CN211377578U - Overcurrent protection device and system - Google Patents
Overcurrent protection device and system Download PDFInfo
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- CN211377578U CN211377578U CN201922176892.1U CN201922176892U CN211377578U CN 211377578 U CN211377578 U CN 211377578U CN 201922176892 U CN201922176892 U CN 201922176892U CN 211377578 U CN211377578 U CN 211377578U
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Abstract
The utility model provides an overcurrent protection device and system belongs to electron technical field. The utility model provides a pair of overcurrent protection device, including output rectifier circuit, voltage controller and voltage feedback circuit, wherein output rectifier circuit's input receives external voltage, and the output links to each other with the load, and voltage controller links to each other with output rectifier circuit, and voltage feedback circuit links to each other with output rectifier circuit and voltage controller. Because the voltage feedback circuit detects load voltage change and feeds back the load voltage change to the voltage controller, if the load voltage increases suddenly, the voltage controller can adjust output voltage to reduce the output voltage, and the output voltage after adjustment is transmitted to the load after being rectified by the output rectifying circuit, so that the size of current passing through the load can be limited, and the load can be prevented from being damaged due to overlarge current passing through the load.
Description
Technical Field
The utility model belongs to the technical field of the electron, concretely relates to overcurrent protection device and system.
Background
In a conventional overcurrent protection device, a circuit breaking method is usually adopted to protect equipment, that is, a fuse or the like is arranged in a circuit, and if a current passing through the equipment is too large, the fuse is fused to cut off the circuit, so as to achieve the purpose of protecting the equipment.
However, in some special cases, for example, at the moment of turning on the device, an instantaneous surge current is often generated, the current value of the current is large, but the instantaneous surge current does not cause damage to the device itself, and the fuse is blown due to the instantaneous surge current, that is, a blowing misjudgment occurs.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving one of the technical problem that exists among the prior art at least, provide an overcurrent protection device, it can be too big through the electric current of load, when causing load voltage too big, will export the output voltage for the load and turn down to can restrict the size through the electric current of load, and then can avoid the load because the electric current is too big and impaired.
Solve the utility model discloses technical scheme that technical problem adopted is an overcurrent protection device, include:
the input end of the output rectifying circuit receives external voltage, and the output end of the output rectifying circuit is coupled with a load and used for rectifying the external voltage received by the input end and transmitting the rectified external voltage to the load;
the voltage controller is connected with the output rectifying circuit and used for adjusting the output voltage of the output end;
and the voltage feedback circuit is connected with the output rectifying circuit and the voltage controller, is coupled with the load, and is used for detecting the voltage of the load and feeding back the voltage of the load to the voltage controller so that the voltage controller adjusts the output voltage of the output end according to the fed-back voltage of the load.
The utility model provides an above-mentioned overcurrent protection device, because the load voltage change is listened to the voltage feedback circuit, and give voltage controller with load voltage change feedback, if load voltage increases suddenly, voltage controller can adjust output voltage and reduce output voltage, output voltage after adjusting transmits for the load after output rectifier circuit rectification again, consequently, can be in the electric current increase suddenly through the load, when causing load voltage increase suddenly, the output voltage for the load is transferred and is reduced, thereby can restrict the size of the electric current through the load, and then can avoid the load because of the electric current through too big impaired.
Preferably, in the above overcurrent protection device according to the present invention, the voltage feedback circuit includes:
one end of the detection resistor is connected with the output rectifying circuit, the other end of the detection resistor is coupled with the load, and the voltage change degree of the detection resistor is the same as that of the load;
the operational amplifier sub-circuit is connected with the detection resistor and is used for detecting the voltage change of the detection resistor and amplifying the voltage change of the detection resistor;
and the optical coupler sub-circuit is connected between the voltage controller and the operational amplifier sub-circuit, is used for improving the reliability of the detected voltage change and feeds the detected voltage change back to the voltage controller.
