Patent ID: 12212708

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. In the drawings, the shape and thickness may be exaggerated for clarity and convenience. This description will be directed in particular to elements forming part of, or cooperating more directly with, methods and apparatus in accordance with the present disclosure. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art. Many alternatives and modifications will be apparent to those skilled in the art, once informed by the present disclosure.

The embodiments described below are illustrated to demonstrate the technical contents and characteristics of the present invention and to enable the persons skilled in the art to understand, make, and use the present invention. However, it shall be noticed that it is not intended to limit the scope of the present invention. Therefore, any equivalent modification or variation according to the spirit of the present invention is to be also included within the scope of the present invention.

Unless otherwise specified, some conditional sentences or words, such as “can”, “could”, “might”, or “may”, usually attempt to express that the embodiment in the invention has, but it can also be interpreted as a feature, element, or step that may not be needed. In other embodiments, these features, elements, or steps may not be required.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.

Certain terms are used throughout the description and the claims to refer to particular components. One skilled in the art appreciates that a component may be referred to as different names. This disclosure does not intend to distinguish between components that differ in name but not in function. In the description and in the claims, the term “comprise” is used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to.” The phrases “be coupled to,” “couples to,” and “coupling to” are intended to compass any indirect or direct connection. Accordingly, if this disclosure mentioned that a first device is coupled with a second device, it means that the first device may be directly or indirectly connected to the second device through electrical connections, wireless communications, optical communications, or other signal connections with/without other intermediate devices or connection means.

The invention is particularly described with the following examples which are only for instance. Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the following disclosure should be construed as limited only by the metes and bounds of the appended claims. In the whole patent application and the claims, except for clearly described content, the meaning of the article “a” and “the” includes the meaning of “one or at least one” of the element or component. Moreover, in the whole patent application and the claims, except that the plurality can be excluded obviously according to the context, the singular articles also contain the description for the plurality of elements or components. In the entire specification and claims, unless the contents clearly specify the meaning of some terms, the meaning of the article “wherein” includes the meaning of the articles “wherein” and “whereon”. The meanings of every term used in the present claims and specification refer to a usual meaning known to one skilled in the art unless the meaning is additionally annotated. Some terms used to describe the invention will be discussed to guide practitioners about the invention. Every example in the present specification cannot limit the claimed scope of the invention.

The terms “substantially,” “around,” “about” and “approximately” can refer to within 20% of a given value or range, and preferably within 10%. Besides, the quantities provided herein can be approximate ones and can be described with the aforementioned terms if are without being specified. When a quantity, density, or other parameters includes a specified range, preferable range or listed ideal values, their values can be viewed as any number within the given range.

As the Applicants have described earlier in the Description of the Prior Art, since a ringing phenomenon is generally generated by the reflections of communication voltage wave, which occur because of impedance mismatches in a controller area network at the signal transition frequencies, and the impedance mismatches occur mainly at not-terminated nodes and the junction, the present invention is provided and aimed to solve such ringing phenomenon by proposing a novel and inventive ringing suppression circuit. The disclosed ringing suppression circuit is applicable to a transmitter (TX) module in a controller area network (CAN).

Please referFIG.2which schematically shows an illustrative diagram of a ringing suppression circuit in accordance with one embodiment of the present invention. As shown inFIG.2, the ringing suppression circuit20includes a CANH driver circuit102, a first operable circuit210, a second operable circuit220, a CANL driver circuit104and a termination component106.

