CN204668906U - Load over-current protection circuit, the exploratory current foldback circuit of electric power acquisition equipment - Google Patents
Load over-current protection circuit, the exploratory current foldback circuit of electric power acquisition equipment Download PDFInfo
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- CN204668906U CN204668906U CN201520161632.6U CN201520161632U CN204668906U CN 204668906 U CN204668906 U CN 204668906U CN 201520161632 U CN201520161632 U CN 201520161632U CN 204668906 U CN204668906 U CN 204668906U
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Abstract
The utility model embodiment devises load over-current protection circuit, for the mistake/undercurrent control to the load of described electric power acquisition device external, it is arranged between a load power source end and several earth terminals, comprise: the voltage sample portion arranging near earth terminal, for gathering the DC current signal flowing through between described earth terminal and being converted to the first voltage signal; Connect the multiplication of voltage converter section in described voltage sample portion, receive this first voltage signal and be converted to the second voltage signal output; Comparator, by normal phase input end receive described the second voltage signal and by its with input described comparator inverting input tertiary voltage signal compared with output switch control signal; And MOS switch, the path that carrys out conducting according to exported switch controlling signal or turn off external loading. Correspondingly, another embodiment of the utility model designs a kind of current foldback circuit of electric power acquisition equipment.
Description
Technical field
The embodiment of the present invention is about control technique in power system, in more specific words it, the load overcurrent overload that is aimed at electric power acquisition equipment (for example ammeter) design is carried out the current foldback circuit effectively suppressing.
Background technology
In the general technology of association area of the present invention, over-current and-load protection need to be carried out to the load end of electric power acquisition equipment. Conventionally, adopt ceramic PTC (positive temperature coefficient) thermistor or high molecular PTC (positive temperature coefficient) thermistor on the one hand, realize overcurrent protection. Defect mainly contains 3 points: 1) protection resume speed is slow, exceedes the degree difference of limit value, generally even within more than several minutes, just can will move in the several seconds according to electric current. Vibration, cannot realize protection even repeatedly. Resume speed is slow, when external loading recovers normal, because the caloric requirement of internal electronic device slowly dissipates, needs even longer time several tens minutes time, cannot at once recover normal in the airtight series products such as electric energy meter; 2) owing to being that temperature sensor is subject to ambient temperature effect greatly, when circumstance of temperature difference is large, the current limit difference of protecting can reach 100%, and accurate overcurrent protection cannot be realized; (for example: being set in overcurrent limit value in the environment of 70 DEG C is 1A electric current; overcurrent limit value at-40 DEG C can reach 2A electric current) 3) the overcurrent protection prerequisite of the method is that a large amount of power need to be consumed; according in the situation of overcurrent; cause the fuel factor of device itself; cause device self-resistance to increase, this device is connected in series in circuit, finally causes output current to reduce; after reaching certain thermal balance, ensure that the constant of power output. Like this, the power output of overload is converted to heat completely, and not only cause the inner pyrotoxin that produces of electric energy meter, temperature raises, and reduces electric energy meter reliability, also results in the waste of energy. Even in high temperature environments, the overheated of electric energy meter is caused to burn.
On the other hand, adopt electronic device, cause the increase of inside of electronic component resistance according to heating, thus restriction output current, realize overcurrent protection. Method is: if load short circuits, and the power dissipation that power supply exports, on electronic device, is converted to heat, finally reaches thermal balance, thus makes power supply export the power that is limited to certain value. Defect mainly contains 2 points: 1) if load abnormal do not get rid of, electronic circuit will be made to be in overload for a long time, and overload power all at the high pyrotoxin of the inner generation of electric energy meter, causes ammeter internal temperature to raise, reduce electric energy meter reliability, also results in the waste of energy. Even in high temperature environments, the overheated of electric energy meter is caused to burn; 2) resume speed is slow, when load abnormal is cancelled, because the caloric requirement of internal electronic device slowly dissipates, needs even longer time several tens minutes time, cannot at once recover normal in the airtight series products such as electric energy meter.
Summary of the invention
In order to address the aforementioned drawbacks, the special load over-current protection circuit that major design is a kind of is applied to power collection systems.
In one aspect, the present invention first technical scheme is to utilize the collection of direct current (DC) current signal flowing through between carrying ground end as judging signal source, judge that according to comparator the size fiducial value between the voltage that this signal source converts to and comparative voltage source controls the supply access to external loading, in general example, the one or more MOS switching tubes of way selection of gauge tap, path to be powered closes to have no progeny and by the adjusting means of circuit self, signal source is reduced to lower than behind described comparative voltage source, can again restore electricity.
