CN110350485B - Current protection module, system and method - Google Patents

Current protection module, system and method Download PDF

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Publication number
CN110350485B
CN110350485B CN201910629467.5A CN201910629467A CN110350485B CN 110350485 B CN110350485 B CN 110350485B CN 201910629467 A CN201910629467 A CN 201910629467A CN 110350485 B CN110350485 B CN 110350485B
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current protection
current
triode
resistor
capacitor
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CN110350485A (en
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石明杰
刘启武
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Sichuan Hongmei Intelligent Technology Co Ltd
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Sichuan Hongmei Intelligent Technology Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Protection Of Static Devices (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention provides a current protection module, a system and a method, wherein the current protection module comprises: the current protection circuit comprises a main chip, a triode connected with the main chip, a current protection threshold value design unit and a differential comparator chip; a plurality of groups of differential comparators which correspond to each power switch circuit in the external multi-path PFC module one by one are arranged in the differential comparator chip; the first input end of the differential comparator is connected with the corresponding power switch circuit, the second input end of the differential comparator is connected with the current protection threshold value design unit, and the output end of the differential comparator is connected with the triode; the differential comparator chip samples the current sampling signal of each power switch circuit, and when any corresponding numerical value exceeds a current protection threshold value, the triode is controlled to be conducted; when the triode is conducted, the main chip determines that the current of the multiple PFC modules is abnormal and executes current protection processing. Because the current conditions of a plurality of circuits can be monitored simultaneously through one current protection module, a plurality of current protection modules are not required to be arranged, and the product cost is lower.

Description

Current protection module, system and method
Technical Field
The present invention relates to the field of electronic technologies, and in particular, to a current protection module, a system, and a method.
Background
With the technical progress, a multi-path PFC (Power Factor Correction) module is slowly applied to a high-Power air conditioner variable frequency driver. The multi-PFC module typically includes at least two-way power switching circuits. For example, it is common to have a multi-path interleaved active PFC module including two or three power switching circuits, each of which operates sequentially at a phase of 90 ° or 120 °.
At present, a current protection module connected with a single-circuit PFC module can be designed aiming at the single-circuit PFC module, and once the single circuit has abnormal current, the current protection module can execute corresponding protection processing, so that the single-circuit PFC module can work stably and reliably. Based on similar realization principles, aiming at a plurality of paths of PFC modules, a plurality of current protection modules respectively connected with each circuit can be designed so as to correspondingly monitor the current condition of each circuit.
Because a plurality of current protection modules are needed, the product cost is high.
Disclosure of Invention
The invention provides a current protection module, a system and a method, which have lower product cost.
In a first aspect, the present invention provides a current protection module, comprising:
the current protection circuit comprises a main chip, a triode, a current protection threshold value design unit and a differential comparator chip with a plurality of groups of differential comparators;
wherein the differential comparator comprises a first input terminal, a second input terminal and an output terminal;
at least two groups of first differential comparators in the multiple groups of differential comparators correspond to at least two power switch circuits in an external multi-path PFC module one to one;
for any one of the first differential comparators, a first input end of the first differential comparator is connected with the corresponding power switch circuit, a second input end of the first differential comparator is connected with the current protection threshold value design unit, and an output end of the first differential comparator is connected with the triode;
the triode is connected with the main chip;
the differential comparator chip is used for sampling a current sampling signal of each power switch circuit; when the value corresponding to any one current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit, controlling the triode to be conducted;
and the main chip is used for determining that the current of the multi-path PFC module is abnormal and executing current protection processing when the triode is conducted.
Further, the current protection threshold value designing unit includes: the circuit comprises a first capacitor, a second capacitor, a third capacitor, a first resistor and a second resistor;
a first end of the first capacitor is connected to a VCC (voltage supply) pin of the differential comparator chip, and a second end of the first capacitor is grounded;
the first end of the second capacitor is connected with the VCC pin, and the second end of the second capacitor is grounded;
the first end of the third capacitor is respectively connected with the second input end of each first differential comparator, and the second end of the third capacitor is grounded;
the first end of the first resistor is connected with the first end of the third capacitor, and the second end of the first resistor is grounded;
the first end of the second resistor is connected with the VCC pin, and the second end of the second resistor is connected with the first end of the third capacitor;
correspondingly, the current protection threshold value accords with a formula I;
the first formula comprises: v0＝[R1/(R1+R2)]×U
Wherein, V0And R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, and U is the voltage value at the VCC pin.
