CN204030947U - A kind of usb circuit - Google Patents
A kind of usb circuit Download PDFInfo
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- CN204030947U CN204030947U CN201420397222.7U CN201420397222U CN204030947U CN 204030947 U CN204030947 U CN 204030947U CN 201420397222 U CN201420397222 U CN 201420397222U CN 204030947 U CN204030947 U CN 204030947U
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Abstract
The utility model provides a kind of usb circuit, comprise USB joint, power supply common mode filtering module, signal common mode filtering module, power supply differential mode filtration module, signal differential mode filtration module and electrostatic protection module, power line in circuit can be eliminated, common mode disturbances on holding wire, the interference of difference film, electrostatic interference etc., the power supply common mode filtering module of especially setting up can eliminate the common mode disturbances problem between power supply VBUS and GND, shared by circuit, volume is little, cost is low, all fine to the protection effect of static discharge ESD and electromagnetic interference EMI, make usb signal no longer distortion, guarantee product smoothly by USB certification and EMC certification, practical.In addition the high voltage signal can also eliminated in circuit by high voltage protective module and High frequency filter module of the present utility model is disturbed and high-frequency signal interference, improves the antijamming capability of usb circuit further, improves its signal transmission performance.
Description
Technical Field
The utility model relates to a USB interface technical field especially relates to a USB interface circuit.
Background
The development of multimedia technology has led to the development of USB bus technology, which has increased the data transfer rate between the peripheral and the host. The Universal Serial Bus (USB) is a Universal Serial Bus (USB) which is researched and developed by companies such as Conpaq, DEC, IBM, Inter, Microsoft, NEC, Northen Telecom and the like for simplifying the interconnection between PC and peripheral equipment, and is free of charge, characterized by high speed, good compatibility, no interruption, capability of being connected in series, support of hot plug and the like, support of the connection between various PCs and peripheral equipment such as scanners, digital cameras, digital video cameras, audio systems, displays, input equipment and the like, and further realize digital multimedia integration.
The USB signal transmission cable is usually a twisted pair shielding ground, and comprises 3 pairs of USB signal lines and 1 pair of power lines inside, the input voltage value on the transmission channel is 4.07-5.25V, the maximum current transmitted is about 900mA, the transmission rate of the USB interface is very high, like USB2.0 with the maximum transmission rate of 480Mbit/s, the transmission rate of USB3.0 is more than 10 times of the transmission rate of USB 2.0. And the USB3.0 is gradually put into the market, which is a trend of future development. With the increase of the transmission rate, how to improve the transmission quality of the USB signal, and reducing the electromagnetic interference EMI and the electrostatic discharge ESD become the key of the design of the USB interface circuit.
Referring to fig. 1, in a USB interface circuit of the prior art, an inductor or a magnetic bead L1 is connected in series to a power line VBUS, and parallel capacitors C3 and C4 are also provided; meanwhile, a common mode choke L2 is connected in series on the USB data differential line pair D-, D +, thereby effectively reducing electromagnetic interference EMI. And ESD protection devices D1, D2 and D3 are arranged and connected in parallel between the USB data differential line pairs D-, D +, a power line, a working ground line and the ground or a metal shell (shielding layer) in the circuit respectively to perform electrostatic discharge ESD protection. The circuit can well reduce electromagnetic interference (EMI) and electrostatic discharge (ESD).