On the other hand, the present invention second technical scheme is the electric power acquisition equipment based on this realization, and such as ammeter, collector or negative control terminal equipment etc. are realized the power supply of equipment to external loading, the DC electric current of for example 12V simultaneously.
At another aspect; the present invention the 3rd technical scheme is designed the current foldback circuit that possesses exploratory feature on aforementioned base; " exploratory " represents this circuit by repeatedly attempting the mode of MOS switching tube described in conducting, accurately to reach the effect that suppresses load overcurrent or fault control. Even if it is unsuccessful once to attempt conducting, voltage ratio that can signalization source adjusts the size of comparative voltage, and this signal source is slowly discharged, and periodically to suppress the appearance of overcurrent or short-circuit conditions, unnecessary electric current is released by earth terminal.
Technical scheme 1: load over-current protection circuit, for the mistake/undercurrent control to the load of described electric power acquisition device external, it is arranged between a load power source end and several earth terminals, comprise: the voltage sample portion arranging near earth terminal, for gathering the DC current signal flowing through between described earth terminal and being converted to the first voltage signal; Connect the multiplication of voltage converter section in described voltage sample portion, receive this first voltage signal and be converted to the second voltage signal output; Comparator, by normal phase input end receive described the second voltage signal and by it compared with tertiary voltage signal with input return difference comparator inverting input with output switch control signal; And MOS switch, the path that carrys out conducting according to exported switch controlling signal or turn off external loading.
Technical scheme 2: electric power acquisition equipment, the load power source end of DC electric current is carried in its inner installing to its external loading; And described load over-current protection circuit.
In one embodiment, described external loading is integrated circuit or complete module with the functional pairing of this electric power acquisition equipment (for example ammeter), can, from the communication board of ammeter dismounting, infrared control module etc., also can be for example the handheld device that operation maintenance personnel is checked meter.
Technical scheme 3: the exploratory load over-current protection circuit of electric power acquisition device external load, be arranged in electric power acquisition equipment, whether recover from over-current state after inside or external loading overcurrent certain hour for periodically detecting described external loading, comprise: DC current path, be connected between load power source end and load, and be provided with several earth terminals; And exploration voltage detection department, be connected in described DC current path, detect that for basis the DC current signal flowing through between described several earth terminals repeatedly controls the break-make of described DC current path, wherein said exploration voltage detection department comprises: the voltage sample portion arranging near earth terminal, for gathering the DC current signal flowing through between described earth terminal and being converted to the first voltage signal; Connect the multiplication of voltage converter section in described voltage sample portion, receive this first voltage signal and be converted to the second voltage signal output; Return difference comparator, by normal phase input end receive described the second voltage signal and by its with input described return difference comparator inverting input tertiary voltage signal compared with output switch control signal; MOS switch, the path that carrys out conducting according to exported switch controlling signal or turn off described external loading; And connect the voltage transformation into itself portion of described return difference comparator inverting input, carry out the height of the second voltage signal described in periodic variation for the break-make according to MOS switch, to change the on off operating mode of described MOS switch.
Based on this, the technology of the present invention is remarkably productive: 1, resume speed is fast, after outside Abnormality remove can be realized, accomplishes self-recoverage within 0.5 second. Protection speed is fast, can accomplish that 10 milliseconds of internal cutting off abnormal loads are powered; 2, the accurate control of overcurrent protection can be accomplished, and with return difference, avoid circuit repeatedly to vibrate, not be subject to the impact of environment temperature simultaneously; 3, in addition in the short-circuit state, only have 1%-10% can set that the overload power consumption of ratio is dissipated on electronic device, other power does not export, and avoids electric energy meter inside under short-circuit conditions and causes strong pyrotoxin, greatly strengthen the reliability of electric energy meter internal components, and reduce the waste of the energy.
Accompanying drawing explanation
Fig. 1 is the local circuit schematic diagram of load over-current protection circuit of the present invention;
Fig. 2 is the comparison diagram of load current curve map of the present invention and routine techniques thermistor load current curve map.
Detailed description of the invention
With reference to Fig. 1 with detailed description technical essential of the present invention and advantage.