Further, the current protection module further includes: at least two third resistors and at least two fourth capacitors which are in one-to-one correspondence with the at least two groups of first differential comparators;
the first end of any one third resistor is connected with the first input end of the corresponding first differential comparator, and the second end of the third resistor is connected with the power switch circuit corresponding to the corresponding first differential comparator;
and the first end of any one fourth capacitor is connected with the first input end of the corresponding first differential comparator, and the second end of the fourth capacitor is grounded.
Further, the current protection module further includes: a fifth capacitor, a fourth resistor and a fifth resistor;
the first end of the fifth capacitor is connected with the triode, and the second end of the fifth capacitor is grounded;
the first end of the fourth resistor is connected with the first end of the fifth capacitor, and the second end of the fourth resistor is connected with the main chip;
and the first end of the fifth resistor is connected with the second end of the fourth resistor, and the second end of the fifth resistor is grounded.
Furthermore, the triode is a PNP triode;
the first input end is an In-pin, and the second input end is an In + pin;
the output end of any one of the first differential comparators is connected with the base electrode of the PNP triode;
the main chip is connected with the collector of the PNP triode;
the emitting electrode of the PNP triode is connected with external voltage;
in a corresponding manner, the first and second electrodes are,
the differential comparator chip is used for outputting a low level signal to the base electrode of the PNP triode when the value corresponding to any current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit;
the PNP triode is used for outputting a high-level signal to the main chip through a collector when a base electrode inputs a low-level signal to enable the external voltage to be conducted from an emitter electrode to the collector electrode;
and the main chip is used for determining that the current abnormality occurs in the multi-path PFC module when a high-level signal is input.
Further, the triode is an NPN triode;
the first input end is an In + pin, and the second input end is an In-pin;
the output end of any one of the first differential comparators is connected with the base electrode of the NPN triode;
the main chip is connected with an emitting electrode of the NPN triode;
the collector of the NPN triode is connected with external voltage;
in a corresponding manner, the first and second electrodes are,
the differential comparator chip is used for outputting a high-level signal to the base electrode of the NPN triode when the value corresponding to any current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit;
the NPN triode is used for outputting a high-level signal to the main chip through an emitter when a base electrode inputs a high-level signal so as to enable the external voltage to be conducted from a collector electrode to the emitter electrode;
and the main chip is used for determining that the current abnormality occurs in the multi-path PFC module when a high-level signal is input.
Further, the number of the groups of the plurality of groups of differential comparators is greater than the number of the at least two power switch circuits;
and the first input end and the second input end of other differential comparators in the multiple groups of differential comparators are connected with external voltage.
In a second aspect, the present invention provides a current protection system comprising:
the multi-path PFC module comprises at least two power switch circuits and any one of the current protection modules;
the multi-path PFC module is used for outputting the current sampling signals of the power switch circuits to the current protection module.
Further, the power switching circuit includes: an Insulated Gate Bipolar Transistor (IGBT) switching tube, a diode, and a sixth resistor;
the IGBT switching tube is characterized in that a PWM (Pulse Width Modulation) signal is input to a grid electrode of the IGBT switching tube, an emitter outputs a current sampling signal, and a collector is connected with the anode of the diode;
and the first end of the sixth resistor is connected with the emitter of the IGBT switching tube, and the second end of the sixth resistor is grounded.
In a third aspect, the present invention provides a current protection method based on any one of the current protection modules, including:
sampling current sampling signals of each power switch circuit in the multi-path PFC module by using the differential comparator chip;
when the value corresponding to any one current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit, the triode is controlled to be conducted by using the differential comparator chip;
and when the triode is conducted, the main chip is utilized to determine that the multiple PFC modules have abnormal current and execute current protection processing.
The invention provides a current protection module, a system and a method, wherein the current protection module comprises: the current protection circuit comprises a main chip, a triode connected with the main chip, a current protection threshold value design unit and a differential comparator chip; a plurality of groups of differential comparators which correspond to each power switch circuit in the external multi-path PFC module one by one are arranged in the differential comparator chip; the first input end of the differential comparator is connected with the corresponding power switch circuit, the second input end of the differential comparator is connected with the current protection threshold value design unit, and the output end of the differential comparator is connected with the triode; the differential comparator chip samples the current sampling signal of each power switch circuit, and when any corresponding numerical value exceeds a current protection threshold value, the triode is controlled to be conducted; when the triode is conducted, the main chip determines that the current of the multiple PFC modules is abnormal and executes current protection processing. Because the current conditions of a plurality of circuits can be monitored simultaneously through one current protection module, a plurality of current protection modules are not required to be arranged, and the product cost is lower.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced 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 creative efforts.
