CN220421450U - Battery charging circuit - Google Patents

Abstract

The battery charging circuit that this application provided includes: a first charging port; a second charging port; the positive electrode of the battery is connected with the first charging port; the sampling control module is connected with the cathode of the battery and is used for sampling the current flowing through the battery and generating a driving signal according to the current flowing through the battery; the current limiting module is connected with the sampling control module and the second charging port and is used for controlling current flowing through the battery according to the driving signal. The scheme can improve the accuracy of the charging circuit in regulating and controlling the charging current of the battery.

Description

Battery charging circuit

Technical Field

The application relates to the technical field of battery charging, in particular to a battery charging circuit.

Background

In the existing energy storage equipment, power supply equipment such as a charger is generally adopted to charge an energy storage battery, in actual charging, the power supply voltage provided by the charger is constant, and a voltage difference exists between the voltage provided by the charger and the voltage of the battery, so that charging current is large, and a battery charging circuit is required to have a current limiting function to limit the charging current in order to avoid damage of the battery caused by the large charging current.

In the related art, a current limiting module and a sampling module are arranged in a common power supply circuit, the current limiting module is connected between the negative electrode of the battery and the negative electrode of the charger, the sampling module is connected between the output end of the current limiting module and the negative electrode of the charger, the sampling module is used for sampling the current of the output end of the current limiting module, and the current limiting module regulates and controls the charging current according to the sampled current. However, the charging circuit in the related art has low accuracy in regulating the charging current of the battery.

Disclosure of Invention

The application provides a battery charging circuit, and aims to solve the problem that the charging circuit in the related art is low in accuracy of charging current regulation and control of a battery.

The application provides a battery charging circuit, including: a first charging port; a second charging port; the positive electrode of the battery is connected with the first charging port; the sampling control module is connected with the negative electrode of the battery and is used for sampling the current flowing through the battery and generating a driving signal according to the current flowing through the battery; the current limiting module is connected with the sampling control module and the second charging port and is used for regulating and controlling the charging current of the battery according to the driving signal.

Optionally, the current limiting module includes: the transformer comprises a primary winding and a secondary winding, and the input end of the primary winding is connected with the sampling control module; the output end of the secondary winding is connected with the second charging port and grounded; the control end of the first switching element is connected with the sampling control module, one end of the first switching element is connected with the output end of the primary winding, and the other end of the first switching element is connected with the second charging port and grounded; one end of the first capacitor is connected with the other end of the sampling control module and the input end of the primary winding, and the other end of the first capacitor is grounded; the positive electrode of the first diode is connected with the output end of the secondary winding, and the negative electrode of the first diode is connected with the first charging port and the positive electrode of the battery.

Optionally, the sampling control module includes: the sampling unit is used for collecting current flowing through the battery; and one end of the control unit is connected with the other end of the sampling unit, the other end of the control unit is connected with the control end of the first switching element, and the control unit is used for generating a driving signal for controlling the first switching element to be switched on and off according to the current flowing through the battery.

Optionally, the sampling unit includes: one end of the sampling resistor is connected with the negative electrode of the battery, and the other end of the sampling resistor is connected with the current limiting module; the non-inverting input end of the first operational amplifier is connected with one end of the sampling resistor, the inverting input end of the first operational amplifier is connected with the other end of the sampling resistor, and the output end of the first operational amplifier is connected with the control unit.

Optionally, the sampling unit further includes: one end of the first resistor is connected with the output end of the first operational amplifier; one end of the second capacitor is connected with the output end of the first operational amplifier and one end of the first resistor; the non-inverting input end of the second operational amplifier is connected with the other end of the first resistor, the inverting input end of the second operational amplifier is connected with the other end of the second capacitor, and the output end of the second operational amplifier is connected with the control unit; and one end of the second diode is connected with the output end of the second operational amplifier and the control unit, and the other end of the second diode is grounded.

Optionally, the control unit includes: the input end of the micro control unit is connected with the output end of the first operational amplifier, and the output end of the micro control unit is connected with the control end of the first switching element.

Optionally, the control unit further includes: the control end of the second switching element is connected with the output end of the micro control unit, one end of the second switching element is grounded, and the ground of one end of the second switching element is different from the ground of the current module; the primary side input end of the photoelectric coupler receives a first power supply signal, the primary side output end of the photoelectric coupler is connected with the other end of the second switching element, the secondary side input end of the photoelectric coupler receives a second power supply signal, the first output end of the secondary side of the photoelectric coupler is connected with the control end of the first switching element, and the second output end of the secondary side of the photoelectric coupler is grounded; the first output end of the photoelectric coupler outputs a first level for controlling the first switching element to be switched on when the second switching element is switched on, and outputs a second level for controlling the first switching element to be switched off when the second switching element is switched off.

