CN216699567U - Charging circuit and charging equipment based on PWM control - Google Patents
Charging circuit and charging equipment based on PWM control Download PDFInfo
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- CN216699567U CN216699567U CN202123261844.6U CN202123261844U CN216699567U CN 216699567 U CN216699567 U CN 216699567U CN 202123261844 U CN202123261844 U CN 202123261844U CN 216699567 U CN216699567 U CN 216699567U
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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
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Abstract
The utility model discloses a charging circuit and charging equipment based on PWM control, wherein the charging circuit comprises a first resistor, a sampling resistor, an MOS (metal oxide semiconductor) tube and a differential amplification circuit unit, the source electrode of the MOS tube is used for being connected with the positive end of a charger, the drain electrode of the MOS tube is used for being connected with the positive end of a rechargeable battery, the grid electrode of the MOS tube is used for being connected with a PWM interface, the two ends of the first resistor are respectively connected with the source electrode and the grid electrode of the MOS tube, the negative end of the rechargeable battery is grounded, the two ends of the sampling resistor are respectively connected with the negative end of the rechargeable battery and the negative end of the charger, the differential amplification circuit unit is used for detecting charging current, the non-inverting input end of the differential amplification circuit unit is connected with the negative end of the rechargeable battery, the inverting input end of the differential amplification circuit unit is connected with the negative end of the charger, and the output end of the differential amplification circuit unit is connected with the ADC port of a single chip microcomputer. The charging circuit and the charging equipment provided by the utility model replace an expensive charging management chip, so that the cost is greatly reduced, and the charging circuit and the charging equipment can be compatible with different numbers of rechargeable batteries.
Description
Technical Field
The utility model relates to the technical field of charging voltage adjustment output, in particular to a charging circuit based on PWM control and charging equipment.
Background
In the field of small household appliances, a lithium battery is usually used as a power supply, battery charging is an important link, if overcharge often causes irreversible damage to the lithium battery, a special charging management chip is often used in the prior art, which can certainly well realize charging management of the lithium battery, but the scheme has high cost, the price of the lithium battery charging management chip is expensive, and great cost pressure is caused to the small household appliances with high cost requirements; and different lithium battery charging management chips are required to be applied to the combined batteries with different sections in the product, so that the model selection is difficult to a certain degree. It is therefore desirable to provide a low cost lithium battery charging management solution.
SUMMERY OF THE UTILITY MODEL
In order to solve the problems in the prior art, the utility model provides a charging circuit and a charging device based on PWM control, and the technical scheme is as follows:
on the one hand, the charging circuit based on PWM control is provided, including first resistance, sampling resistor, MOS pipe and difference amplifier circuit unit, the source electrode of MOS pipe is used for inserting the positive end of charger, and its drain electrode is used for inserting rechargeable battery's positive end, and its grid is used for inserting the PWM interface, the both ends of first resistance are inserted respectively the source electrode and the grid of MOS pipe, rechargeable battery's negative terminal ground connection, sampling resistor's both ends are inserted respectively rechargeable battery's negative terminal with the negative terminal of charger, difference amplifier circuit unit is used for detecting charging current, the homophase input of difference amplifier circuit unit inserts rechargeable battery's negative terminal, and its inverting input inserts the negative terminal of charger, and its output inserts the ADC port of singlechip.
Further, the differential amplification circuit unit comprises a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor and an operational amplifier, wherein two ends of the third resistor are respectively connected to the negative terminal of the rechargeable battery and the non-inverting input terminal of the operational amplifier, and two ends of the fifth resistor are respectively connected to the negative terminal of the charger and the inverting input terminal of the operational amplifier; one end of the second resistor is connected to the non-inverting input end of the operational amplifier, the other end of the second resistor is grounded, two ends of the sixth resistor are connected to the inverting input end and the output end of the operational amplifier respectively, one end of the fourth resistor is connected to the output end of the operational amplifier, the other end of the fourth resistor is connected to the ADC port of the single chip microcomputer and is connected with one end of the first capacitor, and the other end of the first capacitor is grounded.
Further, the resistance value of the third resistor is equal to that of the fifth resistor, and the resistance value of the second resistor is equal to that of the sixth resistor.
