Detection circuit and electronic equipment

Abstract

The utility model relates to the technical field of electronics, in particular to a detection circuit and electronic equipment. The detection circuit comprises a control circuit, a resistor unit and a filter circuit, the output end of the control circuit is connected to one end of the resistor unit, and the other end of the resistor unit is connected to the input end of the filter circuit; the input end of the control circuit outputs a voltage signal to one end of the resistor unit under the condition that the received control signal is effective; the input end of the filter circuit outputs a detection result signal under the condition that a first signal to be detected is received; wherein when the first signal is a PWM wave signal, the voltage value of the detection result signal is between the high level and the low level of the PWM wave signal; when the first signal is grounded, the detection result signal voltage value is 0; when the first signal is connected to a DC voltage signal whose voltage value is higher than the high level of the PWM wave signal, the voltage value of the detection result signal is the voltage value of the DC voltage signal. Based on the detection circuit, whether the PWM wave signal to be detected is abnormal can be detected.

Description

Technical Field

[0001] This application relates to the field of electronic technologies, and in particular, to a detection circuit and an electronic device. Background Art

[0002] With the development of digital processing technologies, digital signals are increasingly widely used in electronic devices (such as vehicles and industrial equipment). In an electronic device, information is usually transmitted through signals with different frequencies (such as pulse width modulation (PWM) signals). However, if the cable used to transmit the PWM signal is short-circuited to ground or power supply, the processing circuit that receives the PWM signal will receive incorrect information, affecting the further operation of the processing circuit.

[0003] For example, instruments in a vehicle (such as a dimming device, a horn, and a temperature control device, etc.) can transmit detected sensor data, fault data, abnormal data, etc. to the vehicle controller through PWM signals. The vehicle controller can control the vehicle to perform related operations (such as prompting the user, braking, steering, etc.) based on the received PWM signals. If the PWM signal output by the instrument is short-circuited to ground or power supply due to a line fault or other reasons, the controller will detect incorrect data, affecting the safety of the vehicle. Summary of the Utility Model

[0004] An embodiment of this application provides a detection circuit, which can be used to detect whether a PWM signal is abnormal, for example, to detect whether the PWM signal is grounded or connected to other DC signals. In this way, incorrect data detected by the controller can be avoided, improving the safety of the vehicle.

[0005] In a first aspect, this application provides a detection circuit, which includes a control circuit, a resistance unit, and a filtering circuit. The output end of the control circuit is connected to one end of the resistance unit, and the other end of the resistance unit is connected to the input end of the filtering circuit. When the control signal received at the input end of the control circuit is valid, the control circuit outputs a voltage signal to one end of the resistance unit. When the input end of the filtering circuit receives a first signal to be detected, the filtering circuit outputs a detection result signal corresponding to the first signal through the output end of the filtering circuit, where: corresponding to the first signal being a PWM wave signal, the voltage value of the detection result signal is the voltage value between the high level and the low level of the PWM wave signal; corresponding to the first signal being grounded, the voltage value of the detection result signal is 0; corresponding to the first signal being connected to a DC voltage signal, the voltage value of the detection result signal is the voltage value of the DC voltage signal, where the voltage value of the DC voltage signal is higher than the high level of the PWM wave signal.

[0006] Based on the above detection circuit, it is possible to detect whether the first signal to be detected (such as a PWM wave signal) is abnormal. For example, when the voltage value of the detection result signal is between the high level and the low level of the PWM wave signal, it is determined that the PWM signal is normal; otherwise, it is determined that the PWM signal is abnormal. In this way, the controller is prevented from detecting incorrect data, improving the safety of the vehicle.

[0007] In this implementation, the control circuit can be the control circuit 30 in the following text, the filtering circuit can be the filtering circuit 40 in the following text, and the resistor unit can be the resistor unit 60 in the following text. The input terminal of the control circuit can be the control input terminal 31 in the following text, and the output terminal of the control circuit can be the output terminal 33 in the following text. The input terminal of the filtering circuit can be the input terminal 34 in the following text, and the output terminal of the filtering circuit can be the output terminal 35 in the following text.

