IC card reader interface circuit

Abstract

The utility model relates to the field of IC card readers, in particular to an IC card reader interface circuit, which is characterized in that a third pin to a sixth pin of an isolation transceiver are respectively connected with a controller through a fourth resistor, a third resistor, a second resistor and a first resistor, the second pin of the isolation transceiver is grounded, the first pin of the isolation transceiver is grounded through a first capacitor, and the second pin of the isolation transceiver is grounded through a second capacitor. The seventh pin and the eighth pin are respectively connected with the eighth pin and the seventh pin of the first connector, and the ninth pin and the tenth pin are respectively connected with the fourth pin and the third pin of the first connector. The seventh pin to the tenth pin are respectively grounded through a first transient suppression diode, a second transient suppression diode, a third transient suppression diode and a fourth transient suppression diode, a first pin of the first connector is respectively connected with cathodes of a first voltage stabilizing diode and a second voltage stabilizing diode through a fifth resistor, and an anode of the first connector is grounded. According to the utility model, electrical isolation between the controller and the interface is realized, and the safety and anti-interference capability of equipment are improved.

Description

Technical Field

[0001] The utility model relates to the field of IC card readers, and particularly to an IC card reader interface circuit. Background Art

[0002] An IC card reader is a device used to identify and read information on a smart card, and is widely used in various automated and intelligent devices and systems. The IC card reader can quickly and accurately identify the user's identity information and account balance, thereby realizing various automated and intelligent information services.

[0003] However, the current IC card reader interface circuit cannot achieve electrical isolation between the controller and the interface, resulting in low security and poor anti-interference ability. Summary of the Utility Model

[0004] The purpose of the utility model is to overcome the shortcomings of the prior art and provide an IC card reader interface circuit, which realizes electrical isolation between the controller and the interface, and improves the security and anti-interference ability of automated and intelligent devices.

[0005] The present utility model adopts the following technical solutions to achieve the above object. The present utility model provides an IC card reader interface circuit, including an isolation transceiver U403, a first transient suppression diode T403, a second transient suppression diode T404, a third transient suppression diode T405, a fourth transient suppression diode T406, a first voltage stabilizing diode T412, a second voltage stabilizing diode T413, a first resistor R420, a second resistor R421, a third resistor R422, a fourth resistor R423, a fifth resistor R416, a sixth resistor R417, a first capacitor C401, a first connector CON8 and a controller. The third to sixth pins of the isolation transceiver U403 are respectively connected to the controller through the fourth resistor R423, the third resistor R422, the second resistor R421 and the first resistor R420. The second pin of the isolation transceiver U403 is grounded, and the first pin is grounded through the first capacitor C401. The seventh and eighth pins of the isolation transceiver U403 are respectively connected to the eighth and seventh pins of the first connector CON8. The ninth and tenth pins of the isolation transceiver U403 are respectively connected to the fourth and third pins of the first connector CON8. The seventh to tenth pins of the isolation transceiver U403 are respectively grounded through the first transient suppression diode T403, the second transient suppression diode T404, the third transient suppression diode T405 and the fourth transient suppression diode T406. The first pin of the first connector CON8 is connected to the 12V power supply through the fifth resistor R416 and is respectively connected to the cathodes of the first voltage stabilizing diode T412 and the second voltage stabilizing diode T413. The anodes of the first voltage stabilizing diode T412 and the second voltage stabilizing diode T413 are grounded. The fifth pin of the first connector CON8 is connected to the 12V power supply through the sixth resistor R417.

[0006] Further, the model of the isolation transceiver U403 is TD302D232H.

[0007] Further, the models of the first transient suppression diode T403, the second transient suppression diode T404, the third transient suppression diode T405 and the fourth transient suppression diode T406 are SMF15CA.

[0008] Further, the models of the first voltage stabilizing diode T412 and the second voltage stabilizing diode T413 are 1SMB5927B.

[0009] Further, the model of the controller is GD32F450.

[0010] The beneficial effects of the present utility model:

[0011] An isolation transceiver is added between the controller and the connector interface in the present utility model. Electrical isolation between the controller and the connector interface is achieved through the isolation transceiver, improving the safety and anti-interference ability of automated and intelligent devices. Description of the Drawings

[0012] Figure 1 It is a circuit structure diagram of the controller provided by an embodiment of the present utility model;

[0013] Figure 2 It is a schematic diagram of the IC card reader interface circuit provided by an embodiment of the present utility model;

[0014] Figure 3 It is a schematic diagram of the first connector circuit provided by an embodiment of the present utility model. Detailed Implementation Manner

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model.

