Control circuit and constant current source circuit

Abstract

The utility model provides a control circuit and a constant current source circuit, and the control circuit comprises a control switch which is connected between the negative electrode of a power supply and a load, and is a transistor; the output end of the operational amplifier is connected with the grid electrode of the control switch, and the output voltage of the operational amplifier is used for controlling the on-off state of the control switch; and the voltage stabilizing circuit is connected with the operational amplifier in parallel, and the voltage stabilizing circuit receives the control signal and controls the output voltage of the operational amplifier. Through the mode, the structure is simple, the conduction state of the control switch can be controlled, the current flowing through the control switch is controlled, current overshoot is prevented, the load performance is protected, the stability of the circuit is improved, and the maintenance cost of the circuit is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuit, in particular to a control circuit and a constant current source circuit. BACKGROUND

[0002] In the existing electronic circuit design, the constant current source circuit is widely used in the diode device and the laser circuit due to its fast response speed and simple control.

[0003] In practical application, due to the change of external environment or the change of circuit load, the current fluctuation may be caused, and the slight change of current may cause the significant decline of device performance, overload and even damage.

[0004] In order to ensure the safe and stable operation of the circuit device, it is of great significance to set certain protection measures for improving the reliability of electronic device and prolonging its service life. CONTENT OF THE INVENTION

[0005] The present application provides a control circuit and a constant current source circuit, which has simple structure, can control the conduction state of the control switch, control the current flowing through the control switch, prevent current overshoot, protect the load performance, improve the stability of the circuit, and is conducive to reducing the maintenance cost of the circuit.

[0006] To solve the above technical problems, the first aspect of the present application provides a control circuit.

[0007] The control circuit comprises: a control switch connected between the negative electrode of a power supply and a load, the control switch being a transistor; an operational amplifier, an output end of the operational amplifier being connected to a gate of the control switch, and an output voltage of the operational amplifier being used to control the on-off state of the control switch; and a voltage stabilizing circuit, the voltage stabilizing circuit being connected to the operational amplifier in parallel, receiving a control signal, and controlling the output voltage of the operational amplifier.

[0008] The voltage stabilizing circuit comprises: a first voltage stabilizing circuit and a second voltage stabilizing circuit, the first voltage stabilizing circuit and the second voltage stabilizing circuit being connected to the operational amplifier in parallel, the first voltage stabilizing circuit and the second voltage stabilizing circuit being connected to an output end and a reverse input end of the operational amplifier respectively; and the voltage stabilizing circuit controls the on-off of the second voltage stabilizing circuit according to the control signal, and controls the output voltage of the operational amplifier.

[0009] The on voltage of the first voltage stabilizing circuit is higher than the on voltage of the second voltage stabilizing circuit; when the control signal received by the voltage stabilizing circuit is an on signal, the second voltage stabilizing circuit is controlled to be disconnected, and the output voltage of the operational amplifier is controlled to be the on voltage of the first voltage stabilizing circuit; or when the control signal received by the voltage stabilizing circuit is an off signal, the second voltage stabilizing circuit is controlled to be turned on, and the output voltage of the operational amplifier is controlled to be the on voltage of the second voltage stabilizing circuit.

[0010] The first voltage stabilizing circuit comprises a first voltage stabilizing element, the second voltage stabilizing circuit comprises a second voltage stabilizing element, a first switch and a second switch, the on-voltage of the first voltage stabilizing element is higher than the on-voltage of the second voltage stabilizing element; the first switch and the second switch are transistors; the second voltage stabilizing element is connected with the drain of the first switch and the drain of the second switch in series, the source of the first switch is connected with the inverting input terminal of the operational amplifier, and the source of the second switch is grounded; the gate of the first switch and the gate of the second switch receive a control signal which is an off signal, the first switch is turned on to make the second voltage stabilizing circuit reach the on-current of the second voltage stabilizing element, and the second switch is turned on.

[0011] The second voltage stabilizing circuit further comprises a third switch which is a transistor; the drain of the third switch is connected with the gate of the first switch and the gate of the second switch; the gate of the third switch receives a control signal which is a turn-on signal, and controls the off of the third switch to make the first switch and the second switch be turned on; or, the gate of the third switch receives a control signal which is an off signal, and controls the turn-on of the third switch to make the first switch and the second switch be turned off.

[0012] The control circuit comprises a control switch feedback circuit which is connected with the inverting input terminal of the operational amplifier and receives the voltage of the circuit where the control switch is located; the operational amplifier collects the voltage of the circuit which exceeds the threshold voltage, and sends a control signal to control the off of the control switch.

[0013] The control circuit comprises an operational amplifier feedback circuit which is connected with the operational amplifier in parallel, and the operational amplifier feedback circuit comprises a feedback capacitor and a feedback resistor to control the change rate of the output voltage of the operational amplifier.

[0014] To solve the above technical problems, the second aspect of the present application provides a constant current source circuit, characterized in that the constant current source circuit comprises a driving switch and a control circuit; the driving switch is arranged between the positive electrode of a power supply and the positive terminal of a load; the driving switch receives a control signal and turns on or turns off the driving switch in response to the control signal; the control circuit comprises a control switch, the control switch is connected between the negative electrode of the power supply and the load, and the control switch is a transistor; an operational amplifier, the output terminal of the operational amplifier is connected with the gate of the control switch, and the output voltage of the operational amplifier is used to control the on-off state of the control switch; and a voltage stabilizing circuit, the voltage stabilizing circuit is connected with the operational amplifier in parallel, the voltage stabilizing circuit receives a control signal to control the output voltage of the operational amplifier; the control circuit controls the on-off state of the control switch to control the current size of the constant current source circuit.

[0015] The voltage stabilizing circuit comprises a first voltage stabilizing circuit and a second voltage stabilizing circuit, the first voltage stabilizing circuit and the second voltage stabilizing circuit are connected with the operational amplifier in parallel, the first voltage stabilizing circuit and the second voltage stabilizing circuit are connected with the output end and the reverse input end of the operational amplifier respectively; the conduction voltage of the first voltage stabilizing circuit is higher than the conduction voltage of the second voltage stabilizing circuit; when the control signal received by the voltage stabilizing circuit is a conduction signal, the second voltage stabilizing circuit is controlled to be disconnected, and the output voltage of the operational amplifier is controlled to be the conduction voltage of the first voltage stabilizing circuit, or when the control signal received by the voltage stabilizing circuit is a disconnection signal, the second voltage stabilizing circuit is controlled to be connected, and the output voltage of the operational amplifier is controlled to be the conduction voltage of the second voltage stabilizing circuit.

[0016] The first voltage stabilizing circuit comprises a first voltage stabilizing element, the second voltage stabilizing circuit comprises a second voltage stabilizing element, a first switch and a second switch, the conduction voltage of the first voltage stabilizing element is higher than the conduction voltage of the second voltage stabilizing element; the first switch and the second switch are transistors; the second voltage stabilizing element is connected with the drain of the first switch and the drain of the second switch in series, the source of the first switch is connected with the reverse input end of the operational amplifier, and the source of the second switch is grounded; the gate of the first switch and the gate of the second switch receive a disconnection signal, the first switch is controlled to be connected, and the second switch is controlled to be connected, so that the second voltage stabilizing circuit reaches the conduction current of the second voltage stabilizing element.

