CN114498545A - Overcurrent failure protection circuit and electronic equipment - Google Patents

Overcurrent failure protection circuit and electronic equipment Download PDF

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Publication number
CN114498545A
CN114498545A CN202111629956.4A CN202111629956A CN114498545A CN 114498545 A CN114498545 A CN 114498545A CN 202111629956 A CN202111629956 A CN 202111629956A CN 114498545 A CN114498545 A CN 114498545A
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CN
China
Prior art keywords
resistor
node
operational amplifier
failure protection
input end
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Pending
Application number
CN202111629956.4A
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Chinese (zh)
Inventor
褚艳伟
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Priority to CN202111629956.4A priority Critical patent/CN114498545A/en
Publication of CN114498545A publication Critical patent/CN114498545A/en
Pending legal-status Critical Current

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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
    • H02H3/08—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 responsive to excess current
    • H02H3/087—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 responsive to excess current for dc applications
    • 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
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • 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)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The embodiment of the invention relates to an overcurrent failure protection circuit and electronic equipment, comprising: a first amplifying unit, a second amplifying unit, a third amplifying unit, a driving unit and a control element; when the first amplification unit fails, an external input current signal obtains an amplification signal through the third amplification unit, an overcurrent failure protection signal is obtained after the circuit is conducted through the driving unit and is transmitted to the control element, and the control element receives the overcurrent failure protection signal to trigger a protection mechanism. Therefore, the overcurrent failure protection function of the circuit is realized.

Description

Overcurrent failure protection circuit and electronic equipment
Technical Field
The embodiment of the invention relates to the field of integrated circuits, in particular to an overcurrent failure protection circuit and electronic equipment.
Background
In the design of integrated circuits, overcurrent protection circuits play an increasingly large role in the safety performance of circuits. The application of the PFC circuit is most Power Factor Correction (PFC) circuits, which are mainly used to characterize the utilization efficiency of electronic products to electric energy. The higher the power factor, the higher the utilization efficiency of the electric energy.
At present, a PFC circuit utilizes a sampling circuit of a plurality of operational amplifiers, an output signal of an adjacent operational amplifier is turned over due to an excessive current of the operational amplifier, a Micro Control Unit (MCU) identifies an overcurrent protection signal, and then a driving signal is turned off, a system is locked, and a PFC power device and a rectifier bridge are protected from being burned. However, when the sampling circuit of the PFC circuit fails, the output signal of the adjacent operational amplifier cannot be inverted, and the MCU cannot recognize the overcurrent protection signal, which eventually causes the PFC power device and the rectifier bridge to be burned.
Disclosure of Invention
In view of this, in order to solve the technical problem of circuit device damage caused by overcurrent failure, embodiments of the present invention provide an overcurrent failure protection circuit and an electronic device.
In a first aspect, an embodiment of the present invention provides an overcurrent failure protection circuit, including:
a first amplifying unit, a second amplifying unit, a third amplifying unit, a driving unit and a control element;
the input end of the first amplifying unit is connected with the external current input end, and the output end of the first amplifying unit is connected with the first node and the first input end of the control element;
the input end of the second amplifying unit is connected to the first node, and the output end of the second amplifying unit is connected to the second input end of the control element;
the input end of the third amplifying unit is connected to the first node, and the output end of the third amplifying unit is connected to the input end of the driving unit;
the output end of the driving unit is connected to the third input end of the control element;
the output end of the control element is connected with an external device.
In one possible embodiment, the first amplification unit comprises: the circuit comprises a first operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor;
the positive input end of the first operational amplifier is connected to a first grounding end through a first resistor, the negative input end of the first operational amplifier is connected to a second node, and the output end of the first operational amplifier is connected to a first node;
one end of the second resistor is connected to the second node, and the other end of the second resistor is connected to the external current input end;
one end of the third resistor is connected to the first node, and the other end of the third resistor is connected to the second node;
one end of the fourth resistor is connected to the first node, and the other end is connected to the second ground terminal.
