Anti-pinch detection circuit and motor device

Abstract

The utility model relates to an anti-pinch detection circuit and a motor device, the anti-pinch detection circuit comprises a sampling circuit, a differential amplification circuit, a ripple signal conversion circuit, a low pass filter circuit and a controller, the sampling circuit samples a ripple current signal of a vehicle window motor to obtain a corresponding voltage sampling signal, and the voltage sampling signal is sent to the differential amplification circuit; the differential amplification circuit carries out differential amplification on the voltage sampling signal to obtain a voltage amplification signal, the voltage amplification signal is divided into two paths, one path is converted into square wave signals through the ripple signal conversion circuit, the controller determines the position of a car window according to the number of the square wave signals, and the other path is subjected to low-pass filtering through the low-pass filtering circuit to obtain the voltage amplification signal. If the position of the car window is located in the preset anti-pinch area, the controller determines whether the car window is locked or blocked or not according to the amplitude of the low-frequency ripple signal. The anti-pinch detection circuit adopts two-path detection, so that the influence of environment or other factors on the ripple current signal is avoided, further anti-pinch misjudgment is avoided, and the anti-pinch detection accuracy is improved.

Description

Technical Field

[0001] The utility model relates to the field of electric windows, in particular to an anti-pinch detection circuit and a motor device. Background Art

[0002] With the development of electronic technology, electric windows have gradually become one of the basic configurations of cars. Electric windows need to have an anti-pinch function, which means that the electric windows can perform anti-pinch detection during the automatic rise process. When an obstacle is detected, the window is controlled to reverse a certain distance to release the obstacle, thereby realizing the anti-pinch function and ensuring the safety of passengers.

[0003] The current anti-pinch detection scheme determines whether the window encounters an obstacle by the periodic changes in the ripple current of the window motor. However, when the window is affected by the external environment, such as aging of the barrier strip or other external factors, the periodic changes in the ripple current may also occur, resulting in misjudgment of anti-pinch detection and low detection accuracy. Utility Model Content

[0004] The embodiment of the utility model aims to provide an anti-pinch detection circuit and a motor device, which can perform accurate anti-pinch detection on a vehicle window.

[0005] In order to solve the above technical problems, the present utility model provides the following technical solutions:

[0006] In a first aspect, an embodiment of the utility model provides an anti-pinch detection circuit, the anti-pinch detection circuit comprising: a sampling circuit, a differential amplifier circuit, a ripple signal conversion circuit, a low-pass filter circuit and a controller;

[0007] The sampling circuit is connected in series to the working circuit of the window motor, and is used to sample the ripple current signal of the window motor and obtain a corresponding voltage sampling signal;

[0008] The differential amplifier circuit is connected to the sampling circuit, the ripple signal conversion circuit and the low-pass filter circuit respectively, and the differential amplifier circuit is used to perform differential amplification on the voltage sampling signal to obtain a voltage amplification signal;

[0009] The ripple signal conversion circuit is also connected to the first input terminal of the controller, and the low-pass filter circuit is also connected to the second input terminal of the controller;

[0010] The ripple signal conversion circuit is used to convert the voltage amplification signal into a square wave signal, the low-pass filtering circuit is used to perform low-pass filtering on the voltage amplification signal to obtain a low-frequency ripple signal, and the controller is used to determine the position of the vehicle window according to the number of the square wave signals. If the position of the vehicle window is in a preset anti-pinch area, the controller is also used to determine whether the vehicle window is blocked or obstructed according to the amplitude of the low-frequency ripple signal.

[0011] In some embodiments, the ripple signal conversion circuit includes a first comparison module;

[0012] The first input end of the first comparison module is connected to the differential amplifier circuit, the second input end of the first comparison module is used to access a first reference voltage, and the first comparison module is used to compare the voltage amplification signal with the first reference voltage to obtain the square wave signal.

[0013] In some embodiments, the first comparison module includes a voltage dividing unit and a first comparator;

[0014] A first end of the voltage dividing unit is connected to a first power supply, a second end of the voltage dividing unit is connected to a non-inverting input end of the first comparator, a third end of the voltage dividing unit is grounded, and the voltage dividing unit is used to divide the first power supply to obtain the first reference voltage;

[0015] The inverting input terminal of the first comparator is connected to the differential amplifier circuit, and the output terminal of the first comparator is connected to the first input terminal of the controller.

