CN217904001U - Output overcurrent protection circuit and device - Google Patents
Output overcurrent protection circuit and device Download PDFInfo
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- CN217904001U CN217904001U CN202221817907.3U CN202221817907U CN217904001U CN 217904001 U CN217904001 U CN 217904001U CN 202221817907 U CN202221817907 U CN 202221817907U CN 217904001 U CN217904001 U CN 217904001U
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Abstract
The utility model provides an output overcurrent protection circuit and a device, the output overcurrent protection circuit detects the current signal input to the load through an overcurrent detection circuit and outputs an overcurrent signal to the protection control circuit when the current value of the current signal is greater than the preset current value; the protection control circuit outputs a cut-off signal to the protection execution circuit when receiving the overcurrent signal; the protection execution circuit disconnects the connection between the power supply device and the load upon receiving the cutoff signal. The utility model discloses a detect input load current signal to can break off being connected between power supply unit and the load when current signal is greater than preset current value, thereby provide stable overcurrent protection.
Description
Technical Field
The utility model relates to an overcurrent protection technical field especially relates to an output overcurrent protection circuit and device.
Background
In industrial products, output ports of products such as electric cabinet equipment and the like can provide 24V or even 48V power supply for the outside. When the equipment is used, the problems of equipment burnout or abnormality and the like can occur due to the condition that the output is short-circuited or the output is over-current caused by the non-standard wiring.
In the prior art, a low-dropout linear regulator can be used for stabilizing voltage and then outputting the voltage, and the low-dropout linear regulator has overcurrent limiting and overheating protection functions, but in the scheme, because the input and output voltage differences of an integrated chip of the low-dropout linear regulator are large, the power consumption is large, the allowable through-current capacity is limited, stable overcurrent protection cannot be provided under the condition of large output current, and meanwhile, the input voltage range of the low-dropout linear regulator is small, the application scene of outputting large voltage cannot be met, and the application range of the scheme is limited; in addition, the output current can also pass through the sampling resistor to generate voltage drop so as to trigger the overcurrent signal by determining whether the current is overcurrent or not, but the power consumption of the scheme at two ends of the sampling resistor is U 2 and/R, when the output current is larger, the selected sampling resistance value is very small, so that the transient power consumption generated during output short circuit is very large, the failure of the sampling resistance is easily caused, and the stable overcurrent protection cannot be provided.
The above is only for the purpose of assisting understanding of the technical solutions of the present invention, and does not represent an admission that the above is the prior art.
SUMMERY OF THE UTILITY MODEL
A primary object of the present invention is to provide an output overcurrent protection circuit, which is a device that cannot provide stable overcurrent protection when output current is large in the prior art.
In order to achieve the above object, the utility model provides an output overcurrent protection circuit, a serial communication port, output overcurrent protection circuit includes: the overcurrent protection circuit comprises an overcurrent detection circuit, a protection control circuit and a protection execution circuit;
the protection execution circuit is respectively connected with the overcurrent detection circuit, the protection control circuit and the power supply equipment, and the overcurrent detection circuit is respectively connected with the protection control circuit and the load;
the overcurrent detection circuit is used for detecting a current signal input to the load and outputting an overcurrent signal to the protection control circuit when the current value of the current signal is greater than a preset current value;
the protection control circuit is used for outputting a cut-off signal to the protection execution circuit when receiving the overcurrent signal;
the protection execution circuit is used for disconnecting the power supply equipment from the load when receiving the cut-off signal.
Optionally, the over-current detection circuit includes: the self-recovery fuse, the first resistor and the first switch tube;
the first end of the self-recovery fuse is connected with the output end of the protection execution circuit and the input end of the first switch tube respectively, the second end of the self-recovery fuse is connected with the first end of the first resistor and the load respectively, the second end of the first resistor is connected with the control end of the first switch tube, and the output end of the first switch tube is connected with the protection control circuit.
Optionally, the protection control circuit includes: a second switching tube;
the control end of the second switch tube is connected with the output end of the first switch tube, the input end of the second switch tube is connected with the protection execution circuit, and the output end of the second switch tube is grounded.
