Communication interface circuit of fingerprint module

Abstract

The utility model discloses a communication interface circuit of a fingerprint module. The communication interface circuit comprises a USBDP pin, a USBDM pin, a UARTRXD pin, a UARTRXD pin and an EN pin of a 12-pin flat cable interface, wherein the USBDP pin, the USBDM pin, the UARTRXD pin, the UARTRXD pin and the EN pin are connected with the USBDP pin, the USBDM pin, the UARTRXD pin, the UARTRXD pin and the EN pin with corresponding functions of an 8-pin wire harness interface respectively; a first VCC pin and a second VCC pin of the 12-pin flat cable interface are jointly connected to a VCC pin of the 8-pin wire harness interface; a first GND pin, a second GND pin and a third GND pin of the 12-pin flat cable interface are jointly connected to a GND pin of the 8-pin wire harness; the first ESD pin and the second ESD pin of the 12-pin flat cable interface are connected to the ESD pin of the 8-pin wire harness together. Production and manufacturing are easy, and the production cost is low.

Description

Technical Field

[0001] This application relates to the field of fingerprint module technology, and in particular to a communication interface circuit for a fingerprint module. Background Technology

[0002] A fingerprint module is a biometric identification device that authenticates a user's identity by capturing and analyzing their fingerprint features. These modules typically integrate high-resolution sensors and sophisticated algorithms to accurately read fingerprint patterns and convert them into digital templates. In applications with high security requirements, such as mobile device unlocking, enterprise access control systems, and financial service verification, fingerprint modules provide a convenient, fast, and difficult-to-forge means of identity verification, enhancing security and simplifying the user authentication process.

[0003] Currently available fingerprint modules typically only come with one type of external communication connector. While this simplifies the design to some extent, it also limits their flexibility in diverse application scenarios. When the host computer or application device requires different connectors, manufacturers often need to design different PCB board types and connectors, which not only increases the complexity of manufacturing but also raises production costs and complicates inventory management. Summary of the Invention

[0004] Based on this, and in response to the aforementioned technical problems, a communication interface circuit for a fingerprint module is provided to solve the problem of complex manufacturing when designing different connector interfaces for existing fingerprint modules.

[0005] A communication interface circuit for a fingerprint module, the circuit comprising: a 12-pin ribbon cable interface, an 8-pin wire harness interface, resistors R14, R13, R10, R16, and R2.

[0006] The 12-pin ribbon cable interface includes a USB_DP pin, a USB_DM pin, a UART_RXD pin, a UART_TXD pin, an EN pin, a first VCC pin, a second VCC pin, a first GND pin, a second GND pin, a third GND pin, a first ESD pin, and a second ESD pin.

[0007] The 8-pin harness interface includes: USB_DP pin, USB_DM pin, UART_RXD pin, UART_TXD pin, EN pin, VCC pin, GND pin, and ESD pin;

[0008] The USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 12-pin ribbon cable interface are respectively connected to the corresponding USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 8-pin wire harness interface; the first VCC pin and the second VCC pin of the 12-pin ribbon cable interface are both connected to the VCC pin of the 8-pin wire harness interface; the first GND pin, the second GND pin, and the third GND pin of the 12-pin ribbon cable interface are both connected to the GND pin of the 8-pin wire harness; the first ESD pin and the second ESD pin of the 12-pin ribbon cable interface are both connected to the ESD pin of the 8-pin wire harness.

[0009] The USB_DP pin of the 8-pin harness is connected to one end of resistor R14, and the other end of resistor R14 is the USB_DP terminal of the internal circuit of the fingerprint module; the USB_DM pin of the 8-pin harness is connected to one end of resistor R13, and the other end of resistor R13 is the USB_DM terminal of the internal circuit of the fingerprint module; the UART_RXD pin of the 8-pin harness is connected to one end of resistor R16, and the other end of resistor R16 is the UART_RXD terminal of the internal circuit of the fingerprint module; the UART_TXD pin of the 8-pin harness is connected through one end of resistor R2, and the other end of resistor R2 is the UART_TXD terminal of the internal circuit of the fingerprint module; the EN pin of the 8-pin harness is connected to one end of resistor R10, and the other end of resistor R10 is the EN terminal of the internal circuit of the fingerprint module.

[0010] Optionally, in the above scheme, the 12-pin wire harness interface is located on the edge of the PCB board, and the 8-pin wire harness interface is located on the side of the 12-pin wire harness interface away from the edge of the PCB board.

[0011] Optionally, the circuit further includes: a first ESD anti-static protection circuit, a second ESD anti-static protection circuit, and a third ESD anti-static protection circuit.