[0016] In some embodiments, the voltage divider unit includes: a first resistor and a second resistor, the first resistor and the second resistor are connected in series between the first power supply and ground, and a common connection point of the first resistor and the second resistor is connected to the in-phase input terminal of the first comparator.

[0017] In some embodiments, the ripple signal conversion circuit further includes a first filtering module and a first amplifying module;

[0018] The first filtering module is connected to the differential amplifier circuit and the input end of the first amplifier module respectively, and the output end of the first amplifier module is connected to the first input end of the first comparison module;

[0019] The first filtering module is used to filter out a direct current signal in the voltage amplified signal, and the first amplifying module is used to amplify the filtered voltage amplified signal.

[0020] In some embodiments, the first filtering module includes a first capacitor, and the first amplifying module includes a first amplifier, a third resistor, a fourth resistor, and a second capacitor;

[0021] One end of the first capacitor is connected to the differential amplifier circuit, the other end of the first capacitor is connected to the non-inverting input terminal of the first amplifier, the output terminal of the first amplifier is connected to the first input terminal of the first comparison module, the third resistor and the second capacitor are respectively connected in series between the inverting input terminal and the output terminal of the first amplifier, and the fourth resistor is connected in series between the inverting input terminal of the first amplifier and the ground.

[0022] In some embodiments, the ripple signal conversion circuit further includes a second comparison module;

[0023] The first input end of the second comparison module is used to access the voltage amplification signal, the second input end of the second comparison module is used to access the second reference voltage, the output end of the second comparison module is connected to the third input end of the controller, and the second comparison module is used to compare the voltage amplification signal with the second reference voltage and output a comparison signal so that the controller determines whether the window motor is overcurrent based on the comparison signal.

[0024] In some embodiments, the differential-differential amplifier circuit includes a second filtering module, a third filtering module, and a second amplification module;

[0025] The second filtering module is connected in series between the first input terminal and the second input terminal of the second amplifying module, and the second filtering module is used to filter out common mode interference in the voltage sampling signal;

[0026] The input end of the second amplifying module is used to access the voltage sampling signal, the output end of the second amplifying module is connected to the ripple signal conversion circuit and the low-pass filtering circuit respectively, and the second amplifying module is used to perform differential amplification on the filtered voltage sampling signal to obtain the voltage amplified signal;

[0027] The third filtering module is connected in series between the first power supply and the power supply end of the second amplifying module, and the third filtering module is used to filter out high-frequency signals in the first power supply.

[0028] In some embodiments, the second filtering module includes a third capacitor and a fourth capacitor, the third filtering module includes a fifth capacitor, a sixth capacitor and a magnetic bead, the second amplification module includes a second amplifier, a fifth resistor, a sixth resistor, a seventh resistor and a seventh capacitor, and the sampling circuit includes a sampling resistor;

[0029] One end of the sampling resistor is connected to one end of the fifth resistor and one end of the third capacitor respectively, and the other end of the sampling resistor, one end of the third capacitor and one end of the sixth resistor are grounded together;

[0030] The other end of the fifth resistor is respectively connected to one end of the fourth capacitor and the non-inverting input end of the second amplifier, the other end of the fourth capacitor is respectively connected to the other end of the sixth resistor and the inverting input end of the second amplifier, the seventh resistor and the seventh capacitor are respectively connected in series between the inverting input end and the output end of the second amplifier, and the output end of the second amplifier is also respectively connected to the ripple signal conversion circuit and the low-pass filter circuit;

[0031] The fifth capacitor and the sixth capacitor are respectively connected in series between the power supply terminal of the second amplifier and the ground, and the magnetic bead is connected in series between the first power supply and the power supply terminal of the second amplifier.

[0032] In a second aspect, an embodiment of the present invention provides a motor device, which includes a vehicle window motor and the anti-pinch detection circuit as described above.

[0033] In various embodiments of the utility model, the anti-pinch detection circuit includes a sampling circuit, a differential amplifier circuit, a ripple signal conversion circuit, a low-pass filter circuit and a controller, wherein the sampling circuit is used to sample the ripple current signal of the window motor and obtain a corresponding voltage sampling signal, and the differential amplifier circuit then differentially amplifies the voltage sampling signal to obtain a voltage amplification signal. The voltage amplification signal is divided into two paths, one of which is converted into a square wave signal by a ripple signal conversion circuit so that the controller determines the position of the window according to the number of square wave signals and determines whether the position of the window is in a preset anti-pinch area, and the other is low-pass filtered by a low-pass filter circuit to obtain a low-frequency ripple signal. If the position of the window is in the preset anti-pinch area, the controller determines whether the window is blocked or obstructed according to the amplitude of the low-frequency ripple signal.

