Charging and discharging protection circuit for preventing reverse connection of POS machine power supply
By introducing a reverse connection protection circuit and a current direction detection circuit into the POS machine power supply, and using NMOS transistors and triodes to achieve reverse connection protection for the POS machine power supply, the problems of high loss and insufficient protection in the existing technology are solved, and low loss and safe power management are achieved.
Patent Information
- Application Number
- CN202422552660.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2034-10-22
AI Technical Summary
Existing POS machine power supply reverse connection protection circuits suffer from high losses and ineffective protection during charging, especially those using diodes and PMOS transistors, which have voltage drops and insufficient protection.
The system employs a POS machine power supply, reverse connection protection circuit, and current direction detection circuit that work together. It uses NMOS transistors and triodes to control the circuit's on/off state, and combines current direction detection to prevent reverse connection of positive and negative terminals, reduce circuit losses, and provide protection during charging.
It achieves low-loss protection against reverse polarity, has a simple circuit structure, and can effectively prevent circuit damage during charging and discharging, thus improving power utilization and safety.
Smart Images
Figure CN223797921U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a circuit technical field, concretely relates to a kind of for POS machine power supply anti-reverse connection charge-discharge protection circuit. BACKGROUND
[0002] POS machine is a kind of multifunctional terminal, install POS machine in credit card special cooperative merchant and receiving network point and form network with computer, and it can realize electronic funds automatic transfer, it has support consumption, pre-authorization, balance inquiry and transfer function, use safe, fast, reliable.
[0003] POS machine is a kind of mobile device, usually uses rechargeable battery to provide power source for it.Rechargeable battery as the POS machine power that can charge and discharge, it is with positive and negative, such as in use process accidentally caused the positive and negative of POS machine power reverse connection, whether it is charging or discharging, it will cause irreversible damage to POS machine power, light causes POS machine power internal circuit to burn and damage, heavy will cause POS machine power fire and cause security hidden, so it is very necessary to design the anti-positive and negative reverse connection circuit of POS machine power.
[0004] The anti-reverse connection circuit of conventional POS machine power generally uses series diode, utilizes the characteristic of diode to realize the anti-positive and negative reverse connection protection function of POS machine power, but diode will generate great voltage drop when POS machine power works, reduces the energy utilization rate of POS machine power.There is also PMOS pipe to realize the anti-positive and negative reverse connection protection function of POS machine power, but PMOS pipe can only protect the reverse connection of POS machine power when discharging, cannot play the reverse connection protection function when charging. UTILITY MODEL CONTENTS
[0005] To solve the problems in the prior art, the utility model provides a kind of for POS machine power supply anti-reverse connection charge-discharge protection circuit, by being arranged in the charge-discharge protection circuit for POS machine power supply anti-reverse connection POS machine power, anti-reverse connection protection circuit and current direction detection circuit cooperate with each other, anti-reverse connection protection circuit can control the on-off of POS machine power output according to the positive and negative connection state of output positive pole and output negative pole, the charge-discharge state of POS machine power feedback by current direction detection circuit, that is, can realize the anti-positive and negative reverse connection protection function of POS machine power, low loss, circuit structure is simple, solve the problem that diode is used in the anti-reverse connection circuit of POS machine power in prior art, high loss, PMOS pipe cannot play the reverse connection protection function when charging.
[0006] This utility model provides a charging and discharging protection circuit for reverse connection protection of POS machine power supply, including a POS machine power supply, a reverse connection protection circuit, and a current direction detection circuit. The output terminal of the POS machine power supply is connected to the input terminal of the current direction detection circuit and the input terminal of the reverse connection protection circuit. The output terminal of the current direction detection circuit is connected to the input terminal of the reverse connection protection circuit. The output terminal of the reverse connection protection circuit is connected to an output positive terminal and an output negative terminal. The output positive terminal and the output negative terminal can be connected to a charging power supply and the main control circuit board inside the POS machine. The reverse connection protection circuit is equipped with a field-effect transistor Q2, which is an NMOS transistor. The current direction detection circuit is equipped with a transistor Q1. The reverse connection protection circuit can control the on / off state of the POS machine power supply output according to the positive and negative connection states of the output positive and negative terminals and the charging and discharging state of the POS machine power supply fed back by the current direction detection circuit.
[0007] In a further improvement to this invention, the reverse connection protection circuit is further provided with resistors R1 and R2. The gate of the field-effect transistor Q2 is connected to one end of the resistor R1 and the output terminal of the current direction detection circuit. The other end of the resistor R1 is connected to the positive terminal of the POS machine power supply, one end of the resistor R2 and the output positive terminal. The source of the field-effect transistor Q2, the other end of the resistor R2 and the output negative terminal are grounded to GND_2. The drain of the field-effect transistor Q2, the negative terminal of the POS machine power supply and the input terminal of the current direction detection circuit are grounded to GND_1.
[0008] In a further improvement to this invention, the current direction detection circuit is further provided with resistors R3 and R4. The base of transistor Q1 is connected to one end of resistor R3 and one end of resistor R4. The other end of resistor R3 is grounded to GND_1. The other end of resistor R4 and the emitter of transistor Q1 are grounded to GND_2. The collector of transistor Q1 is connected to the gate of field-effect transistor Q2 and one end of resistor R1.