In one possible embodiment, the second amplification unit comprises: the second operational amplifier, the fifth resistor and the sixth resistor;
the positive input end of the second operational amplifier is connected with the power supply bias end, the reverse input end of the second operational amplifier is connected with the third node, and the output end of the second operational amplifier is connected with the second input end of the control element;
one end of the fifth resistor is connected to the first node, and the other end of the fifth resistor is connected to the third node;
one end of the sixth resistor is connected to the third node, and the other end is connected to the third ground terminal.
In one possible embodiment, the third amplification unit comprises: a third operational amplifier, a seventh resistor, an eighth resistor and a ninth resistor;
the positive input end of the third operational amplifier is connected with one end of a seventh resistor, and the other end of the seventh resistor is connected with the first node; the inverting input end of the third operational amplifier is connected to the fourth node, and the output end of the third operational amplifier is connected to the input end of the driving unit;
one end of the eighth resistor is connected to the fourth node, and the other end of the eighth resistor is connected to the fourth ground terminal;
one end of the ninth resistor is connected to the fourth node, and the other end of the ninth resistor is connected to the output end of the third operational amplifier.
In one possible embodiment, the driving unit includes: a first driving subunit and a second driving subunit;
the input end of the first driving subunit is connected to the output end of the third amplifying unit, the output end of the first driving subunit is connected to the input end of the second driving subunit, and the output end of the second driving subunit is connected to the third input end of the control element.
In one possible embodiment, the first driving subunit includes: a tenth resistor, a first controllable element, and an eleventh resistor;
one end of the tenth resistor is connected to the output end of the third amplifying unit, and the other end of the tenth resistor is connected to the control end of the first controllable element;
the first end of the first controllable element is connected to the first power signal end, the second end of the first controllable element is connected to one end of the eleventh resistor and the output end of the first driving subunit, and the other end of the eleventh resistor is connected to the fifth ground end.
In one possible embodiment, the second driving subunit includes: a twelfth resistor, a second controllable element, and a thirteenth resistor;
one end of the twelfth resistor is connected to the output end of the first driving subunit, and the other end of the twelfth resistor is connected to the control end of the second controllable element;
the first end of the second controllable element is connected to one end of the thirteenth resistor, the other end of the thirteenth resistor is connected to the sixth ground terminal, and the second end of the second controllable element is connected to the second power signal terminal and the third input terminal of the control element.
In a second aspect, an embodiment of the present invention provides an electronic device, where the electronic device includes the overcurrent failure protection circuit in any one of the first aspects.
According to the overcurrent failure protection circuit and the electronic equipment provided by the embodiment of the invention, the first amplification unit, the second amplification unit, the third amplification unit, the driving unit and the control element are arranged, under the condition that the first amplification unit fails, the third amplification unit outputs the amplification signal, so that the driving unit is conducted and outputs the low-level overcurrent failure protection signal, and the control element triggers the overcurrent failure protection mechanism, so that the circuit device damage caused by the failure of the amplification unit is effectively avoided, and the overcurrent failure protection function is realized.
Drawings
Fig. 1 is a schematic structural diagram of a first overcurrent failure protection circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a second overcurrent failure protection circuit according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a third overcurrent failure protection circuit according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely 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. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
For the convenience of understanding of the embodiments of the present invention, the following description will be further explained with reference to specific embodiments, which are not to be construed as limiting the embodiments of the present invention.
The Over Current Protection (OCP) is a Protection method for operating a Protection device when a Current exceeds a predetermined maximum value. In circuit design, electronic devices have their own current ratings that are not allowed to be exceeded or that would otherwise burn out the device. And an overcurrent protection mechanism is adopted, and when the current exceeds the set current, the equipment is automatically powered off so as to protect the equipment or give an alarm signal.
Fig. 1 is a schematic structural diagram of a first overcurrent failure protection circuit according to an embodiment of the present invention. The subject of the overcurrent failure protection circuit may be, but is not limited to, an overcurrent protection device. As shown in fig. 1, the overcurrent failure protection circuit specifically includes:
a first amplification unit 11, a second amplification unit 12, a third amplification unit 13 and a drive unit 14 and a control element 15.