However, many intelligent electronic devices, such as wearable products and game pads, need to be powered by a host and communicate with the host through a USB interface, and this way requires that the electronic devices need to satisfy USB certification and EMC certification when working, and it is important whether the design of the USB interface circuit can make the USB certification and EMC certification succeed. However, in the circuit shown in fig. 1, on one hand, the ground line is not designed to be isolated, so that the working ground GND and the output ground are directly conducted, and as long as the external high voltage exists, the working ground GND and the output ground are directly connected into the internal circuit of the equipment, so that the machine is damaged, and when the PCB is wired, the insulation distance is not enough to meet the industrial requirements, and the withstand voltage cannot meet the requirements; on the other hand, the action time of the diodes D1, D2 and D3 is ps level, the action time of the inductor L1 is μ s level, and the diode D3 acts before the inductor L1 in a lightning stroke state, but because the diode D3 is too small in current resistance and easy to break down, the inductor L1 loses the protection effect, so that a common mode or differential mode filter protection circuit is lacked, and finally the ideal effect is difficult to achieve. Therefore, the current typical USB interface circuit causes the electronic device to have a great risk when passing USB authentication and EMC authentication, the USB signal is easily distorted, and the USB authentication and EMC authentication are easily failed.
Electromagnetic compatibility (EMC), among other things, refers to the ability of a device or system to perform satisfactorily in its electromagnetic environment without generating intolerable electromagnetic interference to any device in its environment. EMC generally includes two requirements: on one hand, the electromagnetic interference generated to the environment by the equipment in the normal operation process cannot exceed a certain limit value; another aspect is that the appliance has a degree of immunity to electromagnetic interference present in the environment, i.e., electromagnetic susceptibility. Therefore, EMC includes two parts, namely EMI (electromagnetic interference) and EMS (electromagnetic tolerance), so-called EMI electromagnetic interference is electromagnetic noise generated by the machine itself in the process of executing the proper function and is not beneficial to other systems; EMS electromagnetic tolerance refers to the ability of a machine to withstand the surrounding electromagnetic environment during the performance of its intended function.
Therefore, a new USB interface circuit is needed to avoid the above drawbacks.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a USB interface circuit can avoid the signal interference between power cord and the workplace for the USB signal is undistorted, ensures that the product passes through USB authentication and EMC authentication smoothly.
In order to solve the above problem, the utility model provides a USB interface circuit, include: the device comprises a USB joint, a power supply common-mode filtering module, a signal common-mode filtering module, a power supply differential-mode filtering module, a signal differential-mode filtering module and an electrostatic protection module; wherein,
the input end of the power supply common-mode filtering module is connected with a power supply terminal and a working ground terminal of the USB joint and is used for filtering common-mode interference signals on a power supply circuit and a working ground circuit;
the power supply differential mode filtering module is connected with the output end of the power supply common mode filtering module and is used for filtering differential mode interference signals on a power supply circuit;
the input end of the signal common-mode filtering module is connected with two terminals of a differential signal line of the USB joint and is used for filtering common-mode interference signals on a differential signal line;
the signal differential mode filtering module is connected with the output end of the signal common mode filtering module and is used for filtering differential mode interference signals on a differential signal line;
one end of the electrostatic protection module is connected with the shielding ground of the USB joint, and the other end of the electrostatic protection module is connected with the power circuit and the differential signal circuit and is used for eliminating electrostatic interference signals on the power circuit and the differential signal circuit.
Further, the power supply common mode filter module comprises a common mode inductor of which the input end is connected with the power supply terminal and the working ground terminal of the USB connector.
Furthermore, the power supply differential mode filtering module comprises at least one of a filtering inductor, a filtering capacitor, an LC filtering circuit and an RC filtering circuit.
Furthermore, the signal common mode filtering module comprises a common mode inductor of which the input end is connected with two terminals of the differential signal line of the USB connector.
Further, the signal differential mode filtering module includes at least one of a filter inductor, a filter capacitor, an LC filter circuit, and an RC filter circuit.
Further, the electrostatic protection module includes a discharge diode or an electrostatic protection chip.
Furthermore, the USB interface circuit further includes a high voltage protection module, one end of the high voltage protection module is connected to the shielding ground of the USB connector, and the other end is connected to the working ground line, the power line and the differential signal line, so as to eliminate high voltage interference signals on the working ground line, the power line and the differential signal line.
