CN109698538B - Battery charging circuit and battery charging method - Google Patents
Battery charging circuit and battery charging method Download PDFInfo
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- CN109698538B CN109698538B CN201910139105.8A CN201910139105A CN109698538B CN 109698538 B CN109698538 B CN 109698538B CN 201910139105 A CN201910139105 A CN 201910139105A CN 109698538 B CN109698538 B CN 109698538B
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- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000001514 detection method Methods 0.000 claims description 88
- 239000003990 capacitor Substances 0.000 claims description 29
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 7
- 229910052744 lithium Inorganic materials 0.000 claims description 7
- 229910044991 metal oxide Inorganic materials 0.000 claims description 2
- 150000004706 metal oxides Chemical class 0.000 claims description 2
- 239000004065 semiconductor Substances 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 9
- 230000006870 function Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- OJIJEKBXJYRIBZ-UHFFFAOYSA-N cadmium nickel Chemical compound [Ni].[Cd] OJIJEKBXJYRIBZ-UHFFFAOYSA-N 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- H02J7/0077—
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- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention relates to the field of charging circuits, in particular to a battery charging circuit and a battery charging method; the battery charging circuit comprises a positive input end, a negative input end, a MOS tube Q1, a controller and a battery; the MOS transistor Q1 is connected in series between the positive input end and the positive electrode of the battery. According to the battery charging circuit and the battery charging method, the MOS tube is used for replacing a diode in the existing charging circuit, so that the conduction voltage drop in the circuit can be greatly reduced, the charging current and the charging efficiency are improved, and the temperature rise and the reliability of the whole circuit are improved; and through a specific battery charging method, whether the adapter is normally connected or not can be judged in the charging process, the possible problems in the charging process are solved, and the charging process is ensured to be stably and reliably carried out.
Description
Technical Field
The present invention relates to the field of charging circuits, and in particular, to a battery charging circuit and a battery charging method.
Background
The existing battery (such as nickel-hydrogen, nickel-cadmium and lithium battery) products are more and more popular, because these battery devices need to be charged, so the input ends are always isolated by using diodes, one function is to prevent the charger from connecting reversely to burn out the whole circuit at the rear end, and the other function is to isolate the reverse voltage of the battery at the rear end, thereby reliably judging whether the charger is inserted. However, the conduction voltage drop of the diode is large, and with the rise of current, the voltage drop will further rise according to the volt-ampere characteristic curve of the diode, and the current loss is large and the heat is serious; in the field of quick charging of batteries, the application of diodes greatly limits the increase of charging current.
Disclosure of Invention
In order to solve the above mentioned deficiencies in the prior art, the present invention provides a battery charging circuit and a battery charging method, so as to improve the charging efficiency of the battery;
in order to achieve the above object, the present invention provides a battery charging circuit, which includes a positive input terminal, a negative input terminal, a MOS transistor Q1, a controller and a battery; the MOS tube Q1 is connected in series between the positive input end and the positive electrode of the battery, and the MOS tube Q1 is controlled by the controller;
an input voltage detection circuit and an adapter forward access detection circuit are also arranged between the positive input end and the negative input end; the input voltage detection circuit is used for detecting the voltage between the positive input end and the negative input end and feeding back the voltage to the controller;
the adapter forward access detection circuit comprises a resistor R13, a resistor R15 and a triode T1; the triode T1 is an NPN type triode; the resistor R13 and the resistor R15 are connected in series and then are connected in series between the positive input end and the negative input end; the base electrode of the triode T1 is connected to the common end of the resistor R13 and the resistor R15, the emitter electrode of the triode T1 is connected to the negative input end, the collector electrode of the triode T1 is the forward access detection end of the adapter, and the controller is connected with the forward access detection end of the adapter.
Further, the input voltage detection circuit comprises a resistor R7, a resistor R8, a resistor R1 and a capacitor C1, wherein the resistor R7 and the resistor R8 are connected in series and then connected in series between the positive input end and the negative input end; one end of the resistor R1 is connected to the common end of the resistor R7 and the resistor R8, and the other end of the resistor R1 is connected to the negative input end through a capacitor C1; the common end of the resistor R1 and the capacitor C1 is an input voltage detection end, and the controller is connected with the input voltage detection end.
