Capacitive sensor input anti-reverse protection circuit

Abstract

The utility model relates to the technical field of protection circuits, in particular to a capacitive sensor input anti-reverse protection circuit which comprises a protection assembly, a first diode connected with one side of the protection assembly in series and a first voltage stabilizing capacitor connected with the first diode in parallel. The side, away from the first diode, of the protection assembly is connected with the control part in series, the forward conduction direction of the first diode is consistent with the direction of current flowing from the control part to the socket, one end of the first voltage stabilizing capacitor is connected with the protection assembly in series, and the other end of the first voltage stabilizing capacitor is connected with the socket in series. According to the invention, when the reverse voltage is applied, the control element is prevented from being damaged, and meanwhile, the capacitance sensor keeps a normal detection function.

Description

Technical Field

[0001] This application relates to the field of protection circuit technology, and in particular to a reverse protection circuit for capacitive sensor input. Background Technology

[0002] A capacitive sensor is a sensor that detects changes in external physical quantities by detecting changes in the capacitance value. A capacitive sensor typically includes a sensing element and a control element. One end of the control element is electrically connected to the sensing element, and the other end is electrically connected to a power supply and a LIN bus. The sensing element senses changes in the external physical quantity and generates a change in capacitance. The control element receives this change and outputs a control signal based on it. During the detection of changes in the external physical quantity, if a reverse voltage is generated in the circuit, the control element will be damaged under the influence of the reverse voltage.

[0003] Therefore, to optimize the control component's performance and prevent damage under reverse voltage, a diode needs to be connected in series in the detection circuit. When a forward voltage is applied to the circuit, the diode conducts, and the control component operates normally; when a reverse voltage is applied, the diode is cut off, and the control component loses its normal detection function.

[0004] In response to the situation where the control component loses its normal detection function, this application proposes a reverse protection circuit for a capacitive sensor input to prevent damage to the control component when a reverse voltage is applied, while maintaining the normal detection function of the capacitive sensor. Utility Model Content

[0005] In order to prevent damage to the control components when a reverse voltage is applied, while maintaining the normal detection function of the capacitive sensor, this application provides a reverse input protection circuit for a capacitive sensor.

[0006] This application provides a capacitor sensor input reverse protection circuit, which adopts the following technical solution:

[0007] A reverse protection circuit for a capacitive sensor input includes: a protection component, a first diode connected in series with one side of the protection component, and a first voltage-stabilizing capacitor connected in parallel with the first diode. The side of the protection component away from the first diode is connected in series with a control component. The forward conduction direction of the first diode is consistent with the direction of current flow from the control component to the socket. One end of the first voltage-stabilizing capacitor is connected in series with the protection component, and the other end of the first voltage-stabilizing capacitor is connected in series with the socket.

[0008] By adopting the above technical solution, when a reverse voltage is input across the first diode, a reverse voltage is generated across the protection device. At this time, under the action of the first diode, the control device is not affected by the reverse voltage. At the same time, under the action of the first voltage stabilizing capacitor, a small reverse current is generated in the anti-reverse circuit to meet the requirements of the control device. The control device can normally detect the capacitance change, thus realizing that when a reverse voltage is applied, the capacitor sensor control device is protected from damage, while the capacitor sensor maintains its normal detection function.

[0009] Optionally, the protection component includes a first resistor and a first filter capacitor. One end of the first resistor is connected in series with the control element, and the other end of the first resistor is connected in series with the first diode. One end of the first filter capacitor is connected in series with the first resistor, and the other end of the first filter capacitor is grounded.

[0010] By adopting the above technical solution, when the external physical quantity changes, the capacitance of the first filter capacitor changes. At this time, a positive voltage is formed in the anti-reverse circuit. Under the action of the first resistor, the positive voltage forms a positive current within the operating range of the controller. The setting of the first filter capacitor reduces the fluctuation of the positive current and improves the stability of the electrical signal. The controller receives and outputs a control signal based on the electrical signal in the protection circuit.