Optionally, the battery charging circuit further includes: one end of the reverse connection preventing module is connected with the first charging port, and the other end of the reverse connection preventing module is connected with the negative electrode of the first diode; the reverse connection prevention module is used for establishing connection between the first charging port and the first diode when the first charging port is connected with the positive electrode of the charger, and disconnecting connection between the first charging port and the first diode when the first charging port is connected with the negative electrode of the charger.

Optionally, the anti-reverse connection module includes: the voltage division unit is connected with the first charging port and the second charging port and is used for outputting a first level when the first charging port is connected with the positive electrode of the charger and outputting a second level when the first charging port is connected with the negative electrode of the charger; the control end of the fourth switching element is connected with the voltage dividing unit, and one end of the fourth switching element is grounded; the fourth switching element is used for being conducted when the voltage division unit outputs a first level and being disconnected when the voltage division unit outputs a second level; the control end of the third switching element is connected with the other end of the fourth switching element, one end of the third switching element is connected with the first charging port, the other end of the third switching element is connected with the negative electrode of the first diode, and the third switching element is used for being conducted when the fourth switching element is conducted and disconnected when the fourth switching element is disconnected.

Optionally, the voltage dividing unit includes: the emitter of the first triode is connected with the control end of the fourth switching element, and the collector of the first triode is connected with the first charging port; an emitter of the second triode is connected with a base electrode of the first triode, and an emitter of the second triode is connected with the first charging port; the anode of the voltage stabilizing diode is connected with the second charging port, and the cathode of the voltage stabilizing diode is connected with the base electrode of the second triode; and one end of the second resistor is connected with the grid electrode of the first triode and the emitter electrode of the second triode, and the other end of the second resistor is connected with the anode of the voltage stabilizing diode, the second diode of the charger and the second charging port.

Optionally, the transformer is a flat-plate transformer.

In the battery charging circuit that this application provided, sampling control module is connected with the negative pole of battery, and the direct sampling flows through the electric current of battery, and current limiting module adjusts present charge current according to the electric current of sampling to realize the current limiting to the charge current of battery. Compared with the related art, the sampling control module in the embodiment is connected between the negative electrode of the battery and the current limiting module, so that the current collected by the sampling control module is consistent with the charging current of the battery, and the accuracy of the charging circuit in regulating and controlling the charging current of the battery can be improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the embodiments of the application and together with the description, serve to explain the principles of the embodiments of the application.

Specific embodiments thereof have been shown by way of example in the drawings and will herein be described in more detail. These drawings and the written description are not intended to limit the scope of the inventive concepts of the embodiments in any way, but rather to illustrate the concepts of the embodiments of the present application to those skilled in the art by reference to the specific embodiments.

FIG. 1 is a schematic diagram of an exemplary application scenario of a battery charging circuit;

fig. 2 is a schematic structural diagram of a battery charging circuit according to a first embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of another battery charging circuit according to the first embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of another battery charging circuit according to the first embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of another battery charging circuit according to the first embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of another battery charging circuit according to the first embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a battery charging circuit according to a second embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of another battery charging circuit according to the second embodiment of the present application.

Specific embodiments thereof have been shown by way of example in the drawings and will herein be described in more detail. These drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples are not representative of all implementations consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application as detailed in the accompanying claims.

Fig. 1 is a schematic diagram of an application scenario of a battery charging circuit in an example, as shown in fig. 1, a battery charging circuit 2 is respectively connected with an anode and a cathode of a charger 1, a battery 21 to be charged is connected in the battery charging circuit 2, and the charger 1 supplies power to the battery 21 through the battery charging circuit 2.

With continued reference to fig. 1, in the related art, a current limiting module 23 and a sampling module 26 are generally disposed in the battery charging circuit 2, the current limiting module 23 is connected between the negative electrode of the battery 21 and the negative electrode of the charger 1, the sampling module 26 is connected between the output end of the current limiting module 23 and the negative electrode of the charger 1, the sampling module 26 is used for sampling the current of the output end of the current limiting module 23, and the current limiting module 23 adjusts the charging current of the battery according to the sampled current. However, the accuracy of the battery charging circuit in the related art for controlling the charging current of the battery is low.

The technical content provided by the application aims to solve the technical problems of the related technology. The circuit can improve the accuracy of the charging circuit in regulating and controlling the charging current of the battery.

The technical scheme of the present application and the technical scheme of the present application are described in detail below with specific examples. The following embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. In the description of the present application, the terms are to be construed broadly in the art, unless explicitly stated or defined otherwise. Embodiments of the present application will be described below with reference to the accompanying drawings.

