Self-recovery constant current control circuit

Abstract

The utility model discloses a self-recovery constant current control circuit which comprises a power supply module, a current detection module and a self-recovery protection module, and the power supply module is connected with the self-recovery protection module for supplying power. The self-recovery protection module comprises a comparison circuit unit and a switch control unit, one end of the comparison circuit unit is connected with the current detection module to guarantee constant current output, and the other end of the comparison circuit unit is connected with the switch control unit to control turn-off and turn-on recovery of the power supply. Through the arrangement of the self-recovery protection module, when overcurrent occurs, the comparison circuit unit feeds back information to the switch control unit so as to control the turn-off of the power supply; and when the current returns to normal, the comparison circuit unit enables the switch control unit to drive the power supply to recover, so that the effect of self-recovery during the overcurrent fault is achieved. Manual power-off restart is not needed, the reliability of the system is improved, the situation that a user misjudges that the power supply is damaged is avoided, and meanwhile the service life of equipment can be prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of constant current output, in particular to a self-recovering constant current control circuit. Background Art

[0002] In modern electronic circuits, constant current control circuits are widely used in situations where stable current output is required. For example, they play an important role in the application of LEDs. Constant current control circuits can ensure that LEDs work under constant current, thereby ensuring their brightness and life.

[0003] However, although the existing multi-channel constant current circuit can provide constant current, it has a significant defect, that is, when an overcurrent occurs, the circuit needs to be completely powered off and restarted to resume normal operation, which not only interrupts the normal operation of the device, but also the user may mistakenly believe that the power supply is damaged, affecting the user experience and the reliability of the device. In addition, frequent power-off and restart operations may also cause additional stress on the circuit and equipment, shortening their service life. Utility Model Content

[0004] In view of the above situation, it is necessary to provide a self-recovering constant current control circuit to solve the problem that the existing constant current circuit needs to be powered off and restarted when overcurrent occurs.

[0005] To achieve the above object, the technical solution of the utility model is as follows: a self-recovering constant current control circuit, comprising: a power module, a current detection module and a self-recovering protection module, the power module and the self-recovering protection module are connected for power supply;

[0006] The self-recovery protection module includes a comparison circuit unit and a switch control unit. One end of the comparison circuit unit is connected to the current detection module to ensure the output of a constant current, and the other end of the comparison circuit unit is connected to the switch control unit to control the shutdown and start recovery of the power supply.

[0007] In the self-recovering constant current control circuit of the utility model, the comparison circuit unit includes a dual operational amplifier U1 and a field effect transistor Q1; the gate of the field effect transistor Q1 is connected to the dual operational amplifier U1, the drain of the field effect transistor Q1 is connected to the current detection module, and the source of the field effect transistor Q1 is grounded.

[0008] In the self-recovering constant current control circuit of the utility model, the switch control unit includes a driving chip U2, a switch tube Q4, a switch tube Q5 and a relay switch P1. The driving chip U2 is connected to the dual operational amplifier U1 to receive feedback information; the driving chip U2 is also connected to the switch tube Q5 to control its on and off states, and the switch tube Q5 is connected to the switch tube Q4 through the relay switch P1.

[0009] In the self-recovery constant current control circuit of the utility model, the switch control unit also includes a field effect tube Q2 and a field effect tube Q3; the gate of the field effect tube Q2 is connected to the collector of the switch tube Q5, the source of the switch tube Q2 is connected to the source of the field effect tube Q3, and the gate of the field effect tube Q3 is connected to the source.

[0010] In the self-recovery constant current control circuit of the utility model, the current detection module includes a detection resistor R3.

[0011] The self-recovering constant current control circuit of the utility model also includes a filter circuit unit; the filter circuit unit includes a resistor R7 and a capacitor R4 connected in parallel, one end of the filter circuit unit is connected to the gate of the field effect tube Q1, and the other end is connected to the source of the field effect tube Q1 and grounded.

[0012] The self-recovery constant current control circuit of the utility model further includes a voltage stabilizer U3, one end of the voltage stabilizer U3 is connected to the relay switch P1, and the other end is connected to the emitter of the switch tube Q5.

[0013] In the self-recovery constant current control circuit of the utility model, the gate of the field effect tube Q2 and the collector of the switch tube Q5 are connected with a diode D5.

[0014] In the self-recovery constant current control circuit of the utility model, the dual operational amplifier U1 adopts the LM358ST chip.

[0015] In the self-recovery constant current control circuit of the utility model, the output voltage of the power module is 12V.

[0016] Through the above technical scheme, the beneficial effects of the utility model are as follows: the utility model sets a self-recovery protection module, and when overcurrent occurs, the comparison circuit unit will feedback information to the switch control unit, thereby controlling the shutdown of the power supply; when the current returns to normal, the comparison circuit unit will enable the switch control unit to drive the power supply to recover, thereby achieving the effect of self-recovery during overcurrent faults.

[0017] This product solution does not require manual power off and restart, which not only improves the reliability of the system, but also avoids the user's misjudgment of power failure, reduces maintenance frequency, thereby reducing maintenance costs, and prolongs the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the circuit structure of an embodiment of the utility model;

[0019] Figure 2 It is a principle block diagram of an embodiment of the utility model.

