Discrete Type-C to USB interface circuit

Abstract

The utility model discloses a discrete Type-C to USB interface circuit, and relates to the technical field of USB communication. The circuit comprises an MOS tube, the D pole of the MOS tube outputs a USBDET signal, the G pole of the MOS tube is connected with a USBID signal through a first resistor and a first diode in sequence, the positive pole of the first diode is connected with the USBID signal, the positive pole of the first diode is further connected with a first power supply port through a second resistor, and the negative pole of the first diode is connected with a USBCC signal of a Type-C interface chip circuit; the S pole of the MOS tube is connected with the second power supply port, and the S pole is also connected with the G pole through a third resistor and a first capacitor; the second power supply port is grounded through the second capacitor; the voltage of the first power supply port is smaller than that of the second power supply port. According to the utility model, through the discrete Type-C to USB interface circuit, the USBDET level and the USBID level can be switched at the same time, and the problem that the mode cannot be switched or cannot be identified due to the fact that a master mode and a slave mode are switched only by identifying the USBID through software is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of USB communication, and particularly relates to a discrete Type-C to USB interface circuit. Background Art

[0002] With the development of USB technology, the USB Type-C interface has been widely used, replacing the previous microUSB interface. To complete the identification of master and slave devices for devices using the Type-C interface, it needs to be implemented by an external control chip, which has high cost and large space occupation of peripheral devices.

[0003] To simplify the circuit and cost, in the existing design, the USB_DET signal is default designed as high level, that is, it is default considered that there is always a USB device connected, and then the hot plug is completed through the state of USB_ID to switch the main and slave modes of the motherboard when different types of USB devices are connected. However, this solution has the situation of unable to switch the mode or not being recognized. Summary of the Invention

[0004] The technical problem to be solved by the utility model is to provide a discrete Type-C to USB interface circuit, which controls the power supply of USB_DET by controlling a MOS tube through the USB_ID signal, realizes the switching of the associated USB_DET state, and finally realizes the switching of the USB master and slave modes of the motherboard.

[0005] The utility model is realized as follows:

[0006] A discrete Type-C to USB interface circuit includes:

[0007] A MOS tube, the D pole of the MOS tube outputs the USB_DET signal, the G pole is sequentially connected to the USB_ID signal through a first resistor and a first diode, wherein the positive pole of the first diode is connected to the USB_ID signal, the positive pole of the first diode is also connected to the first power supply port through a second resistor, and the negative pole of the first diode is connected to the USB_CC signal of the Type-C interface chip circuit; the S pole of the MOS tube is connected to the second power supply port, and the S pole is also respectively connected to the G pole through a third resistor and a first capacitor; the second power supply port is grounded through a second capacitor; the voltage of the first power supply port is less than the voltage of the second power supply port;

[0008] When the USB_ID signal is low level and the USB_DET signal is high level, the motherboard switches to the HOST mode;

[0009] When the USB_ID signal is high level and the USB_DET signal is low level, the motherboard switches to the Device mode.

[0010] Further, the D pole of the MOS transistor is connected to the USB_DET signal terminal through a fourth resistor.

[0011] Further, the S pole of the MOS transistor is connected to the second power supply port through a second diode.

[0012] Further, the second diode is a germanium diode.

[0013] Further, the first diode is a germanium diode.

[0014] Further, the voltage of the first power supply port is 1.8V, and the voltage of the second power supply port is 5V.

[0015] Further, the MOS transistor is a PMOS transistor.

[0016] The advantages of the present utility model are as follows:

[0017] Through the designed discrete Type-C to USB interface circuit, the power supply of USB_DET is controlled by the method of controlling the MOS transistor according to the USB_ID signal, the switching of the state of USB_DET is realized, and finally the switching of the USB master-slave mode of the main board is realized. By realizing the simultaneous switching of the levels of USB_DET and USB_ID, the problems of unable to switch the mode or unrecognized caused by only relying on software to identify USB_ID to switch the master-slave mode are solved, the hardware cost and space are optimized, and at the same time, the time cost consumed by the switching and recognition problems during the development and use process is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following further describes the present utility model with reference to the accompanying drawings in conjunction with embodiments.

[0019] Figure 1 FIG. is a schematic structural diagram of a discrete Type-C to USB interface circuit according to an embodiment of the present utility model;

[0020] Figure 2 FIG. is a schematic structural diagram of a Type-C interface chip circuit according to an embodiment of the present utility model DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The technical solutions of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0022] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0023] Please refer to Figure 1 and Figure 2 As shown in, the embodiment of the present utility model provides a discrete Type-C to USB interface circuit, including:

[0024] A MOS transistor Q1 (a PMOS transistor can be used), the D pole of the MOS transistor Q1 outputs a USB_DET signal, the G pole is sequentially connected to the USB_ID signal through a first resistor R1 and a first diode D1. Among them, the positive pole of the first diode D1 is connected to the USB_ID signal, and the positive pole of the first diode D1 is also connected to a first power supply port VCC1 through a second resistor R2. The negative pole of the first diode D1 is connected to the USB_CC signal of the Type-C interface chip circuit; the S pole of the MOS transistor Q1 is connected to a second power supply port VCC2, and the S pole is also respectively connected to the G pole through a third resistor R3 and a first capacitor C1. The third resistor R3 and the first capacitor C1 are used to delay the signal rising edge at the moment when Q1 is turned on and reduce the overshoot, and the parameters can be self-matched; the second power supply port VCC2 is grounded through a second capacitor C2; the voltage of the first power supply port VCC1 is less than the voltage of the second power supply port VCC2; in this embodiment, the voltage of VCC1 is 1.8V, and the voltage of VCC2 is 5V.