Further, the controller controls the operation of the MOS tube Q1 through the MOS tube Q1 driving circuit; the MOS transistor Q1 driving circuit comprises a resistor R11, a resistor R16, a resistor R17 and a triode T2; one end of the resistor R17 is connected to the collector of the triode T2, the other end of the resistor R17 is divided into two paths, one path is connected to the gate of the MOS transistor Q1, and the other path is connected to the source of the MOS transistor Q1 through a resistor R11; the base of the transistor T2 is connected to the controller through a resistor R16, and the emitter of the transistor T2 is connected to the negative input terminal.
Further, the charging current control circuit is further included, and the charging current control circuit includes a MOS transistor Q2, a transistor T3, and a transistor T4; the MOS transistor Q2 is connected in series between the source electrode of the MOS transistor Q1 and the anode of the battery, wherein the drain electrode of the MOS transistor Q2 is connected with the anode of the battery; the base electrodes of the triode T3 and the triode T4 are connected with the controller; the emitting electrodes of the triode T3 and the triode T4 are connected with the grid electrode of the MOS tube through a resistor R22; the collector of the triode T3 is connected with the source of the MOS transistor Q1; the collector of the transistor T4 is connected to the negative input terminal.
Further, the charging current detection circuit is further included, and comprises a resistor R26, a resistor R27, a resistor R2, a resistor R3, a capacitor C3 and a capacitor C4; the resistor R26 and the resistor R27 are connected in parallel and then connected in series between the drain of the MOS transistor Q2 and the anode of the battery; one end of the resistor R26 and the resistor R27 which are connected in parallel is connected to the negative input end through a resistor R2 and a capacitor C3; the other end of the resistor R26 and the resistor R27 which are connected in parallel is connected to the negative input end through a resistor R3 and a capacitor C4; the common end of the resistor R3 and the capacitor C4, and the common end of the resistor R2 and the capacitor C3 are respectively a first voltage detection end and a second voltage detection end.
Further, the device also comprises a battery protection loop; the battery protection loop comprises a lithium battery protection chip, an MOS tube Q4 and an MOS tube Q5; the lithium battery protection chip is S-8261 in model number.
The invention also provides a battery charging method applied to the battery charging circuit, which comprises the following steps:
s100: detecting a level signal of a forward access detection end through a controller, if the level signal is low level, judging that the adapter is in forward access, and controlling the conduction of an MOS (metal oxide semiconductor) tube Q1 to charge a battery; if the adapter is in a high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery charging is stopped;
s200: during the charging period of the battery, the MOS tube Q1 is controlled to be cut off for 4ms every 200ms, then the level signal of the forward access detection end is detected by the controller, if the level signal is low, the adapter is judged to be accessed in the forward direction, the MOS tube Q1 is controlled to be switched on, and the battery is continuously charged; if the adapter is in a high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery charging is stopped;
s300: during the charging of the battery, when the voltage between the positive input end and the negative input end detected by the controller through the input voltage detection circuit is smaller than a set threshold value, the MOS tube Q1 is controlled to be cut off for 400ms, then the controller detects a level signal of a positive access detection end, if the level signal is low, the adapter is judged to be accessed in the positive direction, the MOS tube Q1 is controlled to be switched on, and the battery is continuously charged; if the adapter is in the high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery charging is stopped.
Further, the method further comprises the step S400: during the charging of the battery, when the charging current detected by the current detection circuit is smaller than a set threshold value, the MOS transistor Q1 is controlled to be cut off for 400ms, then a level signal of a forward access detection end is detected by the controller, if the level signal is low, the adapter is judged to be in forward access, and the MOS transistor Q1 is controlled to be switched on; if the state is the high-impedance state, the adapter is judged to be reversely connected, and the MOS tube Q1 is controlled to be cut off.
According to the battery charging circuit and the battery charging method, the MOS tube is used for replacing a diode in the existing charging circuit, so that the conduction voltage drop in the circuit can be greatly reduced, the charging current and the charging efficiency are improved, and the temperature rise and the reliability of the whole circuit are improved; and through a specific battery charging method, whether the adapter is normally connected or not can be judged in the charging process, the possible problems in the charging process are solved, and the charging process is ensured to be stably and reliably carried out.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of a battery charging circuit according to the present invention.
Reference numerals:
| 10 positive input end | 20 |
30 |
| 40 cell |
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.