Example 1

Fig. 2 is a schematic structural diagram of a battery charging circuit according to an embodiment of the present application, and as shown in fig. 2, the battery charging circuit provided in this embodiment includes:

a first charging port 24;

a second charging port 25;

a battery 21, the positive electrode of the battery 21 being connected to the first charging port 24;

the sampling control module 22, the sampling control module 22 is connected with the negative electrode of the battery 21, the sampling control module 22 is used for sampling the current flowing through the battery 21 and generating a driving signal according to the current flowing through the battery 21;

the current limiting module 23, the current limiting module 23 is connected with the sampling control module 22 and the second charging port 25, and the current limiting module 23 is used for regulating and controlling the charging current of the battery 21 according to the driving signal.

In this embodiment, the first charging port 24 and the second charging port 25 are used as an input port and an output port of the charging circuit, and in practical application, the first charging port 24 may be connected to an anode of the charger, and the second charging port 25 may be connected to a cathode of the charger. Of course, the first charging port 24 and the second charging port 25 may also be connected to the mains. In this embodiment, the battery 21 is charged based on the power supply signals provided by the first charging port 24 and the second charging port 25. For convenience of explanation, the following examples will be given by taking the power supply signal provided by the charger. The charger and the charging circuit can be connected in a detachable mode or in a fixed mode.

In the related art, the sampling module 26 is connected between the output end of the current limiting module 23 and the second charging port 25, and the current of the output end of the current limiting module 23 is unequal to the charging current of the battery 21 due to the influence of the structure of the current limiting module 23 or noise, so that the current limiting module 23 cannot accurately regulate the charging current according to the sampled current. In this embodiment, the sampling control module 22 is connected between the negative electrode of the battery 21 and the current limiting module 23, so that the current collected by the sampling control module 22 is consistent with the charging current of the battery 21, and the accuracy of the charging circuit in regulating and controlling the charging current of the battery 21 can be improved.

In addition, in practical applications, the battery is generally managed by a battery management system (Battery management system, abbreviated as BMS), and in the management process, the BMS needs to obtain the current state of the battery at any time, and therefore, a main circuit sampling unit is also connected in series at the negative electrode of the battery 21 to obtain the current of the battery in the charging and discharging processes. Therefore, in the present embodiment, the main loop sampling unit can directly sample, so that the use of the detection element can be reduced, and the cost can be reduced.

In practical applications, the current limiting module 23 is used for realizing a current limiting function, i.e. a module for ensuring constant charging current. As an embodiment, the current limiting module 23 may be a BOOST topology circuit, and control over the charging current is implemented based on the BOOST topology circuit. For specific structure, reference is made to the related art.

As another implementation, fig. 3 is a schematic structural diagram of another battery charging circuit according to the first embodiment of the present application, and as shown in fig. 3, the current limiting module 23 may include:

the transformer T1, the transformer T1 includes primary winding and secondary winding, the input end of the primary winding is connected with sampling control module 22; the output end of the secondary winding is connected with the second charging port 25 and grounded;

the control end of the first switching element Q1 is connected with the sampling control module 22, one end of the first switching element Q1 is connected with the output end of the primary winding, and the other end of the first switching element Q1 is connected with the second charging port 25 and grounded;

one end of the first capacitor C1 is connected with the other end of the sampling control module 22 and the input end of the primary winding, and the other end of the first capacitor C1 is grounded;

the positive electrode of the first diode D1 is connected to the output end of the secondary winding, and the negative electrode of the first diode D1 is connected to the first charging port 24 and the positive electrode of the battery 21.

In practical application, the charging current refers to an effective average value over a period. During constant current charging of the battery 21, control of the charging current is mainly achieved by switching of the first switching element Q1. The charging process can thus be divided into two phases.

With continued reference to fig. 3, the first phase: when the first switching element Q1 is turned on, the first capacitor C1 discharges, and it should be noted that the first capacitor C1 is fully charged before the constant current charging is entered. The first charging port 24 receives the power supply signal, a current is generated in the charging circuit, and the current flows through the battery 21, the primary winding of the transformer T1 and the first switching element Q1 in sequence, and then returns to the grounded second charging port 222, when the first switching element Q1 is turned on, the primary winding of the transformer T1 generates an induced electromotive force, and since the primary winding and the secondary winding are opposite in terms of their same-name ends, the secondary winding of the transformer T1 generates a current opposite to the first diode D1, and thus the circuit where the secondary winding is located is not turned on, and thus, at this stage, the first charging port 24 receives the power supply signal provided by the charger 1 to charge the battery 21.

With continued reference to fig. 3, the second phase: when the first switching element Q1 is turned off, the first capacitor C1 is charged, the primary winding of the transformer T1 generates a reverse induced electromotive force, the secondary winding of the transformer T1 generates a clockwise induced current, the first diode D1 is turned on, the generated induced current flows to the positive electrode of the battery 21, and then sequentially flows through the battery 21 and the first capacitor C1 (the first capacitor C1 is in a charged state, the first capacitor C1 is turned on), and returns to the second charging port 25, so that the induced electromotive force generated by the secondary winding of the transformer T1 and the power supply signal provided by the charger 1 in the second stage charge the battery 21 together.

