Photoelectric induction LED lamp control circuit

Abstract

The utility model relates to the technical field of LED control, and discloses a photoelectric induction LED lamp control circuit which is low in static power consumption and reliable, the photoelectric induction LED lamp control circuit comprises a main control circuit (200) and an LED drive circuit (300), a signal input end of a switch circuit (202) is connected with a signal output end of a main controller (U3) and is used for receiving a control signal; the LED driving circuit (300) is used for receiving a PWM signal input by the main controller (U3), and the PWM signal is used for triggering the LED driving circuit (300) to work so as to control the LED module to be conducted.

Description

Technical Field

[0001] The utility model relates to the technical field of LED control, and more specifically, to a photoelectric induction LED lamp control circuit. Background Art

[0002] At present, indoor induction lamps on the market usually adopt PIR (pyroelectric infrared sensor) circuits. Such products usually have a large induction range (3 - 5 meters) and require AC power supply. The large induction range of PIR products leads to easy mis-triggering of the products, which affects the product life and increases power consumption. Another type of photoelectric induction lamp circuit has a relatively large static power consumption (more than 10 mA) due to the use of a functional integrated circuit IC, and the lighting time cannot be adjusted.

[0003] Therefore, how to reduce the static power consumption during the extinguished state to extend the battery life has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a photoelectric induction LED lamp control circuit with relatively low static power consumption and reliability, aiming at the defect that the existing photoelectric induction lamp circuit has a relatively large static power consumption due to the use of a functional integrated circuit IC.

[0005] The technical solution adopted by the utility model to solve its technical problem is to construct a photoelectric induction LED lamp control circuit, which includes:

[0006] A main control circuit, which is configured in the control circuit; wherein,

[0007] The main control circuit includes at least an induction circuit, a switch circuit and a main controller,

[0008] The induction circuit is used to receive an induction signal input from the outside,

[0009] One end of the switch circuit is used to receive the voltage signal of the battery module,

[0010] The signal input end of the switch circuit is connected to a signal output end of the main controller for receiving a control signal;

[0011] An LED driving circuit, whose input end is connected to another signal output end of the main controller for receiving the PWM signal input by the main controller. The PWM signal is used to trigger the LED driving circuit to work to control the conduction of the LED module.

[0012] In some embodiments, the induction circuit includes a reflective photoelectric switch,

[0013] The primary side of the reflective photoelectric switch is used to emit a light beam signal,

[0014] The secondary side of the reflective optoelectronic switch is used to receive the beam signal, wherein,

[0015] The output end of the secondary side of the reflective optoelectronic switch is connected to one end of the switch circuit.

[0016] When the output of the reflective optoelectronic switch is at a low level, the switch circuit is controlled to be turned off;

[0017] When the output of the reflective optoelectronic switch is at a high level, the switch circuit is controlled to be turned on, and the voltage signal is input to the main controller.

[0018] In some embodiments, the switch circuit includes a first MOS transistor and a first triode.

[0019] The base of the first triode is connected to the signal output end of the main controller.

[0020] The collector of the first triode is connected to the gate of the first MOS transistor through a ninth resistor.

[0021] The source of the first MOS transistor is connected to the positive pole of the battery module.

[0022] The drain of the first MOS transistor is connected to the power supply end of the main controller.

[0023] The emitter of the first triode is connected to the common end.

[0024] In some embodiments, the LED driving circuit includes at least one linear buck driver.

[0025] The signal input end of the linear buck driver is connected to the signal output end of the main controller for receiving the PWM signal.

[0026] One output end of the linear buck driver is connected to the negative pole of the LED module.

[0027] In some embodiments, the main control circuit further includes a low-voltage protection circuit.

[0028] The input end of the low-voltage protection circuit is connected to the output end of the switch circuit for receiving the voltage signal.

[0029] The output end of the low-voltage protection circuit is connected to the voltage feedback end of the main controller.

[0030] In some embodiments, the low-voltage protection circuit includes a tenth resistor and an eleventh resistor connected in series.

[0031] One end of the tenth resistor and the eleventh resistor is connected to the voltage feedback end of the main controller.

[0032] The other end of the tenth resistor is connected to the output end of the switch circuit.

[0033] The other end of the eleventh resistor is connected to the common end.

