A transmission circuit and method for transmitting direction and speed signals of a three-wire DC motor.

Abstract

This invention discloses a transmission circuit and method for transmitting direction and speed signals of a three-wire DC motor. The circuit includes a positive terminal for the motor power supply, a negative terminal for the motor speed control, a grounding transmission terminal, and a Hall sensor. The positive terminal for the motor power supply and the negative terminal for the motor speed control are electrically connected to the positive voltage terminal of the Hall sensor via a rectifier filter circuit and a voltage regulator circuit. The grounding transmission terminal is electrically connected to the ground terminal of the Hall sensor. The direction and speed signal output pins are electrically connected to the Hall ground terminal via a signal superposition circuit, so that the direction and speed signals generated by the Hall sensor are superimposed with the static current of the voltage regulator circuit and the Hall sensor, and then transmitted through the grounding transmission terminal. This invention allows two of the three wires of a DC motor to be used for powering the motor and the Hall sensor, while the third wire, in addition to being used for anti-interference grounding, can also be used to transmit the direction signal, speed signal, static current of the Hall sensor, and static current of the voltage regulator circuit.

Description

Technical Field

[0001] This invention relates to a DC motor control circuit, and more particularly to a transmission circuit and method for transmitting the direction and speed signals of a three-wire DC motor. Background Technology

[0002] Existing DC gate opener motor wiring typically uses a 3-core cable: ① positive power supply line, ② negative PWM speed control line, and ③ anti-interference grounding line. If the control system requires more precise motor control, a Hall effect sensor is needed to provide feedback on the motor's actual speed and direction signals, requiring separate wiring for the Hall effect sensor. For Hall effect sensors with direction signals, four additional lines are generally needed: ① positive power supply line, ② negative power supply line, ③ direction signal line, and ④ speed signal line. This increases the number of motor leads to seven. This is quite disadvantageous for gate sales, as most gate opening systems use 3-core pre-installed cables. Installing a 7-core motor requires rewiring. For users with pre-installed 3-core cables or those replacing older models, it may require excavation and rewiring, increasing installation workload, costs, and cable costs. Summary of the Invention

[0003] One objective of this invention is to provide a simple, reasonable, and low-cost transmission circuit for the direction and speed signals of a three-wire DC motor.

[0004] One objective of this invention is achieved as follows:

[0005] A transmission circuit for the direction and speed signals of a three-wire DC motor includes a positive terminal for the motor power supply, a negative terminal for the motor speed control, and a grounding transmission terminal. It also includes a multi-pole magnetic ring mounted on the DC motor shaft and a Hall sensor driven by the multi-pole magnetic ring. The Hall sensor has a Hall positive voltage terminal, a direction signal output pin, a speed signal output pin, and a Hall ground terminal. The positive terminal for the motor power supply and the negative terminal for the motor speed control are electrically connected to the Hall positive voltage terminal through a rectifier filter circuit and a voltage regulator circuit. The grounding transmission terminal is electrically connected to the Hall ground terminal. The direction signal output pin and the speed signal output pin are indirectly or directly electrically connected to the Hall ground terminal through a signal superposition circuit, so that the direction and speed signals generated by the Hall sensor are superimposed with the static current of the voltage regulator circuit and the Hall sensor, and then transmitted through the grounding transmission terminal. This technology fully utilizes the existing 3-core cable (the 3-core cable is connected to the aforementioned positive terminal for the motor power supply, the negative terminal for the motor speed control, and the grounding transmission terminal respectively). After circuit processing, it simultaneously achieves the functions of forward and reverse rotation control, PWM speed regulation, and transmission of real-time speed and direction signals of the DC motor. This reduces the material costs of cables and matching terminals, as well as the installation costs of the gate opener.

[0006] One objective of the present invention can also be achieved by the following technical measures:

[0007] As a more specific embodiment, the voltage regulator circuit and the signal superposition circuit include a voltage regulator, a first pull-up resistor and a second pull-up resistor. The voltage regulator has a positive pin, a regulated output pin and a negative pin. The positive pin of the voltage regulator is electrically connected to the positive terminal of the motor power supply and the negative terminal of the motor speed control through the rectifier and filter circuit.