[0017] Different from the prior art, the control circuit and the constant current source circuit provided by the application receive a control signal through a voltage stabilizing circuit and an operational amplifier, control the output voltage of the operational amplifier, and thus control the conduction state of the control switch, the structure of the control circuit is simple, the control circuit can control the conduction state of the control switch, control the size of the current flowing through the control switch, prevent current overshoot, protect the performance of the load, prolong the service life, improve the stability and safety of the circuit, and is conducive to reducing the maintenance cost of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of an embodiment of the control circuit of the application;

[0019] Figure 2 is a structural schematic diagram of another embodiment of the control circuit of the application;

[0020] Figure 3 is a structural schematic diagram of another embodiment of the monitoring circuit of the control switch of the application;

[0021] Figure 4 is a structural schematic diagram of another embodiment of the monitoring circuit of the control switch of the application;

[0022] Figure 5 is a structural schematic diagram of another embodiment of the control circuit of the application;

[0023] Figure 6 is a structural schematic diagram of an embodiment of a constant current source circuit of the present application;

[0024] Figure 7 is a structural schematic diagram of another embodiment of a constant current source circuit of the present application;

[0025] Figure 8 is a structural schematic diagram of still another embodiment of a constant current source circuit of the present application. DETAILED DESCRIPTION

[0026] The scheme of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0027] All the structural schematic diagrams of control circuits and constant current source circuits of the present application are logical diagrams of circuits, and the specific connection structure is referred to the structure of actual production. In the following description, specific details such as specific system structure, interface, technology, etc. are presented for the purpose of thorough understanding of the present application, but not for limiting the present application.

[0028] The present application first provides a control circuit, wherein the control circuit of the present application can control the on-off state of its control switch, has simple structure, can control the on-off state of its control switch, control the size of current flowing through the control switch, prevent current overshoot, protect the performance of the load, prolong the service life, and improve the stability and safety of the circuit.

[0029] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of an embodiment of a control circuit of the present application.

[0030] The control circuit 10 comprises: a control switch 11, the control switch 11 is connected between the negative electrode of the power supply 22 and the load 23, and the control switch 11 is a transistor; an operational amplifier 12, the output end of the operational amplifier 12 is connected to the gate of the control switch 11, and the output voltage of the operational amplifier 12 is used to control the on-off state of the control switch 11; and a voltage stabilizing circuit 13, the voltage stabilizing circuit 13 is connected to the operational amplifier 12 in parallel, the voltage stabilizing circuit 13 receives a control signal, and controls the output voltage of the operational amplifier 12.

[0031] When a given reference voltage is applied to the positive input terminal of the operational amplifier 12, the output voltage of the operational amplifier 12 is controlled by the parallel-connected voltage stabilizing circuit 13. When the on voltage of the voltage stabilizing circuit 13 is less than the reference voltage, the output voltage is clamped at the on voltage of the voltage stabilizing circuit 13 and changes with the on voltage of the voltage stabilizing circuit 13 until the on voltage of the voltage stabilizing circuit 13 approaches the reference voltage. In a specific embodiment, the reference voltage applied to the positive input terminal of the operational amplifier 12 is 5V, the on voltage of the first voltage stabilizing circuit 131 is 7.5V, and the on voltage of the second voltage stabilizing circuit 132 is 3.5V. In other embodiments, the on voltage of the first voltage stabilizing circuit 131 is equal to or greater than the reference voltage, and the reference voltage is greater than the on voltage of the second voltage stabilizing circuit 132.

[0032] The control switch 11 can be a transistor controlled by a positive voltage. In a specific embodiment, the control switch 11 is an N-type field effect transistor. The control switch 11 has a parasitic capacitor between the gate and the drain. The output voltage applied by the operational amplifier 12 is used to charge the parasitic capacitor. Therefore, when the voltage at the gate is greater than the threshold voltage, the charging process of the capacitor requires a certain amount of time, which results in a time delay in the process of increasing the voltage of the voltage stabilizing circuit 13 from a certain voltage to the drive voltage corresponding to the current. As the voltage at the drain increases, the effective channel length of the N-type field effect transistor decreases, thereby controlling the current at the drain. In other embodiments, the control switch 11 can be an insulated gate bipolar transistor or a PNP transistor.

[0033] The voltage stabilizing circuit 13 can be a circuit composed of voltage stabilizers or electronic components. In a specific embodiment, the voltage stabilizing circuit 13 includes a voltage stabilizing diode. The voltage stabilizing diode has the characteristic that the voltage remains essentially unchanged while the current changes in a large range through the reverse breakdown state of the voltage stabilizing diode. In other embodiments, the voltage stabilizing circuit 13 can be formed by a resistor-capacitor circuit or a proportional-integral circuit, and the voltage stabilizing can be performed by a voltage stabilizer or a voltage regulator.

[0034] The control signal can be an electrical signal, such as a voltage signal. The control signal is used to control the on voltage of the voltage stabilizing circuit 13, thereby controlling the output voltage of the operational amplifier 12 and the current flowing through the control switch 11.

[0035] Please refer to Figure 2 , Figure 2 which is a structural schematic diagram of another embodiment of the control circuit.

[0036] The control circuit 10 comprises: a control switch 11 connected between the negative pole of the power supply 22 and the load 23, the control switch 11 being a transistor; an operational amplifier 12, the output end of the operational amplifier 12 being connected to the gate of the control switch 11, and the output voltage of the operational amplifier 12 being used to control the on-off state of the control switch 11; and a voltage stabilizing circuit 13, the voltage stabilizing circuit 13 being connected in parallel with the operational amplifier 12, and the voltage stabilizing circuit 13 receiving a control signal and controlling the output voltage of the operational amplifier 12.

[0037] When there is a given reference voltage at the positive input end of the operational amplifier 12, the output voltage of the operational amplifier 12 is controlled by the parallel voltage stabilizing circuit 13, and when the on-voltage of the voltage stabilizing circuit 13 is less than the reference voltage, the voltage at the output end is clamped at the on-voltage of the voltage stabilizing circuit 13 and changes with the on-voltage of the voltage stabilizing circuit 13 until the on-voltage approaches the size of the reference voltage. In a specific embodiment, the size of the reference voltage at the positive input end of the operational amplifier 12 is 5V, the on-voltage of the first voltage stabilizing circuit 131 is 7.5V, and the on-voltage of the second voltage stabilizing circuit 132 is 3.5V. In other embodiments, as long as the on-voltage of the first voltage stabilizing circuit 131 is equal to or greater than the reference voltage and the reference voltage is greater than the on-voltage of the second voltage stabilizing circuit 132, the requirements are met.

[0038] The control switch 11 can be a transistor controlled by a positive voltage, and in a specific embodiment, the control switch 11 is an N-type field effect transistor. There is a parasitic capacitor between the gate and the drain of the control switch 11, and the output voltage applied by the operational amplifier 12 is a charging process for the parasitic capacitor. Therefore, when the voltage at the gate is higher than the threshold voltage, the charging process of the capacitor needs a certain time, which results in that the time required for the voltage stabilizing circuit 13 to rise from one voltage to the driving voltage corresponding to the current increases with the increase of the voltage at the drain, and the effective channel length of the N-type field effect transistor is shortened, thereby controlling the current at the drain. In other embodiments, it can also be an insulated gate bipolar transistor, a PNP transistor, or other components meeting the requirements.