[0011] Optionally, the protection component further includes a second resistor and a second filter capacitor. One end of the second resistor is connected in series with the first diode, and the other end of the second resistor is connected in series with the first resistor. One end of the second filter capacitor is connected in series with the second resistor, and the other end of the second filter capacitor is grounded.

[0012] By adopting the above technical solution, the first filter capacitor and the second filter capacitor work together to perform filtering. When either component is damaged, the other component continues to work, which increases the stability of the anti-reverse circuit.

[0013] Optionally, the protection component further includes a first protection element, one end of which is connected in series with the first diode, and the other end of which is grounded.

[0014] By adopting the above technical solution, when there is static electricity in the external environment, the static electricity is discharged through the first protective element, which reduces the impact of external static electricity on the internal components of the capacitive energy sensor and provides a stable environment for the operation of the capacitive energy sensor.

[0015] Optionally, it also includes a sensing component, a second diode, and a second voltage-stabilizing capacitor, wherein the sensing component, the second diode, and the second voltage-stabilizing capacitor are respectively disposed opposite to the protection component, the first diode, and the first voltage-stabilizing capacitor; the sensing component includes a third resistor, a fourth resistor, a third filter capacitor, a fourth filter capacitor, and a second protection element, wherein the above components correspond to the first resistor, the second resistor, the first filter capacitor, the second filter capacitor, and the first protection element in the protection component, wherein the third resistor is connected in series with the control component, and the second protection element is connected to the socket.

[0016] By adopting the above technical solution, when either the circuit containing the protection component or the circuit containing the sensing component is short-circuited, the other circuit can still work normally, which increases the stability of the capacitive sensor during operation.

[0017] Optionally, a first induction coil is connected in series with the first diode, and a second induction coil is connected in series with the second diode.

[0018] By adopting the above technical solution, under the action of the first induction coil and the second induction coil, when a change in current occurs in the circuit, the change in current is relatively gradual, thus slowing down the process of current change in the circuit.

[0019] Optionally, the first induction coil and the second induction coil are arranged opposite to each other, and the first induction coil and the second induction coil are mutually inductive.

[0020] By adopting the above technical solution, the electrical signal in the anti-reverse circuit is propagated through the mutual inductance between the first induction coil and the second induction coil, which increases the working stability of the capacitive sensor and achieves electrical isolation, reducing signal interference between the two circuits.

[0021] In summary, this application includes at least one of the following beneficial technical effects:

[0022] 1. When a reverse voltage is generated in the anti-reverse circuit, the protection circuit is reverse-cut off under the action of the first diode. The capacitance of the first voltage-stabilizing capacitor changes under the action of the reverse voltage. The controller receives and outputs an electrical signal based on the capacitance change of the first voltage-stabilizing capacitor. The control signal is received through the communication device and outputs a control signal based on the electrical signal. This realizes that when a reverse voltage is applied, the control device is protected from damage, while the capacitance sensor maintains normal detection function.

[0023] 2. When any component in the protection component or the sensing component fails, the other circuit continues to operate normally, increasing the stability of the capacitive sensor during operation.

[0024] 3. When the current changes in the anti-reverse circuit, the first and second induction coils self-induct, preventing the protection circuit from changing with the induced current, thus making the current change relatively stable. Attached Figure Description

[0025] Figure 1 This is a circuit diagram of a capacitor sensor input reverse protection circuit according to an embodiment of this application.

[0026] Figure 2 This is a normal operation flowchart of the capacitor sensor input reverse protection circuit in the embodiments of this application.

[0027] Figure 3 This is a flowchart illustrating the operation of the reverse protection circuit for the capacitive sensor input when a reverse voltage is applied, as described in this application embodiment.

[0028] Reference numerals: 1. Protection component; 2. First diode; 3. First voltage-stabilizing capacitor; 11. First resistor; 12. First filter capacitor; 13. Second resistor; 14. Second filter capacitor; 15. First protection element; 4. Sensing component; 5. Second diode; 6. Second voltage-stabilizing capacitor; 41. Third resistor; 42. Fourth resistor; 43. Third filter capacitor; 44. Fourth filter capacitor; 45. Second protection element; 7. First induction coil; 8. Second induction coil; 9. Control component; 10. Voltage regulator; 101. Communication component. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0030] This application discloses a reverse input protection circuit for a capacitive sensor.