The use of "first," "second," and similar language in the embodiments of the present invention does not denote any order, quantity, or importance, but rather the terms "first," "second," and similar language are used to distinguish one element from another. "one end," "the other end," and the like are used solely to indicate that a device or element is oriented or positioned in a particular manner based on the orientation or position illustrated in the drawings and are not intended to indicate or imply that the device or element so referred to must have the particular orientation, be constructed and operated in the particular manner. The word "comprising" or "comprises", and the like, means that the element or item preceding the word covers the element or item listed after the word and its equivalents, but not the other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect.
The invention provides a battery charging circuit, which comprises a positive input end 10, a negative input end 20, an MOS tube Q1, a controller 30 and a battery 40; the MOS transistor Q1 is connected in series between the positive input terminal 10 and the positive electrode of the battery 40, and the MOS transistor Q1 is controlled by the controller 30;
an input voltage detection circuit and an adapter forward access detection circuit are also arranged between the positive input end 10 and the negative input end 20; the input voltage detection circuit is configured to detect a voltage between the positive input terminal 10 and the negative input terminal 20 and feed back the voltage to the controller 30;
the adapter forward access detection circuit comprises a resistor R13, a resistor R15 and a triode T1; the triode T1 is an NPN type triode; the resistor R13 and the resistor R15 are connected in series and then connected in series between the positive input end 10 and the negative input end 20; the base of the transistor T1 is connected to the common terminal of the resistor R13 and the resistor R15, the emitter of the transistor T1 is connected to the negative input terminal 20, the collector of the transistor T1 is the forward connection detection terminal of the adapter, and the controller 30 is connected to the forward connection detection terminal of the adapter.
In specific implementation, a positive input end 10 and a negative input end 20 of the battery charging circuit provided in the embodiment of the present invention are respectively used for connecting two output ends of an adapter, where the positive input end 10 is used for connecting a positive output end of the adapter, and the negative input end 20 is used for connecting a negative output end of the adapter; as shown in fig. 1, a MOS transistor Q1 is disposed between the positive input terminal 10 and the positive electrode of the battery 40, and the MOS transistor Q1 is a P-channel MOS transistor; the drain of the MOS transistor Q1 is connected to the positive input terminal 10, and the source of the MOS transistor Q1 is connected to the positive terminal of the battery 40; the MOS tube Q1 is controlled by the controller 30 to be switched on or switched off, in the embodiment of the invention, the controller is a singlechip, and the model of the controller is HT66F0185-28 SSOP.
Specifically, the controller 30 controls the MOS transistor Q1 to operate through the MOS transistor Q1 driving circuit; the MOS transistor Q1 driving circuit comprises a resistor R11, a resistor R16, a resistor R17 and a triode T2; one end of the resistor R17 is connected to the collector of the triode T2, the other end of the resistor R17 is divided into two paths, one path is connected to the grid of the MOS transistor Q1, and the other path is connected to the source of the MOS transistor Q1 through the resistor R11; the base of the transistor T2 is connected to the controller 30 through a resistor R16, and the emitter of the transistor T2 is connected to the negative input terminal 20. The triode T2 is an NPN type triode, and when the controller 30 outputs a high level signal to the base of the triode T2, the triode T2 is turned on, and the gate voltage of the MOS transistor Q1 is pulled down to a low level, so that the MOS transistor Q1 is turned on; when the controller 30 outputs a low level signal to the base of the transistor T2, the transistor T2 is turned off, and the gate voltage of the MOS transistor Q1 is restored to a high level, so that the MOS transistor Q1 is turned off.
As shown in fig. 1, an input voltage detection circuit is further disposed between the positive input terminal 10 and the negative input terminal 20, the input voltage detection circuit includes a resistor R7, a resistor R8, a resistor R1, and a capacitor C1, and the resistor R7 and the resistor R8 are connected in series and then connected in series between the positive input terminal 10 and the negative input terminal 20; one end of the resistor R1 is connected to the common end of the resistor R7 and the resistor R8, and the other end of the resistor R1 is connected to the negative input terminal 20 through the capacitor C1; a common end of the resistor R1 and the capacitor C1 is an input voltage detection end (such as a node Vcharg shown in fig. 1), and the controller 30 is connected to the input voltage detection end; wherein the resistance values of the resistor R7 and the resistor R8 are both preferably 10k omega; when there is an input voltage between the positive input terminal 10 and the negative input terminal 20, a voltage value, which is one-half of the input voltage between the positive input terminal 10 and the negative input terminal 20, can be detected at a common terminal of the resistor R7 and the resistor R8, i.e., an input voltage detection terminal, by the voltage division action of the resistor R7 and the resistor R8, and the controller 30 can obtain the input voltage between the positive input terminal 10 and the negative input terminal 20 by detecting the voltage at the input voltage detection terminal.