Preferably, in the above overcurrent protection device according to the present invention, the operational amplifier circuit includes: the circuit comprises a first triode, a first resistor, a second resistor, a first diode, a first capacitor, a second capacitor, a third resistor, a comparator, a fourth resistor, a second diode, a third capacitor, a fifth resistor and a sixth resistor; wherein,
the collector of the first triode is connected with the optical coupler circuit, and the base of the first triode is sequentially connected with the second resistor, the first diode and the output end of the comparator in series;
the first end of the first resistor is connected with the base electrode of the first triode, and the second end of the first resistor is connected with a first power supply voltage end;
the first capacitor is connected with the third resistor in series and is connected with the second capacitor in parallel to form an operational amplifier feedback sub-circuit, the first end of the operational amplifier feedback sub-circuit is connected with the output end of the comparator, and the second end of the operational amplifier feedback sub-circuit is connected with the negative end of the comparator;
the first end of the fourth resistor is connected to the positive end of the comparator, and the second end of the fourth resistor is connected to the detection resistor, the second diode and the third capacitor;
and the first end of the fifth resistor is connected to the negative end of the comparator, and the second end of the fifth resistor is connected with the sixth resistor.
Preferably, in the above overcurrent protection device provided by the present invention, the optical coupler sub-circuit includes an input terminal and an output terminal;
the input end of the optical coupling sub-circuit comprises a light emitting diode and a seventh resistor which are connected in series, and the light emitting diode is connected with the operational amplifier sub-circuit;
the output end of the optical coupler sub-circuit comprises a phototriode, and the collector electrode of the phototriode is connected with the voltage controller.
Preferably, in the above overcurrent protection device provided by the present invention, the voltage controller includes a pulse width modulator for generating a pulse signal, and the output voltage of the output terminal is controlled by adjusting a width of the pulse signal.
Preferably, in the above overcurrent protection device provided by the present invention, the output rectification circuit includes a transformer, a primary side of the transformer includes a first winding, and a secondary side of the transformer includes a second winding and a third winding; wherein,
the homonymous terminal of the first winding receives external voltage, and the synonym terminal of the first winding is connected to the voltage controller;
the synonym end of the second winding is connected with the voltage controller to provide working voltage for the voltage controller;
and the dotted terminal of the third winding is connected with the voltage feedback circuit.
Preferably, in the above overcurrent protection device provided by the present invention, the output rectification circuit further includes a synchronous rectifier sub-circuit and an eighth resistor, the synchronous rectifier sub-circuit is connected between the second winding and the voltage controller, and is configured to rectify an external voltage and convert the external voltage into a working voltage of the voltage controller;
the synchronous rectifier sub-circuit comprises a fourth capacitor and a third diode, wherein the first end of the third diode is connected with the voltage controller, the second end of the third diode is connected with the synonym end of the second winding, the first end of the fourth capacitor is connected with the first end of the third diode, and the second end of the fourth capacitor is connected with the second power supply voltage end;
the eighth resistor is connected between the dotted terminal of the first winding and the voltage controller.
Preferably, in the above overcurrent protection device provided by the present invention, the output rectification circuit further includes a filter rectifier sub-circuit connected between the load and the third winding.
Preferably, in the above overcurrent protection device provided by the present invention, the filter rectifier sub-circuit includes a pi-type filter rectifier sub-circuit, and the pi-type filter rectifier sub-circuit includes: the fourth diode, the first inductor, the fifth capacitor, the sixth capacitor, the seventh capacitor and the ninth resistor; wherein,
the first end of the fourth diode is connected with the different name end of the third winding;
the first end of the first inductor is connected with the second end of the fourth diode, and the second end of the first inductor is connected with the load;
the first end of the sixth capacitor is connected between the first inductor and the fourth diode, and the second end of the sixth capacitor is connected with the voltage feedback circuit;
the first end of the seventh capacitor is connected with the second end of the first inductor, and the second end of the seventh capacitor is connected with the voltage feedback circuit;
and the fifth capacitor is connected with the ninth resistor in series, and two ends of the circuit after series connection are connected to two ends of the fourth diode.
Correspondingly, the utility model also provides an overcurrent protection system, including the aforesaid arbitrary overcurrent protection device.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of an overcurrent protection apparatus provided by the present invention;
fig. 2 is a schematic circuit diagram of an embodiment of the overcurrent protection apparatus according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, 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.
