Differential pressure shaping circuit and magnetic control key board magnetic induction switch circuit thereof

Abstract

The utility model relates to the technical field of magnetic control key boards, in particular to a differential pressure shaping circuit and a magnetic control key board magnetic induction switch circuit thereof, which comprise a first triode Q1, a second triode Q2 and a third triode Q3, an emitting electrode of the first triode Q1 is connected with a resistor R5, the other end of the resistor R5 is grounded, and the other end of the resistor R5 is grounded. The collector electrode and the base electrode of the second triode Q2 are both connected with the collector electrode of the first triode Q1, the emitter electrode of the second triode Q2 is connected with the emitter electrode of the first triode Q1, the collector electrode and the base electrode of the third triode Q3 are both connected with the collector electrode of the second triode Q2, and the emitter electrode of the third triode Q3 is grounded. According to the utility model, hysteresis causes the delay of the waveform of the output voltage of the drive circuit, and the delay time of the output signal is at the NS level through differential pressure shaping, so that the requirement of real-time control of the key can be met, and the reliability of real-time control of the key is greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of magnetic control keypad technology, and in particular to a differential pressure shaping circuit and its magnetic control keypad magnetic induction switch circuit. Background Technology

[0002] The working principle of the magnetic induction switch circuit on the magnetic control button board is as follows: When the magnetic field strength is lower than the sensitivity of the electromagnetic induction chip, and the magnetic field is perpendicular to the semiconductor surface of the magnetic induction chip, a weak potential difference is generated at the two ends of the semiconductor chip. The signal enters the amplifier for amplification, and after passing through a low-pass filter to remove high-frequency signals, due to the inherent hysteresis characteristics of magnetic induction, the output waveform of the drive circuit has a delay time. When the magnetic control button is pressed, the driver outputs a low level, and the delay time from t0 to t1 for the output signal voltage to go from low level (OL) to high level threshold level (V+) is 0.5S-1.2S. When the magnetic control button is released, the magnetic field disappears, and the driver outputs a low level with another delay time. From t2 to t3, there is another delay time of 0.4S-1S. If this output delay caused by hysteresis occurs, real-time field control of the button will be unreliable (for example, the control instrument cannot respond in time to the start and emergency stop buttons of the control system, causing the control system to malfunction). Utility Model Content

[0003] The technical problem to be solved by this utility model is: in order to solve the technical problem of unreliable real-time field control of the magnetic control keypad magnetic induction switch circuit with hysteresis output S-level delay, this utility model provides a differential pressure shaping circuit and its magnetic control keypad magnetic induction switch circuit. By improving the magnetic control keypad magnetic induction switch circuit, the hysteresis delay time is adjusted from S-level (second level) to NS-level (nanosecond level) to improve the reliability of real-time field control of the keypad.

[0004] The technical solution adopted by this utility model to solve its technical problem is: a differential pressure shaping circuit, including: a first transistor Q1, a second transistor Q2 and a third transistor Q3, wherein the emitter of the first transistor Q1 is connected to a resistor R5, the other end of the resistor R5 is grounded, the collector and base of the second transistor Q2 are both connected to the collector of the first transistor Q1, the emitter of the second transistor Q2 is connected to the emitter of the first transistor Q1, the collector and base of the third transistor Q3 are both connected to the collector of the second transistor Q2, and the emitter of the third transistor Q3 is grounded.

[0005] Therefore, the hysteresis causes a delay in the output voltage waveform of the drive circuit. After differential pressure shaping, the output signal delay time is in the ns range, which can meet the requirements of real-time button control and greatly improve the reliability of real-time button control.

[0006] Furthermore, it also includes a resistor R1, with the base of the first transistor Q1 connected to one end of the resistor R1.

[0007] Furthermore, it also includes: resistors R3, R7, and R10. One end of resistor R3 is connected to the collector of the first transistor Q1, one end of resistor R7 is connected to the collector of the second transistor Q2, one end of resistor R10 is connected to the collector of the third transistor Q3, and the other ends of resistors R3, R7, and R10 are all connected to a 3.3V power supply.

[0008] Furthermore, it also includes: a resistor R4, the two ends of which are connected to the collector of the first transistor Q1 and the base of the second transistor Q2, respectively.

[0009] Furthermore, it also includes: resistor R6, one end of which is connected to the base of the second transistor Q2, and the other end of which is grounded.

[0010] Furthermore, it also includes: a resistor R8, the two ends of which are connected to the collector of the second transistor Q2 and the base of the third transistor Q3, respectively.

