CN209313410U - A kind of overload protecting circuit of DC power supply - Google Patents

Abstract

The application provides a kind of overload protecting circuit of DC power supply, which includes: protection detection module, guard delay module and protection control module；The input terminal of the protection detection module is connect with power output end, and the output end of the protection detection module is connect with the guard delay module；The both ends of the guard delay module are separately connected the output end of the protection detection module and the control terminal of the protection control module；The both ends of the protection control module are respectively connected to low level and the power output end；Overload protecting circuit structure provided by the utility model is simple, and cost is reasonable, can effectively realize the overload protection of power output signal, and the overload protecting circuit of the utility model is versatile, facilitates the reliability for promoting power supply and the stable operation of power grid.

Description

Overload protection circuit of direct current power supply

Technical Field

The embodiment of the utility model provides a relate to the electronic circuit field, especially relate to a DC power supply's overload protection circuit.

Background

With the rapid development of modern switching power supply technology, the demand for power supply of the power grid gradually tends to diversify, the power efficiency continuously breaks through the limit, based on various types of power supplies, when external faults occur, the output power overload of the power supply can cause power supply faults and potential safety hazards, especially for power supplies with larger output power, such as a power supply with a single power supply output power of more than 500W and a single output current of more than 50A, once the external faults occur, considerable destructive power can be generated, and the manpower and material consumption of perfect protection measures, such as primary level overcurrent protection, primary level overvoltage and undervoltage protection, overheating protection, personal safety protection and the like, are too high; therefore, power supply overload protection technology is indispensable.

In the prior art, a common protection scheme is to monitor a power signal output by a power supply and start protection once the power signal exceeds a normal range. In practical application, power signals of a power supply fluctuate, which may cause frequent actions of a protection circuit and excessively high false action probability, greatly shortens the service life of circuit devices, and has quite high cost.

SUMMERY OF THE UTILITY MODEL

The application provides a DC power supply's overload protection circuit, this DC power supply's overload protection circuit is used for solving current overload protection scheme probability of maloperation too high, and protection component life is short and the cost consumes too much problem, promotes DC power supply's overload protection technical reliability based on the technical scheme of this application, controls the cost of power overload protection operation simultaneously.

The application provides DC power supply's overload protection circuit includes: the device comprises a protection detection module, a protection delay module and a protection control module; wherein,

the input end of the protection detection module is connected with the power output end, and the output end of the protection detection module is connected with the protection delay module and used for outputting a protection starting signal or a protection releasing signal to the protection delay module according to a power output signal of the current power output end;

the two ends of the protection delay module are respectively connected with the output end of the protection detection module and the control end of the protection control module and used for transmitting the received protection starting signal or protection releasing signal to the control end of the protection control module in a delayed manner;

and two ends of the protection control module are respectively connected to the low level and the power output end and are used for being switched on or switched off under the control of the protection starting signal or the protection releasing signal so as to start or release the protection.

Further, the overload protection circuit further includes: the filtering module is connected between the power output end and the protection detection module;

and the filtering module is used for filtering the power output signal and transmitting the filtered power output signal to the protection detection module.

Further, the filtering module includes: a filter resistor and a filter capacitor;

one end of the filter resistor is connected with the output end of the power supply, and the other end of the filter resistor is connected with the input end of the protection detection module;

one end of the filter capacitor is connected with the other end of the filter resistor, and the other end of the filter capacitor is grounded.

The protection detection module includes: a first comparator and a first signal providing module;

the first signal providing module is used for providing a first predetermined signal;

the positive input end of the first comparator is connected to the power output end, the negative input end of the first comparator is connected to the first signal providing module, and the first signal providing module is used for outputting a protection starting signal when the power output signal value is larger than or equal to the first preset signal value, and outputting a protection releasing signal when the power output signal value is smaller than the first preset signal value.

Further, the first signal providing module includes: a first resistor and a second resistor;

one end of the first resistor is connected with a high level, and the other end of the first resistor is connected with the negative input end of the first comparator and one end of the second resistor;

the other end of the second resistor is grounded.

The protection delay module includes: a first delay resistor and a delay capacitor;

one end of the first delay resistor is connected with the output end of the protection detection module, and the other end of the first delay resistor is connected with the control end of the protection control module and one end of the delay capacitor;

the other end of the delay capacitor is grounded.