[0008] In a possible implementation of the first aspect above, the control circuit includes a first triode. The emitter of the first triode is connected to the power supply, the base of the first triode is connected to the input terminal of the control circuit, and the collector of the first triode is connected to the output terminal of the control circuit. When the voltage corresponding to the control signal input to the input terminal of the control circuit satisfies the conduction condition of the first triode (for example, when the first triode is an N-type triode, the voltage corresponding to the control signal input to the base is greater than the conduction voltage of the first triode; when the first triode is a P-type triode, the voltage corresponding to the control signal input to the base is less than the conduction voltage of the first triode), the first triode conducts, and outputs a voltage signal to the output terminal of the control circuit through the collector, and the control circuit is turned on to enable the detection of the PWM signal.

[0009] In this implementation, the first triode can be the triode 70 in the following text.

[0010] In this implementation, the opening and closing of the detection circuit can be achieved through the first triode, which is beneficial to reducing costs.

[0011] In this implementation, the control signal being valid can mean that the control signal can cause the first triode to conduct.

[0012] In a possible implementation of the first aspect above, the control circuit further includes a first diode, and the collector of the first triode is connected to the output terminal of the control circuit through the first diode. The anode of the first diode is connected to the collector of the first triode, and the cathode of the first diode is connected to the output terminal of the control circuit. Here, the anode of the first diode is connected to the collector of the first triode and the cathode is connected to the output terminal of the control circuit. In this way, it is possible to prevent the first triode from being broken down due to the too-high voltage of the PWM signal to be detected.

[0013] In this implementation, the first diode can be the diode D1 in the following text.

[0014] In this implementation, it is possible to avoid breakdown of the first triode due to an excessively high first signal voltage.

[0015] In a possible implementation of the first aspect above, the control circuit includes a second triode, a third triode, and a first resistor unit; wherein, the emitter of the second triode is grounded, the base of the second triode is connected to the input end of the control circuit, and the collector of the second triode is connected to one end of the first resistor unit; the other end of the first resistor unit is connected to the base of the third triode; the emitter of the third triode is connected to the power supply, and the collector of the third triode is connected to the output end of the control circuit.

[0016] When the voltage of the control signal input to the base of the second triode satisfies the conduction condition of the second triode (for example, when the second triode is an N-type, the voltage corresponding to the control signal input to the base of the second triode is greater than the conduction voltage of the second triode, and when the second triode is a P-type, the voltage corresponding to the control signal input to the base of the second triode is less than the conduction voltage of the second triode), the second triode conducts, and a voltage is input to the base of the third triode through the first resistor unit; when the voltage input to the base of the third triode satisfies the conduction condition of the third triode (for example, when the third triode is an N-type, the voltage corresponding to the control signal input to the base of the third triode is greater than the conduction voltage of the third triode, and when the third triode is a P-type, the voltage corresponding to the control signal input to the base of the third triode is less than the conduction voltage of the third triode), the third triode conducts, the control circuit is turned on, and a voltage signal is output to the output end of the control circuit to enable the detection of the PWM signal.

[0017] In this implementation, the second triode can be the triode 80 in the following text, and the third triode can be the triode 90 in the following text.

[0018] In this implementation, the validity of the control signal can be that the control signal can cause the second triode and the third triode to conduct.

[0019] In a possible implementation of the first aspect above, the control circuit further includes a second diode, and the collector of the third triode is connected to the output end of the control circuit through the second diode, wherein the anode of the second diode is connected to the collector of the third triode, and the cathode of the second diode is connected to the output end of the control circuit.

[0020] In this implementation, the second diode can be the diode D2 in the following text.

[0021] In this implementation, it is possible to avoid breakdown of the third triode due to an excessively high first signal voltage.

[0022] In a possible implementation of the above first aspect, the control circuit includes a field-effect transistor. The gate of the field-effect transistor is connected to the input end of the control circuit, the drain of the field-effect transistor is connected to the power supply, and the source of the field-effect transistor is connected to the output end of the control circuit. When the voltage of the control signal input to the gate of the field-effect transistor is greater than the turn-on voltage of the field-effect transistor (i.e., when the control signal is valid), the field-effect transistor conducts, outputs a voltage signal to the output end of the control circuit, the control circuit is turned on, and the detection of the PWM signal is enabled.

[0023] In this implementation manner, the validity of the control signal can be that the control signal can cause the field-effect transistor to conduct.

