CN112366780A - Average current constant type charging device and method - Google Patents
Average current constant type charging device and method Download PDFInfo
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- CN112366780A CN112366780A CN202011247859.4A CN202011247859A CN112366780A CN 112366780 A CN112366780 A CN 112366780A CN 202011247859 A CN202011247859 A CN 202011247859A CN 112366780 A CN112366780 A CN 112366780A
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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
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
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Abstract
The invention provides an average current constant type charging device and method, comprising a switching circuit, a voltage sampling detection circuit and a duty ratio regulation circuit; the input end of the switch circuit is connected with a charging output port, the output end of the switch circuit is connected with a lithium battery, and the input end of the voltage sampling detection circuit is respectively connected with the switch circuit and the lithium battery; the output end of the voltage sampling detection circuit is connected with the duty cycle adjusting circuit, and the output end of the duty cycle adjusting circuit is connected with the switching circuit; the duty ratio adjusting circuit controls the on and off of the switch circuit according to the voltage difference detected by the voltage sampling detection circuit, and further controls the average charging current. The voltage difference at two ends of the switch circuit is detected through the voltage sampling detection circuit, the duty ratio is adjusted by controlling the state of the switch circuit through the duty ratio adjusting circuit, and then the average current is controlled to be in a constant state.
Description
Technical Field
The invention relates to the technical field of motors, in particular to an average current constant type charging device and method capable of keeping average current constant.
Background
In recent years, rechargeable lithium batteries are widely used, and most of portable equipment such as fans, solar lamps, electric toothbrushes, hair clippers and the like are powered by the rechargeable lithium batteries. There are two main principles responsible for this trend: firstly, the modern life concept attaches more and more importance to environmental protection, and compared with a disposable battery, the rechargeable lithium battery has smaller burden on the environment; secondly, the lithium battery technology is obviously advanced, and especially, the lithium battery makes a breakthrough in the aspects of charging time, safety performance and the like.
The rechargeable lithium battery is charged by mainly adopting the following charging modes: the first method is as follows: and a diode is adopted for charging. Directly connecting a charger or a solar photovoltaic panel with a diode to directly charge a battery; in this way, the charging current is not constant, the current is not controllable, and the current has a great relation with the voltage of the charging device and the battery and has a great change. The second method comprises the following steps: and charging by adopting a linear voltage stabilizing circuit. For example, 4056 charging chips are adopted, but the current in the method is small and generally does not exceed 1 ampere, and when the capacity of the battery is large, the method is not applicable and the charging is slow. The third method comprises the following steps: and a switching power supply circuit is adopted for charging. There are buck-type or boost-type chips for charge control, which is costly, and the charging current has a large relationship with the charging device and the battery voltage, making the use inflexible.
For lithium batteries, the significance of keeping the average current constant in the charging process is important, and the prior art is difficult to realize the average current constant through low cost, which is a bottleneck to be broken in the industry.
Disclosure of Invention
The present invention is directed to provide a constant average current charging apparatus and method, which can achieve constant average current with a simple circuit structure and at a low cost.
The technical scheme adopted by the invention for solving the technical problem is as follows:
an average current constant type charging device comprises a switching circuit, a voltage sampling detection circuit and a duty ratio regulation circuit;
the input end of the switch circuit is connected with the charging output port, the output end of the switch circuit is connected with the lithium battery, and the input end of the voltage sampling detection circuit is respectively connected with the switch circuit and the lithium battery; the output end of the voltage sampling detection circuit is connected with the duty cycle adjusting circuit, and the output end of the duty cycle adjusting circuit is connected with the switching circuit;
the voltage sampling detection circuit is used for collecting the voltage difference between the input end and the output end of the switch circuit;
the duty ratio adjusting circuit is used for controlling the on and off of the switch circuit according to the voltage difference detected by the voltage sampling detection circuit, and further controlling the average charging current of the lithium battery.
