Lithium battery charging protection circuit with automatic switching function

Abstract

A lithium battery charging protection circuit with an automatic switching function comprises a charging chip U1, a diode D1, a diode D2 and an MOS transistor Q1, an external power supply + 5V supplies power to the charging chip U1 and is connected with the anode of the diode D1, the cathode of the diode D1 is connected with an output end + VOUT, the cathode of the diode D2 is connected with the output end + VOUT, the source electrode of the MOS transistor Q1 is connected with the output end + VOUT, and the source electrode of the MOS transistor Q1 is connected with the output end + VOUT. The drain electrode of the MOS tube Q1 is connected with the anode of the diode D2. The diode D1, the diode D2 and the MOS tube Q1 form a switching circuit, and the automatic switching circuit is used, so that the problem of'blockage 'occurring when the small Bluetooth sound equipment plays sound while being charged can be solved.

Description

Technical Field

[0001] The utility model relates to a protection circuit, in particular to a lithium battery charging protection circuit with automatic switching. Background Art

[0002] Many speakers experience stuttering when playing while charging. This is because the entire circuit is powered by the battery. While the battery is charging, the entire unit is actually using the battery charging current, which is insufficient for the entire speaker. This causes the speaker to appear overloaded and stutter. Without an automatic switching circuit, long-term use may damage the charging IC, especially when charging and playing at high volumes. Summary of the Invention

[0003] The technical problem to be solved by the utility model is to provide a circuit with automatic switching lithium battery charging protection to solve the "stuttering" phenomenon during audio playback.

[0004] To solve the above technical problems, the technical solution of the present invention is: a circuit with automatic switching lithium battery charging protection, including a charging chip U1, a diode D1, a diode D2 and a MOS transistor Q1. The charging chip model is TP4056. An external power supply +5V supplies power to the charging chip U1 and is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the output terminal +VOUT. The positive electrode of the battery is respectively connected to the 5th pin of the charging chip U1, the output terminal VBAT and the anode of the diode D2. The negative electrode of the battery is respectively connected to the 1st pin of the charging chip U1 and ground. A capacitor C3 is provided between the 5th pin and the 1st pin of the charging chip U1. The cathode of the diode D2 is connected to the output terminal +VOUT. The source of the MOS transistor Q1 is connected to the output terminal +VOUT. The drain of the MOS transistor Q1 is connected to the anode of the diode D2. The drain of the MOS transistor Q1 is grounded through a capacitor C49. The gate of the MOS transistor Q1 is grounded after passing through resistors R10 and R11. The external power supply +5V is connected between the resistors R10 and R11. The principle of the utility model is as follows: when the external power supply +5V appears, the current passes directly through the diode D1 to supply the whole machine with work, and at the same time the gate voltage of the MOS tube Q1 is pulled up, so that the difference between the gate voltage and the source voltage is very small, the MOS tube Q1 is cut off, and the current from the output terminal +VOUT is prevented from flowing to the output terminal +VBAT. In this way, when there is an external power supply, the external power supply is +5V and charges the battery at the same time; when the external power supply +5V is not supplied, the gate of the MOS tube Q1 is pulled down to the ground. Since the battery is connected, the voltage between the gate and the source is more than 3V, the MOS tube Q1 is turned on, and the output terminal +VABT supplies power to the whole machine.

[0005] As an improvement, pins 4 and 8 of the charging chip U1 are connected to the external power supply +5V, pin 7 of the charging chip U1 is connected to the charging LED, pin 6 of the charging chip U1 is grounded, pin 2 of the charging chip U1 is grounded through resistor R8, and pins 3 and 9 of the charging chip U1 are grounded.

[0006] As an improvement, it further includes a USB interface, and the external power supply +5V is connected to the voltage terminal of the USB interface.

[0007] Compared with the prior art, the present invention has the following beneficial effects:

[0008] The use of an automatic switching circuit can solve the "stuttering" problem that occurs when small Bluetooth speakers are charging and playing sound at the same time, avoid damage to the charging chip, and enhance the reliability of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is the circuit principle diagram of the utility model. DETAILED DESCRIPTION

[0010] The present invention will be further described below in conjunction with the accompanying drawings.

