Battery charging anti-reverse connection and anti-backflow circuit
By using a circuit structure composed of MOSFETs and transistors, combined with capacitors and resistors, the problems of unsatisfactory reverse connection protection and reverse current in existing technologies are solved, thereby achieving safer battery charging and extended battery life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-10
- Publication Date
- 2026-03-24
AI Technical Summary
In existing reverse connection protection circuits, the voltage drop of the rectifier diode is relatively large, resulting in an unsatisfactory reverse connection protection effect and an inability to effectively prevent reverse current flow, which can easily burn out the charger.
The circuit structure uses MOSFETs and transistors, combined with capacitors and resistors to form a loop to prevent reverse connection and backflow. The parasitic diode of the MOSFET and the conduction characteristics of the transistor ensure the correct current direction.
It effectively prevents reverse connection and backflow current during battery charging, protects the charger, extends its service life, and has a simple structure and low cost.
Smart Images
Figure CN224037113U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of charger, concretely relates to a battery charging anti-reverse connection and anti-backflow circuit. BACKGROUND
[0002] Mobile phone adapter is actually composed of a stable power supply (mainly voltage stabilizing power supply, providing stable working voltage and sufficient current) plus necessary constant current, voltage limiting, time limiting control circuit. The output parameters marked on the original charger (referring to line charging): such as output 5.0V / 1A, output 5.0V / 1500mA-11200, which refers to the relevant parameters of internal voltage stabilizing power supply. The charger of mobile phone commonly used lithium ion battery adopts constant current voltage limiting charging system, and the charging current generally adopts C2, that is, two hours charging rate, for example, 500mAh battery adopts 250mA charging about two hours to reach 4.2V and then constant voltage charging.
[0003] Some anti-reverse connection circuits adopt a rectifier diode to prevent reverse connection and backflow, but the effect is poor and not ideal due to the large voltage drop of the diode. CONTENT OF THE UTILITY MODEL
[0004] The utility model discloses a battery charging anti-reverse connection and anti-backflow circuit to solve at least one technical problem existing in the prior art.
[0005] In order to realize the above-mentioned purpose, the utility model adopts the following technical scheme:
[0006] A battery charging anti-reverse connection and anti-backflow circuit, including power input terminal Vin, MOS tube Q1, triode Q2 and triode Q3 and battery V, the output pin 2 of MOS tube Q1 is connected with power input terminal Vin, the input pin 3 of MOS tube Q1 is connected with the pin 1 of battery V, the input pin 3 of triode Q3 is connected with one end of the pin 1 of battery V, the output pin 2 of triode Q3 is connected with one end of the pin 2 of battery V, the input pin 1 of triode Q3 is connected with the input pin 1 of triode Q2;The input pin 3 of triode Q2 is connected with power input terminal Vin, and the output pin 2 of triode Q2 is connected with one end of the pin 2 of battery V.
[0007] As a preferred embodiment of the utility model, the pin 2 of triode Q2 is connected with a resistance R1 and then grounded, and the pin 2 of triode Q3 is connected with a resistance R2 and then grounded.
[0008] As a preferred embodiment of the utility model, the pin 1 and the pin 2 of battery V are connected with a capacitor C1.
[0009] As a preferred embodiment of the utility model, the capacitor C1 is a load capacitor.
[0010] As a preferred embodiment of the utility model, the pin 1 and the pin 2 of the battery V are connected in series with a resistor R3.
[0011] Compared with the prior art, the battery charging anti-reverse connection and anti-backflow circuit has the following beneficial effects:
[0012] 1. The battery charging anti-reverse connection and anti-backflow circuit can effectively prevent the burning of the charger caused by the reverse connection or backflow current during the battery charging;
[0013] 2. The circuit has simple structure, low cost and easy production.
[0014] 3. The reverse connection and backflow are prevented, and the service life is effectively prolonged. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 The circuit component diagram is described in the utility model. DETAILED DESCRIPTION
[0016] The technical solutions in the embodiments of the utility model will be clearly and completely described in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments.
[0017] In the description of the utility model, it should be understood that the terms "up", "down", "front", "back", "left", "right", "top", "bottom", "in", "out" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the utility model and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the utility model.