[0009] In a further improvement to this invention, the resistance of resistor R1 is 10KΩ.
[0010] The present invention is further improved in that the resistance of resistor R3 is 10KΩ and the resistance of resistor R4 is 10KΩ.
[0011] This utility model is further improved, and the field-effect transistor Q2 is model AO3400A.
[0012] In a further improvement to this invention, the power supply for the POS machine is a rechargeable lead-acid battery or a rechargeable lithium-ion battery.
[0013] Compared with the prior art, the beneficial effects of this utility model are as follows: It provides a charging and discharging protection circuit for reverse connection protection of POS machine power supply. By setting up a POS machine power supply, a reverse connection protection circuit and a current direction detection circuit that cooperate with each other in the charging and discharging protection circuit for reverse connection protection of POS machine power supply, the reverse connection protection circuit can control the on and off of the output of POS machine power supply according to the positive and negative connection status of the output positive and negative terminals and the charging and discharging status of POS machine power supply fed back by the current direction detection circuit. That is, it can realize the reverse connection protection function of POS machine power supply. The use of NMOS transistor with extremely low on-resistance as the protection element for reverse connection protection of POS machine power supply greatly reduces the circuit loss when POS machine power supply is working. At the same time, a transistor amplifier circuit is used to detect the current direction during charging, thereby providing the reverse connection protection function during charging. The circuit structure is simple and solves the problems of high loss of diodes and inability of PMOS transistors to play a reverse connection protection role during charging in the prior art POS machine power supply reverse connection protection circuit. Attached Figure Description
[0014] To more clearly illustrate the solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0015] Figure 1 This is a circuit diagram of a charging and discharging protection circuit for reverse connection prevention of POS machine power supply according to the present invention. Detailed Implementation
[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this invention are used to distinguish different objects, not to describe a particular order.
[0017] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0018] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.
[0019] like Figure 1 As shown, this utility model provides a charging and discharging protection circuit for reverse connection protection of a POS machine power supply, including a POS machine power supply, a reverse connection protection circuit, and a current direction detection circuit. The output terminal of the POS machine power supply is connected to the input terminal of the current direction detection circuit and the input terminal of the reverse connection protection circuit. The output terminal of the current direction detection circuit is connected to the input terminal of the reverse connection protection circuit. The output terminal of the reverse connection protection circuit is connected to an output positive terminal and an output negative terminal. The output positive terminal and the output negative terminal can be connected to a charging power supply and the main control circuit board inside the POS machine. The reverse connection protection circuit is equipped with a field-effect transistor Q2, which is an NMOS transistor. The current direction detection circuit is equipped with a transistor Q1. In this embodiment, the reverse connection protection circuit can control the on / off state of the POS power supply output based on the positive and negative connection states of the output positive and negative terminals and the charging and discharging state of the POS power supply fed back by the current direction detection circuit. In other words, it can realize the reverse connection protection function of the POS power supply. The NMOS transistor with extremely low on-resistance is used as the reverse connection protection element of the POS power supply, which greatly reduces the circuit loss when the POS power supply is working. At the same time, a transistor amplifier circuit is used to detect the current direction during charging, thereby providing the reverse connection protection function of the battery during charging. The circuit structure is simple.
[0020] like Figure 1As shown, the reverse connection protection circuit also includes resistors R1 and R2. The gate of the field-effect transistor Q2 is connected to one end of resistor R1 and the output terminal of the current direction detection circuit. The other end of resistor R1 is connected to the positive terminal of the POS machine power supply, one end of resistor R2, and the output positive terminal. The source of the field-effect transistor Q2, the other end of resistor R2, and the output negative terminal are grounded to GND_2. The drain of the field-effect transistor Q2, the negative terminal of the POS machine power supply, and the input terminal of the current direction detection circuit are grounded to GND_1. The current direction detection circuit also includes resistors R3 and R4. The base of transistor Q1 is connected to one end of resistor R3 and one end of resistor R4. The other end of resistor R3 is grounded to GND_1, and the other end of resistor R4 and the emitter of transistor Q1 are grounded to GND_2. The collector of transistor Q1 is connected to the gate of field-effect transistor Q2 and one end of resistor R1. The resistance of resistor R1 is 10KΩ, the resistance of resistor R3 is 10KΩ, the resistance of resistor R4 is 10KΩ, the field-effect transistor Q2 is model AO3400A, and the POS machine power supply is a rechargeable lead-acid battery or a rechargeable lithium-ion battery. In this embodiment, when the POS power supply is discharging normally, after the POS power supply discharges through resistor R2, ground GND_2 will initially be about 0.4V higher than ground GND_1. At this time, the Vgs of the field-effect transistor Q2 is approximately the POS power supply voltage, so the field-effect transistor Q2 will be fully turned on, meaning the voltage difference between ground GND_2 and ground GND_1 is essentially zero, the POS power supply forms a power supply circuit, and the POS power supply operates normally. When the POS power supply is discharged in reverse connection, due to the presence of the parasitic diode between the drain and source terminals of the field-effect transistor Q2, the current of the POS power supply will not be able to pass through resistor R2, meaning the POS power supply will not discharge. When the POS power supply is charging normally, Charge+ and Charge- The voltage difference between the two terminals is approximately 4.2V. After the connection of R1, the Vgs voltage of Q2 is also approximately 4.2V. Thus, Q2 is fully conducting, and the positive output Charge+ and negative output Charge- form a circuit through the POS power supply, which can charge the POS power supply normally. When the POS power supply is reversed for charging, the voltage difference between ground GND_1 and ground GND_2 is approximately 4.2V + VBAT. In this case, transistor Q1 will conduct, and the Vgs voltage of field-effect transistor Q2 will be approximately 0V. That is, field-effect transistor Q2 will not conduct, and the positive output Charge+ and negative output Charge- cannot form a circuit through the POS power supply, thus failing to charge the POS power supply normally.
