Charging thimble power supply soft start circuit of POS machine charging landline

Abstract

The utility model discloses a charging thimble power supply soft start circuit of a POS machine charging landline, one end of a resistor R1 is connected with a VCC, the other end of the resistor R1 is connected with an R2, and the other end of the R2 is grounded; a positive power supply pin of the operational amplifier U1 is connected with VCC, a negative power supply pin of the operational amplifier U1 is grounded, a reverse input end of the operational amplifier U1 is connected to a common end between the R1 and the R2, a non-inverting input end of the operational amplifier U1 is connected with the R3, the other end of the R3 is connected with a drain electrode of the N-MOS tube Q1, an output end of the operational amplifier U1 is connected with the R4, the other end of the operational amplifier U1 is connected with a grid electrode of the N-MOS tube Q1, and a source electrode of the N-MOS tube Q1 is grounded. One end of the capacitor C2 is connected to a common end between the R4 and the grid electrode of the N-MOS tube Q1, and the other end of the capacitor C2 is grounded; the charging ejector pin A1 is connected with a power supply VCC, the charging ejector pin A2 is connected to a common end D between the resistor R3 and the drain electrode of the N-MOS tube Q1, one end of the resistor R5 is connected to a common end between the common end D and the charging ejector pin A2, and the other end of the resistor R5 is grounded. The circuit can effectively avoid the situation that the charging ejector pin is damaged due to the fact that large current is generated at the moment of POS charging.

Description

Technical Field

[0001] This utility model relates to the field of POS machine charging technology, and in particular to a soft-start circuit for the charging pin of a POS machine charging base. Background Technology

[0002] As a popular payment device, POS machines are typically charged using a matching charging dock. Currently, the two charging pins of the charging dock are always powered, while the voltage at the POS machine's charging port is zero. When the POS machine is placed on the dock, a large current is instantly generated, causing the charging pins to be easily damaged by the high current surge. Utility Model Content

[0003] To address the aforementioned problems, the purpose of this utility model is to propose a soft-start circuit for the charging pin of a POS machine charging stand. When the POS machine is placed on the charging stand, the charging pin of the charging stand is powered on to charge the POS machine, preventing the pin from being damaged by a large current surge immediately during charging.

[0004] To achieve the above-mentioned technical objectives, the technical solution adopted by this utility model is as follows: a soft-start circuit for the charging pin of a POS machine charging base, including resistors R1, R2, R3, R4, R5, operational amplifier U1, N-MOS transistor Q1, capacitor C2, charging pin A1 and charging pin A2.

[0005] One end of resistor R1 is connected to power supply VCC, and the other end is connected to resistor R2. The other end of resistor R2 is grounded.

[0006] The positive power supply pin of the operational amplifier U1 is connected to the power supply VCC, and the negative power supply pin is grounded. The inverting input terminal of the operational amplifier U1 is connected to the common terminal between resistors R1 and R2. The non-inverting input terminal of the operational amplifier U1 is connected to resistor R3, and the other end of resistor R3 is connected to the drain of N-MOS transistor Q1. The output terminal of the operational amplifier U1 is connected to resistor R4, and the other end of resistor R4 is connected to the gate of N-MOS transistor Q1. The source of N-MOS transistor Q1 is grounded. One end of capacitor C2 is connected to the common terminal between resistor R4 and the gate of N-MOS transistor Q1, and the other end of capacitor C2 is grounded.

[0007] The charging pin A1 is connected to the power supply VCC, the charging pin A2 is connected to the common terminal D between the resistor R3 and the drain of the N-MOS transistor Q1, one end of the resistor R5 is connected to the common terminal between the common terminal D and the charging pin A2, and the other end of the resistor R5 is grounded.

[0008] As one possible implementation, the power soft-start circuit of the charging pin of the POS machine charging base further includes: a capacitor C1, one end of which is connected to the common terminal between the charging pin A1 and the power supply VCC, and the other end of which is grounded.

[0009] By adopting the above technical solution, the beneficial effects of this utility model compared with the prior art are as follows:

[0010] This invention uses an operational amplifier to collect the voltage of the charging pin A2. When the POS terminal is placed on the charging base, the internal circuitry of the POS terminal causes the voltage of the charging pin A2 to rise. When the voltage of the charging pin A2 becomes sufficiently high, the operational amplifier outputs a high level. This high-level signal is filtered by resistor R4 and capacitor C2, becoming a slowly rising voltage that slowly turns on the N-MOS transistor Q1 to charge the POS terminal. This avoids the generation of a large instantaneous current during POS charging, which could easily damage the charging pin, thus extending its service life. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of 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 only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a circuit connection diagram of this utility model.

