CN212137624U

CN212137624U - CAN communication filter circuit

Info

Publication number: CN212137624U
Application number: CN202021118702.7U
Authority: CN
Inventors: 许进
Original assignee: Hefei Guoxuan High Tech Power Energy Co Ltd
Current assignee: Hefei Gotion High Tech Power Energy Co Ltd
Priority date: 2020-06-16
Filing date: 2020-06-16
Publication date: 2020-12-11
Anticipated expiration: 2030-06-16

Abstract

The utility model discloses a CAN communication filter circuit in the CAN communication field, which comprises a CAN transceiver, wherein a CANH port of the CAN transceiver is connected with a first end of one coil of a common mode inductor, and a CANL port of the CAN transceiver is connected with a first end of the other coil of the common mode inductor; a first resistor and a second resistor which are connected in series are connected between a CANH port and a CANL port of the CAN transceiver, and the common end of the first resistor and the second resistor is grounded through a capacitor; and the second ends of the two coils of the common mode inductor are connected with voltage stabilizing diodes which are connected in series in an opposite direction. The utility model discloses filtering noise and most electromagnetic interference effectively, having improved communication quality, can satisfy pure electric vehicles's high-speed reliable communication demand.

Description

CAN communication filter circuit

Technical Field

The utility model relates to a CAN communication field specifically is a CAN communication filter circuit.

Background

The electric vehicle has a plurality of vehicle-mounted electric devices, and is different from the traditional internal combustion engine vehicle in that the electric vehicle belongs to strong-current application occasions, and the strong-current and weak-current coupling exists on the electric vehicle and the electromagnetic environment on the vehicle is complex due to the application.

The motor driving controller for the electric vehicle is an electrical device integrating a power supply, a control power supply and CAN bus communication. The CAN communication bus of the vehicle motor driving controller is used for receiving instructions from other vehicle-mounted equipment and transmitting the current state of the vehicle motor driving controller to the bus, when signals are interfered, the instructions CAN be analyzed wrongly, in the running process of the equipment, wrong instructions cause control errors, and especially when an electric vehicle runs at a high speed, the control errors seriously endanger the driving safety and cause personal injury; likewise, a spike in the power supply will cause unrecoverable damage to the power device, resulting in equipment damage.

In view of the above, the applicant proposes a CAN communication filter circuit.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a CAN communication filter circuit to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme:

a CAN communication filter circuit comprises a CAN transceiver, wherein a CANH port of the CAN transceiver is connected with a first end of one coil of a common-mode inductor, and a CANL port of the CAN transceiver is connected with a first end of the other coil of the common-mode inductor; a first resistor and a second resistor which are connected in series are connected between a CANH port and a CANL port of the CAN transceiver, and the common end of the first resistor and the second resistor is grounded through a capacitor; and the second ends of the two coils of the common mode inductor are connected with voltage stabilizing diodes which are connected in series in an opposite direction.

As the utility model discloses an improvement scheme, for filtering high frequency electromagnetic signal interference, protection CAN transceiver, still be connected with electric capacity C301 and electric capacity C332 of establishing ties mutually between CANH port and the CANL port of CAN transceiver, electric capacity C301 and electric capacity C332's common terminal ground connection.

As the improvement of the utility model, in order to filter the high frequency noise of the input end of supplying power, the power input end is connected to VDD1, VDD2 port of the CAN transceiver, VDD1 port is to ground parallel connection electric capacity C133 and C136, VDD2 port is to ground parallel connection zener diode D33 and electric capacity C109, C131.

As an improved scheme of the present invention, in order to facilitate decoupling voltage stabilization filtering, the CAN transceiver supplies power through a power module U22, the VIN + port of the power module U22 is connected to a 5V power supply through an inductor L14, and capacitors C350, C302 and C139 are connected in parallel to ground; a resistor R544 and capacitors C142 and C145 are connected in parallel between the + VO port and the 0V port of the power module U22, and the + VO port of the power module U22 is connected to the VDD2 port of the CAN transceiver.

As the utility model discloses a modified scheme, in order to Shield external disturbance, power module U22's 0V port is connected with output shielded wire Shield _ CAN through resistance R542 and electric capacity C340.

Has the advantages that: the utility model discloses filtering noise and most electromagnetic interference effectively, having improved communication quality, can satisfy pure electric vehicles's high-speed reliable communication demand.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1, a CAN communication filter circuit includes a CAN transceiver, which may be of TJA1052I type, a CANH port of the CAN transceiver is connected to a first end (4-pin) of one coil of a common mode inductor L13, and a CANL port is connected to a first end (3-pin) of the other coil of the common mode inductor L13; the common-mode inductor L13 can effectively filter out common-mode electromagnetic interference and reduce the capability of conducting interference to the outside.

A resistor R549 and a resistor R543 which are connected in series are connected between a CANH port and a CANL port of the CAN transceiver, and the common end of the resistor R549 and the resistor R543 is grounded (CAN _ CAN) through a capacitor C331. The resistor R549 and the resistor R543 are connected to form a 120 omega matching resistor, which can suppress the high-speed signal reflection echo,

the second ends (pin 1 and pin 2) of the two coils of the common mode inductor L13 are connected with a zener diode D70 which is connected in series in the reverse direction.

