned on or off; the signal processing circuit 20 is further configured to control the feedback circuit 500 to provide the feedback signal to the electrical signal receiving terminal 102 of the constant current driving circuit 100 at least before the switch circuit 300 is turned on.

Illustratively, the constant current driving device 30 may be a human face recognition device, an image recognition device, etc., the load circuit 200 includes a laser, the signal processing circuit 20 may be a main controller inside the constant current driving device 30, on/off of the switching circuit 300 and the feedback circuit 500 may be respectively controlled according to the timing relationship of fig. 7 or fig. 8, so that the laser may be periodically lighted, and the feedback circuit 500 may provide a feedback signal to the electrical signal receiving terminal 102 of the constant current driving circuit 100 before the switching circuit 300 is turned on.

According to the embodiment of the invention, the stable constant current signal can be provided for the load circuit by arranging the signal processing circuit and the overshoot suppression circuit; the signal processing circuit can control the feedback circuit to provide a feedback signal to the constant current driving circuit before the switching circuit is conducted, so that the voltage rise of the constant current signal can be inhibited when the constant current driving circuit is in no-load, the constant current driving circuit can provide a stable constant current signal to the load circuit when the signal processing circuit controls the switching circuit to be conducted, the transient overshoot current generated by a loop where the load circuit is located when the switching circuit is conducted is avoided, and the transient overshoot current can be obviously inhibited.

Optionally, fig. 10 is a schematic structural diagram of another constant current driving device according to an embodiment of the present invention. Referring to fig. 10, the signal processing circuit 20 includes a first controller 021 and a second controller 022; the first controller 021 and the second controller 022 are different controllers. The first controller 021 is configured to control the feedback circuit 500 to provide a feedback signal to the electrical signal receiving terminal 102 of the constant current driving circuit 100 at least before the switching circuit 300 is turned on; the second controller 022 is used to control the switching circuit 300 to be turned on or off.

Illustratively, the first controller 021 may be an infrared camera, and the second controller 022 may be a controller that controls the periodic firing of the laser in the load circuit 200. When the laser does not need to be polished, the switching circuit 300 is in a disconnected state, at this time, the infrared camera does not work, the infrared camera outputs low-level pulse information to the feedback circuit 500, the triode Q502 of the feedback circuit 500 is connected, and the feedback circuit 500 can provide a feedback signal to the electric signal receiving end 102 of the constant current driving circuit 100; when the laser needs to be polished, the switching circuit 300 is turned on, and the sampling circuit 400 can feed back sampling information to the electrical signal receiving end 102 of the constant current driving circuit 100; after the switch circuit 300 is turned on, the infrared camera starts to operate (ready for exposure), the infrared camera starts to output high-level pulse information to the feedback circuit 500, and the transistor Q502 of the feedback circuit 500 is turned off. The feedback signal and the sampling signal are successively provided to the electric signal receiving end 102 of the constant current driving circuit 100, and can be seamlessly connected, and the cycle is repeated, so that the voltage of the constant current signal is suppressed each time the constant current driving circuit 100 is in no-load, the transient overshoot current generated by the loop where the load circuit 200 is located when the switch circuit 300 is switched on is avoided, and the transient overshoot current can be remarkably suppressed.

It is to be noted that the foregoing description is only exemplary of the invention and that the principles of the technology may be employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (8)

1. An overshoot suppression circuit is characterized by comprising a constant current driving circuit, a load circuit, a switching circuit, a sampling circuit and a feedback circuit;

the constant current driving circuit comprises a constant current output end and an electric signal receiving end; the load circuit and the switch circuit are connected in series between the constant current output end and the sampling circuit; the sampling circuit is electrically connected with the electric signal receiving end; the output end of the feedback circuit is electrically connected with the electric signal receiving end; the control end of the feedback circuit and the control end of the switch circuit are both electrically connected with an external controller;

the sampling circuit is used for feeding back a sampling signal to the electric signal receiving end according to the electric signal flowing through the switch circuit;

the switch circuit is used for being switched on or switched off under the control of the external controller;

the feedback circuit is used for providing a feedback signal to the electric signal receiving end at least before the switch circuit is conducted under the control of the external controller;

the constant current driving circuit is used for outputting a constant current signal according to the feedback signal and/or the sampling signal;

the overshoot suppression circuit further comprises a power supply circuit;

the feedback circuit comprises a triode; the input end of the triode is electrically connected with the power supply circuit; the output end of the triode is electrically connected with the electric signal receiving end; the control end of the triode is electrically connected with the external controller; the triode is conducted before the switching circuit is conducted, and the conducting time of the triode is overlapped with the conducting time of the switching circuit.

2. The overshoot suppression circuit according to claim 1, wherein the constant current drive circuit further comprises a power supply terminal; the power supply circuit is electrically connected with the power supply end; the constant current driving circuit is further used for converting a power supply signal provided by the power supply circuit into the constant current signal according to the feedback signal and/or the sampling signal.

3. The overshoot suppression circuit of claim 2, wherein the power supply circuit comprises a first voltage converter, a second current limiting resistor, a third filter capacitor, and a fourth filter capacitor;

the first end of the second current limiting resistor is electrically connected with the first voltage converter; the second end of the second current-limiting resistor is electrically connected with the power supply end; the first ends of the third filter capacitor and the fourth filter capacitor are electrically connected with the second end of the second current-limiting resistor; and the second ends of the third filter capacitor and the fourth filter capacitor are grounded.

4. The overshoot suppression circuit in accordance with claim 1 wherein the load circuit comprises a laser.

5. The overshoot suppression circuit according to claim 1, wherein the switching circuit comprises a MOS transistor;

the first pole of the MOS tube is electrically connected with the load circuit; the second pole of the MOS tube is electrically connected with the sampling circuit; and the control end of the MOS tube is electrically connected with the external controller.

6. The overshoot suppression circuit in accordance with claim 1, wherein the sampling circuit comprises a first sampling resistor and a second sampling resistor connected in parallel.

7. A constant current driving device characterized by comprising: a signal processing circuit and an overshoot suppression circuit as claimed in any one of claims 1 to 6;

the signal processing circuit comprises an external controller electrically connected with the feedback circuit in the overshoot suppression circuit; the signal processing circuit further comprises an external controller electrically connected with the switch circuit in the overshoot suppression circuit;

the signal processing circuit is used for controlling the on or off of the switch circuit;

the signal processing circuit is also used for controlling the feedback circuit to provide a feedback signal to an electric signal receiving end of the constant current driving circuit at least before the switching circuit is switched on.

8. The constant-current driving device according to claim 7, wherein the signal processing circuit includes a first controller and a second controller; the first controller and the second controller are different controllers;

the first controller is used for controlling the feedback circuit to provide a feedback signal to an electric signal receiving end of the constant current driving circuit at least before the switching circuit is switched on;

the second controller is used for controlling the switch circuit to be switched on or switched off.

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