Further, the protection delay module further comprises: a first diode and a second delay resistor connected between the first delay resistor and the delay capacitor;

one end of the second delay resistor is connected with the other end of the first delay resistor, and the other end of the second delay resistor is connected with one end of the delay capacitor;

the anode of the first diode is connected with one end of the delay capacitor, and the cathode of the first diode is connected with the other end of the first delay resistor.

Further, the protection delay module further comprises: the second comparator, the third delay resistor, the second diode and the second signal providing module are positioned between the first delay resistor and the protection control module;

the second signal providing module is used for providing a second predetermined signal;

the positive input end of the second comparator is connected with the other end of the first delay resistor, the negative input end of the second comparator is connected with the second signal providing module, and the output end of the second comparator is connected with the control end of the protection control module;

the anode of the second diode is connected with the output end of the second comparator, and the cathode of the second diode is connected with one end of the third delay resistor;

the other end of the third delay resistor is connected with the other end of the first delay resistor.

Further, the second signal providing module includes: a third resistor and a fourth resistor;

one end of the third resistor is connected with a high level, and the other end of the third resistor is connected with the negative input end of the second comparator and one end of the fourth resistor;

the other end of the fourth resistor is grounded.

The protection control module includes: the control end of the protection control module is a base electrode of the triode, and two ends of the protection control module are an emitting electrode and a collecting electrode of the triode;

and the emitter of the triode is connected to the low level, and the collector of the triode is connected to the power output end.

Further, the protection control module further includes: a fifth resistor and a sixth resistor;

one end of the fifth resistor is connected with the output end of the protection delay module, and the other end of the fifth resistor is connected with the base electrode of the triode and one end of the sixth resistor;

the other end of the sixth resistor is connected with the emitting electrode of the triode.

Further, the protection control module further includes: a third diode connected between the power output terminal and the triode;

the anode of the third diode is connected with the power output end, and the cathode of the third diode is connected with the collector of the triode.

The overload protection circuit further includes: the soft start module is connected between the power output end and the power supply device;

and the soft start module is used for transmitting the power output signal output by the power output end to the supplied power equipment in a delayed manner.

Further, the soft start module comprises: a soft start resistor and a soft start capacitor;

one end of the soft start capacitor is connected with the power output end and one end of the soft start capacitor, and the other end of the soft start capacitor is grounded;

the other end of the soft start resistor is connected to the powered device.

Further, the soft start module further comprises: a fourth diode and a fifth diode connected between the power supply output terminal and the soft start capacitor;

the anode of the fourth diode is connected with the power output end, and the cathode of the fourth diode is connected with one end of the soft start capacitor and the anode of the fifth diode;

and the cathode of the fifth diode is connected with the other end of the soft start resistor.

The application provides a DC power supply's overload protection circuit, this DC power supply protection circuit includes: the device comprises a protection detection module, a protection delay module and a protection control module; this application protection detection module detects power output signal, for protection delay module provides protection start signal and protection and removes the signal, protection delay module transmits received signal delay for protection control module to control protection control module starts or closes the protection action. The protection detection module that technical scheme of this application set up has guaranteed the accuracy nature of protection action, realizes overload protection based on protection delay module and protection control module, has overcome among the prior art fault probability height, and the short defect of device life has promoted power and protection circuit's reliability under the prerequisite of effectively realizing power overload protection, helps promoting the steady operation of electric wire netting.

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, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of an overload protection circuit of a dc power supply according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of an overload protection circuit of a dc power supply according to a second embodiment of the present invention;

fig. 3 is a schematic structural diagram of an overload protection circuit of a dc power supply according to a third embodiment of the present invention;

fig. 4 is a schematic circuit structure diagram of a filter module of an overload protection circuit of a dc power supply according to a fourth embodiment of the present invention;

fig. 5 is a schematic circuit structure diagram of a protection detection module of an overload protection circuit of a dc power supply according to a fifth embodiment of the present invention;

fig. 6 is a schematic circuit structure diagram of a protection delay module of an overload protection circuit of a dc power supply according to a sixth embodiment of the present invention;

fig. 7 is a schematic circuit structure diagram of a protection delay module of an overload protection circuit of a dc power supply according to a seventh embodiment of the present invention;

fig. 8 is a schematic circuit structure diagram of a protection delay module of an overload protection circuit of a dc power supply according to an eighth embodiment of the present invention;

fig. 9 is a schematic circuit structure diagram of a protection control module of an overload protection circuit of a dc power supply according to a ninth embodiment of the present invention;