Compared with the prior art, the technical scheme has the beneficial effects that: the charging current of the lithium battery is not required to be additionally detected, the voltage difference at two ends of the switch circuit is only required to be detected through the voltage sampling detection circuit, the duty ratio is adjusted by controlling the state of the switch circuit through the duty ratio adjusting circuit, and then the average current is controlled to be in a constant state.
Further, the switch circuit comprises a PMOS tube;
the grid electrode of the PMOS tube is connected with the duty ratio adjusting circuit, the source electrode of the PMOS tube is connected with the charging output port, and the drain electrode of the PMOS tube is connected with the lithium battery.
The beneficial effect who adopts above-mentioned scheme is: the PMOS tube is connected with the duty ratio adjusting circuit through the grid electrode of the PMOS tube, the duty ratio adjusting circuit can control the state of the PMOS tube only by controlling the level output to the grid electrode of the PMOS tube, and the basic function of the switch circuit is realized through a simple circuit structure.
Further, the voltage sampling detection circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
one end of the first resistor is connected with the input end of the switch circuit, and the other end of the first resistor is grounded through the second resistor;
one end of the third resistor is connected with the output end of the switch circuit, and the other end of the third resistor is grounded through the fourth resistor.
The beneficial effect who adopts above-mentioned scheme is: the voltage sampling detection circuit detects the voltage difference at two ends of the switch circuit after voltage division, and the voltage difference is used as one of references for duty ratio adjustment.
Further, the voltage sampling detection circuit further comprises an operational amplifier;
one end of the first resistor, which is connected with the second resistor, is connected with the inverting input end of the operational amplifier, and one end of the third resistor, which is connected with the fourth resistor, is connected with the non-inverting input end of the operational amplifier;
and the positive phase input end and the output end of the operational amplifier are respectively connected with the duty ratio regulating circuit.
The beneficial effect who adopts above-mentioned scheme is: the voltage difference is fed back to the duty ratio regulating circuit through the operational amplifier, so that the accuracy of data is guaranteed, and the duty ratio regulation is more scientific and reliable.
Further, the resistances of the first resistor, the second resistor, the third resistor and the fourth resistor are 100k ohms.
The beneficial effect who adopts above-mentioned scheme is: the lithium battery charger can be widely applied to charging lithium batteries of most small electric appliances on the market, and has wider application range.
Further, the duty cycle adjusting circuit comprises an MCU unit;
the MCU unit is connected with the voltage sampling detection circuit through a first input end and a second input end and is connected with the switch circuit through an output end.
The beneficial effect who adopts above-mentioned scheme is: the MCU unit is adopted as a duty ratio adjusting circuit, a user can set different current ranges according to different conditions, and the duty ratio adjusting circuit makes adjustment in a targeted manner to meet working requirements of different lithium batteries.
Further, the specific model of the MCU unit is FT61F 021A.
An average current constant type charging method applied to the average current constant type charging apparatus described above, the charging method comprising the steps of:
the voltage sampling detection circuit collects the voltage difference between the input end and the output end of the switch circuit;
the voltage sampling detection circuit feeds back the collected voltage difference to the duty ratio regulation circuit;
the duty ratio regulating circuit performs operation according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty ratio of the switching circuit;
the duty ratio adjusting circuit outputs a control signal to the switching circuit according to the duty ratio obtained by operation, and controls the switching circuit to be switched on and switched off through the control signal so as to control the average charging current of the lithium battery.
Compared with the prior art, the technical scheme has the beneficial effects that: the current of the lithium battery is not required to be additionally detected, the voltage difference at two ends of the switch circuit is only required to be detected through the voltage sampling detection circuit, the duty ratio is adjusted by controlling the state of the switch circuit through the duty ratio adjusting circuit, and then the average current is controlled to be in a constant state.