[0024] In a possible implementation of the above first aspect, the filtering circuit includes a second resistor unit and a first capacitor unit; wherein: one end of the second resistor unit is connected to the input end of the filtering circuit, the other end of the second resistor unit is connected to one end of the first capacitor unit and the output end of the filtering circuit, and the other end of the first capacitor unit is grounded. When the signal input to the input end of the filtering circuit is a DC signal, the voltage value of the detection result signal output by the filtering circuit through the output end of the filtering circuit is the voltage value of this DC signal. When the signal input to the input end of the filtering circuit is a PWM signal, the voltage value of the detection result signal output by the filtering circuit through the output end of the filtering circuit is between the high level and the low level of this PWM signal.

[0025] In this implementation manner, the first capacitor unit can be the capacitor unit 120 in the following text, and the second resistor unit can be the resistor unit 110 in the following text.

[0026] In a possible implementation of the above first aspect, the filtering circuit includes a third resistor unit and a second capacitor unit, a fourth resistor unit and a third capacitor unit; wherein: one end of the third resistor unit is connected to the input end of the filtering circuit, the other end of the third resistor unit is connected to one end of the second capacitor unit and one end of the fourth resistor unit, the other end of the fourth resistor unit is connected to one end of the third capacitor unit and the output end of the filtering circuit, and the other ends of the second capacitor unit and the third capacitor unit are grounded. When the signal input to the input end of the filtering circuit is a DC signal, the voltage value of the detection result signal output by the filtering circuit through the output end of the filtering circuit is the voltage value of this DC signal. When the signal input to the input end of the filtering circuit is a PWM signal, the voltage value of the detection result signal output by the filtering circuit through the output end of the filtering circuit is between the high level and the low level of this PWM signal.

[0027] In this implementation manner, the third resistor unit can be the resistor unit 140 in the following text, the third resistor unit can be the resistor unit 150 in the following text, the second capacitor unit can be the capacitor unit 160 in the following text, and the third capacitor unit can be the capacitor unit 170 in the following text.

[0028] In a possible implementation of the above first aspect, the filtering circuit includes N filtering units, each filtering unit includes a resistor unit and a capacitor unit, one end of a resistor unit in each filtering unit is connected to one end of a capacitor unit, the other end of a capacitor unit is grounded, and N is an integer greater than 2; where: the other end of a resistor unit in the first filtering unit among the N filtering units is connected to the input end of the filtering circuit; one end of a resistor unit in the i-th filtering unit among the N filtering units is further connected to the other end of a resistor unit in the (i + 1)-th filtering unit among the N filtering units, and i is an integer greater than or equal to 1 and less than N; one end of a resistor unit in the N-th filtering unit among the N filtering units is further connected to the output end of the filtering circuit. When the signal input at the input end of the filtering circuit is a DC signal, the voltage value of the detection result signal output by the filtering circuit through the output end of the filtering circuit is the voltage value of the DC signal. When the signal input at the input end of the filtering circuit is a PWM signal, the voltage value of the detection result signal output by the filtering circuit through the output end of the filtering circuit is between the high level and the low level of the PWM signal.

[0029] In a possible implementation of the above first aspect, the detection circuit further includes a controller, and the controller is connected to the output end of the filtering circuit; when the voltage value of the detection result signal received by the controller from the output end of the filtering circuit is between the high level and the low level of the PWM wave signal, the controller determines that the first signal is normal; when the voltage value of the detection result signal received by the controller from the output end of the filtering circuit is greater than the high level of the PWM signal or is 0, the controller determines that the first signal is abnormal.

[0030] In a second aspect, an embodiment of the present application provides an electronic device, and the electronic device includes any one of the detection circuits provided in the above first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 According to some embodiments of the present application, a schematic diagram of a scenario where a detection device in a vehicle 1 transmits a PWM signal to a controller is shown.

[0032] Figure 2 According to some embodiments of the present application, a schematic diagram of a detection circuit 50 is shown.

[0033] Figure 3A According to some embodiments of the present application, a schematic diagram of a specific circuit of a detection circuit 50 is shown.

[0034] Figure 3B According to some embodiments of the present application, a schematic diagram of another specific circuit of a detection circuit 50 is shown.

[0035] Figure 3C According to some embodiments of the present application, a schematic diagram of a specific circuit of another detection circuit 50 is shown.

[0036] Figure 3D According to some embodiments of the present application, a schematic diagram of a specific circuit of yet another detection circuit 50 is shown.

[0037] Figure 3E According to some embodiments of the present application, a schematic diagram of a specific circuit of still another detection circuit 50 is shown.

[0038] Figure 4A According to some embodiments of the present application, a schematic diagram of a specific circuit of a filtering circuit 50 is shown.