[0025] When the USB_ID signal is at a low level and the USB_DET signal is at a high level, the main board switches to the HOST mode;

[0026] When the USB_ID signal is at a high level and the USB_DET signal is at a low level, the main board switches to the Device mode.

[0027] Preferably, the D pole of the MOS transistor is connected to the USB_DET signal terminal through a fourth resistor R4.

[0028] Preferably, the first diode D1 is preferably a germanium diode with a smaller tube voltage drop to prevent voltage backflow from affecting USB_ID.

[0029] Preferably, the S pole of the MOS transistor is connected to the second power supply port VCC2 through the second diode D2. The type selection of the second diode D2 is the same as that of the first diode D1. It is advisable to choose a germanium diode with a smaller forward voltage drop to prevent voltage backflow from affecting VCC2.

[0030] In this embodiment, the resistance value of the first resistor R1 is 10K, the resistance value of the second resistor R2 is 100K, and the resistance value of the third resistor R3 is 100K. The resistors and other components can adjust the circuit device parameters according to the actual situation, and add or reduce protection devices to match the applications under different conditions.

[0031] Figure 2 It is a Type-C interface chip circuit, including two CC pins (CC1, CC2). The USB_CC signal is obtained from these two pins. Among them, R5 and R6 are interface series resistors to absorb / reduce the static electricity energy generated during plugging and unplugging.

[0032] The working principle of the present utility model is as follows:

[0033] When Figure 2 the Type-C interface chip circuit is inserted into the TypeC OTG cable, and the other end of the cable is connected to a storage device such as a USB flash drive, since the CC pins inside the cable are pulled down to GND by 5.1KΩ, at this time the voltage level of the USB_ID pin becomes [5.1KΩ / (5.1KΩ + 100KΩ)]×1.8V≈0.087V (ignoring the forward voltage drop of D1), that is, a low level. At this time, the main board switches to the HOST mode. At the same time, the G pole of the MOS transistor Q1 is at a low level, the MOS transistor conducts, and USB_DET outputs a high level to supply power to the USB flash drive; at this time, USB_DET is high, and the main board considers that a device is inserted.

[0034] If the USB flash drive is unplugged and the Type-C interface is connected to the computer, the CC pins inside the cable are pulled up to VBUS, and at the same time the MOS transistor Q1 is turned off, and USB_DET has no output. At this time, the USB_ID pin of the main board is at a high level of 1.8V, and the main board switches to the Device mode.

[0035] During this process, not only the voltage level of the USB_ID pin is switched between high and low on the hardware, but also the voltage of USB_DET is controlled by switching.

[0036] By using a discrete Type-C to USB interface circuit to switch the levels of USB_DET and USB_ID simultaneously, it solves the problem of device unrecognition or misrecognition caused by relying solely on software to identify USB_ID to switch the master-slave mode.

[0037] The utility model controls the power supply of USB_DET by designing a discrete Type-C to USB interface circuit and controlling the MOS transistor according to the USB_ID signal, realizes the switching of the state associated with USB_DET, and finally realizes the switching of the main and slave modes of the motherboard USB. By simultaneously switching the levels of USB_DET and USB_ID, the problem of inability to switch modes or non-recognition caused by relying solely on software to identify USB_ID to switch the main and slave modes is solved, the hardware cost and space are optimized, and at the same time, the time cost consumed by the switching and recognition problems during the development and use process is avoided.

[0038] Although the specific implementation manners of the utility model have been described above, those skilled in the art of this technology should understand that the specific embodiments we described are illustrative rather than used to limit the scope of the utility model. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the utility model should be covered within the scope protected by the claims of the utility model.

Claims

1. A discrete Type-C to USB interface circuit, characterized in that: include: A MOS tube, wherein the D pole of the MOS tube outputs a USB_DET signal, and the G pole is connected to the USB_ID signal through a first resistor and a first diode in sequence, wherein the anode of the first diode is connected to the USB_ID signal, the anode of the first diode is also connected to the first power supply port through a second resistor, and the cathode of the first diode is connected to the USB_CC signal of the Type-C interface chip circuit; the S pole of the MOS tube is connected to the second power supply port, and the S pole is also connected to the G pole through a third resistor and a first capacitor respectively; the second power supply port is grounded through a second capacitor; the voltage of the first power supply port is less than the voltage of the second power supply port; When the USB_ID signal is low and the USB_DET signal is high, the motherboard switches to HOST mode; When the USB_ID signal is high and the USB_DET signal is low, the motherboard switches to Device mode.

2. The discrete Type-C to USB interface circuit according to claim 1, characterized in that: The D pole of the MOS tube is connected to the USB_DET signal terminal through a fourth resistor.

3. The discrete Type-C to USB interface circuit according to claim 1, characterized in that: The S pole of the MOS tube is connected to the second power supply port through a second diode.

4. The discrete Type-C to USB interface circuit according to claim 3, characterized in that: The second diode is a germanium diode.

5. The discrete Type-C to USB interface circuit according to claim 1 or 4, characterized in that: The first diode is a germanium diode.

6. The discrete Type-C to USB interface circuit according to claim 1, characterized in that: The voltage of the first power supply port is 1.8V, and the voltage of the second power supply port is 5V.

7. The discrete Type-C to USB interface circuit according to claim 1, characterized in that: The MOS tube is a PMOS tube.

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