Patent Application
20130214818
This application claims priority to Taiwan Patent Application Serial Number 101105184, filed Feb. 17, 2012, which is herein incorporated by reference.
1. Technical Field
The present disclosure relates to a protection circuit. More particularly, the present disclosure relates to a protection circuit and a method applicable to an electrical apparatus.
2. Description of Related Art
A protection circuit for a conventional electrical apparatus acquires a corresponding sensing signal by detecting various output signals outputted by the electrical apparatus, and then the protection circuit compares the sensing signal with a reference signal by way of software or hardware to determine whether the electrical apparatus is overloaded or not.
For example,
The comparison unit 120 is configured to compare the sensing signal corresponding to the output signal outputted by the electrical apparatus, with the reference voltage level. When the output of the electrical apparatus is overloaded, the sensing signal reaches to the reference voltage level, and the comparison unit 120 outputs a corresponding comparison result to the processing unit 130. Thus, the processing unit 130 generates error information and stops outputting a control signal in order to switch off the electrical apparatus and to perform the function of circuit overload protection.
However, if the level of the sensing signal exceeds the reference voltage level because of extrinsic transient noise, the protection circuit 100 still generates the error information and stops outputting the control signal to further switch off the electrical apparatus, thus resulting in a false action of the electrical apparatus. Moreover, the protection circuit 100 has to be equipped with the reference voltage generating circuit 110, thus increasing the cost for circuit design.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.
An aspect of the present disclosure is related to a protection circuit. The protection circuit includes a digital-to-analog (D/A) converter unit, a comparison unit, and a processing unit. The digital-to-analog converter unit is configured for outputting an analog reference signal having a first level. The comparison unit is electrically coupled to the digital-to-analog converter unit and configured to compare a sensing signal with the analog reference signal, in which the comparison unit outputs a comparison signal when a level of the sensing signal is higher than or equal to the first level. The processing unit is electrically coupled to the digital-to-analog converter unit and the comparison unit, and the processing unit is configured to generate an enable signal for activating a control circuit and configured to receive the comparison signal to output an interrupt signal for temporarily deactivating the control circuit. When the control circuit is activated again by the enable signal after being temporarily deactivated, the processing unit outputs a level modulation signal to the digital-to-analog converter unit, and the digital-to-analog converter unit modifies the outputted analog reference signal according to the level modulation signal.
Another aspect of the present disclosure is related to a method for protecting an electrical apparatus. The method includes the steps as follows. A sensing signal is compared with an analog reference signal, and a comparison signal is generated when a level of the sensing signal is higher than or equal to a level of the analog reference signal. An interrupt signal is generated for temporarily deactivating a control circuit according to the comparison signal. When an enable signal for activating the control circuit is generated after the control circuit is temporarily deactivated, a level modulation signal is generated. The level of the analog reference signal is modified according to the level modulation signal.
It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the disclosure as claimed.
The disclosure can be more fully understood by reading the following detailed description of the embodiments, with reference to the accompanying drawings as follows:
In the following description, specific details are presented to provide a thorough understanding of the embodiments of the present disclosure. Persons of ordinary skill in the relevant art will recognize, however, that the present disclosure can be practiced without one or more of the specific details, or in combination with other components. Well-known implementations or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the present disclosure.
The terms used in this specification generally have their ordinary meanings in the art and in the specific context where each term is used. The use of examples anywhere in this specification, including examples of any terms discussed herein, is illustrative only, and in no way limits the scope and meaning of the disclosure or of any exemplified term. Likewise, the present disclosure is not limited to various embodiments given in this specification.
As used herein, the terms “comprising,” “including,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, implementation, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, uses of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, implementation, or characteristics may be combined in any suitable manner in one or more embodiments.
In the following description and claims, the terms “coupled” and “connected”, along with their derivatives, may be used. In particular embodiments, “connected” and “coupled” may be used to indicate that two or more elements are in direct physical or electrical contact with each other, or may also mean that two or more elements may not be in direct contact with each other. “Coupled” may still be used to indicate that two or more elements cooperate or interact with each other.