[0039] Figure 4B According to some embodiments of the present application, a schematic diagram of a specific circuit of another filtering circuit 50 is shown. Detailed implementation manners

[0040] Illustrative embodiments of the present application include but are not limited to a detection circuit and an electronic device.

[0041] It can be understood that the technical solutions provided by the embodiments of the present application can be applied to any device / device / circuit that outputs a PWM signal, including but not limited to automotive dimming devices, speakers and temperature control devices, vehicles, instruments in vehicles, etc.

[0042] In some embodiments, in an automotive instrument, a detection device sends a PWM signal to a controller. The cable for transmitting the PWM signal may be wrongly grounded or short-circuited to the circuit supply voltage (Volt Current Condenser, VCC) (such as a power supply), so short-circuit monitoring is required for it. Generally, a current-limiting resistor can be used for ordinary high and low level signals. However, the PWM signal has a relatively high frequency (from several hundred hertz to several megahertz) and a large variation in signal amplitude (from 1 volt to 16 volts), so a current-limiting resistor cannot be used for short-circuit monitoring.

[0043] For example, Figure 1 According to some embodiments of the present application, a schematic diagram of a scenario where a detection device in a vehicle 1 transmits a PWM signal to a controller is shown.

[0044] As Figure 1 shown, the vehicle 1 includes at least one detection device 10 and a controller 20. Each detection device 10 can transmit the detected data to the controller 20 in the form of a PWM signal. The controller 20 can perform corresponding operations based on the received PWM signal, such as dimming, adjusting the speaker, adjusting the temperature, controlling the vehicle (such as braking, steering, speed regulation), etc.

[0045] In some embodiments, the detection device 10 may be a device (such as an electronic temperature and humidity meter) for detecting the temperature and humidity of an automobile and sending the detected temperature and humidity information to the controller 20 via a PWM signal. The detection device 10 can be used to detect the current temperature and current humidity inside the automobile and send the current temperature and current humidity to the controller 20 via a PWM signal. For example, different frequencies or duty cycles of the PWM signal can represent different temperatures or humidities. After receiving the PWM signal, the controller 20 can identify the current temperature and current humidity from different frequencies or duty cycles of the PWM signal and adjust the temperature and humidity inside the vehicle according to the temperature, humidity, etc. set by the user.

[0046] In some embodiments, the detection device 10 may also be a device (such as a tachometer) for detecting the rotational speed of an automobile and sending the detected rotational speed information to the controller 20 via a PWM signal. The detection device 10 can be used to detect the rotational speed of the automobile wheels and send the current rotational speed of the wheels to the controller 20 via a PWM signal. For example, different frequencies or duty cycles of the PWM signal can represent different rotational speeds. After receiving the PWM signal, the controller 20 identifies the rotational speed of the wheels, converts the rotational speed of the wheels into the current vehicle speed, and displays the current vehicle speed or adjusts the vehicle speed according to the current driving environment.

[0047] It should be understood that the device described by taking the detection device 10 for detecting temperature and humidity as an example in the embodiments of the present application is just an example. In some other embodiments, the detection device 10 can be any device for detecting data in a vehicle and sending the detected data to the controller 20 via a PWM signal, such as for detecting the rotational speed of an automobile and for detecting the light intensity around the automobile.

[0048] If the circuit for transmitting the PWM signal is shorted to ground or power supply (such as the interface of the detection device 10 for outputting the PWM signal), it will cause the signal received by the controller 20 to be a low level (such as 0V) or a DC voltage matching the voltage of the power supply. In this way, the signal received by the controller will be incorrect, resulting in the controller being unable to normally execute the command for regulating the parameters of automotive electronic devices, affecting the safety of the vehicle and the user experience.

[0049] To avoid the signal received by the controller from being incorrect when the cable for transmitting the PWM signal is shorted to ground or power supply, the embodiments of the present application provide a detection circuit for detecting whether the PWM signal is shorted to ground or power supply (such as a DC voltage higher than the high level of the PWM signal). As Figure 2 shown, the detection circuit 50 may include a control circuit 30, a resistance unit 60, and a filtering circuit 40.