fig. 10 is a schematic circuit diagram of a protection control module of an overload protection circuit of a dc power supply according to a tenth embodiment of the present invention;

fig. 11 is a schematic structural diagram of an overload protection circuit of a dc power supply according to an eleventh embodiment of the present invention;

fig. 12 is a schematic circuit structure diagram of a soft start module of an overload protection circuit of a dc power supply according to an eleventh embodiment of the present invention;

fig. 13 is a schematic circuit structure diagram of a soft start module of an overload protection circuit of a dc power supply according to a twelfth embodiment of the present invention;

fig. 14 is a schematic structural diagram of an overload protection circuit of a dc power supply according to a fourteenth embodiment of the present invention;

description of reference numerals:

r63-filter resistance; c18-filter capacitance;

U1A — first comparator; r64 — first resistance;

r65 — second resistance; r66 — first delay resistance;

c19-delay capacitance; r70 — second delay resistance;

d6 — first diode; U1B — second comparator;

d4 — second diode; r67-third delay resistance;

r71 — third resistance; r72-fourth resistor;

q1-triode; r68-fifth resistor;

r69-sixth resistance; d5 — third diode;

R62-Soft Start resistance; c16 — soft start capacitance;

d2 — fourth diode; d3-fifth diode.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

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

It should be noted that the following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

Fig. 1 is a schematic structural diagram of an overload protection circuit of a dc power supply according to an embodiment of the present disclosure; referring to the attached figure 1, the utility model provides a low, reasonable in design's of false action probability high accuracy power overload protection circuit, the overload protection circuit of this power includes: the device comprises a protection detection module, a protection delay module and a protection control module; wherein,

the input end of the protection detection module is connected with the power output end, and the output end of the protection detection module is connected with the protection delay module and used for outputting a protection starting signal or a protection releasing signal to the protection delay module according to a power output signal of the current power output end;

the two ends of the protection delay module are respectively connected with the output end of the protection detection module and the control end of the protection control module and used for transmitting the received protection starting signal or protection releasing signal to the control end of the protection control module in a delayed manner;

and two ends of the protection control module are respectively connected to the low level and the power output end and are used for being switched on or switched off under the control of the protection starting signal or the protection releasing signal so as to start or release the protection.

In this application, each functional module can be connected through a wire, or can be connected through a copper bar or other methods, and this is not limited in this embodiment.

The protection control module is connected with the low level at one end and connected with the power output end at the other end, carries out protection after delaying on the received protection starting signal and carries out transmission after delaying on the received protection removing signal, and the purpose of protecting the power output is achieved.

In practical applications, the power output terminal may be located at a node capable of reflecting the power output signal or at an output terminal of a circuit or a component having an error amplification function, for example, an error amplifier output terminal in a power controller; fig. 2 shows a schematic structural diagram of an overload protection circuit of a dc power supply according to a second embodiment of the present application, and it can be known from fig. 2 that: in the embodiment, OUT-AV is a power output voltage sampling signal, A1 is an error amplifier inside a power controller, and A2 is a pulse width regulator inside the power controller; the output signal of the power supply adopts the output signal of an error amplifier of the power supply controller, is also the input signal of the pulse width regulator and represents the pulse width of the power supply during actual work; the magnitude of the pulse width is closely related to the load of the power supply, and the analog quantity can effectively represent the actual output power of the power supply.

The current overload protection circuit samples the output voltage and current of a power supply, calculates various output power indexes through a cpu, and then outputs a protection instruction for protection; or the IV amount is analog multiplied using a multiplier and then protected. Compared with the prior art, the scheme uses the signal which is output by the output port of the error amplifier A1 and can truly reflect the power output power as the monitored power output signal to execute the corresponding protection action, thereby simplifying the circuit structure, reducing the operation complexity and the influence of interference factors, improving the response speed of the overload protection circuit, and simultaneously controlling the cost of the protection circuit within a reasonable range.

The embodiment adopts the pulse width signal of error amplifier A1 output as the power output signal, the power output end that is used for gathering the power output signal with this scheme sets up the output port at error amplifier A1, detect the signal and transmit to protection delay module and protection control module through the protection detection module and realize power overload protection, realize optimizing from the root of input signal, make the technical scheme of this application can be applied to various power structures that have overload protection demand, the accuracy and the commonality of power overload protection circuit have been guaranteed.

