CN117411149A - Anti-backflow circuit, method, system and device for charging current - Google Patents
Anti-backflow circuit, method, system and device for charging current Download PDFInfo
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- CN117411149A CN117411149A CN202311721883.0A CN202311721883A CN117411149A CN 117411149 A CN117411149 A CN 117411149A CN 202311721883 A CN202311721883 A CN 202311721883A CN 117411149 A CN117411149 A CN 117411149A
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- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000001514 detection method Methods 0.000 claims abstract description 57
- 230000002265 prevention Effects 0.000 claims abstract description 16
- 230000000087 stabilizing effect Effects 0.000 claims description 42
- 238000001914 filtration Methods 0.000 claims description 23
- 239000003990 capacitor Substances 0.000 claims description 18
- 230000003405 preventing effect Effects 0.000 claims description 14
- 230000015556 catabolic process Effects 0.000 claims description 8
- 230000008859 change Effects 0.000 claims description 7
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 8
- 230000001276 controlling effect Effects 0.000 description 5
- 230000001052 transient effect Effects 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000004146 energy storage Methods 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
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- 230000001360 synchronised effect Effects 0.000 description 2
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- 238000013461 design Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
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Classifications
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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
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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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
- H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits
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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
- H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
Abstract
The application relates to the technical field of charging circuits, in particular to a backflow prevention circuit, method, system and device for charging current, wherein the circuit comprises a current detection module and a backflow switch module; the current detection module is used for detecting the current direction of the backflow switch module and changing the internal conduction mode according to the current direction so as to send a voltage-regulating direct current signal to the backflow switch module; and the backflow switch module is used for adjusting the pressure drop of the backflow switch module according to the voltage-regulating direct-current signal so as to control the connection or disconnection of the backflow switch module. The anti-backflow circuit has the beneficial effects that the anti-backflow of the charging current can be realized through a simple device, so that the circuit cost is reduced.
Description
Technical Field
The application relates to the technical field of charging circuits, in particular to a backflow prevention circuit, method, system and device for charging current.
Background
At present, the energy storage power supply product generally adopts a lithium battery for energy storage, a BUCK-BOOST synchronous rectification converter is mostly used for improving the conversion efficiency of a charging circuit, the problem that battery current flows backwards and returns to the charging circuit in the final charging stage or the period that the charging circuit stops is solved, and the product on the market at present mainly adopts a scheme of a special ORING controller and an MOS tube.
Therefore, how to reduce the current backflow prevention cost during charging is a technical problem to be solved.
Disclosure of Invention
The embodiment of the application provides a reverse flow preventing circuit, method, system and device for charging current, which can realize the reverse flow preventing of the charging current through a simple device, thereby reducing the circuit cost.
The first aspect of the present application provides a reverse current prevention circuit for charging current, comprising: the current detection module and the backflow switch module are used for detecting the current of the liquid crystal display;
the current detection module is used for detecting the current direction of the reverse flow switch module and changing the internal conduction mode according to the current direction;
the backflow switch module is used for adjusting the voltage drop of the backflow switch module according to the internal conduction mode of the current detection module so as to control the connection or disconnection of the backflow switch module;
the current detection module comprises an energy supply input end, a trigger output end, a first output end and a second output end, and the backflow switch module comprises a charging input end, a trigger input end, a first input end and a second input end;
the energy supply input end of the current detection module is connected with an external direct current signal source; the charging input end of the backflow switch module is connected with an external power supply circuit;
the trigger output end of the current detection module is connected with the trigger input end of the backflow switch module;
the first output end of the current detection module is connected with the first input end of the backflow switch module and is used for adjusting the internal voltage drop of the backflow switch module when the charging current flows backwards;
and the second output end of the current detection module is connected with the second input end of the backflow switch module and an external power load.
Through adopting above-mentioned technical scheme, use current detection module to acquire the current direction and judge whether the electric current flows backward, adjust the inside pressure drop of backward flow switch module when the electric current flows backward, make charging current cut-off through adjusting the pressure drop to the function of preventing flowing backward of electric current is realized with simple device.
Optionally, the circuit further comprises a filtering module;
the filtering module is used for generating an alternating current shunt and filtering interference signals;
one end of the filtering module is connected with the connection part of the direct current signal source and the current detection module, and the other end of the filtering module is connected with the connection part of the power supply circuit and the backflow switch module.