[0050] The control circuit 30 includes a control input terminal 31, a power input terminal 32, and an output terminal 33. The control input terminal 31 is used to receive a control signal sent by the detection device 10 (which can also be the controller 20 or other modules). The power input terminal is connected to VCC, and the output terminal is connected to one end of the resistor unit 60. The other end of the resistor unit 60 is connected to the PWM signal to be detected and the input terminal of the filter circuit 40. The output terminal of the filter circuit 40 is used to input the detection result to the controller 20.

[0051] The control circuit 30 is used to enable or disable the detection of the PWM signal. When the control signal received by the control circuit 30 at the control input terminal 31 is valid, the control circuit 30 is turned on, enabling the detection of the PWM signal and inputting a voltage signal to the resistor unit 60 to prevent the filter circuit 40 from affecting the PWM signal to be detected. When the control signal received by the control circuit 30 at the control input terminal 31 is invalid, the control circuit 30 is turned off, and the connection between the control circuit 30 and the resistor unit 60 is equivalent to an open circuit, disabling the detection of the PWM signal.

[0052] The filter circuit 40 is used to filter the PWM signal to be detected into a DC signal (as the detection result signal). Assuming that the high level of the PWM output signal is V0 and the low level is V1, the voltage of the detection result signal output by the filter circuit 40 is the voltage value between V0 - V1, and this voltage value is proportional to the duty cycle of the PWM waveform. If the PWM signal is shorted to ground, the voltage of the detection result signal output by the filter circuit 40 is 0; if the PWM signal is shorted to VCC1, the voltage value of the detection result signal output by the filter circuit 40 is VCC1.

[0053] In some embodiments, the low level V0 of the PWM signal to be detected is 0V.

[0054] When it is necessary to detect the PWM signal, the control circuit 30 can input a valid voltage signal to the resistor unit 60 to enable the detection of the PWM signal. After receiving the detection result signal output by the filter circuit 40, the controller 20 can compare the voltage value of the detection result signal with V0 and V1. If the voltage value of the detection result signal is the voltage value between V0 - V1, it indicates that the PWM signal is normal; if the voltage value of the detection result signal is 0, it indicates that the PWM signal is shorted to ground; if the voltage value of the detection result signal is greater than V0 (for example, VCC1), it indicates that the PWM signal is shorted to a DC voltage with a voltage value of VCC1.

[0055] In this way, the detection circuit 50 can output the detection result signal corresponding to the PWM signal to be detected that has passed through the filter circuit 40 to the controller 20, so that the controller 20 can timely determine whether the PWM signal to be detected is shorted to ground or the power supply based on the received detection result signal, and trigger adjustment measures in a timely manner when it is determined that the PWM signal is abnormal.

[0056] In some embodiments, the control circuit may be other circuits including at least one switching device (such as a triode, a Metal Oxide Semiconductor (MOS) transistor, etc.), which is used to enable the operation of the detection circuit in response to an input control signal. For example, when the control signal input at the input end is valid, the operation of the detection circuit is started.

[0057] For example, Figure 3A FIG. shows a schematic diagram of a specific circuit of a detection circuit 50.

[0058] Exemplarily, referring to Figure 3A , the control circuit 30 in the detection circuit 50 may include a triode 70. Wherein, the emitter of the triode 70 is connected to the power input terminal 32 (for example, the power input terminal 32 may be connected to VCC), the base of the triode 70 is connected to the control input terminal 31, and the collector of the triode 70 is connected to the output terminal 33. When the voltage corresponding to the control signal input at the control input terminal 31 of the control circuit 30 is less than the conduction voltage of the triode 70, the triode 70 conducts, and outputs a voltage signal to the aforementioned one end of the resistance unit 60 through the collector. The control circuit 30 is turned on to enable the detection of the PWM signal.

[0059] In other embodiments, if the triode 70 is an N-type triode, the voltage corresponding to the control signal input at the control input terminal of the triode 70 may be greater than the conduction voltage of the triode 70.

[0060] The filtering circuit 40 in the detection circuit 50 may include a resistance unit 110 and a capacitance unit 120. One end of the resistance unit 110 is connected to the input terminal 34 of the filtering circuit 40, the other end of the resistance unit 110 is connected to the output terminal 35 of the filtering circuit 40 and one end of the capacitance unit 120, and the other end of the capacitance unit 120 is grounded.

[0061] It should be understood that the resistance unit in the embodiments of the present application may include one or more resistors, and the one or more resistors may be connected in series, in parallel, or in a combination of series and parallel, which is not limited herein.