The shapes and sizes of the various elements in the drawings are not to scale and are merely intended to facilitate an understanding of the contents of the embodiments of the present invention.
As shown in fig. 1, the present embodiment provides an overcurrent protection apparatus, including: the output rectifier circuit 1, the voltage controller 2 and the voltage feedback circuit 3.
Specifically, the output rectifier circuit 1 includes an input terminal and an output terminal, and the input terminal and the output terminal of the output rectifier circuit 1 also serve as the input terminal and the output terminal of the entire overcurrent protection device. The input end of the output rectification circuit 1 receives an external voltage VinAn output end of the output rectifying circuit 1 is coupled to a load, and the output rectifying circuit 1 is used for receiving an external voltage V received by an input end of the output rectifying circuit 1inAfter being rectified, the voltage is converted into output voltage VoutThen the output voltage V is adjustedoutTo a load. The voltage controller 2 is connected with the output rectification circuit 1, and the voltage controller 2 is used for adjusting the output voltage V of the output end of the output rectification circuit 1outHigh and low. The voltage feedback circuit 3 is connected with the output rectification circuit 1 and the voltage controller 2, the voltage feedback circuit 3 is coupled with the load, the voltage feedback circuit 3 is used for detecting the voltage change of the load and feeding the voltage change of the load back to the voltage controller 2, and the voltage controller 2 adjusts the output voltage of the output end of the output rectification circuit 1 according to the fed back voltage change of the load.
In the over-current protection device provided in this embodiment, since the voltage feedback circuit 3 is disposed in the device, the voltage feedback circuit 3 is coupled to the load, and detects the load voltage variation in real time and feeds back the load voltage variation to the voltage controller 2, if the external voltage V is applied, the external voltage V is required to pass through the over-current protection device and then is output to the loadinWhen the load voltage suddenly increases due to an excessive current, the voltage feedback circuit 3 will feed back the detected load voltage change to the voltage controller 2, and the voltage controller 2 will reverse the voltage according to the detected load voltage changeLoad voltage variation fed back by the feed circuit 3 to the output voltage VoutAmplitude modulation, i.e. modulating the output voltage VoutReduced, reduced output voltage VoutThen the output voltage is rectified by the output rectifying circuit 1 and transmitted to the load, so that the output voltage can be quickly and accurately adjusted, the current passing through the load is limited, and the load is prevented from being damaged due to overlarge passing current.
Alternatively, in the above overcurrent protection device provided in this embodiment, the voltage controller 2 may be various types of devices, for example, the voltage controller 2 may include a Pulse Width Modulation (PWM) device having a microprocessor therein and a Metal Oxide Semiconductor field effect (MOS) transistor or a transistor, the Pulse modulator is configured to generate a Pulse signal, and the output voltage V at the output end of the output rectification circuit 1 is controlled by adjusting the width of the Pulse signalout. Specifically, the pulse modulator modulates the bias of the base of a transistor or the gate of an MOS transistor inside the pulse modulator through corresponding load change to realize the change of the conduction time of the transistor or the MOS transistor, and adjusts the width (i.e. the duty ratio) of the pulse signal by controlling the change of the conduction time of the transistor or the MOS transistor. The microprocessor in the pulse modulator can store a preset program to control the pulse modulator to adjust the width of the pulse. The voltage controller 2, which is a pulse modulator, is connected to the output rectifying circuit 1 so that the voltage controller 2 can adjust the output voltage V of the output terminal of the output rectifying circuit 1outHigh and low. Of course, the voltage controller 2 may be other types of devices, and may be designed as required as long as it can control the output voltage VoutThe height of (2) is not limited herein.
Optionally, in the above overcurrent protection device provided in this embodiment, the voltage controller 2 may include a plurality of pins, and the plurality of pins may be connected to a lead of an external component, receive a signal (or a voltage) transmitted by the external component, and also transmit the signal to the external component. Here, the voltage controller 2 is described by taking an example in which 5 pins are included, and the 5 pins of the voltage controller 2 are a first pin 01, a second pin 02, a third pin 03, a fourth pin 04, and a fifth pin 05, respectively. The specific design may be as required, and is not limited herein.