By adopting the technical scheme, an alternating current signal bypass is formed, and unnecessary interference signals are discharged through the filtering module, so that the stability of the signals is improved.
Optionally, the circuit further comprises a voltage stabilizing protection module;
the voltage stabilizing protection module is used for ensuring that the voltage drop of the backflow switch module is embedded to the breakdown voltage of the voltage stabilizing protection module, so that the reliability of the circuit is improved;
one end of the voltage stabilizing protection module is connected with the connection part of the first input end and the trigger input end, and the other end of the voltage stabilizing protection module is connected with the connection part of the charging input end and the charging output end.
By adopting the technical scheme, the internal access voltage of the backflow switch module is ensured to be embedded to the breakdown voltage of the voltage stabilizing protection module, so that the triggering end of the backflow switch module is protected from being damaged, and the reliability of a circuit is improved.
Optionally, the current detection module includes a first resistor, a second resistor, a third resistor, a first triode and a second triode;
one end of the first resistor is connected with the direct current signal source, the other end of the first resistor is connected with the collector electrode of the first triode and one end of the second resistor, and the other end of the second resistor is connected with the trigger input end of the backflow switch module;
the emitter of the first triode is connected with the first input end of the backflow switch module;
one end of the third resistor is connected with the connection part of the direct current signal source and the first resistor, and the other end of the third resistor is connected with the emitter of the second triode, the base electrode of the second triode and the base electrode of the first triode;
and the collector electrode of the second triode is connected with the second input end of the backflow switch module.
By adopting the technical scheme, the pull-up resistor is formed through the plurality of resistors, and when the current direction is normal, the trigger end of the Gao Daoguan switch module is pulled through the pull-up resistor, so that the charging current is normally output to the load, and meanwhile, the mirror image source current is formed through the two triodes, so that the conditions that the second triode is conducted and the first triode is disconnected are formed; once the current flows backward, the first triode is conducted, the second triode is cut off, the voltage drop between the first input end and the trigger input end of the backward flow switch module is approximately 0V, and therefore the charging current is cut off, and the backward flow preventing effect of the current is achieved.
Optionally, the backflow switch module comprises a MOS tube;
the source electrode of the MOS tube is connected with the emitter electrode of the first triode and the power supply circuit, the grid electrode of the MOS tube is connected with the other end of the second resistor, and the drain electrode of the MOS tube is connected with the collector electrode of the second triode and the power load.
By adopting the technical scheme, the voltage difference between the source electrode and the drain electrode of the MOS tube is close to 0V by using the current detection module, so that current backflow prevention is realized; meanwhile, as the charging current is transmitted through the channel of the MOS tube, the internal resistance of the MOS tube is small, so that the loss of the cut-off signal is also small.
Optionally, the filtering module includes a capacitor;
one end of the capacitor is connected with the connection part of the direct current signal source and the first resistor, and the other end of the capacitor is connected with the connection part of the power supply circuit and the MOS tube.
By adopting the technical scheme, the characteristics of alternating current and direct current resistance of the capacitor are utilized, the capacitor is used as a bypass capacitor of the anti-backflow circuit, unwanted interference signals are filtered, and the stability of the signals is improved.
Optionally, the voltage stabilizing protection module comprises a voltage stabilizing tube;
the positive electrode of the voltage stabilizing tube is connected with the junction of the first triode and the MOS tube, and the negative electrode of the voltage stabilizing tube is connected with the junction of the second resistor and the MOS tube.
By adopting the technical scheme, the voltage stabilizing protection module can adopt a voltage stabilizing tube as a grid protection device of the MOS tube, so that the voltage between the grid and the source of the MOS tube is ensured to be clamped to the breakdown voltage of the voltage stabilizing tube, and the reliability of the circuit is improved.
A second aspect of the present application provides a method for preventing backflow of a charging current, applied to a charging circuit, the method comprising:
controlling the charging circuit to be in a balance state, and judging whether charging current exists in the charging circuit or not;
if the charging current exists in the charging circuit, controlling the charging circuit to change from the balance state to the unbalance state;
if the charging circuit is in the unbalanced state, acquiring the current direction of the charging current;
and adjusting the internal conduction mode of the charging circuit according to the current direction, so as to control the conduction or disconnection of the charging circuit.
By adopting the technical scheme, after the current direction is detected, the internal device of the charging circuit is controlled to be conducted or disconnected according to the current direction, so that the charging circuit is disconnected in time when the current backflow phenomenon occurs, and the current backflow prevention effect is realized.