[0016] The present utility model provides an IC card reader interface circuit, such as Figure 1 , Figure 2 , Figure 3As shown in the figure, it includes an isolation transceiver U403, a first transient suppression diode T403, a second transient suppression diode T404, a third transient suppression diode T405, a fourth transient suppression diode T406, a first voltage regulator diode T412, a second voltage regulator diode T413, a first resistor R420, a second resistor R421, a third resistor R422, a fourth resistor R423, a fifth resistor R416, a sixth resistor R417, a first capacitor C401, a first connector CON8 and a controller. The third to sixth pins of the isolation transceiver U403 are respectively connected to the ninety-sixth and ninety-seventh pins of the controller through the fourth resistor R423, the third resistor R422, the second resistor R421, and the first resistor R420. The second pin of the isolation transceiver U403 is grounded, and the first pin is grounded through the first capacitor C401. The seventh and eighth pins of the isolation transceiver U403 are respectively connected to the eighth and seventh pins of the first connector CON8. The ninth and tenth pins of the isolation transceiver U403 are respectively connected to the fourth and third pins of the first connector CON8. The seventh to tenth pins of the isolation transceiver U403 are respectively grounded through the first transient suppression diode T403, the second transient suppression diode T404, the third transient suppression diode T405, and the fourth transient suppression diode T406. The first pin of the first connector CON8 is connected to the 12V power supply through the fifth resistor R416 and is respectively connected to the cathodes of the first voltage regulator diode T412 and the second voltage regulator diode T413. The anodes of the first voltage regulator diode T412 and the second voltage regulator diode T413 are grounded. The fifth pin of the first connector CON8 is connected to the 12V power supply through the sixth resistor R417.

[0017] Specifically, the controller uses GD32F450 from GigaDevice as the main controller. GD32F450 has ultra-high computing performance. The highest main frequency of the processor can reach 200MHz, and it provides a complete DSP instruction set, parallel computing ability and a dedicated floating-point unit FPU, so as to integrate 32-bit control and leading digital signal processing technology to meet advanced computing requirements. Execute code directly in the flash with zero wait state. GD32F450 is equipped with 512KB to 3072KB of on-chip Flash and 256KB to 512KB of SRAM. The dual-bank flash allows synchronous read and write operations, which facilitates safe program upgrade and does not affect application performance while updating the software.

[0018] The peripheral interface resources include 8 USARTs, 6 SPIs, 3 fast I2Cs, 2 I2Ss, 2 CAN2.0Bs, 1 SDIO interface, 1 10 / 100M Ethernet controller MAC, and for the first time, two USB2.0 OTG interfaces are equipped, including Full Speed, 12Mbps and High Speed, 480Mbps interfaces, which can provide multiple transmission modes such as Device, HOST, and OTG.

[0019] Specifically, the model of the isolation transceiver U403 is TD302D232H. TD502D232H is a high-speed dual-channel isolated RS-232 transceiver suitable for bidirectional data communication, with a maximum baud rate of up to 115200bps. An isolated DC / DC converter is integrated inside the transceiver, and only a single power supply is required to achieve electrical isolation between the controller and the RS-232 transceiver. The maximum isolation voltage reaches 2500VDC, and there is no need to configure an additional isolation power supply, which is convenient for users to apply.

[0020] Specifically, the models of the first transient suppression diode T403, the second transient suppression diode T404, the third transient suppression diode T405, and the fourth transient suppression diode T406 are SMF15CA. The transient suppression diode mainly realizes overvoltage protection and can protect electrical equipment from voltage spikes introduced by wires. When its two poles are subjected to a reverse transient high-energy impact, it can change the high impedance between the two poles to a low impedance at the nanosecond level, absorb the surge power at the same time, and clamp the voltage between the two poles to a safe value, thus effectively protecting the subsequent circuit devices from being damaged by surge pulses. Through the above four transient suppression diodes, surge protection for the rear-end isolation transceiver U403 is achieved, ensuring the reliable operation of the IC card reader in a harsh industrial field environment.