According to the embodiment of the present invention, the CANH driver circuit102includes a first transistor TX1-P, a second transistor TX2-P and a third transistor TX3-N. The first transistor TX1-P is electrically connected with a supplied voltage Vcc, the second transistor TX2-P, the third transistor TX3-N and the first operable circuit210. The second transistor TX2-P is electrically connected with the supplied voltage Vcc, the first transistor TX1-P, the third transistor TX3-N and the first operable circuit210. And the third transistor TX3-N is electrically connected with the first transistor TX1-P, the second transistor TX2-P, the first operable circuit210and a ground GND. A first joint node N1is configured between the first transistor TX1-P, the second transistor TX2-P, the third transistor TX3-N and the first operable circuit210. According to the embodiment, the first transistor TX1-P and the second transistor TX2-P of the CANH driver circuit102is illustrated as a P-type MOSFET. The third transistor TX3-N of the CANH driver circuit102is illustrated as an N-type MOSFET. According to such embodiment, the Applicants merely depicts the CANH driver circuit102as being composed of one first transistor TX1-P, one second transistor TX2-P and one third transistor TX3-N for describing the technical contents of the present invention. However, the numbers of the first transistor TX1-P, the second transistor TX2-P and the third transistor TX3-N in which the CANH driver circuit102includes, may be more than one. In an alternative embodiment of the present invention, the CANH driver circuit102may also include a plurality of first transistor TX1-P. Alternatively, the CANH driver circuit102may also include a plurality of second transistor TX2-P. And similarly, the CANH driver circuit102in yet another embodiment of the present invention, may also further include a plurality of third transistor TX3-N. The applicants will provide further descriptions and discuss later in the following paragraphs. Hereinafter, a relatively low-complexity embodiment as shown inFIG.2is disclosed first for merely explaining the technical contents of the present invention. The present invention is not limited thereto such embodiment.

In view of the similar design manners, the CANL driver circuit104includes a fourth transistor TX4-N, a fifth transistor TX5-N and a sixth transistor TX6-P. The fourth transistor TX4-N is electrically connected with the fifth transistor TX5-N, the sixth transistor TX6-P, the second operable circuit220and the ground GND.

The fifth transistor TX5-N is electrically connected with the fourth transistor TX4-N, the sixth transistor TX6-P, the second operable circuit220and the ground GND. And the sixth transistor TX6-P is electrically connected with the fourth transistor TX4-N, the fifth transistor TX5-N, the second operable circuit220and the supplied voltage Vcc. A second joint node N2is configured between the fourth transistor TX4-N, the fifth transistor TX5-N, the sixth transistor TX6-P and the second operable circuit220.

According to such an embodiment, the fourth transistor TX4-N and the fifth transistor TX5-N of the CANL driver circuit104is illustrated as an N-type MOSFET. On the other hand, the sixth transistor TX6-P of the CANL driver circuit104is illustrated as a P-type MOSFET. According to such embodiment, the Applicants merely depicts the CANL driver circuit104as being composed of one fourth transistor TX4-N, one fifth transistor TX5-N and one sixth transistor TX6-P for introducing the technical contents of the present invention. However, the numbers of the fourth transistor TX4-N, the fifth transistor TX5-N and the sixth transistor TX6-P for fabricating the CANL driver circuit104may be more than one. For people who have ordinary knowledge and are skilled in the art, it is obvious that the numbers of the first transistor TX1-P, the second transistor TX2-P and the third transistor TX3-N of the CANH driver circuit102as well as the numbers of the fourth transistor TX4-N, the fifth transistor TX5-N and the sixth transistor TX6-P of the CANL driver circuit104can be adjusted and modified according to various practical requirements. And these variations still fall into the claim scope of the present invention with equality.

In other words, according to an alternative embodiment of the present invention, the CANL driver circuit104may include a plurality of fourth transistor TX4-N. Alternatively, the CANL driver circuit104may also include a plurality of fifth transistor TX5-N. And similarly, the CANL driver circuit104in yet another embodiment of the present invention, may also further include a plurality of sixth transistor TX6-P. The applicants will provide further descriptions and discuss later in the following paragraphs. Hereinafter, a relatively low-complexity embodiment as shown inFIG.2is disclosed first for merely explaining the technical contents of the present invention. The present invention is not limited thereto such embodiment.