Optionally, the protection control circuit further includes: a first voltage division circuit and a first voltage stabilization delay circuit;
the first voltage division circuit is respectively connected with the output end of the first switch tube and the first voltage stabilization delay circuit, and the first voltage stabilization delay circuit is connected with the control end of the second switch tube;
the first voltage division circuit is further configured to divide the voltage of the over-current signal and output the divided over-current signal to the first voltage stabilization delay circuit;
the first voltage stabilization delay circuit is used for stabilizing the voltage of the over-current signal after voltage division to obtain a stable over-current signal, and outputting the stable over-current signal to the control end of the second switch tube to control the conduction of the second switch tube.
Optionally, the first voltage dividing circuit includes: a second resistor and a third resistor;
the first voltage stabilization delay circuit includes: a first capacitor and the second resistor;
the first end of the second resistor is connected with the output end of the first switch tube, the second end of the second resistor is respectively connected with the first end of the third resistor, the control end of the second switch tube and the first end of the first capacitor, and the second end of the third resistor and the second end of the first capacitor are grounded.
Optionally, the protection performing circuit includes: a third switching tube and a fourth switching tube;
wherein, the control end of third switch tube with power supply unit and the input of second switch tube is connected, the input of third switch tube with the control end of fourth switch tube and power supply unit connects, the input of fourth switch tube with power supply unit connects, the output of fourth switch tube respectively with the first end of self-resuming fuse and the input of first switch tube is connected.
Optionally, the protection performing circuit further includes: a second voltage dividing circuit and a third voltage dividing circuit;
one end of the second voltage division circuit is connected with the power supply equipment, and the other end of the second voltage division circuit is connected with the control end of the third switching tube; one end of the third voltage division circuit is connected with the power supply equipment, and the other end of the third voltage division circuit is connected with the control end of the fourth switching tube;
the second voltage division circuit is used for dividing the power supply voltage output by the power supply equipment and outputting the divided first preset voltage to the control end of the third switching tube;
and the third voltage division circuit is used for dividing the power supply voltage output by the power supply equipment and outputting the divided second preset voltage to the control end of the fourth switching tube.
Optionally, the protection performing circuit further includes: a second voltage stabilization delay circuit;
one end of the second voltage-stabilizing delay circuit is connected with the second voltage-dividing circuit, and the other end of the second voltage-stabilizing delay circuit is connected with the control end of the third switching tube;
the second voltage division circuit is further configured to output the first preset voltage to the second voltage stabilization delay circuit;
and the second voltage-stabilizing delay circuit is used for stabilizing the first preset voltage and outputting the stabilized first preset voltage to the control end of the third switching tube.
Optionally, the second voltage dividing circuit includes: a fourth resistor and a fifth resistor;
the third voltage dividing circuit includes: a sixth resistor and a seventh resistor;
the second voltage stabilization delay circuit includes: a second capacitor and the fourth resistor;
wherein, the first end of fourth resistance respectively with power supply unit's output and the first end of sixth resistance is connected, the second end of fourth resistance respectively with the input of second switch tube the first end of fifth resistance the first end of second electric capacity and the control end of third switch tube is connected, the second end of sixth resistance respectively with the control end of fourth switch tube and the first end of seventh resistance are connected, the second end of seventh resistance with the input of third switch tube is connected, the second end of fifth resistance reaches the second end ground connection of second electric capacity.
In order to achieve the above object, the utility model also provides an output overcurrent protection device, output overcurrent protection device includes foretell output overcurrent protection circuit.
The utility model provides an output overcurrent protection circuit and a device, wherein the output overcurrent protection circuit comprises an overcurrent detection circuit, a protection control circuit and a protection execution circuit; the protection execution circuit is respectively connected with the overcurrent detection circuit, the protection control circuit and the power supply equipment, and the overcurrent detection circuit is respectively connected with the protection control circuit and the load; the overcurrent detection circuit detects a current signal input to the load and outputs an overcurrent signal to the protection control circuit when the current value of the current signal is greater than a preset current value; the protection control circuit outputs a cut-off signal to the protection execution circuit when receiving the overcurrent signal; the protection execution circuit disconnects the connection between the power supply device and the load upon receiving the cutoff signal. The utility model discloses a detect input load current signal to can break off being connected between power supply unit and the load when current signal is greater than preset current value, thereby provide stable overcurrent protection.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a schematic circuit structure diagram of a first embodiment of the output overcurrent protection circuit of the present invention;
fig. 2 is a schematic circuit structure diagram of a second embodiment of the output overcurrent protection circuit of the present invention;
fig. 3 is a schematic circuit diagram of a second embodiment provided by the output overcurrent protection circuit of the present invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) |
| 10 | Overcurrent detection circuit | Q1～Q4 | First to fourth |
| 20 | Protection control circuit | C1～C2 | First to |
| 30 | Protection execution circuit | R1～R7 | First to seventh resistors |
| 201 | A first voltage dividing circuit | F | Self- |
| 202 | First voltage-stabilizing |
302 | Third voltage dividing |
| 301 | Second |
303 | Second voltage-stabilizing delay circuit |
The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front, and rear … …) in the embodiments of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory to each other or cannot be realized, the combination of the technical solutions should be considered to be absent, and is not within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic circuit structure diagram of a first embodiment provided by the output overcurrent protection circuit of the present invention. Put forward based on fig. 1 the utility model discloses output overcurrent protection circuit's first embodiment.