In addition, the protection circuit 300 includes an input terminal 350, a first output terminal 360 and a second output terminal 370, in which the input terminal 350 is configured to receive a sensing signal, and the sensing signal is an analog signal corresponding to at least one of a detected voltage signal, a detected current signal, a detected power signal and a detected temperature signal. The first output terminal 360 is connected to a control circuit 365, and the second output terminal 370 is connected to a user interface.
As shown in
Furthermore, when the control circuit 365 is activated again by the enable signal after being temporarily deactivated, the processing unit 330 outputs a level modulation signal to the digital-to-analog converter unit 310 through a feedback path 380, and the digital-to-analog converter unit 310 modifies the outputted analog reference signal according to the level modulation signal.
In practice, the digital-to-analog converter unit 310 and the comparison unit 320 can be implemented in the form of circuits or by way of other hardwares (for example, a digital-to-analog converter circuit and a comparator circuit), and the processing unit 330 can be implemented by way of hardware with software; however, the present disclosure is not limited thereto.
In one preferred embodiment, the digital-to-analog converter unit 310, the comparison unit 320 and the processing unit 330 are integrated in a micro-controller or a micro-controller unit (MCU). Therefore, the analog signal can be processed by the digital-to-analog converter unit 310 and the comparison unit 320 in the micro-controller, such that the speed of processing signals can be increased for allowing the abnormal operation (e.g., over-voltage, over-current, etc.) to be instantly and efficiently determined by the processing unit 330, and then the processing unit 330 can rapidly interrupt the operation of the control circuit 365 or further switch off (or shuts down) the control circuit 365 to prevent the control circuit 365 from being damaged and to avoid causing damages to the entire system.
In another preferred embodiment, the aforementioned protection circuit 300 is implemented by using a micro-controller; that is, the mechanism that the protection circuit 300 determines the sensing signal to further protect the entire system, is directly implemented by the micro-controller.
In operation, when an abnormal condition (e.g., over-current) occurs, the comparison unit 320 accordingly outputs the comparison signal (i.e., the signal having a high logic level), and meanwhile the predetermined threshold signal (e.g., a high logic level signal corresponding to the threshold current value of 900 amps) is also generated correspondingly. Then, the AND gate 335 performs a logical operation with respect to the comparison signal and the predetermined threshold signal to generate the corresponding high logic level signal as the interrupt signal, thereby temporarily deactivating the external control circuit and its operation, or further temporarily deactivating the operation of the entire system.
It is noted that, the comparison signal also can be directly outputted as the interrupt signal without being processed by the processing unit 330, so as to temporarily deactivate the external control circuit and its operation, or to further temporarily deactivate the operation of the entire system.
In another preferred embodiment, the processing unit 330 determines whether or not to output a switch-off signal for switching off the control circuit 365 to completely stop the operation of the control circuit 365 (or the entire system) according to a number of times of receiving the comparison signal. Specifically, the processing unit 330 outputs the level modulation signal to the digital-to-analog converter unit 310, and the digital-to-analog converter unit 310 modifies the outputted analog reference signal according to the level modulation 25. such that the analog reference signal has different levels. Then, the comparison unit 320 compares the sensing signal with the analog reference signal, and also outputs the comparison signal when the level of the sensing signal is higher than or equal to the level of the analog reference signal. The processing unit 330 then outputs the interrupt signal for temporarily deactivating the control circuit 365 according to the comparison signal. The above steps are repeated analogously, and the processing unit 330 further determines the number of times of receiving the comparison signal, and outputs the switch-off signal for switching off the control circuit 365 when the number of times of receiving the comparison signal reaches to a predetermined number of times (e.g., 3 times). In this situation, the electrical apparatus 50 is shut down.
In still another preferred embodiment, when the processing unit 330 outputs the switch-off signal for switching off the control circuit 365, the processing unit 330 outputs an error signal through the second output terminal 370 for audio warning or a display on a user interface to inform a user.