As shown in fig. 1, an adapter forward access detection circuit is further disposed between the positive input end 10 and the negative input end 20, and includes a resistor R13, a resistor R15, and a transistor T1; the triode T1 is an NPN type triode; the resistor R13 and the resistor R15 are connected in series and then are connected in series between the positive input end 10 and the negative input end 20; the base of the transistor T1 is connected to the common terminal of the resistor R13 and the resistor R15, the emitter of the transistor T1 is connected to the negative input terminal 20, the collector of the transistor T1 is the forward connection detection terminal of the adapter (node CHARG shown in fig. 1), and the controller 30 is connected to the forward connection detection terminal of the adapter. In actual operation, when the adapter is accessed in the positive direction, i.e. the positive input terminal 10 is connected to the positive output terminal of the adapter, and the negative input terminal 20 is connected to the negative output terminal of the adapter; at this time, the base voltage of the transistor T1 will be higher than the emitter voltage thereof, the transistor T1 will be turned on, so that the collector of the transistor T1 is conducted to the negative input terminal 20, and the adapter positive-going access detection terminal will detect a low level; when the adapter is switched in the reverse direction, namely the positive input end 10 is connected to the positive output end of the adapter, and the negative input end 20 is connected to the negative output end of the adapter; at this time, the base voltage of the transistor T1 will be lower than the emitter voltage thereof, and the transistor T1 will be turned on, so that the collector of the transistor T1 is conducted to the negative input terminal 20, and the adapter positive connection detection terminal will detect the high impedance state.
As shown in fig. 1, the charging circuit further includes a charging current control circuit, where the charging current control circuit includes a MOS transistor Q2, a transistor T3, and a transistor T4; the MOS transistor Q2 is connected in series between the source of the MOS transistor Q1 and the positive electrode of the battery 40, wherein the drain of the MOS transistor Q2 is connected to the positive electrode of the battery 40; the bases of the triode T3 and the triode T4 are connected with the controller 30; the emitting electrodes of the triode T3 and the triode T4 are connected with the grid electrode of the MOS tube through a resistor R22; the collector of the triode T3 is connected with the source of the MOS transistor Q1; the collector of the transistor T4 is connected to the negative input terminal 20. In actual operation, the controller 30 outputs PWM signals to the transistor T3 and the transistor T4, and controls the ratio of the on time and the off time of the MOS transistor Q2 per unit time, thereby controlling the magnitude of the charging current.
Preferably, the charging circuit further comprises a charging current detection circuit, wherein the charging current detection circuit comprises a resistor R26, a resistor R27, a resistor R2, a resistor R3, a capacitor C3 and a capacitor C4; the resistor R26 and the resistor R27 are connected in parallel and then connected in series between the drain of the MOS transistor Q2 and the positive electrode of the battery 40; one end of the resistor R26 and the resistor R27 which are connected in parallel is connected to the negative input end 20 through a resistor R2 and a capacitor C3; the other end of the resistor R26 and the resistor R27 which are connected in parallel is connected to the negative input end 20 through a resistor R3 and a capacitor C4; the common terminal of the resistor R3 and the capacitor C4 is a first voltage detection terminal (shown as a node VBAT1 in fig. 1), a common terminal of the resistor R2 and the capacitor C3, and a second voltage detection terminal (shown as a node VBAT2 in fig. 1). In actual operation, the magnitude of the passing current, i.e., the magnitude of the charging current, can be calculated according to the resistance values of the resistor R26 and the resistor R27 by calculating the voltage difference between the first voltage detection terminal and the second voltage detection terminal, i.e., the voltage drop between the resistor R26 and the resistor R27.
Preferably, a battery 40 protection circuit is also included; the battery 40 protection loop comprises a lithium battery 40 protection chip, an MOS tube Q4 and an MOS tube Q5; the lithium battery 40 protective chip is of the type S-8261.