It can be understood that the longer the first switching element Q1 is turned on, the larger the induced electromotive force generated by the secondary side of the transformer T1, the larger the instantaneous current in the second phase, and the larger the effective average value of the charging current. Conversely, the shorter the time that the first switching element Q1 is turned on, the smaller the effective average value of the charging current. Thus, the control of the charging current can be achieved by controlling the duty cycle of the switching element Q1.

In addition, in the present embodiment, as also seen in the related art, if the sampling control module 22 is connected between the first charging port 24 and the first switching element Q1, the current flowing from the first switching element Q1 is sampled, and in this case, the current flowing from the first switching element Q1 cannot be kept equal to the charging current. Therefore, the charging current cannot be accurately regulated and controlled based on the sampling current in the related art.

In this embodiment, the current limiting module includes a transformer and a first diode, and the charging voltage of the battery can be controlled by controlling the turns ratio of the primary side and the secondary side of the transformer, instead of only adjusting the switching frequency of the first switching element, in addition, the voltage adjusting range of the first switching element is limited, and in this embodiment, the voltage adjusting range of the transformer is larger, so that the application range of the charging circuit is larger.

As an example, the transformer T1 may be a flat plate transformer. Because the flat-plate transformer is formed by stacking windings or copper sheets on a planar high-frequency iron core to form a magnetic loop of the transformer, the design has low direct-current copper resistance, low leakage inductance and distributed capacitance. And because the magnetic core has good shielding property, radio frequency interference can be restrained, and compared with the traditional transformer, the transformer has better performance and smaller structure.

Optionally, with continued reference to fig. 3, the first capacitor C1 may also perform a filtering function in addition to the current regulation function of the limiting module, so that, to improve the filtering reliability, the limiting module 23 may include a plurality of first capacitors C1, such as 3 first capacitors C1 in fig. 3.

Optionally, with continued reference to fig. 3, the current limiting module 23 may further include:

one end of the third capacitor C3 is connected with the cathode of the first diode D1, and the other end of the third capacitor C3 is connected with the second charging port 25;

the positive electrode of the third diode D3 is connected with the negative electrode of the first diode D1 and the positive electrode of the third diode D3, the negative electrode of the third diode D3 is connected with the first port,

the third capacitor C3 is a filter capacitor, and is used for reducing interference of noise and other factors on a circuit around which the secondary side of the transformer T1 is located, and the third diode D3 is used for preventing the power supply signal received by the first charging port 24 from directly flowing to the second charging port 25 when the third capacitor C3 is charged, so as to avoid short circuit of the charger.

To further improve accuracy of the sampled current, in one example, fig. 4 is a schematic structural diagram of a battery charging circuit according to a first embodiment of the present application, and as shown in fig. 4, the sampling control module 22 includes:

the sampling unit 221, one end of the sampling unit 221 is connected with the negative electrode of the battery 21, and the sampling unit 221 is used for collecting the current flowing through the battery 21;

the control unit 222, one end of the control unit 222 is connected with the other end of the sampling unit 221, the other end of the control unit 222 is connected with the control end of the first switching element Q1, and the control unit 222 is configured to generate a driving signal for controlling the first switching element Q1 to be turned on and off according to the current flowing through the battery 21.

In this example, the sampling unit 221 is configured to sample the current flowing through the battery 21, and in practical application, the sampling unit 221 may also convert the current into a voltage signal and send the voltage signal to the control unit 222. The control unit 222 generates a driving signal according to the sampled voltage signal to control the on/off of the first switching element Q1, where the driving signal may be a PWM signal, and the current charging current may be regulated by adjusting the duty ratio of PWM.

As an example, with continued reference to fig. 4, the sampling unit 221 includes:

the sampling resistor R0, one end of the sampling resistor R0 is connected with the negative electrode of the battery 21, and the other end of the sampling resistor R0 is connected with the current limiting module 23;

the non-inverting input end of the first operational amplifier U1 is connected to one end of the sampling resistor R0, the inverting input end of the first operational amplifier U1 is connected to the other end of the sampling resistor R0, and the output end of the first operational amplifier U1 is connected to the control unit 222.

In this example, the sampling resistor R0 is a resistor with a smaller resistance value, the sampling resistor R0 is connected in series with the battery 21, and the first operational amplifier U1 is configured to collect voltages at two ends of the sampling resistor R0, obtain a sampling current through operation, convert the sampling current into a corresponding voltage signal through a predetermined amplification operation algorithm, and transmit the voltage signal to the control unit 222. The sampling unit 221 provided according to the present example can accurately sample the current flowing through the battery 21.