Further, the charging method further includes: judging the state of the lithium battery; correspondingly, the charging method comprises the following steps:
the voltage sampling detection circuit collects the voltage of the lithium battery and feeds the voltage back to the duty ratio adjusting circuit, and the duty ratio adjusting circuit judges the state of the lithium battery through the voltage of the lithium battery: when the voltage of the lithium battery reaches a full charge threshold value, the duty ratio adjusting circuit judges that the lithium battery is in an electric quantity saturation state, the duty ratio adjusting circuit controls the switching circuit to be cut off through a control signal, and the charging program is stopped; when the voltage of the lithium battery does not reach the full charge threshold value, the duty ratio adjusting circuit judges that the lithium battery is in an electric quantity unsaturated state, and executes the next step and a charging program;
the voltage sampling detection circuit collects the voltage difference between the input end and the output end of the switch circuit;
the voltage sampling detection circuit feeds back the collected voltage difference to the duty ratio regulation circuit;
the duty ratio regulating circuit performs operation according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty ratio of the switching circuit;
the duty ratio adjusting circuit outputs a control signal to the switching circuit according to the duty ratio obtained by operation, and controls the switching circuit to be switched on and switched off through the control signal so as to control the average charging current of the lithium battery.
The beneficial effect who adopts above-mentioned scheme is: before charging, the state of the lithium battery is judged. When the lithium battery is in an electric quantity saturation state, stopping a charging program; and when the lithium battery is in an electric quantity unsaturated state, executing a charging program.
Further, the duty cycle adjusting circuit specifically includes, by performing an operation according to the voltage difference detected by the voltage sampling detection circuit, the duty cycle of the switching circuit:
and the duty ratio regulating circuit calculates according to the voltage difference detected by the voltage sampling detection circuit and the preset working current to obtain the duty ratio of the switching circuit.
The beneficial effect who adopts above-mentioned scheme is: the user can conveniently formulate different charging schemes according to different lithium batteries.
Further, the duty ratio adjusting circuit preferably further reduces the duty ratio when the electric quantity of the lithium battery is close to full charge according to the voltage value of the lithium battery detected by the voltage sampling detection circuit, so that the average charging current is smaller.
Drawings
Fig. 1 is a schematic block diagram of an average current constant type charging apparatus according to the present invention.
Fig. 2 is a schematic diagram of an average current constant type charging apparatus according to the present invention.
In the figures, the list of components represented by the various reference numbers is as follows:
the charging system comprises a switch circuit U1, a voltage sampling detection circuit U2, a duty ratio adjusting circuit U3, a charging output port 1 and a lithium battery 2.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or assembly referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, and the two components can be communicated with each other. When an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the prior art, a rechargeable lithium battery is charged mainly by the following charging methods: the first method is as follows: and a diode is adopted for charging. Directly connecting a charger or a solar photovoltaic panel with a diode to directly charge a battery; in this way, the charging current is not constant, the current is not controllable, and the current has a great relation with the voltage of the charging device and the battery and has a great change. The second method comprises the following steps: and charging by adopting a linear voltage stabilizing circuit. For example, 4056 charging chips are adopted, but the current in the method is small and generally does not exceed 1 ampere, and when the capacity of the battery is large, the method is not applicable and the charging is slow. The third method comprises the following steps: and a switching power supply circuit is adopted for charging. There are buck-type or boost-type chips for charge control, which is costly, and the charging current has a large relationship with the charging device and the battery voltage, making the use inflexible. For lithium batteries, it is important to keep the average current constant during charging, and it is difficult to realize the average current constant with low cost in the prior art.
In order to solve the above problems, the present invention provides an average current constant charging apparatus and method, and aims to provide a low-cost and easy-to-implement charging control scheme, so that the average current is kept constant during the charging process of a lithium battery.