As shown in fig. 1, in this embodiment, the output overcurrent protection circuit includes: an overcurrent detection circuit 10, a protection control circuit 20, and a protection execution circuit 30;
the protection execution circuit 30 is connected to the over-current detection circuit 10, the protection control circuit 20, and the power supply device, and the over-current detection circuit 10 is connected to the protection control circuit 20 and the load.
It will be appreciated that the value of the current output will be large due to the short circuit condition, but the short circuit is not the same as the over current condition. In the scheme, the output overcurrent protection comprises two states of overlarge output current value and short circuit, and the output overcurrent protection state comprises a protection state and a short circuit protection state of overlarge output current value. Although there is a related structure for overcurrent protection in the prior art, for example, a structure related to a low dropout regulator or a sampling resistor, the current capacity of the low dropout regulator is limited and the sampling resistor is prone to failure under the condition of a large rated current; the above structure can not provide stable overcurrent protection under the condition of larger output rated current.
The overcurrent detection circuit 10 is a circuit for detecting whether or not the current output from the power supply device is an overcurrent. When the current of the input load is determined to be in the overcurrent state, the current value of the input load can be compared with a preset current value through a comparator, and when the current value of the input load is larger than the preset current value, the current input to the load can be determined to be in the overcurrent state; of course, when the current value changes, the heat generated by the current passing through the resistor, the transistor, or other components also changes, so that the heat generated by the current can be used to determine whether the current input to the load is in an overcurrent state. The protection execution circuit 30 is a circuit that performs protection against overcurrent. The protection execution circuit 30 may control connection between the power supply device and the load. When the current input to the load is in an overcurrent state, the protection execution circuit 30 may disconnect the power supply loop between the power supply device and the load, so as to avoid the influence of the overcurrent on the load. The protection control circuit 20 is a circuit for controlling the protection execution circuit 30. When the current input to the load is in the overcurrent state, the protection control circuit 20 may control the protection performing circuit 30 to perform overcurrent protection.
In a specific implementation, the over-current detection circuit 10 may detect a current signal input to the load, and output an over-current signal to the protection control circuit 20 when a current value of the current signal is greater than a preset current value; the protection control circuit 20 may output a cutoff signal to the protection execution circuit upon receiving the overcurrent signal; the protection execution circuit 30 may disconnect the connection between the power supply device and the load upon receiving the cutoff signal.
The preset current value is a preset current value used for determining whether the current input to the load is in an overcurrent state. The preset current value may be a maximum current value that the load can receive, and the load may be affected when the current value of the input current signal is greater than the preset current value. In the current comparison process, the comparison may be performed by inputting the current value of the current signal and the preset current value to the comparator in a voltage manner through the same resistor. The cutoff signal is a signal for controlling the protection execution circuit 30 to disconnect the connection between the power supply device and the load.
The embodiment provides an output overcurrent protection circuit, which comprises an overcurrent detection circuit, a protection control circuit and a protection execution circuit; the protection execution circuit is respectively connected with the overcurrent detection circuit, the protection control circuit and the power supply equipment, and the overcurrent detection circuit is respectively connected with the protection control circuit and the load; the overcurrent detection circuit detects a current signal input to the load and outputs an overcurrent signal to the protection control circuit when the current value of the current signal is greater than a preset current value; the protection control circuit outputs a cut-off signal to the protection execution circuit when receiving the overcurrent signal; the protection execution circuit disconnects the connection between the power supply device and the load upon receiving the cutoff signal. The embodiment detects the input load current signal, and can disconnect the connection between the power supply equipment and the load when the current signal is greater than the preset current value, so that stable overcurrent protection is provided.