In practical application, since the resistance value of the sampling resistor R0 is very small, even if noise is very small, the operation result is greatly affected after the operation of the first operational amplifier U1, so that the detection result is distorted.

In this further example, fig. 5 is a schematic structural diagram of a further battery charging circuit provided in the first embodiment of the present application, and as shown in fig. 5, the sampling unit 221 further includes:

the first resistor R1, one end of the first resistor R1 is connected with the output end of the first operational amplifier U1;

one end of the second capacitor C2 is connected with the output end of the first operational amplifier U1 and one end of the first resistor R1;

and the non-inverting input end of the second operational amplifier U2 is connected with the other end of the first resistor R1, the inverting input end of the second operational amplifier U2 is connected with the other end of the second capacitor C2, and the output end of the second operational amplifier U2 is connected with the control unit 222.

In this example, the second operational amplifier U2, the first resistor R1 and the second capacitor C2 form a second-order active filter circuit, which is configured to filter the noise signal collected in the first operational amplifier U1, so as to avoid distortion of the collected signal, thereby improving accuracy of the signal collected by the sampling unit 221.

Optionally, a second diode D2, one end of the second diode D2 is connected to the output end of the second operational amplifier U2 and the control unit 222, and the other end of the second diode D2 is grounded. In practical application, when the battery 21 is discharged, the output end of the second operational amplifier U2 may output a negative voltage, which may damage the control unit 222, and in this embodiment, the second diode D2 is provided, and the second diode D2 clamps the negative voltage of the output of the second operational amplifier U2, so that the negative voltage is prevented from being too low, resulting in damage to the control unit.

Optionally, with continued reference to fig. 5, the sampling unit 221 further includes a fourth capacitor C4, where one end of the fourth capacitor C4 is connected to the other end of the first resistor R1 and the co-directional input end of the second operational amplifier U2, and the other end of the fourth capacitor C4 is grounded.

Optionally, with continued reference to fig. 5, the control unit 320 may include:

the input end of the micro control unit (Micro Control Unit, abbreviated as MCU) is connected to the output end of the first operational amplifier U1, and the output end of the micro control unit 222 is connected to the control end of the first switching element Q1.

The MCU can be based on an algorithm in written software, and outputs a corresponding driving signal by comparing an input signal with a reference value, and the MCU can realize on-line regulation and control of the reference value, so that different charging currents can be regulated and controlled, and the application range of the battery charging circuit is improved.

On the basis of the above example, as an implementation manner, fig. 6 is a schematic structural diagram of still another battery charging circuit provided in the first embodiment of the present application, and as shown in fig. 6, the control unit 222 further includes:

the control end of the second switching element Q2 is connected with the output end of the micro-control unit 222, one end of the second switching element Q2 is grounded, and the ground at one end of the second switching element Q2 is different from the ground at the current module;

the photoelectric coupler U3, the primary side input end of the photoelectric coupler U3 receives a first power supply signal, the primary side output end of the photoelectric coupler U3 is connected with the other end of the second switching element Q2, the secondary side input end of the photoelectric coupler U3 is connected with a second power supply signal, the first output end of the secondary side of the photoelectric coupler U3 is connected with the control end of the first switching element Q1, and the second output end of the secondary side of the photoelectric coupler U3 is grounded;

the photo-coupler U3 is configured to output a first level for controlling the first switching element Q1 to be turned on at a first output end of the photo-coupler U3 when the second switching element Q2 is turned on, and output a second level for controlling the first switching element Q1 to be turned off at a first output end of the photo-coupler U3 when the second switching element Q2 is turned off.

Wherein the photo-coupler may be a driving type photo-coupler, as an example, with continued reference to fig. 7, the photo-coupler U3 may include a light emitting diode, a photoresistor, a POMS tube, and an NMOS tube;

the anode of the light-emitting diode receives the first power supply signal, and the cathode of the light-emitting diode is connected with the other end of the second switch element; one end of the photoresistor receives a second power supply signal, and the other end of the photoresistor is connected with a second charging port; the grid electrode of the PMOS tube is connected with the photoresistor, the source electrode of the PMOS tube receives the second power supply signal, and the drain electrode of the PMOS tube is connected with the control end of the first switching element; the grid electrode of the NMOS tube is connected with the photoresistor, the source electrode of the NMOS tube is connected with the second charging port and grounded, and the drain electrode of the NMOS tube is connected with the control end of the first switching element. When the light emitting diode emits light, a circuit in which the photoresistor is positioned is conducted, the grid electrodes of the PMOS tube and the NMOS tube receive high level, the PMOS tube is conducted, the NMOS tube is disconnected, and the first output end outputs high level; on the contrary, when the light emitting diode does not emit light, the circuit where the photoresistor is located is not conducted, the grid electrodes of the PMOS tube and the NMOS tube receive low level, the PMOS tube is conducted, the NMOS tube is disconnected, and the first output end outputs low level.