[0034] In some embodiments, a timing circuit is further included.

[0035] The input end of the timing circuit is connected to the output end of the switch circuit for receiving the voltage signal.

[0036] The output end of the timing circuit is connected to the timing end of the main controller for receiving the timing signal fed back by the timing circuit.

[0037] The main controller outputs the PWM signal according to the fed-back timing signal to adjust the lighting time of the LED module.

[0038] In some embodiments, a battery charging circuit is further included.

[0039] The input end of the battery charging circuit is connected to an external power supply terminal.

[0040] The output end of the battery charging circuit is connected to the positive pole of the battery module.

[0041] In the optoelectronic induction LED lamp control circuit of the present utility model, a main control circuit and an LED driving circuit are included. Among them, the induction circuit is used to receive an externally input induction signal to control the output of a control signal. One input end of the switch circuit is connected to the signal output end of the main controller for receiving the control signal. The LED driving circuit is used to receive the PWM signal input by the main controller, and the PWM signal is used to trigger the operation of the LED driving circuit to control the conduction of the LED module. Compared with the prior art, by using the induction circuit to receive the externally input induction signal to control the power supply input to the main controller, so that the main controller inputs the PWM signal to the LED driving circuit, thereby controlling the operation of the LED driving circuit and turning on the LED module controlled, it can effectively solve the problem of large static power consumption of the optoelectronic induction type lamp circuit due to the use of a functional integrated circuit IC. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present utility model will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0043] Figure 1a is the circuit schematic diagram of an embodiment of the battery charging circuit provided by the present utility model;

[0044] Figure 1b is the circuit schematic diagram of an embodiment of the main control circuit provided by the present utility model;

[0045] Figure 1c This is the circuit schematic diagram of an embodiment of the LED driving circuit provided by the present utility model;

[0046] Figure 1d This is the circuit schematic diagram of an embodiment of the timing circuit provided by the present utility model. Specific embodiments

[0047] For a clearer understanding of the technical features, objectives, and effects of the present utility model, the specific embodiments of the present utility model will now be described in detail with reference to the accompanying drawings.

[0048] As Figures 1a - 1d shown, in the first embodiment of the photoelectric induction LED lamp control circuit of the present utility model, the photoelectric induction LED lamp control circuit includes a battery charging circuit 100, a main control circuit 200, an LED driving circuit 300, and a timing circuit 400.

[0049] Among them, the battery charging circuit 100 is used to charge the battery module (corresponding to BAT);

[0050] The main control circuit 200 has the functions of arithmetic processing, outputting PWM signals, control signals, low-voltage protection, and controlling the working state of the LED module (corresponding to LED1-LED8);

[0051] The LED driving circuit 300 is used to receive the PWM signal input by the main control circuit 200 to control the working state and duration of the LED module (corresponding to LED1-LED8);

[0052] The timing circuit 400 outputs a voltage signal (varying between 0.1V and 2.1V) according to the resistance value of the variable resistor VR1.

[0053] Specifically, the main control circuit 200 is configured in the control circuit and is used to receive the power signal input by the battery module (corresponding to BAT) to provide power for its operation or standby; among them,

[0054] The main control circuit 200 includes at least one induction circuit 201, a switch circuit 202, and a main controller U3,

[0055] Among them, the induction circuit 201 is used to receive the external input induction signal and control its conduction or cutoff according to the induction signal;

[0056] For example, when the induction circuit 201 is blocked by an object (corresponding to the induction signal), the induction circuit 201 is cutoff,

[0057] When the induction circuit 201 is not blocked by an object (corresponding to the induction signal), the induction circuit 201 is conductive;

[0058] The switch circuit 202 is used to receive the voltage signal input from the battery module (corresponding to BAT) and the control signal (high level or low level) input from the main controller U3;

[0059] When the sensing circuit 201 is not blocked by an object, the sensing circuit 201 is in the cut-off state, and the switch circuit 202 is cut off;

[0060] When the sensing circuit 201 is blocked by an object, the sensing circuit 201 is in the conducting state, the main controller U3 is powered on, the output control signal is high level, and the switch circuit 202 is controlled to conduct;

[0061] A signal output terminal (corresponding to pin 2) of the main controller U3 is connected to one end of the switch circuit 202 to output a control signal to the switch circuit 202,

