4 serial port converter for automatic test bench
By using the FT4232HL chip and related circuit design, the interface mismatch problem of the automatic test bench for set-top boxes was solved, realizing the USB to serial port function and electrostatic protection, which is suitable for set-top box test benches.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIHAI BROADCASTING TECHNOLOGY CO LTD
- Filing Date
- 2025-08-05
- Publication Date
- 2026-06-05
AI Technical Summary
The automatic test bench for the set-top box requires four RS232 level interfaces, but these are not compatible with the product's level, resulting in an interface mismatch problem.
Using the FT4232HL chip, ESD protection circuit, filtering circuit, and USB interface, a USB to serial port function is implemented, which is compatible with the TTL level standard. The FT4232HL chip converts the USB protocol data output from the USB interface into TTL serial port data. Combined with the ESD protection circuit and filtering circuit, stable level compatibility and electrostatic protection are provided.
It achieves good compatibility with product voltage levels, provides electrostatic protection, and is smaller than existing products, making it easy to integrate into test computers.
Smart Images
Figure CN224328415U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of serial port converter technology, specifically to a 4-serial port converter for an automatic test bench. Background Technology
[0002] A serial port converter is a device used to convert between different serial port types or interface standards. Its main function is to solve the problem of interface incompatibility between devices and enable normal data communication. Currently, the automatic test bench for set-top boxes has four interfaces, requiring four boards, and can only use RS232 level. This is not compatible with the product's level in actual use. Therefore, a four-serial port converter with good level compatibility is needed. Utility Model Content
[0003] The purpose of this invention is to address the above-mentioned problems by providing a 4-serial-port converter for an automatic test bench, which enables USB to serial port conversion, is compatible with TTL level standards, and has good compatibility with product level.
[0004] To achieve the above objectives, the present invention adopts the following technical solution: a 4-serial-port converter for an automatic test bench, comprising an FT4232HL chip, an ESD protection circuit, a filtering circuit, a USB interface, and 4 serial ports; the data transmission port of the FT4232HL chip is connected to the USB interface, the input voltage port of the FT4232HL chip is connected to the output terminal of the filtering circuit, the input terminal of the filtering circuit is connected to the USB interface, the output terminal of the FT4232HL chip is connected to the ESD protection circuit, and the output terminal of the ESD protection circuit is connected to the 4 serial ports.
[0005] Furthermore, the VCCIO power pin of the FT4232HL chip is grounded through capacitors C8, C9, and C10, and is connected to a power supply voltage of 3.3V. The VCORE power pin of the FT4232HL chip is grounded through capacitors C5, C6, and C7, and is connected to a power supply voltage of 1.8V. The VCORE power pin is also connected to the VREGOUT pin of the FT4232HL chip. The VREGOUT pin of the FT4232HL chip is grounded through capacitor C14, and the VREGIN pin is grounded through capacitor C4. The grounding terminals of the FT4232HL chip are all common ground, and the common ground terminal is connected to the TEST test pin of the FT4232HL chip.
[0006] Furthermore, the FT4232HL chip is connected to an oscillation circuit to provide a stable clock signal for the microcontroller. The oscillation circuit includes capacitors C1 and C2 and a crystal oscillator Y1. The OSCI pin of the FT4232HL chip is connected to the OSCO pin of the FT4232HL chip through the crystal oscillator Y1. The two ends of the crystal oscillator Y1 are grounded through capacitors C1 and C2, respectively.
[0007] Furthermore, the FESET pin of the FT4232HL chip is connected to a power supply voltage of 3.3V through resistor R2, and the FEF pin of the FT4232HL chip is grounded through resistor R1.
[0008] Furthermore, the VPHY pin of the FT4232HL chip is connected to a power supply voltage of 3.3V through inductor L1, the VPLL pin of the FT4232HL chip is connected to a power supply voltage of 3.3V through inductor L2, the VPHY pin of the FT4232HL chip is grounded through capacitor C15, and the VPLL pin of the FT4232HL chip is grounded through capacitors C12 and C16 respectively.
[0009] Furthermore, the ESD protection circuit includes two TVS chips and two sets of thermistors. Each set of thermistors consists of two thermistors. Each TVS chip includes 4 input / output pins, and each set of thermistors includes 4 input / output pins.
[0010] The FT4232HL chip has four sets of transmit TXD / receive RXD ports. Every two sets of transmit TXD / receive RXD ports are connected to the four input pins of each thermistor. The four output pins of each thermistor are connected to the TX / RX pins of two serial ports.
[0011] One TVS chip has 4 input pins connected to 4 output pins of one set of thermistors, and its 4 output pins are connected to the TX / RX pins of 2 serial ports. The other TVS chip has 4 input pins connected to 4 output pins of another set of thermistors, and its 4 output pins are connected to the TX / RX pins of another 2 serial ports.
[0012] The TVS chip and the GND pin of the serial port are grounded.