A third aspect of the present application provides a backflow prevention system for charging current, comprising:
the current detection module is used for controlling the charging circuit to be in a balanced state and judging whether charging current exists in the charging circuit or not;
the current detection module is further configured to control the charging circuit to change from the equilibrium state to an unbalanced state if the charging current exists in the charging circuit;
the current detection module is further configured to obtain a current direction of the charging current if the charging circuit is in the unbalanced state;
and the reverse flow switch module is used for adjusting the internal conduction mode of the charging circuit according to the current direction so as to control the conduction or disconnection of the charging circuit.
A fourth aspect of the present application provides a device carrying the circuit structure of the anti-backflow circuit of charging current described above.
In summary, the present application at least includes one of the following beneficial effects:
1. a pull-up resistor is formed through a plurality of resistors, when the current direction is normal, a trigger end of a Gao Daoguan switch module is pulled through the pull-up resistor, so that charging current is normally output to a load, and mirror image source current is formed through two triodes, so that the condition that a second triode is conducted and a first triode is disconnected is formed; once the current flows backward, the first triode is conducted, the second triode is cut off, the voltage difference between the charging input end and the charging output end of the backward flow switch module is close to 0V, the charging current is cut off, and the backward flow preventing effect of the current is achieved.
2. The MOS tube is used for transmitting the charging current through the MOS tube channel, so that the internal resistance of the MOS tube is small, and the loss of the signal caused by the operation of turning off the charging circuit when the current flows backward is also small, the circuit efficiency is improved, and the energy-saving and environment-friendly effects are realized.
3. The charging circuit provided by the application has excellent transient characteristics due to simple circuit structure, can achieve microsecond response speed in actual measurement, and has reliability in current backflow.
Drawings
Fig. 1 is a waveform diagram of a simulation signal of a reverse current prevention circuit for charging current according to an embodiment of the present application;
FIG. 2 is a block diagram of a reverse current prevention circuit for charging current according to an embodiment of the present disclosure;
FIG. 3 is an equivalent schematic diagram of a reverse current prevention circuit for charging current provided in an embodiment of the present application;
fig. 4 is a schematic circuit diagram of a reverse current prevention circuit for charging current according to an embodiment of the present application.
Detailed Description
At present, the energy storage power supply product generally adopts lithium battery energy storage, in order to improve the conversion efficiency of a charging circuit, a BUCK-BOOST synchronous rectification converter is mostly used, the problem that battery current flows backward and returns to the charging circuit at the end of charging or during the stop period of the charging circuit exists, and in order to solve the problem, two main solutions are available in the product on the market at present:
firstly, a diode is used as an anti-backflow isolation circuit, the circuit is simple, the cost is low, the transient response is quick, the voltage drop of the diode is generally larger, the diode loss cannot be ignored in the application of larger charging current, and the conversion efficiency is greatly influenced;
secondly, a scheme of adding an MOS tube by using a special ORING controller is adopted, so that the circuit is complex, the cost is high, the debugging is relatively complex, and the transient response is poor.
The anti-backflow circuit for the charging current can cut off the backflow current with very low loss, and achieves the anti-backflow function through a simple device with low cost, and also has very strong reliability because the circuit structure is relatively simple, so that the transient characteristic of the circuit is superior to that of a complex anti-backflow circuit, and the corresponding speed of microsecond level can be achieved in actual measurement.
The present application is described in further detail below with reference to the accompanying drawings.
Referring to fig. 1, fig. 1 is a waveform diagram of a simulation signal of a reverse current prevention circuit for charging current provided in an embodiment of the present application, the upper half of fig. 1 is a voltage waveform of an ac voltage source, and the amplitude of the voltage includes a positive voltage and a negative voltage, and a reverse current is simulated by the negative voltage of the ac signal. The lower half of fig. 1 is combined to see that after the alternating current signal passes through the anti-backflow circuit of the charging current of the application, the original alternating current signal is seen to form direct current signal output after passing through the anti-backflow circuit of the application, and the anti-backflow circuit of the charging current of the application is described to have the function of current backflow prevention.
Referring to fig. 2, fig. 2 is a block connection diagram of a reverse current prevention circuit for charging current according to an embodiment of the present application, including a current detection block 1 and a reverse current switch block 2, and the current detection block 1 and the reverse current switch block 2 are specifically described below:
the current detection module 1 is configured to detect a current direction of the reverse switch module 2, and change an internal conduction mode according to the current direction.