As a result, the control circuit 365 can be temporarily deactivated by the interrupt signal in advance to determine whether the abnormal condition actually occurs, or whether the abnormal condition is caused by noise and surge interference, and the control circuit 365 or the entire system is directly switched off (or shut down) after the abnormal condition is confirmed and the control circuit 365 is temporarily deactivated for several times, thereby preventing the control circuit 365 or the entire system from being damaged due to continuous operation.
Hereinafter, one embodiment of the present disclosure is used to explain the operation of the protection circuit 300 shown in
Then, at time point t2, when an abnormal condition (e.g., over-current) occurs, the level of the corresponding sensing signal rises to be equal to or higher than a first warning level, and the comparison unit 320 correspondingly outputs the comparison signal at the moment, and the processing unit 330 correspondingly outputs the interrupt signal (i.e., a low level signal) to temporarily deactivate the operation of the control circuit 365 or the entire system.
It is noted that, a high-level state and a low-level state of the same control signal may represent the enable signal and the interrupt signal respectively, but different signals may also be configured as the enable signal and the interrupt signal, respectively, according to practical needs. Moreover, in a predetermined time period after the processing unit 330 outputs the interrupt signal, the processing unit 330 resumes outputting the enable signal (at time point t3).
In addition, at time point t3, the processing unit 330 outputs the level modulation signal to the digital-to-analog converter unit 310 through the feedback path 380, and the digital-to-analog converter unit 310 modifies the outputted analog reference signal according to the level modulation signal, such that the analog reference signal has a second warning level, and the second warning level is higher than the first warning level.
The comparison unit 320 then compares the sensing signal with the analog reference signal having the second warning level. Afterward, at time point t4, when the abnormal condition (e.g., over-current) occurs again, the level of the corresponding sensing signal rises to be equal to or higher than the second warning level, and the comparison unit 320 correspondingly outputs the comparison signal at the moment, and the processing unit 330 correspondingly outputs the interrupt signal (i.e., the low level signal) to temporarily deactivate the operation of the control circuit 365 or the entire system.
It is noted that, if the processing unit 330 determines that the number of times of receiving the comparison signal reaches to a predetermined number of times (e.g., 2 times) at the moment, the processing unit 330 may be switched to output the switch-off signal (i.e., the low level signal) to switch off the control circuit 365, and the processing unit 330 resumes outputting the enable signal in a predetermined time period after the processing unit 330 outputs the interrupt signal, in which the time period can be predetermined in the processing unit 330 to achieve the effect of resuming generating the enable signal.
On the other hand, in the condition of the processing unit 330 determining that the number of times of receiving the comparison signal reaches to a predetermined number of times (e.g., 3 times), at time point t5, the processing unit 330 outputs the level modulation signal to the digital-to-analog converter unit 310 through the feedback path 380 again, and the digital-to-analog converter unit 310 modifies the outputted analog reference signal according to the level modulation signal again, such that the analog reference signal has a third warning level, and the third warning level is higher than the second warning level.
The comparison unit 320 then compares the sensing signal with the analog reference signal having the third warning level again. Afterward, at time point t6, when the abnormal condition occurs again, the level of the corresponding sensing signal rises to be equal to or higher than the third warning level, and the comparison unit 320 correspondingly outputs the comparison signal at the moment. The processing unit 330 determines that the number of times of receiving the comparison signal reaches to the predetermined number of times (e.g., 3 times), and the processing unit 330 outputs the switch-off signal (i.e., the low level signal) to switch off (or shut down) the operation of the control circuit 365 or the entire system according to the comparison signal.
It is noted that, different low-level states (e.g., different durations of low-level states) of the same control signal may represent the interrupt signal and the switch-off signal, respectively, but different signals may also be configured as the interrupt signal and the switch-off signal, respectively, according to practical needs.
Moreover, when the operation of the control circuit 365 or the entire system is switched off, the processing unit 330 may also output the error signal through the second output terminal 370 to a user interface or an operation interface, thereby informing a system side of the abnormal condition that has already occurred.