[0062] It should be understood that the capacitance unit in the embodiments of the present application may include one or more capacitors, and the one or more capacitors may be connected in series, in parallel, or in a combination of series and parallel, which is not limited herein.

[0063] Based on Figure 3AThe detection circuit 50 shown, when the input voltage at the control input terminal 31 satisfies the conduction condition of the triode 70 (for example, for an N-type triode, when the voltage corresponding to the control signal input to the base of the N-type triode is greater than the conduction voltage of the N-type triode, the N-type triode conducts. Another example is that for a P-type triode, when the voltage corresponding to the control signal input to the base of the P-type triode is less than the conduction voltage of the P-type triode, the P-type triode conducts), if the PWM signal to be detected is in a normal connection state, and the high level of the PWM signal to be detected is V0 and the low level is V1, the filtering circuit 40 can filter the PWM signal through the resistor unit 110 and the capacitor unit 120, and output a detection result signal with a voltage value between V0 - V1; if the PWM signal to be detected is shorted to ground, the voltage value of the detection result signal output by the filtering circuit 40 is 0; if the PWM signal to be detected is shorted to a power supply with a voltage value of VCC1, the voltage value of the detection result signal output by the filtering circuit 40 is VCC1.

[0064] After receiving the detection result signal, the controller 20 can determine whether the PWM signal to be detected is working properly based on the voltage value of the detection result signal. If the voltage value of the detection result signal received by the controller 20 is between V0 - V1, it indicates that the PWM signal to be detected is in a normal connection state; if the voltage value of the detection result signal received by the controller 20 is 0, it indicates that the PWM signal to be detected is shorted to ground; if the voltage value of the detection result signal received by the controller 20 is VCC1, it indicates that the PWM signal to be detected is shorted to a power supply with a voltage value of VCC1. In addition, when the controller 20 determines that the PWM signal to be detected is abnormal, it can make corresponding processing.

[0065] It should be understood that Figure 3A The schematic diagram of the specific circuit of the detection circuit 50 shown is only an example. In some other embodiments, the control circuit 30 and the filtering circuit 40 can also be replaced by other circuits or circuit modules, which are not limited herein.

[0066] For example, in some embodiments, referring to Figure 3B , compared with Figure 3A the situation shown, the collector of the triode 70 is connected to the output terminal 33 of the control circuit 30 through the diode D1. Among them, the anode of the diode D1 is connected to the collector of the triode 70, and the cathode is connected to the output terminal 33 of the control circuit 30. In this way, it can be avoided that the triode 70 is broken down due to the too high voltage of the PWM signal to be detected.

[0067] Another example is that in some embodiments, the control circuit 30 can also use multiple triodes.

[0068] Exemplarily, Figure 3CShows a schematic diagram of a specific circuit of another detection circuit 50.

[0069] Exemplarily, referring to Figure 3C , compared with the foregoing Figure 3A illustrated embodiment, the control circuit 30 may include a triode 80, a triode 90, and a resistor unit 130.

[0070] Among them, the base of the triode 80 is connected to the control input terminal 31, the emitter of the triode 80 is grounded, the collector of the triode 80 is connected to one end of the resistor unit 130, and the other end of the resistor unit 130 is connected to the base of the triode 90. The collector of the triode 90 is connected to the aforementioned output terminal 33, and the emitter of the triode 90 is connected to the aforementioned power input terminal 32. When the voltage of the control signal input to the base of the triode 80 is greater than the conduction voltage of the triode 80, the triode 80 conducts, and a voltage is input to the base of the triode 90 through the resistor unit 130; when the voltage input to the base of the triode 90 is less than the conduction voltage of the triode 90, the triode 90 conducts, the control circuit 30 is turned on, and a voltage signal is output to the aforementioned one end of the resistor unit 60 to enable the detection of the PWM signal.

[0071] It should be understood that the conduction conditions of the triode 80 and the triode 90 may be different according to the types (N-type or P-type) of the triode 80 and the triode 90, and the conduction conditions of the triode 80 and the triode 90 are not limited herein. For example, for an N-type triode, when the voltage corresponding to the control signal input to the base of the N-type triode is greater than the conduction voltage of the N-type triode, the N-type triode conducts. For another example, for a P-type triode, when the voltage corresponding to the control signal input to the base of the P-type triode is less than the conduction voltage of the P-type triode, the P-type triode conducts.