As shown in fig. 1, an average current constant type charging device includes a switching circuit U1, a voltage sampling detection circuit U2, and a duty ratio adjustment circuit U3. The input end of the switch circuit is connected with the charging output port 1, the output end of the switch circuit is connected with the lithium battery, and the input end of the voltage sampling detection circuit is respectively connected with the switch circuit and the lithium battery 2; the output end of the voltage sampling detection circuit is connected with the duty ratio adjusting circuit, and the duty ratio adjusting circuit is connected with the switching circuit. In the process of charging the lithium battery, the voltage sampling detection circuit is used for collecting the voltage difference between the input end and the output end of the switch circuit, and the duty ratio regulation circuit is used for controlling the on-off of the switch circuit according to the voltage difference detected by the voltage sampling detection circuit so as to control the average charging current of the lithium battery.
When the voltage sampling detection circuit works specifically, the voltage difference is input into the duty ratio regulation circuit after the voltage difference is detected, the duty ratio regulation circuit outputs a control signal to the switching circuit according to the voltage difference, and the on-off state of the switching circuit is controlled, so that the duty ratio regulation is carried out. Therefore, when the technical scheme of the invention is implemented, the current of the lithium battery does not need to be additionally detected, only the voltage difference between two ends of the switching circuit needs to be detected through the voltage sampling detection circuit, and then the duty ratio is adjusted by controlling the state of the switching circuit through the duty ratio adjusting circuit, so that the average current is controlled to be in a constant state.
As shown in fig. 2, the switching circuit preferably includes a PMOS transistor Q1; the grid of PMOS pipe Q1 with duty cycle regulating circuit links to each other, the source electrode of PMOS pipe Q1 with the delivery outlet that charges links to each other, the drain electrode of PMOS pipe Q1 with the lithium cell links to each other. The PMOS tube Q1 is connected with a duty ratio adjusting circuit through the grid electrode thereof, the duty ratio adjusting circuit only needs to control the level output to the grid electrode of the PMOS tube Q1, the state of the PMOS tube Q1 can be controlled, and the basic function of the switch circuit is realized through a simple circuit structure.
As shown in fig. 2, preferably, the voltage sampling detection circuit includes a first resistor, a second resistor, a third resistor and a fourth resistor; one end of the first resistor is connected with the input end of the switch circuit, and the other end of the first resistor is grounded through the second resistor; one end of the third resistor is connected with the output end of the switch circuit, and the other end of the third resistor is grounded through the fourth resistor. The voltage sampling detection circuit detects the voltage difference at two ends of the switch circuit after voltage division, and the voltage difference is used as one of references for duty ratio adjustment.
Specifically, the resistance values of the first resistor, the second resistor, the third resistor and the fourth resistor are 100k ohms, and the resistor setting can be widely applied to charging lithium batteries of most small-sized electric appliances on the market, so that the application range is wider. Of course, in the specific implementation process, a technician may set the voltage dividing resistor to have different resistance values according to actual conditions.
As shown in fig. 2, preferably, the voltage sampling detection circuit further includes an operational amplifier; one end of the first resistor, which is connected with the second resistor, is connected with the inverting input end of the operational amplifier, and one end of the third resistor, which is connected with the fourth resistor, is connected with the non-inverting input end of the operational amplifier; and the positive phase input end and the output end of the operational amplifier are respectively connected with the duty ratio regulating circuit. The voltage difference is fed back to the duty ratio regulating circuit through the operational amplifier, so that the accuracy of data is guaranteed, and the duty ratio regulation is more scientific and reliable.
It should be noted that, the duty cycle adjusting circuit obtains the voltage difference through the output end of the operational amplifier in the voltage sampling detection circuit, and obtains the real-time electric quantity of the lithium battery through the end of the third resistor connected with the fourth resistor, and then judges the state of the lithium battery through the real-time electric quantity: when the voltage obtained after voltage division is performed on the third resistor and the fourth resistor is higher than a certain charging threshold value, the lithium battery is in a state of electric quantity saturation, and otherwise, the lithium battery is in a state of electric quantity unsaturation.