[0013] In the attached diagram, the labels refer to: C1. Capacitor, C2. Capacitor, R1. Resistor, R2. Resistor, R3. Resistor, R4. Resistor, R5. Resistor, U1. Operational amplifier, Q1. N-MOS transistor, A1. Charging pin, A2. Charging pin. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are only for illustrating the present invention and do not limit the scope of the present invention. Similarly, the following embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0015] See attached document Figure 1As shown, this embodiment provides a soft-start circuit for the charging pin of a POS machine charging base, including resistors R1, R2, R3, R4, R5, operational amplifier U1, N-MOS transistor Q1, capacitor C2, charging pin A1, charging pin A2 and capacitor C1.

[0016] One end of resistor R1 is connected to the power supply VCC, and the other end is connected to resistor R2. The other end of resistor R2 is grounded.

[0017] The positive power supply pin of operational amplifier U1 is connected to power supply VCC, the negative power supply pin is grounded, the inverting input terminal of operational amplifier U1 is connected to the common terminal between resistors R1 and R2, the non-inverting input terminal of operational amplifier U1 is connected to resistor R3, the other end of resistor R3 is connected to the drain of N-MOS transistor Q1, the output terminal of operational amplifier U1 is connected to resistor R4, the other end of resistor R4 is connected to the gate of N-MOS transistor Q1, the source of N-MOS transistor Q1 is grounded, one end of capacitor C2 is connected to the common terminal between resistor R4 and the gate of N-MOS transistor Q1, and the other end of capacitor C2 is grounded.

[0018] Charging pin A1 is connected to power supply VCC. Charging pin A2 is connected to the common terminal D between resistor R3 and the drain of N-MOS transistor Q1. One end of resistor R5 is connected to the common terminal D between charging pin A2 and charging pin A2, and the other end of resistor R5 is grounded. One end of capacitor C1 is connected to the common terminal between charging pin A1 and power supply VCC, and the other end of capacitor C1 is grounded. Capacitor C1 acts as a filter to stabilize the output voltage of power supply VCC.

[0019] In this embodiment, A1 and A2 are the two charging pins of the charging base for charging the POS terminal. Resistors R1 and R2 divide the power supply VCC to generate a small voltage, which is then connected to the negative input (inverting input) of operational amplifier U1 as a reference voltage. Charging pin A2 is connected to the positive input (non-inverting input) of operational amplifier U1 through resistor R3. When the POS terminal is placed on the charging base, the internal circuit of the POS terminal causes the voltage of charging pin A2 to rise, thereby raising the positive input voltage of operational amplifier U1. When the positive input voltage of operational amplifier U1 is higher than the negative input voltage, operational amplifier U1 will output a high voltage. After the high-level signal is filtered by resistor R4 and capacitor C2, it becomes a slowly rising voltage, causing N-MOS transistor Q1 to slowly conduct and charge the POS terminal. The function of resistor R5 is to ensure that resistor A2 is at a low level when the POS terminal is not placed on the charging base, thus ensuring that N-MOS transistor Q1 is in the off state.

[0020] Because the charging station only slowly turns on the power to charge the POS machine after it is placed on it, it avoids the charging pins from being easily damaged by a large current surge, thus extending the lifespan of the charging station.

[0021] The above description is only a part of the embodiments of this utility model, and does not limit the scope of protection of this utility model. Any equivalent device or equivalent process transformation made based on the content of this utility model specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this utility model.

Claims

1. A soft-start circuit for the charging pin of a POS machine charging base, characterized in that, Including resistors R1, R2, R3, R4, R5, operational amplifier U1, N-MOS transistor Q1, capacitor C2, charging pin A1 and charging pin A2; One end of resistor R1 is connected to power supply VCC, and the other end is connected to resistor R2. The other end of resistor R2 is grounded. The positive power supply pin of the operational amplifier U1 is connected to the power supply VCC, and the negative power supply pin is grounded. The inverting input terminal of the operational amplifier U1 is connected to the common terminal between resistors R1 and R2. The non-inverting input terminal of the operational amplifier U1 is connected to resistor R3, and the other end of resistor R3 is connected to the drain of N-MOS transistor Q1. The output terminal of the operational amplifier U1 is connected to resistor R4, and the other end of resistor R4 is connected to the gate of N-MOS transistor Q1. The source of N-MOS transistor Q1 is grounded. One end of capacitor C2 is connected to the common terminal between resistor R4 and the gate of N-MOS transistor Q1, and the other end of capacitor C2 is grounded. The charging pin A1 is connected to the power supply VCC, the charging pin A2 is connected to the common terminal D between the resistor R3 and the drain of the N-MOS transistor Q1, one end of the resistor R5 is connected to the common terminal between the common terminal D and the charging pin A2, and the other end of the resistor R5 is grounded.

2. The soft-start circuit for the charging pin power supply of the POS machine charging base according to claim 1, characterized in that, It also includes a capacitor C1, one end of which is connected to the common terminal between the charging pin A1 and the power supply VCC, and the other end of the capacitor C1 is grounded.

Images