[0072] In some embodiments, referring to Figure 3D , relative to Figure 3C illustrated embodiment, the collector of the triode 90 is connected to the output terminal 33 through a diode D2. Among them, the anode of the diode D2 is connected to the collector of the triode 90, and the cathode is connected to the output terminal 33 of the control circuit 30. In this way, it is possible to avoid breakdown of the triode 90 due to the excessive voltage of the PWM signal to be detected.

[0073] In some embodiments, referring to Figure 3E , the control circuit 30 may also be implemented by a MOS transistor.

[0074] As Figure 3EAs shown, the control circuit 30 may include a MOS transistor. The gate of the MOS transistor is connected to the control input terminal 31 of the control circuit 30, the drain is connected to the power input terminal 32, and the source is connected to the output terminal 33. When the voltage of the control signal input to the gate of the MOS transistor is greater than the turn-on voltage of the MOS transistor (i.e., when the control signal is valid), the MOS transistor conducts, and outputs a voltage signal to the output terminal 33 (i.e., outputs to the aforementioned one end of the resistance unit 60), the control circuit 30 is turned on, and the detection of the PWM signal is enabled.

[0075] In some embodiments, the aforementioned Figures 3A to 3E shown filter circuit 40 may also adopt other forms.

[0076] For example, referring to Figure 4A In some embodiments, the filter circuit 40 may include a resistance unit 140, a resistance unit 150, a capacitance unit 160, and a capacitance unit 170. One end of the resistance unit 140 is connected to the input terminal 34 of the filter circuit 40, and the other end of the resistance unit 140 is connected to one end of the resistance unit 150 and one end of the capacitance unit 160. The other end of the resistance unit 150 is connected to one end of the capacitance unit 170 and the output terminal 35 of the filter circuit 40, and the other ends of the capacitance unit 160 and the capacitance unit 170 are grounded.

[0077] When the signal input to the input terminal 34 of the filter circuit 40 is a DC signal, the voltage value of the detection result signal output by the filter circuit 40 through the output terminal 35 is the voltage value of the DC signal. When the signal input to the input terminal 34 of the filter circuit 40 is a PWM signal, the voltage value of the detection result signal output by the filter circuit 40 through the output terminal 35 is between the high level and the low level of the PWM signal.

[0078] Also for example, referring to Figure 4B , in some embodiments, the filter circuit 40 may include N (N is an integer greater than 2) filter units (such as filter unit 1, filter unit 2,..., filter unit N), each filter unit includes a resistance unit and a capacitance unit, one end of the resistance unit in each filter unit is connected to one end of the capacitance unit in this filter unit, and the other end of the capacitance unit in this filter unit is grounded. Wherein:

[0079] The other end of the resistor unit in the first filtering unit (e.g., filtering unit 1) among the N filtering units is connected to the input terminal 34 of the filtering circuit 40; the above-mentioned one end of the resistor unit in the i-th filtering unit (e.g., filtering units 2 to N-1) among the N filtering units is further connected to the other end of the resistor unit in the (i + 1)-th filtering unit among the N filtering units, where i is an integer greater than or equal to 1 and less than N; the above-mentioned one end of the resistor unit in the N-th filtering unit (e.g., filtering unit N) among the N filtering units is further connected to the output terminal 35 of the filtering circuit 40.

[0080] When the signal input at the input terminal 34 of the filtering circuit 40 is a DC signal, the voltage value of the detection result signal output by the filtering circuit 40 through the output terminal 35 is the voltage value of this DC signal. When the signal input at the input terminal 34 of the filtering circuit 40 is a PWM signal, the voltage value of the detection result signal output by the filtering circuit 40 through the output terminal 35 is between the high level and the low level of this PWM signal.

[0081] It should be understood that in some embodiments, the above-mentioned detection circuit being arranged outside the detection device 10 is only an example. In some other embodiments, the detection circuit can also be arranged inside the corresponding detection device 10. The embodiments of the present application do not limit the installation position of the detection circuit 50.

[0082] Although the present utility model has been disclosed above with preferred embodiments, the present utility model is not limited thereto. Any person skilled in the art, without departing from the spirit and scope of the present utility model, makes various changes and modifications, which should all be included within the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the scope defined by the claims.