[0011] Furthermore, it also includes: resistor R9, one end of which is connected to the base of the third transistor Q3, and the other end of which is grounded.

[0012] Furthermore, the first transistor Q1, the second transistor Q2, and the third transistor Q3 are all model 2N3904.

[0013] A magnetic control keypad magnetic induction switch circuit for differential pressure shaping circuit, comprising a differential pressure shaping circuit, a magnetic induction chip, an amplifier, a low-pass filter, and a driver, wherein the magnetic induction chip, the amplifier, the low-pass filter, the driver, and the differential pressure shaping circuit are connected in sequence.

[0014] Furthermore, the magnetic induction chip is externally protected by a fence-like magnetic shield; the driver is connected to the other end of resistor R1.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] Hysteresis causes a delay in the output voltage waveform of the drive circuit. After differential pressure shaping, the output signal delay time is in the ns range, which can meet the requirements of real-time button control and greatly improve the reliability of real-time button control. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a circuit diagram of the differential pressure shaping circuit of this utility model;

[0019] Figure 2 This is a comparison diagram of the input and output waveforms of the differential pressure shaping circuit of this utility model;

[0020] Figure 3 This is a schematic diagram of the magnetic induction switch circuit of the magnetic control keypad of this utility model.

[0021] In the diagram: 1. First transistor Q1; 2. Second transistor Q2; 3. Third transistor Q3; 4. Magnetic induction chip; 401. Fence-type magnetic shield; 5. Amplifier; 6. Low-pass filter; 7. Driver. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0024] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] like Figures 1 to 2The diagram shows the preferred embodiment of this invention. The differential voltage shaping circuit of this embodiment includes: a first transistor Q11, a second transistor Q22, and a third transistor Q33. The emitter of the first transistor Q11 is connected to a resistor R5, the other end of which is grounded. The collector and base of the second transistor Q22 are both connected to the collector of the first transistor Q11, and the emitter of the second transistor Q22 is connected to the emitter of the first transistor Q11. The collector and base of the third transistor Q33 are both connected to the collector of the second transistor Q22, and the emitter of the third transistor Q33 is grounded. Therefore, the hysteresis-induced delay in the output voltage waveform of the drive circuit is reduced to the nanosecond (NS) level after differential voltage shaping, meeting the requirements of real-time button control and greatly improving the reliability of real-time button control.

[0026] Specifically, using integrated chips (e.g., operational amplifiers, comparators) for large differential pressure adjustment is quite difficult; using operational amplifiers with a single power supply results in an output signal level of 0 at 1 / 2VCC, and the shaped waveform is ±1 / 2VCC, which is unsuitable for control instrument buttons; using comparators, large differential pressure cannot be adjusted; this differential pressure adjustment uses a discrete transistor circuit. For the output voltage of driver 7, it rises from OL to V+ (open threshold) to achieve V+>2V, which can adjust the collector current of the first transistor Q11 (3.3V-VR5 / R2) and the first transistor... The base current of Q11 (2V - 0.6V / R1) decreases from VOH to V- (off threshold) for the output voltage of driver 7, achieving V- < 1.5V. This allows adjustment of the collector current of the second transistor Q22 (3.3V - VR5 / R3) and the base current of the second transistor Q22 (2V - 0.6V / R8). Adjusting the resistance of R5 in the circuit adjusts V+ (on threshold), and adjusting the resistance of R3 in the circuit adjusts V- (off threshold). This differential voltage shaping circuit allows for flexible and convenient adjustment of the differential voltage required by the system.

[0027] In this embodiment, the system further includes resistors R1, R3, R7, R10, R4, R6, R8, and R9. The base of the first transistor Q11 is connected to one end of resistor R1. One end of resistor R3 is connected to the collector of the first transistor Q11. One end of resistor R7 is connected to the collector of the second transistor Q22. One end of resistor R10 is connected to the collector of the third transistor Q33. The other ends of resistors R3, R7, and R10 are all connected to a 3.3V power supply. The resistor R4 is connected to the collector of transistor Q11 and the base of transistor Q22, respectively. One end of resistor R6 is connected to the base of transistor Q22, and the other end of resistor R6 is grounded. The two ends of resistor R8 are connected to the collector of transistor Q22 and the base of transistor Q33, respectively. One end of resistor R9 is connected to the base of transistor Q33, and the other end of resistor R9 is grounded. Transistors Q11, Q22, and Q33 are all model 2N3904.