According to the above embodiments, in the present application, the protection detection module outputs the protection start signal or the protection release signal to the protection delay module, and the protection delay module executes the delay protection start operation or the delay protection release operation according to the received protection start signal or the protection release signal, so that the output signal of the protection detection module is the key for accurately protecting the overload protection circuit, and therefore, in order to ensure the function (reliability) of the overload protection circuit, a preprocessing structure, such as a filter circuit, for eliminating the impurity signal in the power output signal may be provided between the power output terminal and the protection detection module; fig. 3 shows a schematic structural diagram of an overload protection circuit of a dc power supply according to a third embodiment of the present application, and it can be known from fig. 3 that: the overload protection circuit of this embodiment further includes: the filtering module is connected between the power output end and the protection detection module;

the filtering module is used for filtering the power output signal and transmitting the filtered power output signal to the protection detection module, and the filtering module is arranged before the protection detection module to filter interference signals in the power output signal, so that a foundation is laid for improving the accuracy of power overload protection.

In practical applications, the filtering module may be a circuit structure capable of filtering the power output signal, for example, an RC filter circuit or an LC filter circuit. Correspondingly, optionally, fig. 4 shows a schematic circuit structure diagram of a filter module of an overload protection circuit of a dc power supply according to a fourth embodiment of the present application, and it can be known with reference to fig. 4 that: the filtering module of this embodiment includes: a filter resistor R63 and a filter capacitor C18;

one end of the filter resistor R63 is connected with the output end of the power supply, and the other end of the filter resistor R63 is connected with the input end of the protection detection module;

one end of the filter capacitor C18 is connected with the other end of the filter resistor R63, and the other end of the filter capacitor C18 is grounded. The filter resistor of the second embodiment of the application carries out filtering operation on the power output signal through the filter resistor R63 and the filter capacitor C18, and then the power output signal is input into the protection detection module to be detected and subsequently protected, the RC circuit structure with the simple structure is adopted in the second embodiment of the application, and the accuracy of the detection result of the protection detection module is guaranteed on the basis of control cost.

In an actual working condition, the protection detection module may be a circuit or an element capable of detecting a magnitude of a power output signal, and is correspondingly optional, fig. 5 shows a schematic circuit structure diagram of the protection detection module of the overload protection circuit of the dc power supply according to a fifth embodiment of the present application, and it can be known with reference to fig. 5 that: the protection detection module of this embodiment includes: a first comparator U1A and a first signal providing module;

the first signal providing module is used for providing a first predetermined signal;

the positive input end of the first comparator U1A is connected to the power output end, the negative input end is connected to the first signal providing module, and is configured to output a protection start signal when the power output signal value is greater than or equal to the first predetermined signal value, and output a protection release signal when the power output signal value is less than the first predetermined signal value.

The first comparator compares the received power output signal of the positive input end with a first preset signal value of the negative reference end, if the power output signal value is larger than or equal to the first preset signal value, a protection starting signal is output to the protection delay module, and if the power output signal value is smaller than the first preset signal value, a protection releasing signal is output to the protection delay module; the value of the first predetermined signal is set according to the parameters of the power supply in the actual working condition.

In this embodiment, the first signal providing module may be generated by dividing a voltage of a power supply of the circuit, or may be dynamically set by an additionally configured intelligent controller through DA setting, and in this embodiment, the first signal providing module includes: a first resistor R64 and a second resistor R65;

one end of the first resistor R64 is connected with a high level, and the other end of the first resistor R64 is connected with a negative input end of the first comparator U1A and one end of a second resistor R65; the other end of the second resistor R65 is grounded.

The protection delay module is arranged to transmit the detected power output signal to the protection detection module to realize power overload protection, so that accurate execution of protection action is guaranteed, and data support is provided for orderly operation of other functional modules of the power overload protection circuit.