As shown in fig. 2, preferably, the duty cycle adjusting circuit includes an MCU unit; the MCU unit is connected with the voltage sampling detection circuit through a first input end and a second input end and is connected with the switch circuit through an output end. The MCU unit is adopted as a duty ratio adjusting circuit, a user can set different current ranges according to different conditions, and the duty ratio adjusting circuit makes adjustment in a targeted manner to meet working requirements of different lithium batteries.
Specifically, the specific model of the MCU unit is FT61F 021A. In the specific implementation process, technicians can adopt chips of different models as the MCU unit according to actual conditions, and the chips are only required to have the functions of detecting different input voltages or AD sampling and have high and low level output functions.
An average current constant type charging method, which applies the average current constant type charging device, comprises the following steps:
s1, a voltage sampling detection circuit collects a voltage difference between an input end and an output end of a switch circuit;
s2, feeding back the acquired voltage difference to a duty ratio adjusting circuit by a voltage sampling detection circuit;
s3, the duty ratio adjusting circuit performs operation according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty ratio of the switching circuit;
and S4, the duty ratio adjusting circuit outputs a control signal to the switching circuit according to the duty ratio obtained by operation, and controls the switching circuit to be switched on and switched off through the control signal so as to control the average charging current of the lithium battery.
Preferably, before the charging, the charging method further comprises: judging the state of the lithium battery; correspondingly, the charging method comprises the following steps:
the voltage sampling detection circuit collects the voltage of the lithium battery and feeds the voltage back to the duty ratio adjusting circuit, and the duty ratio adjusting circuit judges the state of the lithium battery through the voltage of the lithium battery: when the voltage of the lithium battery reaches a full charge threshold value, the duty ratio adjusting circuit judges that the lithium battery is in an electric quantity saturation state, the duty ratio adjusting circuit controls the switching circuit to be cut off through a control signal, and the charging program is stopped; when the voltage of the lithium battery does not reach the full charge threshold value, the duty ratio adjusting circuit judges that the lithium battery is in an electric quantity unsaturated state, and executes the next step and a charging program;
the voltage sampling detection circuit collects the voltage difference between the input end and the output end of the switch circuit;
the voltage sampling detection circuit feeds back the collected voltage difference to the duty ratio regulation circuit;
the duty ratio regulating circuit performs operation according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty ratio of the switching circuit;
the duty ratio adjusting circuit outputs a control signal to the switching circuit according to the duty ratio obtained by operation, and controls the switching circuit to be switched on and switched off through the control signal so as to control the average charging current of the lithium battery.
Based on the scheme, the state of the lithium battery is judged before charging. When the lithium battery is in an electric quantity saturation state, stopping a charging program; and when the lithium battery is in an electric quantity unsaturated state, executing a charging program. In this way, different charging schemes are implemented in combination with the actual situation of the lithium battery.
Preferably, the operation of the duty cycle adjusting circuit according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty cycle of the switching circuit specifically includes:
and the duty ratio regulating circuit calculates according to the voltage difference detected by the voltage sampling detection circuit and the preset working current to obtain the duty ratio of the switching circuit.
Different lithium batteries correspond different optimal charging currents, the user presets the optimal charging current through the duty ratio adjusting circuit according to actual conditions, at the moment, the duty ratio adjusting circuit performs calculation and analysis in combination with the voltage difference to obtain the duty ratio corresponding to the optimal charging current and the voltage difference, and therefore the user can conveniently make different charging schemes according to different lithium batteries.
The technical solution of the present invention will be described in detail with reference to fig. 1 and 2.
In the present embodiment, on the one hand, when the switch circuit is turned on, the on-resistance of the switch circuit is Ron; on the other hand, when the switching circuit is turned on, the voltage difference between the input terminal and the output terminal thereof is Δ V.