Further, the overcurrent failure protection circuit further includes a first node (hereinafter, referred to as P1 collectively), where the node may be understood as a connection point formed by connecting two cells or three cells, for example, P1 is an electrical connection point formed by connecting the first amplifying cell with the second amplifying cell and the third amplifying cell.
The internal circuit structure of the first overcurrent failure protection circuit provided by the embodiment of the invention comprises:
the input end of the first amplifying unit 11 is connected to the external current input end, and the output end is connected to the first node P1 and the first input end of the control element 15;
the input terminal of the second amplifying unit 12 is connected to the first node P1, and the output terminal is connected to the second input terminal of the control element 15;
the input end of the third amplifying unit 13 is connected to the first node P1, and the output end is connected to the input end of the driving unit 14;
the output of the driving unit 14 is connected to a third input of the control element 15;
the output of the control element 15 is connected to an external device.
When the circuit works normally, when overlarge current is input, the output high-level signal is obtained through the first amplification unit, the amplified high-level signal is obtained through the third amplification unit, the output high-level signal does not meet the starting voltage condition of the driving unit at the moment, the driving unit is not conducted, the high-level signal is kept unchanged through the signal output by the driving unit, and the control element receives the high-level signal output by the driving unit and keeps the normal working state. Meanwhile, the high level signal output by the first amplification unit passes through the second amplification unit to change the high level signal in the initial state, the low level signal is obtained through signal inversion, the control element receives the low level signal output by the second amplification unit to trigger an overcurrent protection mechanism, the operation logic of a circuit system is closed, the system is locked, a circuit device is prevented from being damaged due to overlarge current, and the overcurrent protection function is realized.
When the first amplifying unit fails, an externally input overlarge current is changed into a low level signal after passing through the first amplifying unit, the second amplifying unit keeps a high level output signal unchanged after receiving the low level signal, the control element keeps the principle working state unchanged after receiving the high level signal output by the second amplifying unit, and an overcurrent failure protection mechanism cannot be triggered. Meanwhile, the low-level signal output by the first amplification unit is amplified by the third amplification unit to still obtain a low-level signal. The low level signal reaches the starting voltage value of the driving unit, so that the driving unit is conducted. The driving unit outputs a low level signal, the control element receives the low level signal output by the driving unit and then triggers an overcurrent failure protection mechanism, the operation logic of the circuit system is closed, the system is locked, the circuit device is prevented from being damaged due to failure of the first amplifying unit and overlarge current, and the overcurrent protection function is realized.
The overcurrent failure protection circuit provided by the embodiment of the invention sets the first amplification unit, the second amplification unit, the third amplification unit, the driving unit and the control element. Through the combined action of the third amplification unit and the drive unit, when the first amplification unit fails, the circuit can obtain a low level signal after being amplified by the third amplification unit, so that the conduction condition of the drive unit is achieved, the low level signal is output, the control element receives the low level signal to trigger an overcurrent failure protection mechanism, the circuit is closed, the system is locked, and the overcurrent failure protection function is realized.
In an alternative of the embodiment of the present invention, the first amplification unit includes: the circuit comprises a first operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor; the positive input end of the first operational amplifier is connected to a first grounding end through a first resistor, the negative input end of the first operational amplifier is connected to a second node, and the output end of the first operational amplifier is connected to a first node; one end of the second resistor is connected to the second node, and the other end of the second resistor is connected to the external current input end; one end of the third resistor is connected to the first node, and the other end of the third resistor is connected to the second node; one end of the fourth resistor is connected to the first node, and the other end is connected to the second ground terminal.
In an alternative of the embodiment of the present invention, the second amplification unit includes: the second operational amplifier, the fifth resistor and the sixth resistor; the positive input end of the second operational amplifier is connected with the power supply bias end, the reverse input end of the second operational amplifier is connected with the third node, and the output end of the second operational amplifier is connected with the second input end of the control element; one end of the fifth resistor is connected to the first node, and the other end of the fifth resistor is connected to the third node; one end of the sixth resistor is connected to the third node, and the other end is connected to the third ground terminal.
