阅读说明：本技术 一种多级软硬件交叉互控可调过流保护系统及方法 (Multistage software and hardware cross mutual control adjustable overcurrent protection system and method ) 是由 曾雪刚 王正宁 钟其水 曾彦 孙艳 于 2021-07-19 设计创作，主要内容包括：本发明公开了一种多级软硬件交叉互控可调过流保护系统及方法,该过流包括系统包括软件模块、硬件模块及信号锁存模块,本发明提供的系统通过软件识别保护加硬件实时保护的模式,针对有大脉冲需要的负载,机能正确识别和通过负载打脉冲时所需的大电流,又能在真正产生过流的时候准确及时保护；且通过信号锁止模块能够实现对目标电路输出进行锁定,达到有效地的过流保护。(The invention discloses a multistage software and hardware cross mutual control adjustable overcurrent protection system and a method, wherein the overcurrent protection system comprises a software module, a hardware module and a signal latch module, and the system provided by the invention can correctly identify and pulse the required large current through the load by aiming at the load with large pulse requirement through a mode of software identification protection and hardware real-time protection, and can also accurately protect in time when overcurrent is really generated; and the output of the target circuit can be locked through the signal locking module, so that effective overcurrent protection is achieved.)

1. The utility model provides an adjustable overcurrent protection system of multistage software and hardware cross mutual control which characterized in that, this system includes:

a software module storing a computer program that executes a process of: performing analog-to-digital conversion on the input target current, comparing the conversion result with a set current threshold value, and if the target current is greater than the current threshold value and smaller than the normal pulse current, delaying for a certain time; continuously comparing the target current with the normal pulse current in the delay period, and if the target current is increased to the normal pulse current in the delay period, judging that the target current is the normal pulse current at the moment and having no action; otherwise, outputting an interrupt signal to the target circuit to cut off the output of the target circuit, thereby realizing overcurrent protection; if the target current is larger than the current threshold value and is larger than the normal pulse current, no action is performed;

the hardware module comprises an overcurrent protection unit and a short-circuit protection unit and is used for overcurrent protection and short-circuit protection;

the signal latch module outputs a latch signal to the target circuit to cut off the output of the target circuit when the target circuit has overcurrent;

when the system works, the software module and the hardware module are both in a power-on state, and when the input target current is larger than a current threshold value set by the software module and smaller than a normal pulse current, the software module acts to execute a computer program stored in the software module; when the input target current is larger than the current threshold value set by the software module and is larger than the normal pulse current, or the input target current is larger than the current threshold value of the short-circuit protection unit or the overcurrent protection unit, the hardware module operates;

the current threshold value set by the software module, the current threshold value of the over-current protection unit and the current threshold value of the short-circuit protection unit are different.

2. The multi-stage software and hardware cross-over inter-control adjustable overcurrent protection system of claim 1, wherein: the short-circuit protection unit and/or the over-current protection unit comprise a comparator used for comparing the target current with the current threshold value and a counter used for starting counting when the target current is larger than the current threshold value and outputting the target current to the signal latch module when the target current overflows.

3. The multi-stage software and hardware cross-over inter-control adjustable overcurrent protection system of claim 2, wherein: and the voltage digital-to-analog converter is used for providing a reference value for the comparator as a current threshold value.

4. The multi-stage software and hardware cross-over inter-control adjustable overcurrent protection system of claim 3, wherein: the comparator, the counter and/or the voltage analog-to-digital converter are programmable integrated circuits and can be electrically connected with a terminal to realize the regulation and control of the current threshold value.

5. The multi-stage software and hardware cross-over inter-control adjustable overcurrent protection system of claim 1, wherein: the signal latch module comprises a first NOR gate, a second NOR gate, a first NOT gate, a second NOT gate, an AND gate and a D-Q trigger; the outputs of the short-circuit protection unit and the overcurrent protection unit are respectively used as two inputs of a first NOR gate and an input of the D-Q trigger, the output of the first NOR gate is used as one input of a second NOR gate, a second input of the second NOR gate loads a control signal, and the output of the second NOR gate is used as a clock signal of the D-Q trigger; the output of the first nor gate is also used as the input of the first not gate, and the output of the first not gate is used as one path of input of the and gate; and the output of the D-Q trigger is used as the input of the second NOT gate, the output of the second NOT gate is used as the other path of input of the AND gate, the output of the AND gate is used as a latch signal to be loaded on a target circuit to cut off the output, and the cut-off output state is locked, so that the overcurrent protection is realized.