According to ohm's law, when the switching circuit is in the on state, the current I flowing through is Δ V/Ron; when the switch circuit is in the off state, the current flowing through the switch circuit is zero. In this case, the on duty ratio of the switching circuit is D, and it can be found that the average current Iavg ═ I ═ D ═ Δ V ═ D)/Ron of the switching circuit at this time.
As can be seen from fig. 1 and fig. 2, in the present embodiment, the switching circuit is U1, the voltage sampling detection circuit is U2, and the duty ratio adjustment circuit is U3. When the voltage sampling detection circuit U2 detects that the battery capacity is insufficient through the resistance voltage division of the third resistor R3 and the fourth resistor R4, the battery is charged. At this time, when the switch circuit is turned on and off, voltages at an input end and an output end of the switch circuit may change, a voltage difference between two ends of the switch circuit U1, which is detected by the switch circuit U1 through the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 by voltage division, is Δ V0, the switch circuit U1 inputs the voltage difference Δ V0 to the duty ratio adjusting circuit U3, and the duty ratio adjusting circuit U3 obtains a duty ratio D0 corresponding to the voltage difference VO by performing operation, wherein D0 is (Ron × Iavg)/Δ V0.
Analysis of FIG. 2:
the voltage difference between the input end and the output end of the switching circuit is delta Vn-Vi-Vo;
the voltage at the input end of the switching circuit is Vi ═ Vp0 ═ (R1+ R2)/R2;
the voltage at the output end of the switching circuit is VO ═ Vp1 ═ (R3+ R4)/R4;
wherein Vp0 is the voltage of the connection point of R1 and R2, Vp1 is the voltage of the connection point of R3 and R4;
thus, it can be seen that
ΔVn＝Vp0*(R1+R2)/R2-Vp1*(R3+R4)/R4
In the present example, it is shown that,
R1-R2-R3-R4, then
ΔVn＝2*(Vp0-Vp1)
Therefore, as long as Vp0-Vp1 is detected, Δ Vn is obtained, and Ron is the on-resistance of the switch circuit, which is a fixed property of hardware, and is approximately constant. The average current Iavg corresponds to the duty ratio D0 one by one, and the duty ratio D0 can be obtained by setting the target average current.
In the present embodiment, it is only necessary to keep Δ V0 × D0 ═ Δ V1 × D1 ═ … … ═ Δ Vn × Dn, so that the average current of the lithium battery is constant during the charging process, and the average current Iavg ═ I ═ D ═ Δ Vn × Dn)/Ron.
Therefore, the voltage difference between the input end and the output end when the switching circuit is switched on is obtained through the voltage sampling detection circuit, then the duty ratio is calculated through the duty ratio adjusting circuit, and the switching circuit is controlled to be switched on and switched off, so that the constancy of the average current is realized. The constant average current can be maintained as long as the charging device is able to provide sufficient current.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.
Claims (10)
1. The average current constant type charging device is characterized by comprising a switching circuit, a voltage sampling detection circuit and a duty ratio regulation circuit;
the input end of the switch circuit is connected with a charging output port, the output end of the switch circuit is connected with a lithium battery, and the input end of the voltage sampling detection circuit is respectively connected with the switch circuit and the lithium battery; the output end of the voltage sampling detection circuit is connected with the duty cycle adjusting circuit, and the output end of the duty cycle adjusting circuit is connected with the switching circuit;
the voltage sampling detection circuit is used for collecting the voltage difference between the input end and the output end of the switch circuit;
the duty ratio adjusting circuit is used for controlling the on and off of the switch circuit according to the voltage difference detected by the voltage sampling detection circuit, and further controlling the average charging current of the lithium battery.
2. The average current constant charging device according to claim 1, wherein the switching circuit comprises a PMOS transistor;
the grid electrode of the PMOS tube is connected with the duty ratio adjusting circuit, the source electrode of the PMOS tube is connected with the charging output port, and the drain electrode of the PMOS tube is connected with the lithium battery.
