CN115021539B - Circuit structure for preventing current backflow - Google Patents
Circuit structure for preventing current backflow Download PDFInfo
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- CN115021539B CN115021539B CN202210947645.0A CN202210947645A CN115021539B CN 115021539 B CN115021539 B CN 115021539B CN 202210947645 A CN202210947645 A CN 202210947645A CN 115021539 B CN115021539 B CN 115021539B
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- power switch
- switch tube
- voltage
- operational amplifier
- circuit
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- 230000003044 adaptive effect Effects 0.000 claims abstract description 12
- 230000002265 prevention Effects 0.000 claims abstract description 11
- 239000000758 substrate Substances 0.000 claims description 3
- 230000003071 parasitic effect Effects 0.000 claims description 2
- 230000002262 irrigation Effects 0.000 abstract description 5
- 238000003973 irrigation Methods 0.000 abstract description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 229910052744 lithium Inorganic materials 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000002457 bidirectional effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
Images
Classifications
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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
- H02H3/18—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 reversal of direct current
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- 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
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
-
- 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
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0012—Control circuits using digital or numerical techniques
-
- 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
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- 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
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
- Direct Current Feeding And Distribution (AREA)
- Continuous-Control Power Sources That Use Transistors (AREA)
Abstract
The invention relates to a protection circuit, in particular to a circuit structure for preventing current backflow. The circuit comprises a power switch tube, a comparator and a front-end drive circuit. The IN end of the power switch tube is connected with the IN-phase input end of the comparator, the OUT end of the power switch tube is connected with the reverse phase input end of the comparator, the output end of the comparator is IN adaptive connection with the pre-drive circuit, and the pre-drive circuit is IN adaptive connection with the power switch tube. The operational amplifier is characterized by further comprising an operational amplifier, wherein the feedback end of the operational amplifier is connected with the OUT end of the power switch tube, the voltage input end of the operational amplifier is connected with an input voltage, the value of the input voltage is lower than that of the IN end of the power switch tube, and the output end of the operational amplifier S1 is connected with the pre-drive circuit IN an adaptive mode. The circuit structure has low power consumption during normal work, and the problem of failure of reverse irrigation prevention can be avoided.
Description
Technical Field
The invention relates to a protection circuit between a power supply conversion output end and a lithium battery charging input end, in particular to a circuit structure for preventing current backflow.
Background
With the development of science and technology, most new energy automobiles and little wireless earphones are internally provided with lithium batteries as sources of internal electric energy. In such a wide application scenario, in the face of various complicated charging environments, various protection circuits need to be arranged between the power conversion output end and the input end of lithium battery charging. Preventing current from flowing backwards is also one of the critical protection functions.
At present, the commonly used anti-reverse-filling protection structures are mainly of two types, the first type is realized by adding a natural anti-reverse-filling power device between a power supply conversion output end and a lithium battery charging end, and a typical representative of the device is a power-level Schottky diode. The first type of anti-reverse-flow protection structure is shown IN fig. 1, a power switch tube M1 can control the switching state thereof through a front-end driving structure, a power diode D1 is conducted when forward opening is required (an IN end is higher than an OUT end voltage), and is closed when reverse flow prevention is required (an OUT end is higher than an IN end voltage). The structure utilizes the natural forward conduction characteristic of the diode, and the structure is simple. However, the forward conduction voltage drop of the diode is large, and the power consumption is too high in the normal working process. And the second type is to set up a control system consisting of a driving module, a power switch module and a voltage sampling comparison module, so that the power switch module is ensured to be cut off in time when the voltage of the battery end is higher than that of the power conversion output end, and reverse filling prevention protection is realized. The second type of anti-reverse-flow protection structure is shown in fig. 2, and is composed of a comparator CMP, a front-end drive circuit Driver and a power switch tube M1. The power switch tube M1 is formed by connecting two identical MOS tubes back to back in series, and when the power switch tube M1 is in a cut-off state, bidirectional current cut-off can be ensured. Compared with the first class of structures, the second class of anti-reverse-filling structure selects back-to-back MOS tubes to replace the MOS tubes + diodes in the first class, and has smaller conduction voltage drop and lower conduction loss when in forward conduction. And setting the overturning threshold value of the comparator to be slightly higher than the voltage of the IN terminal at the OUT terminal, outputting a signal to a front-end drive circuit Driver when the comparator CMP detects that the voltage of the OUT terminal is higher than the voltage of the IN terminal, and closing a power switch tube M1 to realize the function of preventing reverse irrigation. The specific working process is as follows: if the voltage of the OUT end is slightly higher than that of the IN end, the reverse irrigation prevention is judged to be triggered, and the comparator CMP outputs a control signal to the front driving circuit Driver to close the power switch tube M1. Meanwhile, the judgment threshold value of the comparator CMP is adjusted to be that the OUT terminal voltage is slightly lower than the IN terminal voltage; when the voltage at the OUT terminal is slightly lower than that at the IN terminal, the comparator CMP outputs a control signal to the pre-Driver circuit Driver to turn on the power switch tube M1 again. However, IN practical applications, IN order to prevent the false triggering of the anti-backflow function (for example, when the OUT terminal voltage value at a certain moment collected by the comparator CMP is higher than the IN terminal voltage due to external signal interference), the comparator flip threshold hysteresis is generally designed. However, there is a delay from the triggering of the anti-reverse-flow function to the change of the state of the power switch M1 due to the comparator flip threshold hysteresis. If the power switch tube M1 is not closed IN time within the delay time, the voltage of the IN end can rise along with the voltage of the OUT end through the conducted power switch tube M1, and therefore the anti-reverse-filling function is invalid.
