CN209767208U

CN209767208U - Self-switching circuit of polymer lithium battery based on USB charging

Info

Publication number: CN209767208U
Application number: CN201921011461.3U
Authority: CN
Inventors: 于海军; 江刚
Original assignee: Zhongshan Good Sense Technology Co Ltd
Current assignee: Zhongshan Good Sense Technology Co Ltd
Priority date: 2019-07-02
Filing date: 2019-07-02
Publication date: 2019-12-10
Anticipated expiration: 2029-07-02

Abstract

The utility model discloses a polymer lithium battery self-switching circuit based on USB charging, which comprises a USB interface, a charging management module, a lithium battery, a switch tube and an output end; the USB interface, the charging management module and the lithium battery are sequentially connected, the anode of the lithium battery is connected with the drain electrode of the switch tube, the grid electrode of the switch tube is connected with the USB interface, and the source electrode of the switch tube is connected with the output end; the USB interface is connected with the grid electrode of the switching tube, and the grid electrode of the switching tube, the pull-down resistor and the grounding end are sequentially connected; and a reverse-filling prevention diode is connected between the source electrode and the grid electrode of the switch tube, the anode of the reverse-filling prevention diode is connected with the grid electrode of the switch tube, and the cathode of the reverse-filling prevention diode is connected with the source electrode of the switch tube. The utility model discloses make the lithium cell only accomplish trickle charge process under the mode of charging, then get into normal charge mode after being "activated", effectively solved the problem that can't charge.

Description

self-switching circuit of polymer lithium battery based on USB charging

Technical Field

The utility model belongs to the technical field of the lithium cell technique and specifically relates to a polymer lithium cell is from switching circuit based on USB charges.

Background

Along with the popularization of wearable electronic products, more and more electronic products adopt a rechargeable small-capacity polymer lithium battery as a power supply. The normal charging process of the polymer lithium battery must go through three stages: a trickle mode, a constant current mode, and a constant voltage mode. After entering the trickle mode, charging is carried out by one tenth of the normal charging current, the constant current charging mode enters the normal constant current charging mode after the threshold voltage is reached, and after the constant current is charged to 4.2V, the constant voltage mode is entered and the charging is finished after the current is cut off.

In order to reduce the loss of the polymer lithium battery, the whole charging process generally adopts a constant current which is 0.5 times of the self capacity of the polymer lithium battery to charge. If the self voltage of the lithium battery is lower than the threshold voltage, the trickle charge mode is firstly started, and at the moment, the trickle charge current is one tenth of 0.5 time of the self capacity of the polymer lithium battery. The long-time placed polymer lithium battery firstly enters into the trickle charge mode after the charging cycle is started, and at the moment, if the current consumed by the battery power supply is larger than the trickle charge current, the battery can not finish the trickle charge process, so that the battery can not be activated.

SUMMERY OF THE UTILITY MODEL

the utility model provides a polymer lithium cell is from switching circuit based on USB charges solves the unable problem of normally charging of current lithium cell because of power supply consumption current is greater than trickle charging current.

The embodiment of the utility model provides a polymer lithium battery is from switching circuit based on USB charges, including USB interface, charge management module, lithium cell, switch tube and output; the USB interface, the charging management module and the lithium battery are sequentially connected, the anode of the lithium battery is connected with the drain electrode of the switch tube, the grid electrode of the switch tube is connected with the USB interface, and the source electrode of the switch tube is connected with the output end; the USB interface is connected with the grid electrode of the switching tube, and the grid electrode of the switching tube, the pull-down resistor and the grounding end are sequentially connected; and a reverse-filling prevention diode is connected between the source electrode and the grid electrode of the switch tube, the anode of the reverse-filling prevention diode is connected with the grid electrode of the switch tube, and the cathode of the reverse-filling prevention diode is connected with the source electrode of the switch tube.

Preferably, the charging management module includes a chip TP4056, pin 3 of the chip TP4056 is connected to the positive electrode of the lithium battery, and pin 1, pin 4, and pin 5 of the chip TP4056 are connected to the USB interface.

Preferably, the charging management module further comprises a current limiting resistor, a first indicator light and a second indicator light; USB interface, current-limiting resistor, first pilot lamp and chip TP 4056's 5 feet link to each other in order, USB interface, current-limiting resistor, second pilot lamp and chip TP 4056's 1 foot link to each other in order.

Preferably, a voltage stabilizing module and a filtering module are further connected between the source electrode and the output end of the switching tube.

Preferably, the voltage stabilizing module comprises a chip XC6221, wherein pins 1 and 3 of the chip XC6221 are both connected with the source of the switching tube, pin 2 of the chip XC6221 is grounded, and pin 5 of the chip XC6221 is connected with the output end.

Preferably, the filter module includes a filter capacitor, one end of the filter capacitor is connected to pin 1 of the chip XC6221, and the other end of the filter capacitor is grounded.