[0034] Therefore, compared with the solution of detecting whether the window encounters an obstacle only by the number of ripples in the ripple current signal, the anti-pinch detection circuit not only detects the position of the window through the ripple signal conversion circuit and the controller, but also detects the amplitude of the voltage sampling signal through the low-pass filter circuit and the controller after determining that the window is in the anti-pinch area, so as to determine whether the window is blocked or encounters resistance, thereby realizing the anti-pinch function. The anti-pinch detection circuit adopts two-way detection to avoid the influence of the environment or other factors on the ripple current signal, thereby avoiding misjudgment of anti-pinch and improving the accuracy of anti-pinch detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0036] Figure 1 It is a structural schematic diagram of a motor device provided by an embodiment of the utility model;

[0037] Figure 2 It is a structural schematic diagram of an anti-pinch detection circuit provided by an embodiment of the utility model;

[0038] Figure 3 It is a circuit structure schematic diagram of a differential amplifier circuit provided by an embodiment of the utility model;

[0039] Figure 4 It is a circuit structure diagram of a first filtering module and a first amplifying module provided by an embodiment of the utility model;

[0040] Figure 5 It is a circuit structure diagram of a first comparison module provided in an embodiment of the utility model;

[0041] Figure 6 It is a circuit structure schematic diagram of a low-pass filter circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0043] See also Figure 1 , Figure 1 is a schematic diagram of the structure of a motor device provided by an embodiment of the utility model, such as Figure 1 As shown, the motor device includes a window motor M and an anti-pinch detection circuit 100, wherein the anti-pinch detection circuit 100 is used to detect the ripple current of the window motor M, and determine the window position and whether the window is blocked or blocked (encountered an obstacle) by processing and analyzing the ripple current.

[0044] Generally, the position of the window motor M is detected by detecting the number of ripple currents. Moreover, when the window encounters an obstacle, the ripple period of the ripple current will become significantly larger when it intersects with the window rising steadily. Based on this feature, it is possible to determine whether the window encounters an obstacle by detecting the periodic change of the ripple current, so as to take anti-pinch measures.

[0045] However, when the car window is affected by the external environment or other factors, the cycle of the ripple current may also change, resulting in misjudgment of anti-pinch and low detection accuracy.

[0046] Therefore, the present invention provides an anti-pinch detection circuit 100, such as Figure 1As shown, the anti-pinch detection circuit 100 includes a sampling circuit 10, a differential amplifier circuit 20, a ripple signal conversion circuit 30, a low-pass filter circuit 40 and a controller 50. The sampling circuit 10 is connected in series to the working loop of the window motor M, the differential amplifier circuit 20 is connected to the sampling circuit 10, the ripple signal conversion circuit 30 and the low-pass filter circuit 40 respectively, the ripple signal conversion circuit 30 is also connected to the first input end of the controller 50, and the low-pass filter circuit 40 is also connected to the second input end of the controller 50.

[0047] The sampling circuit 10 samples the ripple current signal of the window motor M and obtains a corresponding voltage sampling signal. The differential amplifier circuit 20 then differentially amplifies the voltage sampling signal to obtain a voltage amplified signal. The voltage amplified signal is divided into two paths. One path passes through the ripple signal conversion circuit 30. The ripple signal conversion circuit 30 converts the voltage amplified signal into a square wave signal, so that the controller 50 determines the position of the window according to the number of square wave signals and determines whether the position of the window is in a preset anti-pinch area. The other path passes through the low-pass filter circuit 40. The low-pass filter circuit 40 performs low-pass filtering on the voltage amplified signal to obtain a low-frequency ripple signal. If the position of the window is in the preset anti-pinch area, the controller 50 determines whether the window is blocked or obstructed according to the amplitude of the low-frequency ripple signal.

[0048] The controller 50 obtains the number of square wave signals and determines the position of the vehicle window according to the number of square wave signals. The number of square waves corresponds to the position of the vehicle window and can be obtained by looking up a table. The anti-pinch area is 4mm-200mm from the top of the vehicle window. The condition for the anti-pinch mechanism to be activated is that the position of the vehicle window needs to be within the anti-pinch area.