3. The average current constant charging device according to claim 1, wherein the voltage sampling detection circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
one end of the first resistor is connected with the input end of the switch circuit, and the other end of the first resistor is grounded through the second resistor;
one end of the third resistor is connected with the output end of the switch circuit, and the other end of the third resistor is grounded through the fourth resistor.
4. The average current constant charging device according to claim 3, wherein the voltage sampling detection circuit further comprises an operational amplifier;
one end of the first resistor, which is connected with the second resistor, is connected with the inverting input end of the operational amplifier, and one end of the third resistor, which is connected with the fourth resistor, is connected with the non-inverting input end of the operational amplifier;
and the positive phase input end and the output end of the operational amplifier are respectively connected with the duty ratio regulating circuit.
5. The average current constant charging device according to claim 3, wherein the first resistor, the second resistor, the third resistor and the fourth resistor have a resistance of 100k ohms.
6. The average current constant charging device according to claim 1, wherein the duty cycle adjusting circuit comprises an MCU unit;
the MCU unit is connected with the voltage sampling detection circuit through a first input end and a second input end and is connected with the switch circuit through an output end.
7. The device as claimed in claim 5, wherein the MCU unit has a specific model number FT61F 021A.
8. An average current constant charging method applied to the average current constant charging apparatus according to any one of claims 1 to 9, characterized by comprising the steps of:
the voltage sampling detection circuit collects the voltage difference between the input end and the output end of the switch circuit;
the voltage sampling detection circuit feeds back the collected voltage difference to the duty ratio regulation circuit;
the duty ratio regulating circuit performs operation according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty ratio of the switching circuit;
the duty ratio adjusting circuit outputs a control signal to the switching circuit according to the duty ratio obtained by operation, and controls the switching circuit to be switched on and switched off through the control signal so as to control the average charging current of the lithium battery.
9. The constant-average-current charging method according to claim 8, further comprising: judging the state of the lithium battery; correspondingly, the charging method comprises the following steps:
the voltage sampling detection circuit collects the voltage of the lithium battery and feeds the voltage back to the duty ratio adjusting circuit, and the duty ratio adjusting circuit judges the state of the lithium battery through the voltage of the lithium battery: when the voltage of the lithium battery reaches a full charge threshold value, the duty ratio adjusting circuit judges that the lithium battery is in an electric quantity saturation state, the duty ratio adjusting circuit controls the switching circuit to be cut off through a control signal, and the charging program is stopped; when the voltage of the lithium battery does not reach the full charge threshold value, the duty ratio adjusting circuit judges that the lithium battery is in an electric quantity unsaturated state, and executes the next step and a charging program;
the voltage sampling detection circuit collects the voltage difference between the input end and the output end of the switch circuit;
the voltage sampling detection circuit feeds back the collected voltage difference to the duty ratio regulation circuit;
the duty ratio regulating circuit performs operation according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty ratio of the switching circuit;
the duty ratio adjusting circuit outputs a control signal to the switching circuit according to the duty ratio obtained by operation, and controls the switching circuit to be switched on and switched off through the control signal so as to control the average charging current of the lithium battery.
10. The method according to claim 8 or 9, wherein the operation of the duty cycle adjusting circuit according to the voltage difference detected by the voltage sampling detection circuit to obtain the duty cycle of the switching circuit specifically comprises:
and the duty ratio regulating circuit calculates according to the voltage difference detected by the voltage sampling detection circuit and the preset working current to obtain the duty ratio of the switching circuit.
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| CN116505631A (en) * | 2023-06-29 | 2023-07-28 | 深圳市微源半导体股份有限公司 | Single-input multi-output charging circuit and wearable device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116505631A (en) * | 2023-06-29 | 2023-07-28 | 深圳市微源半导体股份有限公司 | Single-input multi-output charging circuit and wearable device |
| CN116505631B (en) * | 2023-06-29 | 2024-02-09 | 深圳市微源半导体股份有限公司 | Single-input multi-output charging circuit and wearable device |
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