Furthermore, the high-voltage protection module comprises four piezoresistors, one ends of the four piezoresistors are all connected with a shielding ground of the USB connector, and the other ends of the four piezoresistors are respectively connected with the working ground circuit, the power supply circuit and the differential signal circuit.
Furthermore, the USB interface circuit further includes a high-frequency filtering module, and the high-frequency filtering module is disposed between the USB connector and the power common-mode filtering module and between the USB connector and the signal common-mode filtering module, and is configured to filter high-frequency signal interference on the power line and the differential signal line.
Furthermore, the high-frequency filtering module comprises two filtering inductors respectively connected in series between a power supply terminal, a working ground terminal and an input terminal of the power supply common-mode filtering module of the USB connector, and two filtering inductors respectively connected in series between two differential signal terminals of the USB connector and an input terminal of the signal common-mode filtering module.
Compared with the prior art, the utility model discloses a USB interface circuit, including the USB joint, power common mode filter module, signal common mode filter module, power differential mode filter module, signal differential mode filter module and electrostatic protection module, power cord in the cancelling circuit, common mode interference on the signal line, differential membrane interference, electrostatic interference etc. especially the power common mode filter module who adds can eliminate the common mode interference problem between power VBUS and the place of working GND for the USB signal is no longer distorted, ensures that the product passes through USB authentication and EMC authentication smoothly.
Drawings
FIG. 1 is a schematic diagram of a USB interface circuit in the prior art;
fig. 2 is a schematic diagram of a USB interface circuit system according to a first embodiment of the present invention;
fig. 3 is a schematic structural diagram of a USB interface circuit according to a first embodiment of the present invention;
fig. 4 is a schematic block diagram of a USB interface circuit system according to a second embodiment of the present invention;
fig. 5 is a schematic structural diagram of a USB interface circuit according to a second embodiment of the present invention;
fig. 6 is a schematic diagram of a USB interface circuit system module according to a third embodiment of the present invention;
fig. 7 is a schematic diagram of a specific structure of a USB interface circuit according to a third embodiment of the present invention.
Detailed Description
In order to make the objects and features of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Example one
Referring to fig. 2, the present embodiment provides a USB interface circuit, including: the device comprises a USB joint 1, a power supply common mode filtering module 2, a signal common mode filtering module 5, a power supply differential mode filtering module 3, a signal differential mode filtering module 6, an electrostatic protection module 4 and a grounding module 7; the input end of the power supply common mode filter module 2 is connected with a power supply terminal VBUS and a working ground terminal GND of the USB joint and is used for filtering common mode interference signals on a power supply line and a working ground line; the power supply differential mode filtering module 3 is connected with the output end of the power supply common mode filtering module 2 and is used for filtering differential mode interference signals on a power supply circuit; the input end of the signal common mode filtering module 5 is connected with two terminals D-D + of a differential signal line of the USB joint and is used for filtering common mode interference signals on the differential signal line; the signal differential mode filtering module 6 is connected with the output end of the signal common mode filtering module 5 and is used for filtering differential mode interference signals on a differential signal line; one end of the electrostatic protection module 4 is connected with the shielding ground of the USB joint 1, and the other end is connected with the power circuit and the differential signal circuit, and is used for eliminating electrostatic interference signals on the power circuit and the differential signal circuit. One end of the grounding module 7 is connected with the shielding ground of the USB connector, and the other end is connected with the ground or the earth of the circuit main board PCB of the electronic device, and the grounding module is used for grounding the shielding ground circuit of the USB connector and the ground single point of the circuit main board PCB of the electronic device.