[0011] like Figure 1 As shown, a lithium battery charging protection circuit with automatic switching includes a charging chip U1, a diode D1, a diode D2 and a MOS transistor Q1; the diode D1, the diode D2 and the MOS transistor Q1 form a switching circuit, and the charging chip model is TP4056; an external power supply +5V supplies power to the charging chip U1 and is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the output terminal +VOUT, the positive electrode of the battery is respectively connected to the 5th pin of the charging chip U1, the output terminal VBAT and the anode of the diode D2, the negative electrode of the battery is respectively connected to the 1st pin of the charging chip U1 and ground, a capacitor C3 is provided between the 5th pin and the 1st pin of the charging chip U1, and the cathode of the diode D2 is connected to the output terminal +VOUT The circuit is connected by T, the source of the MOS transistor Q1 is connected to the output terminal +VOUT, the drain of the MOS transistor Q1 is connected to the anode of the diode D2, the drain of the MOS transistor Q1 is grounded through the capacitor C49, the gate of the MOS transistor Q1 is grounded after passing through the resistors R10 and R11, and the external power supply +5V is connected between the resistors R10 and R11; the 4th and 8th pins of the charging chip U1 are connected to the external power supply +5V, the 7th pin of the charging chip U1 is connected to the charging LED, the 6th pin of the charging chip U1 is grounded, the 2nd pin of the charging chip U1 is grounded through the resistor R8, and the 3rd and 9th pins of the charging chip U1 are grounded; and a USB interface is also included, and the external power supply +5V is connected to the voltage terminal of the USB interface.

[0012] The principle of the utility model is as follows: when the external power supply +5V appears, the current passes directly through the diode D1 to supply the whole machine with work, and at the same time the gate voltage of the MOS tube Q1 is pulled up, so that the difference between the gate voltage and the source voltage is very small, the MOS tube Q1 is cut off, and the current from the output terminal +VOUT is prevented from flowing to the output terminal +VBAT. In this way, when there is an external power supply, the external power supply is +5V and charges the battery at the same time; when the external power supply +5V is not supplied, the gate of the MOS tube Q1 is pulled down to the ground. Since the battery is connected, the voltage between the gate and the source is more than 3V, the MOS tube Q1 is turned on, and the output terminal +VABT supplies power to the whole machine.

Claims

1. A lithium battery charging protection circuit with automatic switching, characterized by: The present invention comprises a charging chip U1, a diode D1, a diode D2 and a MOS transistor Q1. The charging chip is TP4056. An external power supply +5V supplies power to the charging chip U1 and is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the output terminal +VOUT. The positive electrode of the battery is respectively connected to the 5th pin of the charging chip U1, the output terminal VBAT and the anode of the diode D2. The negative electrode of the battery is respectively connected to the 1st pin of the charging chip U1 and the ground. A capacitor C3 is provided between the 5th pin and the 1st pin of the charging chip U1. The cathode of the diode D2 is connected to the output terminal +VOUT. The source of the MOS transistor Q1 is connected to the output terminal +VOUT. The drain of the MOS transistor Q1 is connected to the anode of the diode D2. The drain of the MOS transistor Q1 is grounded via a capacitor C49. The gate of the MOS transistor Q1 is grounded via resistors R10 and R11. The external power supply +5V is connected between the resistors R10 and R11.

2. A lithium battery charging protection circuit with automatic switching according to claim 1, characterized in that: Pins 4 and 8 of the charging chip U1 are connected to the external power supply +5V, pin 7 of the charging chip U1 is connected to the charging LED, pin 6 of the charging chip U1 is grounded, pin 2 of the charging chip U1 is grounded through resistor R8, and pins 3 and 9 of the charging chip U1 are grounded.

3. The circuit for lithium battery charging protection with automatic switching according to claim 1, characterized in that: It also includes a USB interface, and an external power supply +5V is connected to a voltage terminal of the USB interface.

Images