The working principle of this example is: taking the driving signal as a PWM signal and the first switching element Q1 and the second switching element Q2 as NMOS tubes as examples after the MCU outputs the driving signal, the PWM signal is connected to the second switching element Q2, when the PWM signal is at a high level, the second switching element Q2 is conducted, the light emitting diode in the photoelectric coupler U3 lightens, the PMOS tube in the photoelectric coupler U3 is conducted, the point A of the first output end outputs a high level, and the first switching element Q1 is conducted; conversely, when the PWM signal is at a low level, the second switching element Q2 is turned off, the light emitting diode in the photo coupler U3 does not emit light, the NMOS tube in the photo coupler U3 is turned on, the first input terminal a of the photo coupler U3 outputs a low level, and the first switching element Q1 is turned off, thereby realizing regulation and control of the charging current.

In this embodiment, the ground of the sampling control module is different from the ground of the second charging port, and the transmission of signals at two ends is realized through the photoelectric coupler, so that the isolation of two ends is further realized, and the influence of the switching noise of the first switching element on the sampling control module is reduced.

In the battery charging circuit provided by the embodiment, the sampling control module is connected with the negative electrode of the battery, the current flowing through the battery is directly sampled, and the current limiting module adjusts the current charging current according to the sampled current so as to realize the regulation and control of the charging current of electricity. Compared with the related art, the sampling control module in the embodiment is connected between the negative electrode of the battery and the current limiting module, so that the current collected by the sampling control module is consistent with the charging current of the battery, and the accuracy of the charging circuit in regulating and controlling the charging current of the battery can be improved.

Example two

In practical application, a situation that the first charging port is reversely connected to the second charging port, that is, the first charging port is connected to the negative electrode of the charger, and the second charging port is connected to the positive electrode of the power supply, is often occurred, referring to fig. 1, if in the reversely connected situation, the current flows to the first charging port 24 through the second charging port 25, the secondary winding of the transformer T1 and the first diode D1, so that the positive electrode and the negative electrode of the charger 1 are shorted, and the charger is damaged.

For this reason, fig. 7 is a schematic structural diagram of a battery charging circuit according to the second embodiment of the present application, and as shown in fig. 7, on the basis of the foregoing embodiment, the battery charging circuit according to the present embodiment further includes:

the reverse connection preventing module 27, one end of the reverse connection preventing module 27 is connected with the first charging port 24, and the other end of the reverse connection preventing module 27 is connected with the cathode of the first diode D1;

in this embodiment, the reverse connection preventing module 27 is configured to establish a connection between the first charging port 24 and the first diode D1 when the first charging port 24 is connected to the positive pole of the charger, and disconnect the connection between the first charging port 24 and the first diode D1 when the first charging port 24 is connected to the negative pole of the charger 1, so as to avoid a short circuit between the positive pole and the negative pole of the charger when the battery charging circuit is reversely connected to the charger, thereby further improving the safety of battery charging.

In one example, fig. 8 is a schematic structural diagram of another battery charging circuit according to the second embodiment of the present application, and as shown in fig. 8, the anti-reverse connection module 27 includes:

the voltage division unit 271, the voltage division unit 271 is connected with the first charging port 24 and the second charging port 25, the voltage division unit 271 is configured to output a first level when the first charging port 24 is connected to the positive electrode of the charger 1, and output a second level when the first charging port 24 is connected to the negative electrode of the charger 1;

a fourth switching element Q4, a control end of the fourth switching element Q4 is connected to the voltage dividing unit 271, and one end of the fourth switching element Q4 is grounded; the fourth switching element Q4 is configured to be turned on when the voltage division unit 271 outputs the first level and turned off when the voltage division unit 271 outputs the second level;

and a third switching element Q3, a control terminal of the third switching element Q3 is connected to the other terminal of the fourth switching element Q4, one terminal of the third switching element Q3 is connected to the first charging port 24, the other terminal of the third switching element Q3 is connected to the negative electrode of the first diode D1, and the third switching element Q3 is configured to be turned on when the fourth switching element Q4 is turned on and turned off when the fourth switching element Q4 is turned off.

The third switching element Q3 and the fourth switching element Q4 may be transistors or field effect transistors, as long as they are switching elements capable of controlling the on/off.