Claims

1. A detection circuit, characterized in that: It includes a control circuit, a resistor unit and a filter circuit, wherein the output end of the control circuit is connected to one end of the resistor unit, and the other end of the resistor unit is connected to the input end of the filter circuit; The control circuit outputs a voltage signal to the one end of the resistance unit when the control signal received at the input end of the control circuit is valid; When the input end of the filter circuit receives the first signal to be detected, the filter circuit outputs a detection result signal corresponding to the first signal through the output end of the filter circuit; in: Corresponding to the first signal being a PWM wave signal, the voltage value of the detection result signal is a voltage value between a high level and a low level of the PWM wave signal; Corresponding to the first signal being grounded, the voltage value of the detection result signal is 0; Corresponding to the first signal being connected to a DC voltage signal, a voltage value of the detection result signal is a voltage value of the DC voltage signal, wherein the voltage value of the DC voltage signal is higher than a high level of the PWM wave signal.

2. The detection circuit according to claim 1, characterized in that: The control circuit includes a first transistor, the emitter of the first transistor is connected to a power supply, the base of the first transistor is connected to an input end of the control circuit, and the collector of the first transistor is connected to an output end of the control circuit.

3. The detection circuit according to claim 2, characterized in that: The control circuit also includes a first diode, and the collector of the first transistor is connected to the output end of the control circuit through the first diode, wherein the anode of the first diode is connected to the collector of the first transistor, and the cathode of the first diode is connected to the output end of the control circuit.

4. The detection circuit according to claim 1, characterized in that: The control circuit includes a second triode, a third triode and a first resistor unit; wherein, The emitter of the second transistor is grounded, the base of the second transistor is connected to the input end of the control circuit, and the collector of the second transistor is connected to one end of the first resistance unit; The other end of the first resistance unit is connected to the base of the third transistor; The emitter of the third transistor is connected to the power supply, and the collector of the third transistor is connected to the output end of the control circuit.

5. The detection circuit according to claim 4, characterized in that: The control circuit also includes a second diode, and the collector of the third transistor is connected to the output end of the control circuit through the second diode, wherein the anode of the second diode is connected to the collector of the third transistor, and the cathode of the second diode is connected to the output end of the control circuit.

6. The detection circuit according to claim 1, characterized in that: The control circuit comprises a field effect transistor, a gate of the field effect transistor is connected to an input end of the control circuit, a drain of the field effect transistor is connected to a power supply, and a source of the field effect transistor is connected to an output end of the control circuit.

7. The detection circuit according to any one of claims 1 to 6, characterized in that: The filter circuit comprises a second resistor unit and a first capacitor unit; wherein: One end of the second resistance unit is connected to the input end of the filter circuit, the other end of the second resistance unit is connected to one end of the first capacitance unit and the output end of the filter circuit, and the other end of the first capacitance unit is grounded.

8. The detection circuit according to any one of claims 1 to 6, characterized in that: The filter circuit comprises a third resistor unit and a second capacitor unit, a fourth resistor unit and a third capacitor unit; wherein: One end of the third resistance unit is connected to the input end of the filter circuit, the other end of the third resistance unit is connected to one end of the second capacitor unit and one end of the fourth resistance unit, the other end of the fourth resistance unit is connected to one end of the third capacitor unit and the output end of the filter circuit, and the other end of the second capacitor unit and the other end of the third capacitor unit are grounded.

9. The detection circuit according to any one of claims 1 to 6, characterized in that: The filtering circuit comprises N filtering units, each of which comprises a resistor unit and a capacitor unit, one end of the resistor unit in each filtering unit is connected to one end of the capacitor unit, and the other end of the capacitor unit is grounded, and N is an integer greater than 2; in: The other end of the resistor unit in the first filter unit among the N filter units is connected to the input end of the filter circuit; The one end of the resistor unit in the i-th filter unit among the N filter units is also connected to the other end of the resistor unit in the i+1-th filter unit among the N filter units, where i is an integer greater than or equal to 1 and less than N; The one end of the one resistor unit in the Nth filter unit among the N filter units is also connected to the output end of the filter circuit.

10. The detection circuit according to claim 1, characterized in that: The detection circuit also includes a controller, which is connected to the output end of the filter circuit; The controller determines that the first signal is normal when the voltage value of the detection result signal received from the output end of the filter circuit is between the high level and the low level of the PWM wave signal; The controller determines that the first signal is abnormal when the voltage value of the detection result signal received from the output end of the filter circuit is greater than the high level of the PWM wave signal or is 0.

11. An electronic device, characterized in that: The invention comprises the detection circuit according to any one of claims 1 to 10.

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