Preferably, a VBUS pin of the USB interface is connected to the charging management module, and the VBUS pin of the USB interface is connected to a gate of the switching tube.

the technical effects of the utility model are that:

When the USB interface is not connected with a power supply, the grid electrode of the MOS tube is pulled down to the ground through the pull-down resistor, so that the MOS tube is conducted, and the lithium battery normally supplies power to the output end. When the USB interface is connected with a power supply, the USB port provides an input source for the charging management module and the MOS tube grid, at the moment, the MOS tube is cut, the lithium battery does not supply power, the charging management module charges the lithium battery, and the USB interface supplies power to the output end through the diode. This application can directly cut off the lithium cell power supply after inserting USB, makes the lithium cell only charge after inserting USB, and does not produce the consumption. Therefore, the consumption of the lithium battery during charging is completely cut off, the lithium battery is only charged but not discharged, the lithium battery only completes the trickle charging process in the charging mode, and then enters the normal charging mode after being activated, and the problem that the lithium battery cannot be charged is effectively solved.

drawings

Fig. 1 is a schematic circuit diagram of a self-switching circuit of a USB charging-based polymer lithium battery according to an embodiment of the present invention;

Fig. 2 is a schematic circuit diagram of the voltage stabilizing module and the filtering module according to an embodiment of the present invention.

Detailed Description

The term "connected" or "connected" in the present invention means that two members are directly connected or indirectly connected through appropriate intermediate elements such as resistors, inductors, and capacitors.

The embodiment of the utility model provides a polymer lithium cell is from switching circuit based on USB charges, as shown in FIG. 1, it includes USB interface, charge management module, lithium cell J1, switch tube and output. The USB interface may be a standard interface of USB, and the VBUS pin in the USB interface is a power pin for supplying power to the USB device. The charging management module is used for managing charging of the lithium battery. The lithium Battery can be a small-capacity polymer lithium Battery, which comprises a positive Battery + and a negative Battery-. The switching tube can be an MOS tube, as shown in the figure, a P-type MOS tube can be selected, and the conduction or the closing between the source electrode and the drain electrode is controlled by the change of the voltage value input by the gate electrode. The output end is used as a power supply output end, and the corresponding power utilization device is used for being connected with the output end.

The USB interface, the charging management module and the lithium battery are sequentially connected, and specifically, the USB interface, the charging management module and the lithium battery can be sequentially connected. The VBUS pin, the charging management module and the positive electrode of the lithium battery form a charging circuit, and the USB interface charges the lithium battery through the charging management module after being connected with a power supply. The positive pole of lithium cell links to each other with the drain electrode of switch tube Q1, and the source electrode of switch tube connects the output, therefore, the supply circuit of lithium cell is switched on or is closed by the control of switch tube, and the grid of switch tube links to each other with the USB interface, and the break-make of switch tube will be supplied power by USB and determine. The grid of the switching tube, the pull-down resistor R3 and the ground terminal are connected in sequence, and when no other power supply is input to the grid of the switching tube, the grid of the switching tube is pulled down and grounded, so that the state is a low level. Meanwhile, the source electrode of the switching tube is connected with the grid electrode, and the power supply of the USB interface is output to the output end connected with the source electrode of the switching tube.

When the USB interface is not plugged into the USB power supply, the lithium battery supplies power normally. At this time, the gate G of the MOS transistor Q1 is pulled down to the ground through R3, that is, VG is equal to 0, the drain D of Q1 is connected to the anode of the lithium battery, the source S of the MOS transistor generates the voltage VS based on the unidirectional conductivity of the parasitic diode inside the MOS transistor, and at this time VGs <0, the turn-on condition of the threshold voltage of the MOS transistor is met, the MOS transistor is turned on, and the source S of the MOS transistor provides the power supply for the output terminal. The diode has a one-way conduction characteristic, and the source S of the MOS transistor does not flow into the drain D and the grid G of the MOS transistor due to the internal parasitic diode and the diode D4, so that the diode has a backflow prevention function, wherein the diode can be a Schottky diode.

When the USB interface is plugged into a USB power supply, the USB port provides an input source for the charging management module and the MOS tube grid G, and the charging management module charges the lithium battery. At this point VG is 5V and 0V < VS < 4.2V. VGS is greater than 0, the threshold voltage Vth starting condition of the MOS transistor is not met, and the MOS transistor is cut off. And the USB interface provides power to the output. At the moment, the MOS tube is cut off, the lithium battery is not consumed, and only charging is carried out, so that current cannot flow back to the drain electrode D of the MOS tube, and the effect of blocking the power supply of the battery is well played.

The charging management module may include a charging chip, for example, a chip TP4056 may be selected, where TP4056 is a complete single-cell lithium ion battery linear charger using constant current/constant voltage. The SOP8/MSOP8 package with heat sink at the bottom and the small number of external components make TP4056 very heat dissipating and portable.