Referring to fig. 3, when the USB interface has a power signal, the power signal needs to be filtered. The power supply common mode filtering module 2 and the power supply differential film filtering module 3 provided in the embodiment effectively isolate the working ground GND and the ground PGND of the PCB, and equivalently adjust the insulation distance of the PCB, so that the working ground GND and the ground PGND of the PCB are indirectly conducted, thereby suppressing the problem that high voltage existing outside the electronic equipment directly enters the inside of the PCB of the electronic equipment to damage the IC, and improving the voltage endurance capability of the electronic equipment; on the other hand, the transient diode D1 in the electrostatic protection module can be protected from breakdown, which plays a role of electrostatic protection, thereby reducing the risk of the electronic device when passing USB authentication and EMC authentication. The power supply common mode filter module 2 includes a common mode inductor L2, the power supply differential mode filter module 3 includes a filter inductor L1 and two parallel capacitors C1 and C2, wherein two input ends of L2 are connected to the power supply terminal VBUS and the working ground terminal GND of the USB connector, one end of the two output ends is grounded, the other end is connected in series to the filter inductor L1, the output end of L1 is led out to connect the USB interface circuit to the power supply interface VBUS of the electronic device PCB, one end of C1 and C2 is connected to the output end of L1, and the other end is grounded (which can be regarded as that the power supply VBUS is indirectly connected to GND). The L2 clamps the input common mode interference voltage, can filter the common mode interference signal on the power supply and the ground, and the LCC filter circuit composed of the L1, the C1 and the C2 clamps and releases the input differential mode interference voltage, and can be used for filtering the differential mode signal interference on the power supply. Wherein, L1 is 4.7 muH inductance (e.g. FBMA11160808601T), and C1 and C2 are small capacitances of 2.2 muF and 100nF, respectively. For the selection of the common mode inductor L2, the influence of the differential-mode parasitic inductance of the common mode inductor L2 (common mode choke) on the high-speed USB signal should be mainly considered, and if the parasitic differential-mode inductance is too large, the USB signal will be attenuated, and the operation performance of the USB interface will be affected, in this embodiment, the common mode inductor L2 is CM22012MCIN 121T.
Referring to fig. 3, in the present embodiment, the signal common mode filtering module 5 includes a common mode inductor L3, and the signal differential mode filtering module 6 includes two RC filtering circuits; the two input ends of the L2 are connected with a differential signal terminal D-and a differential signal terminal D + of the USB connector, the two output ends are respectively connected with a resistor R1 and a resistor R2 in series, the output end of the resistor R1 is led out to connect the USB interface circuit into the differential signal input end D-of the electronic equipment PCB, and the output end of the resistor R2 is led out to connect the USB interface circuit into the differential signal input end D + of the electronic equipment PCB; meanwhile, the output end of the resistor R1 is further connected to a grounded capacitor C4, the output end of the resistor R2 is further connected to another grounded capacitor C3, the R1 and the C4 form an RC filter circuit of the signal differential mode filter module 6, and the R2 and the C3 form another RC filter circuit of the signal differential mode filter module 6 (the two RC filter circuits can be regarded as connecting two differential signal terminals indirectly to GND). L3 can filter the common mode interference signal on the differential signal line, and two RC filter circuits can filter the differential mode interference signal on the differential signal line. In order to prevent USB signal distortion and successfully pass USB authentication, the resistors R1 and R2 are preferably piezoresistors with small capacitance values, such as small resistors of 22 ohms, and the parallel grounded capacitors C1 and C2 are preferably small capacitors, such as 2.2 μ F and 100 nF. For the selection of the common mode inductor L3, the influence of the differential-mode parasitic inductance of the common mode inductor L3 (common mode choke) on the high-speed USB signal should be mainly considered, and if the parasitic differential-mode inductance is too large, the USB signal is attenuated, and the operation performance of the USB interface is affected. In this embodiment, the common mode inductor L3 is CM22012MCIN 121T.