[0013] Furthermore, the filtering circuit includes chip U2 and capacitor C3. Both output pins of chip U2 are connected to the VREGIN pin of the FT4232HL chip. Both output pins of chip U2 are connected to a power supply voltage of 3.3V. One output pin of chip U2 is connected to pin 4 of the USB interface. The output pin of chip U2 is grounded through capacitor C3, and the GND pin of chip U2 is grounded.
[0014] By adopting the above technical solution, this utility model has the following beneficial effects:
[0015] This utility model utilizes the FT4232HL chip to convert the USB protocol data output from the USB interface into a TTL serial port, realizing the USB to serial port function, providing a standardized output interface, and being compatible with the TTL level standard. Compared with the existing RS232 level, it has better compatibility with product levels.
[0016] This utility model's 4-serial-port converter adopts an anti-static design, providing more effective electrostatic protection and enabling it to cope with harsh testing environments.
[0017] This utility model's 4-serial-port converter is smaller than existing products of the same type, is compatible with PCIE and PCI slots, can be embedded in a computer motherboard, and is easy to integrate into a test computer. Attached Figure Description
[0018] Figure 1 This is a circuit diagram of a 4-serial-port converter for an automatic testing station according to the present invention.
[0019] In the diagram: 1-FT4232HL chip, 2-filter circuit, 3-USB interface, 4-ESD protection circuit, 5-4 serial port. Detailed Implementation
[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. The terms "first," "second," etc., in the specification, claims, and accompanying drawings of the present invention are used to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.
[0021] 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.
[0022] like Figure 1 As shown in the figure, an automatic test bench has a 4-serial port converter, including an FT4232HL chip 1, an ESD protection circuit, a filter circuit 2, a USB interface 3, and 4 serial ports 5. The data transmission port of the FT4232HL chip 1 is connected to the USB interface 3. The input voltage port of the FT4232HL chip 1 is connected to the output terminal of the filter circuit 2. The input terminal of the filter circuit 2 is connected to the USB interface 3. The output terminal of the FT4232HL chip 1 is connected to the ESD protection circuit. The output terminal of the ESD protection circuit is connected to the 4 serial ports 5. The 4 serial ports 5 are serial ports USART1, USART2, USART3, and USART4.
[0023] The VCCIO power pin of the FT4232HL chip 1 is grounded through capacitors C8, C9, and C10, and is connected to a power supply voltage of 3.3V. The VCORE power pin of the FT4232HL chip 1 is grounded through capacitors C5, C6, and C7, and is connected to a power supply voltage of 1.8V. The VCORE power pin is also connected to the VREGOUT pin of the FT4232HL chip 1. The VREGOUT pin of the FT4232HL chip 1 is grounded through capacitor C14, and the VREGIN pin of the FT4232HL chip 1 is grounded through capacitor C4. The grounding terminals of the FT4232HL chip 1 are all common to the ground, and the common ground terminal is connected to the TEST test pin of the FT4232HL chip 1.
[0024] The FT4232HL chip 1 is connected to an oscillation circuit to provide a stable clock signal for the microcontroller. The oscillation circuit includes capacitors C1 and C2 and a crystal oscillator Y1. The OSCI pin of the FT4232HL chip 1 is connected to the OSCO pin of the FT4232HL chip 1 through the crystal oscillator Y1. The two ends of the crystal oscillator Y1 are grounded through capacitors C1 and C2, respectively.
[0025] The FESET terminal of the FT4232HL chip 1 is connected to a power supply voltage of 3.3V through a resistor R2, and the FEF terminal of the FT4232HL chip 1 is grounded through a resistor R1.
[0026] The VPHY pin of the FT4232HL chip 1 is connected to a power supply voltage of 3.3V through inductor L1, and the VPLL pin of the FT4232HL chip 1 is connected to a power supply voltage of 3.3V through inductor L2. The VPHY pin of the FT4232HL chip 1 is grounded through capacitor C15, and the VPLL pin of the FT4232HL chip 1 is grounded through capacitors C12 and C16 respectively.
[0027] The ESD protection circuit includes two TVS chips and two sets of thermistors. Each set of thermistors consists of two thermistors: one set RT1 includes thermistors RT1A and RT1B, and the other set RT2 includes thermistors RT2A and RT2B. The two TVS chips are TVS chip D1 and TVS chip D2, respectively. Each TVS chip includes four input / output pins: IO-1, IO-2, IO-2, and IO-2. Each set of thermistors includes four input / output pins: pins 1, 2, 3, 4, 5, 6, 7, and 8.
[0028] The FT4232HL chip 1 has four sets of transmit TXD / receive RXD ports. Two sets of transmit TXD / receive RXD ports are connected to the four input pins 5, 6, 7, and 8 of the thermistor RT1, respectively. The four output pins 1, 2, 3, and 4 of the thermistor RT1 are connected to the TX / RX pins of serial ports USART1 and USART2, respectively. The other two sets of transmit TXD / receive RXD ports are connected to the four input pins 5, 6, 7, and 8 of the thermistor RT2, respectively. The four output pins 1, 2, 3, and 4 of the thermistor RT2 are connected to the TX / RX pins of serial ports USART3 and USART4, respectively.