[0008] The negative pin of the voltage regulator is electrically connected to the ground transmission terminal; the Hall sensor is an internally open-drain Hall sensor with direction, and the voltage regulator's regulated output pin is electrically connected to the speed signal output pin and direction signal output pin of the Hall sensor through a first pull-up resistor and a second pull-up resistor, respectively, so that the two currents generated by the speed signal output pin and the direction signal output pin can indirectly flow out to the ground transmission terminal through the Hall ground terminal.

[0009] The voltage regulator's regulated output pin is also electrically connected to the Hall positive voltage terminal of the Hall sensor via a power isolation circuit.

[0010] The voltage regulator is a high-voltage regulator, and the voltage regulator output pin provides a 5V output. The resistance values ​​of the first pull-up resistor and the second pull-up resistor are both 1K, so that the current amplification of the Hall ground terminal is 0mA or 5mA.

[0011] As a further alternative, the voltage regulator circuit and the signal superposition circuit include a voltage regulator, a first transistor and a second transistor. The voltage regulator has a positive pin, a regulated output pin and a negative pin. The positive pin of the voltage regulator is electrically connected to the positive terminal of the motor power supply and the negative terminal of the motor speed control through the rectifier and filter circuit.

[0012] The negative pin of the voltage regulator is electrically connected to the ground transmission terminal; the Hall sensor is a Hall sensor with direction, the voltage regulator's regulated output pin is electrically connected to the collector of the first transistor and the collector of the second transistor, the direction signal output pin and the speed signal output pin of the Hall sensor are electrically connected to the base of the first transistor and the base of the second transistor, respectively, and the emitters of the first transistor and the second transistor are electrically connected to the ground transmission terminal, so that the two currents generated by the direction signal output pin and the speed signal output pin are directly inverted by the first transistor and the second transistor and then output to the ground transmission terminal.

[0013] The voltage regulator's regulated output pin is also electrically connected to the Hall positive voltage terminal of the Hall sensor via a power isolation circuit.

[0014] The voltage regulator is a high-voltage regulator, and the voltage regulation output pin provides a 5V output. The voltage regulation output pin is electrically connected to the collector of the first transistor and the collector of the second transistor through a first resistor and a second resistor, respectively. The resistance values ​​of the first resistor and the second resistor are both 1K. The direction signal output pin and the speed signal output pin are electrically connected to the power isolation circuit through a third resistor and a fourth resistor, respectively.

[0015] The aforementioned power isolation circuit can reduce the impact of Hall signal output on the Hall power supply ripple.

[0016] As a further embodiment, the voltage regulator circuit also includes a voltage regulator protection circuit, which includes a unidirectional transient diode (unidirectional TVS diode) connected between the positive and negative terminals. The unidirectional TVS diode is used to protect the voltage regulator from damage caused by voltage spikes.

[0017] As a further solution, the Hall sensor is mounted on a carbon brush plate, which has two carbon brush electrodes that are electrically connected to the positive terminal of the motor power supply and the negative terminal of the motor speed control, respectively. The carbon brush plate is also equipped with a motor electromagnetic compatibility suppression device, which helps to absorb high-frequency noise in a specific frequency band and facilitates EMC certification.

[0018] As a further improvement, a bidirectional transient diode (bidirectional TVS diode) is also provided between the two carbon brush electrodes. The bidirectional TVS diode is used to suppress voltage spikes generated during motor operation to protect other circuits.

[0019] Another objective of this invention is to provide a simple method for transmitting the direction and speed signals of a three-wire DC motor.

[0020] Another object of the present invention is achieved as follows:

[0021] A method for transmitting direction and speed signals of a three-wire DC motor is provided. A Hall sensor is used to detect the multipole magnetic ring on the DC motor shaft. The power supply of the DC motor is regulated by a voltage regulator circuit and then used to power the Hall sensor. The speed signal and direction signal of the Hall sensor are superimposed and transmitted through a ground wire. At the same time, the ground wire is compatible with the anti-interference grounding of the DC motor, the static current of the voltage regulator circuit, and the static current of the Hall sensor.

[0022] Another objective of the present invention can also be achieved by the following technical measures:

[0023] As a more specific approach, the speed and direction of the DC motor can be analyzed from the ground current signal using a dual-channel current comparator or an AD sampling circuit.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) In this invention, the Hall sensor is powered by the drive power supply of the DC motor. The positive voltage of the Hall sensor is provided by the positive terminal of the motor power supply and the negative terminal of the motor speed control when the motor is running in the forward or reverse direction, or by the positive terminal of the motor power supply and the negative terminal of the motor speed control when the motor is stopped. The negative voltage of the Hall sensor is provided by the ground transmission terminal.