Because the USB interface has hot-pluggable property, the USB interface is easy to cause electrostatic damage to devices due to human factors, such as a dead halt, a reset, etc., and the PCB of the electronic device is more seriously burned out. Therefore, it is desirable to incorporate a protection device against ESD. In this embodiment, the electrostatic protection module 4 is used as an ESD protection device, mainly a device with very small parasitic capacitance, and may be disposed in a circuit after filtering differential mode interference signals, or disposed in a circuit before filtering common mode signal interference (please refer to fig. 6 and fig. 7), please refer to fig. 3 continuously, in this embodiment, the electrostatic protection module 4 is disposed in a circuit after filtering differential mode interference signals, and includes transient diodes (TVS transistors) D1, D2, and D3. One end of the D1 is connected with the output end of the L1, residual voltage clamped by the power supply differential film filtering module is discharged, and electrostatic interference on the power supply line is led into the shielding ground line, so that the electrostatic interference on the power supply line is eliminated; two ends of the D2 are respectively connected between a shielding ground SHLD wire (i.e. a connection line between the shielding ground SHLD and the ground of the PCB, which is a position of the electronic device housing in general) and the output end of the resistor R1, and two ends of the D3 are respectively connected between the shielding ground SHLD wire and the output end of the resistor R2, so as to discharge the residual voltage clamped by the signal differential filtering module for introducing the electrostatic interference on the differential signal wire into the shielding ground wire, thereby eliminating the electrostatic interference on the differential signal wire. Wherein D1, D2, D3 can be TVS-BV 05C.
Referring to fig. 3, in this embodiment, the grounding module 7 is a 0 ohm resistor R3, and the ground of the PCB and the shielding ground can be grounded at a single point by using the 0 ohm resistor, so as to prevent the shielding ground and the ground of the PCB from being coupled in series to generate a common ground impedance, and simultaneously insulate the ground of the differential signal line from the GND and the SHLD, so as to prevent the power frequency and other stray currents from interfering with the signal ground.
In the USB interface circuit of this embodiment, a power common mode filter module, a signal common mode filter module, a power differential mode filter module, a signal differential mode filter module, and an electrostatic protection module are disposed between a USB connector and a PCB of an electronic device; therefore, common mode interference, differential mode interference and electrostatic interference on the power circuit, the differential signal circuit and the working ground circuit can be eliminated, so that USB signals are not distorted any more, and the product is ensured to pass through USB authentication and EMC authentication smoothly.
Example two
Referring to fig. 4, the present embodiment provides a USB interface circuit, including: the device comprises a USB joint 1, a power supply common mode filtering module 2, a signal common mode filtering module 5, a power supply differential mode filtering module 3, a signal differential mode filtering module 6, an electrostatic protection module 4, a grounding module 7 and a high-voltage protection module 8.
The difference between this embodiment and the first embodiment is that a high voltage protection module 8 is added, one end of the high voltage protection module 8 is connected to a shielding ground of the USB connector, and the other end is connected to the working ground line, the power line and the differential signal line, and the high voltage protection module 8 may be disposed between the common mode filtering and the differential film filtering, or disposed before the common mode filtering or after the differential film filtering, preferably disposed before the differential film filtering, for eliminating high voltage interference signals on the working ground line, the power line and the differential signal line.
Referring to fig. 5, in the present embodiment, the high voltage protection module 8 includes four voltage dependent resistors V1, V2, V3, and V4. One end of each piezoresistor V1 is connected with a shielding ground wire, and the other end of each piezoresistor V1 is connected with a power supply circuit behind the common-mode inductor L2, so that high-voltage and high-energy on the power supply line can be conducted to the SHLD nearby, and the influence of high-voltage signal interference on the ground of the PCB on the normal work of the electronic equipment IC is avoided; one end of each piezoresistor V2 is connected with a shielding ground wire, and the other end of each piezoresistor V2 is connected with a working ground GND (ground) circuit behind the common-mode inductor L2, so that high voltage and high energy on the working ground wire are nearby conducted to the SHLD, and the situation that the normal work of the electronic equipment IC is influenced due to the fact that high voltage signals flow backwards or surge to the ground of the PCB is avoided; one end of each of the voltage dependent resistors V3 and V4 is connected with a shielding ground wire, and the other end of each of the voltage dependent resistors V3 and V4 is connected with a differential signal line behind the common-mode inductor L3 respectively, so that high voltage and high energy on the differential signal line are conducted to the SHLD nearby, and the situation that the high voltage signal flows backwards or surges to the ground of the PCB to influence the normal work of the IC of the electronic equipment is avoided.