According to another embodiment, the protection delay module of the present application is used for delaying transmission of a protection start signal or a protection release signal of a protection detection module output, in practical applications, a circuit structure or an element having a delay circuit for transmitting a signal may be adopted, fig. 6 shows a schematic circuit structure diagram of the protection delay module of an overload protection circuit of a dc power supply provided in a sixth embodiment of the present application, and as can be seen with reference to fig. 6, the protection delay module of the present embodiment includes: a first delay resistor R66 and a delay capacitor C19;

one end of the first delay resistor R66 is connected with the output end of the protection detection module, and the other end of the first delay resistor R66 is connected with the control end of the protection control module and one end of the delay capacitor C19;

the other end of the delay capacitor C19 is grounded, in this embodiment, the delay capacitor C19 is charged through the first delay resistor R66 connected to the output end of the protection detection module, so as to achieve the purpose of further transmitting the signal of the delay circuit, and in the technical scheme, the signal charged to the delay capacitor C19 can be set to reach a certain threshold value and then transmitted to the circuit control module; when the external load is abnormal, the high-pulse-width signal of the power output end can be effectively delayed, the power overload protection is realized by combining the protection control module, software participation is not needed, the structure is simple, the influence of transient disturbance is not needed to be considered, and the reliability is high.

Based on the above embodiments, in order to avoid the overvoltage problem occurring in the protection delay module to damage the electrical component and ensure the stability of the protection circuit, an element or a circuit structure that prevents the overvoltage from occurring or implements the overvoltage protection, such as a load element or a diode of the reverse link 2, may be provided, and fig. 7 illustrates a schematic circuit structure diagram of the protection delay module of the overload protection circuit of the dc power supply according to a seventh embodiment of the present application, and it can be known with reference to fig. 7: correspondingly optionally, the protection delay module of this embodiment further includes: a first diode D6 and a second delay resistor R70 connected between the first delay resistor R66 and a delay capacitor C19; the first diode is used for performing overvoltage protection on the circuit, and the circuit is prevented from being damaged due to overvoltage abnormity.

One end of the second delay resistor R70 is connected to the other end of the first delay resistor R66, and the other end of the second delay resistor R70 is connected to one end of the delay capacitor C19;

the anode of the first diode D6 is connected with one end of the delay capacitor C19, and the cathode of the first diode D6 is connected with the other end of the first delay resistor R66;

the power overload signal output by the protection detection module is used for the protection delay module, the delay capacitor C19 is charged through the first delay resistor R66 and the second delay resistor R70 according to the technical scheme of the embodiment, and the power overload signal is transmitted to the protection control module after the signal of the delay capacitor C19 is charged to a set threshold value, so that the transmission of the power overload signal in the circuit is effectively delayed, the circuit load in the protection delay module is increased through the set second delay resistor R70, the effect of the protection circuit is achieved, meanwhile, the circuit can be timely protected once an overvoltage phenomenon occurs through the set first diode, and the reliability of the overload protection circuit is effectively improved through the conventional structure.

In practical applications, if only the circuit structure for delaying protection activation is set, although the transmission of the delay signal in the protection activation stage in the circuit can be effectively achieved, only one threshold parameter is set, the protection action is released once the signal is out of the overload range of the circuit signal, and if the circuit signal is in a floating state in a short period of time, the protection action is frequently started and released, so as to avoid the above phenomenon and reduce the loss of the elements in the overload protection circuit, a circuit structure with delay protection action release and a corresponding threshold parameter, such as a return circuit, may be set, fig. 8 shows a circuit structure schematic diagram of a protection delay module of the overload protection circuit of the dc power supply according to an eighth embodiment of the present application, and it can be known with reference to fig. 8: the protection delay module in this embodiment further includes: a second comparator U1B, a third delay resistor R67, a second diode D4 and a second signal providing module between the first delay resistor R66 and the protection control module;

the second signal providing module is used for providing a second predetermined signal;

the positive input end of the second comparator U1B is connected to the other end of the first delay resistor R66, the negative input end of the second comparator U1B is connected to the second signal providing module, and the output end of the second comparator U1B is connected to the control end of the protection control module;

the anode of the second diode D4 is connected to the output terminal of the second comparator U1B, and the cathode of the second diode D4 is connected to one end of the third delay resistor R67;

the other end of the third delay resistor R67 is connected with the other end of the first delay resistor R66;

the second signal providing module includes: a third resistor R71 and a fourth resistor R72;

one end of the third resistor R71 is connected with a high level, and the other end of the third resistor R71 is connected with the negative input end of the second comparator U1B and one end of the fourth resistor R72;

the other end of the fourth resistor R72 is grounded.