Fig. 1 is a schematic diagram of a current protection module according to an embodiment of the present invention;
fig. 2 is a schematic diagram of another current protection module according to an embodiment of the invention;
fig. 3 is a schematic diagram of another current protection module according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a power switch circuit according to an embodiment of the present invention;
fig. 5 is a flowchart of a current protection method according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the 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, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the scope of the present invention.
As shown in fig. 1, an embodiment of the present invention provides a current protection module, which may include:
the circuit comprises a main chip 101, a triode 102, a current protection threshold value design unit 103 and a differential comparator chip 104 with a plurality of groups of differential comparators 1041;
the differential comparator 1041 includes a first input terminal 10411, a second input terminal 10412, and an output terminal 10413;
at least two first differential comparators in the multiple differential comparators 1041 correspond to at least two power switch circuits in the external multi-channel PFC module one to one;
for any of the first differential comparators, the first input terminal 10411 thereof is connected to the corresponding power switch circuit, the second input terminal 10412 thereof is connected to the current protection threshold value designing unit 103, and the output terminal 10413 thereof is connected to the transistor 102;
the triode 102 is connected with the main chip 101;
the differential comparator chip 104 is configured to sample a current sampling signal of each of the power switch circuits; when a value corresponding to any one of the current sampling signals exceeds the current protection threshold value determined by the current protection threshold value design unit 103, controlling the triode 102 to be conducted;
the main chip 101 is configured to determine that a current abnormality occurs in the multiple PFC modules and execute current protection processing when the triode 102 is turned on.
An embodiment of the present invention provides a current protection module, including: the current protection circuit comprises a main chip, a triode connected with the main chip, a current protection threshold value design unit and a differential comparator chip; a plurality of groups of differential comparators which correspond to each power switch circuit in the external multi-path PFC module one by one are arranged in the differential comparator chip; the first input end of the differential comparator is connected with the corresponding power switch circuit, the second input end of the differential comparator is connected with the current protection threshold value design unit, and the output end of the differential comparator is connected with the triode; the differential comparator chip samples the current sampling signal of each power switch circuit, and when any corresponding numerical value exceeds a current protection threshold value, the triode is controlled to be conducted; when the triode is conducted, the main chip determines that the current of the multiple PFC modules is abnormal and executes current protection processing. Because the current conditions of a plurality of circuits can be monitored simultaneously through one current protection module, a plurality of current protection modules are not required to be arranged, and the product cost is lower.
In the embodiment of the invention, the current sampling signal of the power switch circuit is collected by the differential comparator. Therefore, the number of groups of the differential comparators in the differential comparator chip is not less than the number of the power switch circuits in the multi-path PFC module, so that the current sampling signal of each power switch circuit can be acquired.
After the chip samples the current sampling signals of each circuit, whether the current sampling signals are abnormal or not can be judged, if the current sampling signals are abnormal, the connected triodes can be controlled to be conducted, and current abnormal information is transferred to the triodes. When any circuit is not abnormal, the triode is not controlled to be conducted.
After the triode is conducted, the current abnormal information can be transmitted to the main chip. The main chip can determine that the current abnormality occurs in the multiple PFC modules and execute current protection processing in time. For example, the master chip may control the related circuits to stop working and report fault information.
Specifically, the differential comparator has two input ends and an output end, one input end is connected with the power switch circuit to input the current sampling signal, the other input end is connected with the current protection threshold value design unit to determine the reference of comparison, and the output end is connected with the triode. In this way, the value of the current sampling signal is compared with the reference value, and a corresponding level signal is output. Based on the above, when the value is greater than the reference value, it is determined that the current is abnormal, and thus the output level signal should turn on the transistor.
For example, when the transistor is a PNP transistor, the transistor may be turned on when a low level signal is input to the transistor and may not be turned on when a high level signal is input, based on the characteristics of the PNP transistor. For another example, when the transistor is an NPN transistor, the transistor may be turned on when a high level signal is input to the transistor and may not be turned on when a low level signal is input to the transistor based on characteristics of the NPN transistor.