Because differential mode interference existing in the circuit is generally spike pulse with large energy, the high-voltage protection module additionally arranged in the embodiment can absorb most of interference caused by static electricity and the like, high-voltage signal energy is firstly weakened onto the SHLD, and then residual energy is absorbed through the cooperation of the differential film filtering module and the static protection module, so that the high-voltage signal is prevented from flowing backwards or surging to the ground of the PCB from the working ground circuit, the power supply circuit and the differential signal circuit, and the normal work of the electronic equipment IC is ensured.
The USB interface circuit of this embodiment has the capability of suppressing high voltage interference compared to the USB interface circuit of the first embodiment because the high voltage protection module is provided.
EXAMPLE III
Referring to fig. 6, the present embodiment provides a USB interface circuit, including: the device comprises a USB joint 1, a power supply common mode filtering module 2, a signal common mode filtering module 5, a power supply differential mode filtering module 3, a signal differential mode filtering module 6, an electrostatic protection module 4, a grounding module 7, a high-voltage protection module 8 and a high-frequency filtering module 9.
The difference between this embodiment and the second embodiment is that a high-frequency filtering module 9 is additionally provided, and the high-frequency filtering module 9 is arranged between the USB connector 1 and the power supply common mode filtering module 2 and between the USB connector 9 and the signal common mode filtering module 5, and is used for filtering high-frequency signal interference on the power supply line and the differential signal line.
In this embodiment, the high-frequency filtering module 9 includes two filtering inductors (or magnetic beads) L4 and L5 respectively connected in series between the power supply terminal VBVU of the USB connector, the working ground GND and the input end of the common-mode inductor L2, and two filtering inductors (or magnetic beads) L6 and L7 respectively connected in series between the two differential signal terminals D-, D + of the USB connector and the input end of the common-mode inductor L3.
In this embodiment, the electrostatic protection module 4 is disposed between the USB connector and the high-frequency filtering module 9, and introduces a large amount of electrostatic charge to the SHLD, so as to prevent electrostatic high-voltage interference from entering the ground of the PCB and affecting the normal operation of the electronic device IC, and to prevent the interference of the high voltage caused by the electrostatic charge to the USB electrical signal.
Further, the working ground GND and the shielding ground SHLD of the USB cable may be connected through a bead of 100 Ω -600 Ω or a filter capacitor C5 or other filter circuits to eliminate interference with the working ground GND. In this embodiment, a filter capacitor C5 is provided to eliminate interference of the remaining various signals (especially the differential film signal) with the operating ground GND.
The USB interface circuit of this embodiment has the capability of suppressing the interference of high-frequency signals, compared with the USB interface circuit of the second embodiment, because the USB interface circuit of this embodiment is provided with the high-frequency filtering module.
It should be noted that, in the utility model, the power differential mode filter module is not only the LCC filter circuit listed in each above-mentioned embodiment, the signal differential mode filter module is not only the RC filter circuit listed in each above-mentioned embodiment, as long as the circuit that can realize differential mode filtering can all be replaced, therefore power differential mode filter module, signal differential mode filter module all can be by the filter circuit of electric capacity, resistance, inductance, the constitution of magnetic bead, for example pi type filter circuit, RCC (the filter circuit that a series resistance and two parallel capacitors constitute), CCL (the filter circuit that two parallel capacitors and a series inductance or magnetic bead constitute), CCR (the filter circuit that two parallel capacitors and a series resistance constitute), CC (the filter circuit that two parallel capacitors constitute), C (the filter circuit that an electric capacity and constitute) etc.. Similarly, the electrostatic protection module may also be an electrostatic protection chip, and is not limited to the examples in the first to third embodiments, which is not described herein again.
