Improved circuit of battery low-electric-trickle charging system

Abstract

The utility model belongs to the field of portable electronic equipment, and relates to a battery low-electric-trickle charging system improvement circuit which comprises an MCU, a charging circuit, a voltage division circuit and a battery power supply circuit. The input end of the charging circuit is connected with the charger, and the output end is connected with the MCU; the input end of the battery power supply circuit is connected with a BAT + port of the battery, and the output end of the battery power supply circuit is connected with the MCU; the voltage division circuit is connected between the charger and the battery power supply circuit; the voltage division circuit can control on and off of the battery power supply circuit; the system has remarkable advantages in the aspects of independent charging and power supply, seamless power supply switching, reduction of product cost, improvement of charging flexibility, improvement of charging efficiency, simplification of structure installation and maintenance, improvement of safety and reliability and the like. The advantages ensure that trickle charging can be effectively carried out under the condition that the battery voltage is extremely low, and normal starting and working of the MCU are ensured, so that the stability of the system and the user experience are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of portable electronic devices, and particularly relates to a battery low trickle charging system improvement circuit. BACKGROUND

[0002] In portable electronic devices, the charging and management system of the battery is crucial. These devices usually rely on lithium-ion or lithium-polymer batteries as their primary power source. To prolong the battery life and ensure the device can be used normally after a long period of non-use, the charging circuit usually has constant current charging and trickle charging functions. Constant current charging is to charge quickly with a fixed current when the battery voltage is low, while trickle charging is to slowly supplement with a small current when the battery is close to full to avoid overcharging and protect the battery.

[0003] In the case of extremely low battery voltage, such as self-discharge caused by long-term non-use or improper storage of the device, the battery may need trickle charging to recover to a voltage level that can start the device. However, the startup of the system MCU (Micro Control Unit) also requires a certain current, which may cause the battery charging current to be insufficient to provide the startup current for the MCU at the same time, resulting in the device being unable to start or frequent restarts.

[0004] To solve this problem, existing implementations may include a basic charging protection circuit that can cut off the power supply to the MCU when the battery voltage is below a certain threshold to prevent the MCU from attempting to start when the battery is low. Such a solution may be implemented through a simple voltage detection circuit and a switch, but they usually do not have the function of automatically switching the power source when the charger is plugged in.

[0005] Alternatively, some existing solutions may include the use of a low-dropout linear regulator to ensure that the MCU does not attempt to start when the battery voltage is low. Another solution may be to control through software, when the battery voltage is detected to be below a certain threshold, to disable the MCU from starting until the battery voltage is charged to a safe level.

[0006] However, these solutions have their limitations, such as not being able to directly provide enough current to the MCU when charging, or not being able to immediately restore the normal operation of the MCU after the battery voltage is restored. Therefore, how to optimize the startup and charging process of the device is a problem that needs to be solved. SUMMARY

[0007] The purpose of the present application is to provide a battery low trickle charging system improvement circuit to solve the problem of existing devices being unable to start or frequent restarts when they have been unused for a long time or improperly stored.

[0008] The technical scheme of the present application is: a battery low current charging system improvement circuit, comprising an MCU, a charging circuit, a voltage dividing circuit and a battery power supply circuit; the input end of the charging circuit is connected with a charger, and the output end is connected with the MCU; the input end of the battery power supply circuit is connected with the BAT+ port of a battery, and the output end is connected with the MCU; the voltage dividing circuit is connected between the charger and the battery power supply circuit; the voltage dividing circuit can input the power of the charger into the battery power supply circuit for level conversion, and control the opening and closing of the battery power supply circuit; when the charger is connected with the charging circuit, the charging circuit is opened, the battery power supply circuit is closed, and the charger supplies power to the MCU through the charging circuit; when the charger is unplugged, the charging circuit is closed, the battery power supply circuit is opened, and the battery supplies power to the MCU through the battery power supply circuit.