The working principle of the present solution will be exemplarily described below with reference to specific examples: taking the third switching element Q3 as a PMOS transistor and the fourth switching element Q4 as an NMOS transistor as an example, with continued reference to fig. 8, when the first charging port 24 is connected to the positive electrode of the charger 1, the voltage dividing circuit outputs a high level, the gate of the fourth switching element Q4 (NMOS transistor) receives the high level, reaching the turn-on voltage, and the fourth switching element Q4 is turned on; the gate of the third switching element Q3 is grounded, receives a low level, the third switching element Q3 is turned on, and the first charging port 24 is connected to the first diode D1. When the first charging port 24 is connected to the negative electrode of the charger 1 and the second charging port 25 is connected to the positive electrode of the charger 1, the voltage dividing unit 271 outputs a low level, the fourth switching element Q4 is turned off, the third switching element Q3 is turned off, and the first charging port 24 is turned off from the first diode D1.

In this example, the voltage dividing unit outputs a corresponding level based on a power supply signal provided by the charger, and when the charger is connected, the voltage dividing unit is further configured to adjust a higher voltage provided by the power supply to be within an allowable voltage of the control end of the fourth switching element, so that damage of the high voltage to the control end of the fourth switching element is avoided.

As an embodiment, with continued reference to fig. 8, the voltage dividing unit 271 includes:

the emitter of the first triode V1 is connected with the control end of the fourth switching element Q4, and the collector of the first triode V1 is connected with the first charging port 24;

the emitter of the second triode V2 is connected with the base electrode of the first triode V1, and the emitter of the second triode V2 is connected with the first charging port 24;

the positive electrode of the voltage stabilizing diode D4 is connected with the second charging port 25, and the negative electrode of the voltage stabilizing diode D4 is connected with the base electrode of the second triode V2;

and one end of the second resistor R2 is connected with the grid electrode of the first triode V1 and the emitter electrode of the second triode V2, and the other end of the second resistor R2 is connected with the positive electrode of the zener diode D4 and the second diode of the charger 1 and the second charging port 25.

The working principle will be exemplarily described in connection with the following specific scenarios: with continued reference to fig. 8, the first diode D1 and the second diode D2 are PN diodes as examples. When the first charging port 24 is connected with the positive electrode of the charger 1 and the second charging port 25 is connected with the negative electrode of the charger 1, the first charging port 24 is positive voltage, the second charging port 25 is zero, at this time, the first triode V1 and the second triode V2 are turned on, the zener diode D4 is connected in parallel with the second resistor R2, the voltage of the base electrode of the first triode V1 is regulated to a predetermined value, the predetermined value can be set according to the working voltages of the fourth switching element Q4, the first triode V1 and the second triode V2, the fourth switching element Q4 receives a high level reaching the turn-on voltage, and the fourth switching element Q4 is turned on, thereby realizing the turn-on of the third switching element Q3. When the first charging port 24 and the second charging port 25 are reversely connected, the voltage of the first charging port 24 is zero, and thus the fourth switching element Q4 receives a low level, the fourth switching element Q4 is turned off, and the third switching element Q3 is turned off, thereby disconnecting the first charging port 24 and the first diode D1.

Optionally, the voltage dividing unit 271 may further include:

and a fifth capacitor C5, one end of the fifth capacitor C5 is connected to the control end of the fourth switching element Q4, and the other end of the fifth capacitor C5 is connected to the second charging port 25. The fifth capacitor C5 is a filter capacitor.

In connection with the above example where the control unit 222 includes a photo coupler U3, as an embodiment, with continued reference to fig. 8, the input of the secondary side of the photo coupler U3 is connected to the emitter of the first transistor V1. That is, the voltage dividing unit 271 is also configured to supply the first level to the photo coupler U3.

The power supply circuit provided by the embodiment comprises the reverse connection prevention module, wherein the reverse connection prevention module is used for establishing connection between the first charging port and the first diode when the first charging port is connected with the positive electrode of the charger, and disconnecting connection between the first charging port and the first diode when the first charging port is connected with the negative electrode of the charger, so that the short circuit of the positive electrode and the negative electrode of the charger is avoided when the battery charging circuit is reversely connected with the charger, and the safety of battery charging is further improved.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the utility model disclosed herein. This application is intended to cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the application pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

It is to be understood that the present application is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims (11)

1. A battery charging circuit, comprising:

a first charging port;

a second charging port;

the positive electrode of the battery is connected with the first charging port;

the sampling control module is connected with the negative electrode of the battery and is used for sampling the current flowing through the battery and generating a driving signal according to the current flowing through the battery;

the current limiting module is connected with the sampling control module and the second charging port and is used for regulating and controlling the charging current of the battery according to the driving signal.