Optionally, in the above overcurrent protection device provided in this embodiment, the device includes a first power supply voltage terminal E1And a second supply voltage terminal E2External elements connected to the first power supply voltage terminal E1Has the same reference potential, and an external element is connected to a second power supply voltage terminal E2Have the same reference potential.
Alternatively, as shown in fig. 2, in the above overcurrent protection device provided in the present embodiment, the output rectification circuit 1 may include a transformer T1Transformer T1Can include multiple types of transformers, the utility model discloses to transformer T among output rectifier circuit 11The specific structure of (a) is not limited. The present embodiment uses a transformer T1Comprises a first winding n1The secondary side comprises a second winding n2And a third winding n3For example, the second winding n is illustrated2Is an auxiliary winding.
In particular, a first winding n1The same name terminal of the circuit receives an external voltage VinFirst winding n1 ofThe different name terminal is connected to the voltage controller 2, specifically the first winding n1May be connected to the second pin 02 of the voltage controller 2. A second winding n2End of same name and second power voltage end E2Connected, second winding n2Is connected to the voltage controller 2, in particular the second winding n2Can be connected to the third pin 03 of the voltage controller 2, and the operating voltage V of the voltage controller 2CCBy a transformer T1Through a second winding n2Provided is a method. Third winding n3Is connected to the voltage feedback circuit 3, and a third winding n3Is coupled to the load. External voltage V being a DC high voltageinThrough a transformer T1After converting into output voltage of DC low voltage VoutTo a load.
Further, as shown in fig. 2, in the present embodimentIn the above overcurrent protection device, the output rectification circuit 1 may further include a synchronous rectification sub-circuit and an eighth resistor R8. The synchronous rectifier sub-circuit comprises a fourth capacitor C4And a third diode D3A third diode D3Is connected to the voltage controller 2, in particular a third diode D3May be connected to a third pin 03 of the voltage controller 2, a third diode D3Second terminal of and second winding n2The different name ends are connected. Fourth capacitor C4First terminal and third diode D3Is connected to a fourth capacitor C4Second terminal of (E) is connected to a second power supply voltage terminal E2. The synchronous rectifier circuit is connected with the second winding n2And a voltage controller 2 for applying an external voltage VoutRectifying to obtain external voltage VoutConverted into the operating voltage V of the voltage controller 2CCAnd the working voltage V is adjustedCCVia the third pin 03 of the voltage controller 2. To prevent this in the synchronous rectifier sub-circuit, a third diode D3Is too high, and thus connects the synchronous rectifier sub-circuit as a transformer T1On the second winding of the auxiliary winding. Operating voltage V of voltage controller 2CCSatisfies the following conditions:
further, as shown in FIG. 2, an eighth resistor R8Is connected to the first winding n1Between the dotted terminal of (1) and the first pin 01 of the voltage controller 2, an external voltage VinAfter being input into the over-current protection device, the over-current protection device passes through an eighth resistor R8For the fourth capacitor C in the synchronous rectifier sub-circuit4Charging is carried out when the fourth capacitor C4When the voltage reaches the voltage which can drive the MOS tube in the voltage controller 2 to be opened, the transformer T1The operation is started to increase the reliability of the overcurrent protection device provided by the present embodiment.
Alternatively, as shown in fig. 2, in the above overcurrent protection device provided in this embodiment, the output rectification circuit 1 may further include a smoothing rectifierA filter rectifier sub-circuit connected between the load and the transformer T1Third winding n3Between, an external voltage VinFor passing through transformer T1Output voltage V converted into low-voltage direct currentoutOutput voltage VoutAnd filtering and removing impurities by a filtering rectifier sub-circuit, and transmitting to a load. The filter rectifier sub-circuit can make the output voltage VoutSmoother and more stable. The filter-rectifier sub-circuit applied in this embodiment may include various types of rectifier circuits, and the filter-rectifier sub-circuit is a pi-type filter-rectifier sub-circuit as an example for description.