Referring to fig. 2, fig. 2 is a schematic circuit structure diagram of a second embodiment provided by the output overcurrent protection circuit of the present invention. Based on above-mentioned output overcurrent protection circuit's first embodiment, provide the utility model discloses output overcurrent protection circuit's second embodiment.
In this embodiment, the over-current detection circuit includes: the self-recovery fuse F, the first resistor R1 and the first switch tube Q1;
the first end of the self-recovery fuse F is connected to the output end of the protection execution circuit 30 and the input end of the first switch tube Q1, the second end of the self-recovery fuse F is connected to the first end of the first resistor R1 and the load, the second end of the first resistor R1 is connected to the control end of the first switch tube Q1, and the output end of the first switch tube Q1 is connected to the protection control circuit 20.
It should be noted that the self-recovery fuse F is a fuse that can be automatically recovered after an overcurrent has passed. The self-recovery fuse F is made of a semi-crystalline polymer and a polymer of conductive ions, when the temperature rises above the action temperature of the device due to high current of the device, crystalline grains in the polymer melt and form an amorphous state, and meanwhile, the conductive ions are increased to be separated, so that the resistance of the device is greatly increased in a nonlinear mode, the self-recovery fuse F works in a high-resistance state after overcurrent, whether the current of an input load is in the overcurrent state or not can be determined according to the resistance value of the self-recovery fuse F, for example, the resistance value of the self-recovery fuse F is changed under the condition that the overcurrent passes through the self-recovery fuse F, the voltage value of two ends of the self-recovery fuse F is increased, and whether the current of the input load is in the overcurrent state or not can be determined by judging the voltage value of two ends of the self-recovery fuse F. The first switch tube Q1 is a power tube with certain control logic, such as a triode, a MOS tube, etc. Referring to fig. 3, the first switching transistor Q1 is illustrated as a transistor in fig. 3, which is a PNP transistor.
Referring to fig. 3, in a specific implementation, in the presence of an overcurrent, the current value of the self-recovery fuse F is greater than the current value required by the load, and at this time, the resistance value of the self-recovery fuse F changes nonlinearly with the current value in the overcurrent state, and the voltage value at the two ends of the self-recovery fuse F increases accordingly. When the voltage value across the self-healing fuse F increases, the voltage difference between the voltage of the emitter of the first switching tube Q1 and the voltage inputted to the base of the first switching tube Q through the first resistor R1 increases. When the current input to the load is in an overcurrent state, the voltage difference between the emitter and the base of the first switching tube Q1 is directly caused to be greater than the conduction threshold voltage of the first switching tube Q1, the first switching tube Q1 is conducted, and a corresponding overcurrent signal can be output to the protection control circuit 20 through the conducted first switching tube Q1.
In the present embodiment, the protection control circuit 20 includes: a second switching tube Q2;
the control end of the second switch tube Q2 is connected to the output end of the first switch tube Q1, the input end of the second switch tube Q2 is connected to the protection execution circuit 30, and the output end of the second switch tube Q2 is grounded GND.
It should be noted that, the input end of the second switch tube Q2 is connected to the protection execution circuit 30, and the second switch tube Q2 can directly introduce the port connected to the second switch tube Q2 or the control end of the device in the protection execution circuit 30 to the ground in the on state; in the state that the second switch tube Q2 is turned off, the corresponding port or the control terminal of the device is not grounded. The second switching transistor Q2 may be an NPN type MOS transistor.
In this embodiment, referring to fig. 3, the protection control circuit 20 may provide different control signals to the protection execution circuit 30 by turning on or off the second switch Q2.
In this embodiment, the protection control circuit 20 further includes: a first voltage division circuit 201 and a first voltage stabilization delay circuit 202;
the first voltage dividing circuit 201 is connected to the output end of the first switch Q1 and the first voltage-stabilizing delay circuit 202, and the first voltage-stabilizing delay circuit 202 is connected to the control end of the second switch Q2.