According to the embodiment of the present invention, the first operable circuit210is electrically connected with the supplied voltage Vcc, the ground GND, the CANH driver circuit102and a first end of the termination component106, and the first operable circuit210generates a CAN high signal CANH at the first end of the termination component106. In view of the embodiment of the present invention, the first operable circuit210includes a first control element HV_MN1and a second control element HV_MP2which are electrically connected in cascade. The first control element HV_MN1is electrically connected between the supplied voltage Vcc, the CANH driver circuit102and the second control element HV_MP2, and the second control element HV_MP2is electrically connected between the first control element HV_MN1, the ground GND and the first end of the termination component106. According to the embodiment, the first control element HV_MN1is implemented by a high-voltage N-type MOSFET. Similarly, the second control element HV_MP2in such embodiment as shown inFIG.2is implemented by using a high-voltage P-type MOSFET. The first parasitic diode D1performs as a parasitic body diode of the first control element HV_MN1, while the second parasitic diode D2performs as a parasitic body diode of the second control element HV_MP2. In general, the first control element HV_MN1and the second control element HV_MP2mainly act as diodes so as to prevent any unwanted current flowing from CANH to the node of the supplied voltage Vcc and the ground GND. Without the first control element HV_MN1, when a voltage level of the CAN high signal CANH at the first end of the termination component106is higher than the supplied voltage Vcc, it will induce unwanted current from CANH to Vcc through the parasitic body diodes of the first transistor TX1-P and the second transistor TX2-P. On the other hand, without the second control element HV_MP2, when a voltage level of the CAN high signal CANH at the first end of the termination component106is lower than a voltage level of the ground GND, it will induce unwanted current from CANH to the ground GND through the parasitic body diode of the third transistor TX3-N. Furthermore, when the proposed ringing suppression circuit is applicable to a transmitter (TX) module, the first control element HV_MN1and the second control element HV_MP2may also perform to block the several dozens of common mode voltages from the CAN bus which will damage the device of the transmitter (TX) module.

In another aspect, when considering the second operable circuit220, the second operable circuit220is electrically connected with the supplied voltage Vcc, the ground GND, the CANL driver circuit104and a second end of the termination component106, and the second operable circuit220is aimed to generate a CAN low signal CANL at the second end of the termination component106. According to the embodiment of the present invention, it can be seen that the second operable circuit220includes a third control element HV_MP3and a fourth control element HV_MN4which are electrically connected in cascade.

The third control element HV_MP3is electrically connected between the ground GND, the second end of the termination component106and the fourth control element HV_MN4, and the fourth control element HV_MN4is electrically connected between the third control element HV_MP3, the supplied voltage Vcc and the CANL driver circuit104. According to the embodiment, the third control element HV_MP3is implemented by a high-voltage P-type MOSFET. Similarly, the fourth control element HV_MN4in such embodiment as shown inFIG.2is implemented by using a high-voltage N-type MOSFET. The third parasitic diode D3performs as a parasitic body diode of the third control element HV_MP3, while the fourth parasitic diode D4performs as a parasitic body diode of the fourth control element HV_MN4. In general, the third control element HV_MP3and the fourth control element HV_MN4mainly act as diodes so as to prevent any unwanted current flowing from CANL to the node of the supplied voltage Vcc and the ground GND. Without the third control element HV_MP3, when a voltage level of the CAN low signal CANL at the second end of the termination component106is lower than a voltage level of the ground GND, it will induce unwanted current from CANL to the ground GND through the parasitic body diodes of the fourth transistor TX4-N and the fifth transistor TX5-N. On the other hand, without the fourth control element HV_MN4, when a voltage level of the CAN low signal CANL at the second end of the termination component106is higher than the supplied voltage Vcc, it will induce unwanted current from CANH to Vcc through the parasitic body diode of the sixth transistor TX6-P. According to the similar manners, when the proposed ringing suppression circuit is applicable to a transmitter (TX) module in an alternative variant embodiment of the present invention, then the third control element HV_MP3and the fourth control element HV_MN4may also perform to block the several dozens of common mode voltages from the CAN bus which will damage the device of the transmitter (TX) module.