The two input ends of the differential comparator are respectively a non-inverting input end and an inverting input end. When the voltage of the non-inverting input end is larger than that of the inverting input end, the output end can output a high level signal, otherwise, the output end can output a low level signal. Based on this, and based on the characteristics of the transistor, it is possible to determine which input terminal the power switch circuit is connected to.
Hereinafter, the different transistors will be described in a limited manner.
In detail, for the PNP transistor:
in an embodiment of the invention, referring to fig. 2, the transistor 102 is a PNP transistor;
the first input terminal 10411 is an In-pin, and the second input terminal 10412 is an In + pin;
the output end 10413 of any first differential comparator is connected with the base electrode of the PNP triode;
the main chip 101 is connected with a collector of the PNP triode;
the emitting electrode of the PNP triode is connected with external voltage;
in a corresponding manner, the first and second electrodes are,
the differential comparator chip 104 is configured to output a low level signal to the base of the PNP triode when a value corresponding to any one of the current sampling signals exceeds the current protection threshold determined by the current protection threshold design unit 103;
the PNP triode is configured to output a high level signal to the main chip 101 through the collector when a low level signal is input to the base to turn on the external voltage from the emitter to the collector;
the main chip 101 is configured to determine that a current abnormality occurs in the multiple PFC modules when a high level signal is input.
Specifically, the non-inverting input terminal corresponds to the In + pin, the inverting input terminal corresponds to the In-pin, and the output terminal corresponds to the Out pin.
Based on the above, when the PNP transistor is selected, the transistor can be turned on only when the current is abnormal and the chip needs to output a low level signal. When the voltage of the non-inverting input terminal is less than the voltage of the inverting input terminal, the output terminal will output a low level signal, and when the current is abnormal, the value corresponding to the current sampling signal will exceed the current protection threshold value, so the power switch circuit needs to be connected to the inverting input terminal, i.e. the first input terminal is an In-pin.
Referring to fig. 2, the differential comparator chip is D1, the main chip is D2, and the transistor is V1.
Fig. 2 shows a multi-PFC module having 3 power switch circuits and 4 differential comparators in the differential comparator chip. Thus, the 3 circuits can be respectively connected with the In pins of any 3 groups of differential comparators. Correspondingly, the current protection threshold value design unit is connected with the corresponding In + pin.
For example, referring to fig. 2, the 3 circuits are respectively connected to 4 pins, 6 pins, and 8 pins of the chip, the current protection threshold value design unit is respectively connected to 5 pins, 7 pins, and 9 pins of the chip, and the triodes are respectively connected to 1pin, 2 pins, and 14 pins of the chip. And the remaining set of differential comparators, i.e., 10pin, 11pin, 13pin of the chip, i.e., In-pin 4, In + pin 4, Out pin 4, are reserved.
Correspondingly, referring to fig. 2, the emitter of the PNP transistor is connected to the external voltage, and the collector is connected to the main chip. Therefore, when any circuit is abnormal, the chip can compare that the value of the corresponding current sampling signal exceeds the current protection threshold value, and the chip outputs low level to the base electrode, so that the PNP triode is conducted. Specifically, an external voltage connected to the emitter may be conducted from the emitter to the collector, thereby causing the collector to output a high level signal to the master chip. And the main chip receives the high-level signal and executes current protection processing.
As illustrated in fig. 2, this external voltage may be + 5V.
In detail, for the NPN transistor:
in an embodiment of the invention, referring to fig. 3, the transistor 102 is an NPN transistor;
the first input terminal 10411 is an In + pin, and the second input terminal 10412 is an In-pin;
the output end 10413 of any first differential comparator is connected with the base electrode of the NPN triode;
the main chip 101 is connected with an emitting electrode of the NPN triode;
the collector of the NPN triode is connected with external voltage;
in a corresponding manner, the first and second electrodes are,
the differential comparator chip 104 is configured to output a high-level signal to the base of the NPN triode when a value corresponding to any one of the current sampling signals exceeds the current protection threshold determined by the current protection threshold design unit 103;
the NPN transistor is configured to output a high level signal to the main chip 101 through an emitter when a base inputs a high level signal to conduct the external voltage from a collector to the emitter;
the main chip 101 is configured to determine that a current abnormality occurs in the multiple PFC modules when a high level signal is input.
Based on the above, when the NPN transistor is selected, the transistor can be turned on only when the current is abnormal and the chip needs to output a high level signal. When the voltage of the In-phase input end is greater than the voltage of the reverse-phase input end, the output end can output a high level signal, and when the current is abnormal, the value corresponding to the current sampling signal exceeds the current protection threshold value, so the power switch circuit needs to be connected with the In-phase input end, namely the first input end is an In + pin.