6. The multi-stage software and hardware cross-over inter-control adjustable overcurrent protection system of claim 5, wherein: the signal latch module further comprises a control register, the control register is used for receiving an external signal and outputting the external signal to be used as the other path of input of the second NOR gate and the input of the D-Q trigger respectively, when overcurrent occurs, the signal latch module outputs a signal to enable a target circuit to be cut off and output and locked, when an external signal is input into the control register, the output of the control register enables the output of the D-Q trigger to be changed, and the output of the AND gate enables the target circuit to be recovered, so that unlocking is achieved.

7. The multi-stage software and hardware cross-over inter-control adjustable overcurrent protection system according to claim 5 or 6, wherein: the signal latch module further comprises a state register, wherein the outputs of the short-circuit protection unit and the overcurrent protection unit are input into the state register, and the state register latches the current overcurrent state.

8. The multi-stage software and hardware cross-over inter-control adjustable overcurrent protection system of claim 1, wherein: the device also comprises a clock module for providing a clock signal, and a signal amplification module for amplifying the target current, wherein the output of the signal amplification module is input into the software module and the hardware module; the signal amplification module comprises a programmable gain amplifier and a digital-to-analog converter for providing a direct current bias signal for the programmable gain amplifier.

9. The overcurrent protection method of the multistage software and hardware cross-mutual control adjustable overcurrent protection system based on any one of claims 1 to 8, characterized by comprising the following steps: starting an overcurrent protection system, collecting current in a target circuit on line in real time to form target current, and comparing the target current with a current threshold value set in a software module and current threshold values of a short-circuit protection unit and an overcurrent protection unit in a hardware module; if the target current is larger than the current threshold value set by the software module and smaller than the normal pulse current, the software module acts to execute the computer program stored in the software module; if the input target current is larger than the current threshold value set by the software module and is larger than the normal pulse current, or the input target current is larger than the current threshold value of the short-circuit protection unit or the overcurrent protection unit, the hardware module acts; the current threshold value set by the software module, the current threshold value of the over-current protection unit and the current threshold value of the short-circuit protection unit are different.

10. The overcurrent protection method of the multistage software and hardware cross-mutual control adjustable overcurrent protection system according to claim 9, characterized in that: when the input target current is larger than a current threshold value set by a software module and is larger than a normal current pulse, or the input target current is larger than the current threshold value of the short-circuit protection unit or the over-current protection unit, the output of the over-current protection unit or the short-circuit protection unit exists after a certain time delay; setting a current threshold, namely setting multi-stage current threshold values used for overcurrent judgment, wherein the current threshold values of each stage are different;

setting a normal pulse current;

setting time delay corresponding to the current threshold value series;

collecting a target circuit current and recording the target circuit current as a target current; if the target current is smaller than all current threshold values in the set multi-stage current threshold values, the target current is judged to be normal current; if the target current is greater than one or more of the multi-stage current threshold values, comparing the target current with a set normal pulse current, if the target current is less than the normal pulse current, delaying the time length corresponding to the current threshold value that the target current is greater than, continuously collecting the target current during the delay time and comparing the target current with the set normal pulse current, if the target current is increased to the set normal pulse current during the delay time, judging that the target current is the normal pulse current at the moment, not starting the over-current protection, continuously collecting and comparing the target current, if the target current is greater than the set current threshold value and the current threshold value is equal to or greater than the normal pulse current, delaying the time length corresponding to the current threshold value that the target current is greater than at the moment, if the set delay time is reached, starting the over-current protection if the target current is continuously greater than the current threshold value, otherwise, the overcurrent protection is not started; if the target current cannot be increased to the set normal pulse current after the set time delay is reached, judging that the target current is overcurrent current, and starting overcurrent protection; if the target current is greater than one or more of the set multi-stage current threshold values and the current threshold value is equal to or greater than the normal pulse current, delaying the time corresponding to the current threshold value for which the target current is greater than the current threshold value at the moment, if the set time delay is reached, starting overcurrent protection if the target current is continuously greater than the current threshold value, otherwise, not starting overcurrent protection;

if the target current is larger than one or more of the set multi-stage current threshold values, and the current threshold value is equal to or larger than the normal pulse current, the current threshold value larger than the target current at the moment is delayed for the shortest time.

Technical Field

The invention relates to a multistage software and hardware cross mutual control adjustable overcurrent protection system and a method.