Embodiment 1: in FIG; a load over-current protection circuit is for the mistake/undercurrent control to external loading ELD; it is arranged at (for example, 2 earth terminal GND_A and GND_B shown in Fig. 1) between a load power source end VCC and several earth terminals, and wherein main circuit will comprise:
The R8 of voltage sample portion arranging near earth terminal GND_A, or the similar impedance device substituting, for the electric current I flowing through from GND_A to GND_B is converted to voltage, be namely converted to the first voltage signal V4 in the embodiment shown in fig. 1;
Connect the multiplication of voltage converter section of the described voltage sample R8 of portion, comprise operational amplifier U11, the described voltage sample R8 of portion accesses described operational amplifier U11 normal phase input end INA+, inputs this first voltage signal V4. Its inverting input INA-connects respectively divider resistance R1 and R2, described divider resistance ground connection GND_A end. Produce branch pressure voltage V5 at inverting input INA-place according to divider resistance R1, and utilize this branch pressure voltage V5 that the first voltage signal V4 is converted to the second voltage signal V6 output. Can learn from Fig. 1 embodiment, operational amplifier U11 and divider resistance R2 form a mlultiplying circuit, namely meet
V6＝β·V5， (1)；
Wherein according to the embodiment of Fig. 1, β=(R1+R2)/R1, namely meets
In a preferred example, set V4=V5, multiplication factor is decided by R1;
Comparator, is received described the second voltage signal V6 by its normal phase input end INB+, or voltage signal V1. In an alternative embodiment, a voltage modulation circuit is set between described multiplication of voltage converter section and comparator, and it comprises cutoff device, for example diode D1 and with it the resistance R3 of series connection. Thus make:
The inverting input INB-of resistance R3 concatenation operation amplifier U12. Described comparator preferably comprises operational amplifier U12, the divider resistance R4 of concatenation operation amplifier U12 normal phase input end INB+ respectively, R5, R10, by its with input described comparator U12 inverting input INB-tertiary voltage signal V2 compared with output switch control signal V3; And
MOS switch 20, the path that carrys out conducting according to exported switch controlling signal or turn off described external loading.
Further, described return difference comparator is configured to: when described the second voltage signal is higher than tertiary voltage signal, and output low level switch controlling signal, to turn off MOS switch 20, cuts off the power supply of described load power source end to external loading; And after described the second voltage signal is brought down below tertiary voltage signal, output-feedback stabilization switch controlling signal with the MOS switch 20 described in conducting, the power supply of load power source end to external loading described in conducting, namely voltage V2 meets relational expression:
As improvement, with relational expression (3) accordingly, the reversed-phase output of described comparator connects again voltage transformation into itself portion, comprises resistance R9 and in parallel electric capacity C1 with it, is configured to the second voltage signal V1 described in periodic transformation.
Embodiment 2: the electric power acquisition equipment of realizing based on embodiment 1, the load power source end of DC electric current is carried in its inner installing to its external loading; And the load over-current protection circuit described in embodiment 1.
In one embodiment, described external loading 10 comprises the integrated circuit of the functional pairing with described electric power acquisition equipment.
Embodiment 3: equally with reference to Fig. 1, design a kind of exploratory load over-current protection circuit similar to Example 1ly, be arranged in an electric power acquisition equipment, whether recover from over-current state after inside or external loading 10 overcurrent certain hour for periodically detecting described external loading 10, circuit comprises: DC current path, be connected between load power source end and load, and be provided with several earth terminals; And exploration voltage detection department, is connected in described DC current path, and detect that for basis the DC current signal flowing through between described several earth terminals repeatedly controls the break-make of described DC current path, wherein said exploration voltage detection department comprises:
The R8 of voltage sample portion arranging near earth terminal GND_A, for gathering the DC current signal flowing through between described earth terminal GND_A and GND_B and being converted to the first voltage signal V4;
Connect the multiplication of voltage converter section of the described voltage sample R8 of portion, receive this first voltage signal V4 and be converted to the second voltage signal V6 output; Wherein as the improvement on embodiment 1 basis, comparator U12 selects return difference comparator, by its normal phase input end INB+ receive described the second voltage signal V1 and by its compared with inputting the tertiary voltage signal V2 of described return difference comparator inverting input INB-with output switch control signal V3;
MOS switch 10, the path that carrys out conducting according to exported switch controlling signal V3 or turn off described external loading 20; And
Connect the voltage transformation into itself portion of described return difference comparator U12 inverting input INB-, comprise bleeder resistor R9 and the in parallel electric capacity C1 that releases with it, it carrys out the height of the second voltage signal V1 described in periodic variation according to the break-make of MOS switch 10, to change the on off operating mode of described MOS switch 10.