The invention also provides a battery charging method applied to the battery charging circuit, which comprises the following steps:
s100: detecting a level signal of a forward access detection end through the controller 30, if the level signal is low level, judging that the adapter is accessed in the forward direction, and controlling the conduction of the MOS tube Q1 to charge the battery 40; if the adapter is in the high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery 40 is stopped to be charged;
specifically, as shown in fig. 1, an adapter forward access detection circuit is provided between the positive input terminal 10 and the negative input terminal 20, and a level signal of the forward access detection terminal in the adapter forward access detection circuit is detected by the controller 30; if the detected level signal of the forward access detection end is low level, the adapter is determined to be in forward access, that is, the positive input end 10 is connected to the positive output end of the adapter, the negative input end 20 is connected to the negative output end of the adapter, and at this time, the MOS transistor Q1 is controlled to be turned on by the controller 30 to charge the battery 40; if the detected level signal of the forward access detection terminal is in a high impedance state, it is determined that the adapter is abnormally accessed, for example, reversely accessed or not accessed, and at this time, the MOS transistor Q1 is controlled to be turned off by the controller 30, and the battery 40 is stopped being charged.
S200: during the charging period of the battery 40, the MOS tube Q1 is controlled to be cut off for 4ms every 200ms, then the level signal of the forward access detection end is detected by the controller 30, if the level signal is low, the adapter is judged to be in forward access, the MOS tube Q1 is controlled to be connected, and the battery 40 is continuously charged; if the adapter is in the high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery 40 is stopped to be charged;
s300: during the charging of the battery 40, when the voltage between the positive input terminal 10 and the negative input terminal 20 detected by the controller 30 through the input voltage detection circuit is smaller than a set threshold, the MOS transistor Q1 is controlled to be cut off for 400ms, then the level signal of the positive access detection terminal is detected through the controller 30, if the level signal is low, the adapter is determined to be accessed in the positive direction, the MOS transistor Q1 is controlled to be switched on, and the battery 40 is continuously charged; if the state is high impedance, it is determined that the adapter is not normally connected, and the MOS transistor Q1 is controlled to be turned off, thereby stopping charging the battery 40.
Specifically, during the period when it is determined in step S100 that the adaptor is connected in the forward direction to charge the battery 40, the MOS transistor Q1 is controlled to be cut off for 4ms every 200ms, the connection between the positive electrode of the battery 40 and the transistor T1 is disconnected, then the level signal of the forward access detection terminal is detected by the controller 30, and if the detected level signal of the forward access detection terminal is low level, the adaptor is determined to be connected in the forward direction, the MOS transistor Q1 is controlled to be turned on, and the battery 40 is continuously charged; if the detected level signal of the forward access detection end is in a high impedance state, the adapter is judged to be accessed in a reverse direction or not, the MOS tube Q1 is controlled to be cut off, and the battery 40 is stopped to be charged.
If the voltage between the positive input terminal 10 and the negative input terminal 20 detected by the controller 30 through the input voltage detection circuit during the charging of the battery 40 is smaller than a set threshold value, and the threshold value is smaller than the voltage between the positive input terminal 10 and the negative input terminal 20 when the adapter normally works (i.e. the output voltage of the adapter is preferably four fifths of the normal output voltage of the adapter), the controller 30 controls the MOS transistor Q1 to be cut off for 400ms, then the controller 30 detects a level signal of the forward access detection terminal, and if the detected level signal of the forward access detection terminal is a low level, the adapter is determined to be in the forward access, the MOS transistor Q1 is controlled to be turned on, and the battery 40 is continuously charged; if the detected level signal of the forward access detection end is in a high impedance state, the adapter is judged to be abnormally accessed, and the MOS tube Q1 is controlled to be cut off, so that the battery 40 is stopped being charged.
Because of the conduction of the MOS transistor Q1, if the connection between the adapter and the battery charging circuit is disconnected at this time, the voltage of the battery 40 can be reversely poured back to the base of the triode T1 through the parasitic diode of the MOS transistor Q2 and the MOS transistor Q1, so as to continue to drive the conduction of the triode T1, the level signal of the forward access detection end detected by the controller 30 is still at a low level, and the controller 30 is difficult to effectively judge whether the adapter is disconnected from the battery charging circuit; and every 200ms controls the MOS transistor Q1 to cut off for 4ms, which enables the equivalent capacitor between the positive input terminal 10 and the negative input terminal 20 to effectively discharge, improves the accuracy of the forward access detection of the adapter, and simultaneously does not affect the overall charging current, thereby ensuring the charging of the battery 40.