[0039] The voltage stabilizing circuit 13 can be a circuit composed of voltage stabilizers or voltage stabilizing components. In a specific embodiment, the voltage stabilizing circuit 13 includes a voltage stabilizing diode, which has the characteristic that the current can change in a large range while the voltage remains basically unchanged in the reverse breakdown state of the voltage stabilizing diode, thereby playing a voltage stabilizing role. In other embodiments, the voltage stabilizing circuit 13 can be formed by a resistor-capacitor circuit, a proportional-integral circuit, a voltage stabilizer, or a voltage regulator.

[0040] In a specific embodiment, the voltage stabilizing circuit 13 comprises a first voltage stabilizing circuit 131 and a second voltage stabilizing circuit 132, which are connected in parallel with the operational amplifier 12, and the first voltage stabilizing circuit 131 and the second voltage stabilizing circuit 132 are connected to the output terminal and the reverse input terminal of the operational amplifier 12 respectively; the voltage stabilizing circuit 13 controls the on and off of the second voltage stabilizing circuit 132 according to the control signal, and controls the output voltage of the operational amplifier 12.

[0041] In a specific embodiment, the voltage stabilizing circuit 13 is provided with a voltage stabilizing diode circuit, which is connected in parallel to the output terminal and the reverse input terminal of the operational amplifier 12, and when the output voltage exceeds the stable voltage of the voltage stabilizing diode, the voltage stabilizing diode will be turned on, thereby limiting the increase of the output voltage, and ensuring that the output voltage of the output terminal will not exceed the on voltage of the voltage stabilizing diode.

[0042] In other embodiments, the voltage stabilizing circuit 13 can also be a resistance voltage dividing network composed of the first voltage stabilizing circuit 131 and the second voltage stabilizing circuit 132, which obtains a voltage greater than the reference voltage of the forward input terminal and applies it to the reverse input terminal of the operational amplifier 12, so that the output voltage of the operational amplifier 12 is switched by the control signal to control the output voltage of the output terminal, or the output voltage of the operational amplifier 12 is fed back to the reverse input terminal of the operational amplifier 12 by the first voltage stabilizing circuit 131 or the second voltage stabilizing circuit 132 to form a negative feedback mechanism, and when the output voltage rises above the set maximum value, the gain of the operational amplifier 12 is reduced by negative feedback, thereby reducing the output voltage.

[0043] The control signal can be an electrical signal, and in one case, it is a voltage signal, which controls the switching of the on voltage of the voltage stabilizing circuit 13, and controls the output voltage of the operational amplifier 12, thereby controlling the current flowing through the control switch 11.

[0044] In a specific embodiment, the on voltage of the first voltage stabilizing circuit 131 is higher than the on voltage of the second voltage stabilizing circuit 132; when the control signal received by the voltage stabilizing circuit 13 is an on signal, the second voltage stabilizing circuit 132 is controlled to be turned off, and the output voltage of the operational amplifier 12 is controlled to be the on voltage of the first voltage stabilizing circuit 131, or when the control signal received by the voltage stabilizing circuit 13 is an off signal, the second voltage stabilizing circuit 132 is controlled to be turned on, and the output voltage of the operational amplifier 12 is controlled to be the on voltage of the second voltage stabilizing circuit 132.

[0045] The second voltage stabilizing circuit 132 is controlled by the control signal. When the second voltage stabilizing circuit 132 is turned on, the output voltage of the operational amplifier 12 is clamped at the turn-on voltage of the second voltage stabilizing circuit 132. Since the turn-on voltage of the parallel circuit is lower than the turn-on voltage of the first voltage stabilizing circuit 131, only the second voltage stabilizing circuit 132 is turned on in the voltage stabilizing circuit 13. The output voltage of the operational amplifier 12 is lower than the threshold voltage of the control switch 11, or the voltage is just the voltage at which the control switch 11 is in the non-saturation region. When the second voltage stabilizing circuit 132 is turned off, the output voltage of the operational amplifier 12 is the reference voltage of the positive input terminal. At this time, the current in the voltage stabilizing circuit 13 is sufficient to turn on the first voltage stabilizing circuit 131, and only the first voltage stabilizing circuit 131 is turned on. The output voltage of the operational amplifier 12 is clamped at the turn-on voltage of the first voltage stabilizing circuit 131, and the threshold voltage of the control switch 11 is satisfied. The control switch 11 is still in the non-saturation region.

[0046] At the moment when the control signal is switched on, the output voltage of the operational amplifier 12 is limited by the second voltage stabilizing diode with a low turn-on voltage. Since the operational amplifier 12 has a certain voltage swing rate, the output voltage of the operational amplifier 12 needs time to rise from the turn-on voltage of the second voltage stabilizing circuit to the threshold voltage of the control switch 11. The voltage at the gate of the control switch 11 in the non-saturation region is low, which limits the current of the load 23 at this time, and thus the current overshoot cannot be generated.

[0047] Without the second voltage stabilizing circuit 132, the output voltage of the operational amplifier 12 is controlled by the first voltage stabilizing circuit 131 with a high turn-on voltage. At this time, the voltage at the gate of the control switch 11 is high, and thus the current overshoot is easily generated at the moment when the control signal is switched on, which affects the load 23.

[0048] After the control signal is switched on, the output voltage of the operational amplifier 12 rises from the low turn-on voltage of the second voltage stabilizing circuit 132 to the reference voltage of the positive input terminal, or rises from the low turn-on voltage of the second voltage stabilizing circuit to the threshold voltage of the control switch 11. The voltage at the gate does not rise from zero voltage, which reduces the response time and greatly improves the rising speed of the current. In a specific embodiment, the response time can reach about 10 microseconds.

[0049] Please refer to Figure 3 , Figure 3 which is a structural schematic diagram of another embodiment of the control circuit.

[0050] In a specific embodiment, the first voltage stabilizing circuit 131 comprises a first voltage stabilizing element 1311, the second voltage stabilizing circuit 132 comprises a second voltage stabilizing element 1321, a first switch 1411 and a second switch 1412, the on voltage of the first voltage stabilizing element 1311 is higher than the on voltage of the second voltage stabilizing element 1321; the first switch 1411 and the second switch 1412 are transistors; the second voltage stabilizing element 1321 is connected in series with the drain of the first switch 1411 and the drain of the second switch 1412, the source of the first switch 1411 is connected to the inverting input of the operational amplifier 12, and the source of the second switch 1412 is grounded; the gate of the first switch 1411 and the gate of the second switch 1412 receive a control signal which is an off signal, the first switch 1411 turns on the second voltage stabilizing circuit 132, and the second switch 1412 turns on to make the second voltage stabilizing circuit 132 reach the on current of the second voltage stabilizing element 1321.