[0012] One end of the first ESD anti-static protection circuit is connected to the connection line between the UART_RXD pin of the 8-pin wire harness interface and the resistor R16, and the other end is connected to GND.

[0013] One end of the second ESD protection circuit is connected to the connection line between the UART_TXD pin of the 8-pin harness interface and resistor R2, and the other end is connected to GND.

[0014] One end of the third ESD protection circuit is connected to the VCC pin of the 8-pin harness interface, and the other end is connected to GND.

[0015] In the above scheme, optionally, the first ESD anti-static protection circuit is a transient voltage suppression diode D19, the second ESD anti-static protection circuit is a transient voltage suppression diode D18, and the third ESD anti-static protection circuit is a transient voltage suppression diode D14.

[0016] Optionally, in the above scheme, the transient voltage suppression diodes D19, D18, and D14 are model BTR04G3.

[0017] In the above scheme, optionally, the resistance of resistor R14 is 0 ohms, the resistance of resistor R13 is 0 ohms, the resistance of resistor R16 is 33 ohms, and the resistance of resistor R2 is 33 ohms.

[0018] This application has at least the following beneficial effects:

[0019] This application presents a 12-pin ribbon cable interface and an 8-pin wire harness interface, both with USB_DP and USB_DM pins, as well as UART_RXD and UART_TXD pins, enabling the communication interface to support both USB and UART communication. This allows for adaptation to various communication environments; for example, data transmission can be performed via UART while charging via USB. Furthermore, the USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 12-pin ribbon cable interface are connected to the corresponding functional pins in the 8-pin wire harness. The first and second VCC pins of the 12-pin ribbon cable interface are connected to the VCC pin of the 8-pin ribbon cable interface. Similarly, the first, second, and third GND pins of the 12-pin ribbon cable interface are connected to the GND pin of the 8-pin ribbon cable interface, and the first and second ESD pins of the 12-pin ribbon cable interface are connected to the ESD pin of the 8-pin ribbon cable interface. This allows the fingerprint module to communicate via either the 12-pin ribbon cable interface or the 8-pin wire harness interface. Moreover, this application uses only one PCB board type, which simplifies manufacturing, reduces production costs, and makes inventory preparation easier.

[0020] This application also incorporates ESD protection circuits for serial ports UART_RXD and UART_TXD and a 5V power supply. Since fingerprint modules are electronic components that fingers frequently come into contact with, adding ESD protection circuits can effectively protect the fingerprint module itself and the entire device, extending the device's lifespan. Attached Figure Description

[0021] Figure 1A schematic diagram of the communication interface circuit of a fingerprint module provided in one embodiment of this application;

[0022] Figure 2 This is a diagram showing the layout of a 12-pin ribbon cable interface and an 8-pin wire harness interface on a PCB board according to an embodiment of this application.

[0023] in, Figure 1 In the pinout, 1 is the USB_DP pin of the 12-pin ribbon cable interface, 2 is the USB_DM pin of the 12-pin ribbon cable interface, 3 is the UART_RXD pin of the 12-pin ribbon cable interface, 4 is the UART_TXD pin of the 12-pin ribbon cable interface, 5 is the EN pin of the 12-pin ribbon cable interface, 6 is the first VCC pin of the 12-pin ribbon cable interface, 7 is the second VCC pin of the 12-pin ribbon cable interface, 8 is the first GND pin of the 12-pin ribbon cable interface, 9 is the second GND pin of the 12-pin ribbon cable interface, 10 is the third GND pin of the 12-pin ribbon cable interface, 11 is the first ESD pin of the 12-pin ribbon cable interface, and 12 is the second ESD pin of the 12-pin ribbon cable interface.

[0024] 13 is the USB_DP pin of the 8-pin harness interface, 14 is the USB_DM pin of the 8-pin harness interface, 15 is the UART_RXD pin of the 8-pin harness interface, 16 is the UART_TXD pin of the 8-pin harness interface, 17 is the EN pin of the 8-pin harness interface, 18 is the VCC pin of the 8-pin harness interface, 19 is the GND pin of the 8-pin harness interface, and 20 is the ESD pin of the 8-pin harness interface. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "comprising," "including," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0027] In one embodiment, such as Figure 1As shown, a communication interface circuit for a fingerprint module is provided. The circuit includes: a 12-pin ribbon cable interface, an 8-pin wire harness interface, resistors R14, R13, R16, and R2.

[0028] The 12-pin ribbon cable interface includes a USB_DP pin, a USB_DM pin, a UART_RXD pin, a UART_TXD pin, an EN pin, a first VCC pin, a second VCC pin, a first GND pin, a second GND pin, a third GND pin, a first ESD pin, and a second ESD pin.