Furthermore, the termination component106is electrically connected between the first operable circuit210and the second operable circuit220. More specifically, the termination component106is electrically connected between the second control element HV_MP2of the first operable circuit210and the third control element HV_MP3of the second operable circuit220, such that at the first end of the termination component106is the CAN high signal CANH to be output and being electrically connected with. And at the second end of the termination component106is the CAN low signal CANL to be output and being electrically connected with. According to the embodiment of the present invention, the termination component106is typically used as a resistor having 600 resistance.

Nevertheless, it draws our attention that, the present invention is not limited thereto by the foregoing schematic diagram, and yet some alternative variations and embodiments will be provided and discussed by the applicants of the present invention later in the following paragraphs of the invention application.

Subsequently, please refer toFIG.3, in whichFIG.3schematically shows an illustrative diagram when the proposed ringing suppression circuit is applicable to a transmitter module in a controller area network in accordance with the embodiment of the present invention. Please refer toFIG.2andFIG.3at the same time, the ringing suppression circuit20as previously described is now applied to a transmitter module302in a controller area network. As can be seen inFIG.3, the transmitter module302further comprises a control signal generator300, and the control signal generator300receives a transmit (TX) data signal TXD. As a result, upon receiving the transmit (TX) data signal TXD, the control signal generator300correspondingly generates at least one first control signal G1, at least one second control signal G2and at least one third control signal G3which are in response to the transmit (TX) data signal TXD. According to the embodiment of the present invention, the first control signal G1is transmitted to the first transistor TX1-P of the CANH driver circuit102for turning on the first transistor TX1-P. The second control signal G2is transmitted to the second transistor TX2-P of the CANH driver circuit102for turning on the second transistor TX2-P, and the third control signal G3is transmitted to the third transistor TX3-N of the CANH driver circuit102for turning on the third transistor TX3-N.

As previously described, according to the alternative embodiment of the present invention when the CANH driver circuit102includes a plurality of first transistor TX1-P, a plurality of second transistor TX2-P or a plurality of third transistor TX3-N, then a plurality of first control signal G1will be generated to be transmitted to the plurality of first transistor TX1-P for turning on the plurality of first transistor TX1-P. A plurality of second control signal G2will be generated to be transmitted to the plurality of second transistor TX2-P for turning on the plurality of second transistor TX2-P. A plurality of third control signal G3will be generated to be transmitted to the plurality of third transistor TX3-N for turning on the plurality of third transistor TX3-N. Each of the first control signals G1, the second control signals G2and the third control signals G3is used to control and turn on one of the first transistor TX1-P, the second transistor TX2-P and the third transistor TX3-N, respectively.

Subsequently, please refer toFIG.4for a plurality of signal waveforms, depicting the transmit (TX) data signal TXD, the first control signal G1, the second control signal G2, the third control signal G3, the CAN high signal CANH, the CAN low signal CANL and the CAN bus differential voltage Vod, in view of the CANH driver circuit when the proposed ringing suppression circuit is applied to the transmitter module in the controller area network in accordance with the embodiment as shown inFIG.3of the present invention. As can be seen inFIG.4, the first control signal G1which is used to control and turn on the first transistor TX1-P is identical to the transmit (TX) data signal TXD. The first control signal G1is then transmitted to a gate terminal of the first transistor TX1-P. The second control signal G2which is used to control and turn on the second transistor TX2-P as well as the third control signal G3which is used to control and turn on the third transistor TX3-N are related and in response to the transmit (TX) data signal TXD. The second control signal G2is transmitted to a gate terminal of the second transistor TX2-P. And the third control signal G3is transmitted to a gate terminal of the third transistor TX3-N. As illustrated from the first, second and third control signal waveforms of G1, G2and G3inFIG.4, it is apparent that the first transistor TX1-P, the second transistor TX2-P and the third transistor TX3-N of the CANH driver circuit102are sequentially turned on.

The CAN high signal CANH and the CAN low signal CANL are generated respectively at the first end of the termination component106and at the second end of the termination component106. The CAN bus differential voltage Vod is a differential voltage signal between the CAN high signal CANH and the CAN low signal CANL, indicating that (Vod=CANH−CANL). As illustrated in the waveforms inFIG.4, the CAN high signal CANH is depicted by a solid line, while the CAN low signal CANL is depicted by a dashed line.