[0051] The first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can be elements for limiting the voltage of the voltage stabilizing circuit 13. In a specific embodiment, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can be voltage stabilizing diodes, which have the characteristic that the voltage is basically unchanged while the current can vary in a large range through the reverse breakdown state of the voltage stabilizing diodes. In other embodiments, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can also be composed of resistors and capacitors, or voltage stabilizers or voltage regulators, etc.

[0052] In a specific embodiment, the first switch 1411 and the second switch 1412 can be transistors which receive an electrical signal to control the on state. In a specific embodiment, the control switch 11 is an N-type field effect transistor, when the control signal is off, i.e. low level, the gate of the first switch 1411 and the gate of the second switch 1412 are controlled to be high level through a level conversion element, the second voltage stabilizing circuit 132 is turned on, and vice versa, when the control signal is on, i.e. high level, the gate of the first switch 1411 and the gate of the second switch 1412 are controlled to be low level through a level conversion element, the second voltage stabilizing circuit 132 is turned off. The source of the second switch 1412 is grounded in parallel with the first switch 1411, so that when the inverting input of the operational amplifier 12 or the first switch 1411 is connected in series with a high resistance resistor, the second voltage stabilizing circuit 132 reaches the on current of the second voltage stabilizing element 1321 through the grounding of the second switch 1412.

[0053] In other embodiments, the required components can also be P-type field effect transistors, insulated gate bipolar transistors, triodes, relays, etc. For example, when the control switch 11 is a P-type field effect transistor, the level conversion element is not required. When the control signal is off (low level), the gate of the first switch 1411 and the second switch 1412 is directly controlled to be low level, and the second voltage stabilizing circuit 132 is turned on. Conversely, when the control signal is on (high level), the gate of the first switch 1411 and the second switch 1412 is directly controlled to be high level, and the second voltage stabilizing circuit 132 is turned off.

[0054] Figure 4 is a structural schematic diagram of another embodiment of the monitoring circuit of the control switch of the present application;

[0055] In one embodiment, the first voltage stabilizing circuit 131 includes a first voltage stabilizing element 1311, the second voltage stabilizing circuit 132 includes a second voltage stabilizing element 1321, a first switch 1411 and a second switch 1412, the on voltage of the first voltage stabilizing element 1311 is higher than the on voltage of the second voltage stabilizing element 1321, the first switch 1411 and the second switch 1412 are transistors, the second voltage stabilizing element 1321 is connected in series with the drain of the first switch 1411 and the drain of the second switch 1412, the source of the first switch 1411 is connected to the inverting input terminal of the operational amplifier 12, and the source of the second switch 1412 is connected to ground. The gate of the first switch 1411 and the gate of the second switch 1412 receive the control signal as an off signal, the first switch 1411 turns on the second voltage stabilizing circuit 132, and the second switch 1412 turns on to make the second voltage stabilizing circuit 132 reach the on current of the second voltage stabilizing element 1321.

[0056] The second voltage stabilizing circuit 132 further includes a third switch 1413, the third switch 1413 is a transistor, the drain of the third switch 1413 is connected to the gate of the first switch 1411 and the gate of the second switch 1412, the gate of the third switch 1413 receives the control signal as an on signal, and the third switch 1413 is controlled to be off to turn on the first switch 1411 and the second switch 1412, or the gate of the third switch 1413 receives the control signal as an off signal, and the third switch 1413 is controlled to be on to turn off the first switch 1411 and the second switch 1412.

[0057] Specifically, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can be elements for limiting the voltage of the voltage stabilizing circuit 13. In a specific embodiment, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can be zener diodes. Through the reverse breakdown state of the zener diodes, the current can vary in a large range while the voltage is basically unchanged, thus playing a voltage stabilizing role. In other embodiments, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can also be composed of resistors and capacitors, or be voltage stabilizers or voltage regulators, etc.

[0058] The first switch 1411, the second switch 1412 and the third switch 1413 can be transistors controlled to be turned on by receiving an electrical signal. In a specific embodiment, the control switch 11 is an N-type field effect transistor. The gate of the first switch 1411 and the gate of the second switch 1412 are also connected to the adjusting voltage, respectively, to provide the voltage for the first switch 1411 and the second switch 1412. The adjusting voltage is also connected to the drain of the third switch 1413, and the source of the third switch 1413 is grounded. When the third switch 1413 is turned on, the adjusting voltage is grounded.

[0059] When the control signal is off, i.e., low, the third switch 1413 is controlled to be turned off, the adjusting voltage provides a high-level voltage for the gates of the first switch 1411 and the second switch 1412, and the second voltage stabilizing circuit 132 is controlled to be turned on. Conversely, when the control signal is on, i.e., high, the third switch 1413 is turned on, the adjusting voltage is grounded, and the gates of the first switch 1411 and the second switch 1412 are controlled to be low, and the second voltage stabilizing circuit 132 is controlled to be turned off.

[0060] In other embodiments, the first switch 1411 and the second switch 1412 can also be P-type field effect transistors, insulated gate bipolar transistors, triodes or relays, etc. that meet the requirements. For example, when the control switch 11 is a P-type field effect transistor, a level conversion element is not needed. When the control signal is off, i.e., low, the gates of the first switch 1411 and the second switch 1412 are directly controlled to be low, the second voltage stabilizing circuit 132 is controlled to be turned on. Conversely, when the control signal is on, i.e., high, the gates of the first switch 1411 and the second switch 1412 are directly controlled to be high, and the second voltage stabilizing circuit 132 is controlled to be turned off.

[0061] Please refer to Figure 5 , Figure 5 which is a structural schematic diagram of another embodiment of the control circuit of the application.

[0062] The control circuit 10 comprises: a control switch 11 connected between the negative pole of the power supply 22 and the load 23, the control switch 11 being a transistor; an operational amplifier 12, the output of the operational amplifier 12 being connected to the gate of the control switch 11, and the output voltage of the operational amplifier 12 being used to control the on-off state of the control switch 11; and a voltage stabilizing circuit 13 connected in parallel with the operational amplifier 12, the voltage stabilizing circuit 13 receiving a control signal and controlling the output voltage of the operational amplifier 12.

[0063] The structure of the voltage stabilizing circuit 13 will be described in detail below with reference to the structure of the control circuit embodiment or another embodiment of the application. Figure 1 Figure 2 The structure of the voltage stabilizing circuit 13 will be described in detail below with reference to the structure of the control circuit embodiment or another embodiment of the application.

[0064] In an alternative embodiment, the control circuit 10 comprises: a control switch feedback circuit 151 connected to the inverting input of the operational amplifier 12 and receiving the voltage of the circuit in which the control switch 11 is located; and the operational amplifier 12 collects the voltage of the circuit when the voltage exceeds a threshold voltage and sends a control signal to control the off state of the control switch 11.

[0065] The output voltage of the operational amplifier 12 is fed back to the inverting input of the operational amplifier 12 through a negative feedback mechanism. When the output voltage rises above a set maximum value, the negative feedback reduces the gain of the operational amplifier 12, thereby reducing the output voltage and keeping it below the maximum voltage limit.