[0009] Preferably, the charging circuit comprises a first resistor, a first MOS tube, a second resistor, a second MOS tube, a third resistor and a third MOS tube; one end of the first resistor is connected with the gate of the first MOS tube, and the other end is connected with the gate of the third MOS tube; the drain of the first MOS tube is connected with the drain of the second MOS tube, and the source is connected with the drain of the third MOS tube; one end of the second resistor is connected with the drain of the second MOS tube, and the other end is connected with the source of the second MOS tube; the drain of the second MOS tube is connected with the VDD port of the MCU, and the source is connected with the drain of the third MOS tube; one end of the third resistor is connected with the gate of the third MOS tube, and the other end is grounded, and the source of the third MOS tube is grounded; the first MOS tube and the second MOS tube are P-type MOS tubes, and the third MOS tube is an N-type MOS tube.

[0010] Preferably, the battery power supply circuit comprises a fifth resistor, a first capacitor and a fourth MOS tube; one end of the fifth resistor is connected with the BAT+ port of the battery, and the other end is connected with the drain of the fourth MOS tube; the gate of the fourth MOS tube is connected with the voltage dividing circuit, and the source is connected with the BAT+ port of the battery; one end of the first capacitor is connected with the source of the fourth MOS tube, and the other end is grounded; the fourth MOS tube is a P-type MOS tube.

[0011] Preferably, the voltage dividing circuit comprises a fourth resistor and a seventh resistor, and the fourth resistor and the seventh resistor are connected in series; the other end of the seventh resistor is connected with the charger, and the other end of the fourth resistor is grounded; the gate of the fourth MOS tube is connected between the fourth resistor and the seventh resistor.

[0012] Preferably, the battery power supply circuit further comprises a Schottky diode, which is connected in parallel with the fourth MOS tube.

[0013] Preferably, a voltage regulator circuit is provided between the charging circuit and the battery power supply circuit. The voltage regulator circuit includes a voltage regulator and a sixth resistor. The power supply terminal of the voltage regulator is connected to the charger, and the output terminal is connected to the BAT+ port of the battery. One end of the sixth resistor is connected to pin 5 of the voltage regulator, and the other end is grounded.

[0014] The improved circuitry for the low-voltage trickle charging system in this application offers significant advantages in terms of independent charging power supply, seamless power supply switching, reduced product costs, increased charging flexibility, improved charging efficiency, simplified structural installation and maintenance, and enhanced safety and reliability. These advantages ensure effective trickle charging even when the battery voltage is extremely low, and guarantee the normal startup and operation of the MCU, thereby significantly improving system stability and user experience. Attached Figure Description

[0015] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0016] Figure 1 This is the overall circuit structure diagram of this application;

[0017] Figure 2 This is a schematic diagram of the MCU structure in this application;

[0018] Figure 3 This is a schematic diagram of the voltage regulator circuit structure of this application.

[0019] 1. MCU; 2. Battery; 3. First resistor; 4. First MOSFET; 5. Second resistor; 6. Second MOSFET; 7. Third resistor; 8. Third MOSFET; 9. Fifth resistor; 10. First capacitor; 11. Fourth MOSFET; 12. Fourth resistor; 13. Seventh resistor; 14. Schottky diode; 15. Voltage regulator; 16. Sixth resistor. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] A circuit for improving low-power trickle charging systems, such as Figures 1-2The system includes MCU1, a charging circuit, a voltage divider circuit, and a battery power supply circuit. The input of the charging circuit is connected to the charger, and the output is connected to MCU1. The input of the battery power supply circuit is connected to the BAT+ port of battery 2, and the output is connected to MCU1. The voltage divider circuit is connected between the charger and the battery power supply circuit. The voltage divider circuit can convert the electrical energy input from the charger to the battery power supply circuit for level conversion and control the battery power supply circuit to turn on and off. When the charger is connected to the charging circuit, the charging circuit is on, the battery power supply circuit is off, and the charger supplies power to MCU1 through the charging circuit. When the charger is unplugged, the charging circuit is off, the battery power supply circuit is on, and battery 2 supplies power to MCU1 through the battery power supply circuit, enabling effective trickle charging of battery 2 even when its voltage is extremely low.