[0049] If it is determined that the position of the vehicle window is in the anti-pinch area, the controller 50 also detects the amplitude of the low-frequency ripple signal. If the amplitude of the low-frequency ripple signal is greater than the first preset threshold, it is determined that the vehicle window is blocked. If the amplitude of the low-frequency ripple signal is less than or equal to the first preset threshold and greater than the second preset threshold, it is determined that the vehicle window is obstructed, wherein the first preset threshold is greater than the second preset threshold.

[0050] If the controller 50 determines that the window is in the anti-pinch area and the window is not blocked or obstructed, the window motor M is controlled to work normally. If the controller 50 determines that the window is in the anti-pinch area and the window is blocked or obstructed, the window motor M is controlled to reverse and the window is lowered a certain distance to release the obstacle, thereby realizing the anti-pinch function and ensuring the safety of the passengers.

[0051] The controller 50 may also be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single chip microcomputer, an ARM (Acorn RICS Machine) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component or any combination of these components. In addition, the controller 50 may also be any conventional processor, controller, microcontroller or state machine. The controller 50 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP and / or any other such configuration.

[0052] In summary, compared with the solution of detecting whether the window encounters an obstacle only by the number of ripples in the ripple current signal, the anti-pinch detection circuit not only detects the position of the window through the ripple signal conversion circuit and the controller, but also detects the amplitude of the voltage sampling signal through the low-pass filter circuit and the controller after determining that the window is in the anti-pinch area, so as to determine whether the window is blocked or encounters resistance, thereby realizing the anti-pinch function. The anti-pinch detection circuit adopts two-way detection to avoid the influence of the environment or other factors on the ripple current signal, thereby avoiding misjudgment of anti-pinch and improving the accuracy of anti-pinch detection.

[0053] See also Figure 2 , Figure 2 : is a schematic diagram of a structure of an anti-pinch detection circuit provided by an embodiment of the utility model, such as Figure 2 As shown, the ripple signal conversion circuit 30 includes a first comparison module 301, wherein a first input end of the first comparison module 301 is connected to the differential amplifier circuit 20, and a second input end of the first comparison module 301 is used to access a first reference voltage. The first comparison module 301 compares the voltage amplification signal with the first reference voltage to obtain a square wave signal.

[0054] If the amplitude of the voltage-amplified signal is greater than the first reference voltage, the first comparison module 301 outputs a low-level signal; if the amplitude of the voltage-amplified signal is less than or equal to the first reference voltage, the first comparison module 301 outputs a high-level signal. Therefore, the first comparison module 301 outputs a square wave signal, and the number of square wave signals is the number of ripples of the voltage-amplified signal.

[0055] Furthermore, since the DC component of the ripple current generated when the window rises instantaneously is relatively large, the amplitude of the voltage amplification signal is relatively large, and the first comparison module 301 will always output a high-level signal, causing the first comparison module 301 to be unable to collect the ripple during the instantaneous rise of the window, thereby causing the controller 50 to detect the position of the window inaccurately.

[0056] Therefore, in order to improve the accuracy of the window position detection, it is necessary to filter out the DC component in the voltage amplification signal. Figure 2 As shown, the ripple signal conversion circuit 30 also includes a first filtering module 302 and a first amplifying module 303, wherein the first filtering module 302 is respectively connected to the differential amplifier circuit 20 and the input end of the first amplifying module 303, and the output end of the first amplifying module 303 is connected to the first input end of the first comparing module 301.

[0057] The first filtering module 302 is a DC filtering module, which is used to filter the DC signal in the voltage amplified signal. The filtered voltage amplified signal will be weakened, so it needs to be further amplified. The first amplifying module 303 is used to amplify the filtered voltage amplified signal, and then enters the first comparing module 301 to obtain a square wave signal.

[0058] In some embodiments, the ripple signal conversion circuit 30 further includes a second comparison module 304 , wherein a first input terminal of the second comparison module 304 is used to access the voltage amplification signal, and a second input terminal of the second comparison module 304 is used to access a second reference voltage.