Regarding the current detection module 1: the current detection module 1 comprises a group of pull-up resistors and a pair of closing triodes, wherein the pull-up resistors are used for pulling up the direct current signal voltage to an external direct current signal source, the closing triodes are used for forming a group of mirror image source currents, the closing triodes are used as parameters of closing devices and are highly symmetrical, and when no current flows in the backward flow switch module 2, the mirror image source currents of the current detection module 1 are in a balanced state under the condition; and in case there is the electric current to flow in the backward flow switch module 2, balanced state can be broken, closes in the triode this moment, and one triode can switch on, and another triode can cut off, through the conduction condition of two triodes, can judge the direction of electric current, in the backward flow switch module 2, charge current's input and output carry out the pressure regulating simultaneously.
The backflow switch module 2 is configured to adjust a voltage drop of the backflow switch module 2 according to an internal conduction mode of the current detection module 1, so as to control on or off of the backflow switch module 2.
Regarding the backflow switch module 2: compared with a diode, the conduction voltage drop of the diode is usually above 0.7V, if the diode is directly used for anti-backflow, the conversion efficiency is lower, the loss of electric energy is also very high, and the method for preventing backflow of current by using the MOS tube provided by the application enables charging current to be transmitted through a channel of the MOS tube, the internal resistance is very low, and the loss is very low when the current backflow is stopped. In addition, because the grid of MOS pipe has symmetry after triggering, source electrode and drain electrode can carry out signal transmission in two directions promptly, this application is through the conduction mode of the close diode of current detection module 1, adjusts the voltage difference of the grid of MOS pipe and source electrode to approximately 0 for the MOS pipe is cut off, thereby has realized preventing the effect of electric current backward flow.
The following is a specific description of the connection relationship of the modules:
the current detection module 1 comprises an energy supply input end, a trigger output end, a first output end and a second output end, and the backflow switch module 2 comprises a charging input end, a trigger input end, a first input end and a second input end;
the energy supply input end of the current detection module 1 is connected with an external direct current signal source VCC; the charging input end of the backflow switch module 2 is connected with an external power supply circuit V+;
the trigger output end of the current detection module 1 is connected with the trigger input end of the backflow switch module 2;
the first output end of the current detection module 1 is connected with the first input end of the backflow switch module 2, and is used for adjusting the internal voltage drop of the backflow switch module 2 when charging current flows backwards;
the second output end of the current detection module 1 is connected with the second input end of the backflow switch module 2 and an external power load.
Specifically, the external dc signal source VCC is configured to supply power to the internal devices of the current detection module 1 through the power supply input end, and the external power supply circuit v+ may be an auxiliary winding or a bootstrap capacitor, and in actual application, may be a charger, and the external power load is an electric device such as a battery that needs to be charged by the charger. In the above description, it is mentioned that the reverse flow switch module 2 includes an MOS transistor, the gate of the MOS transistor needs to be triggered by a supply voltage, and the trigger output end of the current detection module 1 is connected to the trigger input end of the reverse flow switch module to supply power to the gate of the MOS transistor, so as to pull the voltage of the gate of the MOS transistor up to the voltage value of VCC.
More specifically, the current detection module 1 is connected to the first input end of the backflow switch module 2 through the first output end, and the second output end of the current detection module 1 is connected to the second input end of the backflow output module 2, so as to obtain voltage values at the two junctions, judge the current direction in the point charging circuit according to the obtained voltage values, and adjust the connection or disconnection of the MOS transistor in the backflow switch module 2 according to the forward direction and the reverse direction of the current.
The charging circuit may further include a filter module 3 and a voltage stabilizing protection module 4, and the filter module 3 and the voltage stabilizing protection module 4 are specifically described below:
the filtering module 3 is used for generating an alternating current shunt and filtering interference signals;
one end of the filtering module 3 is connected with the connection part of the direct current signal source VCC and the current detection module 1, and the other end is connected with the connection part of the power supply circuit V+ and the backflow switch module 2.
Regarding the filtering module 3: the filtering module 3 may comprise a capacitor, and the capacitor has the characteristic of passing alternating current and blocking direct current, and is connected in parallel between VCC and v+ to realize the effect of filtering interference signals.