Referring to fig. 3, the differential comparator chip is D1, the main chip is D2, and the transistor is V1.
Fig. 3 shows a multi-PFC module having 3 power switch circuits and 4 differential comparators in the differential comparator chip. Thus, the 3 circuits can be respectively connected with the In + pins of any 3 groups of differential comparators. Correspondingly, the current protection threshold value design unit is connected with the corresponding In-pin.
For example, referring to fig. 3, the 3 circuits are respectively connected to 5 pins, 7 pins, and 9 pins of the chip, the current protection threshold value design unit is respectively connected to 4 pins, 6 pins, and 8 pins of the chip, and the triodes are respectively connected to 1pin, 2 pins, and 14 pins of the chip. And the remaining set of differential comparators, i.e., 10pin, 11pin, 13pin of the chip, i.e., In-pin 4, In + pin 4, Out pin 4, are reserved.
Correspondingly, referring to fig. 3, the collector of the NPN transistor is connected to the external voltage, and the emitter is connected to the main chip. Therefore, when any circuit is abnormal, the chip can compare that the value of the corresponding current sampling signal exceeds the current protection threshold value, and the chip outputs high level to the base electrode so as to conduct the NPN triode. Specifically, an external voltage connected to the collector may be conducted from the collector to the emitter, thereby causing the emitter to output a high-level signal to the master chip. And the main chip receives the high-level signal and executes current protection processing.
As illustrated in fig. 3, this external voltage may be + 5V.
In an embodiment of the invention, referring to fig. 2 or fig. 3, the current protection threshold value designing unit 103 includes: the circuit comprises a first capacitor, a second capacitor, a third capacitor, a first resistor and a second resistor;
a first end of the first capacitor is connected to the VCC pin of the differential comparator chip 104, and a second end of the first capacitor is grounded;
the first end of the second capacitor is connected with the VCC pin, and the second end of the second capacitor is grounded;
the first end of the third capacitor is connected to the second input terminal 10412 of each first differential comparator, and the second end is grounded;
the first end of the first resistor is connected with the first end of the third capacitor, and the second end of the first resistor is grounded;
the first end of the second resistor is connected with the VCC pin, and the second end of the second resistor is connected with the first end of the third capacitor;
correspondingly, the current protection threshold value accords with a formula I;
the first formula comprises: v0＝[R1/(R1+R2)]×U
Wherein, V0And R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, and U is the voltage value at the VCC pin.
In detail, referring to fig. 2 or fig. 3, the first capacitor is CE1, the second capacitor is C2, the third capacitor is C3, the first resistor is R1, and the second resistor is R2.
In the embodiment of the present invention, referring to fig. 2 or fig. 3, CE1 may be an electrolytic capacitor, C1 may be a ceramic capacitor, and the two capacitors are combined together to form a filter circuit, which is mainly used to filter an external voltage, i.e., an interference signal at +5V, so as to ensure normal operation of the circuit and prevent false alarm of fault information. Therefore, the accuracy of current protection can be improved.
In detail, the current protection threshold value design unit is mainly used for designing a current protection threshold value, specifically, the current protection threshold value is designed by being connected with 3 In + pins (5pin, 7pin and 9pin) of the chip, and a current protection threshold value calculation formula is the formula one. Thus, the magnitude of the current protection threshold can be adjusted as required by adjusting the resistances of the resistors R1 and R2. As mentioned above, this current protection threshold is the reference value for the numerical comparison.
Referring to FIG. 2 or FIG. 3, an external voltage is connected to the VCC pin of the chip, the external voltage is +5V, so V0＝5×R1/(R1+R2)。
In an embodiment of the present invention, referring to fig. 2 or fig. 3, the current protection module further includes: at least two third resistors and at least two fourth capacitors which are in one-to-one correspondence with the at least two groups of first differential comparators;
a first end of any one of the third resistors is connected to the first input end 10411 of the corresponding first differential comparator, and a second end of the any one of the third resistors is connected to the power switch circuit corresponding to the corresponding first differential comparator;
the first end of any one of the fourth capacitors is connected to the first input terminal 10411 of the corresponding first differential comparator, and the second end is grounded.
In detail, referring to fig. 2 or fig. 3, there are 3 power switch circuits in the multi-path PFC module, so 3 third resistors and 3 fourth capacitors are required. The 3 third resistors are respectively R3, R4 and R5, and the 3 fourth capacitors are respectively C4, C5 and C6.