It should be understood that the voltage value inputted to the gate of the second switching tube Q2 through the first switching tube Q1 varies with the current value. In an overcurrent state, in order to avoid an excessive voltage value directly input to the gate of the second switching tube Q2, a voltage dividing circuit may be provided to divide the voltage input to the gate of the second switching tube Q2. In addition, because energy storage elements such as a capacitor and an inductor may exist in the load, the voltage input to the gate of the second switching tube Q2 may also have a certain fluctuation, and in order to avoid the influence of the voltage fluctuation on the conduction state of the second switching tube Q2 to form an error protection, a voltage stabilization delay circuit may be further provided to stabilize the voltage input to the gate of the second switching tube Q2. The first voltage dividing circuit 201 is a circuit for dividing the voltage input to the gate of the second switching tube Q2. The first voltage stabilization delay circuit 202 is a circuit for stabilizing a voltage input to the gate of the second switching transistor Q2. Referring to fig. 3, in the present embodiment, when the protection execution circuit 30 controls the disconnection between the power supply device and the load, the state of the first switching tube Q1 is directly switched to the off state, and the second switching tube Q2 is also turned off, so that the protection execution circuit 30 stops executing the protection. At this time, there is a long time of overcurrent passing through the self-recovery fuse F, which causes the self-recovery fuse F to be in an overheat state. Therefore, the first voltage regulation delay circuit 202 in this embodiment can also provide a stable on-voltage for a period of time to form hiccup protection for the second switching tube Q2 when the first switching tube Q1 is turned off, so as to avoid the protection execution circuit 30 directly stopping protection, which results in an excessively high temperature of the self-healing fuse F.
In a specific implementation, the first voltage dividing circuit 201 may divide a voltage value corresponding to the over-current signal when receiving the over-current signal output by the output end of the first switching tube Q1, to obtain the over-current signal that does not affect the second switching tube Q2, and then output the divided over-current signal to the voltage stabilization delay circuit 202; the voltage stabilization delay circuit 202 may stabilize the divided overcurrent signal when receiving the divided overcurrent signal, obtain a stable overcurrent signal after a period of voltage stabilization, output the stable overcurrent signal to the control end of the second switch tube Q2, and control the second switch tube Q2 to be turned on, thereby outputting the cut-off instruction to the protection execution circuit 30.
In this embodiment, the first voltage dividing circuit 201 includes: a second resistor R2 and a third resistor R3;
the first voltage regulation delay circuit 202 includes: a first capacitor C1 and the second resistor R2;
a first end of the second resistor R2 is connected to an output end of the first switch Q1, a second end of the second resistor R2 is connected to a first end of the third resistor R3, a control end of the second switch Q2, and a first end of the first capacitor C1, respectively, and a second end of the third resistor R3 and a second end of the first capacitor C1 are grounded GND.
It should be understood that the first voltage dividing circuit 201 and the first voltage stabilizing delay circuit 202 may share the same second resistor R2, and the second resistor R2 and the third resistor R3 with appropriate resistance values may be selected; of course, two resistors may be provided here. For example, the second resistor R2 is only used to form a voltage dividing circuit with the third resistor R3 for voltage division, and then another resistor is arranged to form a voltage stabilizing delay circuit with the first capacitor C1 for voltage stabilization. Due to the charge-discharge characteristics of the capacitor, the first voltage-stabilizing delay circuit 201 can be formed by the first capacitor C1 and the second resistor R2, so that the overcurrent signal input to the gate of the second switching tube Q2 is stabilized.
Referring to fig. 3, in a specific implementation, when the first switching tube Q1 outputs an overcurrent signal, the overcurrent signal may be divided by the second resistor R2 and the third resistor R3, and then the first capacitor C1 is charged through the second end of the second resistor R2, after the first capacitor C1 is charged, a stable overcurrent signal may be obtained, and the stable overcurrent signal is input to the gate of the second switching tube Q2 to control the second switching tube Q2 to be turned on. When the second switch Q2 is turned on, the state of the switch in the protection execution circuit 30 may be changed, so as to disconnect the power supply device from the load.
In the present embodiment, the protection execution circuit 30 includes: a third switching tube Q3 and a fourth switching tube Q4;
wherein, the control end of third switch tube Q3 with power supply unit and the input of second switch tube Q2 is connected, the input of third switch tube Q3 with the control end of fourth switch tube Q4 and power supply unit connects, the input of fourth switch tube Q4 with power supply unit connects, the output of fourth switch tube Q4 respectively with the first end of self-resuming fuse and the input of first switch tube Q1 is connected.