[0029] The 8-pin harness interface includes: USB_DP pin, USB_DM pin, UART_RXD pin, UART_TXD pin, EN pin, VCC pin, GND pin, and ESD pin;

[0030] The USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 12-pin ribbon cable interface are respectively connected to the corresponding USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 8-pin wire harness interface; the first VCC pin and the second VCC pin of the 12-pin ribbon cable interface are both connected to the VCC pin of the 8-pin wire harness interface; the first GND pin, the second GND pin, and the third GND pin of the 12-pin ribbon cable interface are both connected to the GND pin of the 8-pin wire harness; the first ESD pin and the second ESD pin of the 12-pin ribbon cable interface are both connected to the ESD pin of the 8-pin wire harness.

[0031] The USB_DP pin of the 8-pin harness is connected to one end of resistor R14, and the other end of resistor R14 is the USB_DP terminal of the internal circuit of the fingerprint module; the USB_DM pin of the 8-pin harness is connected to one end of resistor R13, and the other end of resistor R13 is the USB_DM terminal of the internal circuit of the fingerprint module; the UART_RXD pin of the 8-pin harness is connected to one end of resistor R16, and the other end of resistor R16 is the UART_RXD terminal of the internal circuit of the fingerprint module; the UART_TXD pin of the 8-pin harness is connected through one end of resistor R2, and the other end of resistor R2 is the UART_TXD terminal of the internal circuit of the fingerprint module; the EN pin of the 8-pin harness is connected to one end of resistor R10, and the other end of resistor R10 is the EN terminal of the internal circuit of the fingerprint module.

[0032] Meanwhile, the fingerprint module conforming to the Ministry of Public Security specifications in this application supports both USB communication and high-speed serial communication, which can effectively solve the problem of integrating fingerprint collection functions into PDAs or tablets and meet the requirements of long-term use in all-weather office environments. In USB charging mode, fingerprint image acquisition and verification are not affected in any way. Moreover, the fingerprint module's serial port supports high-speed 921600bps, which is 8 times faster than the traditional 115200bps, resulting in fast and efficient fingerprint image transmission.

[0033] In the communication interface circuit of the aforementioned fingerprint module, the 12-pin ribbon cable interface and the 8-pin harness interface of this application have both USB_DP and USB_DM pins, as well as UART_RXD and UART_TXD pins, enabling the communication interface to support both USB and UART communication. This allows it to adapt to various communication environments; for example, data transmission can be performed using UART while charging via USB. Simultaneously, the USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 12-pin ribbon cable interface are connected to the corresponding functional pins in the 8-pin harness. The first and second VCC pins of the 12-pin ribbon cable interface are connected to the VCC pin of the 8-pin ribbon cable interface. The first, second, and third GND pins of the 12-pin ribbon cable interface are connected to the GND pin of the 8-pin ribbon cable interface. The first and second ESD pins of the 12-pin ribbon cable interface are connected to the ESD pin of the 8-pin ribbon cable interface. This allows the fingerprint module to communicate via either a 12-pin ribbon cable interface or an 8-pin wire harness interface. Furthermore, this application uses only a single PCB board, simplifying manufacturing, reducing production costs, and making inventory preparation easier.

[0034] In one embodiment, the 12-pin harness interface is located at the edge of the PCB board, and the 8-pin harness interface is located on the side of the 12-pin harness interface away from the edge of the PCB board.

[0035] In this embodiment, such as Figure 2 As shown, the PCB design includes two interface packages: a 12-pin package and an 8-pin package. Both packages include a USB interface and a serial port. The 12-pin flat ribbon cable interface is small and located at the edge of the PCB board, while the 8-pin wire harness interface is larger and located on the inner edge of the PCB board. This design ensures that the solder pads do not overlap and allows for flexible soldering according to customer needs.

[0036] In one embodiment, the circuit further includes: a first ESD anti-static protection circuit, a second ESD anti-static protection circuit, and a third ESD anti-static protection circuit.

[0037] One end of the first ESD anti-static protection circuit is connected to the connection line between the UART_RXD pin of the 8-pin wire harness interface and the resistor R16, and the other end is connected to GND.

[0038] One end of the second ESD protection circuit is connected to the connection line between the UART_TXD pin of the 8-pin harness interface and the resistor R2, and the other end is connected to GND.

[0039] One end of the third ESD protection circuit is connected to the VCC (5V) pin of the 8-pin harness interface, and the other end is connected to GND.

[0040] In one embodiment, the first ESD protection circuit is a transient voltage suppression diode D19, the second ESD protection circuit is a transient voltage suppression diode D18, and the third ESD protection circuit is a transient voltage suppression diode D14.