The voltage stabilizing protection module 4 is used for ensuring that the voltage drop of the backflow switch module 2 is embedded to the breakdown voltage of the voltage stabilizing protection module 4, so that the circuit reliability is improved;
one end of the voltage stabilizing protection module 4 is connected with the connection part of the first input end and the trigger input end, and the other end of the voltage stabilizing protection module is connected with the connection part of the charging input end and the charging output end.
Regarding the voltage stabilizing protection module 4: the voltage stabilizing protection module 4 may include a voltage stabilizing device, which may be a voltage stabilizing tube, and the voltage stabilizing tube may be capable of embedding the voltage difference between the gate and the source in the reverse switch module 2 to the breakdown voltage corresponding to the voltage stabilizing tube, so as to ensure the reliability of the circuit.
In order to facilitate the above description, the voltage values at the two connection points are obtained, the current direction in the point charging circuit is determined according to the obtained voltage values, and the principle description of turning on or off the MOS transistor in the reverse flow switch module 2 is adjusted according to the forward direction and the reverse direction, please refer to fig. 3, fig. 3 is an equivalent schematic diagram of the anti-reverse flow circuit of the charging current provided in the embodiment of the present application, which is defined as a voltage point a and a voltage point B, and the following description is made:
in the above description, it is disclosed that the current detection module 1 includes a pull-up resistor and a closed triode, the reverse switch module 2 includes a MOS transistor, in fig. 3, R1 and R2 are used as pull-up resistors, the dc signal source VCC outputs a current I1 flowing through R1, and the current I1 can be divided into a current I2 outputted to the base of the triode Q and a current I3 flowing through the equivalent diode D, i.e. i1=i2+i3; in addition, since the NPN is composed of two back-to-back PN junctions and the reverse withstand voltage of Vbe is typically much lower than that of Vbc, the equivalent diode D is equivalent to the transistor Q1B in fig. 3 described below, and the voltage drop across D is denoted by Uak.
The resistor Rmos in fig. 3 refers to the resistance value of the MOS transistor in the reverse switch module 2 when turned on, and is equivalent to the resistor Rmos for convenience of description; the voltage difference between the collector c and the emitter e of the triode Q is Uce, the voltage difference between the base b and the emitter e is Ube, and parameters are set so that ube= Uak.
When the voltage value UA at the point A is equal to the voltage value UB at the point B: may be in a state in which the charger is not connected. In this case, since I2 and I3 are split by I1, and the sum of the voltages of ube=uak, ua=ub, UB and UA is equal to the sum of the voltages of Uak and UB, it can be colloquially understood that, in the total voltage, the larger the divided voltage, the larger the resistance of the resistor is, the larger the voltage on the route of the current I2 and the route of the current I3 is, the current I2 will be approximately equal to the current I3, at this time, the currents of I2 and I3 are not 0 and are approximately equal, the transistor Q is turned on, the between b and e of the transistor can be regarded as a path, and the Ube is approximately 0V.
When UA is greater than UB: the current direction from a to B, since i1=i2+i3 and ube=uak, UA > UB, the current I3 should be greater than I2, in which case the transistor Q starts to exit saturation, enter amplified state, until completely turned off, and finally I3 will be equal to I1, i2=0, the voltage across the transistors B and e is considered to be open, and the transistor Q is pulled up to VCC by R1.
When UA is less than UB: the current flows backward from B to a, and since i1=i2+i3 and ube=uak, UA < UB, the current I2 should be greater than I3, in which case transistor Q is on, the path between B and e of the transistor is considered as a path, ube is 0V, and I3 gradually decreases until i3=0, as in the principle that i3=i1 when UA is greater than UB.
As can be seen from the above description, when the current flows backward, the transistor Q is turned on, and the voltage at one end of Rmos is pulled up, so as to control the voltage difference between the gate of the MOS transistor and the source of the MOS transistor to be approximately 0, thereby turning off the MOS transistor and preventing the current from flowing backward.