When the current input of the adapter is disconnected, but the adapter is not disconnected from the battery charging circuit, since the adapter is connected to the battery charging circuit, the equivalent capacitance between the positive input terminal 10 and the negative input terminal 20 will be greatly increased, at which time the control MOS transistor Q1 is turned off for 4ms, the equivalent capacitor cannot be effectively discharged, it is difficult for the controller 30 to effectively determine whether the adapter is removed, however, since the output voltage of the adapter is greater than the output voltage of the battery 40, a threshold value may be preset, when the voltage between the positive input terminal 10 and the negative input terminal 20 detected by the controller 30 through the input voltage detection circuit is smaller than the set threshold value, by controlling the MOS tube Q1 to cut off for 400ms, the equivalent capacitance between the positive input end 10 and the negative input end 20 can be discharged, and the detection of the forward access of the adapter is carried out at the moment, so that the accuracy of the detection of the forward access of the adapter can be improved.
Preferably, the method further comprises the step S400: during the charging of the battery 40, when the charging current detected by the current detection circuit is smaller than a set threshold value, the MOS transistor Q1 is controlled to be cut off for 400ms, then the level signal of the forward access detection end is detected by the controller 30, if the level signal is low, the adapter is determined to be in forward access, and the MOS transistor Q1 is controlled to be switched on; if the state is the high-impedance state, the adapter is judged to be reversely connected, and the MOS tube Q1 is controlled to be cut off.
Specifically, during the charging of the battery 40, the charging current may be monitored in real time by the current detection circuit, when the charging current detected by the current detection circuit is smaller than a set threshold, the controller 30 controls the MOS transistor Q1 to be turned off for 400ms, then the controller 30 detects a level signal of the forward access detection terminal, and if the detected level signal of the forward access detection terminal is a low level, it is determined that the adapter is in forward access, and the MOS transistor Q1 is controlled to be turned on, so as to continue to charge the battery 40; if the detected level signal of the forward access detection end is in a high impedance state, the adapter is judged to be abnormally accessed, and the MOS tube Q1 is controlled to be cut off, so that the battery 40 is stopped being charged.
According to the battery charging circuit and the battery charging method provided by the embodiment of the invention, the MOS tube is adopted to replace a diode in the existing charging circuit, so that the conduction voltage drop in the circuit can be greatly reduced, the charging current and the charging efficiency are improved, and the temperature rise and the reliability of the whole circuit are improved; and through a specific battery charging method, whether the adapter is normally connected or not can be judged in the charging process, the possible problems in the charging process are solved, and the charging process is ensured to be stably and reliably carried out.
Although terms such as MOS transistors, input terminals, detection terminals, adapters, etc. are used more often herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. A battery charging circuit, characterized by: the device comprises a positive input end, a negative input end, an MOS tube Q1, a controller and a battery; the MOS tube Q1 is connected in series between the positive input end and the positive electrode of the battery, and the MOS tube Q1 is controlled by the controller through a driving circuit;
an input voltage detection circuit and an adapter forward access detection circuit are also arranged between the positive input end and the negative input end; the input voltage detection circuit is used for detecting the voltage between the positive input end and the negative input end and feeding back the voltage to the controller;
the adapter forward access detection circuit comprises a resistor R13, a resistor R15 and a triode T1; the triode T1 is an NPN type triode; the resistor R13 and the resistor R15 are connected in series and then are connected in series between the positive input end and the negative input end; the base electrode of the triode T1 is connected to the common end of the resistor R13 and the resistor R15, the emitter electrode of the triode T1 is connected to the negative input end, the collector electrode of the triode T1 is the forward access detection end of the adapter, and the controller is connected with the forward access detection end of the adapter.
2. A battery charging circuit as claimed in claim 1, wherein: the input voltage detection circuit comprises a resistor R7, a resistor R8, a resistor R1 and a capacitor C1, wherein the resistor R7 and the resistor R8 are connected in series and then connected in series between the positive input end and the negative input end; one end of the resistor R1 is connected to the common end of the resistor R7 and the resistor R8, and the other end of the resistor R1 is connected to the negative input end through a capacitor C1; the common end of the resistor R1 and the capacitor C1 is an input voltage detection end, and the controller is connected with the input voltage detection end.
3. A battery charging circuit as claimed in claim 1, wherein: the controller controls the MOS tube Q1 to work through an MOS tube Q1 driving circuit; the MOS transistor Q1 driving circuit comprises a resistor R11, a resistor R16, a resistor R17 and a triode T2; one end of the resistor R17 is connected to the collector of the triode T2, the other end of the resistor R17 is divided into two paths, one path is connected to the gate of the MOS transistor Q1, and the other path is connected to the source of the MOS transistor Q1 through a resistor R11; the base of the transistor T2 is connected to the controller through a resistor R16, and the emitter of the transistor T2 is connected to the negative input terminal.