[0059] The second comparison module 304 compares the voltage amplification signal with the second reference voltage and outputs a comparison signal, so that the controller 50 determines whether the window motor M is overcurrent according to the comparison signal. If the amplitude of the voltage amplification signal is greater than the second reference voltage, the second comparison module 304 outputs a high-level comparison signal. When the controller 50 receives the high-level comparison signal, it determines that the window motor M is overcurrent. The controller 50 then controls the window motor M to stop, or reduces the driving power of the motor, etc., to reduce the working current of the window motor M and achieve overcurrent protection.

[0060] In some embodiments, Figure 2 As shown, the differential amplifier circuit 20 includes a second filter module 201, a third filter module 202 and a second amplifier module 203, wherein the second filter module 201 is connected in series between the first input terminal and the second input terminal of the second amplifier module 203, the input terminal of the second amplifier module 203 is used to access the voltage sampling signal, the output terminal of the second amplifier module 203 is respectively connected to the ripple signal conversion circuit 30 and the low-pass filter circuit 40, and the third filter module 202 is connected in series between the first power supply and the power supply terminal of the second amplifier module 203.

[0061] The second filtering module 201 filters out the common mode interference in the voltage sampling signal to reduce the clutter. The second amplifying module 203 performs differential amplification on the filtered voltage sampling signal to obtain a voltage amplified signal to achieve the amplification function. The third filtering module 202 filters out the high frequency signal in the first power supply, and the first power supply after filtering out the high frequency signal supplies power to the second amplifying module 203.

[0062] See also Figure 3 , Figure 3 is a circuit structure diagram of a differential amplifier circuit provided by an embodiment of the utility model, such as Figure 3 As shown, the second filtering module 201 includes a third capacitor C20 and a fourth capacitor C21, the third filtering module 202 includes a fifth capacitor C1, a sixth capacitor C2 and a magnetic bead FB1, the second amplifying module 203 includes a second amplifier U1A, a fifth resistor R5, a sixth resistor R10, a seventh resistor R12 and a seventh capacitor C5, and the sampling circuit 10 includes a sampling resistor R7.

[0063] One end of the sampling resistor R7 is connected to one end of the fifth resistor R5 and one end of the third capacitor C20 respectively, and the other end of the sampling resistor R7, one end of the third capacitor C20 and one end of the sixth resistor R10 are grounded together.

[0064] The other end of the fifth resistor R5 is respectively connected to one end of the fourth capacitor C21 and the non-inverting input terminal of the second amplifier U1A, the other end of the fourth capacitor C21 is respectively connected to the other end of the sixth resistor R10 and the inverting input terminal of the second amplifier U1A, the seventh resistor R12 and the seventh capacitor C5 are respectively connected in series between the inverting input terminal and the output terminal of the second amplifier U1A, and the output terminal of the second amplifier U1A is also respectively connected to the ripple signal conversion circuit 30 and the low-pass filter circuit 40.

[0065] The fifth capacitor C1 and the sixth capacitor C2 are respectively connected in series between the power supply terminal of the second amplifier U1A and the ground, and the magnetic bead FB1 is connected in series between the first power supply and the power supply terminal of the second amplifier U1A.

[0066] The third capacitor C20 is used to filter the high-frequency components in the voltage sampling signal, the fourth capacitor C21 is used to filter out common-mode interference, the sixth resistor R10 and the seventh resistor R12 are used to determine the amplification gain of the second amplifier U1A, the seventh capacitor C5 is used to adjust the phase of the second amplifier U1A, and the seventh resistor R12 and the seventh capacitor C5 also have a filtering function.

[0067] The fifth capacitor C1, the sixth capacitor C2 and the magnetic bead FB1 are used to filter out high frequency components in the first power supply VDD, and the filtered first power supply VDD then supplies power to the second amplifier U1A. In this embodiment, the voltage of the first power supply VDD is 5V.

[0068] The sampling resistor R7 samples the ripple current signal of the window motor M to obtain a corresponding voltage sampling signal. The second amplifier U1A differentially amplifies the voltage sampling signal to obtain a voltage amplification signal. The voltage amplification signal is output through the output end of the second amplifier U1A, one path is converted into a square wave signal through the ripple signal conversion circuit 30, and the other path is filtered through the low-pass filter circuit 40 to obtain a low-frequency ripple signal.