[0022] Preferably, the charging circuit includes a first resistor 3, a first MOSFET 4, a second resistor 5, a second MOSFET 6, a third resistor 7, and a third MOSFET 8. One end of the first resistor 3 is connected to the gate of the first MOSFET 4, and the other end is connected to the gate of the third MOSFET 8. The drain of the first MOSFET 4 is connected to the drain of the second MOSFET 6, and the source is connected to the drain of the third MOSFET 8. One end of the second resistor 5 is connected to the drain of the second MOSFET 6, and the other end is connected to the source of the second MOSFET 6. The drain of the second MOSFET 6 is connected to the VDD port of MCU1, and the source is connected to the drain of the third MOSFET 8. One end of the third resistor 7 is connected to the gate of the third MOSFET 8, and the other end is grounded. The source of the third MOSFET 8 is grounded. The first MOSFET 4 and the second MOSFET 6 are P-type MOSFETs, and the third MOSFET 8 is an N-type MOSFET.

[0023] When the gate of the third MOSFET 8 is connected to a high level, it conducts and is grounded, causing the sources of the first MOSFET 4 and the second MOSFET 6 to form a low level. This turns on the first MOSFET 4 and the second MOSFET 6, and the charging circuit is activated. Conversely, when the gate of the third MOSFET 8 is connected to a low level, the charging circuit is deactivated.

[0024] Preferably, the battery power supply circuit includes a fifth resistor 9, a first capacitor 10, and a fourth MOSFET 11. One end of the fifth resistor 9 is connected to the BAT+ port of the battery 2, and the other end is connected to the drain of the fourth MOSFET 11. The gate of the fourth MOSFET 11 is connected to a voltage divider circuit, and its source is connected to the BAT+ port of the battery 2. One end of the first capacitor 10 is connected to the source of the fourth MOSFET 11, and the other end is grounded for filtering. The fourth MOSFET 11 is a P-type MOSFET. When the fourth MOSFET 11 receives a high-level signal, the fourth MOSFET 11 is turned off, the battery power supply circuit is shut down, and the battery 2 cannot supply power to the MCU1. Conversely, when the fourth MOSFET 11 receives a low-level signal, the battery power supply circuit is turned on, and the battery 2 can supply power to the MCU1.

[0025] Preferably, the voltage divider circuit includes a fourth resistor 12 and a seventh resistor 13, which are connected in series. The other end of the seventh resistor 13 is connected to the charger, and the other end of the fourth resistor 12 is grounded. The gate of the fourth MOSFET 11 is connected between the fourth resistor 12 and the seventh resistor 13. When the charger is connected, electrical energy is transferred to the gate of the fourth MOSFET 11 through the voltage divider circuit, forming a high level. The fourth MOSFET 11 is not conducting, and the battery power supply circuit is turned off. When the charger is unplugged, the gate of the fourth MOSFET 11 forms a low level, the battery power supply circuit is turned on, and MCU1 can be charged by battery 2.

[0026] Preferably, the battery power supply circuit also includes a Schottky diode 14, which is connected in parallel with the fourth MOSFET 11. Before the fourth MOSFET 11 is fully turned on, the BAT+ port of battery 2 supplies power to the VDD port through the Schottky diode 14. Since the forward voltage drop of the Schottky diode 14 is approximately 0.3V, which is lower than the voltage drop of the parasitic diode inside the fourth MOSFET 11, this helps to reduce the drop in VDD voltage during switching and protects MCU1 from the effects of low voltage.