Further, as shown in fig. 2, in the above-mentioned overcurrent protection device provided in this embodiment, if the smoothing rectifier sub-circuit in the output rectification circuit 1 includes a pi-type smoothing rectifier sub-circuit, the pi-type smoothing rectifier sub-circuit may include a fourth diode D4A first inductor L1A fifth capacitor C5A sixth capacitor C6A seventh capacitor C7A ninth resistor R9。
In particular, the fourth diode D4First terminal and transformer T1Third winding n3The different name ends are connected. First inductance L1First terminal and fourth diode D4Is connected to the second terminal of the first inductor L1Is connected to a load. Sixth capacitor C6Is connected to the first inductor L1And a fourth diode D4Between, a sixth capacitance C6A second terminal connected to the voltage feedback circuit 3, a sixth capacitor C6And a detection resistor R in the voltage feedback circuit 3ZIs connected to the first terminal of the first capacitor, and a sixth capacitor C6The second terminal of the first power supply voltage terminal. Seventh capacitance C7First terminal and first inductor L1Is connected to the second terminal of the seventh capacitor C7Is connected to the voltage feedback circuit 3, in particular a seventh capacitor C7And a detection resistor R in the voltage feedback circuit 3ZAre connected to each other. Fifth capacitor C5And a ninth resistor R9Series, series circuit (C)5+R9) Are connected at both ends toFourth diode D4At both ends of the same. The pi-type filter rectifier circuit can filter the output voltage VoutNoise of (2) to make the output voltage VoutSmoother and more stable. Output voltage VoutSatisfies the following conditions:
optionally, as shown in fig. 2, in the over-current protection device provided in this embodiment, the voltage feedback circuit 3 specifically includes a detection resistor RZAn operational amplifier circuit 31 and an optical coupler circuit 32.
Specifically, the detection resistor RZIs connected to the output rectifying circuit 1, and detects the resistance RZIs coupled to the load and the other end of the load is grounded. Specific detection resistor RZThe output rectifying circuit 1 is connected by a detection resistor RZAnd a sixth capacitor C6Is connected to the second terminal of the detection resistor RZAnd the other end of the capacitor C and a seventh capacitor C7Are connected to each other. External voltage VinAfter passing through a transformer T1Primary side (first winding n)1) Then, the flow path of the working current is: transformer T1Third winding n3Synonym terminal → fourth diode D4→ first inductance L1→ load → sense resistor RZ→ transformer T1Third winding n3The same name end of (1). Thus, the current flows through the detection resistor RZThe current of the load is the same as the current flowing through the load, if the current flowing through the load is suddenly increased, the load voltage is also increased correspondingly, and meanwhile, the detection resistor RZThe current of (2) is increased correspondingly, i.e. the detection resistance R is increasedZIs increased, and thus, the resistance R is detectedZThe voltage variation degree of the load is the same as that of the load, as long as the detection resistor R is detectedZThe voltage change of the load, that is, the current flowing through the load, can be known. Operational amplifier circuit 31 and detection resistor RZConnected, the operational amplifier circuit 31 is used for detecting the detection resistor RZAnd amplifying the voltage variation of the detection resistor to protect the over-currentThe protection device is more sensitive to changes in load voltage, increasing the reliability of the overcurrent protection device. The optical coupler sub-circuit 32 is connected between the voltage controller 2 and the operational amplifier sub-circuit 31, the optical coupler sub-circuit 32 can isolate signals of an output end and an input end of the optical coupler sub-circuit, interference immunity of the overcurrent protection device is increased, reliability of detected load voltage change can be improved, the optical coupler sub-circuit 32 feeds back the detected load voltage change to the voltage controller 2, and the voltage controller 2 adjusts output voltage V according to the fed load voltage changeoutHigh and low.