Referring to fig. 3, it should be understood that the third switching transistor Q3 and the fourth switching transistor Q4 may be MOS transistors, wherein the third switching transistor Q3 is an NPN type MOS transistor, and the fourth switching transistor Q4 is a PNP type MOS transistor.
During the protection execution, since the grid electrode of the third switching tube Q3 is respectively connected with the power supply equipment and the input end of the second switching tube Q2, under the condition that the second switching tube Q2 is conducted, the control end of the third switching tube Q3 is approximately short-circuited to the ground, and the voltage of the control end of the third switching tube Q3 is about 0V. And in the state that the second switching tube Q2 is turned off, the power supply device may supply power to the gate of the third switching tube Q3, so as to control the third switching tube Q3 to be turned on. When the third switching tube Q3 is turned off, the control terminal and the input terminal of the fourth switching tube Q4 have the same level, and the fourth switching tube Q4 is also in the off state, so that the connection between the power supply device and the load is disconnected.
In this embodiment, the protection execution circuit 30 further includes: a second voltage dividing circuit 301 and a third voltage dividing circuit 302;
one end of the second voltage division circuit 301 is connected to the power supply device, and the other end is connected to the control end of the third switching tube Q3; one end of the third voltage dividing circuit 302 is connected to the power supply device, and the other end is connected to the control end of the fourth switching tube Q4.
It should be understood that the gates of the third switching tube Q3 and the fourth switching tube Q4 are both connected to the output terminal of the power supply device, and in the case that the output voltage value of the power supply device is large, the operating state of the third switching tube Q3 and the fourth switching tube Q4 may be affected, or even broken down. Therefore, a second voltage dividing circuit 301 may be provided between the gate of the third switching tube Q3 and the power supply device to divide the voltage directly input to the third switching tube Q3 by the power supply device. Similarly, the third voltage dividing circuit 302 may divide the voltage input by the power supply device to the gate of the fourth switching tube Q4.
In this embodiment, the protection execution circuit 30 further includes: a second voltage stabilization delay circuit 303;
one end of the second voltage regulation delay circuit 303 is connected to the second voltage division circuit 301, and the other end is connected to the control end of the third switching tube Q3.
It should be understood that, during the conducting process of the third switching tube Q3, there may be a certain fluctuation in the power supply voltage output by the power supply device due to factors such as electromagnetic interference, and at this time, a voltage stabilizing delay circuit may be further disposed between the second voltage stabilizing circuit 301 and the gate of the third switching tube Q3 to stabilize the divided power supply voltage. In addition, under the condition that the fourth switch tube Q4 is disconnected, the current input to the load is zero, the first switch tube Q1 is cut off, the second switch tube Q2 is cut off after the first voltage-stabilizing delay circuit 202 delays for a period of time, the third switch tube Q3 and the fourth switch tube Q4 are further caused to be directly conducted, the current with a high current value can be directly input to the load again through the fourth switch tube Q4, at the moment, the second voltage-stabilizing delay circuit 303 can be further arranged, the cut-off state of the third switch tube Q3 can be maintained for a certain period of time through the second voltage-stabilizing delay circuit 303, and hiccup delay protection is also formed.
In a specific implementation, the second voltage division circuit 301 may divide a power voltage output by the power supply device, and output a first preset voltage after the voltage division to the control end of the third switching tube Q3; the third voltage dividing circuit 302 may divide the power voltage output by the power supply device, and output a second preset voltage after the voltage division to the control end of the fourth switching tube Q4. In addition, the second voltage dividing circuit 301 may further output the first preset voltage to the second voltage regulation delay circuit 303; the second voltage-stabilizing delay circuit 303 may stabilize the first preset voltage, and continuously output the stabilized first preset voltage to the control end of the third switching transistor Q3 within a delay time.
The first preset voltage is a voltage required by the gate of the third switching transistor Q3. The second preset voltage is the voltage required by the grid electrode of the fourth switching tube Q4.