[0027] Combination Figure 3 Preferably, to further improve charging performance, a voltage regulator circuit is provided between the charging circuit and the battery power supply circuit. The voltage regulator circuit includes a voltage regulator 15 and a sixth resistor 16. The power supply terminal of the voltage regulator 15 is connected to the charger, and the output terminal is connected to the BAT+ port of the battery 2. One end of the sixth resistor 16 is connected to pin 5 of the voltage regulator 15, and the other end is grounded. The voltage regulator 15 is capable of providing a stable DC voltage power supply and stabilizing the output voltage when the AC power supply voltage or load changes, suppressing ripple voltage, and eliminating AC noise generated by the power supply.

[0028] The overall work process is as follows:

[0029] When the charger is plugged in, it outputs a 5V voltage to the charging circuit. This 5V voltage is divided by the fourth resistor 12 and the seventh resistor 13, giving a high-level signal to the gate of the fourth MOSFET 11, causing the fourth MOSFET 11 to turn off. This cuts off the power supply path from the BAT+ port of battery 2 to MCU1. In this way, battery 2 will not be affected by the startup current of MCU1.

[0030] Furthermore, since trickle charging is only applied to battery 2, the trickle charging current output from pin 3 of the charging chip U2 flows only to battery 2 and is not diverted to MCU1.

[0031] Simultaneously, the 5V charging voltage, after being divided by the first resistor 3 and the third resistor 7, provides a high-level signal to the gate of the third MOSFET 8, turning it on. This allows the first MOSFET 4 and the second MOSFET 6 to directly supply the charger's voltage to the VDD port of MCU1, bypassing the battery 2.

[0032] When the charger is unplugged: the voltage output from the charger port becomes 0V, and the gate of the third MOSFET 8 receives a low-level signal, causing the third MOSFET 8 to de-conduct. At this time, the VDD port, through the parasitic diode inside the second MOSFET 6 and the second resistor 5, pulls the gates of the first MOSFET 4 and the second MOSFET 6 high, thus preventing the first MOSFET 4 and the second MOSFET 6 from conducting and stopping the charger from supplying power to the MCU1.

[0033] Simultaneously, as the voltage output from the charger port becomes 0V, the voltage division between the fourth resistor 12 and the seventh resistor 13 provides a low-level signal to the gate of the fourth MOSFET 11, causing the fourth MOSFET 11 to conduct. Thus, battery 2BAT+ is directly connected to the VDD port of MCU1 via the fourth MOSFET 11, achieving a seamless switch from charging to battery 2 power supply.

[0034] In summary, this application has the following advantages:

[0035] 1. Independent charging power supply

[0036] 1.1 Improve charging efficiency: When the charger is plugged in, the power supply from the battery to the MCU is automatically cut off, and the charger directly supplies power to the MCU. This ensures that the charging chip focuses on trickle charging of the battery and avoids current diversion.

[0037] 1-2. Reduced interference: This design avoids the influence of the MCU startup current on the battery charging current, improving the efficiency and stability of trickle charging.

[0038] 2. Seamless power supply switching

[0039] 2-1. Maintain system operation: When the charger is unplugged, the circuit will automatically restore the battery power supply to the MCU, achieving seamless switching and ensuring continuous system operation.

[0040] 2-2. Preventing frequent restarts: This seamless switching mechanism avoids the problem of frequent MCU restarts due to insufficient power, thus improving the stability and reliability of the system.

[0041] 3. Reduce product costs

[0042] 3-1. Optimize circuit design: By optimizing the circuit design, the use of expensive dedicated power management ICs is avoided, thereby reducing the cost of the product.

[0043] 3-2. Enhance competitiveness: Reducing the use of components simplifies the circuit structure, further reduces production costs, and enhances the product's market competitiveness.

[0044] 4. Improve charging flexibility

[0045] 4-1. Adaptable to different battery types: The charging management scheme designed in this invention is more intelligent and flexible, applicable to different types of batteries and different voltage levels, thus expanding the product's applicability.

[0046] 4-2. Improved user experience: Users no longer need to worry about matching battery type and voltage level, which improves the convenience of the product and the user experience.