[0029] The four input pins of TVS chip D1 are connected to the four output pins 1, 2, 3, and 4 of thermistor RT1, respectively. The four output pins of TVS chip D2 are also connected to the TX / RX pins of serial ports USART1 and USART2, respectively. The four input pins of TVS chip D2 are connected to the four output pins 1, 2, 3, and 4 of thermistor RT2, respectively. The four output pins of TVS chip D2 are also connected to the TX / RX pins of serial ports USART3 and USART4, respectively. The GND pin of both the TVS chip and the serial ports is grounded.
[0030] The filter circuit 2 includes a chip U2 and a capacitor C3. Both output pins of chip U2 are connected to the VREGIN pin of the FT4232HL chip 1. Both output pins of chip U2 are connected to a 3.3V power supply. One output pin of chip U2 is connected to pin 4 of the USB interface. The output pins of chip U2 are grounded through capacitor C3, and the GND pin of chip U2 is also grounded. The main function of filter circuit 2 is to filter out noise and interference from the signal.
[0031] This 4-port serial converter uses the FT4232HL chip to convert the USB protocol data output from the USB interface 3 into a TTL serial port, realizing the USB to serial port function. It is compatible with the TTL level standard and has good compatibility with product levels. It is suitable for a test bench with 4 interfaces for set-top boxes.
[0032] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the protection scope of the present invention.
Claims
1. A 4-serial-port converter for an automatic testing station, characterized in that, It includes an FT4232HL chip, an ESD protection circuit, a filtering circuit, a USB interface, and four serial ports. The data transmission port of the FT4232HL chip is connected to the USB interface, the input voltage port of the FT4232HL chip is connected to the output of the filtering circuit, the input of the filtering circuit is connected to the USB interface, the output of the FT4232HL chip is connected to the ESD protection circuit, and the output of the ESD protection circuit is connected to the four serial ports.
2. The 4-serial port converter for an automatic testing station according to claim 1, characterized in that, The VCCIO power pin of the FT4232HL chip is grounded through capacitors C8, C9, and C10, and is connected to a power supply voltage of 3.3V. The VCORE power pin of the FT4232HL chip is grounded through capacitors C5, C6, and C7, and is connected to a power supply voltage of 1.8V. The VCORE power pin is connected to the VREGOUT pin of the FT4232HL chip. The VREGOUT pin of the FT4232HL chip is grounded through capacitor C14, and the VREGIN pin of the FT4232HL chip is grounded through capacitor C4. The grounding terminals of the FT4232HL chip are common to each other, and the common ground terminal is connected to the TEST test pin of the FT4232HL chip.
3. The 4-serial port converter for an automatic testing station according to claim 1, characterized in that, The FT4232HL chip is connected to an oscillation circuit to provide a stable clock signal for the microcontroller. The oscillation circuit includes capacitors C1 and C2 and crystal Y1. The OSCI pin of the FT4232HL chip is connected to the OSCO pin of the FT4232HL chip through crystal Y1. The two ends of crystal Y1 are grounded through capacitors C1 and C2, respectively.
4. The 4-serial port converter for an automatic testing station according to claim 1, characterized in that, The FESET pin of the FT4232HL chip is connected to a power supply voltage of 3.3V through resistor R2, and the FEF pin of the FT4232HL chip is grounded through resistor R1.
5. A 4-serial port converter for an automatic testing station according to claim 1, characterized in that, The VPHY pin of the FT4232HL chip is connected to a power supply voltage of 3.3V through inductor L1, and the VPLL pins of the FT4232HL chip are connected to a power supply voltage of 3.3V through inductor L2. The VPHY pin of the FT4232HL chip is grounded through capacitor C15, and the VPLL pins of the FT4232HL chip are grounded through capacitors C12 and C16 respectively.
6. The 4-serial port converter for an automatic testing station according to claim 1, characterized in that, The ESD protection circuit includes two TVS chips and two sets of thermistors. Each set of thermistors consists of two thermistors. Each TVS chip includes 4 input / output pins, and each set of thermistors includes 4 input / output pins. The FT4232HL chip has four sets of transmit TXD / receive RXD ports. Every two sets of transmit TXD / receive RXD ports are connected to the four input pins of each thermistor. The four output pins of each thermistor are connected to the TX / RX pins of two serial ports. One TVS chip has 4 input pins connected to 4 output pins of one set of thermistors, and its 4 output pins are connected to the TX / RX pins of 2 serial ports. The other TVS chip has 4 input pins connected to 4 output pins of another set of thermistors, and its 4 output pins are connected to the TX / RX pins of another 2 serial ports. The TVS chip and the GND pin of the serial port are grounded.
7. A 4-serial port converter for an automatic testing station according to claim 1, characterized in that, The filtering circuit includes chip U2 and capacitor C3. Both output pins of chip U2 are connected to the VREGIN pin of the FT4232HL chip. Both output pins of chip U2 are connected to a power supply voltage of 3.3V. One output pin of chip U2 is connected to pin 4 of the USB interface. The output pin of chip U2 is grounded through capacitor C3, and the GND pin of chip U2 is grounded.