Background

At present, the main method of overcurrent protection is threshold detection. When the current value reaches the threshold value, the protection circuit acts to cut off the current loop. However, the conventional method cannot solve the problem that a special load has an instantaneous large current requirement when working normally, which is called as "pulse beating", and at this time, the peak pulse value of the current is far larger than the protection current threshold value, the conventional protection method easily causes system misoperation, generates false protection or needs to set the threshold value to be too large, and the power supply and the load are damaged because the protection is not performed when the protection is really needed.

Disclosure of Invention

In order to overcome the defects of the traditional threshold detection method, the invention aims to provide the multistage software and hardware cross mutual control adjustable overcurrent protection system which can identify normal pulse current and effectively perform overcurrent protection.

The purpose of the invention is realized by the following technical scheme, the multistage software and hardware cross mutual control adjustable overcurrent protection system comprises:

a software module storing a computer program that executes a process of: performing analog-to-digital conversion on the input target current, comparing the conversion result with a set current threshold value, and if the target current is greater than the current threshold value and smaller than the normal pulse current, delaying for a certain time; continuously comparing the target current with the normal pulse current in the delay period, and if the target current is increased to the normal pulse current in the delay period, judging that the target current is the normal pulse current at the moment and having no action; otherwise, outputting an interrupt signal to the target circuit to cut off the output of the target circuit, thereby realizing overcurrent protection; if the target current is larger than the current threshold value and is larger than the normal pulse current, no action is performed;

the hardware module comprises an overcurrent protection unit and a short-circuit protection unit and is used for overcurrent protection and short-circuit protection;

the signal latching module is used for outputting a latching signal to a target circuit according to the output of the software module and/or the hardware module to cut off the output of the target circuit, so that the overcurrent protection of the target circuit is realized;

when the system works, the software module and the hardware module are both in a power-on state, and when the input target current is larger than a current threshold value set by the software module and smaller than a normal pulse current, the software module acts to execute a computer program stored in the software module; when the input target current is larger than the current threshold value set by the software module and is larger than the normal pulse current, or the input target current is larger than the current threshold value of the short-circuit protection unit or the overcurrent protection unit, the hardware module operates;

the current threshold value set by the software module, the current threshold value of the over-current protection unit and the current threshold value of the short-circuit protection unit are different.

Further, in some embodiments, the short-circuit protection unit and/or the over-current protection unit includes a comparator for comparing a target current with a current threshold value, and a counter for starting counting when the target current is greater than the current threshold value, and outputting the counter to the signal latch module when the target current overflows.

Further, in some embodiments, the current threshold value is a reference value of the comparator.

Further, in some embodiments, the comparator, the counter and/or the voltage analog-to-digital converter are programmable integrated circuits, and may be electrically connected to a terminal to implement regulation of the current threshold. The programmable integrated circuit is adopted, the current threshold value and the timing duration can be regulated and controlled according to the use condition, namely, the protection condition can be flexibly adjusted according to the load condition, and the programmable integrated circuit has the advantages of strong adaptability and strong expansibility.

Further, in some embodiments, the signal latch module includes a first nor gate, a second nor gate, a first not gate, a second not gate, an and gate, and a D-Q flip-flop; the outputs of the short-circuit protection unit and the overcurrent protection unit are respectively used as two inputs of a first NOR gate and an input of the D-Q trigger, the output of the first NOR gate is used as one input of a second NOR gate, a second input of the second NOR gate loads a control signal, and the output of the second NOR gate is used as a clock signal of the D-Q trigger; the output of the first nor gate is also used as the input of the first not gate, and the output of the first not gate is used as one path of input of the and gate; and the output of the D-Q trigger is used as the input of the second NOT gate, the output of the second NOT gate is used as the other path of input of the AND gate, the output of the AND gate is used as a latch signal to be loaded on a target circuit to cut off the output, and the cut-off output state is locked, so that the overcurrent protection is realized. The output of the module can be used for controlling the output locking of a target circuit and is continuous when an overcurrent state occurs, and the overcurrent protection effect is further improved.

Further, in some embodiments, the signal latch module further includes a control register, the control register is configured to receive an external signal and output the external signal as another input of the second nor gate and an input of the D-Q flip-flop, after an overcurrent occurs, the signal latch module outputs a signal to cut off an output of the target circuit and lock the target circuit, when an external signal is input to the control register, the output of the control register changes the output of the D-Q flip-flop, and the output of the and gate restores the target circuit to achieve unlocking.