Disclosure of Invention
The invention aims to solve the technical problem of providing a current reverse-filling prevention circuit structure which has low power consumption during normal work and does not have the problem of reverse-filling prevention failure.
In order to solve the problems, the following technical scheme is provided:
the circuit structure for preventing current backflow comprises a power switch tube M1, a comparator and a front-end drive circuit. The IN end of the power switch tube M1 is connected with the IN-phase input end of the comparator, the OUT end of the power switch tube M1 is connected with the reverse phase input end of the comparator, the output end of the comparator is IN adaptive connection with the front driving circuit, and the front driving circuit is IN adaptive connection with the power switch tube M1 and used for driving the power switch tube M1 to be conducted. The power switch tube power supply circuit is characterized by further comprising an operational amplifier S1, wherein a feedback end B of the operational amplifier S1 is connected with an OUT end of the power switch tube M1, a voltage input end A of the operational amplifier S1 is connected with an input voltage, the value of the input voltage is lower than that of the IN end of the power switch tube M1, and the output end of the operational amplifier S1 is IN adaptive connection with a front-end driving circuit. The closed-loop negative feedback characteristic of the operational amplifier is adopted, so that the voltage of the feedback end B of the operational amplifier S1 follows the voltage of the voltage input end A, and the IN end voltage of the power switch tube M1 is ensured to be always larger than the OUT end voltage of the power switch tube M1.
The power switch tube M1 is formed by serially connecting two identical MOS tubes back to back.
The two MOS tubes are N-channel MOS tubes, diodes are respectively parasitized on the substrate levels of the two MOS tubes, the source electrodes of the two MOS tubes are connected IN series, the grid electrodes of the two MOS tubes are connected with the front-end driving circuit, the drain electrode of one MOS tube is the IN end of the power switch tube M1, and the drain electrode of the other MOS tube is the OUT end of the power switch tube M1.
The IN end of the power switch tube M1 is connected with one end of a resistor R, and the other end of the resistor R is connected with a voltage input end A of an operational amplifier S1 to form the input voltage.
One end of a resistor R connected with a voltage input end A of the operational amplifier S1 is connected with a current source I in series and then is grounded.
By adopting the scheme, the method has the following advantages:
because the circuit structure for preventing current backflow is added with the operational amplifier circuit on the second class structure in the background technology, the power consumption is smaller when the circuit structure is normally conducted compared with the first class structure in the background technology. IN addition, since the voltage of the feedback end B of the operational amplifier S1 follows the voltage of the voltage input end a, that is, the OUT terminal voltage of the power switch tube M1 is approximately equal to the input voltage, when interference occurs IN the outside, the OUT terminal voltage of the power switch tube M1 does not fluctuate, that is, the OUT terminal voltage of the power switch tube M1 is always lower than the IN terminal voltage. Therefore, the comparator is not required to be set to flip threshold hysteresis, once the voltage of the OUT end of the power switch tube M1 is higher than that of the IN end, the comparator can instantly close the front driving circuit, the power switch tube M1 is ensured to be IN a cut-off state, and the problem of failure of reverse filling prevention caused by the flip threshold hysteresis of the comparator is solved.
Drawings
FIG. 1 is a schematic circuit diagram of a first type of anti-back-filling structure in the background art;
FIG. 2 is a schematic circuit diagram of a second type of anti-reverse-flow structure in the prior art;
FIG. 3 is a schematic diagram of the circuit structure for preventing current backflow;
fig. 4 is a schematic diagram of the formation of the input voltage.