[0028] The working principle of this differential pressure shaping circuit is as follows: The magnetic induction chip 4 has a hysteresis loop, which causes the driver 7 to output a differential pressure: V+ and V-. When the output of the magnetic induction chip 4 is within the time interval t0-t1, the input signal < V+, the first transistor Q11 is cut off, and the output is high level. The second transistor Q22 is turned on, and the current at the collector of the second transistor Q22 flows into the resistor R5, generating a voltage drop. This causes the emitter of the first transistor Q11 to be reverse biased, causing positive feedback, which further turns off the first transistor Q11. The collector of the second transistor Q22 outputs a low level, and the base of the third transistor Q33... When there is no current at terminal b, the third transistor Q33 is cut off, and its collector c outputs a high level. When the input signal is greater than V+, the first transistor Q11 is turned on, and its collector c outputs a low level. The voltage drop generated by the collector current of the first transistor Q11 through resistor R5 causes the emitter e of the second transistor Q22 to be reverse biased, resulting in positive feedback, which further turns off the second transistor Q22. The high level output of the collector c of the second transistor Q22 causes a bias current at the base of the third transistor Q33, and its collector c outputs a low level.

[0029] like Figure 3 As shown, the differential pressure shaping circuit, magnetic induction chip 4, amplifier 5, low-pass filter 6, and driver 7 are connected in sequence.

[0030] In this embodiment, a fence-type magnetic shield 401 is provided on the outside of the magnetic induction chip 4; the driver 7 is connected to the other end of the resistor R1.

[0031] In summary, the delay in the output voltage waveform of the drive circuit caused by the hysteresis of the utility model, after differential pressure shaping, reduces the output signal delay time to the N / s level, which can meet the requirements of real-time button control and greatly improve the reliability of real-time button control.

[0032] The above description is based on the preferred embodiments of this utility model. Through the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A differential pressure shaping circuit, characterized in that, include: The first transistor Q1(1) has a resistor R5 connected to its emitter, and the other end of the resistor R5 is grounded. The second transistor Q2(2) has its collector and base connected to the collector of the first transistor Q1(1), and its emitter connected to the emitter of the first transistor Q1(1). The collector and base of the third transistor Q3(3) are both connected to the collector of the second transistor Q2(2), and the emitter of the third transistor Q3(3) is grounded.

2. The differential pressure shaping circuit according to claim 1, characterized in that, Also includes: Resistor R1, the base of the first transistor Q1(1) is connected to one end of resistor R1.

3. The differential pressure shaping circuit according to claim 1, characterized in that, Also includes: Resistors R3, R7, and R10 are provided. One end of resistor R3 is connected to the collector of the first transistor Q1 (1), one end of resistor R7 is connected to the collector of the second transistor Q2 (2), and one end of resistor R10 is connected to the collector of the third transistor Q3 (3). The other ends of resistors R3, R7, and R10 are all connected to a 3.3V power supply.

4. The differential pressure shaping circuit according to claim 1, characterized in that, Also includes: Resistor R4, with its two ends connected to the collector of the first transistor Q1 (1) and the base of the second transistor Q2 (2), respectively.

5. The differential pressure shaping circuit according to claim 1, characterized in that, Also includes: Resistor R6, one end of which is connected to the base of the second transistor Q2(2), and the other end of which is grounded.

6. The differential pressure shaping circuit according to claim 1, characterized in that, Also includes: Resistor R8, with its two ends connected to the collector of the second transistor Q2 (2) and the base of the third transistor Q3 (3), respectively.

7. The differential pressure shaping circuit according to claim 1, characterized in that, Also includes: Resistor R9, one end of which is connected to the base of the third transistor Q3(3), and the other end of which is grounded.

8. The differential pressure shaping circuit according to claim 1, characterized in that, The first transistor Q1(1), the second transistor Q2(2), and the third transistor Q3(3) are all of model 2N3904.

9. A magnetic induction switch circuit for a magnetically controlled keypad of a differential pressure shaping circuit according to any one of claims 1-8, characterized in that, The device includes the differential pressure shaping circuit, the magnetic induction chip (4), the amplifier (5), the low-pass filter (6), and the driver (7), which are connected in sequence.

10. The magnetic control keypad magnetic induction switch circuit of the differential pressure shaping circuit according to claim 9, characterized in that, The magnetic induction chip (4) is provided with a fence-type magnetic shield (401) on its exterior; The driver (7) is connected to the other end of the resistor R1.

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