In this embodiment, a second comparator U1B, a second diode D4, and a third delay resistor R67 are provided, the protection control module and the output of the second comparator U1B form a new input channel, the positive feedback of the second diode D4 and the third delay resistor R67 of the protection delay module forms a one-way return difference, so that the load after the overload abnormity of the circuit is relieved is smaller than the load of the protection action, when the external load returns to normal and the overlarge load is changed into a proper load or the power failure occurs, the signal of the input end of the second comparator is improved compared with the overload abnormal signal, however, at this time, the protection operation is not released, the delay capacitor C19 and the circuit signal transmission are discharged through the first delay resistor R66 and the second delay resistor R70, when the delay capacitor C19 discharges until the signal is lower than the set release threshold parameter, the overload protection action is released, and the release threshold parameter can be set according to the current circuit power supply and the protection requirement; by adopting the technical scheme, the time for releasing the protection action is delayed based on double parameters, the period of the protection action (single time) is properly prolonged, the protection action is effectively prevented from being frequently started and released at the stage of unstable circuit signals, and the element loss probability of a protection delay module and a protection control module of the protection circuit is reduced; the overload protection period is from the beginning of the overload signal of the output power of the protection detection module to the end of the overload protection releasing action, so that the system oscillation caused by frequent actions is avoided.

In addition, the second signal providing module can be generated by adopting the power supply voltage division of the circuit, and can also be dynamically set by an additionally configured intelligent controller through DA setting, and the value of the second predetermined signal is set according to the value of the first predetermined signal and the user requirement. The embodiment realizes a simple and cheap analog circuit protection scheme without software participation based on the composite parameter of the first preset signal and the second preset signal, can effectively avoid the influence of frequent actions of the circuit on the reliability of a power supply, and avoids the further expansion of load faults.

In practical conditions, in order to perform the function of power overload protection, the protection control module may adopt an electrical element or structure having a function of selectively transmitting a signal, such as a triode, fig. 9 shows a schematic circuit structure diagram of the protection control module of the overload protection circuit of the dc power supply according to a ninth embodiment of the present application, and it can be known with reference to fig. 9: the protection control module in this embodiment includes: a triode Q1, wherein the control end of the protection control module is the base electrode of the triode Q1, and the two ends of the protection control module are the emitter and the collector of the triode Q1;

the emitter of the transistor Q1 is connected to the low level, and the collector of the transistor Q1 is connected to the power supply output terminal.

When the protection delay module outputs a protection starting signal to the protection control module, the protection control module connects the protection starting signal with a low level through the transmitting set, so that the abnormal power output signal is transmitted to the supplied power equipment in an interrupted manner; when the protection delay module outputs a protection release signal to the protection control module, the protection control module releases the current protection action, so that the power output end transmits a normal signal to the supplied power equipment, the signals received by the supplied power equipment are all signals meeting the power utilization standard of the supplied power equipment, and the protection of the supplied power equipment is effectively realized.

The scheme realizes overload protection through the controllable switch element, can further simplify the circuit structure, reduces the cost and improves the response speed.

Based on the protection control module of the above embodiment, in consideration of the possibility of overvoltage phenomenon of the circuit signal, an element or a circuit structure having a delay signal or implementing overvoltage protection may be provided in the protection control module, for example, a load is provided or a diode is added, fig. 10 shows a schematic circuit structure diagram of a protection delay module of an overload protection circuit of a dc power supply according to an embodiment of the present application, and it can be known with reference to fig. 10: correspondingly optionally, the protection control module of this embodiment further includes: a fifth resistor R68 and a sixth resistor R69;

one end of the fifth resistor R68 is connected with the output end of the protection delay module, and the other end of the fifth resistor R68 is connected with the base of the triode Q1 and one end of the sixth resistor R69;

the other end of the sixth resistor R69 is connected to the emitter of the transistor Q1.

The protection control module further includes: a third diode D5 connected between the power supply output terminal and the transistor Q1;

the anode of the third diode D5 is connected to the power output terminal, and the cathode of the third diode D5 is connected to the collector of the transistor Q1;

in this embodiment, the fifth resistor R68 connected to the output terminal of the protection delay module and the sixth resistor R69 connected to the emitter of the transistor Q1 can reduce the time from the protection delay module to the low level of the circuit signal, and the third diode D5 connected to the collector of the transistor can effectively protect the circuit, reduce the probability of circuit abnormality, and ensure the reliability of the overload protection circuit.

The output signals of the triode of the embodiment are connected through a plurality of logic outputs for low and action, so that an OC gate output structure is adopted, and in an overload protection period, the signals are transmitted to a low level to achieve the effect of protecting a power supply.