Referring to fig. 4, fig. 4 is a schematic circuit diagram of a reverse current prevention circuit for charging current according to an embodiment of the present application, including a current detection module 1, a reverse current switch module 2, a filtering module 3, and a voltage stabilizing protection module 4;
the current detection module 1 comprises a first resistor R1, a second resistor R2, a third resistor R3, a first triode Q1A and a second triode Q1B;
one end of the first resistor R1 is connected with the direct current signal source VCC, the other end of the first resistor R1 is connected with the collector electrode of the first triode Q1A and one end of the second resistor R2, and the other end of the second resistor R2 is connected with the trigger input end of the reverse flow switch module 2;
the emitter of the first triode Q1A is connected with the first input end of the backflow switch module 2;
one end of the third resistor R3 is connected to the connection between the direct current signal source VCC and the first resistor R1, and the other end is connected to the emitter of the second triode Q1B, the base of the second triode Q1B, and the base of the first triode Q1A;
the collector electrode of the second triode Q1B is connected with the second input end of the backflow switch module 2;
the backflow switch module 2 comprises a MOS tube Q2;
the source electrode of the MOS tube Q2 is connected with the emitter electrode of the first triode Q1A and the power supply circuit V+, the grid electrode of the MOS tube is connected with the other end of the second resistor R2, and the drain electrode of the MOS tube Q2 is connected with the collector electrode of the second triode Q2B and the power load.
Specifically, the resistors R1 and R2 can pull up the trigger input terminal of the reverse switch module 2 to VCC, the resistor R2 can pull up the base and emitter of the MOS transistor Q1B to VCC, the two transistors Q1A and Q1B are sealed with a high symmetry of parameters, when no current flows in the reverse switch module 2, i.e. when no charging is performed, Q1A and Q1B form a balanced state, the Q1A and Q1B are slightly conducted, the gate potential of the MOS transistor Q2 is connected to the collector of Q1A through R2, the uoe of Q1A is approximately 0V, so that the gate voltage of the MOS transistor Q2 is less than the threshold of the turn-on voltage, which is typically 2V to 3V, and only slight current flows in the body diode of the MOS transistor Q2, which is negligible. As soon as a charging current flows in the reverse switching module 2, the equilibrium state is broken and an unbalanced state is entered, and only one transistor of Q1A and Q1B is turned on.
When the charging current is in a normal state, under the condition that the charging current is on, the Q1B is off, the grid electrode of the MOS tube in the reverse flow switch module 2 is pulled up to VCC by the R1 and the R2, the MOS tube Q2 is on, the current is normally output to an electricity load through the body diode of the MOS tube by the charger, and at the moment, the conduction voltage drop of the MOS tube is determined by the conduction resistance RDson of the MOS and the current product.
When the charging circuit is in a backward flowing state, under the condition that the Q1A is conducted, the Q1B is cut off, and in the backward flowing switch module 2, the grid potential of the MOS tube Q2 is connected to the collector of the Q1A through the R2, and as the Uce of the Q1A is 0V, the grid source voltage UGS of the MOS tube Q2 is close to 0V, the MOS tube Q2 can enter the cut-off state, the backward flowing current is stopped to be output to the power supply circuit V+, and the damage of a device for supplying power is avoided.
More specifically, when the dc signal source VCC and the power supply circuit v+ supply the dc signal to the anti-backflow circuit of the charging current of the present application, there may be an ac signal as an interference signal affecting the stability of the circuit operation, so the filtering module 3 is further added, and the following details of the filtering module 3 are described:
the filtering module 3 comprises a capacitor C1;
one end of the capacitor C1 is connected with the connection part of the direct current signal source VCC and the first resistor R1, and the other end of the capacitor C is connected with the connection part of the power supply circuit V+ and the MOS tube Q2.
Specifically, the capacitor C1 forms a bypass capacitor of the anti-backflow circuit through the connection mode, ensures the stability of signals input into the back-end circuit according to the characteristics of the capacitor, such as alternating current resistance and direct current resistance, and filters interference signals.
Further, in order to prevent the MOS transistor Q2 from being damaged due to an excessive signal transient or other conditions, the following description is made:
the voltage stabilizing protection module 4 comprises a voltage stabilizing tube ZD1;
the positive pole of the voltage stabilizing tube ZD1 is connected with the connection part of the first triode Q1A and the MOS tube Q2, and the negative pole of the voltage stabilizing tube ZD1 is connected with the connection part of the second resistor R2 and the MOS tube Q2.
Specifically, the positive electrode of the voltage stabilizing tube ZD1 is connected to the connection part of the emitter of the Q1A and the source electrode of the MOS tube Q2, the negative electrode is connected to the connection part of the resistor R2 and the grid electrode of the MOS tube Q2, the reverse breakdown voltage characteristic of the voltage stabilizing tube is utilized, the voltage between the grid electrode and the source electrode of the MOS tube Q2 is ensured to be embedded to the breakdown voltage of the voltage stabilizing tube, the devices are prevented from being damaged, and the reliability of the circuit is improved.