In this embodiment, the second voltage dividing circuit 301 includes: a fourth resistor R4 and a fifth resistor R5;
the third voltage dividing circuit 302 includes: a sixth resistor R6 and a seventh resistor R7;
the second voltage stabilization delay circuit 303 includes: a second capacitor C2 and the fourth resistor R4;
the first end of the fourth resistor R4 is connected to the output end of the power supply device and the first end of the sixth resistor R6, the second end of the fourth resistor R4 is connected to the input end of the second switch tube Q2, the first end of the fifth resistor R5, the first end of the second capacitor C2 and the control end of the third switch tube Q3, the second end of the sixth resistor R6 is connected to the control end of the fourth switch tube Q4 and the first end of the seventh resistor R7, the second end of the seventh resistor R7 is connected to the input end of the third switch tube Q3, and the second end of the fifth resistor R5 and the second end of the second capacitor C2 are grounded GND.
Referring to fig. 3, in this embodiment, in the state where the second switching tube Q2 is turned on, the voltage provided by the power supply device to the control terminal of the third switching tube Q3 is directly grounded through the fourth resistor R4 and the second switching tube Q2, the third switching tube Q3 is in the off state, and the fourth switching tube Q4 is in the off state, so as to disconnect the power supply device from the load. When the second switching tube Q2 is in the off state, the voltage output by the power supply device may be divided by the fourth resistor R4 and the fifth resistor R5, and then the second end of the fourth resistor R4 and the second capacitor C2 provide a stable voltage for the control end of the third switching tube Q3, so as to control the third switching tube Q3 to be turned on. When the third switching tube Q3 is turned on, the voltage of the power supply device may also be grounded through the sixth resistor R6, the seventh resistor R7 and the third switching tube Q3, so as to form a conducting voltage difference between the gate and the source of the fourth switching tube Q4, thereby controlling the fourth switching tube Q4 to be turned on.
The embodiment detects the input load current signal through the self-recovery fuse F, and the connection between the power supply equipment and the load can be disconnected through the control logic change of the second to fourth switching tubes when the current signal is greater than the preset current value, so that stable overcurrent hiccup protection is provided. The circuit structure in the scheme has the advantages of low cost, good stability and wide usability aiming at overcurrent protection in large current output and large voltage output.
In order to achieve the above object, the present invention further provides an output overcurrent protection device, which includes the output overcurrent protection circuit as described above. The specific structure of the circuit refers to the above embodiments, and since the present device adopts all the technical solutions of all the above embodiments, at least all the beneficial effects brought by the technical solutions of the above embodiments are achieved, and no further description is given here.
The above is only the preferred embodiment of the present invention, and the patent scope of the present invention is not limited thereby, and all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings of the present invention, or directly or indirectly applied to other related technical fields, are included in the same way in the patent protection scope of the present invention.
Claims (10)
1. An output overcurrent protection circuit, comprising: the overcurrent protection circuit comprises an overcurrent detection circuit, a protection control circuit and a protection execution circuit;
the protection execution circuit is respectively connected with the overcurrent detection circuit, the protection control circuit and the power supply equipment, and the overcurrent detection circuit is respectively connected with the protection control circuit and the load;
the overcurrent detection circuit is used for detecting a current signal input to the load and outputting an overcurrent signal to the protection control circuit when the current value of the current signal is greater than a preset current value;
the protection control circuit is used for outputting a cut-off signal to the protection execution circuit when receiving the overcurrent signal;
the protection execution circuit is used for disconnecting the power supply equipment from the load when receiving the cut-off signal.
2. The output overcurrent protection circuit of claim 1, wherein the overcurrent detection circuit comprises: the self-recovery fuse, the first resistor and the first switch tube;
the first end of the self-recovery fuse is connected with the output end of the protection execution circuit and the input end of the first switch tube respectively, the second end of the self-recovery fuse is connected with the first end of the first resistor and the load respectively, the second end of the first resistor is connected with the control end of the first switch tube, and the output end of the first switch tube is connected with the protection control circuit.
3. The output overcurrent protection circuit of claim 2, wherein the protection control circuit comprises: a second switching tube;
the control end of the second switch tube is connected with the output end of the first switch tube, the input end of the second switch tube is connected with the protection execution circuit, and the output end of the second switch tube is grounded.