[0069] See also Figure 4 , Figure 4 is a schematic diagram of a circuit structure of a first filtering module and a first amplifying module provided by an embodiment of the utility model, such as Figure 4 As shown, the first filtering module 302 includes a first capacitor C4, and the first amplifying module 303 includes a first amplifier U1 B, a third resistor R11, a fourth resistor R13 and a second capacitor C13. Among them, one end of the first capacitor C4 is connected to the differential amplifier circuit 20, the other end of the first capacitor C4 is connected to the non-inverting input end of the first amplifier U1 B, the output end of the first amplifier U1 B is connected to the first input end of the first comparison module 301, the third resistor R11 and the second capacitor C13 are respectively connected in series between the inverting input end and the output end of the first amplifier U1 B, and the fourth resistor R13 is connected in series between the inverting input end and the ground of the first amplifier U1 B.

[0070] The first capacitor C4 is a coupling capacitor. The first capacitor C4 filters out the DC component in the voltage amplified signal. The filtered voltage amplified signal is transmitted to the non-inverting input terminal of the first amplifier U1 B. The first amplifier U1 B is a non-inverting amplifier, and its gain is determined by the ratio of the third resistor R11 and the fourth resistor R13.

[0071] See also Figure 5 , Figure 5 is a schematic diagram of a circuit structure of a first comparison module provided by an embodiment of the utility model, such as Figure 5As shown, the first comparison module 301 includes a voltage divider unit 3011 and a first comparator U3, wherein a first end of the voltage divider unit 3011 is connected to a first power supply VDD, a second end of the voltage divider unit 3011 is connected to a non-inverting input end of the first comparator U3, and a third end of the voltage divider unit 3011 is grounded. Specifically, the voltage divider unit 3011 includes a first resistor R18 and a second resistor R19, the first resistor R18 and the second resistor R19 are connected in series between the first power supply VDD and ground, and a common connection point of the first resistor R18 and the second resistor R19 is connected to the non-inverting input end of the first comparator U3.

[0072] An inverting input terminal of the first comparator U3 is connected to the differential amplifier circuit 20 , and an output terminal of the first comparator U3 is connected to a first input terminal of the controller 50 .

[0073] The first resistor R18 and the second resistor R19 divide the voltage of the first power supply VDD to obtain a voltage division signal, and the voltage of the voltage division signal is a first reference voltage. The value of the first reference voltage can be set as needed, and in this embodiment, it is 1.08V.

[0074] In some embodiments, a filter capacitor may be provided between the non-inverting input terminal of the first comparator U3 and the ground, and the filter capacitor may filter out noise in the first power supply VDD.

[0075] In some embodiments, a filter capacitor and a filter resistor connected in series may be provided between the output terminal of the first comparator U3 and the ground to form an RC filter module to filter the square wave signal.

[0076] The first comparator U3 has an open-circuit output, and a pull-up resistor is provided at its output terminal, and the pull-up resistor is also connected to the first power supply VDD.

[0077] In this embodiment, the model of the first comparator U3 is LM2903YDT, the first reference voltage can be transmitted to pin 3 of the first comparator U3, the voltage amplification signal is transmitted to pin 2 of the first comparator U3, and pin 1 of the first comparator U3 is connected to the first input terminal of the controller 50.

[0078] The first comparator U3 compares the voltage amplification signal with the first reference voltage and outputs a corresponding square wave signal through its pin 1. The square wave signal is transmitted to the first input terminal of the controller 50 for ripple counting.

[0079] The controller 50 determines the position of the vehicle window according to the number of square wave signals, and determines whether it is in a preset anti-pinch area.

[0080] In some embodiments, please refer to Figure 5The second comparison module 304 can be implemented by the first comparator U3. Specifically, the other in-phase input terminal of the first comparator U3, i.e., the 5th pin thereof, is used to access the second reference voltage, the inverting input terminal of the first comparator U3, i.e., the 6th pin thereof, is used to access the voltage amplification signal, and the other output terminal of the first comparator U3, i.e., the 7th pin thereof, is connected to the third input terminal of the controller 50.

[0081] The first comparator U3 compares the voltage amplification signal with the second reference voltage and outputs a corresponding comparison signal, which is transmitted to the third input terminal of the controller 50, so that the controller 50 determines whether the window motor M is overcurrent according to the comparison signal.

[0082] If the voltage of the voltage-amplified signal is greater than the second reference voltage, the first comparator U3 outputs a high-level comparison signal. When the controller 50 receives the high-level comparison signal, it determines that the window motor M is overcurrent, and then takes control measures to control the window motor M to stop or reduce the power of the window motor M to reduce the current of the window motor M, thereby realizing overcurrent protection for the window motor M.