[0026] (2) In this invention, the direction signal and speed signal of the Hall sensor are superimposed and transmitted out from the ground wire of the Hall sensor.

[0027] (3) Based on the original three-wire connection of the DC motor (without damaging the original wiring), this invention allows two of the wires to be used for power supply to the motor and Hall sensor, while the other wire, in addition to being used for anti-interference grounding, can also be used to transmit the direction signal, speed signal, static current of the Hall sensor, and static current of the voltage regulator circuit. Therefore, under the same performance conditions, the installation and material costs are lower than those of similar circuits; under similar cost conditions, the performance is better, the control is more precise, and it is more suitable for the application of pre-buried motor wires in courtyard gates, thus improving the competitiveness of the product. Attached Figure Description

[0028] Figure 1 This is a circuit diagram of an embodiment of the present invention.

[0029] Figure 2 for Figure 1 The current waveform at the ground transmission terminal in the circuit.

[0030] Figure 3 This is a circuit diagram of another embodiment of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0032] Example 1, see Figure 1As shown, a transmission circuit for the direction and speed signals of a three-wire DC motor includes a positive terminal J2 for the motor power supply, a negative terminal J5 for the motor speed control, and a ground transmission terminal J8. It also includes a multi-pole magnetic ring mounted on the DC motor shaft and a Hall sensor U1 driven by the multi-pole magnetic ring. The Hall sensor U1 has a Hall positive voltage terminal VCC, a direction signal output pin, a speed signal output pin, and a Hall ground terminal GND. The positive terminal J2 for the motor power supply and the negative terminal J5 for the motor speed control are electrically connected to the Hall positive voltage terminal VCC through a rectifier filter circuit and a voltage regulator circuit. The ground transmission terminal J8 is electrically connected to the Hall ground terminal GND. The direction signal output pin and the speed signal output pin are indirectly electrically connected to the Hall ground terminal GND through a signal superposition circuit, so that the direction signal and speed signal generated by the Hall sensor U1 are superimposed and transmitted through the ground transmission terminal J8.

[0033] The voltage regulator circuit and the signal superposition circuit include a voltage regulator IC1, a first pull-up resistor R5 and a second pull-up resistor R6. The voltage regulator IC1 has a positive pin VIN, a regulated output pin OUT and a negative pin GND. The positive pin VIN of the voltage regulator IC1 is electrically connected to the positive terminal J2 of the motor power supply and the negative terminal J5 of the motor speed control through the rectifier and filter circuit.

[0034] The rectifier and filter circuit includes diode D4, diode D2, inductor L3, and capacitor C10. For specific connection details, see [link to circuit diagram]. Figure 1 As shown.

[0035] The negative pin GND of the voltage regulator IC1 is electrically connected to the ground transmission terminal J8; the Hall sensor U1 is an internally open-drain Hall sensor with direction U1, and the regulated output pin OUT of the voltage regulator IC1 is electrically connected to the speed signal output pin and the direction signal output pin of the Hall sensor U1 through the first pull-up resistor R5 and the second pull-up resistor R6, respectively, so that the two currents generated by the speed signal output pin and the direction signal output pin indirectly flow out to the ground transmission terminal J8 through the Hall ground terminal GND.

[0036] The voltage regulator IC1's regulated output pin OUT is also electrically connected to the Hall positive voltage terminal VCC of the Hall sensor U1 through a power isolation circuit.

[0037] The voltage regulator IC1 is a high voltage regulator IC1. The voltage output pin OUT provides a 5V output. The resistance values ​​of the first pull-up resistor R5 and the second pull-up resistor R6 are both 1K, so that the current flowing out of the Hall ground terminal GND increases to 0mA or 5mA.

[0038] The power isolation circuit includes a diode D5 and a capacitor C2. One end of the diode D5 is electrically connected to the regulated output pin OUT, and one end of the capacitor C2 is electrically connected to the ground transmission terminal J8. The other ends of the diode D5, the other end of the capacitor C2, and the Hall positive voltage terminal VCC are electrically connected to each other.