Furthermore, the differential amplification circuit unit further comprises a seventh resistor, an eighth resistor, a second capacitor and a third capacitor, wherein one end of the seventh resistor is connected to the negative terminal of the rechargeable battery, the other end of the seventh resistor is connected to the third resistor and is simultaneously connected to one end of the second capacitor, and the other end of the second capacitor is grounded; one end of the eighth resistor is connected to the negative end of the charger, the other end of the eighth resistor is connected to the fifth resistor and is connected to one end of the third capacitor, and the other end of the third capacitor is grounded.
Further, the resistance value of the seventh resistor is equal to that of the eighth resistor.
Furthermore, the differential amplification circuit unit further comprises a fourth capacitor, and two ends of the fourth capacitor are respectively connected to the non-inverting input end and the inverting input end of the operational amplifier.
Further, the charging circuit based on the PWM control further comprises a diode, wherein the anode of the diode is connected to the positive end of the charger, and the cathode of the diode is connected to the source electrode of the MOS tube.
Furthermore, the charging circuit based on the PWM control further includes a triode, a ninth resistor and a tenth resistor, wherein an emitter of the triode is grounded, a base of the triode is connected to the PWM interface, a collector of the triode is connected to one end of the ninth resistor, the other end of the ninth resistor is connected to a gate of the MOS transistor, and two ends of the tenth resistor are respectively connected to the base and the emitter of the triode.
Further, the charging circuit based on the PWM control further includes a fifth capacitor connected in parallel to two ends of the first resistor.
In another aspect, a charging device is provided, which includes the above-mentioned charging circuit based on PWM control.
The technical scheme provided by the utility model has the following beneficial effects:
a. an expensive charging management chip is replaced, so that the cost is greatly reduced;
b. the charging device can be compatible with different numbers of charging batteries for stable charging, and has strong applicability.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic diagram of a first circuit structure of a charging circuit based on PWM control according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a second circuit structure of the charging circuit based on PWM control according to the embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, 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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the utility model described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.
In an embodiment of the present invention, a charging circuit based on PWM control is provided, and referring to fig. 1, the charging circuit includes a first resistor R1, a sampling resistor RES1, a MOS transistor Q1, and a differential amplifier circuit unit, where a source of the MOS transistor is used to connect to a positive terminal of a charger, a drain of the MOS transistor is used to connect to a positive terminal of a rechargeable battery, and a gate of the MOS transistor is used to connect to a PWM interface, the MOS transistor is preferably a P-type MOS transistor, and the rechargeable battery is preferably a lithium battery;
the utility model discloses a charging device, including sampling resistor, sampling amplifier, source electrode, grid, differential amplifier circuit unit, charging current flow sampling resistor, sampling amplifier, charging current source, grid, sampling resistor, sampling amplifier, differential amplifier circuit unit, charging current source and grid, the both ends of first resistance are accessed respectively the source electrode and the grid of MOS pipe, charging battery's negative terminal ground connection, sampling resistor's both ends are accessed respectively charging battery's negative terminal with the negative terminal of charger, differential amplifier circuit unit is used for detecting charging current, and charging current flows through sampling resistor and forms differential voltage, acquires actual charging current through the singlechip behind the differential amplifier to with this output of adjusting the PWM interface is in order to realize the adjustment to charging current, the homophase input of differential amplifier circuit unit is accessed charging battery's negative terminal, its inverting input inserts the negative terminal of charger, its output inserts the ADC port of singlechip.
Specifically, referring to fig. 1, the differential amplifier circuit unit includes a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first capacitor C1, and an operational amplifier U1, where a resistance value of the third resistor is equal to that of the fifth resistor, and a resistance value of the second resistor is equal to that of the sixth resistor. Two ends of the third resistor are respectively connected to the negative end of the rechargeable battery and the non-inverting input end of the operational amplifier, and two ends of the fifth resistor are respectively connected to the negative end of the charger and the inverting input end of the operational amplifier; one end of the second resistor is connected to the non-inverting input end of the operational amplifier, the other end of the second resistor is grounded, two ends of the sixth resistor are connected to the inverting input end and the output end of the operational amplifier respectively, one end of the fourth resistor is connected to the output end of the operational amplifier, the other end of the fourth resistor is connected to the ADC port of the single chip microcomputer and is connected with one end of the first capacitor, and the other end of the first capacitor is grounded.