2. The battery charging circuit of claim 1, wherein the current limiting module comprises:

the transformer comprises a primary winding and a secondary winding, and the input end of the primary winding is connected with the sampling control module; the output end of the secondary winding is connected with the second charging port and grounded;

the control end of the first switching element is connected with the sampling control module, one end of the first switching element is connected with the output end of the primary winding, and the other end of the first switching element is connected with the second charging port and grounded;

one end of the first capacitor is connected with the other end of the sampling control module and the input end of the primary winding, and the other end of the first capacitor is grounded;

the positive electrode of the first diode is connected with the output end of the secondary winding, and the negative electrode of the first diode is connected with the first charging port and the positive electrode of the battery.

3. The battery charging circuit of claim 2, wherein the sampling control module comprises:

the sampling unit is used for collecting current flowing through the battery;

and one end of the control unit is connected with the other end of the sampling unit, the other end of the control unit is connected with the control end of the first switching element, and the control unit is used for generating a driving signal for controlling the first switching element to be switched on and off according to the current flowing through the battery.

4. The battery charging circuit of claim 3, wherein said sampling unit comprises:

one end of the sampling resistor is connected with the negative electrode of the battery, and the other end of the sampling resistor is connected with the current limiting module;

the non-inverting input end of the first operational amplifier is connected with one end of the sampling resistor, the inverting input end of the first operational amplifier is connected with the other end of the sampling resistor, and the output end of the first operational amplifier is connected with the control unit.

5. The battery charging circuit of claim 4, wherein said sampling unit further comprises:

one end of the first resistor is connected with the output end of the first operational amplifier;

one end of the second capacitor is connected with the output end of the first operational amplifier and one end of the first resistor;

the non-inverting input end of the second operational amplifier is connected with the other end of the first resistor, the inverting input end of the second operational amplifier is connected with the other end of the second capacitor, and the output end of the second operational amplifier is connected with the control unit;

and one end of the second diode is connected with the output end of the second operational amplifier and the control unit, and the other end of the second diode is grounded.

6. The battery charging circuit of claim 4, wherein said control unit comprises:

the input end of the micro control unit is connected with the output end of the first operational amplifier, and the output end of the micro control unit is connected with the control end of the first switching element.

7. The battery charging circuit of claim 6, wherein said control unit further comprises:

the control end of the second switching element is connected with the output end of the micro control unit, one end of the second switching element is grounded, and the ground of one end of the second switching element is different from the ground of the current module;

the primary side input end of the photoelectric coupler receives a first power supply signal, the primary side output end of the photoelectric coupler is connected with the other end of the second switching element, the secondary side input end of the photoelectric coupler receives a second power supply signal, the first output end of the secondary side of the photoelectric coupler is connected with the control end of the first switching element, and the second output end of the secondary side of the photoelectric coupler is grounded;

the first output end of the photoelectric coupler outputs a first level for controlling the first switching element to be switched on when the second switching element is switched on, and outputs a second level for controlling the first switching element to be switched off when the second switching element is switched off.

8. The battery charging circuit of claim 2, wherein the battery charging circuit further comprises:

one end of the reverse connection preventing module is connected with the first charging port, and the other end of the reverse connection preventing module is connected with the negative electrode of the first diode;

the reverse connection prevention module is used for establishing connection between the first charging port and the first diode when the first charging port is connected with the positive electrode of the charger, and disconnecting connection between the first charging port and the first diode when the first charging port is connected with the negative electrode of the charger.

9. The battery charging circuit of claim 8, wherein said anti-reverse module comprises:

the voltage division unit is connected with the first charging port and the second charging port and is used for outputting a first level when the first charging port is connected with the positive electrode of the charger and outputting a second level when the first charging port is connected with the negative electrode of the charger;

the control end of the fourth switching element is connected with the voltage dividing unit, and one end of the fourth switching element is grounded; the fourth switching element is used for being conducted when the voltage division unit outputs a first level and being disconnected when the voltage division unit outputs a second level;

the control end of the third switching element is connected with the other end of the fourth switching element, one end of the third switching element is connected with the first charging port, the other end of the third switching element is connected with the negative electrode of the first diode, and the third switching element is used for being conducted when the fourth switching element is conducted and disconnected when the fourth switching element is disconnected.

10. The battery charging circuit of claim 9, wherein the voltage dividing unit comprises:

the emitter of the first triode is connected with the control end of the fourth switching element, and the collector of the first triode is connected with the first charging port;

an emitter of the second triode is connected with a base electrode of the first triode, and an emitter of the second triode is connected with the first charging port;

the anode of the voltage stabilizing diode is connected with the second charging port, and the cathode of the voltage stabilizing diode is connected with the base electrode of the second triode;

and one end of the second resistor is connected with the grid electrode of the first triode and the emitter electrode of the second triode, and the other end of the second resistor is connected with the anode of the voltage stabilizing diode, the second diode of the charger and the second charging port.

11. The battery charging circuit of any one of claims 2-10, wherein the transformer is a planar transformer.