Detailed Description
As shown in fig. 3 and 4, the current backflow prevention circuit structure of the present invention includes a power switch M1, a comparator CMP, a pre-Driver circuit Driver, and an operational amplifier S1. The IN end of the power switch tube M1 is connected with the IN-phase input end of the comparator CMP, the OUT end of the power switch tube M1 is connected with the reverse phase input end of the comparator CMP, the output end of the comparator CMP is IN adaptive connection with the front driving circuit Driver, and the front driving circuit Driver is IN adaptive connection with the power switch tube M1 and used for driving the power switch tube M1 to be conducted. The feedback end B of the operational amplifier S1 is connected with the OUT end of the power switch tube M1, the voltage input end A of the operational amplifier S1 is connected with an input voltage, the value of the input voltage is lower than the voltage value of the IN end of the power switch tube M1, and the output end of the operational amplifier S1 is IN adaptive connection with the Driver of the front-end driving circuit.
By adopting the closed-loop negative feedback characteristic of the operational amplifier, the voltage of the feedback end B of the operational amplifier S1 follows the voltage of the voltage input end A, namely the voltage of the feedback end B is approximately equal to the voltage of the voltage input end A, and the value of the input voltage is lower than the voltage value of the IN end of the power switch tube M1. Therefore, it is ensured that the IN terminal voltage of the power switch tube M1 is always greater than the OUT terminal voltage of the power switch tube M1.
The power switch tube M1 is formed by serially connecting two identical MOS tube backs and backrests. The two MOS tubes are both N-channel MOS tubes, diodes are respectively arranged on the substrate levels of the two MOS tubes IN a parasitic mode, the source electrodes of the two MOS tubes are connected IN series, the grid electrodes of the two MOS tubes are connected with the front-end driving circuit, the drain electrode of one MOS tube is the IN end of the power switch tube M1, and the drain electrode of the other MOS tube is the OUT end of the power switch tube M1. The back-to-back MOS tubes have small conduction voltage drop and small conduction loss when conducting in the forward direction.
The IN end of the power switch tube M1 is connected with one end of a resistor R, and the other end of the resistor R is connected with a voltage input end A of an operational amplifier S1 to form the input voltage. The voltage drop is formed by the resistor R, so that the formed input voltage is ensured to be smaller than the voltage of the IN terminal, and the specific value of the input voltage is related to the resistance value of the resistor R.
One end of a resistor R connected with the voltage input end A of the operational amplifier S1 is connected with the current source I in series and then is grounded. The current source I is used for ensuring the stability of the input voltage because the current of the branch is the current output by the current source after the current source is switched on.
The specific principle is illustrated in three cases. For convenience of description, for example, the voltage of the voltage input terminal a of the operational amplifier S1 is lower than the voltage of the IN terminal by 50mV, the on-resistance of the power switch tube M1 is 25M Ω, and the inverse-flowing and inverting threshold of the comparator CMP is designed to be lower than the voltage of the OUT terminal by 10mV.
1. No load or light load condition. At this time, the operational amplifier S1 makes the power switch tube M1 work IN a saturation region through the closed-loop feedback of the OUT terminal, and the OUT terminal is kept at a state lower than the IN terminal by 50 mV. During no-load and light-load, although the power tube is in a saturation region, the power dissipation of the power switch tube M1 is very small, which is:
wherein the content of the first and second substances,
2. a heavy load condition. When the load current of the OUT end is greater than 2 amperes, the operational amplifier S1 exceeds the maximum output amplitude, the power switch tube M1 works in a linear region, the voltage of the OUT end is continuously reduced along with the increase of the load, and the power dissipation of the power switch tube M1 is as follows:
3. and preventing the reverse irrigation. When the OUT end is enabled to rise from a point 50mV lower than the IN end by an external power supply connected when the OUT end works, the operational amplifier S1 exceeds the minimum output amplitude, and the power switch tube M1 works IN a cut-off area. When the voltage of the OUT end rises to be 10mV lower than that of the IN end, the comparator CMP forcibly turns off the Driver of the front driving circuit, so that the power switch tube M1 is turned off at the same time, and the reverse irrigation prevention is realized.