In order to reduce circuit fluctuation and make the circuit operation more smooth, referring to fig. 2, the differential amplifier circuit unit further includes a seventh resistor R7, an eighth resistor R8, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4, wherein the seventh resistor has a resistance equal to the eighth resistor. One end of the seventh resistor is connected to the negative end of the rechargeable battery, the other end of the seventh resistor is connected to the third resistor and is simultaneously connected with one end of the second capacitor, and the other end of the second capacitor is grounded; one end of the eighth resistor is connected to the negative end of the charger, the other end of the eighth resistor is connected to the fifth resistor and is simultaneously connected to one end of the third capacitor, the other end of the third capacitor is grounded, and two ends of the fourth capacitor are respectively connected to the non-inverting input end and the inverting input end of the operational amplifier.
When current flows through the sampling resistor, a differential voltage is formed on the sampling resistor, the voltage point of the negative end of the rechargeable battery at one side of the differential voltage is filtered through a seventh resistor and a second capacitor, the voltage point of the negative end of the charger at the other side of the differential voltage is filtered through an eighth resistor and a third capacitor, the differential voltage is further filtered through a third resistor, a fourth capacitor and a fifth resistor to form a differential voltage of a point a and a point b, and the differential voltage is respectively connected to the non-inverting input end and the inverting input point of the operational amplifier by referring to the figure 2, meanwhile, a differential amplifying circuit is formed by matching the second resistor and the sixth resistor, a voltage point c is output at the output end of the operational amplifier after the differential voltage is amplified, the voltage c is filtered by a filter circuit consisting of the fourth resistor and the first capacitor to output a voltage which is recorded as AD _ CUR and is connected and output to an ADC port of the singlechip. The PWM interface can adjust the output of the charging current acquired by the ADC port, and can be an interface carried by the device to be charged or a corresponding interface arranged on the singlechip.
When the rechargeable battery needs to be charged, a charger is inserted, if the voltage of the rechargeable battery is lower, the single chip microcomputer sets a smaller trickle charging current, an ADC (analog to digital converter) port of the single chip microcomputer reads the charging current and compares the charging current with the set charging current, if the actually read charging current is smaller, the duty ratio of the PWM is adjusted in the direction of increasing the charging current, namely the output duty ratio of the PWM interface needs to be increased, if the actually read charging current is larger, the duty ratio of the PWM is adjusted in the direction of reducing the charging current, namely the output duty ratio of the PWM interface needs to be reduced, and the linear state of the work of the MOS tube is adjusted by adjusting the PWM; when the voltage of the battery rises to a certain value, the single chip microcomputer increases the charging current to carry out constant current charging, and the PWM duty ratio of the single chip microcomputer is adjusted towards the current increasing direction until the collected charging current is equal to the set constant current charging current; when the battery is nearly fully charged, such as 85% full, it is charged in a trickle charge until the battery is fully charged. In the adjustment process of the software PWM, effective software filtering is carried out on the sampling charging current of the ADC port, and the accuracy of the charging current is greatly improved.
In order to prevent the reverse connection of the charging power supply, the charging circuit based on the PWM control further includes a diode D1, the diode is a backward flow diode, preferably a schottky diode, an anode of the diode is connected to the positive terminal of the charger, and a cathode of the diode is connected to the source of the MOS transistor.
In order to charge a lithium battery with more sections, the input voltage of the charger is divided to avoid breaking down the MOS transistor, specifically, the charging circuit based on PWM control further includes a transistor Q2, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11 and a fifth capacitor C5, the emitter of the transistor is grounded, the base of the transistor is connected to the PWM interface through the eleventh resistor, the collector of the transistor is connected to one end of the ninth resistor, the other end of the ninth resistor is connected to the gate of the MOS transistor, the two ends of the tenth resistor are connected to the base and the emitter of the transistor respectively, and the fifth capacitor is connected to the two ends of the first resistor in parallel.
In one embodiment of the utility model, a charging device is provided, which comprises the charging circuit based on the PWM control. The charging equipment stably charges the lithium battery, and adjusts corresponding charging current by utilizing the single chip microcomputer according to the charging degree, for example, when the charging battery is initially at low voltage, small trickle current is adopted for charging, a certain voltage is changed into large current for charging, and when the charging battery is quickly charged, trickle charging is adopted. The idea of the embodiment of the charging device and the working process of the charging circuit based on PWM control in the above embodiment belong to the same idea, and the entire content of the embodiment of the voltage dynamic adjustment circuit is incorporated into the embodiment of the charging device by full reference, which is not described again.