[0066] Since a large resistor is provided on the control switch feedback circuit 151, when the control signal is off, the voltage output by the operational amplifier 12 is too small to flow through the second voltage stabilizing circuit 132 due to the presence of the large resistor, and the first switch 1411 is turned on. The current flowing through the second voltage stabilizing circuit 132 is smaller than the conduction current of the second voltage stabilizing element 1321, so the second voltage stabilizing element 1321 cannot be saturated and turned on, and the voltage required to clamp the output voltage of the operational amplifier 12 cannot be reached. Therefore, the second switch 1412 is provided, and the second switch 1412 is connected in series with a resistor (not shown in the figure). The second switch 1412 is turned on, and the resistor is connected in parallel with the large resistance resistor (not shown in the figure) on the control switch feedback circuit 151, so that the current flowing through the second voltage stabilizing circuit 132 at least partially passes through the second switch 1412 and the resistor and then is grounded, thereby enabling the second voltage stabilizing circuit 132 to reach the conduction current of the second voltage stabilizing element 1321.

[0067] The control circuit 10 comprises: an operational amplifier feedback circuit 152 connected in parallel with the operational amplifier 12, the operational amplifier feedback circuit 152 comprising a feedback capacitor and a feedback resistor, and controlling the rate of change of the output voltage of the operational amplifier 12.

[0068] ​The operational amplifier feedback circuit 152, which is a series connection of a capacitor and a resistor, can form a proportional-integral adjustment for the operational amplifier 12, and control the rate of change of the output voltage of the operational amplifier, so that the output voltage of the operational amplifier 12 can smoothly conduct the current of the control switch 11 during the process of rising from the conduction voltage of the second voltage regulator circuit 132 to the conduction voltage of the first voltage regulator circuit 131, thereby preventing current overshoot in the load 23.

[0069] The control circuit provided in the above embodiment receives a control signal through a voltage stabilizing circuit and an operational amplifier, and uses the voltage stabilizing circuit to control the output voltage of the operational amplifier, thereby controlling the conduction state of its control switch. The control circuit has a simple structure and can control the conduction state of its control switch and the current flowing through the control switch. A control switch feedback circuit and an operational amplifier feedback circuit are provided to prevent current overshoot, protect load performance, extend service life, improve circuit stability and safety, and help reduce circuit maintenance costs.

[0070] The present application also provides a constant current source circuit. The constant current source circuit of the present application controls its control circuit through a control signal to prevent the load of the constant current source circuit from being subjected to voltage overshoot when it is turned on, thereby protecting the load and extending the service life of the load.

[0071] See also Figure 6 , Figure 6 It is a structural schematic diagram of an embodiment of a constant current source circuit of the present application.

[0072] The constant current source circuit 20 includes a drive switch 21 and a control circuit 10. The drive switch 21 is arranged between the positive terminal of the power supply 22 and the positive terminal of the load 23. The drive switch 21 receives a control signal and turns on or off the drive switch 21 in response to the control signal. The control circuit 10 controls the current of the constant current source circuit 20 by controlling the conduction state of the control switch 11.

[0073] In the constant current source circuit 20, the on and off of the constant current source circuit 20 is controlled by the driving switch 21, and the magnitude of the current conducted by the constant current source circuit 20 is controlled by the control switch 11. In particular, at the moment when the driving switch 21 is turned on, the current overshoot caused by the rapid response of the power supply 22 is prevented, which affects or damages the load 23, thereby protecting the constant current source circuit 20. In other embodiments, a separate control switch 11 can also be provided, and the control current can also be responsible for controlling the conduction of the power supply 22 of the constant current source circuit 20.

[0074] The control signal may be an electrical signal. In a specific embodiment, the control signal is a voltage signal, which controls the driving switch 21 and its control circuit 10 through voltage control, thereby controlling the current flowing through the control switch 11 .

[0075] The control circuit 10 comprises: a control switch 11 connected between the negative pole of the power supply 22 and the load 23, the control switch 11 being a transistor; an operational amplifier 12, the output of the operational amplifier 12 being connected to the gate of the control switch 11, the output voltage of the operational amplifier 12 being used to control the on-off state of the control switch 11; and a voltage stabilizing circuit 13, the voltage stabilizing circuit 13 being connected in parallel with the operational amplifier 12, the voltage stabilizing circuit 13 receiving a control signal and controlling the output voltage of the operational amplifier 12.

[0076] When there is a given reference voltage at the positive input of the operational amplifier 12, the output voltage of the operational amplifier 12 is controlled by the parallel voltage stabilizing circuit 13, and when the on voltage of the voltage stabilizing circuit 13 is less than the reference voltage, the output voltage is clamped at the on voltage of the voltage stabilizing circuit 13 and changes with the on voltage of the voltage stabilizing circuit 13 until the on voltage of the voltage stabilizing circuit 13 approaches the reference voltage. In a specific embodiment, the reference voltage at the positive input of the operational amplifier 12 is 5V, the on voltage of the first voltage stabilizing circuit 131 is 7.5V, and the on voltage of the second voltage stabilizing circuit 132 is 3.5V, and in other embodiments, as long as the on voltage of the first voltage stabilizing circuit 131 is equal to or greater than the reference voltage and the reference voltage is greater than the on voltage of the second voltage stabilizing circuit 132.

[0077] The control switch 11 can be a transistor controlled by a positive voltage, and in a specific embodiment, the control switch 11 is an N-type field effect transistor, there is a parasitic capacitor between the gate and the drain of the control switch 11, the output voltage of the operational amplifier 12 is used to charge the parasitic capacitor, and therefore when the gate voltage is above the threshold voltage, the charging process of the capacitor requires a certain time, which results in that the time required for the voltage stabilizing circuit 13 to rise from one voltage to the drive voltage corresponding to the current increases with the increase of the drain voltage, the effective channel length of the N-type field effect transistor is shortened, and thus the current flowing through the drain is controlled. In other embodiments, it can also be an insulated gate bipolar transistor, a PNP transistor, or other components that meet the requirements.

[0078] The voltage stabilizing circuit 13 can be a circuit composed of voltage stabilizers or components, and in a specific embodiment, the voltage stabilizing circuit 13 includes a voltage stabilizing diode, which has the characteristic that the current can change in a large range while the voltage remains basically unchanged in the reverse breakdown state of the voltage stabilizing diode, and thus plays a role in voltage stabilization. In other embodiments, the voltage stabilizing circuit 13 can also be formed by a resistor-capacitor circuit, a proportional-integral circuit, a voltage stabilizer, or a voltage regulator.

[0079] In a specific embodiment, the on voltage of the voltage stabilizing circuit 13 is switched by voltage control, and thus the output voltage of the operational amplifier 12 is controlled, and the current flowing through the control switch 11 is controlled.

[0080] Please refer to Figure 7 , Figure 7 is a schematic diagram of another embodiment of the constant current source circuit.

[0081] The constant current source circuit 20 comprises a driving switch 21 and a control circuit 10. The driving switch 21 is arranged between the positive electrode of the power supply 22 and the positive terminal of the load 23. The driving switch 21 receives a control signal and turns on or off in response to the control signal. The control circuit 10 controls the current of the constant current source circuit 20 by controlling the on-off state of the control switch 11.