[0031] Reference Figure 1 and Figure 2 A reverse protection circuit for a capacitive sensor input includes a control component, a protection component 1, a first diode 2, and a first voltage-stabilizing capacitor 3. The control component includes a control element 9, a voltage regulator 10 electrically connected to the control element 9, and a communication element 101 electrically connected to the control element 9. The input terminal of the voltage regulator 10 is connected to an external power supply, and the output terminal is connected to the control element 9. One end of the communication element 101 is electrically connected to the control element 9, and the other end is electrically connected to a LIN bus. The side of the control element 9 away from the voltage regulator 10 is electrically connected to the protection component 1. The protection component 1 is electrically connected to the positive terminal of the first diode 2. The first diode 2 is electrically connected to a socket. The first voltage-stabilizing capacitor 3 is connected in parallel with the first diode 2.

[0032] In this embodiment, the control component 9 is preferably a capacitive sensor control chip, the voltage regulator 10 is preferably a power supply regulator chip, the communication component 101 is preferably a LIN transceiver, the first diode 2 is preferably a dedicated diode with low forward voltage, low reverse current, and low junction current, and the first voltage-stabilizing capacitor 3 is preferably a capacitor with a capacitance of 1nF and a withstand voltage of 25V or higher. When a forward voltage is applied in the protection circuit, the first diode 2 conducts. When the external physical quantity changes, the protection circuit receives a detection signal. Under the protection of the protection component 1, the detection signal is easily received by the control component 9. The control component 9 detects and outputs an electrical signal based on the detection signal in the protection circuit. The communication component 101 receives and outputs a control signal to the LIN bus based on the electrical signal sent by the control component 9, thus realizing the working process of the capacitive sensor.

[0033] Reference Figure 1 and Figure 3 The protection component 1 includes a first resistor 11 connected in series with the control element 9, a first filter capacitor 12 connected in series with the end of the first resistor 11 away from the control element 9, a second filter capacitor 14 connected in series with the end of the first resistor 11 away from the control element 9, and a second resistor 13 connected in series with the end of the first resistor 11 away from the control element 9. The ends of the first filter capacitor 12 and the second filter capacitor 14 away from the first resistor 11 are both grounded. One end of the first protection element 15 is connected in series with the second resistor 13, and the other end of the first protection element 15 is grounded. The end of the second resistor 13 away from the first resistor 11 is electrically connected to the socket.

[0034] When a reverse voltage occurs in the protection circuit, the first diode 2 is cut off. At this time, the first filter capacitor 12 and the second filter capacitor 14 receive and generate capacitance changes based on the changes in external physical quantities. The first voltage regulator capacitor 3 generates capacitance changes based on the above capacitance changes. The controller receives and outputs an electrical signal based on the capacitance changes of the first voltage regulator capacitor 3, thus realizing the normal operation of the controller under the state of the first diode 2 being cut off.

[0035] Reference Figure 1 The protection component 1 further includes a first protection element 15. One end of the first protection element 15 is electrically connected to the negative terminal of the first diode 2, and the other end of the first protection element 15 is grounded. In this embodiment, the first protection element 15 is preferably an electrostatic impedance device. When a voltage is generated in the protection circuit, under the protection of the first protection element 15, the static electricity in the capacitive sensor is released through the grounding of the first protection element 15, reducing the risk of damage to the capacitive sensor under the action of static electricity.

[0036] Reference Figure 1The protection circuit has a first induction coil 7 connected in series. One end of the first induction coil 7 is connected in series with the first resistor 11, and the other end of the first induction coil 7 is connected in series with the second resistor 13. When the current in the protection circuit changes, the first induction coil 7 has a self-inductance. The self-inductance of the first induction coil 7 opposes the change in current, and the change in current is relatively stable, which increases the stability of the capacitive sensor when it is working.