[0062] The power supply terminal (corresponding to pin 21) of the main controller U3 is used to receive the voltage signal input from the battery module (corresponding to BAT) when the switch circuit 202 is conducting;

[0063] Specifically, the sensing circuit 201 is used to receive the external input sensing signal and control its conduction or cut-off according to the sensing signal;

[0064] When the sensing circuit 201 is blocked by an object (a short block is sufficient, such as within 1 second), the sensing circuit 201 is in the conducting state, the main controller U3 is powered on, and the output control signal is high level;

[0065] One end of the switch circuit 202 is connected to the output terminal of the battery module (corresponding to BAT) to receive the voltage signal output by the battery module (corresponding to BAT),

[0066] The signal input terminal of the switch circuit 202 is connected to a signal output terminal (corresponding to pin 2) of the main controller U3 to receive the control signal output by the main controller U3,

[0067] When the input control signal is low level, the switch circuit 202 is in the cut-off state;

[0068] When the input control signal is high level, the switch circuit 202 is controlled to conduct, and there is a current signal at its output terminal (corresponding to VCC), and the main controller U3 is powered, so that it is in the standby or working state;

[0069] A signal output terminal (corresponding to pin 2) of the main controller U3 is connected to the signal input terminal of the switch circuit 202 to receive the control signal to trigger the switch circuit 202 to work;

[0070] Further, the input end of the LED driving circuit 300 is connected to another signal output end (corresponding to pin 11) of the main controller U3, which is used to receive the PWM signal input by the main controller U3. This PWM signal is used to trigger the operation of the LED driving circuit 300 to control the conduction of the LED module (corresponding to LED1-LED8).

[0071] When the induction circuit 201 is not blocked by an object, the induction circuit 201 is in a cut-off state, and the switch circuit 202 is turned off, causing the main controller U3 to lose its operating power supply. No PWM signal is output at its signal output end (corresponding to pin 11), and further, the LED driving circuit 300 is controlled to be turned off, and the LED module (corresponding to LED1-LED8) is controlled to be turned off.

[0072] Using this technical solution, the induction circuit 201 is used to receive the externally input induction signal to control the power supply input to the main controller U3. The main controller U3 inputs a control signal to the switch circuit 202, causing the main controller U3 to input a PWM signal to the LED driving circuit 300, thereby controlling the operation of the LED driving circuit 300, and the LED module is controlled to be lit, which can effectively solve the problem of large static power consumption of the product due to the use of a functional integrated circuit IC in the circuit of the photoelectric induction type lamp.

[0073] In some embodiments, as Figure 1b shown, the induction circuit 201 includes a reflective photoelectric switch U5, which is used to detect the change in the light intensity it receives;

[0074] Specifically, one end (corresponding to pin 1) of the primary side (corresponding to pins 1 and 2) of the reflective photoelectric switch U5 is connected to the positive pole of the battery module (corresponding to BAT) through the thirty-eighth resistor R38 for emitting a light beam signal,

[0075] One end (corresponding to pin 3) of the secondary side (corresponding to pins 3 and 4) of the reflective photoelectric switch U5 is connected to the positive pole of the battery module (corresponding to BAT) through the thirty-ninth resistor R39 for receiving the light beam signal, where

[0076] The output end (corresponding to pin 4) of the secondary side of the reflective photoelectric switch U5 is connected to one end of the switch circuit 202,

[0077] When the reflective photoelectric switch U5 is not blocked by an object, the output of the main controller U3 is at a low level, and the switch circuit 202 is controlled to be turned off;

[0078] When the reflective photoelectric switch U5 is blocked by an object (a short-term block is sufficient, such as within 1 second), the main controller U3 is powered on, and the output control signal is at a high level, and the switch circuit 202 is controlled to be turned on.

[0079] In some embodiments, as Figure 1bAs shown, the switch circuit 202 includes a first MOS transistor Q1 and a first triode Q6. Among them, the first MOS transistor Q1 is selected as a P-channel MOS transistor, and the first triode Q6 is selected as an NPN-type triode, both of which have the function of a switch.

[0080] Specifically, the base of the first triode Q6 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the output terminal (corresponding to pin 4) of the secondary side of the reflective optoelectronic switch U5.