In an alternative of the embodiment of the present invention, the third amplification unit includes: a third operational amplifier, a seventh resistor, an eighth resistor and a ninth resistor; the positive input end of the third operational amplifier is connected with one end of a seventh resistor, and the other end of the seventh resistor is connected with the first node; the inverting input end of the third operational amplifier is connected to the fourth node, and the output end of the third operational amplifier is connected to the input end of the driving unit; one end of the eighth resistor is connected to the fourth node, and the other end of the eighth resistor is connected to the fourth ground terminal; one end of the ninth resistor is connected to the fourth node, and the other end of the ninth resistor is connected to the output end of the third operational amplifier.
In an alternative of the embodiment of the invention, the drive unit comprises: a first driving subunit and a second driving subunit; the input end of the first driving subunit is connected to the output end of the third amplifying unit, the output end of the first driving subunit is connected to the input end of the second driving subunit, and the output end of the second driving subunit is connected to the third input end of the control element.
In an alternative of the embodiment of the invention, the first driving subunit comprises: a tenth resistor, a first controllable element, and an eleventh resistor; one end of the tenth resistor is connected to the output end of the third amplifying unit, and the other end of the tenth resistor is connected to the control end of the first controllable element; the first end of the first controllable element is connected to the first power signal end, the second end of the first controllable element is connected to one end of the eleventh resistor and the output end of the first driving subunit, and the other end of the eleventh resistor is connected to the fifth ground end.
In an alternative of the embodiment of the present invention, the second driving subunit includes: a twelfth resistor, a second controllable element, and a thirteenth resistor; one end of the twelfth resistor is connected to the output end of the first driving subunit, and the other end of the twelfth resistor is connected to the control end of the second controllable element; the first end of the second controllable element is connected to one end of the thirteenth resistor, the other end of the thirteenth resistor is connected to the sixth ground terminal, and the second end of the second controllable element is connected to the second power signal terminal and the third input terminal of the control element.
Hereinafter, the first amplification unit will include: the first operational amplifier, first resistance, second resistance, third resistance and fourth resistance, the second amplification unit includes: a second operational amplifier, a fifth resistor, and a sixth resistor, the driving unit including: the first driving subunit and the second driving subunit, and the control element are described as an example. The resistor in the embodiment of the present invention represents a resistor device, and may be represented by a resistor but is not limited to a representation of a resistor device. Referring to fig. 2, a schematic structural diagram of a second overcurrent failure protection circuit according to an embodiment of the present invention is shown. The overcurrent failure protection circuit is explained on the basis of the first overcurrent failure protection circuit. As shown in fig. 2, the method specifically includes:
a first operational amplifier (hereinafter referred to as a1), a first resistor (hereinafter referred to as R1), a second resistor (hereinafter referred to as R2), a third resistor (hereinafter referred to as R3), and a fourth resistor (hereinafter referred to as R4);
the positive input end of the first operational amplifier a1 is connected to the first ground end through the first resistor R1, the negative input end is connected to the second node P2, and the output end is connected to the first node P1;
one end of the second resistor R2 is connected to the second node P2, and the other end is connected to the external current input end;
one end of the third resistor R3 is connected to the first node P1, and the other end is connected to the second node P2;
one end of the fourth resistor R4 is connected to the first node P1, and the other end is connected to the second ground terminal.
In the present embodiment, the first operational amplifier, the first resistor, the second resistor, the third resistor, and the fourth resistor constitute a first amplification unit.
According to the example shown in fig. 2, in a possible specific example scenario, when an excessive current is inputted from the outside in a normal operation state of the first operational amplifier a1 in the circuit, a proportional amplification voltage signal is obtained by the first operational amplifier a1, wherein the resistances of the second resistor R2 and the third resistor R3 are set to obtain a proportional amplification output voltage. When the input current is too large, the voltage passing through the first resistor R1 and the fourth resistor R4 is pulled to a low level state through the pull-down action of the first resistor R1 and the fourth resistor R4, and a local circuit protection action is realized.