To sum up, the utility model discloses a USB interface circuit, including USB joint, power common mode filter module, signal common mode filter module, power differential mode filter module, signal differential mode filter module and electrostatic protection module, power cord in the cancelling circuit, common mode interference on the signal line, differential membrane interference, electrostatic interference etc. especially, the power common mode filter module who adds can eliminate the common mode interference problem between power VBUS and the place of work GND, the shared small, with low costs of circuit, the protecting effect to electrostatic discharge ESD and electromagnetic interference EMI is all fine, make the USB signal no longer distort, ensure that the product passes through USB authentication and EMC authentication smoothly, therefore, the clothes hanger is strong in practicability. Furthermore the utility model discloses a can also further improve USB interface circuit's interference killing feature through high-voltage signal interference and the high frequency signal interference among high-pressure protection module and the high frequency filter module elimination circuit, improve its signal transmission performance.
It will be apparent to those skilled in the art that various changes and modifications may be made to the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A USB interface circuit, comprising: the device comprises a USB joint, a power supply common-mode filtering module, a signal common-mode filtering module, a power supply differential-mode filtering module, a signal differential-mode filtering module and an electrostatic protection module; wherein,
the input end of the power supply common-mode filtering module is connected with a power supply terminal and a working ground terminal of the USB joint and is used for filtering common-mode interference signals on a power supply circuit and a working ground circuit;
the power supply differential mode filtering module is connected with the output end of the power supply common mode filtering module and is used for filtering differential mode interference signals on a power supply circuit;
the input end of the signal common-mode filtering module is connected with two terminals of a differential signal line of the USB joint and is used for filtering common-mode interference signals on a differential signal line;
the signal differential mode filtering module is connected with the output end of the signal common mode filtering module and is used for filtering differential mode interference signals on a differential signal line;
one end of the electrostatic protection module is connected with the shielding ground of the USB joint, and the other end of the electrostatic protection module is connected with the power circuit and the differential signal circuit and is used for eliminating electrostatic interference signals on the power circuit and the differential signal circuit.
2. The USB interface circuit of claim 1, wherein the power common mode filtering module includes a common mode inductor having an input connected to a power terminal and an operational ground terminal of the USB connector.
3. The USB interface circuit of claim 1, wherein the power differential mode filtering module comprises at least one of a filter inductance, a filter capacitance, an LC filter circuit, and an RC filter circuit.
4. The USB interface circuit of claim 1, wherein the signal common mode filtering module comprises a common mode inductor having an input connected to two terminals of the differential signal line of the USB connector.
5. The USB interface circuit of claim 1, wherein the signal differential mode filtering module comprises at least one of a filter inductance, a filter capacitance, an LC filter circuit, and an RC filter circuit.
6. The USB interface circuit of claim 1, wherein the esd protection module comprises a transient diode or an esd protection chip.
7. The USB interface circuit of claim 1, further comprising a high voltage protection module, wherein one end of the high voltage protection module is connected to the shielding ground of the USB connector, and one end of the high voltage protection module is connected to the working ground line, the power line and the differential signal line, so as to eliminate high voltage interference signals on the working ground line, the power line and the differential signal line.
8. The USB interface circuit of claim 7, wherein the high voltage protection module comprises four voltage dependent resistors, one end of each of the four voltage dependent resistors is connected to the shielding ground of the USB connector, and the other end of each of the four voltage dependent resistors is connected to the working ground line, the power line, and the differential signal line.
9. The USB interface circuit according to claim 1, further comprising a high frequency filter module disposed between the USB connector and the power common mode filter module and the signal common mode filter module for filtering high frequency signal interference on the power line and the differential signal line.