As we can see, at t−t1, the transmit (TX) data signal TXD sends a dominate signal to the transmitter module, and the first control signal G1and the second control signal G2respectively turns on the first transistor TX1-P and the second transistor TX2-P. As a result, it starts to drive the CAN bus differential voltage Vod (CANH−CANL) to a high voltage level, for instance, 2V. At this point of time, the CAN bus differential voltage Vod enters in a dominate state, labeled as “D” inFIG.4.

Then, at t=t2, the transmit (TX) data signal TXD sends a recessive signal to the transmitter module, and the first control signal G1starts to turn off the first transistor TX1-P while the second transistor TX2-P is stilled turned on. At the same time, the third control signal G3starts to turn on the third transistor TX3-N. As a result, the third transistor TX3-N performs to start pumping out the current of the second transistor TX2-P and the CAN bus enters in a recessive state, labeled as “R” inFIG.4.

Later, during t2<t<t3 (illustrated as “Tactrec” inFIG.4), that is called an active recessive state. In such a period of time during Tactrec, it is believed that the current of the second transistor TX2-P fully flows to the third transistor TX3-N, such that there is no current flowing to the CAN bus. As a result, it is obvious that due to the above-disclosed mechanism, the CAN bus differential voltage Vod is reduced to zero. And after that, the second transistor TX2-P and the third transistor TX3-N will be turned off respectively by the second control signal G2and the third control signal G3slowly after t=t3.

To be more specific, since the voltage of the first joint node N1is biased by the second transistor TX2-P and the third transistor TX3-N actively and the input resistance (Ri) of the CAN bus is also decided by the second transistor TX2-P and the third transistor TX3-N and believed to be controlled in a low impedance state when the CAN bus transits from the dominant state “D” to the recessive state “R” and also in the active recessive state, as a result, it is evident that by employing the proposed scheme of the present invention, the disclosed circuit diagram effectively achieves in suppressing the conventional ringing phenomenon.

Furthermore, since a glitch of the CAN high signal CANH and the CAN low signal CANL may affect electromagnetic emission directly, in order to reduce the glitch of (CANH+CANL), the first transistor TX1-P, the second transistor TX2-P and the third transistor TX3-N of the CANH driver circuit102can be made of one or more transistors. By sequentially turning on the at least one first transistor TX1-P, the at least one second transistor TX2-P and the at least one third transistor TX3-N, it is believed that the present invention further achieves in reducing the glitch of (CANH+CANL) and a superior electromagnetic emission (EME) performance can thus be maintained.

And yet, from another point of view, as can be seen in view ofFIG.3, the control signal generator300receives the transmit (TX) data signal TXD. And, upon receiving the transmit (TX) data signal TXD, the control signal generator300in addition, correspondingly generates at least one fourth control signal G4, at least one fifth control signal G5and at least one sixth control signal G6which are in response to the transmit (TX) data signal TXD. According to the embodiment of the present invention, the fourth control signal G4is transmitted to the fourth transistor TX4-N of the CANL driver circuit104for turning on the fourth transistor TX4-N. The fifth control signal G5is transmitted to the fifth transistor TX5-N of the CANL driver circuit104for turning on the fifth transistor TX5-N and the sixth control signal G6is transmitted to the sixth transistor TX6-P of the CANL driver circuit104for turning on the sixth transistor TX6-P.

As previously described, according to the alternative embodiment of the present invention when the CANL driver circuit104further includes a plurality of fourth transistor TX4-N, a plurality of fifth transistor TX5-N or a plurality of sixth transistor TX6-P, under such a circumstance, a plurality of fourth control signal G4will then be generated to be transmitted to the plurality of fourth transistor TX4-N for turning on the plurality of fourth transistor TX4-N. Similarly, a plurality of fifth control signal G5will be generated to be transmitted to the plurality of fifth transistor TX5-N for turning on the plurality of fifth transistor TX5-N. And, a plurality of sixth control signal G6will be generated to be transmitted to the plurality of sixth transistor TX6-P for turning on the plurality of sixth transistor TX6-P. Each of the fourth control signals G4, the fifth control signals G5and the sixth control signals G6is used to control and turn on one of the fourth transistor TX4-N, the fifth transistor TX5-N and the sixth transistor TX6-P, respectively.