[0018] Please refer to the drawings Figure 1As shown in the embodiment, the battery charging reverse connection and reverse flow prevention circuit comprises a power input end Vin, a MOS tube Q1, a triode Q2, a triode Q3 and a battery V, the output pin 2 of the MOS tube Q1 is connected with the power input end Vin, the input pin 3 of the MOS tube Q1 is connected with the pin 1 of the battery V, the input pin 3 of the triode Q3 is connected with one end of the pin 1 of the battery V, the output pin 2 of the triode Q3 is connected with one end of the pin 2 of the battery V, and the input pin 1 of the triode Q3 is connected with the input pin 1 of the triode Q2; the input pin 3 of the triode Q2 is connected with the power input end Vin, and the output pin 2 of the triode Q2 is connected with one end of the pin 2 of the battery V, wherein the pin 2 of the triode Q2 is connected with a resistor R1 in series and then grounded, the pin 2 of the triode Q3 is connected with a resistor R2 in series and then grounded, the pin 1 and the pin 2 of the battery V are connected with a capacitor C1 in series, and the capacitor C1 is a load capacitor.
[0019] The utility model working principle:
[0020] The above embodiment realizes the effect of preventing reverse connection: when the charger is powered on at the moment, Figure 1 The internal parasitic diode of the MOS tube Q1 is turned on to form a loop, the potential of the source S is about Vbat-0.7V, the potential of the gate G is 0, the opening voltage of the MOS tube is: 4Ugs-0=(Vbat-0.7), the gate is low, the PMOS DS is turned on, the parasitic diode is short-circuited, and the system is connected to form a loop through the PMOS DS, and the normal charging is realized.
[0021] If the positive and negative of the power supply are connected reversely, the conduction voltage of the PMOS is greater than 0, the PMOS J is cut off, the parasitic diode is reversely connected, and the circuit is disconnected, thereby protection is formed.
[0022] The above embodiment realizes the effect of preventing reverse flow: when the input voltage normally charges the battery, since the MOS tube Q1 has a certain internal resistance when it is turned on, a certain pressure difference is formed on the input voltage and the battery voltage, so that Vin>Vout, the triode Q3 is turned on, and the triode Q2 is cut off. The gate of the MOS tube Q1 is turned on, and the charging can be normally performed.
[0023] When the input voltage is disconnected to supply power to the battery, since the load capacitor C1 exists, VinVout, the triode Q2 is turned on, and the triode Q3 is cut off. The MOS tube is closed, so that when the input voltage is suddenly disconnected, the MOS tube Q1 is immediately turned off to block the path of the battery current flowing to the power supply, and protection is realized. In addition, the service life can be prolonged.
[0024] The above merely describes a preferred embodiment of the present application, and the protection scope of the present application is not limited thereto, and any skilled person in the art, according to the technical scheme and the inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A battery charging circuit for preventing reverse connection and backflow, characterized in that: The application relates to a power input terminal Vin, a MOS transistor Q1, a triode Q2 and a triode Q3 and a battery V, wherein the output pin 2 of the MOS transistor Q1 is connected with the power input terminal Vin, the input pin 3 of the MOS transistor Q1 is connected with the pin 1 of the battery V, the input pin 3 of the triode Q3 is connected with one end of the pin 1 of the battery V, the output pin 2 of the triode Q3 is connected with one end of the pin 2 of the battery V, and the input pin 1 of the triode Q3 is connected with the input pin 1 of the triode Q2; the input pin 3 of the triode Q2 is connected with the power input terminal Vin, and the output pin 2 of the triode Q2 is connected with one end of the pin 2 of the battery V.
2. The battery charge reverse connection and backflow prevention circuit according to claim 1, characterized in that: The pin 2 of the triode Q2 is connected with a resistor R1 in series and then grounded, and the pin 2 of the triode Q3 is connected with a resistor R2 in series and then grounded.
3. The battery charge reverse connection and backflow prevention circuit of claim 1, wherein: A capacitor C1 is connected in series between the pin 1 and the pin 2 of the battery V.
4. The battery charge reverse connection and backflow prevention circuit of claim 3, wherein: The capacitor C1 is a load capacitor.
5. The battery charge reverse connection and backflow prevention circuit of claim 1, wherein: A resistor R3 is connected in series between the pin 1 and the pin 2 of the battery V.