[0083] See also Figure 6 , Figure 6 Schematic diagram of the circuit structure of a low-pass filter circuit provided by an embodiment of the utility model, such as Figure 6 As shown, the low-pass filter circuit 40 includes a first low-pass filter module 401, a second low-pass filter module 402, a voltage divider module 403, a voltage follower U2 and an ESD tube D1.

[0084] Among them, the first low-pass filter module 401 includes a resistor R15 and a capacitor C8, and the second low-pass filter module 402 includes a resistor R16 and a capacitor C9. One end of the resistor R15 is used to access the voltage amplification signal, and the other end of the resistor R15 is respectively connected to one end of the resistor R16 and one end of the capacitor C8, and the other end of the resistor R16 is respectively connected to one end of the capacitor C9 and the in-phase input end of the voltage follower U2, and the other end of the capacitor C8 and the other end of the capacitor C9 are both grounded.

[0085] The first low-pass filter module 401 and the second low-pass filter module 402 are both used to filter the voltage amplification signal to obtain a low-frequency ripple signal.

[0086] The inverting input terminal of the voltage follower U2 is connected to its output terminal, and the voltage follower U2 transmits the low-frequency ripple signal to its output terminal for output.

[0087] The voltage divider module 403 includes a resistor R23 and a resistor R24, which are connected in series between the output end of the voltage follower U2 and the ground, and the common connection point of the resistor R23 and the resistor R24 ​​is respectively connected to the ESD tube D1 and the second input end of the controller 50, and the ESD tube D1 is used for anti-static.

[0088] The resistor R23 and the resistor R24 ​​divide the low-frequency ripple signal, and the obtained divided voltage signal is transmitted to the second input terminal of the controller 50 to perform overvoltage protection on the second input terminal of the controller 50 .

[0089] After receiving the divided voltage signal, the second input terminal of the controller 50 makes a judgment based on the amplitude and the corresponding threshold value to determine whether the vehicle window is blocked or encounters resistance.

[0090] In summary, the anti-pinch detection circuit not only detects the position of the window through the ripple signal conversion circuit and the controller, but also detects the amplitude of the voltage sampling signal through the low-pass filter circuit and the controller after determining that the window is in the anti-pinch area to determine whether the window is blocked or blocked, thereby realizing the anti-pinch function. The anti-pinch detection circuit adopts two-way detection to avoid the influence of the environment or other factors on the ripple current signal, thereby avoiding misjudgment of anti-pinch and improving the accuracy of anti-pinch detection.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the idea of ​​the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An anti-pinch detection circuit, characterized in that: The anti-pinch detection circuit includes: a sampling circuit, a differential amplifier circuit, a ripple signal conversion circuit, a low-pass filter circuit and a controller; The sampling circuit is connected in series to the working circuit of the window motor, and is used to sample the ripple current signal of the window motor and obtain a corresponding voltage sampling signal; The differential amplifier circuit is connected to the sampling circuit, the ripple signal conversion circuit and the low-pass filter circuit respectively, and the differential amplifier circuit is used to perform differential amplification on the voltage sampling signal to obtain a voltage amplification signal; The ripple signal conversion circuit is also connected to the first input terminal of the controller, and the low-pass filter circuit is also connected to the second input terminal of the controller; The ripple signal conversion circuit is used to convert the voltage amplification signal into a square wave signal, the low-pass filtering circuit is used to perform low-pass filtering on the voltage amplification signal to obtain a low-frequency ripple signal, and the controller is used to determine the position of the vehicle window according to the number of the square wave signals. If the position of the vehicle window is in a preset anti-pinch area, the controller is also used to determine whether the vehicle window is blocked or obstructed according to the amplitude of the low-frequency ripple signal.

2. The anti-pinch detection circuit according to claim 1, characterized in that: The ripple signal conversion circuit includes a first comparison module; The first input end of the first comparison module is connected to the differential amplifier circuit, the second input end of the first comparison module is used to access a first reference voltage, and the first comparison module is used to compare the voltage amplification signal with the first reference voltage to obtain the square wave signal.