And furthermore, please refer toFIG.5for a plurality of signal waveforms, depicting the transmit (TX) data signal TXD, the fourth control signal G4, the fifth control signal G5, the sixth control signal G6, the CAN high signal CANH, the CAN low signal CANL and the CAN bus differential voltage Vod, in view of the CANL driver circuit when the proposed ringing suppression circuit is applied to the transmitter module in the controller area network in accordance with the embodiment as shown inFIG.3of the present invention. As can be seen inFIG.5, the fourth control signal G4which is used to control and turn on the fourth transistor TX4-N is related and in response to the transmit (TX) data signal TXD. The fourth control signal G4is transmitted to a gate terminal of the fourth transistor TX4-N. The fifth control signal G5which is used to control and turn on the fifth transistor TX5-N is related and in response to the transmit (TX) data signal TXD. The fifth control signal G5is transmitted to a gate terminal of the fifth transistor TX5-N. The sixth control signal G6which is used to control and turn on the sixth transistor TX6-P is related and in response to the transmit (TX) data signal TXD. The sixth control signal G6is transmitted to a gate terminal of the sixth transistor TX6-P. As illustrated from the fourth, the fifth and the sixth control signal waveforms of G4, G5and G6inFIG.5, it is apparent that the fourth transistor TX4-N, the fifth transistor TX5-N and the sixth transistor TX6-P of the CANL driver circuit104are sequentially turned on.

Since the CAN high signal CANH and the CAN low signal CANL are generated respectively at the first end of the termination component106and at the second end of the termination component106, the CAN bus differential voltage Vod is a differential voltage signal between the CAN high signal CANH and the CAN low signal CANL, indicating that (Vod=CANH−CANL). As illustrated in the waveforms inFIG.5, the CAN high signal CANH is depicted by a solid line, while the CAN low signal CANL is depicted by a dashed line.

As we can see fromFIG.5waveforms, at t=t1, the transmit (TX) data signal TXD sends a dominate signal to the transmitter module, and the fourth control signal G4and the fifth control signal G5respectively turns on the fourth transistor TX4-N and the fifth transistor TX5-N. As a result, it starts to drive the CAN bus differential voltage Vod (CANH−CANL) to a high voltage level, for instance, 2V. And at this point of time, it starts to drive the CAN bus differential voltage Vod entering in a dominate state, which is labeled as “D” inFIG.5.

And then, at t-t2, the transmit (TX) data signal TXD sends a recessive signal to the transmitter module, and the fourth control signal G4starts to turn off the fourth transistor TX4-N while the fifth transistor TX5-N is stilled turned on. At the same time, the sixth control signal G6starts to turn on the sixth transistor TX6-P. As a result, it is believed that the sixth transistor TX6-P performs to start pumping out the current of the fifth transistor TX5-N so that the CAN bus enters in a recessive state, which is labeled as “R” inFIG.5.

Later on, during t2<t<t3 (illustrated as “Tactrec” inFIG.5), that is called an active recessive state. In such a period of time during Tactrec, it is believed that the current of the fifth transistor TX5-N fully flows to the sixth transistor TX6-P, such that there is no current flowing to the CAN bus. As a result, it is obvious that due to the above-disclosed mechanism, the CAN bus differential voltage Vod is reduced to zero. And after that, the fifth transistor TX5-N and the sixth transistor TX6-P will be turned off respectively by the fifth control signal G5and the sixth control signal G6slowly after t-t3.