Further, in some real-time modes, the signal latch module further includes a status register, outputs of the short-circuit protection unit and the overcurrent protection unit are input into the status register, and the status register latches a current overcurrent state; the locking of the overcurrent state is realized, and the locking device can be used by subsequent related equipment and workers to judge whether the overcurrent state of the target circuit is short-circuit overcurrent or current overcurrent.

Further, in some embodiments, the system further comprises a clock module for providing a clock signal.

Further, in some embodiments, the system further comprises a signal amplification module for amplifying the target current, wherein an output of the signal amplification module is input to the software module and the hardware module.

Further, in some real-time modes, the signal amplification module includes a programmable gain amplifier and a digital-to-analog converter for providing a dc bias signal to the programmable gain amplifier.

Another object of the present invention herein is to provide an overcurrent protection method based on the overcurrent protection system provided by the present invention, the method is as follows: starting an overcurrent protection system, collecting current in a target circuit on line in real time to form target current, and comparing the target current with a current threshold value set in a software module and current threshold values of a short-circuit protection unit and an overcurrent protection unit in a hardware module; if the target current is larger than the current threshold value set by the software module and smaller than the normal pulse current, the software module acts to execute the computer program stored in the software module; if the input target current is larger than the current threshold value set by the software module and is larger than the normal pulse current, or the input target current is larger than the current threshold value of the short-circuit protection unit or the overcurrent protection unit, the hardware module acts; the current threshold value set by the software module, the current threshold value of the over-current protection unit and the current threshold value of the short-circuit protection unit are different.

Further, when the input target current is greater than a current threshold value set by the software module and is greater than a normal current pulse, or the input target current is greater than a current threshold value of the short-circuit protection unit or the over-current protection unit, and a certain time is delayed, the over-current protection unit or the short-circuit protection unit outputs the current.

A third aspect of the present invention herein provides a multi-stage overcurrent protection method, including:

setting a current threshold, namely setting multi-stage current threshold values used for overcurrent judgment, wherein the current threshold values of each stage are different;

setting a normal pulse current;

setting time delay corresponding to the current threshold value series;

collecting a target circuit current and recording the target circuit current as a target current; if the target current is smaller than all current threshold values in the set multi-stage current threshold values, the target current is judged to be normal current; if the target current is greater than one or more of the multi-stage current threshold values, comparing the target current with a set normal pulse current, if the target current is less than the normal pulse current, delaying the time length corresponding to the current threshold value that the target current is greater than, continuously collecting the target current during the delay time and comparing the target current with the set normal pulse current, if the target current is increased to the set normal pulse current during the delay time, judging that the target current is the normal pulse current at the moment, not starting the over-current protection, continuously collecting and comparing the target current, if the target current is greater than the set current threshold value and the current threshold value is equal to or greater than the normal pulse current, delaying the time length corresponding to the current threshold value that the target current is greater than at the moment, if the set delay time is reached, starting the over-current protection if the target current is continuously greater than the current threshold value, otherwise, the overcurrent protection is not started; if the target current cannot be increased to the set normal pulse current after the set time delay is reached, judging that the target current is overcurrent current, and starting overcurrent protection; if the target current is larger than one or more of the set multi-stage current threshold values and the current threshold value is equal to or larger than the normal pulse current, delaying the time corresponding to the current threshold value larger than the target current at the moment, if the set time delay is reached, starting the overcurrent protection if the target current is continuously larger than the current threshold value, otherwise, not starting the overcurrent protection.

Further, if the target current is greater than one or more of the set multi-level current threshold values, and the current threshold value is equal to or greater than the normal pulse current, the current threshold value at which the target current is greater than is delayed for the shortest time.

The system provided by the invention can correctly identify and pass the heavy current required by the pulse beating of the load and can accurately protect in time when overcurrent is really generated aiming at the circuit required by the large pulse current through the mode of software identification protection and hardware real-time protection; and the output of the target circuit can be locked through the signal locking module, so that effective overcurrent protection is achieved.