[0037] Reference Figure 1 The sensing component 4 includes a third resistor 41, a fourth resistor 42, a third filter capacitor 43, a fourth filter capacitor 44, a second voltage regulator capacitor 6, a second diode 5, a second protection element 45, and a first induction coil 7. These components correspond to the first resistor 11, the second resistor 13, the first filter capacitor 12, the second filter capacitor 14, the first voltage regulator capacitor 3, the first diode 2, the first protection element 15, and the second induction coil 8 located in the protection circuit, and have the same function. When either the protection component 1 or the sensing component 4 is in a faulty circuit, the other circuit will still work normally, increasing the stability of the capacitive sensor during operation.

[0038] The implementation principle of the reverse protection circuit for a capacitive sensor input in this application embodiment is as follows: When a reverse voltage occurs in the protection circuit, the first diode 2 is cut off under the action of the reverse voltage. At this time, the capacitive sensor detects the change of external physical quantity and inputs an electrical signal into the protection circuit. The first filter capacitor 12 and the second filter capacitor 14 work together to reduce the current fluctuation in the electrical signal. The first voltage stabilizing capacitor 3 detects and receives the above electrical signal and generates a capacitance change. The controller receives and outputs a control signal based on the capacitance change of the first voltage stabilizing capacitor 3, thereby realizing that when a reverse voltage is applied, the control component 9 is protected from damage, while the capacitive sensor maintains normal detection function.

[0039] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A reverse input protection circuit for a capacitive sensor, characterized in that, include: The protection component (1), a first diode (2) connected in series with one side of the protection component (1), and a first voltage-stabilizing capacitor (3) connected in parallel with the first diode (2). The side of the protection component (1) away from the first diode (2) is connected in series with the control component. The forward conduction direction of the first diode (2) is consistent with the direction of current flow from the control component to the socket. One end of the first voltage-stabilizing capacitor (3) is connected in series with the protection component (1), and the other end of the first voltage-stabilizing capacitor (3) is connected in series with the socket.

2. The input reverse protection circuit for a capacitive sensor according to claim 1, characterized in that: The protection component (1) includes a first resistor (11) and a first filter capacitor (12). One end of the first resistor (11) is connected in series with the control component, and the other end of the first resistor (11) is connected in series with the first diode (2). One end of the first filter capacitor (12) is connected in series with the first resistor (11), and the other end of the first filter capacitor (12) is grounded.

3. The input reverse protection circuit for a capacitive sensor according to claim 2, characterized in that: The protection component (1) further includes a second resistor (13) and a second filter capacitor (14). One end of the second resistor (13) is connected in series with the first diode (2), and the other end of the second resistor (13) is connected in series with the first resistor (11). One end of the second filter capacitor (14) is connected in series with the second resistor (13), and the other end of the second filter capacitor (14) is grounded.

4. The input reverse protection circuit for a capacitive sensor according to claim 3, characterized in that: The protection component (1) further includes a first protection element (15), one end of which is connected in series with the first diode (2), and the other end of which is grounded.

5. The input reverse protection circuit for a capacitive sensor according to claim 4, characterized in that: It also includes a sensing component (4), a second diode (5), and a second voltage-stabilizing capacitor (6), wherein the sensing component (4), the second diode (5), and the second voltage-stabilizing capacitor (6) are respectively disposed opposite to the protection component (1), the first diode (2), and the first voltage-stabilizing capacitor (3); the sensing component (4) includes a third resistor (41), a fourth resistor (42), a third filter capacitor (43), a fourth filter capacitor (44), and a second protection element (45), wherein the above components correspond to the first resistor (11), the second resistor (13), the first filter capacitor (12), the second filter capacitor (14), and the first protection element (15) in the protection component (1), wherein the third resistor (41) is connected in series with the control component, and the second protection element (45) is connected to the socket.

6. The input reverse protection circuit for a capacitive sensor according to claim 5, characterized in that: A first induction coil (7) is connected in series with the first diode (2), and a second induction coil (8) is connected in series with the second diode (5).

7. The input reverse protection circuit for a capacitive sensor according to claim 6, characterized in that: The first induction coil (7) and the second induction coil (8) are arranged opposite to each other, and the first induction coil (7) and the second induction coil (8) are mutually inductive.

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