[0021] Specifically, the models of the first voltage regulator diode T412 and the second voltage regulator diode T413 are 1SMB5927B. The voltage regulator diode mainly realizes voltage regulation and surge protection functions. By utilizing the Zener breakdown characteristic of the diode, the voltage regulator diode can provide a stable voltage in the circuit and protect the circuit from voltage fluctuations. The voltage regulator diode uses the reverse breakdown state of the PN junction to achieve its voltage regulation function. When the reverse voltage is lower than the reverse breakdown voltage, the reverse resistance value of the voltage regulator diode is very large, and the reverse leakage current is extremely small. When the reverse voltage approaches the critical value of the reverse breakdown voltage, the reverse current will suddenly increase, generating an avalanche effect and entering the breakdown state. At this time, the current change of the voltage regulator diode is very large, but the voltage across the two ends is basically stable near the breakdown voltage, thus realizing the voltage regulation function of the diode. Through the two voltage regulator diodes, the stable and reliable 12V power supply voltage can be ensured.

[0022] Working principle of the present utility model:

[0023] When the main controller needs to read and write the IC card, a signal is first sent through the serial interface USART of the main controller. The signal is first transmitted to the isolation transceiver and then transmitted to the subsequent circuit after isolation. The isolation transceiver realizes the electrical isolation between the controller and the connector interface, avoiding the influence of on-site interference signals on the main controller to ensure the reliable operation of the main controller.

[0024] The isolated signal is further transmitted to the on-site card reader. When the card reader detects a legal IC card, the information in the IC card can be read out, and then the IC information is transmitted to the main controller for operation or judgment through the above data link, and various signals are output according to the preset program.

[0025] The above is only the preferred embodiment of the present utility model. It should be understood that the present utility model is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in the relevant field. And the changes and alterations made by those skilled in the art without departing from the spirit and scope of the present utility model shall fall within the protection scope of the appended claims of the present utility model.

Claims

1. An IC card reader interface circuit, characterized in that, It includes an isolation transceiver (U403), a first transient suppression diode (T403), a second transient suppression diode (T404), a third transient suppression diode (T405), a fourth transient suppression diode (T406), a first voltage regulator diode (T412), a second voltage regulator diode (T413), a first resistor (R420), a second resistor (R421), a third resistor (R422), a fourth resistor (R423), a fifth resistor (R416), a sixth resistor (R417), a first capacitor (C401), a first connector (CON8) and a controller. The third to sixth pins of the isolation transceiver (U403) are respectively connected to the controller through the fourth resistor (R423), the third resistor (R422), the second resistor (R421) and the first resistor (R420). The second pin of the isolation transceiver (U403) is grounded, and the first pin is grounded through the first capacitor (C401). The seventh and eighth pins of the isolation transceiver (U403) are respectively connected to the eighth and seventh pins of the first connector (CON8). The ninth and tenth pins of the isolation transceiver (U403) are respectively connected to the fourth and third pins of the first connector (CON8). The seventh to tenth pins of the isolation transceiver (U403) are respectively grounded through the first transient suppression diode (T403), the second transient suppression diode (T404), the third transient suppression diode (T405) and the fourth transient suppression diode (T406). The first pin of the first connector (CON8) is connected to the 12V power supply through the fifth resistor (R416) and is respectively connected to the cathodes of the first voltage regulator diode (T412) and the second voltage regulator diode (T413). The anodes of the first voltage regulator diode (T412) and the second voltage regulator diode (T413) are grounded. The fifth pin of the first connector (CON8) is connected to the 12V power supply through the sixth resistor (R417).

2. The IC card reader interface circuit according to claim 1, characterized in that, The model of the isolation transceiver (U403) is TD302D232H.

3. The IC card reader interface circuit according to claim 1, characterized in that, The models of the first transient suppression diode (T403), the second transient suppression diode (T404), the third transient suppression diode (T405) and the fourth transient suppression diode (T406) are SMF15CA.

4. The IC card reader interface circuit according to claim 1, wherein The models of the first voltage regulator diode (T412) and the second voltage regulator diode (T413) are 1SMB5927B.

5. The IC card reader interface circuit according to claim 1, characterized in that, The model of the controller is GD32F450.

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