The invention has the beneficial effects that: compared with the existing threshold detection, the invention can not only correctly identify and pulse the required heavy current through the load, but also accurately and timely protect the power supply and the load when the overcurrent is really generated by aiming at the load with the requirement of 'pulse big pulse' through the mode of software identification protection and hardware real-time protection. Meanwhile, the value of the overcurrent protection threshold and the timing time can be adjusted through the programmable integrated circuit, and different types of loads can be effectively compatible. The method has the advantages of strong adaptability and strong expansibility: namely, the protection condition can be flexibly adjusted according to the load condition. The protection window of at least 2 levels can be expanded under the condition of sufficient digital and analog resources, and more accurate overcurrent waveform control is provided.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1 is a schematic block diagram of an overcurrent protection system provided by the present invention;

FIG. 2 is a schematic diagram of an overcurrent protection system provided by the present invention;

fig. 3 is a waveform diagram of actual control.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art.

In the process that the power supply supplies power to the load, some loads have instantaneous heavy current requirements at the moment of starting or during normal operation. As shown in fig. 3, the PULSEs PULSE1 and PULSE2 in the figure are normal PULSE currents required by the load operation, and the current values thereof generally exceed the current protection threshold, and the current overcurrent protection easily determines the instantaneous large current required by the load as an overcurrent, so as to cause the false protection, and cannot meet the target circuit with the instantaneous large current requirement. The invention provides a multistage software and hardware cross mutual control adjustable overcurrent protection system which can be used for overcurrent protection of any target circuit, particularly provides overcurrent and short circuit protection functions for a power supply and a load, can identify normal pulse current of the load (the pulse current value is greater than a primary overcurrent protection threshold value), and can be applied to the field of new energy power supplies.

Fig. 1 and fig. 2 show an exemplary schematic block diagram and a schematic diagram of an overcurrent protection system provided by the present invention, where the overcurrent protection system includes a signal amplification module, a software module ADC, a hardware module, and a signal latch module, and each functional module is specifically as follows.

And the signal amplification module is used for amplifying the acquired target current of the target circuit, and the amplified target current is respectively input into the software module and the hardware module. The signal amplification module may employ any of various amplification circuits, and an exemplary circuit structure employed herein includes a programmable gain amplifier PGA responsible for amplifying the target current signal to an appropriate value and a digital-to-analog converter VDAC _ L1 providing a dc bias signal to the programmable gain amplifier PGA via a digital-to-analog converter VDAC _ L1.

A software module ADC storing a computer program that executes a process of: performing analog-to-digital conversion on the input target current, comparing the conversion result with a set current threshold value, and if the target current is greater than the current threshold value and smaller than the normal pulse current, delaying for a certain time; continuously comparing the target current with the normal pulse current in the delay period, and if the target current is increased to the normal pulse current in the delay period, judging that the target current is the normal pulse current at the moment and having no action; otherwise, outputting an interrupt signal to the target circuit to cut off the output of the target circuit, thereby realizing overcurrent protection; if the target current is larger than the current threshold value and larger than the normal pulse current, no action is taken.

The hardware module comprises a short-circuit protection unit for judging whether a target circuit has a short circuit or not and an overcurrent protection unit for judging whether the target circuit has an overcurrent or not; the number of the over-current protection units and the number of the short-circuit protection units are set according to the requirements of the over-current protection system, and at least one over-current protection unit is arranged. The over-current protection unit and the short-circuit protection unit may be any over-current protection unit or short-circuit protection unit, and an exemplary circuit structure adopted herein is as follows: the overcurrent protection unit and the short-circuit protection unit are respectively provided with a comparator COMP, a COUNTER COUNTER and an analog-to-digital converter VDAC, the output end of the comparator COMP is connected with the enabling end of the COUNTER COUNTER, and the interrupt output end of the COUNTER COUNTER is connected with the signal latch module; the non-inverting input end of the comparator COMP is connected with the output end of the programmable gain amplifier PGA, and the analog-to-digital converter VDAC is connected with the inverting input end of the comparator COMP.

Specifically, referring to fig. 2, the overcurrent protection unit includes a comparator COMPL2, a counter 2, and an analog-to-digital converter VDACL 2; the short-circuit protection unit comprises a comparator COMPL3, a counter count 3 and an analog-to-digital converter VDACL 3. The non-inverting input ends of the comparator COMPL2 and the comparator COMPL3 are respectively connected with the output end of the programmable gain amplifier PGA, and the output ends of the analog-to-digital converter VDACL2 and the analog-to-digital converter VDACL3 are respectively connected with the inverting input ends of the comparator COMPL2 and the comparator COMPL 3; the output terminals of the comparator COMPL2 and the comparator COMPL3 are respectively connected with the RESET terminals of the counter COUNTERL2 and the counter COUNTERL 3.