[0021] As can be seen from the above, this utility model provides a charging and discharging protection circuit for reverse connection protection of POS machine power supply. By setting up a POS machine power supply, a reverse connection protection circuit, and a current direction detection circuit that cooperate with each other in the charging and discharging protection circuit for reverse connection protection of POS machine power supply, the reverse connection protection circuit can control the on / off of the output of POS machine power supply according to the positive and negative connection status of the output positive and negative terminals and the charging and discharging status of POS machine power supply fed back by the current direction detection circuit. That is, it can realize the reverse connection protection function of POS machine power supply. Using an NMOS transistor with extremely low on-resistance as the reverse connection protection element of POS machine power supply greatly reduces the circuit loss when POS machine power supply is working. At the same time, a transistor amplifier circuit is used to detect the current direction during charging, thereby providing the reverse connection protection function during charging. The circuit structure is simple and solves the problems of high loss of diodes and inability of PMOS transistors to play a reverse connection protection role during charging in the existing POS machine power supply reverse connection protection circuit.
[0022] The specific embodiments described above are preferred embodiments of this utility model, and are not intended to limit the specific scope of this utility model. The scope of this utility model includes but is not limited to the specific embodiments described above. All equivalent changes made in accordance with this utility model are within the protection scope of this utility model.
Claims
1. A charging and discharging protection circuit for reverse connection protection of POS machine power supply, characterized in that: The system includes a POS machine power supply, a reverse connection protection circuit, and a current direction detection circuit. The output terminal of the POS machine power supply is connected to the input terminal of the current direction detection circuit and the input terminal of the reverse connection protection circuit. The output terminal of the current direction detection circuit is connected to the input terminal of the reverse connection protection circuit. The output terminal of the reverse connection protection circuit has a positive output terminal and a negative output terminal. The positive output terminal and the negative output terminal can be connected to a charging power supply and the main control circuit board inside the POS machine. The reverse connection protection circuit contains a field-effect transistor Q2, which is an NMOS transistor. The current direction detection circuit contains a transistor Q1. The reverse connection protection circuit can control the on / off state of the POS machine power supply output based on the positive / reverse connection state of the output positive and negative terminals and the charging / discharging state of the POS machine power supply fed back by the current direction detection circuit.
2. The charging and discharging protection circuit for reverse connection protection of POS machine power supply according to claim 1, characterized in that: The reverse connection protection circuit also includes resistors R1 and R2. The gate of the field-effect transistor Q2 is connected to one end of resistor R1 and the output terminal of the current direction detection circuit. The other end of resistor R1 is connected to the positive terminal of the POS machine power supply, one end of resistor R2 and the output positive terminal. The source of the field-effect transistor Q2, the other end of resistor R2 and the output negative terminal are grounded to GND_2. The drain of the field-effect transistor Q2, the negative terminal of the POS machine power supply and the input terminal of the current direction detection circuit are grounded to GND_1.
3. The charging and discharging protection circuit for reverse connection protection of POS machine power supply according to claim 2, characterized in that: The current direction detection circuit also includes resistors R3 and R4. The base of transistor Q1 is connected to one end of resistor R3 and one end of resistor R4. The other end of resistor R3 is grounded to GND_1. The other end of resistor R4 and the emitter of transistor Q1 are grounded to GND_2. The collector of transistor Q1 is connected to the gate of field-effect transistor Q2 and one end of resistor R1.
4. The charging and discharging protection circuit for reverse connection protection of POS machine power supply according to claim 3, characterized in that: The resistance of resistor R1 is 10KΩ.
5. The charging and discharging protection circuit for reverse connection protection of POS machine power supply according to claim 4, characterized in that: The resistance of resistor R3 is 10KΩ, and the resistance of resistor R4 is 10KΩ.
6. The charging and discharging protection circuit for reverse connection protection of POS machine power supply according to claim 5, characterized in that: The field-effect transistor Q2 is model AO3400A.
7. The charging and discharging protection circuit for reverse connection protection of POS machine power supply according to claim 6, characterized in that: The POS machine is powered by a rechargeable lead-acid battery or a rechargeable lithium-ion battery.