[0047] 5. Simplify structural installation and maintenance

[0048] 5-1 Modular Design: The circuit design of this invention is simple, easy to assemble and maintain, and realizes modular and standardized production.

[0049] 5-2. Reduced maintenance costs: The modular replacement design reduces maintenance costs and facilitates later repairs and replacements.

[0050] Finally, it should be noted that the accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0051] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A circuit for improving a low-charge trickle charging system for batteries, characterized in that: It includes an MCU (1), a charging circuit, a voltage divider circuit, and a battery power supply circuit; the input terminal of the charging circuit is connected to the charger, and the output terminal is connected to the MCU (1); the input terminal of the battery power supply circuit is connected to the BAT+ port of the battery (2), and the output terminal is connected to the MCU (1); the voltage divider circuit is connected between the charger and the battery power supply circuit; the voltage divider circuit can input the electrical energy of the charger into the battery power supply circuit for level conversion, and control the opening and closing of the battery power supply circuit; when the charger is connected to the charging circuit, the charging circuit is on, the battery power supply circuit is off, and the charger supplies power to the MCU (1) through the charging circuit; when the charger is unplugged, the charging circuit is off, the battery power supply circuit is on, and the battery (2) supplies power to the MCU (1) through the battery power supply circuit. The charging circuit includes a first resistor (3), a first MOSFET (4), a second resistor (5), a second MOSFET (6), a third resistor (7), and a third MOSFET (8); one end of the first resistor (3) is connected to the gate of the first MOSFET (4), and the other end is connected to the gate of the third MOSFET (8); the drain of the first MOSFET (4) is connected to the drain of the second MOSFET (6), and the source is connected to the drain of the third MOSFET (8); one end of the second resistor (5) is connected to the gate of the third MOSFET (8). The drain of transistor (6) is connected to the other end, and the source of the second MOSFET (6) is connected to the source of the second MOSFET (6); the drain of the second MOSFET (6) is connected to the VDD port of the MCU (1), and the source is connected to the drain of the third MOSFET (8); one end of the third resistor (7) is connected to the gate of the third MOSFET (8), and the other end is grounded; the source of the third MOSFET (8) is grounded; the first MOSFET (4) and the second MOSFET (6) are P-type MOSFETs, and the third MOSFET (8) is an N-type MOSFET; The battery power supply circuit includes a fifth resistor (9), a first capacitor (10), and a fourth MOSFET (11); one end of the fifth resistor (9) is connected to the BAT+ port of the battery (2), and the other end is connected to the drain of the fourth MOSFET (11); the gate of the fourth MOSFET (11) is connected to the voltage divider circuit, and the source is connected to the BAT+ port of the battery (2); one end of the first capacitor (10) is connected to the source of the fourth MOSFET (11), and the other end is grounded; the fourth MOSFET (11) is a P-type MOSFET.

2. The battery low-charge trickle charging system improvement circuit as described in claim 1, characterized in that: The voltage divider circuit includes a fourth resistor (12) and a seventh resistor (13), which are connected in series. The other end of the seventh resistor (13) is connected to the charger, and the other end of the fourth resistor (12) is grounded. The gate of the fourth MOSFET (11) is connected between the fourth resistor (12) and the seventh resistor (13).

3. The battery low-charge trickle charging system improvement circuit as described in claim 1, characterized in that: The battery power supply circuit also includes a Schottky diode (14), which is connected in parallel with a fourth MOSFET (11).

4. The battery low-charge trickle charging system improvement circuit as described in claim 1, characterized in that: A voltage regulator circuit is provided between the charging circuit and the battery power supply circuit. The voltage regulator circuit includes a voltage regulator (15) and a sixth resistor (16). The power supply terminal of the voltage regulator (15) is connected to the charger, and the output terminal is connected to the BAT+ port of the battery (2). One end of the sixth resistor (16) is connected to pin 5 of the voltage regulator (15), and the other end is grounded.

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