[0081] The base of the first triode Q6 is connected to the signal output terminal (pin 2) of the main controller U3 through the second diode D2, for receiving the control signal input by the main controller U3.

[0082] The collector of the first triode Q6 is connected to the gate of the first MOS transistor Q1 through the ninth resistor R9.

[0083] The source of the first MOS transistor Q1 is connected to the positive pole of the battery module (corresponding to BAT) through the eighth resistor R8.

[0084] The drain of the first MOS transistor Q1 (corresponding to the VCC terminal) is connected to the power supply terminal (corresponding to the VDD terminal) of the main controller U3 through the fifth diode D5.

[0085] The emitter of the first triode Q6 is connected to the common terminal.

[0086] When the output of the main controller U3 is at a high level, the first triode Q6 is controlled to conduct, the potential of the gate of the first MOS transistor Q1 is pulled down to a low level, controlling its conduction, and the current signal (corresponding to VCC) of the battery module (corresponding to BAT) is output through the source-drain of the first MOS transistor Q1 to form a VCC voltage. This VCC voltage is input to the power supply terminal (corresponding to the VDD terminal) of the main controller U3 through the fifth diode D5, so that the main controller U3 is in a standby or working state to output a PWM signal to the LED driving circuit 300.

[0087] In some embodiments, as Figure 1c shown, the LED driving circuit 300 includes at least one linear buck driver U4, which has the functions of PWM signal processing and current detection.

[0088] Specifically, the signal input terminal (corresponding to the VDD terminal) of the linear buck driver U4 is connected to the signal output terminal (corresponding to pin 11) of the main controller U3 through the thirty-fourth resistor R34, for receiving the PWM signal.

[0089] Among them, the positive poles of the LED modules (corresponding to LED1-LED8) are connected to the drain of the first MOS transistor Q1 (corresponding to the VCC terminal), for receiving the VCC voltage signal.

[0090] One output terminal (corresponding to the LED terminal) of the linear buck driver U4 is connected to the negative electrode of the LED module (corresponding to LED1-LED8).

[0091] When the PWM signal is at a high level, the linear buck driver U4 works, pulling down the negative electrode of the LED module (corresponding to LED1-LED8), so that the VCC voltage signal passes through the LED module (corresponding to LED1-LED8) to the common terminal to control the operation of the LED module (corresponding to LED1-LED8).

[0092] Among them, the current detection terminal (corresponding to the CS terminal) of the linear buck driver U4 is connected to the current feedback terminal (corresponding to pin 16) of the main controller U3 through the thirty-fifth resistor R35, feeding back the current signal when the LED module (corresponding to LED1-LED8) is working to the main controller U3, and it adjusts the duty cycle of the output PWM signal according to the feedback current signal to adjust the brightness of the LED module (corresponding to LED1-LED8).

[0093] In some embodiments, as Figure 1b shown, the main control circuit 200 further includes a low-voltage protection circuit 203, which is used to detect the voltage value of the battery module (corresponding to BAT), perform voltage division processing on this voltage value, and then output it to the main controller U3.

[0094] Specifically, the input terminal of the low-voltage protection circuit 203 is connected to the output terminal (corresponding to the drain of the first MOS transistor Q1) of the switching circuit 202, used to receive the voltage signal (corresponding to VCC), and perform voltage division processing on this voltage signal (corresponding to VCC).

[0095] The output terminal of the low-voltage protection circuit 203 is connected to the voltage feedback terminal (corresponding to pin 14) of the main controller U3, used to receive the voltage signal after voltage division processing. When the voltage signal is lower than the lower protection value (such as 2.8V) of the main controller U3, the main controller U3 stops outputting the PWM signal, controlling the LED module (corresponding to LED1-LED8) to turn off, so as to avoid affecting the service life of the battery module (corresponding to BAT) due to over-discharge.

[0096] In some embodiments, as Figure 1b shown, the low-voltage protection circuit 203 includes a tenth resistor R10 and an eleventh resistor R11 connected in series. Among them, one end of the tenth resistor R10 and the eleventh resistor R11 is connected to the voltage feedback terminal (corresponding to pin 14) of the main controller U3.