[0020] 100, current detection module; 200, comparison circuit unit; 300, switch control unit; 400, filter circuit unit. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the utility model more clear, the following is a further detailed description of a self-recovery constant current control circuit of the utility model in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0022] In the description of the present invention, it should be noted that the terms "two ends", "one end", "the other end", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] Please refer to Figure 1-2 A self-recovery constant current control circuit includes: a power module, a current detection module 100 and a self-recovery protection module, the power module is connected to the self-recovery protection module for power supply; the self-recovery protection module includes a comparison circuit unit 200 and a switch control unit 300, one end of the comparison circuit unit 200 is connected to the current detection module 100 to ensure the output of a constant current, and the other end of the comparison circuit unit 200 is connected to the switch control unit 300 to control the power supply to be turned off and turned on. This technical solution sets a self-recovery protection module. When an overcurrent occurs, the comparison circuit unit 200 will feedback information to the switch control unit 300, thereby controlling the power supply to be turned off; when the current returns to normal, the comparison circuit unit 200 will enable the switch control unit 300 to drive the power supply to recover, thereby achieving the effect of self-recovery in the event of an overcurrent fault.

[0024] In this embodiment, the comparison circuit unit 200 includes a dual operational amplifier U1 and a field effect transistor Q1; the gate of the field effect transistor Q1 is connected to the dual operational amplifier U1, the drain of the field effect transistor Q1 is connected to the current detection module, and the source of the field effect transistor Q1 is grounded. Specifically, the current detection module 100 is placed on the load path to detect the current passing through the load, and the voltage drop of the current detection module 100 is proportional to the current passing through the load. The dual operational amplifier U1 compares the voltage signal on the current detection module 100 with the reference voltage Vref, and outputs a control signal to the gate of the field effect transistor Q1. By adjusting the gate voltage of the field effect transistor Q1, the dual operational amplifier U1 can control the current flowing through the load to maintain a constant current output.

[0025] In this embodiment, the switch control unit 300 includes a driving chip U2, a switch tube Q4, a switch tube Q5 and a relay switch P1. The driving chip U2 is connected to the dual operational amplifier U1 to receive feedback information; the driving chip U2 is also connected to the switch tube Q5 to control its on and off states. The switch tube Q5 is connected to the switch tube Q4 through the relay switch P1.

[0026] When the load current exceeds the set value, the output of the dual operational amplifier U1 changes, thereby outputting a signal to the driver chip U2. The driver chip U2 determines whether an overcurrent occurs based on the signal. When the driver chip U2 detects an overcurrent, it outputs a signal to the switch tube Q5, causing the collector current of the switch tube Q5 to flow to the ground, reducing the gate voltage of the switch tube Q4 to turn it off, thereby cutting off the power path and protecting the circuit. When the overcurrent condition is relieved, the voltage on the current detection module 100 returns to normal, the output signal of the dual operational amplifier U1 returns to normal, the driver chip U2 stops outputting the drive signal, the switch tube Q5 is turned off, and the gate voltage of the switch tube Q4 returns to a high level, turns on again, and restores the power path.

[0027] Furthermore, the switch control unit 300 also includes a field effect transistor Q2 and a field effect transistor Q3; the gate of the field effect transistor Q2 is connected to the collector of the switch tube Q5, the source of the switch tube Q2 is connected to the source of the field effect transistor Q3, and the gate of the field effect transistor Q3 is connected to the source. Understandably, under normal current conditions, the output signal of the dual operational amplifier U1 remains stable, the driver chip U2 will not be triggered, the field effect transistor Q2 is turned off, the gate voltage of the field effect transistor Q3 remains high, the field effect transistor Q3 is turned on, and the power path is normal. When an overcurrent condition occurs, the dual operational amplifier U1 will feedback a signal to the driver chip U2, and the driver core U2 will output a high level to the base of the field effect transistor Q2, turning on the field effect transistor Q2, and its collector current flows to the ground, thereby pulling down the gate voltage of the field effect transistor Q3. When the gate voltage of the field effect transistor Q3 is reduced to below the threshold voltage, the field effect transistor Q3 will be turned off, cutting off the power path. The FET Q3 can respond quickly under the drive of the FET Q2, ensuring that the power path is completely cut off in the case of overcurrent, avoiding damage to the circuit and load. The joint control of the switch tube Q4 and the FET Q3 provides double protection to prevent the failure of protection caused by the failure of a single component. After the overcurrent condition is relieved, the output signal of the dual operational amplifier U1 returns to normal, and the driver chip U2 stops outputting high-level signals. The FET Q2 is turned off, the gate voltage of the FET Q3 returns to a high level, and the FET Q3 is turned on again, thereby restoring the power path.

[0028] In this embodiment, the current detection module 100 includes a detection resistor R3. When current passes through the detection resistor R3, a voltage drop proportional to the current is generated at both ends of the detection resistor R3. The voltage drop is used to detect the current size.