Further, as shown in fig. 2, in the above overcurrent protection device provided in this embodiment, the operational amplifier circuit 31 may include a first transistor S1A first resistor R1A second resistor R2A first diode D1A first capacitor C1A second capacitor C2A third resistor R3Comparator FCA fourth resistor R4A second diode D2A third capacitor C3A fifth resistor R5A sixth resistor R6。
Specifically, the first triode S1Is connected to the optical coupler circuit 32, a first triode S1Is connected to a first power supply voltage terminal E1Upper, the first triode S1Base and second resistor R2A first diode D1Comparator FCThe output ends of the first and second triodes are sequentially connected in series, namely the first triode S1Base and second resistor R2Is connected to the first terminal of the first resistor R, and a second resistor R2Second terminal and first diode D1Are connected to a first terminal of a first diode D1Second terminal of and comparator FCAre connected with each other. A fourth resistor R4Is connected to the comparator FCOn the positive (+) terminal of the first resistor, a fourth resistor R4Second terminal and detection resistor RZIs connected to the second terminal of the fifth resistor R5Is connected to the comparator FCAt the negative (-) terminal of (3), a fifth resistance R5Second terminal and sixth resistor R6Is connected to the first terminal of the sixth resistor R6Is connected to the first supply voltage terminal E1The above. Second diode D2First terminal and fourth resistor R4Is connected to a second terminal of a second diode D2Is connected to the first supply voltage terminal E1The above. Third capacitor C3First terminal and fourth resistor R4Is connected to a second terminal of a third capacitor C3Is connected to the first supply voltage terminal E1The above.
Further, in the operational amplifier sub-circuit 31, the first resistor R1First terminal of and a first triode D1Is connected to the base of a first resistor R1Second terminal of the first power supply voltage terminal E1The above. A first capacitor C1And a third resistor R3In series, and a first capacitor C1And a third resistor R3A branch formed by series connection with a second capacitor C2Connected in parallel to form an operational amplifier feedback sub-circuit, the first end of which is connected to a comparator FCOn the output terminal of the operational amplifier feedback sub-circuit, the second terminal of the operational amplifier feedback sub-circuit is connected with the comparator FCOn the negative end of (c).
In addition, the comparator FCComprises an input terminal, an output terminal, a comparator FCIncludes a positive (+) terminal and a negative (-) terminal.
Further, as shown in fig. 2, in the above overcurrent protection device provided in the present embodiment, the optical coupler sub-circuit 32 includes an input terminal and an output terminal. Specifically, the input terminal of the optical coupler sub-circuit 32 includes a light emitting diode DgAnd a seventh resistor R7Light emitting diode DgAnd a seventh resistor R7Are connected in series to form a light emitting diode DgConnected to the operational amplifier circuit 31, in particular, a light emitting diode DgAnd the first transistor S in the operational amplifier sub-circuit 311Is connected to the collector of the collector. The output of the optical coupler circuit 32 comprises a photo transistor SgPhoto transistor SgIs connected with a voltage controller 2, a specific phototriode SgIs connected to the fourth pin 04 of the voltage controller 2, and the phototransistor SgIs connected to a second supply voltage terminal E2The above. Detecting electricityResistance RZThe voltage variation signal is amplified by the operational amplifier circuit 32 and then passes through the light emitting diode DgTransmitted to the optical coupler sub-circuit 32, the light emitting diode DgConverting the electrical signal into an optical signal, phototriodes SgSensing the light emitting diode DgThen converts the optical signal into an electrical signal, and feeds the electrical signal back to the voltage controller 2, i.e. the detection resistor RZThe detected voltage change of the load is fed back to the voltage controller 2. By means of the signal transmission mode, the anti-interference performance of signal transmission can be effectively improved, and therefore the reliability of the overcurrent protection device provided by the embodiment is improved.