As shown in fig. 2, the overcurrent failure protection circuit specifically further includes:
a second operational amplifier (hereinafter referred to as a2), a fifth resistor (hereinafter referred to as R5), and a sixth resistor (hereinafter referred to as R6);
the positive input terminal of the second operational amplifier A2 is connected to the power supply bias terminal (hereinafter referred to as V)F2) An inverting input terminal is connected to a third node (hereinafter referred to as P3), and an output terminal is connected to a second input terminal of a control element (hereinafter referred to as MCU);
one end of the fifth resistor R5 is connected to the first node P1, and the other end is connected to the third node P3;
one end of the sixth resistor R6 is connected to the third node P3, and the other end is connected to the third ground terminal.
In the present embodiment, the second operational amplifier, the fifth resistor, and the sixth resistor constitute a second amplifying unit.
In a possible example, when the external current is too large, after the first amplifying unit outputs the proportional amplifying voltage signal, the voltage of the inverting input terminal of the second operational amplifier a2 is gradually greater than the bias voltage V of the forward input terminal under the voltage division effect of the fifth resistor and the sixth resistorF2When the voltage at the reverse input end of the second operational amplifier A2 is greater than the bias voltage V at the forward input endF2At this time, the output voltage is inverted from a high level signal to a low level signal. After the control element MCU receives the low level signal, an overcurrent failure protection mechanism is triggered, the system operation is closed, a circuit device is protected from being damaged, and the overcurrent failure protection function of the circuit is realized.
As shown in fig. 2, the overcurrent failure protection circuit specifically further includes:
a third operational amplifier (hereinafter referred to as a3), a seventh resistor (hereinafter referred to as R7), an eighth resistor (hereinafter referred to as R8), and a ninth resistor (hereinafter referred to as R9);
the positive input end of the third operational amplifier a3 is connected to one end of a seventh resistor R7, and the other end of the seventh resistor R7 is connected to the first node P1; the inverting input terminal of the third operational amplifier a1 is connected to the fourth node (hereinafter referred to as P4), and the output terminal is connected to the input terminal of the driving unit 14;
one end of the eighth resistor R8 is connected to the fourth node P4, and the other end is connected to the fourth ground terminal;
the ninth resistor R9 has one end connected to the fourth node P4 and the other end connected to the output terminal of the third operational amplifier A3.
The first node is an electrical connection point formed by the first amplification unit, the second amplification unit and the third amplification unit, the second node is an electrical connection point formed by the first operational amplifier in the first amplification unit, the second resistor and the third resistor, and the third node is an electrical connection point formed by the second operational amplifier in the second amplification unit, the fifth resistor and the sixth resistor. The fourth node is an electric connection point formed by the third operational amplifier in the third amplifying unit, the eighth resistor and the ninth resistor. In the present embodiment, the third operational amplifier, the seventh resistor, the eighth resistor, and the ninth resistor constitute a third amplifying unit.
In a possible example, when the external input current is too large and the first amplifying unit 11 fails, the first amplifying unit 11 outputs a low-level signal, the forward input end of the third operational amplifier A3 obtains the low-level input signal under the voltage division effect of the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9 are used as proportional resistors of the third operational amplifier A3 to output the low-level signal amplified in the same proportion, the drive starting voltage of the adjacent driving unit is reached, and the low-level signal is output by the driving unit, so that the control element MCU triggers an overcurrent failure and protection mechanism, the system operation is closed, the protection circuit device is not damaged, and the overcurrent failure protection function of the circuit is realized.
As shown in fig. 2, the overcurrent failure protection circuit specifically further includes:
a first drive subunit 21 and a second drive subunit 22;
the input end of the first driving subunit 21 is connected to the output end of the third amplifying unit 13, the output end of the first driving subunit 21 is connected to the input end of the second driving subunit 22, and the output end of the second driving subunit 22 is connected to the third input end of the control element MCU.