Here, in the exemplary circuit structures of the over-current protection unit and the short-circuit protection unit provided herein, the output terminals of the comparator COMPL2 and the comparator COMPL3 may be directly connected to the input terminals of the counter 2 and the counter 3, respectively, or may be connected through a not gate, respectively.

The analog-to-digital converter VDACL2 and the analog-to-digital converter VDACL3 respectively determine current threshold values of the overcurrent protection unit and the short-circuit protection unit; the compare-count periods of counter 2 and counter 3 set the time delays for over-current protection and short-circuit protection, respectively.

And the signal latch module outputs a latch signal to the target circuit to cut off the output of the target circuit when the target circuit has overcurrent, so that the overcurrent protection of the target circuit is realized. The exemplary circuit structure of the signal latch module provided herein is shown in fig. 2 and includes a first nor gate, a second nor gate, a first not gate, a second not gate, an and gate, a D-Q flip-flop, a Control register Control _ Reg _ PRTMOD _1, and a Status register Status _ Reg _ OCTYPE _ 1. The outputs of the short-circuit protection unit and the over-current protection unit are respectively used as two inputs of a first NOR gate and the input of a D-Q trigger, the output of the first NOR gate is used as one input of a second NOR gate, the second input of the second NOR gate is loaded with a control signal, and the output of the second NOR gate is used as a clock signal of the D-Q trigger; the output of the first NOR gate is also used as the input of the first NOR gate, and the output of the first NOR gate is used as one path of input of the AND gate; the output of the D-Q trigger is used as the input of a second NOT gate, the output of the second NOT gate is used as the other path of input of an AND gate, the output of the AND gate is used as a control signal and loaded in a target circuit to cut off the output of the target circuit, the purpose of cutting off the output of the target circuit and locking the target circuit is continuously achieved, and effective overcurrent protection is achieved.

The control register is used for receiving an external signal and outputting the external signal as the other path of input of the second NOR gate and the input of the D-Q trigger respectively, and when overcurrent occurs, the signal latch module outputs a signal to enable the target circuit to cut off the output and continuously cut off the state to realize locking; after the output of the target circuit is cut off and latched, when an external signal is input into the control register, the output of the control register enables the output of the D-Q trigger to change, and the output of the AND gate enables the target circuit to recover, so that unlocking is achieved.

The output of the short-circuit protection unit and the output of the over-current protection unit are input into a state register, and the state register latches the current over-current state. As shown in the exemplary circuit configuration of fig. 2, the outputs of counter 2 and counter 3 are respectively input to a status register, the status register is different according to the different outputs of the inputs to represent different overcurrent conditions (short-circuit overcurrent or overcurrent), and the output of the status register can be read and used by an external device to obtain the overcurrent condition.

When the system works, the software module and the hardware module are both in a power-on state, and when the input target current is larger than a current threshold value set by the software module and smaller than a normal pulse current, the software module acts to execute a computer program stored in the software module; when the input target current is larger than the current threshold value set by the software module and is larger than the normal pulse current, or the input target current is larger than the current threshold value of the short-circuit protection unit or the overcurrent protection unit, the hardware module operates; the current threshold value set by the software module, the current threshold value of the over-current protection unit and the current threshold value of the short-circuit protection unit are different.

In the exemplary circuit structure provided herein, the comparator, the counter, and the digital-to-analog converter may be any one, for example, a programmable integrated circuit may be used, and the comparator, the counter, and the digital-to-analog converter may be in communication connection with a terminal installed with programming software, and the overcurrent protection threshold value and the timing duration may be set by operating installed editing software. By adopting the programmable gain amplifier PGA, the overcurrent protection unit and the short-circuit protection unit, the overcurrent protection threshold value and the timing time can be adjusted, and different types of loads can be effectively compatible. The method has the advantages of strong adaptability and strong expansibility: namely, the protection condition can be flexibly adjusted according to the load condition.

The overcurrent protection method of the multistage software and hardware cross mutual control adjustable overcurrent protection system comprises the following steps: starting an overcurrent protection system, collecting current in a target circuit on line in real time to form target current, and comparing the target current with a current threshold value set in a software module and current threshold values of a short-circuit protection unit and an overcurrent protection unit in a hardware module; if the target current is larger than the current threshold value set by the software module and smaller than the normal pulse current, the software module acts to execute the computer program stored in the software module; if the input target current is larger than the current threshold value set by the software module and is larger than the normal pulse current, or the input target current is larger than the current threshold value of the short-circuit protection unit or the overcurrent protection unit, the hardware module acts; the current threshold value set by the software module, the current threshold value of the over-current protection unit and the current threshold value of the short-circuit protection unit are different.