[0029] In this embodiment, a filter circuit unit 400 is also included; the filter circuit unit 400 includes a resistor R7 and a capacitor R4 connected in parallel, one end of the filter circuit unit 400 is connected to the gate of the field effect transistor Q1, and the other end is connected to the source of the field effect transistor Q1 and grounded. It can be understood that the filter circuit unit 400 can remove noise, thereby generating a more stable and smoother output current.

[0030] Furthermore, a voltage stabilizer U3 is included, one end of which is connected to the relay switch P1, and the other end is connected to the emitter of the switch tube Q5. In this embodiment, the output voltage of the power module is 12V, which is converted to 9V (DC9V) by the voltage stabilizer U3, and the power supply is decoupled through the filter capacitors C1 and C2 to provide clean power to other circuits.

[0031] In this embodiment, a diode D5 is connected between the gate of the field effect tube Q2 and the collector of the switch tube Q5 to protect the circuit from overvoltage and reverse current and prevent the switch tube Q5 from breaking down.

[0032] In this embodiment, the dual operational amplifier U1 adopts the LM358ST chip. In addition, preferably, the driver chip U2 adopts the FAN3111E model chip.

[0033] In this embodiment, the field effect transistors Q1, Q2 and Q3 are all P-type field effect transistors, and the switch tubes Q4 and Q5 are all P-type triodes.

[0034] In summary, the utility model provides a self-recovering constant current control circuit, and the dual operational amplifier U1 adjusts the gate voltage of the field effect tube Q1 to maintain a constant current output. When the load current exceeds the set value, the output of the dual operational amplifier U1 changes and outputs a signal to the driver chip U2. The driver chip U2 determines whether an overcurrent occurs based on the signal. When the driver chip U2 detects an overcurrent, it outputs a signal to the switch tube Q5, causing the collector current of the switch tube Q5 to flow to the ground, reducing the gate voltage of the switch tube Q4 to turn it off, thereby cutting off the power path and protecting the circuit.

[0035] When the overcurrent condition is removed, the voltage on the current detection module 100 returns to normal, the output signal of the dual operational amplifier U1 returns to normal, the driver chip U2 stops outputting the drive signal, the switch tube Q5 is turned off, and the gate voltage of the switch tube Q4 returns to a high level and is turned on again to restore the power path. This solution does not require manual power off and restart, and can also extend the service life of the equipment.

[0036] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

[0037] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A self-recovering constant current control circuit, characterized in that: include: A power supply module, a current detection module (100) and a self-recovery protection module, wherein the power supply module is connected to the self-recovery protection module for power supply; The self-recovery protection module comprises a comparison circuit unit (200) and a switch control unit (300); one end of the comparison circuit unit (200) is connected to the current detection module (100) to ensure the output of a constant current; the other end of the comparison circuit unit (200) is connected to the switch control unit (300) to control the shutdown and startup recovery of the power supply.

2. A self-recovering constant current control circuit according to claim 1, characterized in that: The comparison circuit unit (200) comprises a dual operational amplifier U1 and a field effect transistor Q1; The gate of the field effect tube Q1 is connected to the dual operational amplifier U1, the drain of the field effect tube Q1 is connected to the current detection module (100), and the source of the field effect tube Q1 is grounded.

3. A self-recovering constant current control circuit according to claim 2, characterized in that: The switch control unit (300) comprises a driving chip U2, a switch tube Q4, a switch tube Q5 and a relay switch P1, wherein the driving chip U2 is connected to the dual operational amplifier U1 to receive feedback information; The driving chip U2 is also connected to the switch tube Q5 to control its on and off states. The switch tube Q5 is connected to the switch tube Q4 through the relay switch P1.

4. A self-recovering constant current control circuit according to claim 3, characterized in that: The switch control unit (300) further includes a field effect transistor Q2 and a field effect transistor Q3; The gate of the field effect tube Q2 is connected to the collector of the switch tube Q5, the source of the switch tube Q2 is connected to the source of the field effect tube Q3, and the gate of the field effect tube Q3 is connected to the source.

5. A self-recovering constant current control circuit according to claim 1, characterized in that: The current detection module (100) comprises a detection resistor R3.

6. A self-recovering constant current control circuit according to claim 2, characterized in that: Also includes a filter circuit unit (400); The filter circuit unit (400) comprises a resistor R7 and a capacitor R4 connected in parallel; one end of the filter circuit unit (400) is connected to the gate of the field effect transistor Q1, and the other end is connected to the source of the field effect transistor Q1 and is grounded.

7. A self-recovering constant current control circuit according to claim 3, characterized in that: It also includes a voltage stabilizer U3, one end of which is connected to the relay switch P1, and the other end of which is connected to the emitter of the switch tube Q5.

8. A self-recovering constant current control circuit according to claim 4, characterized in that: The gate of the field effect tube Q2 and the collector of the switch tube Q5 are connected via a diode D5 .

9. A self-recovering constant current control circuit according to claim 2, characterized in that: The dual operational amplifier U1 adopts LM358ST chip.

10. The self-recovering constant current control circuit according to claim 1, characterized in that: The output voltage of the power module is 12V.

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