Claims (5)
1. A circuit structure for preventing current backflow comprises a power switch tube M1, a comparator CMP and a front drive circuit Driver; the IN end of the power switch tube M1 is connected with the IN-phase input end of the comparator CMP, the OUT end of the power switch tube M1 is connected with the reverse-phase input end of the comparator CMP, the output end of the comparator CMP is IN adaptive connection with the front-end driving circuit Driver, and the front-end driving circuit Driver is IN adaptive connection with the power switch tube M1 and used for driving the power switch tube M1 to be conducted; the power switch tube driving circuit is characterized by further comprising an operational amplifier S1, wherein a feedback end B of the operational amplifier S1 is connected with an OUT end of the power switch tube M1, a voltage input end A of the operational amplifier S1 is connected with an input voltage, the value of the input voltage is lower than that of the IN end of the power switch tube M1, and the output end of the operational amplifier S1 is IN adaptive connection with a Driver of the front-end driving circuit; the closed-loop negative feedback characteristic of the operational amplifier is adopted, so that the voltage of the feedback end B of the operational amplifier S1 follows the voltage of the voltage input end A, and the IN end voltage of the power switch tube M1 is ensured to be always larger than the OUT end voltage of the power switch tube M1.
2. The circuit structure for preventing current backflow as claimed in claim 1, wherein the power switch M1 is formed by two identical MOS transistors connected in series back to back.
3. The current backflow prevention circuit structure as claimed IN claim 2, wherein the two MOS transistors are N-channel MOS transistors, and both of their substrate levels have a parasitic diode, the sources of the two MOS transistors are connected IN series, the gates of the two MOS transistors are connected to the pre-driver circuit, the drain of one of the MOS transistors is the IN terminal of the power switch transistor M1, and the drain of the other of the MOS transistors is the OUT terminal of the power switch transistor M1.
4. The current backflow prevention circuit structure as claimed IN any one of claims 1 to 3, wherein an IN end of the power switch tube M1 is connected with one end of a resistor R, and the other end of the resistor R is connected with a voltage input end A of an operational amplifier S1 to form the input voltage.
5. The circuit structure for preventing current backflow as claimed in claim 4, wherein one end of the resistor R connected to the voltage input terminal A of the operational amplifier S1 is connected in series with the current source I and then grounded.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210947645.0A CN115021539B (en) | 2022-08-09 | 2022-08-09 | Circuit structure for preventing current backflow |
| PCT/CN2023/083232 WO2024031994A1 (en) | 2022-08-09 | 2023-03-23 | Current backflow preventing circuit structure |
| KR1020237014344A KR20240022436A (en) | 2022-08-09 | 2023-03-23 | Circuit structure to prevent current reverse flow |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210947645.0A CN115021539B (en) | 2022-08-09 | 2022-08-09 | Circuit structure for preventing current backflow |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115021539A CN115021539A (en) | 2022-09-06 |
| CN115021539B true CN115021539B (en) | 2022-11-04 |
Family
ID=83065878
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210947645.0A Active CN115021539B (en) | 2022-08-09 | 2022-08-09 | Circuit structure for preventing current backflow |
Country Status (3)
| Country | Link |
|---|---|
| KR (1) | KR20240022436A (en) |
| CN (1) | CN115021539B (en) |
| WO (1) | WO2024031994A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115021539B (en) * | 2022-08-09 | 2022-11-04 | 无锡力芯微电子股份有限公司 | Circuit structure for preventing current backflow |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6332601B2 (en) * | 2014-01-31 | 2018-05-30 | アルプス電気株式会社 | Semiconductor integrated circuit device |
| CN204967312U (en) * | 2015-08-07 | 2016-01-13 | 浙江亚能能源科技有限公司 | Charging device suitable for battery hot plug and prevent joining conversely |
| CN105244864B (en) * | 2015-11-18 | 2018-03-02 | 四川汇源光通信有限公司 | Counnter attack fills protection circuit |
| CN105703615A (en) * | 2016-04-13 | 2016-06-22 | 浪潮集团有限公司 | Anti-flow-backward design method for DC power supply redundant circuit |
| CN106130525A (en) * | 2016-07-28 | 2016-11-16 | 威胜电气有限公司 | One-way conduction circuit and the distribution line failure positioner made with this circuit |
| CN113381591A (en) * | 2021-07-22 | 2021-09-10 | 上海川土微电子有限公司 | High-side switch driving circuit for preventing reverse high voltage |
| CN113890333B (en) * | 2021-09-29 | 2022-07-08 | 赛卓电子科技(上海)股份有限公司 | High-voltage stabilizing circuit with anti-protection function |
| CN115021539B (en) * | 2022-08-09 | 2022-11-04 | 无锡力芯微电子股份有限公司 | Circuit structure for preventing current backflow |
-
2022
- 2022-08-09 CN CN202210947645.0A patent/CN115021539B/en active Active
-
2023
- 2023-03-23 WO PCT/CN2023/083232 patent/WO2024031994A1/en unknown
- 2023-03-23 KR KR1020237014344A patent/KR20240022436A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| KR20240022436A (en) | 2024-02-20 |
| WO2024031994A1 (en) | 2024-02-15 |
| CN115021539A (en) | 2022-09-06 |
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