On the other hand, in some preferred embodiments, the processing unit 330 generates the level modulation signal for the digital-to-analog converter unit 310 by way of a software configuration, or the processing unit 330 flexibly generates the level modulation signal by way of a dynamic learning mechanism (e.g., neural control or fuzzy control) or an experience accumulation mechanism. The termed dynamic learning mechanism and experience accumulation mechanism herein indicate that the level modulation signal is generated by way of software incorporating environment parameters, predetermining a number of reference levels, utilizing a look-up table (LUT) or collaborating with the mechanisms such as the neural control or the fuzzy control, so as to achieve the effect of outputting a best reference level. Therefore, the aforementioned manner can be used for allowing the analog reference signal to be flexibly modified or relaxed to exclude the misjudgment of the abnormal operation caused by transient noise.
When the level of the sensing signal is lower than the level of the analog reference signal, an enable signal is continuously generated for a control circuit (e.g., a pulse width modulation control circuit) (Step 706), and the operation returns back to Step 704 so that whether the level of the sensing signal is higher than or equal to the level of the analog reference signal is determined again. When the level of the sensing signal is higher than or equal to the level of the analog reference signal (e.g., the voltage, current or temperature is too high in the abnormal condition), a comparison signal is generated (Step 708), and an interrupt signal is generated for temporarily deactivating the control circuit according to the comparison signal (Step 710).
Afterward, when the generation of the enable signal for activating the control circuit is resumed in a predetermined time period after the control circuit is temporarily deactivated, a level modulation signal is generated (Step 712), and then the level of the analog reference signal is modified according to the level modulation signal (Step 714), such that the analog reference signal can further be compared with the sensing signal again. Then, after the level of the analog reference signal is modified, the operation returns back to Step 702, and Step 702 through Step 714 are performed again, which may be deduced by analogy.
It is noted that, after Step 702 through Step 714 are performed repeatedly for several times, a switch-off signal for switching off the control circuit (or the entire system) may also be generated according to the comparison signal after Step 708, so as to finish the aforementioned process. Furthermore, the time period can be predetermined in a processing unit to achieve the effect of resuming generating the enable signal.
On the other hand, in the embodiments as shown in
Furthermore, in the embodiments as shown in
Moreover, the protection method as shown in
Compared to prior art, in the embodiments of the present disclosure, the digital-to-analog converter unit (e.g., digital-to-analog converter circuit) and the comparison unit (e.g., comparator circuit) can be integrated and built in the micro-controller without increasing the cost of circuits, so as to process analog signals via the digital-to-analog converter unit and the comparison unit, such that the speed of processing signals can be increased, and the abnormal operation (e.g., over-voltage, over-current, etc.) can be instantly and efficiently confirmed to further interrupt the operation of the control circuit outside the micro-controller, or to further switch off (or shuts down) the control circuit, thus preventing the control circuit from being damaged and avoiding causing damages to the entire system.
In addition, the level of the analog reference signal outputted by the digital-to-analog converter unit can further be flexibly modified by way of the dynamic learning mechanism or the experience accumulation mechanism in the aforementioned protection circuit, such that the electrical apparatus can generate fine tuning output signals according to different application environments. Moreover, using digital feedback to modify the level of the analog reference signal outputted by the digital-to-analog converter unit can decrease the complexity of circuits and reduce the reference level shift caused by deviations of fabrication process or devices.
Furthermore, the software and hardware protection mechanisms both are configured in the present disclosure, such that the operation of the control circuit can be temporarily deactivated by the output of the hardware immediately when the error occurs, and then the reference level is gradually modified and relaxed by way of software configuration, to confirm whether the abnormal condition certainly occurs, or whether the abnormal condition is caused by noise and surge interference, and the control circuit or the entire system is directly switched off (or shut down) after the abnormal condition is confirmed and the control circuit is temporarily deactivated for several times, to prevent the control circuit or the entire system from operating continuously to be damaged.
The steps are not necessarily recited in the sequence in which the steps are performed. That is, unless the sequence of the steps is expressly indicated, the sequence of the steps is interchangeable, and all or part of the steps may be simultaneously, partially simultaneously, or sequentially performed.
As is understood by a person skilled in the art, the foregoing embodiments of the present disclosure are illustrative of the present disclosure rather than limiting of the present disclosure. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101105184 | Feb 2012 | TW | national |