In summary, the voltage feedback circuit 3 includes an operational amplifier sub-circuit 31 and an optical coupler sub-circuit 32, and a detection resistor R in the operational amplifier sub-circuit 31ZIs connected to a comparator FCIf the load voltage rises, the detection resistor R is the same as the load voltage changeZWill also increase, and the comparator F will increaseCThe voltage of the positive terminal of the operational amplifier is increased, and after the gain of the operational amplifier feedback sub-circuit, the comparator FCThe voltage at the output end is increased, and the increased voltage passes through the first resistor R1And a second resistor R2After the voltage division, the first triode S is enabled1The conduction degree of the first triode S is deepened1And the collector of the light emitting diode D in the optical coupler circuit 32gAre connected so as to flow through the light emitting diode DgThe current of the photo-coupler circuit 32 increases, and the photo-transistor S in the photo-coupler circuit 32 is operated by the photo-electricity of the photo-coupler circuit 32gThe conduction degree of the transistor is also increased, so that the phototriode S is used for controlling the transistorgThe current signal fed back to the voltage controller 2 is increased correspondingly, and after the voltage controller 2 receives the change signal of the load voltage fed back by the voltage feedback circuit 3, the width of the pulse signal is adjusted according to the change signal of the fed back load voltage, so that the output voltage V of the output end of the output rectification circuit 1 can be reducedout. Through the feedback mode, the overcurrent protection device provided by the embodiment can quickly and accurately adjust the output voltage, limit the current passing through the load and furtherThereby avoiding the load from being damaged due to the overlarge current passing through the load.
Correspondingly, the utility model discloses still provide an overcurrent protection system, including the overcurrent protection device of above-mentioned embodiment. If the overcurrent protection system provided in this embodiment is configured such that the overcurrent protection device is disposed between the load and the external voltage, and the external voltage needs to be output to the load after passing through the overcurrent protection device, in the overcurrent protection device provided in this embodiment, because the voltage feedback circuit 3 is disposed in the device, the voltage feedback circuit 3 is coupled to the load, and detects the load voltage change in real time and feeds the load voltage change back to the voltage controller 2, if the external voltage V is detected, the voltage feedback circuit 3 is coupled to the loadinWhen the load voltage suddenly increases due to an excessive current, the voltage feedback circuit 3 will feed back the detected load voltage variation to the voltage controller 2, and the voltage controller 2 will output the output voltage V according to the load voltage variation fed back by the voltage feedback circuit 3outAmplitude modulation, i.e. modulating the output voltage VoutReduced, reduced output voltage VoutThen the output voltage is rectified by the output rectifying circuit 1 and transmitted to the load, so that the output voltage can be quickly and accurately adjusted, the current passing through the load is limited, and the load is prevented from being damaged due to overlarge passing current.
It is to be understood that the above embodiments are merely exemplary embodiments that have been employed to illustrate the principles of the present invention, and that the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.
Claims (9)
1. An overcurrent protection device, comprising:
the input end of the output rectifying circuit receives external voltage, and the output end of the output rectifying circuit is coupled with a load and used for rectifying the external voltage received by the input end and transmitting the rectified external voltage to the load;
the voltage controller is connected with the output rectifying circuit and used for adjusting the output voltage of the output end;
the voltage feedback circuit is connected with the output rectifying circuit and the voltage controller, is coupled with the load, and is used for detecting the voltage change of the load and feeding back the voltage change of the load to the voltage controller so that the voltage controller adjusts the output voltage of the output end according to the fed back voltage change of the load; wherein,
the voltage feedback circuit specifically comprises:
one end of the detection resistor is connected with the output rectifying circuit, the other end of the detection resistor is coupled with the load, and the voltage change degree of the detection resistor is the same as that of the load;
the operational amplifier sub-circuit is connected with the detection resistor and is used for detecting the voltage change of the detection resistor and amplifying the voltage change of the detection resistor;
and the optical coupler sub-circuit is connected between the voltage controller and the operational amplifier sub-circuit, is used for improving the reliability of the detected voltage change and feeds the detected voltage change back to the voltage controller.
2. The overcurrent protection device of claim 1, wherein the operational amplifier subcircuit comprises: the circuit comprises a first triode, a first resistor, a second resistor, a first diode, a first capacitor, a second capacitor, a third resistor, a comparator, a fourth resistor, a second diode, a third capacitor, a fifth resistor and a sixth resistor; wherein,
the collector of the first triode is connected with the optical coupler circuit, and the base of the first triode is sequentially connected with the second resistor, the first diode and the output end of the comparator in series;
the first end of the first resistor is connected with the base electrode of the first triode, and the second end of the first resistor is connected with a first power supply voltage end;
the first capacitor is connected with the third resistor in series and is connected with the second capacitor in parallel to form an operational amplifier feedback sub-circuit, the first end of the operational amplifier feedback sub-circuit is connected with the output end of the comparator, and the second end of the operational amplifier feedback sub-circuit is connected with the negative end of the comparator;
the first end of the fourth resistor is connected to the positive end of the comparator, and the second end of the fourth resistor is connected to the detection resistor, the second diode and the third capacitor;
and the first end of the fifth resistor is connected to the negative end of the comparator, and the second end of the fifth resistor is connected with the sixth resistor.