In this embodiment, the first driving subunit and the second driving subunit constitute a driving unit.
In one possible example, when the current input outside the circuit is too large and the first amplifying unit 11 fails, a low level signal is output through the first amplifying unit 11 and a low level signal is output under the same-scale amplification of the third amplifying unit 13. The low level signal reaches the turn-on voltage of the first driving subunit 21, the first driving subunit 21 is turned on and outputs a high level signal, and the high level signal reaches the turn-on voltage of the second driving subunit 22 at the same time, so that the second driving subunit 22 is turned on and outputs a low level signal. The control element MCU triggers an overcurrent failure protection mechanism after receiving the low level signal, the system is closed, the circuit device is protected from being damaged due to the failure of the circuit device, and the overcurrent failure protection function of the circuit is realized.
According to the overcurrent failure protection circuit provided by the embodiment of the invention, by arranging the first operational amplifier A1, the second operational amplifier A2, the third operational amplifier A3, the first driving subunit 21, the second driving subunit 22 and the control element MCU, when an external current is too large, an amplification signal is output by the first operational amplifier A1, so that the output signal of the second operational amplifier A2 is turned over, an overcurrent failure protection mechanism of the control element is triggered, and the overcurrent failure protection function is realized. When the first operational amplifier fails, the low level output by the first operational amplifier a1 is amplified in the same proportion by the third operational amplifier A3 to obtain a low level signal, so that the first driving subunit 21 and the second driving subunit 22 are conducted, and the second driving subunit 22 outputs a low level signal, thereby triggering an overcurrent failure protection mechanism of the control element, shutting down the system operation, protecting circuit devices from being damaged, and realizing an overcurrent failure protection function of the circuit.
Hereinafter, the first amplification unit will include: the first operational amplifier, first resistance, second resistance, third resistance and fourth resistance, the second amplification unit includes: a second operational amplifier, a fifth resistor, and a sixth resistor, the third amplifying unit including: third operational amplifier, seventh resistance, eighth resistance and ninth resistance, the first drive subunit includes: a tenth resistor, a first controllable element, and an eleventh resistor, the second drive subunit including: a twelfth resistor, a second controllable element, and a thirteenth resistor, the control element being described by way of example. Referring to fig. 3, a schematic structural diagram of a third overcurrent failure protection circuit provided in the embodiment of the present invention is shown. The overcurrent failure protection circuit is explained on the basis of the second overcurrent failure protection circuit. As shown in fig. 3, the method specifically further includes:
the first drive subunit 21 includes: a tenth resistor (hereinafter referred to as R10), a first controllable element (hereinafter referred to as T1), and an eleventh resistor (hereinafter referred to as R11);
one end of the tenth resistor R10 is connected to the output end of the third amplifying unit 13, and the other end is connected to the control end of the first controllable element T1;
a first terminal of the first controllable element T1 is connected to a first power signal terminal (hereinafter referred to as VCC), a second terminal is connected to one terminal of the eleventh resistor R11 and the output terminal of the first driving subunit 21, and the other terminal of the eleventh resistor R11 is connected to a fifth ground terminal.
The second driving subunit 22 includes: a twelfth resistor (hereinafter referred to as R12), a second controllable element (hereinafter referred to as T2), and a thirteenth resistor (hereinafter referred to as R13);
one end of the twelfth resistor R12 is connected to the output end of the first driving subunit 21, and the other end is connected to the control end of the second controllable element T2;
a first terminal of the second controllable element T2 is connected to one terminal of a thirteenth resistor R13, the other terminal of the thirteenth resistor R13 is connected to a sixth ground terminal, and a second terminal of the second controllable element T2 is connected to a second power signal terminal (hereinafter referred to as VCC) and a third input terminal of the control element MCU.
In this embodiment, the tenth resistor, the first controllable element, and the eleventh resistor constitute the first driving subunit, and the twelfth resistor, the second controllable element, and the thirteenth resistor constitute the second driving subunit.