As shown in fig. 2 or fig. 3, R3 and C4 form an RC filter capacitor, R4 and C5 form an RC filter capacitor, and R5 and C6 form an RC filter capacitor, and these 3 RC filter capacitors are respectively used to filter out interference signals in 3 circuits to avoid false triggering.
In an embodiment of the present invention, referring to fig. 2 or fig. 3, the current protection module further includes: a fifth capacitor, a fourth resistor and a fifth resistor;
the first end of the fifth capacitor is connected to the triode 102, and the second end is grounded;
the first end of the fourth resistor is connected with the first end of the fifth capacitor, and the second end of the fourth resistor is connected with the main chip 101;
and the first end of the fifth resistor is connected with the second end of the fourth resistor, and the second end of the fifth resistor is grounded.
In detail, referring to fig. 2 or fig. 3, the fifth capacitor is C7, the fourth resistor is R6, and the fifth resistor is R7.
In detail, R7 is a pull-down resistor that pulls the corresponding pin of the main chip low when no current protection is occurring. When the circuit current is normal, the triode is not conducted and a high level signal cannot be output to the main chip, and in the process, the R7 pulls down the corresponding pin of the main chip, so that the main chip inputs a low level signal. Corresponding to the above, since a low level signal is input instead of a high level signal, the main chip may consider that no abnormality occurs in the circuit current.
In detail, R6 and C7 form an RC filter capacitor for filtering out interference signals to avoid false triggering.
In an embodiment of the present invention, please refer to fig. 2 or fig. 3, the number of sets of the multiple sets of differential comparators is greater than the number of the at least two power switch circuits;
the first input terminal 10411 and the second input terminal 10412 of the other differential comparators in the plurality of sets of differential comparators are connected to the external voltage.
When the number of sets of the plurality of sets of differential comparators is greater than the number of the power switch circuits, there may be redundant other differential comparators. For example, referring to fig. 2 or fig. 3, the number of sets of the plurality of sets of differential comparators is 4, and the number of the power switch circuits is 3, so that there is no more differential comparator.
In order to ensure the operation stability, the two input ends of any redundant differential comparator can be connected with external voltage. Namely, the voltage values of the non-inverting input terminal and the inverting input terminal are consistent and mutually offset. Referring to fig. 2 or fig. 3, the set of differential comparators including In + pin 4, In-pin 4, and Out pin 4 is redundant, so that both In + pin 4 and In-pin 4 can be connected to a +5V voltage.
In an embodiment of the present invention, referring to fig. 2 or fig. 3, the capacitor and the resistor may be selected as patch capacitors. Of course, in other embodiments of the present invention, the capacitor and the resistor may be inserted.
In summary, the embodiments of the present invention provide a novel current protection module, which can simultaneously monitor the current conditions of each power switch circuit in a multi-path PFC module, and notify a main chip to perform current protection processing when the current abnormality is monitored. And then, specifically analyzing which path or paths of power switch circuits are abnormal according to requirements. Therefore, the novel current protection module provided by the embodiment of the invention can solve the current protection function of three-path or two-path staggered active PFC on the variable-frequency air conditioner driver, so that the variable-frequency air conditioner driver can stably and reliably work.
As shown in fig. 1, an embodiment of the present invention provides a current protection system, including: the multi-path PFC module comprises at least two power switch circuits and any one of the current protection modules;
the multi-path PFC module is used for outputting the current sampling signals of the power switch circuits to the current protection module.
The current protection module used in the embodiment of the invention only needs one differential comparator chip, one triode, one main chip and one current protection threshold value design unit, can monitor the current conditions of a plurality of power switch circuits simultaneously through one current protection circuit, and has the advantages of high integration level, simple connection and greatly reduced product cost.
In an embodiment of the present invention, referring to fig. 4, the power switch circuit includes: the IGBT switching tube, the diode and the sixth resistor;
the grid electrode of the IGBT switching tube inputs a PWM signal, the emitting electrode outputs a current sampling signal, and the collecting electrode is connected with the anode of the diode;
and the first end of the sixth resistor is connected with the emitter of the IGBT switching tube, and the second end of the sixth resistor is grounded.
In detail, referring to fig. 4, the IGBT switch is V2, the diode is VD1, and the sixth resistor is R8.