When the input target current is larger than the current threshold value set by the software module and is larger than the normal current pulse, or the input target current is larger than the current threshold value of the short-circuit protection unit or the over-current protection unit, the output of the over-current protection unit or the short-circuit protection unit exists after a certain time delay.

Another multi-stage overcurrent protection method comprises the following steps:

setting a current threshold, namely setting multi-stage current threshold values used for overcurrent judgment, wherein the current threshold values of each stage are different;

setting a normal pulse current;

setting time delay corresponding to the current threshold value series;

collecting a target circuit current and recording the target circuit current as a target current; if the target current is smaller than all current threshold values in the set multi-stage current threshold values, the target current is judged to be normal current; if the target current is greater than one or more of the multi-stage current threshold values, comparing the target current with a set normal pulse current, if the target current is less than the normal pulse current, delaying the time length corresponding to the current threshold value that the target current is greater than, continuously collecting the target current during the delay time and comparing the target current with the set normal pulse current, if the target current is increased to the set normal pulse current during the delay time, judging that the target current is the normal pulse current at the moment, not starting the over-current protection, continuously collecting and comparing the target current, if the target current is greater than the set current threshold value and the current threshold value is equal to or greater than the normal pulse current, delaying the time length corresponding to the current threshold value that the target current is greater than at the moment, if the set delay time is reached, starting the over-current protection if the target current is continuously greater than the current threshold value, otherwise, the overcurrent protection is not started; if the target current cannot be increased to the set normal pulse current after the set time delay is reached, judging that the target current is overcurrent current, and starting overcurrent protection; if the target current is larger than one or more of the set multi-stage current threshold values and the current threshold value is equal to or larger than the normal pulse current, delaying the time corresponding to the current threshold value larger than the target current at the moment, if the set time delay is reached, starting the overcurrent protection if the target current is continuously larger than the current threshold value, otherwise, not starting the overcurrent protection.

If the target current is larger than one or more of the set multi-stage current threshold values, and the current threshold value is equal to or larger than the normal pulse current, the current threshold value larger than the target current at the moment is delayed for the shortest time.

The technical scheme provided by the invention can realize at least three-level overcurrent protection responses, namely, a software module level and a hardware module which comprises two levels of overcurrent protection and short-circuit protection, certainly not only three levels recorded in the software module, but also multiple levels can be designed according to requirements, for example, the hardware module is designed with multiple levels of overcurrent protection and short-circuit protection, and different current threshold values and delay time are configured. The current threshold value and the time delay of each time are different, for example, the current threshold value of the short-circuit protection can be the largest, and the shortest external clock period is realized.

The overcurrent protection system provided herein also includes a clock module that provides a clock signal to the system, where the clock module employs a frequency divider FreqDiv2, which may employ a frequency divider 1/2; other dividers may of course be chosen as the case may be.

In combination with the exemplary circuit structure of each functional module provided herein, all modules in the overcurrent protection system communicate with the outside through an API interface, and the signal latch module outputs a system interrupt and a latch signal, where the system interrupt includes overcurrent state information for use by an external device and for knowing the overcurrent state of a target circuit; the latch signal is used for loading the target circuit and cutting off the output of the target circuit. The non-inverting input end of the programmable gain amplifier PGA is connected with a target circuit current sampling signal, a voltage signal generated by the target circuit current flowing through the sensor is sent to the software monitoring module and the hardware module, and when the software monitoring module detects that the current is larger than a preset primary software protection threshold, T1 is delayed (T1 is the time between the load changing from the normal working current to the pulse current value), and the detection is carried out again. If the hardware overcurrent or short circuit alarm is triggered at the moment, the detection is stopped, and the system interrupt triggered by the hardware calls a relevant processing process. If the current is smaller than the preset pulse current value, the load is judged to be abnormal, and if the overcurrent occurs, a primary overcurrent alarm flag bit is set to output a latch signal for protection. If the current is larger than the preset pulse current value, the normal pulse current required by the load is judged, the detection is stopped, and the controller for latching the signal is controlled by hardware with overcurrent protection and short-circuit protection. When the level of any comparator is turned over, the RESET bit corresponding to the COUNTER is cleared, the COUNTER starts to time, when the COUNTER overflows, the INTERRUPT output bit INTERRUPT of the COUNTER is turned over from 0 to 1, the signal latching logic unit is triggered, the protection level and type are locked, and the protection latching signal and the INTERRUPT request signal are output. And meanwhile, the corresponding position of the over-current state register is set, and the protection state is locked. The system needs to respond to the interrupt and then releases the protection state through the API interface of the calling module. If the level of the comparator is turned over again before the COUNTER overflows, the current is reduced to be below the protection threshold, the RESET position 1 of the COUNTER, and the corresponding counting module of the COUNTER is automatically RESET; the entire system waits for the next trigger signal.