Specifically, there are two sets of reverse series zener diodes D70, each set including two zener diodes connected at their positive terminals. The cathode terminal (pin 1) of the first zener diode of the first group is connected to pin 1 of the common mode inductor L13, the cathode terminal (pin 2) of the second zener diode of the second group is connected to pin 2 of the common mode inductor L13, the cathode terminal of the second zener diode of the first group is connected to the cathode terminal of the first zener diode of the second group, and the common terminal (pin 3) thereof is grounded (CAN _ CAN).

The diode D70 has the function of suppressing the transient high voltage, which can improve the robustness of the circuit and prevent the chip from being destroyed by the external transient voltage to cause irreversible damage.

Specifically, the TXD port and the RXD port of the CAN transceiver are in direct communication with the electric vehicle main control chip through the resistor R124 and the resistor R133 respectively, and the resistors R124 and R133 play a role in current limiting protection.

Specifically, a capacitor C301 and a capacitor C332 connected in series are further connected between the CANH port and the CANL port of the CAN transceiver, and a common terminal of the capacitor C301 and the capacitor C332 is grounded. Capacitors C301 and C332 can both be 33pF, play the effect of filtering high frequency interference and preventing electromagnetic radiation, have also improved communication circuit's interference killing feature.

The power supply input end is connected with ports VDD1 and VDD2 of the CAN transceiver, a capacitor C133 and a capacitor C136 are connected in parallel with a VDD1 port to ground, a voltage stabilizing diode D33 and capacitors C109 and C131 are connected in parallel with a VDD2 port to ground, the capacitors C133 and C136 are used for filtering high-frequency noise of the 5V power supply input end, and the capacitors C109 and C131 play a role in filter protection.

Further, the CAN transceiver is powered by a power module U22, the power module U22 CAN be CF0505XT, the VIN + port of the power module U22 is connected to a 5V power supply through an inductor L14, and capacitors C350, C302 and C139 are connected in parallel to the ground, the inductor L14 CAN shield low-frequency noise introduced by a short power supply, and the capacitors C350, C302 and C139 CAN filter high-frequency noise input by a power supply terminal.

A resistor R544 and capacitors C142 and C145 are connected in parallel between the + VO port and the 0V port of the power module U22, and the power module U22 outputs a 5V isolation voltage as a power supply of the CAN transceiver. The capacitors C142 and C145 are preferably 10uF, the resistor R544 is preferably 470 Ω, and the capacitors C142 and C145 and the resistor R544 perform the function of decoupling the voltage stabilizing filter.

Further, the 0V port of the power module U22 is connected to the output shielded line Shield _ CAN through the resistor R542 and the capacitor C340, and plays a role in shielding external interference.

The utility model discloses filtering noise and most electromagnetic interference effectively, having improved communication quality, can satisfy pure electric vehicles's high-speed reliable communication demand.

Although the present description is described in terms of embodiments, not every embodiment includes only a single embodiment, and such description is for clarity only, and those skilled in the art should be able to integrate the description as a whole, and the embodiments can be appropriately combined to form other embodiments as will be understood by those skilled in the art.

In the description of the present invention, it is noted that relational terms such as first and second, and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

In the description of the present invention, it should be further noted that the terms "upper", "lower", "inner", "outer", and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the products of the present invention are used, and are only for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Therefore, the above description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application; all changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A CAN communication filter circuit is characterized by comprising a CAN transceiver, wherein a CANH port of the CAN transceiver is connected with a first end of one coil of a common mode inductor, and a CANL port of the CAN transceiver is connected with a first end of the other coil of the common mode inductor; a first resistor and a second resistor which are connected in series are connected between a CANH port and a CANL port of the CAN transceiver, and the common end of the first resistor and the second resistor is grounded through a capacitor; and the second ends of the two coils of the common mode inductor are connected with voltage stabilizing diodes which are connected in series in an opposite direction.

2. The CAN communication filter circuit according to claim 1, wherein a capacitor C301 and a capacitor C332 connected in series are further connected between the CANH port and the CANL port of the CAN transceiver, and a common terminal of the capacitor C301 and the capacitor C332 is grounded.

3. The CAN communication filter circuit of claim 1 or 2, wherein the ports VDD1 and VDD2 of the CAN transceiver are connected with the power supply input terminal, the port VDD1 is connected with the capacitors C133 and C136 in parallel to the ground, and the port VDD2 is connected with the voltage stabilizing diode D33 and the capacitors C109 and C131 in parallel to the ground.

4. The CAN communication filter circuit of claim 3, wherein the CAN transceiver is powered by a power module U22, the VIN + port of the power module U22 is connected to a 5V power supply through an inductor L14, and capacitors C350, C302 and C139 are connected in parallel to ground; a resistor R544 and capacitors C142 and C145 are connected in parallel between the + VO port and the 0V port of the power module U22, and the + VO port of the power module U22 is connected to the VDD2 port of the CAN transceiver.

5. The CAN communication filter circuit according to claim 4, wherein the 0V port of the power supply module U22 is connected to the output shielded line Shield _ CAN through a resistor R542 and a capacitor C340.