To be more specific, since the voltage of the second joint node N2is biased by the fifth transistor TX5-N and the sixth transistor TX6-P actively and the input resistance (Ri) of the CAN bus is also decided by the fifth transistor TX5-N and the sixth transistor TX6-P and believed to be controlled in a low impedance state when the CAN bus transits from the dominant state “D” to the recessive state “R” and also in the active recessive state, as a result, it is well proven that by employing the proposed scheme of the present invention, the disclosed circuit diagram proposed by the present invention effectively and significantly achieves in suppressing the conventional ringing phenomenon.

Furthermore, since a glitch of the CAN high signal CANH and the CAN low signal CANL may affect electromagnetic emission directly, in order to reduce the glitch of (CANH+CANL), the fourth transistor TX4-N, the fifth transistor TX5-N and the sixth transistor TX6-P of the CANL driver circuit104can be made of one or more transistors. By sequentially turning on the at least one fourth transistor TX4-N, the at least one fifth transistor TX5-N and the at least one sixth transistor TX6-P, it is believed that the present invention is able to further achieve in reducing the glitch of (CANH+CANL) and a superior electromagnetic emission (EME) performance can thus be maintained.

In the following paragraphs, the Applicant further provideFIG.6andFIG.7for demonstrating when the proposed ringing suppression circuit is applied to the transmitter module in the controller area network and is operating under a plurality of various level phase modes. Please refer toFIG.6first, in which a plurality of signal waveforms are shown, depicting the transmit (TX) data signal TXD, the first control signal G1, the second control signal G2, the third control signal G3, the CAN high signal CANH, the CAN low signal CANL and the CAN bus differential voltage Vod, in view of the CANH driver circuit when the proposed ringing suppression circuit is applied to the transmitter module in the controller area network in accordance with the embodiment as shown inFIG.3of the present invention. As described previously, the first control signal G1is transmitted to a gate terminal of the first transistor TX1-P and the first control signal G1is used to control and turn on the first transistor TX1-P. The second control signal G2is transmitted to a gate terminal of the second transistor TX2-P and the second control signal G2is used to control and turn on the second transistor TX2-P. The third control signal G3is transmitted to a gate terminal of the third transistor TX3-N and the third control signal G3is used to control and turn on the third transistor TX3-N.

On the other hand,FIG.7similarly shows a plurality of signal waveforms in view of the CANL driver circuit when the proposed ringing suppression circuit is applied to the transmitter module in the controller area network in accordance with the embodiment as shown inFIG.3of the present invention, indicating a various operating level phase. As can be seen, the fourth control signal G4is transmitted to a gate terminal of the fourth transistor TX4-N and the fourth control signal G4is used to control and turn on the fourth transistor TX4-N. The fifth control signal G5is transmitted to a gate terminal of the fifth transistor TX5-N and the fifth control signal G5is used to control and turn on the fifth transistor TX5-N. The sixth control signal G6is transmitted to a gate terminal of the sixth transistor TX6-P and the sixth control signal G6is used to control and turn on the sixth transistor TX6-P.

The CAN high signal CANH and the CAN low signal CANL are generated respectively at the first end of the termination component106and at the second end of the termination component106. And, the CAN bus differential voltage Vod is a differential voltage signal between the CAN high signal CANH and the CAN low signal CANL, indicating that (Vod=CANH−CANL). As illustrated in the waveforms in both theFIG.6and theFIG.7, the CAN high signal CANH will be depicted by a solid line, while the CAN low signal CANL will be depicted by a dashed line.

As we can see from the transmitter (TX) data signal TXD, before t-t4, the transmitter only transmits the CAN-FD signal, in which it is known that “CAN-FD” (Controller Area Network Flexible Data-Rate) is an extension to the original CAN bus protocol that was specified in ISO 11898-1. Later, after t=t4, the transmitter starts to work in a Fast-TX mode, which allows to transmit more payload with a transmission speed faster than 10 Mbps. (CAN-XL). As known, CAN-XL (Controller Area Network Extra Long) is the third generation of CAN data link layer which supports all three protocol types, including: a Classical CAN mode, a CAN-FD mode, and a CAN-XL mode. The CAN-XL mode is based on the concepts as specified in ISO 11898-1:2015. Since the CiA SIG (Special Interest Group) in December 2018, CAN-XL is specifying the CAN-XL protocol features.