Due to the existence of the input capacitor, the load has the impact current as shown in fig. 3 when being electrified and started, and different loads have different capacitances. By using the technical scheme, after the protection thresholds and the time delays of all levels are configured, the starting pulse in the dotted line range can normally pass, and both the load and the power supply can normally work; the start pulse beyond the range of the dotted line triggers corresponding protection, and the power supply cuts off the output and gives an alarm to indicate that the load is abnormal.

The PULSEs PULSE1 and PULSE2 shown in fig. 3 are normal PULSE currents required by the load to work, and the current values exceed the protection threshold and the duration exceeds the delay time of the primary protection threshold. The over-current protection system and the over-current protection method can correctly identify the pulse, can not generate error protection action, and can not accidentally cut off the power supply to influence the normal work of the load.

In combination with the exemplary circuit structures of the functional modules provided herein, the system clock, the signal amplification factor, the dc bias voltage, the overcurrent threshold value, the delay time and the like in the overcurrent protection system and method provided herein may be arbitrarily defined according to the usage, and in order to better explain the technical solution herein, the following exemplary settings are provided herein for illustration.

The system clock is set to be 8MHz, and after passing through the frequency divider, the counting clock is set to be 4MHz through the frequency divider; the amplification factor of the PGA is set to be 4 times, and the direct current bias voltage of the PGA is set to be 2528 mv; the turnover level of the hardware overcurrent protection is set to 3584mv, and the delay of the hardware overcurrent protection is set to 4000 counting cycles; the turning level of the hardware short-circuit protection is set to be 3728mv, and the time delay of the hardware short-circuit protection is set to be 4 counting cycles; the software overcurrent protection detection threshold is set to 12000mA, and the software overcurrent protection detection threshold delay is set to 10 ms; the software pulse detection threshold was set at 350000 mA.

According to the setting, the threshold of the software module protection is 12A, and the delay is 10 ms. And if the current is detected to exceed 12A for 10ms and not reach the pulse current (normal pulse current) threshold (350A), triggering the software module to realize software overcurrent protection. If the current exceeds 350A within 10ms, the current is identified as normal pulse current (large current required by the target circuit), and the software gives protection authority to the hardware. The overcurrent protection threshold in the hardware module is 528A, and the delay is 1 ms. And if the pulse current value exceeds 528A and lasts for more than 1ms, triggering hardware overcurrent protection. The short-circuit protection threshold is 600A, and the time delay is 1 us. If the pulse current value exceeds 600A and lasts for more than 1us, short-circuit protection is triggered. Pulses within this range can be recognized and passed normally without triggering protective action.

Based on the above settings, the actual test results are: a pulse of 400A duration of 5 seconds can pass normally without a protective action trigger. 15A lasts for 12ms, and software overcurrent protection is triggered. 550A lasts for 1ms, and hardware overcurrent protection is triggered. 650A lasts 1us, triggering short-circuit protection.

By adopting the scheme, compared with the existing threshold detection, the method can identify the heavy current pulse of the normal load and effectively perform overcurrent protection on the power supply and the load. The mode of software identification protection and hardware real-time protection is adopted, so that the adaptability of the power supply system to the load is greatly improved, particularly for the load with the requirement of pulse amplification, the high current required by pulse amplification through the load can be accurately identified, and the power supply and the load can be accurately and timely protected when overcurrent is really generated. Meanwhile, the value of the overcurrent protection threshold and the timing time are adjusted through the programmable gain amplifier PGA and the overcurrent protection unit, and different types of loads can be effectively compatible. The method has the advantages of strong adaptability and strong expansibility: namely, the protection condition can be flexibly adjusted according to the load condition. The protection window of at least 2 levels can be expanded under the condition of sufficient digital and analog resources, and more accurate overcurrent waveform control is provided.

The above embodiments are only for illustrating the technical solutions of the present invention and are not limited, and modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention are included in the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.