3. The anti-pinch detection circuit according to claim 2, characterized in that: The first comparison module includes a voltage dividing unit and a first comparator; A first end of the voltage dividing unit is connected to a first power supply, a second end of the voltage dividing unit is connected to a non-inverting input end of the first comparator, a third end of the voltage dividing unit is grounded, and the voltage dividing unit is used to divide the first power supply to obtain the first reference voltage; The inverting input terminal of the first comparator is connected to the differential amplifier circuit, and the output terminal of the first comparator is connected to the first input terminal of the controller.

4. The anti-pinch detection circuit according to claim 3, characterized in that: The voltage dividing unit includes: a first resistor and a second resistor, the first resistor and the second resistor are connected in series between the first power supply and ground, and a common connection point of the first resistor and the second resistor is connected to the non-inverting input terminal of the first comparator.

5. The anti-pinch detection circuit according to claim 2, characterized in that: The ripple signal conversion circuit also includes a first filtering module and a first amplifying module; The first filtering module is connected to the differential amplifier circuit and the input end of the first amplifier module respectively, and the output end of the first amplifier module is connected to the first input end of the first comparison module; The first filtering module is used to filter out a direct current signal in the voltage amplification signal, and the first amplification module is used to amplify the filtered direct current signal in the voltage amplification signal.

6. The anti-pinch detection circuit according to claim 5, characterized in that: The first filtering module includes a first capacitor, and the first amplifying module includes a first amplifier, a third resistor, a fourth resistor and a second capacitor; One end of the first capacitor is connected to the differential amplifier circuit, the other end of the first capacitor is connected to the non-inverting input terminal of the first amplifier, the output terminal of the first amplifier is connected to the first input terminal of the first comparison module, the third resistor and the second capacitor are respectively connected in series between the inverting input terminal and the output terminal of the first amplifier, and the fourth resistor is connected in series between the inverting input terminal of the first amplifier and the ground.

7. The anti-pinch detection circuit according to claim 5, characterized in that: The ripple signal conversion circuit also includes a second comparison module; The first input end of the second comparison module is used to access the voltage amplification signal, the second input end of the second comparison module is used to access the second reference voltage, the output end of the second comparison module is connected to the third input end of the controller, and the second comparison module is used to compare the voltage amplification signal with the second reference voltage and output a comparison signal so that the controller determines whether the window motor is overcurrent based on the comparison signal.

8. The anti-pinch detection circuit according to claim 1, characterized in that: The differential amplifier circuit includes a second filtering module, a third filtering module and a second amplifying module; The second filtering module is connected in series between the first input terminal and the second input terminal of the second amplifying module, and the second filtering module is used to filter out common mode interference in the voltage sampling signal; The input end of the second amplifying module is used to access the voltage sampling signal, the output end of the second amplifying module is connected to the ripple signal conversion circuit and the low-pass filtering circuit respectively, and the second amplifying module is used to perform differential amplification on the filtered voltage sampling signal to obtain the voltage amplified signal; The third filtering module is connected in series between the first power supply and the power supply end of the second amplifying module, and the third filtering module is used to filter out high-frequency signals in the first power supply.

9. The anti-pinch detection circuit according to claim 8, characterized in that: The second filtering module includes a third capacitor and a fourth capacitor, the third filtering module includes a fifth capacitor, a sixth capacitor and a magnetic bead, the second amplifying module includes a second amplifier, a fifth resistor, a sixth resistor, a seventh resistor and a seventh capacitor, and the sampling circuit includes a sampling resistor; One end of the sampling resistor is respectively connected to one end of the fifth resistor and one end of the third capacitor, and the other end of the sampling resistor, one end of the third capacitor and one end of the sixth resistor are grounded together; The other end of the fifth resistor is respectively connected to one end of the fourth capacitor and the non-inverting input end of the second amplifier, the other end of the fourth capacitor is respectively connected to the other end of the sixth resistor and the inverting input end of the second amplifier, the seventh resistor and the seventh capacitor are respectively connected in series between the inverting input end and the output end of the second amplifier, and the output end of the second amplifier is also respectively connected to the ripple signal conversion circuit and the low-pass filter circuit; The fifth capacitor and the sixth capacitor are respectively connected in series between the power supply terminal of the second amplifier and the ground, and the magnetic bead is connected in series between the first power supply and the power supply terminal of the second amplifier.

10. A motor device, characterized in that: The motor device comprises a window motor and an anti-pinch detection circuit as claimed in any one of claims 1 to 9.

Images