4. The output overcurrent protection circuit of claim 3, wherein the protection control circuit further comprises: a first voltage division circuit and a first voltage stabilization delay circuit;
the first voltage division circuit is respectively connected with the output end of the first switch tube and the first voltage stabilization delay circuit, and the first voltage stabilization delay circuit is connected with the control end of the second switch tube;
the first voltage division circuit is further configured to divide the voltage of the over-current signal and output the divided over-current signal to the first voltage stabilization delay circuit;
the first voltage stabilization delay circuit is used for stabilizing the voltage of the over-current signal after voltage division to obtain a stable over-current signal, and outputting the stable over-current signal to the control end of the second switch tube to control the conduction of the second switch tube.
5. The output overcurrent protection circuit of claim 4, wherein the first voltage divider circuit comprises: a second resistor and a third resistor;
the first voltage stabilization delay circuit includes: a first capacitor and the second resistor;
the first end of the second resistor is connected with the output end of the first switch tube, the second end of the second resistor is respectively connected with the first end of the third resistor, the control end of the second switch tube and the first end of the first capacitor, and the second end of the third resistor and the second end of the first capacitor are grounded.
6. The output overcurrent protection circuit of claim 5, wherein the protection execution circuit comprises: a third switching tube and a fourth switching tube;
wherein, the control end of third switch tube with power supply unit and the input of second switch tube is connected, the input of third switch tube with the control end of fourth switch tube and power supply unit connects, the input of fourth switch tube with power supply unit connects, the output of fourth switch tube respectively with the first end of self-resuming fuse and the input of first switch tube is connected.
7. The output overcurrent protection circuit of claim 6, wherein the protection execution circuit further comprises: a second voltage dividing circuit and a third voltage dividing circuit;
one end of the second voltage division circuit is connected with the power supply equipment, and the other end of the second voltage division circuit is connected with the control end of the third switching tube; one end of the third voltage division circuit is connected with the power supply equipment, and the other end of the third voltage division circuit is connected with the control end of the fourth switching tube;
the second voltage division circuit is used for dividing the power supply voltage output by the power supply equipment and outputting the divided first preset voltage to the control end of the third switching tube;
and the third voltage division circuit is used for dividing the power supply voltage output by the power supply equipment and outputting the divided second preset voltage to the control end of the fourth switching tube.
8. The output overcurrent protection circuit of claim 7, wherein the protection execution circuit further comprises: a second voltage stabilization delay circuit;
one end of the second voltage-stabilizing delay circuit is connected with the second voltage-dividing circuit, and the other end of the second voltage-stabilizing delay circuit is connected with the control end of the third switching tube;
the second voltage division circuit is further configured to output the first preset voltage to the second voltage stabilization delay circuit;
and the second voltage-stabilizing delay circuit is used for stabilizing the first preset voltage and outputting the stabilized first preset voltage to the control end of the third switching tube.
9. The output overcurrent protection circuit of claim 8, wherein the second voltage divider circuit comprises: a fourth resistor and a fifth resistor;
the third voltage dividing circuit includes: a sixth resistor and a seventh resistor;
the second voltage stabilization delay circuit includes: a second capacitor and the fourth resistor;
wherein, the first end of fourth resistance respectively with power supply unit's output and the first end of sixth resistance is connected, the second end of fourth resistance respectively with the input of second switch tube the first end of fifth resistance the first end of second electric capacity and the control end of third switch tube is connected, the second end of sixth resistance respectively with the control end of fourth switch tube and the first end of seventh resistance are connected, the second end of seventh resistance with the input of third switch tube is connected, the second end of fifth resistance reaches the second end ground connection of second electric capacity.
10. An output overcurrent protection arrangement, characterized in that the output overcurrent protection arrangement comprises an output overcurrent protection circuit according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221817907.3U CN217904001U (en) | 2022-07-14 | 2022-07-14 | Output overcurrent protection circuit and device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221817907.3U CN217904001U (en) | 2022-07-14 | 2022-07-14 | Output overcurrent protection circuit and device |
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| CN217904001U true CN217904001U (en) | 2022-11-25 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116682338A (en) * | 2023-06-16 | 2023-09-01 | 昆山迈致治具科技有限公司 | Voltage control circuit and universal screen test board |
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2022
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116682338A (en) * | 2023-06-16 | 2023-09-01 | 昆山迈致治具科技有限公司 | Voltage control circuit and universal screen test board |
| CN116682338B (en) * | 2023-06-16 | 2023-12-22 | 昆山迈致治具科技有限公司 | Voltage control circuit and universal screen test board |
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