And then, when t is between t4 and t5 (during t4<t<t5), the transmit (TX) data signal TXD is logic 0 and the transmitter enters a level 1 phase “L1”, replacing a dominate state in CAN-FD. During the level 1 phase “L1”, the first transistor TX1-P, the third transistor TX3-N, the fourth transistor TX4-N and the sixth transistor TX6-P will be turned off while the second transistor TX2-P and the fifth transistor TX5-N will be turned on, such that a smaller CAN bus differential voltage Vod will be generated. It is also known that such a smaller CAN bus differential voltage Vod in Fast TX mode is less than a typical Vod in SIC mode, which is one of operating mode in CAN-XL.

And subsequently, when t is between 15 and t6 (during t5<t<t6), the transmit (TX) data signal TXD turns to logic 1 and the transmitter enters a level 0 phase “L0”, replacing a recessive state in CAN-FD. During the level 0 phase “L0”, the first transistor TX1-P, the second transistor TX2-P, the fourth transistor TX4-N and the fifth transistor TX5-N will be turned off while the third transistor TX3-N and the sixth transistor TX6-P will be turned on. As a result, it can be seen that, the generated CAN bus differential voltage Vod obtained in the level 0 phase “L0” will have an opposite polarity to its previous polarity as in the level 1 phase “L1”.

In addition, as we can observe from the two waveform diagrams shown inFIG.6andFIG.7, since either when the driver is operating in the level 1 phase “L1” or in the level 0 phase “L0”, the driver is always on. And therefore, there will be no transition period between these two phases: the level 0 phase “L0” and the level 1 phase “L1”. In other words, according to the disclosed invention of the application, the impedance of the driver can be made and controlled to be extremely low, and can be designed in a fixed value in order to reduce the ringing issue caused due to an impedance mismatch. The proposed present invention is thus believed to be effective in reducing and suppressing the conventional ringing problems.

In view of the above-mentioned verification results and waveforms to be provided, as CAN bus speeds have greatly increased in the recent years, the conventional ringing issue has also increased. As a CAN bus transceiver transitions from a “dominant state” to a “recessive state”, reflections from improperly terminated stubs may cause ringing on the transceiver. And when the magnitude of the ringing is high enough, a transceiver will misinterpret the ringing as a dominant bit. As such, the unwanted ringing phenomenon has been known to cause bit errors. In order to solve the foregoing deficiency, the present invention is thus provided, and in view of the above-mentioned technical contents of the present invention, it is believed that ringing on the controller area network bus due to improper electrical termination can be successfully eliminated and suppressed by using the disclosed ringing suppression circuit of the present invention.

Please proceed to refer toFIG.8, which schematically shows an illustrative diagram when a receiver module of the controller area network is further employed so as to generate a receive (RX) data signal. As can be seen inFIG.6, it discloses that by employing the present invention, since ringing on the controller area network bus is effectively suppressed, the CAN high signal CANH and the CAN low signal CANL can be further transmitted and received by a receiver module306of the controller area network, such that the receiver module306outputs a receive (RX) data signal RXD without generating bit errors.

Hereinafter, according to the technical contents of the present invention which have been provided by the Applicants as illustrated in the previous paragraphs, it is obvious that the ringing suppression circuit is effective. Meanwhile, a maximum data rate of the controller area network bus is accomplished by adopting the present invention. Therefore, in view of all, it is obvious that the present invention is not only novel and inventive but also believed to be advantageous of solving and avoiding the conventional ringing phenomenon.

As a result, when compared to the prior arts, it is ensured that the present invention apparently shows much more effective performances than before. In addition, it is believed that the present invention is instinct, effective and highly competitive for IC technology and industries in the market nowadays, whereby having extraordinary availability and competitiveness for future industrial developments and being in condition for early allowance.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the invention and its equivalent.