In the application scenario of a high-power air conditioner variable frequency driver, an IGBT is usually selected. Referring to fig. 4, the IGBT inputs the PWM signal and outputs the current sampling signal. Of course, based on the existence of the sixth resistor, the current sampling signal can be converted into a voltage signal through the action of the resistor in the multi-path PFC module, thereby facilitating the comparison between the voltage value and the reference voltage value, i.e., the current protection threshold value.
In an embodiment of the invention, the anode of the diode may be connected to an inductor, and the cathode of the diode may be connected to a large capacitor.
As shown in fig. 5, an embodiment of the present invention provides a current protection method based on any one of the current protection modules, which may include the following steps:
step 501: and sampling current sampling signals of each power switch circuit in the multi-path PFC module by using the differential comparator chip.
Step 502: and when the value corresponding to any one current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit, the triode is controlled to be conducted by utilizing the differential comparator chip.
Step 503: and when the triode is conducted, the main chip is utilized to determine that the multiple PFC modules have abnormal current and execute current protection processing.
The information interaction, execution process and other contents between the units in the method are based on the same concept as the embodiment of the apparatus of the present invention, and specific contents can be referred to the description in the embodiment of the apparatus of the present invention, and are not described herein again.
In summary, the embodiments of the present invention have at least the following advantages:
1. in an embodiment of the present invention, the current protection module includes: the current protection circuit comprises a main chip, a triode connected with the main chip, a current protection threshold value design unit and a differential comparator chip; a plurality of groups of differential comparators which correspond to each power switch circuit in the external multi-path PFC module one by one are arranged in the differential comparator chip; the first input end of the differential comparator is connected with the corresponding power switch circuit, the second input end of the differential comparator is connected with the current protection threshold value design unit, and the output end of the differential comparator is connected with the triode; the differential comparator chip samples the current sampling signal of each power switch circuit, and when any corresponding numerical value exceeds a current protection threshold value, the triode is controlled to be conducted; when the triode is conducted, the main chip determines that the current of the multiple PFC modules is abnormal and executes current protection processing. Because the current conditions of a plurality of circuits can be monitored simultaneously through one current protection module, a plurality of current protection modules are not required to be arranged, and the product cost is lower.
2. The embodiment of the invention provides a novel current protection module which can monitor the current condition of each power switch circuit in a multi-path PFC module at the same time and inform a main chip of current protection processing when the current abnormity is monitored. And then, specifically analyzing which path or paths of power switch circuits are abnormal according to requirements. Therefore, the novel current protection module provided by the embodiment of the invention can solve the current protection function of three-path or two-path staggered active PFC on the variable-frequency air conditioner driver, so that the variable-frequency air conditioner driver can stably and reliably work.
3. The current protection module used in the embodiment of the invention only needs one differential comparator chip, one triode, one main chip and one current protection threshold value design unit, can monitor the current conditions of a plurality of power switch circuits simultaneously through one current protection circuit, and has the advantages of high integration level, simple connection and greatly reduced product cost.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Those of ordinary skill in the art will understand that: all or part of the steps for realizing the method embodiments can be completed by hardware related to program instructions, the program can be stored in a computer readable storage medium, and the program executes the steps comprising the method embodiments when executed; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
Finally, it is to be noted that: the above description is only a preferred embodiment of the present invention, and is only used to illustrate the technical solutions of the present invention, and not to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims (7)

1. A current protection module, comprising:
the current protection circuit comprises a main chip, a triode, a current protection threshold value design unit and a differential comparator chip with a plurality of groups of differential comparators;
wherein the differential comparator comprises a first input terminal, a second input terminal and an output terminal;
at least two groups of first differential comparators in the multiple groups of differential comparators correspond to at least two power switch circuits in an external multi-path PFC module one to one;
for any one of the first differential comparators, a first input end of the first differential comparator is connected with the corresponding power switch circuit, a second input end of the first differential comparator is connected with the current protection threshold value design unit, and an output end of the first differential comparator is connected with the triode;
the triode is connected with the main chip;
the differential comparator chip is used for sampling a current sampling signal of each power switch circuit; when the value corresponding to any one current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit, controlling the triode to be conducted;
the main chip is used for determining that the current of the multi-path PFC module is abnormal and executing current protection processing when the triode is conducted;