The charging circuit and the charging equipment based on PWM control provided by the utility model replace a special lithium battery charging management chip by using simple circuit elements, so that the cost is greatly reduced, the current feedback data is more accurate, the regulation speed is high, the anti-interference capability is strong, and the reliability is high.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. The utility model provides a charging circuit based on PWM control, its characterized in that, includes first resistance, sampling resistor, MOS pipe and difference amplifier circuit unit, the source electrode of MOS pipe is used for inserting the positive end of charger, and its drain electrode is used for inserting rechargeable battery's positive end, and its grid is used for inserting the PWM interface, the both ends of first resistance are inserted respectively the source electrode and the grid of MOS pipe, rechargeable battery's negative terminal ground connection, sampling resistor's both ends are inserted respectively rechargeable battery's negative terminal with the negative terminal of charger, difference amplifier circuit unit is used for detecting charging current, the homophase input of difference amplifier circuit unit inserts rechargeable battery's negative terminal, and its inverting input inserts the negative terminal of charger, and its output is used for inserting the ADC port of singlechip.
2. The charging circuit based on PWM control according to claim 1, wherein the differential amplification circuit unit comprises a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor and an operational amplifier, two ends of the third resistor are respectively connected to a negative terminal of the rechargeable battery and a non-inverting input terminal of the operational amplifier, and two ends of the fifth resistor are respectively connected to a negative terminal of the charger and an inverting input terminal of the operational amplifier; one end of the second resistor is connected to the non-inverting input end of the operational amplifier, the other end of the second resistor is grounded, two ends of the sixth resistor are connected to the inverting input end and the output end of the operational amplifier respectively, one end of the fourth resistor is connected to the output end of the operational amplifier, the other end of the fourth resistor is connected to the ADC port of the single chip microcomputer and is connected with one end of the first capacitor, and the other end of the first capacitor is grounded.
3. The charging circuit based on PWM control according to claim 2, wherein the third resistor has a resistance equal to a fifth resistor, and the second resistor has a resistance equal to a sixth resistor.
4. The charging circuit based on the PWM control according to claim 2, wherein the differential amplifying circuit unit further comprises a seventh resistor, an eighth resistor, a second capacitor and a third capacitor, wherein one end of the seventh resistor is connected to the negative terminal of the rechargeable battery, the other end of the seventh resistor is connected to the third resistor and is connected to one end of the second capacitor, and the other end of the second capacitor is grounded; one end of the eighth resistor is connected to the negative end of the charger, the other end of the eighth resistor is connected to the fifth resistor and is connected to one end of the third capacitor, and the other end of the third capacitor is grounded.
5. The PWM-control-based charging circuit according to claim 4, wherein a resistance value of the seventh resistor is equal to that of the eighth resistor.
6. The charging circuit based on PWM control of claim 4, wherein the differential amplification circuit unit further comprises a fourth capacitor, and two ends of the fourth capacitor are respectively connected to a non-inverting input terminal and an inverting input terminal of the operational amplifier.
7. The charging circuit based on PWM control according to claim 1, further comprising a diode, wherein an anode of the diode is connected to the positive terminal of the charger, and a cathode of the diode is connected to the source of the MOS transistor.
8. The charging circuit based on the PWM control according to claim 1, further comprising a triode, a ninth resistor and a tenth resistor, wherein an emitter of the triode is grounded, a base of the triode is connected to the PWM interface, a collector of the triode is connected to one end of the ninth resistor, the other end of the ninth resistor is connected to a gate of the MOS transistor, and two ends of the tenth resistor are respectively connected to the base and the emitter of the triode.
9. The charging circuit based on PWM control according to claim 1, further comprising a fifth capacitor connected in parallel across the first resistor.
10. A charging apparatus comprising the PWM control-based charging circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123261844.6U CN216699567U (en) | 2021-12-23 | 2021-12-23 | Charging circuit and charging equipment based on PWM control |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123261844.6U CN216699567U (en) | 2021-12-23 | 2021-12-23 | Charging circuit and charging equipment based on PWM control |
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| Publication Number | Publication Date |
|---|---|
| CN216699567U true CN216699567U (en) | 2022-06-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123261844.6U Active CN216699567U (en) | 2021-12-23 | 2021-12-23 | Charging circuit and charging equipment based on PWM control |
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| CN (1) | CN216699567U (en) |
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2021
- 2021-12-23 CN CN202123261844.6U patent/CN216699567U/en active Active
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