In one possible design, when the external input current is too large and the first operational amplifier a1 fails to operate, a low signal is output after passing through the first operational amplifier a 1. The third operational amplifier a3 receives the low level signal and amplifies the low level signal in the same proportion to output a low level signal. The first controllable element T1 reaches the turn-on voltage under the action of the low level, and outputs a high level signal. The second controllable element T2 reaches the turn-on voltage under the action of the high level signal, and outputs a low level signal. After receiving the low level signal, the adjacent control element MCU triggers a circuit overcurrent failure protection mechanism to close the system operation, so that circuit devices are protected from being damaged, and the overcurrent failure protection function of the circuit is realized.
The circuit overcurrent failure protection function is described in detail below with reference to specific example scenarios. In one possible example, the scheme can be applied to but not limited to air conditioning equipment. In this example circuit, the first controllable element includes, but is not limited to, a (PNP type) transistor T1, the second controllable element includes, but is not limited to, an (NPN type) transistor T2, and the control element includes, but is not limited to, a microcontroller MCU. In a Boost-PFC circuit, when bus current Im input from the outside is too large, under the voltage division action of a second resistor R2, an amplified high-level signal is output through a first operational amplifier A1, and under the pull-down action of a fourth resistor R4, voltage U0 output from the first operational amplifier A1 is kept unchanged at a low level. Under the action of in-phase proportional amplification, a third operational amplifier A3 outputs an in-phase proportional amplification signal U1, at this time, an output signal U1 is a high-level signal, but the output signal U1 does not reach the conduction voltage of a (PNP type) triode T1, an adjacent (NPN type) triode T2 is not conducted, the high-level signal is protected from changing, and the microcontroller MCU receives the high-level signal and keeps a normal working state from changing. At this time, the second operational amplifier a2 receives the high signal U0, and the output signal is inverted and changed from high to low. After receiving the low level signal, the microcontroller MCU triggers an overcurrent failure protection mechanism to close the system operation, so that circuit devices are protected from being damaged, and the overcurrent failure protection function of the circuit is realized.
When the external input bus current Im is too large and the first operational amplifier a1 fails to operate, a low level signal is output by the pull-down action of the fourth resistor R4 after passing through the first operational amplifier a 1. The low level signal can not cause the high level signal OC output by the second operational amplifier a2 to flip, and the microcontroller MCU will keep the normal operation state for the received OC signal. Meanwhile, the low-level signal U0 output from the first operational amplifier a1 is subjected to voltage division by the seventh resistor R7, and then subjected to proportional amplification by the third operational amplifier A3, so as to obtain a low-level signal U1. Under the voltage division effect of the tenth resistor R10, the conduction voltage of the (PNP) transistor T1 is reached, and the high level signal U2 is output. Under the voltage division effect of the twelfth resistor R12, the on-state voltage of the (NPN) transistor T2 is reached, and a low-level signal U3 is output. After receiving the low level signal U3, the microcontroller MCU triggers a circuit overcurrent failure protection mechanism to close the system operation, so that circuit devices are protected from being damaged, and the overcurrent failure protection function of the circuit is realized.
According to the overcurrent failure protection circuit provided by the embodiment of the invention, the first controllable element, the second controllable element, the tenth resistor, the eleventh resistor, the twelfth resistor and the thirteenth resistor are arranged in the driving unit, when the external current is too large and the first amplifying unit fails, the third amplifying unit outputs a low level signal, the first controllable element is started, and a high level signal is output. The second controllable element is conducted after receiving the high-level signal and outputs a low-level signal, an overcurrent failure protection mechanism of the control element MCU is triggered, the system operation is closed, and the overcurrent failure protection function of the circuit is realized.
Based on the overcurrent failure protection circuit provided by the embodiment, the invention also provides electronic equipment which comprises the overcurrent failure protection circuit provided by the embodiment.