10. The USB interface circuit according to claim 9, wherein the high frequency filtering module comprises two filtering inductors or filtering beads respectively connected in series between the power supply terminal, the operating ground terminal and the input terminal of the power common mode filtering module of the USB connector, and two filtering inductors or filtering beads respectively connected in series between the differential signal terminals of the USB connector and the input terminal of the signal common mode filtering module.
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| CN201420397222.7U CN204030947U (en) | 2014-07-17 | 2014-07-17 | A kind of usb circuit |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104135148A (en) * | 2014-07-17 | 2014-11-05 | 青岛歌尔声学科技有限公司 | USB (Universal Serial Bus) interface circuit |
| CN105790026A (en) * | 2016-02-25 | 2016-07-20 | 广东欧珀移动通信有限公司 | Mobile terminal, universal serial bus interface and manufacturing method therefor |
| CN105826894A (en) * | 2015-06-25 | 2016-08-03 | 维沃移动通信有限公司 | Charging short-circuit protection device of power supply equipment and power supply equipment |
| CN106897241A (en) * | 2016-12-28 | 2017-06-27 | 深圳天珑无线科技有限公司 | A kind of usb circuit and mobile terminal being applied in mobile terminal |
| CN108021522A (en) * | 2017-12-14 | 2018-05-11 | 威创集团股份有限公司 | USB device master slave mode switching circuit |
| CN108111012A (en) * | 2017-12-14 | 2018-06-01 | 北京卫星制造厂 | A kind of high-power power supply and high-voltage motor drive module match circuit |
| CN110690691A (en) * | 2018-07-05 | 2020-01-14 | 维谛技术有限公司 | A device interface protection circuit |
| CN111371468A (en) * | 2020-03-24 | 2020-07-03 | 上海格巍半导体有限公司 | Signal transmitting circuit, signal receiving circuit and electronic equipment for serial communication |
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2014
- 2014-07-17 CN CN201420397222.7U patent/CN204030947U/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104135148A (en) * | 2014-07-17 | 2014-11-05 | 青岛歌尔声学科技有限公司 | USB (Universal Serial Bus) interface circuit |
| CN104135148B (en) * | 2014-07-17 | 2018-01-12 | 青岛歌尔声学科技有限公司 | A kind of usb circuit |
| CN105826894A (en) * | 2015-06-25 | 2016-08-03 | 维沃移动通信有限公司 | Charging short-circuit protection device of power supply equipment and power supply equipment |
| CN105826894B (en) * | 2015-06-25 | 2018-06-26 | 维沃移动通信有限公司 | The charging short-circuit protection and power-supply device of power-supply device |
| CN105790026A (en) * | 2016-02-25 | 2016-07-20 | 广东欧珀移动通信有限公司 | Mobile terminal, universal serial bus interface and manufacturing method therefor |
| CN105790026B (en) * | 2016-02-25 | 2018-01-23 | 广东欧珀移动通信有限公司 | Mobile terminal, USB and its manufacture method |
| CN106897241A (en) * | 2016-12-28 | 2017-06-27 | 深圳天珑无线科技有限公司 | A kind of usb circuit and mobile terminal being applied in mobile terminal |
| CN108021522A (en) * | 2017-12-14 | 2018-05-11 | 威创集团股份有限公司 | USB device master slave mode switching circuit |
| CN108111012A (en) * | 2017-12-14 | 2018-06-01 | 北京卫星制造厂 | A kind of high-power power supply and high-voltage motor drive module match circuit |
| CN110690691A (en) * | 2018-07-05 | 2020-01-14 | 维谛技术有限公司 | A device interface protection circuit |
| CN111371468A (en) * | 2020-03-24 | 2020-07-03 | 上海格巍半导体有限公司 | Signal transmitting circuit, signal receiving circuit and electronic equipment for serial communication |
| CN111371468B (en) * | 2020-03-24 | 2021-07-23 | 上海格巍半导体有限公司 | Signal transmitting circuit, signal receiving circuit and electronic equipment for serial communication |
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