Further, described return difference comparator U12 is configured to: when described the second voltage signal V1 is higher than tertiary voltage signal V2, output low level switch controlling signal (for example 0V), to turn off MOS switch 10, cuts off the power supply of described load power source end to external loading; And after described the second voltage signal V1 is brought down below tertiary voltage signal V2, output-feedback stabilization switch controlling signal (for example controlling VCC=V3) with the MOS switch 10 described in conducting, the power supply of load power source end to external loading 20 described in conducting.
Improve as it, described voltage transformation into itself portion comprises: the holding capacitor C1 of connection inverting input, and with it and the resistance R9 connecing, after described MOS switch OFF, inverting input is discharged. Wherein, described resistance R9 is set to high resistance measurement, makes it inverting input INB-slowly discharge.
With reference to Fig. 1, the exploratory load overcurrent suppressing method based on this embodiment 3 circuit realiration includes step:
101, turned back to from GND_A point the electric current that GND_B is ordered by the R8 of voltage sample portion sampling, produce the first voltage V4, and be converted to the second voltage signal V4 by multiplication of voltage converter section.
Wherein, a direct current DC out-put supply between+VCC and GND, can be regarded as. Turned back to from GND_A point the electric current that GND_B is ordered by resistance R8 sampling, the current value that flows through sampling resistor R8 is converted to the first magnitude of voltage V4, by operational amplifier U11, certain multiplication factor β is set, and be converted into the second higher voltage signal V6, voltage V1 is directly proportional to the second voltage V6. When output current transships, voltage signal V1 voltage signal is higher than by third voltage value V2 relatively, when output current is within limited range, and V1 voltage signal is lower than by comparing voltage value V2;
102, when the output voltage signal V1 of operational amplifier U11 is higher than during by comparing voltage value V2, the output signal V3 of return difference comparator U12 is low level, control the metal-oxide-semiconductor 10 that is series at load 20 loop and be in off state, thus cut off the return path of electric current I from GND_A to GND_B, protect power supply VCC and be in not output state;
103, when metal-oxide-semiconductor 10 is in off state by control, the voltage on voltage sample portion (resistance R8) is reduced to 0V, and at this moment the second voltage V6 exports as 0V. Simultaneously, inverting input INB-due to operational amplifier U12 there is a holding capacitor C1, C1 is discharged by resistance R9, and the resistance that resistance R9 is set is comparatively large, determines the second voltage signal V1 and slowly declines, because operational amplifier U12 is return difference comparator, when voltage signal V1 slowly declines, continue for some time, reach lower than after voltage signal V2, the output switch control voltage signal V3 that just triggers operational amplifier U12 becomes high level, again controls metal-oxide-semiconductor U2 and is in opening state;
If 104 again sound out and open metal-oxide-semiconductor 10, detect that load is still transshipped, make to turn back to from GND_A point the electric current that GND_B orders and still exceed limit value, the process of repetitive cycling step 102 and step 103;
If the electric current in 105 loads is within limit value scope, MOS switching tube 10 returns to normally state, and load power source end VCC recovers normal and exports. When electric circuit inspection is to power source loads 20 abnormal overload, by design special parameter, circuit will cut off the power supply to load 20 automatically, after lasting time to the circuit that turns off A second is opened automatically, whether extremely, sound out load 20, the time of unlatching is A/10 second or A/100 second. If load 20 is still abnormal, will again circulates and cut off load supplying A second, cycle detection. If load is normal, recover normal power supply.
Industrial applicibility comparative analysis
With reference to Fig. 2; made in load 20 under abnormality by this method embodiment; the energy of its loss only has 1/10 or 1/100 (ratio is adjustable) of peak power output; load heating temperature rise is less; generally can be controlled within 10 DEG C, and the power dissipating on original protection circuit is more than the maximum power dissipation of circuit configuration. Therefore, circuit of the present invention can be described as low-power consumption exploration type current foldback circuit. Meanwhile, the cycle of souning out due to circuit is A second, ensure that after load abnormal overload removes, and within A second, normal power supply can be recovered.
The present invention is by setting corresponding circuit parameter; by the intermittent method of opening protection metal-oxide-semiconductor of souning out of hardware circuit; ensure under the overload of DC output power; averaged overload power output is much smaller than the situation of existing current foldback circuit; meanwhile, the characteristic of rapid recovery normal power supply is also there is.