[0041] Specifically, a serial port circuit has been added to the commonly used USB interface, along with ESD protection circuits for the UART_RXD and UART_TXD serial ports and the 5V power supply. Since PDAs or tablets are handheld devices, static electricity is prone to occur in dry seasons such as autumn and winter in northern regions. The fingerprint module is an electronic component that fingers frequently come into contact with. Adding the anti-static protection circuit can effectively protect the fingerprint module itself and the entire device, extending the device's lifespan.

[0042] In one embodiment, the transient voltage suppression diodes D19, D18, and D14 are of type BTR04G3.

[0043] In one embodiment, the resistance of resistor R14 is 0 ohms, the resistance of resistor R13 is 0 ohms, the resistance of resistor R16 is 33 ohms, and the resistance of resistor R2 is 33 ohms.

[0044] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A communication interface circuit for a fingerprint module, characterized in that, The circuit includes: a 12-pin ribbon cable interface, an 8-pin wire harness interface, resistors R14, R13, R10, R16, and R2. The 12-pin ribbon cable interface includes a USB_DP pin, a USB_DM pin, a UART_RXD pin, a UART_TXD pin, an EN pin, a first VCC pin, a second VCC pin, a first GND pin, a second GND pin, a third GND pin, a first ESD pin, and a second ESD pin. The 8-pin harness interface includes: USB_DP pin, USB_DM pin, UART_RXD pin, UART_TXD pin, EN pin, VCC pin, GND pin, and ESD pin; The USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 12-pin ribbon cable interface are respectively connected to the corresponding USB_DP, USB_DM, UART_RXD, UART_TXD, and EN pins of the 8-pin wire harness interface; the first VCC pin and the second VCC pin of the 12-pin ribbon cable interface are both connected to the VCC pin of the 8-pin wire harness interface; the first GND pin, the second GND pin, and the third GND pin of the 12-pin ribbon cable interface are both connected to the GND pin of the 8-pin wire harness; the first ESD pin and the second ESD pin of the 12-pin ribbon cable interface are both connected to the ESD pin of the 8-pin wire harness. The USB_DP pin of the 8-pin harness is connected to one end of resistor R14, and the other end of resistor R14 is the USB_DP terminal of the internal circuit of the fingerprint module; the USB_DM pin of the 8-pin harness is connected to one end of resistor R13, and the other end of resistor R13 is the USB_DM terminal of the internal circuit of the fingerprint module; the UART_RXD pin of the 8-pin harness is connected to one end of resistor R16, and the other end of resistor R16 is the UART_RXD terminal of the internal circuit of the fingerprint module; the UART_TXD pin of the 8-pin harness is connected through one end of resistor R2, and the other end of resistor R2 is the UART_TXD terminal of the internal circuit of the fingerprint module; the EN pin of the 8-pin harness is connected to one end of resistor R10, and the other end of resistor R10 is the EN terminal of the internal circuit of the fingerprint module.

2. The communication interface circuit of the fingerprint module according to claim 1, characterized in that, The 12-pin ribbon cable interface is located on the edge of the PCB board, and the 8-pin wire harness interface is located on the side of the 12-pin ribbon cable interface away from the edge of the PCB board.

3. The communication interface circuit of the fingerprint module according to claim 1, characterized in that, The circuit further includes: a first ESD anti-static protection circuit, a second ESD anti-static protection circuit, and a third ESD anti-static protection circuit. One end of the first ESD anti-static protection circuit is connected to the connection line between the UART_RXD pin of the 8-pin wire harness interface and the resistor R16, and the other end is connected to GND. One end of the second ESD protection circuit is connected to the connection line between the UART_TXD pin of the 8-pin harness interface and the resistor R2, and the other end is connected to GND. One end of the third ESD protection circuit is connected to the VCC pin of the 8-pin harness interface, and the other end is connected to GND.

4. The communication interface circuit of the fingerprint module according to claim 3, characterized in that, The first ESD protection circuit is a transient voltage suppression diode D19, the second ESD protection circuit is a transient voltage suppression diode D18, and the third ESD protection circuit is a transient voltage suppression diode D14.

5. The communication interface circuit of the fingerprint module according to claim 4, characterized in that, The transient voltage suppression diodes D19, D18, and D14 are model BTR04G3.

6. The communication interface circuit of the fingerprint module according to claim 1, characterized in that, The resistance of resistor R14 is 0 ohms, the resistance of resistor R13 is 0 ohms, the resistance of resistor R16 is 33 ohms, and the resistance of resistor R2 is 33 ohms.

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