[0082] In the constant current source circuit 20, the on-off state of the constant current source circuit 20 is controlled by the driving switch 21, and the current of the constant current source circuit 20 is controlled by the control switch 11. In particular, at the moment when the driving switch 21 is turned on, the current overshoot caused by the rapid response of the power supply 22 is prevented, thereby protecting the constant current source circuit 20. In other embodiments, the control switch 11 can be arranged separately, and the control current can be responsible for controlling the on-off state of the constant current source circuit 20.

[0083] The control signal can be an electrical signal. In a specific embodiment, the control signal is a voltage signal, which controls the driving switch 21 and the control circuit 10 to control the current flowing through the control switch 11.

[0084] The control circuit 10 comprises a control switch 11, a transistor, and an operational amplifier 12. The control switch 11 is connected between the negative electrode of the power supply 22 and the load 23. The output terminal of the operational amplifier 12 is connected to the gate of the control switch 11. The output voltage of the operational amplifier 12 is used to control the on-off state of the control switch 11. A voltage stabilizing circuit 13 is connected in parallel with the operational amplifier 12. The voltage stabilizing circuit 13 receives the control signal and controls the output voltage of the operational amplifier 12.

[0085] When there is a given reference voltage at the positive input terminal of the operational amplifier 12, the output voltage of the operational amplifier 12 is controlled by the parallel voltage stabilizing circuit 13. When the on voltage of the voltage stabilizing circuit 13 is less than the reference voltage, the output voltage is clamped at the on voltage of the voltage stabilizing circuit 13 and changes with the on voltage of the voltage stabilizing circuit 13 until it approaches the size of the reference voltage. In a specific embodiment, the reference voltage at the positive input terminal of the operational amplifier 12 is 5V, the on voltage of the first voltage stabilizing circuit 131 is 7.5V, and the on voltage of the second voltage stabilizing circuit 132 is 3.5V. In other embodiments, as long as the on voltage of the first voltage stabilizing circuit 131 is equal to or greater than the reference voltage and the reference voltage is greater than the on voltage of the second voltage stabilizing circuit 132.

[0086] The control switch 11 can be a transistor controlled by a positive voltage, and in a specific embodiment, the control switch 11 is an N-type field effect transistor. There is a parasitic capacitor between the gate and the drain of the control switch 11. The output voltage applied by the operational amplifier 12 is a process of charging the parasitic capacitor. Therefore, when the voltage at the gate is higher than the threshold voltage, the charging process of the capacitor needs a certain time, which leads to the time required for the voltage from the voltage regulator 13 to rise to the driving voltage corresponding to the current. As the voltage at the drain rises, the effective channel length of the N-type field effect transistor is shortened, thereby controlling the current at the drain. In other embodiments, the control switch 11 can also be an insulated gate bipolar transistor, a PNP transistor, or other components that meet the requirements.

[0087] The voltage regulator 13 can be a circuit composed of a voltage regulator or components. In a specific embodiment, the voltage regulator 13 includes a voltage regulator diode. The voltage regulator diode has the characteristic that the voltage is basically unchanged when the current changes in a large range through the reverse breakdown state of the voltage regulator diode, thereby playing a role in voltage stabilization. In other embodiments, the voltage regulator 13 can be formed by a resistor-capacitor circuit, a proportional-integral circuit, a voltage regulator, or a voltage regulator.

[0088] In a specific embodiment, the switching of the on-voltage of the voltage regulator 13 is controlled by the voltage, thereby controlling the output voltage of the operational amplifier 12 and the current flowing through the control switch 11.

[0089] In an alternative embodiment, the voltage regulator 13 includes a first voltage regulator 131 and a second voltage regulator 132. The first voltage regulator 131 and the second voltage regulator 132 are connected in parallel with the operational amplifier 12. The first voltage regulator 131 and the second voltage regulator 132 are connected to the output terminal and the reverse input terminal of the operational amplifier 12, respectively. The on-voltage of the first voltage regulator 131 is higher than the on-voltage of the second voltage regulator 132. When the control signal received by the voltage regulator 13 is a turn-on signal, the second voltage regulator 132 is controlled to be turned off, and the output voltage of the operational amplifier 12 is controlled to be the on-voltage of the first voltage regulator 131. Alternatively, when the control signal received by the voltage regulator 13 is a turn-off signal, the second voltage regulator 132 is controlled to be turned on, and the output voltage of the operational amplifier 12 is controlled to be the on-voltage of the second voltage regulator 132.

[0090] In a specific embodiment, the voltage regulator 13 is a circuit provided with a voltage regulator diode. When the output voltage exceeds the stable voltage of the voltage regulator diode, the voltage regulator diode is turned on, thereby limiting the increase of the output voltage and ensuring that the output voltage at the output terminal does not exceed the on-voltage of the voltage regulator diode.

[0091] In other embodiments, the voltage stabilizing circuit 13 can also be a resistive voltage divider network composed of a first voltage stabilizing circuit 131 and a second voltage stabilizing circuit 132, obtaining a voltage greater than the reference voltage of the positive input terminal, applied to the negative input terminal of the operational amplifier 12, so that the output voltage of the operational amplifier 12 is controlled by the control signal switching the voltage applied to the negative input terminal of the operational amplifier 12, or by using the first voltage stabilizing circuit 131 or the second voltage stabilizing circuit 132 to form a negative feedback mechanism by feeding back the output voltage of the operational amplifier 12 to its negative input terminal, so that when the output voltage rises above a set maximum value, the gain of the operational amplifier 12 is reduced by negative feedback, thereby reducing the output voltage.

[0092] The control signal can be an electrical signal, in this case a voltage signal, which controls the switching of the on-voltage of the voltage stabilizing circuit 13 to control the output voltage of the operational amplifier 12, thereby controlling the current flowing through the control switch 11.

[0093] By controlling the on or off of the second voltage stabilizing circuit 132 through the control signal, when the second voltage stabilizing circuit 132 is on, the output voltage of the operational amplifier 12 is clamped at the on-voltage of the second voltage stabilizing circuit 132, and since the on-voltage of the parallel circuit is not as high as the on-voltage of the first voltage stabilizing circuit 131, only the second voltage stabilizing circuit 132 is on in the voltage stabilizing circuit 13 at this time, so that the output voltage of the operational amplifier 12 received by the control switch 11 at this time is less than the threshold voltage of the control switch 11, or it can be the voltage at which the control switch 11 is just in the non-saturation region; when the second voltage stabilizing circuit 132 is off, the output voltage of the operational amplifier 12 is the reference voltage of the positive input terminal, at this time the current in the voltage stabilizing circuit 13 satisfies the on-voltage of the first voltage stabilizing circuit 131 and only the first voltage stabilizing circuit 131 is on, the output voltage of the operational amplifier 12 is clamped at the on-voltage of the first voltage stabilizing circuit 131, and the threshold voltage of the control switch 11 is also satisfied, so that the control switch 11 is still in the non-saturation region.

[0094] At the moment when the control signal switches to on, due to the existence of the second voltage stabilizing circuit 13 with low on-voltage, the output voltage of the operational amplifier 12 is limited. Because the operational amplifier 12 has a certain voltage droop rate, the output voltage of the operational amplifier 12 needs time to climb from the on-voltage of the second voltage stabilizing circuit 13 to the threshold voltage of the control switch 11, so that the voltage of the gate of the control switch 11 in the unsaturated state is low, which limits the current of the load 23 at this time, so that the current overshoot cannot be generated. Without the existence of the second voltage stabilizing circuit 13, the output voltage of the operational amplifier 12 is controlled by the first voltage stabilizing circuit 13 with high on-voltage at this time, so that the voltage of the gate of the control switch 11 is high, and thus the moment when the control signal switches to on is easy to generate an overshoot current, which affects the load 23.