[0097] The other end of the tenth resistor R10 is connected to the output terminal (corresponding to the drain of the first MOS transistor Q1) of the switching circuit 202.

[0098] The other end of the eleventh resistor R11 is connected to the common terminal.

[0099] When the voltage of the battery module (corresponding to BAT) used drops to 2.8V, the terminal voltage (power) of the eleventh resistor R11 is about 0.47V (Vpower = VCC * R11 / (R11 + R10)). At this time, the 14th pin of the main controller U3 samples through the ADC, converts it into a digital signal, and makes the 11th pin stop outputting the PWM signal, so that the LED module (corresponding to LED1 - LED8) goes out, avoiding over-discharge of the battery module (corresponding to BAT) and effectively extending the service life of the battery module (corresponding to BAT).

[0100] In some embodiments, as Figure 1d shown, the control circuit further includes a timing circuit 400, wherein,

[0101] The input end (corresponding to VCC) of the timing circuit 400 is connected to the output end (corresponding to the drain of the first MOS transistor Q1) of the switching circuit 202 for receiving a voltage signal,

[0102] The output end (corresponding to the Timr terminal) of the timing circuit 400 is connected to the timing terminal (corresponding to the 15th pin) of the main controller U3 for receiving the timing signal fed back by the timing circuit 400,

[0103] The main controller U3 adjusts the duty cycle of the PWM signal according to the fed-back timing signal to adjust the lighting time of the LED module.

[0104] Among them, the timing circuit 400 includes a variable resistor RV1 and a seventh resistor R7. One end of the variable resistor RV1 and the seventh resistor R7 is connected to the timing terminal (corresponding to the 15th pin) of the main controller U3,

[0105] The other end of the seventh resistor R7 is connected to the drain of the first MOS transistor Q1,

[0106] The other end of the variable resistor RV1 is connected to the common terminal.

[0107] Specifically, by adjusting the variable resistor RV1, the voltage at the "Timer" terminal changes from 0.1V to 2.1V. The timing terminal (corresponding to the 15th pin) of the main controller U3 samples different voltages through the ADC and converts them into digital signals, so as to generate different time output PWM signals corresponding to the 11th pin to the linear buck driver U4, thereby adjusting the lighting time of the LED module (corresponding to LED1 - LED8), which can be divided into 3 minutes / 5 minutes / 10 minutes, etc.

[0108] In some embodiments, as Figure 1a shown, the control circuit further includes a battery charging circuit 100, which is used to charge the battery module (corresponding to BAT);

[0109] Specifically, the input terminal (corresponding to pin 4) of the battery charging circuit 100 is connected to an external power supply terminal.

[0110] The output terminal (corresponding to pin 5) of the battery charging circuit 100 is connected to the positive electrode of the battery module (corresponding to BAT) to charge the battery module (corresponding to BAT).

[0111] When the battery life is exhausted (infinite internal resistance), a conventional mobile phone plug (output DC5V) is used and connected to the USB_IN interface through a Type-C data cable. At this time, the BAT pin of the battery charging controller U1 outputs a charging voltage (3.7 - 4.2V). When the lighting condition is satisfied, the product can work and light up normally; therefore, the normal service life of the product can be maintained for more than 5 years.

[0112] Its working principle is as follows:

[0113] In the standby state, after the main control circuit 200 is connected to the battery module (corresponding to BAT), the primary 2-1 pin of the reflective photoelectric switch is in the state of emitting a light beam signal. Since there is no obstacle to reflect the emitted light beam signal to the reflective photoelectric switch U5, at this time, the 3-4 pins on the secondary side of the reflective photoelectric switch U5 are in the cut-off state, and the first triode Q6 is not conducting, so VCC = 0V, and the main controller U3 is in the stop working state; at this time, only the 2-1 pin on the primary side of the reflective photoelectric switch U5 is consuming power, and the standby current is very low (5mA conduction current);

[0114] During the LED module lighting process, when there is an obstacle (corresponding to the induction signal) passing by the reflective photoelectric switch U5 (such as a human hand / foot part or other obstacles);

[0115] The light beam signal emitted by the primary 2-1 pin of the reflective photoelectric switch U5 is reflected to the 3-4 pins on the secondary side of the reflective photoelectric switch U5. Therefore, the 3-4 pins on the secondary side of the reflective photoelectric switch U5 are conducting, and there is current flowing through, causing the first triode Q6 to conduct. There is a voltage at the VCC terminal (approximately equal to the battery voltage), enabling the main controller U3 to be powered. After startup, a signal output terminal (corresponding to pin 2) of the main controller U3 outputs a high level (3.3V). At the same time, the 11th pin outputs a PWM signal to the VDD pin of the linear buck driver U4, and the linear buck driver U4 is in the working state, pulling the "LED-" pin to a low level state, and the LED module (corresponding to LED1 - LED8) is conducting and in the lighting state.