In one possible design, the electronic device may be, but is not limited to, an air conditioning device, or any electronic device that requires the use of the over-current failure protection circuit configuration of the present invention.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (8)

1. An overcurrent failure protection circuit, comprising:
a first amplifying unit, a second amplifying unit, a third amplifying unit, a driving unit and a control element;
the input end of the first amplifying unit is connected to an external current input end, and the output end of the first amplifying unit is connected to a first node and a first input end of the control element;
the input end of the second amplifying unit is connected to the first node, and the output end of the second amplifying unit is connected to the second input end of the control element;
the input end of the third amplifying unit is connected to the first node, and the output end of the third amplifying unit is connected to the input end of the driving unit;
the output end of the driving unit is connected to the third input end of the control element;
the output end of the control element is connected with external equipment.
2. The overcurrent failure protection circuit of claim 1 wherein the first amplification unit comprises: the circuit comprises a first operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor;
the positive input end of the first operational amplifier is connected to a first grounding end through a first resistor, the negative input end of the first operational amplifier is connected to a second node, and the output end of the first operational amplifier is connected to the first node;
one end of the second resistor is connected to the second node, and the other end of the second resistor is connected to an external current input end;
one end of the third resistor is connected to the first node, and the other end of the third resistor is connected to the second node;
one end of the fourth resistor is connected to the first node, and the other end of the fourth resistor is connected to a second ground terminal.
3. The overcurrent failure protection circuit of claim 1 wherein the second amplification unit comprises: the second operational amplifier, the fifth resistor and the sixth resistor;
the positive input end of the second operational amplifier is connected with the power supply bias end, the reverse input end of the second operational amplifier is connected with the third node, and the output end of the second operational amplifier is connected with the second input end of the control element;
one end of the fifth resistor is connected to the first node, and the other end of the fifth resistor is connected to the third node;
one end of the sixth resistor is connected to the third node, and the other end of the sixth resistor is connected to a third ground terminal.
4. The overcurrent failure protection circuit of claim 1, wherein the third amplification unit comprises: a third operational amplifier, a seventh resistor, an eighth resistor and a ninth resistor;
a positive input end of the third operational amplifier is connected to one end of the seventh resistor, and the other end of the seventh resistor is connected to the first node; the inverting input end of the third operational amplifier is connected to a fourth node, and the output end of the third operational amplifier is connected to the input end of the driving unit;
one end of the eighth resistor is connected to the fourth node, and the other end of the eighth resistor is connected to a fourth ground terminal;
one end of the ninth resistor is connected to the fourth node, and the other end of the ninth resistor is connected to the output end of the third operational amplifier.
5. The overcurrent failure protection circuit of claim 1 wherein the drive unit comprises: a first driving subunit and a second driving subunit;
the input end of the first driving subunit is connected to the output end of the third amplifying unit, the output end of the first driving subunit is connected to the input end of the second driving subunit, and the output end of the second driving subunit is connected to the third input end of the control element.
6. The overcurrent failure protection circuit of claim 5 wherein the first drive subunit comprises: a tenth resistor, a first controllable element, and an eleventh resistor;
one end of the tenth resistor is connected to the output end of the third amplifying unit, and the other end of the tenth resistor is connected to the control end of the first controllable element;
the first end of the first controllable element is connected to a first power signal end, the second end of the first controllable element is connected to one end of the eleventh resistor and the output end of the first driving subunit, and the other end of the eleventh resistor is connected to a fifth ground end.
7. The overcurrent failure protection circuit of claim 5 wherein the second drive subunit comprises: a twelfth resistor, a second controllable element, and a thirteenth resistor;
one end of the twelfth resistor is connected to the output end of the first driving subunit, and the other end of the twelfth resistor is connected to the control end of the second controllable element;
the first end of the second controllable element is connected to one end of the thirteenth resistor, the other end of the thirteenth resistor is connected to a sixth ground terminal, and the second end of the second controllable element is connected to the second power signal terminal and the third input terminal of the control element.
8. An electronic device, characterized in that the electronic device comprises an overcurrent failure protection circuit as claimed in any one of claims 1 to 7.
CN202111629956.4A 2021-12-27 2021-12-27 Overcurrent failure protection circuit and electronic equipment Pending CN114498545A (en)

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