[0095] Moreover, after the control signal switches to on, because the output voltage of the operational amplifier 12 climbs from the on-voltage of the second voltage stabilizing circuit 13 to the reference voltage of the positive input terminal, or from the on-voltage of the second voltage stabilizing circuit 13 to the threshold voltage of the control switch 11, and the voltage of the gate does not start to climb from zero voltage, the response time is reduced, thereby greatly improving the current rising speed. In a specific embodiment, the response time can reach about 10 microseconds.

[0096] Please refer to Figure 8 , Figure 8 is a structural schematic diagram of another embodiment of the constant current source circuit.

[0097] The control circuit 10 comprises: a control switch 11 connected between the negative electrode of the power supply 22 and the load 23, the control switch 11 being a transistor; an operational amplifier 12, the output end of the operational amplifier 12 being connected to the gate of the control switch 11, the output voltage of the operational amplifier 12 being used to control the on-off state of the control switch 11; and a voltage stabilizing circuit 13, the voltage stabilizing circuit 13 being connected to the operational amplifier 12 in parallel, the voltage stabilizing circuit 13 receiving a control signal and controlling the output voltage of the operational amplifier 12.

[0098] The voltage stabilizing circuit 13 comprises a first voltage stabilizing circuit 131 and a second voltage stabilizing circuit 132, the first voltage stabilizing circuit 131 and the second voltage stabilizing circuit 132 are connected in parallel with the operational amplifier 12, and the first voltage stabilizing circuit 131 and the second voltage stabilizing circuit 132 are connected to the output end and the reverse input end of the operational amplifier 12 respectively; the conduction voltage of the first voltage stabilizing circuit 131 is higher than that of the second voltage stabilizing circuit 132; when the control signal received by the voltage stabilizing circuit 13 is a conduction signal, the second voltage stabilizing circuit 132 is controlled to be turned off, and the output voltage of the operational amplifier 12 is controlled to be the conduction voltage of the first voltage stabilizing circuit 131; or when the control signal received by the voltage stabilizing circuit 13 is an off signal, the second voltage stabilizing circuit 132 is controlled to be turned on, and the output voltage of the operational amplifier 12 is controlled to be the conduction voltage of the second voltage stabilizing circuit 132.

[0099] The structure of the control circuit 10 can be described in detail with reference to the structure description of the constant current source circuit embodiment or another embodiment of the application in Figure 6 or Figure 7 The structure of the control circuit 10 can be described in detail with reference to the structure description of the constant current source circuit embodiment or another embodiment of the application in

[0100] In a specific embodiment, the first voltage stabilizing circuit 131 comprises a first voltage stabilizing element 1311, the second voltage stabilizing circuit 132 comprises a second voltage stabilizing element 1321, a first switch 1411 and a second switch 1412, the conduction voltage of the first voltage stabilizing element 1311 is higher than that of the second voltage stabilizing element 1321; the first switch 1411 and the second switch 1412 are transistors; the second voltage stabilizing element 1321 is connected in series with the drain of the first switch 1411 and the drain of the second switch 1412 respectively, the source of the first switch 1411 is connected to the reverse input end of the operational amplifier 12, and the source of the second switch 1412 is grounded; the gate of the first switch 1411 and the gate of the second switch 1412 receive an off signal of the control signal, the first switch 1411 turns on the second voltage stabilizing circuit 132, and the second switch 1412 turns on to make the second voltage stabilizing circuit 132 reach the conduction current of the second voltage stabilizing element 1321.

[0101] Specifically, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can be elements for limiting the voltage of the voltage stabilizing circuit 13. In a specific embodiment, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can be voltage stabilizing diodes, which have the characteristics that the current can change in a large range while the voltage is basically unchanged through the reverse breakdown state of the voltage stabilizing diodes, so as to play a voltage stabilizing role. In other embodiments, the first voltage stabilizing element 1311 and the second voltage stabilizing element 1321 can also be composed of resistors and capacitors, or be voltage stabilizers or voltage regulators, etc.

[0102] The first switch 1411 and the second switch 1412 can be transistors that receive electrical signals to control conduction. In a specific embodiment, the control switch 11 is an N-type field effect transistor. The gate of the first switch 1411 and the gate of the second switch 1412 are also connected to the adjustment voltage, respectively, to provide voltage for the first switch 1411 and the second switch 1412. The adjustment voltage is also connected to the drain of the third switch 1413. The source of the third switch 1413 is grounded. When the third switch 1413 is turned on, the adjustment voltage is grounded.

[0103] In a specific embodiment, the second voltage stabilizing circuit 132 further includes a third switch 1413, which is a transistor; the drain of the third switch 1413 is connected to the gate of the first switch 1411 and the gate of the second switch 1412, respectively; the gate of the third switch 1413 receives a control signal as a turn-on signal, which controls the turn-off of the third switch 1413 to turn on the first switch 1411 and the second switch 1412; or, the gate of the third switch 1413 receives a control signal as a turn-off signal, which controls the turn-on of the third switch 1413 to turn off the first switch 1411 and the second switch 1412.

[0104] The third switch 1413 can be a transistor that receives an electrical signal to control conduction. In a specific embodiment, the control switch 11 is an N-type field effect transistor. When the control signal is off, that is, at a low level, the third switch 1413 is controlled to be turned off, and the regulated voltage is used to control the gates of the first switch 1411 and the second switch 1412 to provide a high-level voltage, thereby controlling the second voltage stabilization circuit 132 to be turned on. Conversely, when the control signal is on, that is, at a high level, the third switch 1413 is turned on, grounding the regulated voltage, controlling the gates of the first switch 1411 and the second switch 1412 to be at a low level, thereby controlling the second voltage stabilization circuit 132 to be turned off.

[0105] In other embodiments, the first switch 1411 and the second switch 1412 may also be P-type field-effect transistors, insulated gate bipolar transistors, transistors, or relays, and other suitable components. For example, when the control switch 11 is a P-type field-effect transistor, no level conversion element is required. When the control signal is off, i.e., at a low level, the gates of the first switch 1411 and the second switch 1412 are directly controlled to be at a low level, thereby turning on the second voltage-stabilizing circuit 132. Conversely, when the control signal is on, i.e., at a high level, the gates of the first switch 1411 and the second switch 1412 are directly controlled to be at a high level, thereby turning off the second voltage-stabilizing circuit 132.

[0106] In other embodiments, the control circuit 10 of the constant current source circuit 20 may also be provided with a control switch feedback circuit 151 and an operational amplifier feedback circuit 152 to further control the rate of change of the output voltage of the operational amplifier 12, prevent current overshoot, and protect the performance of the load 23.