[0116] The embodiments of the present utility model have been described above in conjunction with the accompanying drawings. However, the present utility model is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present utility model, those of ordinary skill in the art can also make many forms without departing from the purpose of the present utility model and the scope protected by the claims. All of these fall within the protection scope of the present utility model.

Claims

1. A photoelectric sensing LED lamp control circuit, characterized in that: have: A main control circuit is configured in the control circuit; wherein, The main control circuit includes at least a sensing circuit, a switch circuit and a main controller. The sensing circuit is used to receive a sensing signal input from the outside. One end of the switch circuit is used to receive a voltage signal of the battery module. The signal input terminal of the switch circuit is connected to a signal output terminal of the main controller for receiving a control signal; The LED driving circuit has an input end connected to another signal output end of the main controller and is used to receive a PWM signal input by the main controller. The PWM signal is used to trigger the LED driving circuit to operate so as to control the LED module to turn on.

2. The photoelectric sensing LED lamp control circuit according to claim 1, characterized in that: The sensing circuit includes a reflective photoelectric switch, The primary side of the reflective photoelectric switch is used to emit a light beam signal. The secondary side of the reflective photoelectric switch is used to receive a light beam signal, wherein: The output end of the secondary side of the reflective photoelectric switch is connected to one end of the switch circuit. When the reflective photoelectric switch outputs a low level, the switch circuit is controlled to be closed; When the reflective photoelectric switch outputs a high level, the switch circuit is controlled to be turned on, and the voltage signal is input to the main controller.

3. The photoelectric sensing LED lamp control circuit according to claim 2, characterized in that: The switch circuit includes a first MOS tube and a first transistor. The base of the first transistor is connected to the signal output terminal of the main controller. The collector of the first triode is connected to the gate of the first MOS tube through a ninth resistor. The source electrode of the first MOS tube is connected to the positive electrode of the battery module. The drain of the first MOS tube is connected to the power supply terminal of the main controller. The emitter of the first transistor is connected to the common end.

4. The photoelectric induction LED lamp control circuit according to claim 3, characterized in that: The LED driving circuit includes at least one linear buck driver, The signal input terminal of the linear buck driver is connected to the signal output terminal of the main controller for receiving the PWM signal. An output end of the linear buck driver is connected to the cathode of the LED module.

5. The photoelectric sensing LED lamp control circuit according to claim 1, characterized in that: The main control circuit also includes a low voltage protection circuit, The input end of the low voltage protection circuit is connected to the output end of the switch circuit for receiving the voltage signal. The output end of the low voltage protection circuit is connected to the voltage feedback end of the main controller.

6. The photoelectric induction LED lamp control circuit according to claim 5, characterized in that: The low voltage protection circuit comprises a tenth resistor and an eleventh resistor connected in series, One end of the tenth resistor and the eleventh resistor is connected to the voltage feedback end of the main controller, The other end of the tenth resistor is connected to the output end of the switch circuit. The other end of the eleventh resistor is connected to the common end.

7. The photoelectric sensing LED lamp control circuit according to any one of claims 1 to 5, characterized in that: It also includes a timing circuit, The input end of the timing circuit is connected to the output end of the switch circuit for receiving the voltage signal. The output end of the timing circuit is connected to the timing end of the main controller, and is used to receive the timing signal fed back by the timing circuit. The main controller outputs the PWM signal according to the feedback timing signal to adjust the lighting time of the LED module.

8. The photoelectric induction LED lamp control circuit according to claim 3, characterized in that: Also includes battery charging circuit, The input end of the battery charging circuit is connected to the external power supply end. The output end of the battery charging circuit is connected to the positive electrode of the battery module.

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