3. The overcurrent protection device of claim 1 wherein the optical coupler subcircuit comprises an input and an output;
the input end of the optical coupling sub-circuit comprises a light emitting diode and a seventh resistor which are connected in series, and the light emitting diode is connected with the operational amplifier sub-circuit;
the output end of the optical coupler sub-circuit comprises a phototriode, and the collector electrode of the phototriode is connected with the voltage controller.
4. The overcurrent protection apparatus as set forth in claim 1, wherein the voltage controller comprises a pulse width modulator for generating a pulse signal, and the output voltage of the output terminal is controlled by adjusting a width of the pulse signal.
5. The overcurrent protection device as recited in claim 1, wherein the output rectifier circuit comprises a transformer, a primary side of the transformer comprising a first winding, a secondary side comprising a second winding and a third winding; wherein,
the homonymous terminal of the first winding receives external voltage, and the synonym terminal of the first winding is connected to the voltage controller;
the synonym end of the second winding is connected with the voltage controller to provide working voltage for the voltage controller;
and the dotted terminal of the third winding is connected with the voltage feedback circuit.
6. The overcurrent protection device as set forth in claim 5, wherein the output rectifying circuit further comprises a synchronous rectifier sub-circuit and an eighth resistor, the synchronous rectifier sub-circuit being connected between the second winding and the voltage controller for rectifying an external voltage to convert the external voltage into an operating voltage of the voltage controller;
the synchronous rectifier sub-circuit comprises a fourth capacitor and a third diode, wherein the first end of the third diode is connected with the voltage controller, the second end of the third diode is connected with the synonym end of the second winding, the first end of the fourth capacitor is connected with the first end of the third diode, and the second end of the fourth capacitor is connected with the second power supply voltage end;
the eighth resistor is connected between the dotted terminal of the first winding and the voltage controller.
7. The overcurrent protection device of claim 5 wherein the output rectification circuit further comprises a smoothing rectifier sub-circuit connected between the load and the third winding.
8. The overcurrent protection device of claim 7 wherein the filter-rectifier subcircuit comprises a pi-type filter-rectifier subcircuit, the pi-type filter-rectifier subcircuit comprising: the fourth diode, the first inductor, the fifth capacitor, the sixth capacitor, the seventh capacitor and the ninth resistor; wherein,
the first end of the fourth diode is connected with the different name end of the third winding;
the first end of the first inductor is connected with the second end of the fourth diode, and the second end of the first inductor is connected with the load;
the first end of the sixth capacitor is connected between the first inductor and the fourth diode, and the second end of the sixth capacitor is connected with the voltage feedback circuit;
the first end of the seventh capacitor is connected with the second end of the first inductor, and the second end of the seventh capacitor is connected with the voltage feedback circuit;
and the fifth capacitor is connected with the ninth resistor in series, and two ends of the circuit after series connection are connected to two ends of the fourth diode.
9. An overcurrent protection system comprising an overcurrent protection device as claimed in any one of claims 1 to 8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922176892.1U CN211377578U (en) | 2019-12-05 | 2019-12-05 | Overcurrent protection device and system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201922176892.1U CN211377578U (en) | 2019-12-05 | 2019-12-05 | Overcurrent protection device and system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112531639A (en) * | 2020-11-12 | 2021-03-19 | 深圳Tcl数字技术有限公司 | Overcurrent protection trigger circuit and device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112531639A (en) * | 2020-11-12 | 2021-03-19 | 深圳Tcl数字技术有限公司 | Overcurrent protection trigger circuit and device |
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