In another aspect of the present application, a method for preventing a charging current from flowing backward is disclosed, and the method is applied to a charging circuit, and includes:
controlling the charging circuit to be in a balance state, and judging whether charging current exists in the charging circuit or not;
if the charging current exists in the charging circuit, controlling the charging circuit to change from the balance state to the unbalance state;
if the charging circuit is in the unbalanced state, acquiring the current direction of the charging current;
and adjusting the internal conduction mode of the charging circuit according to the current direction, so as to control the conduction or disconnection of the charging circuit.
Specifically, the above-disclosed anti-backflow circuit for charging current is described, when no charging current is connected, a group of highly symmetrical sealing triodes in the current detection module 1 are turned on slightly at the same time, so that the charging circuit enters a balanced state, and once the balanced state is broken, one triode of the sealing triodes is necessarily turned on, the other triode is turned off, and the charging circuit is turned into an unbalanced state, so that the detection of the current direction is completed according to the conduction condition. Meanwhile, because of the conduction of the device, the conduction or disconnection of the MOS tube in the backflow switch module 2 is controlled, and when the current flows backwards, the MOS tube is controlled to be cut off.
In another aspect of the present application, a backflow preventing system for charging current is disclosed, including a current detecting module 100 and a backflow switching module 200, and the following details are described:
the current detection module 100 is configured to control the charging circuit to be in a balanced state, and determine whether a charging current exists in the charging circuit;
the current detection module 100 is further configured to control the charging circuit to change from the equilibrium state to the unbalanced state if the charging current exists in the charging circuit;
the current detection module 100 is further configured to obtain a current direction of the charging current if the charging circuit is in the unbalanced state;
and the reverse flow switch module 200 is used for adjusting the internal conduction mode of the charging circuit according to the current direction so as to control the conduction or disconnection of the charging circuit.
For specific limitations on the anti-backflow system of the charging current, reference may be made to the above limitation on the anti-backflow method of the charging current, and no further description is given here. The modules in the anti-backflow system for the charging current can be all or partially realized by software, hardware and a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in a computer device, or may be stored in software in a memory in the computer device, so that the embodiments of the present application are all preferred embodiments of the present application, and the protection scope of the present application is not limited by the embodiments of the present application, where the processor calls and executes operations corresponding to the above modules. All equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.
In another aspect of the present application, a device is provided, which carries a circuit structure of the anti-backflow circuit for charging current as described above.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus/network device and method may be implemented in other manners. For example, the apparatus/network device embodiments described above are merely illustrative, e.g., the division of modules or elements is merely a logical functional division, and there may be additional divisions when actually implemented, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (10)
1. A reverse current preventing circuit of charging current is characterized in that: the circuit comprises a current detection module and a backflow switch module;
the current detection module is used for detecting the current direction of the reverse flow switch module and changing the internal conduction mode of the current detection module according to the current direction;
the backflow switch module is used for adjusting the voltage drop of the backflow switch module according to the internal conduction mode of the current detection module so as to control the connection or disconnection of the backflow switch module;
the current detection module comprises an energy supply input end, a trigger output end, a first output end and a second output end, and the backflow switch module comprises a charging input end, a trigger input end, a first input end and a second input end;
the energy supply input end of the current detection module is connected with an external direct current signal source; the charging input end of the backflow switch module is connected with an external power supply circuit;
the trigger output end of the current detection module is connected with the trigger input end of the backflow switch module;
the first output end of the current detection module is connected with the first input end of the backflow switch module and is used for adjusting the internal voltage drop of the backflow switch module when the charging current flows backwards;
and the second output end of the current detection module is connected with the second input end of the backflow switch module and an external power load.
2. The anti-reverse current flowing circuit of claim 1, wherein: the circuit further comprises a filtering module;
the filtering module is used for generating an alternating current shunt and filtering interference signals;
one end of the filtering module is connected with the connection part of the direct current signal source and the current detection module, and the other end of the filtering module is connected with the connection part of the power supply circuit and the backflow switch module.
3. The anti-reverse current flowing circuit of claim 2, wherein: the circuit also comprises a voltage stabilizing protection module;
the voltage stabilizing protection module is used for ensuring that the voltage drop of the backflow switch module is embedded to the breakdown voltage of the voltage stabilizing protection module, so that the reliability of the circuit is improved;
one end of the voltage stabilizing protection module is connected with the connection part of the first input end and the trigger input end, and the other end of the voltage stabilizing protection module is connected with the connection part of the charging input end and the charging output end.