In an actual working condition, before the output voltage is not established, namely the output of the power supply is zero before the power supply is electrified, the output voltage of the power supply is quickly increased at the beginning of electrifying, the pulse width is suddenly increased, the overload protection circuit of the power supply can be caused to malfunction, in order to avoid the power supply overload protection circuit from influencing the service life of the protection circuit and the elements thereof, the cost is controlled, and an element or a circuit structure capable of relieving the pulse width mutation phenomenon of a signal during electrifying, such as an external load or a soft start structure, can be arranged at the output end of the; fig. 11 is a schematic structural diagram illustrating an overload protection circuit of a dc power supply according to an eleventh embodiment of the present application, and it can be known with reference to fig. 11 that: the overload protection circuit in this embodiment further includes: the soft start module is connected between the power output end and the power supply device;

fig. 12 is a schematic structural diagram illustrating an overload protection circuit of a dc power supply according to an eleventh embodiment of the present application, and it can be known with reference to fig. 12 that: the soft start module includes: a soft start resistor R62 and a soft start capacitor C16;

one end of the soft start capacitor C16 is connected with a power output end and one end of a soft start capacitor C16, and the other end of the soft start capacitor C16 is grounded;

the soft start module is used for transmitting the power output signal output by the power output end to the supplied power equipment in a delayed manner, so that the pulse width is increased due to the fact that the output voltage is not established during the power-on period, and the subsequent misoperation of the overload protection circuit is avoided.

The other end of the soft-start resistor R62 in this embodiment is connected to the ref pin of the powered device, after power-on is started, the other end ref1 of the soft-start resistor R62 starts to charge the capacitor C16, and the charging threshold is set according to the parameter of the powered device; the time of soft start is adjusted through resistance R62, and the technical scheme of adopting this embodiment can effectively control the amplitude of power output signal during power-on to keep at reasonable within range, solves the problem that leads to power overload protection circuit maloperation because of power output signal increases fast in the short time, adopts conventional circuit structure effectively to promote overload protection circuit's life to be favorable to saving the cost.

Based on other embodiments, in consideration that a reverse anomaly may occur in a soft start circuit, an element or a circuit structure having a function of increasing a circuit load or realizing an anomaly protection function may be adopted, and fig. 13 shows a schematic circuit structure diagram of a soft start module of an overload protection circuit of a dc power supply according to a twelfth embodiment of the present application, and it can be known with reference to fig. 13: the soft start module of this embodiment further includes: a fourth diode D2 and a fifth diode D3 connected between the power supply output terminal and the soft start capacitor C16;

the anode of the fourth diode D2 is connected with the power output end, and the cathode of the fourth diode D2 is connected with one end of the soft start capacitor C16 and the anode of the fifth diode D3;

the cathode of the fifth diode D3 is connected to the other end of the soft-start resistor R62.

Utilize the fourth diode D2 of being connected with the power output end and the fifth diode D3 of being connected with the soft start resistance other end to protect the circuit in this embodiment, avoid soft start circuit reverse anomaly to appear, effectively guaranteed soft start circuit's reliability to promote this application power overload protection circuit's accuracy nature, control cost to a certain extent simultaneously.

According to other embodiments, the overload protection circuit of a dc power supply provided by the present application may apply one or more of the other embodiments to protect power of the dc power supply, fig. 14 is a schematic circuit structure diagram of an overload protection circuit of a dc power supply according to a fourteenth embodiment of the present application, and referring to fig. 14, it can be seen that, preferably, the overload protection circuit of the dc power supply in this embodiment applies a complete technical scheme of the foregoing embodiment, and utilizes a conventional circuit structure to effectively perform high-precision protection on the power of the dc power supply, so as to not only solve the defect that a single-parameter technical scheme in the prior art is prone to frequent actions, but also ensure the reliability of the overload protection of the dc power supply.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims (10)

1. An overload protection circuit for a dc power supply, comprising: the device comprises a protection detection module, a protection delay module and a protection control module; wherein,

the input end of the protection detection module is connected with the power output end, and the output end of the protection detection module is connected with the protection delay module and used for outputting a protection starting signal or a protection releasing signal to the protection delay module according to a power output signal of the current power output end;

the two ends of the protection delay module are respectively connected with the output end of the protection detection module and the control end of the protection control module and used for transmitting the received protection starting signal or protection releasing signal to the control end of the protection control module in a delayed manner;

and two ends of the protection control module are respectively connected to the low level and the power output end and are used for being switched on or switched off under the control of the protection starting signal or the protection releasing signal so as to start or release the protection.