Because an internal PMOSFET architecture is adopted and a reverse charging prevention circuit is added, an external isolation diode is not needed. The thermal feedback allows for automatic adjustment of the charging current to limit the chip temperature under high power operation or high ambient temperature conditions. The charging voltage is fixed at 4.2V and the charging current can be set externally by a resistor. TP4056 will automatically terminate the charging cycle when the charging current drops to set point 1/10 after the final float voltage is reached.

As shown in the figure, pin 3 of the chip TP4056 is connected to the positive electrode of the lithium battery, and the battery is charged by the output voltage of pin 3. Pin 1, 4 and 5 of chip TP4056 all link to each other with the USB interface, and 4 feet are chip TP 4056's working power supply input, and 4 feet input operating voltage after, whole chips begin work. Pins 1 and 5 serve as power inputs.

Furthermore, the USB interface, the current limiting resistor R1, the first indicator light D1 and the 5 feet of the chip TP4056 are sequentially connected, and the USB interface, the current limiting resistor R1, the second indicator light D2 and the 1 foot of the chip TP4056 are sequentially connected. The first and second indicator lamps D1 and D2 have different colors to indicate whether the charge is full.

On the basis of the above embodiment, a voltage stabilizing module and a filtering module are further connected between the source electrode and the output end of the switching tube. The voltage stabilizing module is used for stabilizing voltage and keeping the voltage output by the output end stable. The filtering module is used for filtering the impurity waves in the circuit.

In a specific embodiment, as shown in fig. 2, the voltage stabilizing module includes a chip XC6221, pins 1 and 3 of the chip XC6221 are both connected to the source of the switching tube, pin 1 is an input terminal, pin 5 is an output terminal, pin 2 of the chip XC6221 is grounded, and pin 5 of the chip XC6221 is connected to the output terminal. After the voltage is stabilized by the voltage stabilizing module, a stable power supply signal is output from the output end.

Furthermore, the filtering module includes filter capacitor, and filter capacitor can set up a plurality ofly, as shown in the figure, electric capacity C7, C8, C9 and C10 are filter capacitor, and one end of filter capacitor connects 1 foot of chip XC6221, and filter capacitor's the other end ground connection, filters the impurity wave.

The foregoing is a more detailed description of the present invention that is presented in conjunction with specific embodiments, and it is not to be understood that the specific embodiments of the present invention are limited to these descriptions. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement.

Claims

1. A polymer lithium battery self-switching circuit based on USB charges which characterized in that:

The charging management system comprises a USB interface, a charging management module, a lithium battery, a switching tube and an output end; the USB interface, the charging management module and the lithium battery are sequentially connected, the anode of the lithium battery is connected with the drain electrode of the switch tube, the grid electrode of the switch tube is connected with the USB interface, and the source electrode of the switch tube is connected with the output end; the USB interface is connected with the grid electrode of the switching tube, and the grid electrode of the switching tube, the pull-down resistor and the grounding end are sequentially connected; and a reverse-filling prevention diode is connected between the source electrode and the grid electrode of the switch tube, the anode of the reverse-filling prevention diode is connected with the grid electrode of the switch tube, and the cathode of the reverse-filling prevention diode is connected with the source electrode of the switch tube.

2. the self-switching circuit of a polymer lithium battery based on USB charging as claimed in claim 1, wherein:

The charging management module comprises a chip TP4056, wherein 3 pins of the chip TP4056 are connected with the anode of the lithium battery, and 1 pin, 4 pins and 5 pins of the chip TP4056 are connected with the USB interface.

3. The self-switching circuit of the USB charging-based polymer lithium battery as claimed in claim 2, wherein:

The charging management module further comprises a current-limiting resistor, a first indicator light and a second indicator light; USB interface, current-limiting resistor, first pilot lamp and chip TP 4056's 5 feet link to each other in order, USB interface, current-limiting resistor, second pilot lamp and chip TP 4056's 1 foot link to each other in order.

4. The self-switching circuit of a polymer lithium battery based on USB charging according to any one of claims 1-3, wherein:

And a voltage stabilizing module and a filtering module are also connected between the source electrode and the output end of the switching tube.

5. The USB charging based polymer lithium battery self-switching circuit of claim 4, wherein:

the voltage stabilizing module comprises a chip XC6221, wherein a pin 1 and a pin 3 of the chip XC6221 are both connected with a source electrode of the switch tube, a pin 2 of the chip XC6221 is grounded, and a pin 5 of the chip XC6221 is connected with the output end.

6. The USB charging based polymer lithium battery self-switching circuit of claim 5, wherein:

The filter module comprises a filter capacitor, one end of the filter capacitor is connected with pin 1 of the chip XC6221, and the other end of the filter capacitor is grounded.

7. the self-switching circuit of a polymer lithium battery based on USB charging according to any one of claims 1-3, wherein:

And a VBUS pin of the USB interface is connected with the charging management module, and is connected with a grid electrode of the switching tube.