the current protection threshold value design unit includes: the circuit comprises a first capacitor, a second capacitor, a third capacitor, a first resistor and a second resistor;
the first end of the first capacitor is connected with a VCC pin of the differential comparator chip, and the second end of the first capacitor is grounded;
the first end of the second capacitor is connected with the VCC pin, and the second end of the second capacitor is grounded;
the first end of the third capacitor is respectively connected with the second input end of each first differential comparator, and the second end of the third capacitor is grounded;
the first end of the first resistor is connected with the first end of the third capacitor, and the second end of the first resistor is grounded;
the first end of the second resistor is connected with the VCC pin, and the second end of the second resistor is connected with the first end of the third capacitor;
correspondingly, the current protection threshold value accords with a formula I;
the first formula comprises: v0＝[R1/(R1+R2)]×U
Wherein, V0For the current protection threshold value, R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, and U is the voltage value at the VCC pin;
further comprising: at least two third resistors and at least two fourth capacitors which are in one-to-one correspondence with the at least two groups of first differential comparators;
the first end of any one third resistor is connected with the first input end of the corresponding first differential comparator, and the second end of the third resistor is connected with the power switch circuit corresponding to the corresponding first differential comparator;
the first end of any one fourth capacitor is connected with the first input end of the corresponding first differential comparator, and the second end of the fourth capacitor is grounded;
further comprising: a fifth capacitor, a fourth resistor and a fifth resistor;
the first end of the fifth capacitor is connected with the triode, and the second end of the fifth capacitor is grounded;
the first end of the fourth resistor is connected with the first end of the fifth capacitor, and the second end of the fourth resistor is connected with the main chip;
and the first end of the fifth resistor is connected with the second end of the fourth resistor, and the second end of the fifth resistor is grounded.
2. The current protection module of claim 1,
the triode is a PNP triode;
the first input end is an In-pin, and the second input end is an In + pin;
the output end of any one of the first differential comparators is connected with the base electrode of the PNP triode;
the main chip is connected with the collector of the PNP triode;
the emitting electrode of the PNP triode is connected with external voltage;
in a corresponding manner, the first and second electrodes are,
the differential comparator chip is used for outputting a low level signal to the base electrode of the PNP triode when the value corresponding to any current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit;
the PNP triode is used for outputting a high-level signal to the main chip through a collector when a base electrode inputs a low-level signal to enable the external voltage to be conducted from an emitter electrode to the collector electrode;
and the main chip is used for determining that the current abnormality occurs in the multi-path PFC module when a high-level signal is input.
3. The current protection module of claim 1,
the triode is an NPN triode;
the first input end is an In + pin, and the second input end is an In-pin;
the output end of any one of the first differential comparators is connected with the base electrode of the NPN triode;
the main chip is connected with an emitting electrode of the NPN triode;
the collector of the NPN triode is connected with external voltage;
in a corresponding manner, the first and second electrodes are,
the differential comparator chip is used for outputting a high-level signal to the base electrode of the NPN triode when the value corresponding to any current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit;
the NPN triode is used for outputting a high-level signal to the main chip through an emitter when a base electrode inputs a high-level signal so as to enable the external voltage to be conducted from a collector electrode to the emitter electrode;
and the main chip is used for determining that the current abnormality occurs in the multi-path PFC module when a high-level signal is input.
4. Current protection module according to one of claims 1 to 3,
the number of the groups of the differential comparators is larger than the number of the at least two power switch circuits;
and the first input end and the second input end of other differential comparators in the multiple groups of differential comparators are connected with external voltage.
5. A current protection system, comprising:
a multi-PFC module comprising at least two power switching circuits, and a current protection module according to any one of claims 1 to 4;
the multi-path PFC module is used for outputting the current sampling signals of the power switch circuits to the current protection module.
6. The current protection system of claim 5,
the power switching circuit includes: the IGBT switching tube, the diode and the sixth resistor;
the grid electrode of the IGBT switching tube inputs a PWM signal, the emitting electrode outputs a current sampling signal, and the collecting electrode is connected with the anode of the diode;
and the first end of the sixth resistor is connected with the emitter of the IGBT switching tube, and the second end of the sixth resistor is grounded.
7. A current protection method based on the current protection module according to any one of claims 1 to 4, comprising:
sampling current sampling signals of each power switch circuit in the multi-path PFC module by using the differential comparator chip;
when the value corresponding to any one current sampling signal exceeds the current protection threshold value determined by the current protection threshold value design unit, the triode is controlled to be conducted by using the differential comparator chip;
and when the triode is conducted, the main chip is utilized to determine that the multiple PFC modules have abnormal current and execute current protection processing.
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