2. The overload protection circuit of claim 1, further comprising: the filtering module is connected between the power output end and the protection detection module;

the filtering module is used for filtering the power output signal and transmitting the filtered power output signal to the protection detection module;

the filtering module includes: a filter resistor and a filter capacitor;

one end of the filter resistor is connected with the output end of the power supply, and the other end of the filter resistor is connected with the input end of the protection detection module;

one end of the filter capacitor is connected with the other end of the filter resistor, and the other end of the filter capacitor is grounded.

3. The overload protection circuit of claim 1, wherein the protection detection module comprises: a first comparator and a first signal providing module;

the first signal providing module is used for providing a first predetermined signal;

the positive input end of the first comparator is connected to the power output end, the negative input end of the first comparator is connected to the first signal providing module, and the first signal providing module is used for outputting a protection starting signal when the power output signal value is larger than or equal to the first preset signal value and outputting a protection releasing signal when the power output signal value is smaller than the first preset signal value;

the first signal providing module includes: a first resistor and a second resistor;

one end of the first resistor is connected with a high level, and the other end of the first resistor is connected with the negative input end of the first comparator and one end of the second resistor;

the other end of the second resistor is grounded.

4. The overload protection circuit of claim 1, wherein the protection delay module comprises: the circuit comprises a first delay resistor, a delay capacitor, a first diode and a second delay resistor;

one end of the first delay resistor is connected with the output end of the protection detection module, and the other end of the first delay resistor is connected with the control end of the protection control module and one end of the delay capacitor;

the other end of the delay capacitor is grounded;

one end of the second delay resistor is connected with the other end of the first delay resistor, and the other end of the second delay resistor is connected with one end of the delay capacitor;

the anode of the first diode is connected with one end of the delay capacitor, and the cathode of the first diode is connected with the other end of the first delay resistor.

5. The overload protection circuit of claim 4, wherein the protection delay module further comprises: the second comparator, the third delay resistor, the second diode and the second signal providing module are positioned between the first delay resistor and the protection control module;

the second signal providing module is used for providing a second predetermined signal;

the positive input end of the second comparator is connected with the other end of the first delay resistor, the negative input end of the second comparator is connected with the second signal providing module, and the output end of the second comparator is connected with the control end of the protection control module;

the anode of the second diode is connected with the output end of the second comparator, and the cathode of the second diode is connected with one end of the third delay resistor;

the other end of the third delay resistor is connected with the other end of the first delay resistor.

6. The overload protection circuit of claim 5, wherein the second signal providing module comprises:

a third resistor and a fourth resistor;

one end of the third resistor is connected with a high level, and the other end of the third resistor is connected with the negative input end of the second comparator and one end of the fourth resistor;

the other end of the fourth resistor is grounded.

7. The overload protection circuit of claim 1, wherein the protection control module comprises: the control end of the protection control module is a base electrode of the triode, and two ends of the protection control module are an emitting electrode and a collecting electrode of the triode;

and the emitter of the triode is connected to the low level, and the collector of the triode is connected to the power output end.

8. The overload protection circuit of claim 7, wherein the protection control module further comprises: a fifth resistor, a sixth resistor and a third diode;

one end of the fifth resistor is connected with the output end of the protection delay module, and the other end of the fifth resistor is connected with the base electrode of the triode and one end of the sixth resistor;

the other end of the sixth resistor is connected with an emitting electrode of the triode;

the anode of the third diode is connected with the power output end, and the cathode of the third diode is connected with the collector of the triode.

9. The overload protection circuit of claim 1, further comprising: the soft start module is connected between the power output end and the power supply device;

and the soft start module is used for transmitting the power output signal output by the power output end to the supplied power equipment in a delayed manner.

10. The overload protection circuit of claim 9, wherein the soft start module comprises: the soft start circuit comprises a soft start resistor, a soft start capacitor, a fourth diode and a fifth diode;

one end of the soft start capacitor is connected with the power output end and one end of the soft start capacitor, and the other end of the soft start capacitor is grounded;

the other end of the soft starting resistor is connected to the powered device;

the anode of the fourth diode is connected with the power output end, and the cathode of the fourth diode is connected with one end of the soft start capacitor and the anode of the fifth diode;

and the cathode of the fifth diode is connected with the other end of the soft start resistor.