[0107] The constant current source circuit provided in the above embodiment receives a control signal through a driving switch and a control circuit, controls the on-off state of the control switch by the control circuit, the control circuit has a simple structure, and controls the current flowing through the control switch, on the basis of ensuring fast response of the power supply, effectively prevents current overshoot, protects the performance of the load, prolongs the service life, improves the stability and safety of the circuit, and is beneficial to reduce the maintenance cost of the circuit.

[0108] In several embodiments provided in the present application, it should be understood that the disclosed system and device can be implemented in other manners. Obviously, the embodiments described are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the present application. For example, the above-described device embodiment is only a schematic, for example, the division of the modules or units is only a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed mutual elements can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0109] It should be noted that if the present application has directionality indication (such as up, down, left, right, front, back, etc.), the directionality indication is only used to explain the relative position relationship, motion condition, etc. between the components in a certain posture (as shown in the drawings), if the certain posture changes, the directionality indication also changes accordingly.

[0110] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "coupling", "connecting", "connecting", "setting", "installing" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0111] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the present embodiment scheme.

[0112] In addition, the technical solutions among various embodiments can be combined with each other, but it must be based on that a person skilled in the art can realize, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0113] The above is only the implementation of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A control circuit, characterized in that: The control circuit comprises: A control switch connected between the negative electrode of the power supply and the load, wherein the control switch is a transistor; an operational amplifier, wherein an output terminal of the operational amplifier is connected to a gate of the control switch, and an output voltage of the operational amplifier is used to control an on / off state of the control switch; A voltage stabilizing circuit is connected in parallel with the operational amplifier, and the voltage stabilizing circuit receives a control signal to control the output voltage of the operational amplifier.

2. The control circuit according to claim 1, wherein: The voltage stabilizing circuit comprises: a first voltage stabilizing circuit and a second voltage stabilizing circuit, wherein the first voltage stabilizing circuit and the second voltage stabilizing circuit are connected in parallel with the operational amplifier, and the first voltage stabilizing circuit and the second voltage stabilizing circuit are respectively connected to the output terminal and the inverting input terminal of the operational amplifier; The voltage stabilizing circuit controls the on and off of the second voltage stabilizing circuit according to the control signal, thereby controlling the output voltage of the operational amplifier.

3. The control circuit according to claim 2, characterized in that: The conduction voltage of the first voltage stabilizing circuit is higher than the conduction voltage of the second voltage stabilizing circuit; When the control signal received by the voltage stabilizing circuit is a turn-on signal, the second voltage stabilizing circuit is controlled to be turned off, and the output voltage of the operational amplifier is controlled to be the turn-on voltage of the first voltage stabilizing circuit; or, when the control signal received by the voltage stabilizing circuit is a turn-off signal, the second voltage stabilizing circuit is controlled to be turned on, and the output voltage of the operational amplifier is controlled to be the turn-on voltage of the second voltage stabilizing circuit.

4. The control circuit according to claim 2 or 3, characterized in that: The first voltage stabilizing circuit includes a first voltage stabilizing element, the second voltage stabilizing circuit includes a second voltage stabilizing element, a first switch, and a second switch, wherein the turn-on voltage of the first voltage stabilizing element is higher than the turn-on voltage of the second voltage stabilizing element; The first switch and the second switch are transistors; the second voltage stabilizing element is connected in series with the drain of the first switch and the drain of the second switch respectively; the source of the first switch is connected to the inverting input terminal of the operational amplifier, and the source of the second switch is grounded; When the gates of the first switch and the second switch receive the control signal as a shut-off signal, the first switch turns on the second voltage stabilizing circuit, and the second switch turns on so that the second voltage stabilizing circuit reaches the conduction current of the second voltage stabilizing element.

5. The control circuit according to claim 4, characterized in that: The second voltage stabilizing circuit further includes a third switch, which is a transistor; a drain of the third switch is connected to the gate of the first switch and the gate of the second switch respectively; The gate of the third switch receives the control signal as a turn-on signal, controlling the turn-off of the third switch to turn on the first switch and the second switch; or The gate of the third switch receives the control signal as a turn-off signal, and controls the conduction of the third switch to turn off the first switch and the second switch.

6. The control circuit according to claim 1, wherein: The control circuit includes: a control switch feedback circuit, the control switch feedback circuit is connected to the inverting input terminal of the operational amplifier and receives the circuit voltage where the control switch is located; When the circuit voltage detected by the operational amplifier exceeds a threshold voltage, the operational amplifier sends a control signal to control the control switch to be turned off.

7. The control circuit according to claim 1, wherein: The control circuit includes an operational amplifier feedback circuit, which is connected in parallel with the operational amplifier. The operational amplifier feedback circuit includes a feedback capacitor and a feedback resistor, and controls the rate of change of the output voltage of the operational amplifier.

8. A constant current source circuit, characterized in that: The constant current source circuit comprises: A drive switch and a control circuit, wherein the drive switch is arranged between the positive terminal of the power supply and the positive terminal of the load, and the drive switch receives a control signal and turns on or off the drive switch in response to the control signal; The control circuit includes: a control switch connected between the negative electrode of the power supply and the load, the control switch being a transistor; an operational amplifier, the output end of the operational amplifier being connected to the gate of the control switch, the output voltage of the operational amplifier being used to control the on / off state of the control switch; a voltage stabilizing circuit, the voltage stabilizing circuit and the operational amplifier being connected in parallel, the voltage stabilizing circuit receiving the control signal and controlling the output voltage of the operational amplifier; The control circuit controls the current of the constant current source circuit by controlling the conduction state of the control switch.

9. The constant current source circuit according to claim 8, characterized in that: The voltage stabilizing circuit comprises: a first voltage stabilizing circuit and a second voltage stabilizing circuit, wherein the first voltage stabilizing circuit and the second voltage stabilizing circuit are connected in parallel with the operational amplifier, and the first voltage stabilizing circuit and the second voltage stabilizing circuit are respectively connected to the output terminal and the inverting input terminal of the operational amplifier; The on-voltage of the first voltage-stabilizing circuit is higher than the on-voltage of the second voltage-stabilizing circuit; when the control signal received by the voltage-stabilizing circuit is a on-signal, the second voltage-stabilizing circuit is controlled to be disconnected, and the output voltage of the operational amplifier is controlled to be the on-voltage of the first voltage-stabilizing circuit, or, when the control signal received by the voltage-stabilizing circuit is a shut-down signal, the second voltage-stabilizing circuit is controlled to be turned on, and the output voltage of the operational amplifier is controlled to be the on-voltage of the second voltage-stabilizing circuit.

10. The constant current source circuit according to claim 9, characterized in that: The first voltage stabilizing circuit includes a first voltage stabilizing element, the second voltage stabilizing circuit includes a second voltage stabilizing element, a first switch, and a second switch, wherein the turn-on voltage of the first voltage stabilizing element is higher than the turn-on voltage of the second voltage stabilizing element; The first switch and the second switch are transistors; the second voltage stabilizing element is connected in series with the drain of the first switch and the drain of the second switch respectively; the source of the first switch is connected to the inverting input terminal of the operational amplifier, and the source of the second switch is grounded; When the gates of the first switch and the second switch receive the control signal as a turn-off signal, the first switch turns on the second voltage stabilizing circuit, and the second switch turns on so that the second voltage stabilizing circuit reaches the conduction current of the second voltage stabilizing element.

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