Claims (6)
1. load over-current protection circuit, is characterized in that it is arranged between a load power source end and several earth terminals, comprising:
The voltage sample portion arranging near earth terminal, for gathering the direct current DC current signal flowing through between described earth terminal and being converted to the first voltage signal;
Connect the multiplication of voltage converter section in described voltage sample portion, receive this first voltage signal and be converted to the second voltage signal output;
Comparator, by normal phase input end receive described the second voltage signal and by its with input described comparator inverting input tertiary voltage signal compared with output switch control signal; And
MOS switch, the path that carrys out conducting according to exported switch controlling signal or turn off external loading.
2. load over-current protection circuit according to claim 1, is characterized in that: the inverting input of described comparator connects again voltage transformation into itself portion, is configured to the second voltage signal described in periodic transformation.
3. electric power acquisition equipment, is characterized in that: the load power source end of DC electric current is carried in inner installing to its external loading; And load over-current protection circuit according to claim 1.
4. electric power acquisition equipment according to claim 3, is characterized in that: described external loading comprises the integrated circuit of the functional pairing with described electric power acquisition equipment.
5. the exploratory current foldback circuit of electric power acquisition device external load, is characterized in that comprising: DC current path, is connected between load power source end and load, and is provided with several earth terminals; And exploration voltage detection department, is connected in described DC current path, and detect that for basis the DC current signal flowing through between described several earth terminals repeatedly controls the break-make of described DC current path, wherein said exploration voltage detection department comprises:
The voltage sample portion arranging near earth terminal, for gathering the DC current signal flowing through between described earth terminal and being converted to the first voltage signal;
Connect the multiplication of voltage converter section in described voltage sample portion, receive this first voltage signal and be converted to the second voltage signal output;
Return difference comparator, by normal phase input end receive described the second voltage signal and by its with input described return difference comparator normal phase input end tertiary voltage signal compared with output switch control signal;
MOS switch, the path that carrys out conducting according to exported switch controlling signal or turn off described external loading; And
Connect the voltage transformation into itself portion of described return difference comparator inverting input, carry out the height of the second voltage signal described in periodic variation for the break-make according to MOS switch, to change the on off operating mode of described MOS switch.
6. exploratory current foldback circuit according to claim 5, is characterized in that: described voltage transformation into itself portion comprises: the holding capacitor C1 of connection inverting input, and with it and the resistance R9 connecing, after described MOS switch OFF, inverting input is discharged.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201520161632.6U CN204668906U (en) | 2015-03-20 | 2015-03-20 | Load over-current protection circuit, the exploratory current foldback circuit of electric power acquisition equipment |
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| CN201520161632.6U CN204668906U (en) | 2015-03-20 | 2015-03-20 | Load over-current protection circuit, the exploratory current foldback circuit of electric power acquisition equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104810785A (en) * | 2015-03-20 | 2015-07-29 | 华立仪表集团股份有限公司 | Load over-current protection circuit, electric power acquisition equipment and tentative over-current protection circuit used for electric power acquisition equipment |
| CN110024250A (en) * | 2016-11-25 | 2019-07-16 | 哈曼贝克自动系统股份有限公司 | For managing the circuit and method of inrush current |
-
2015
- 2015-03-20 CN CN201520161632.6U patent/CN204668906U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104810785A (en) * | 2015-03-20 | 2015-07-29 | 华立仪表集团股份有限公司 | Load over-current protection circuit, electric power acquisition equipment and tentative over-current protection circuit used for electric power acquisition equipment |
| CN104810785B (en) * | 2015-03-20 | 2018-07-17 | 华立科技股份有限公司 | Electric power acquisition device external loads exploratory current foldback circuit |
| CN110024250A (en) * | 2016-11-25 | 2019-07-16 | 哈曼贝克自动系统股份有限公司 | For managing the circuit and method of inrush current |
| US11146059B2 (en) | 2016-11-25 | 2021-10-12 | Harman Becker Automotive Systems Gmbh | Circuit and method for managing an inrush current |
| CN110024250B (en) * | 2016-11-25 | 2021-11-23 | 哈曼贝克自动系统股份有限公司 | Circuit and method for managing inrush current |
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Address after: HOLLEY Technology Park No. 181 310023 Hangzhou city Zhejiang District of Yuhang province Wuchang Avenue Patentee after: HOLLEY METERING LIMITED Address before: HOLLEY Technology Park No. 181 310023 Hangzhou city Zhejiang District of Yuhang province Wuchang Avenue Patentee before: Holley Metering Ltd. |