4. A battery charging circuit as claimed in claim 1, wherein: the charging circuit comprises a MOS tube Q2, a triode T3 and a triode T4; the MOS transistor Q2 is connected in series between the source electrode of the MOS transistor Q1 and the anode of the battery, wherein the drain electrode of the MOS transistor Q2 is connected with the anode of the battery; the base electrodes of the triode T3 and the triode T4 are connected with the controller; the emitting electrodes of the triode T3 and the triode T4 are connected with the grid electrode of the MOS tube through a resistor R22; the collector of the triode T3 is connected with the source of the MOS transistor Q1; the collector of the transistor T4 is connected to the negative input terminal.
5. A battery charging circuit as claimed in claim 1, wherein: the charging current detection circuit comprises a resistor R26, a resistor R27, a resistor R2, a resistor R3, a capacitor C3 and a capacitor C4; the resistor R26 and the resistor R27 are connected in parallel and then connected in series between the drain of the MOS transistor Q2 and the anode of the battery; one end of the resistor R26 and the resistor R27 which are connected in parallel is connected to the negative input end through a resistor R2 and a capacitor C3; the other end of the resistor R26 and the resistor R27 which are connected in parallel is connected to the negative input end through a resistor R3 and a capacitor C4; the common end of the resistor R3 and the capacitor C4, and the common end of the resistor R2 and the capacitor C3 are respectively a first voltage detection end and a second voltage detection end.
6. A battery charging circuit as claimed in claim 1, wherein: the battery protection circuit is also included; the battery protection loop comprises a lithium battery protection chip, an MOS tube Q4 and an MOS tube Q5; the lithium battery protection chip is S-8261 in model number.
7. A battery charging method applied to a battery charging circuit according to any one of claims 1 to 6, characterized in that: the method comprises the following steps:
s100: detecting a level signal of a forward access detection end through a controller, if the level signal is low level, judging that the adapter is in forward access, and controlling the conduction of an MOS (metal oxide semiconductor) tube Q1 to charge a battery; if the adapter is in a high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery charging is stopped;
s200: during the charging period of the battery, the MOS tube Q1 is controlled to be cut off for 4ms every 200ms, then the level signal of the forward access detection end is detected by the controller, if the level signal is low, the adapter is judged to be accessed in the forward direction, the MOS tube Q1 is controlled to be switched on, and the battery is continuously charged; if the adapter is in a high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery charging is stopped;
s300: during the charging of the battery, when the voltage between the positive input end and the negative input end detected by the controller through the input voltage detection circuit is smaller than a set threshold value, the MOS tube Q1 is controlled to be cut off for 400ms, then the controller detects a level signal of a positive access detection end, if the level signal is low, the adapter is judged to be accessed in the positive direction, the MOS tube Q1 is controlled to be switched on, and the battery is continuously charged; if the adapter is in the high-impedance state, the adapter is judged to be abnormally connected, the MOS tube Q1 is controlled to be cut off, and the battery charging is stopped.
8. A battery charging method according to claim 7, wherein: further comprising step S400: during the charging of the battery, when the charging current detected by the current detection circuit is smaller than a set threshold value, the MOS transistor Q1 is controlled to be cut off for 400ms, then a level signal of a forward access detection end is detected by the controller, if the level signal is low, the adapter is judged to be in forward access, and the MOS transistor Q1 is controlled to be switched on; if the state is the high-impedance state, the adapter is judged to be reversely connected, and the MOS tube Q1 is controlled to be cut off.
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| CN114384843B (en) * | 2021-12-31 | 2024-03-29 | 厦门芯阳科技股份有限公司 | Circuit with wake-up and detection functions and electronic equipment |
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| CN103094937A (en) * | 2011-10-31 | 2013-05-08 | 海洋王照明科技股份有限公司 | Intelligent charging circuit and lamp |
| CN104218539A (en) * | 2013-05-29 | 2014-12-17 | 惠州市吉瑞科技有限公司 | Charging circuit and charging method capable of preventing reverse connection of rechargeable power supply |
| CN206452153U (en) * | 2017-02-14 | 2017-08-29 | 深圳市维创尼克科技有限公司 | A kind of reverse-filling ideal diode of use chip microcontroller |
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