4. A charging current anti-reverse current circuit according to claim 3, wherein: the current detection module comprises a first resistor, a second resistor, a third resistor, a first triode and a second triode;
one end of the first resistor is connected with the direct current signal source, the other end of the first resistor is connected with the collector electrode of the first triode and one end of the second resistor, and the other end of the second resistor is connected with the trigger input end of the backflow switch module;
the emitter of the first triode is connected with the first input end of the backflow switch module;
one end of the third resistor is connected with the connection part of the direct current signal source and the first resistor, and the other end of the third resistor is connected with the emitter of the second triode, the base electrode of the second triode and the base electrode of the first triode;
and the collector electrode of the second triode is connected with the second input end of the backflow switch module.
5. The anti-reverse current flowing circuit of claim 4, wherein: the backflow switch module comprises an MOS tube;
the source electrode of the MOS tube is connected with the emitter electrode of the first triode and the power supply circuit, the grid electrode of the MOS tube is connected with the other end of the second resistor, and the drain electrode of the MOS tube is connected with the collector electrode of the second triode and the power load.
6. The anti-reverse current flowing circuit of claim 5, wherein: the filtering module comprises a capacitor;
one end of the capacitor is connected with the connection part of the direct current signal source and the first resistor, and the other end of the capacitor is connected with the connection part of the power supply circuit and the MOS tube.
7. The anti-reverse current flowing circuit of claim 6, wherein: the voltage stabilizing protection module comprises a voltage stabilizing tube;
the positive electrode of the voltage stabilizing tube is connected with the junction of the first triode and the MOS tube, and the negative electrode of the voltage stabilizing tube is connected with the junction of the second resistor and the MOS tube.
8. A method for preventing backflow of charging current, applied to a charging circuit, comprising:
controlling the charging circuit to be in a balance state, and judging whether charging current exists in the charging circuit or not;
if the charging current exists in the charging circuit, controlling the charging circuit to change from the balance state to the unbalance state;
if the charging circuit is in the unbalanced state, acquiring the current direction of the charging current;
and adjusting the internal conduction mode of the charging circuit according to the current direction, so as to control the conduction or disconnection of the charging circuit.
9. A backflow prevention system for charging current, comprising:
the current detection module is used for controlling the charging circuit to be in a balanced state and judging whether charging current exists in the charging circuit or not;
the current detection module is further configured to control the charging circuit to change from the equilibrium state to an unbalanced state if the charging current exists in the charging circuit;
the current detection module is further configured to obtain a current direction of the charging current if the charging circuit is in the unbalanced state;
and the reverse flow switch module is used for adjusting the internal conduction mode of the charging circuit according to the current direction so as to control the conduction or disconnection of the charging circuit.
10. An apparatus characterized by a circuit configuration carrying a reverse flow preventing circuit for charging current according to any one of claims 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311721883.0A CN117411149A (en) | 2023-12-14 | 2023-12-14 | Anti-backflow circuit, method, system and device for charging current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202311721883.0A CN117411149A (en) | 2023-12-14 | 2023-12-14 | Anti-backflow circuit, method, system and device for charging current |
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| CN117411149A true CN117411149A (en) | 2024-01-16 |
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| CN202311721883.0A Pending CN117411149A (en) | 2023-12-14 | 2023-12-14 | Anti-backflow circuit, method, system and device for charging current |
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| CN109167413A (en) * | 2018-10-11 | 2019-01-08 | 佛山职业技术学院 | A kind of anti-reverse and anti-back flow circuit of battery charging |
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|---|---|---|---|---|
| CN1297613A (en) * | 1998-04-14 | 2001-05-30 | Nmb(美国)公司 | Circuit simulating diode |
| US20060208653A1 (en) * | 2003-03-07 | 2006-09-21 | Integrated Electronic Solutions Pty Ltd | Circuit improvements for solar lamps |
| CN101490922A (en) * | 2006-07-27 | 2009-07-22 | 雅迪信科技有限公司 | Improved controller for o-ring field effect transistor |
| CN106300321A (en) * | 2016-08-31 | 2017-01-04 | 四川升华电源科技有限公司 | Power supply anti-back flow circuit |
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