[0039] The voltage regulator circuit also includes a voltage regulator protection circuit, which includes a unidirectional transient diode D3 connected between the positive pin VIN and the negative pin GND.

[0040] The Hall sensor U1 is mounted on a carbon brush plate, which has two carbon brush electrodes J3 and J4. These electrodes are electrically connected to the positive terminal J2 of the motor power supply and the negative terminal J5 of the motor speed control, respectively. The carbon brush plate also includes a motor electromagnetic compatibility (EMC) suppression device. This device comprises capacitors C3, C4, C5, C6, C7, C8, and C9, and inductors L1 and L2. The connection details of the motor EMC suppression device are provided below. Figure 1 As shown.

[0041] A bidirectional transient diode D6 is also provided between the two carbon brush electrodes J3 and J4.

[0042] The carbon brush plate is also provided with a grounding point J1 that is connected to the housing of the DC motor. This grounding point J1 is not wired.

[0043] The aforementioned Hall sensor U1 with directional characteristics is specifically a dual-channel Hall sensor, model YS2526; the high-voltage regulator (high-voltage LDO) IC1 is model SL6203H, with a withstand voltage of 80V; the unidirectional transient diode D3 is model SMAJ43A; the bidirectional transient diode D6 is model SMCJ48CA-T3; diodes D2, D4, and D5 are all silicon rectifier diodes (ordinary diode M7); the capacitor C2 has parameters of 105 / 5. 0V, capacitor C3 has parameters of 333 / 280V, capacitor C4 has parameters of 2200pF / 1000V, capacitor C5 has parameters of 82pF / 500V, capacitor C6 has parameters of 100pF / 1000V, capacitor C7 has parameters of 82pF / 500V, capacitor C8 has parameters of 2200pF / 1000V, capacitor C9 has parameters of 82pF / 500V, capacitor C10 has parameters of 105 / 50V; inductor L3 has parameters of 1mH.

[0044] Its working principle is as follows: a multi-pole magnetic ring, which is placed on the rotor shaft inside the motor, is positioned in front of the Hall sensor U1. When the motor is running, the Hall sensor U1 senses the rotation of the magnetic ring. Depending on the direction of rotation, the direction signal output pin of the Hall sensor U1 will output a DC high level of 5V or a low level of 0V. Because the chip uses an open-drain output with a pull-up resistor of 1K, the current increase from the Hall ground terminal GND of the Hall sensor U1 will increase by 0mA or 5mA depending on the direction of rotation.

[0045] The speed signal output pin of Hall sensor U1 outputs a square wave signal during magnet rotation. Since the pull-up resistor is 1K, the current amplification caused by it flowing from the Hall sensor ground terminal GND is 0mA or 5mA. The current waveform output at port J8 after the sum of the two currents and the static currents of IC1 and U1 is as follows: Figure 2 As shown.

[0046] This completes the function of transmitting the direction and speed signals of the Hall effect sensor, as well as the negative terminal of the Hall effect power supply, to the control board via a single line.

[0047] The control board (not shown in the figure) uses dual current comparators. Channel A sets the threshold current A, and channel B sets the threshold current B. When the motor rotates forward, comparator A outputs a 0-5V square wave, and comparator B outputs a low level. After recognizing the above signals, the MCU on the control board determines that the motor is rotating forward and calculates the number of square waves output by comparator A to determine the motor position and speed.

[0048] When the motor reverses, comparator B outputs a 0-5V square wave, and comparator A outputs a high level (1). After recognizing these signals, the MCU determines that the motor is reversing and calculates the number of square waves output by comparator B to determine the motor's position and speed.

[0049] If the MCU resources on the controller are sufficient, AD sampling analysis can also be used to separate the signal.

[0050] Example 2 differs from Example 1 in that: See [link to example 1] Figure 3 As shown, the two signals from the Hall sensor are inverted by Q1 and Q2 before being output, and the other principles are the same. Specifically, the voltage regulator circuit and the signal superposition circuit include a voltage regulator IC1, a first transistor Q1, and a second transistor Q2. The voltage regulator IC1 has a positive pin VIN, a regulated output pin OUT, and a negative pin GND. The positive pin VIN of the voltage regulator IC1 is electrically connected to the positive terminal J2 of the motor power supply and the negative terminal J5 of the motor speed control through the rectifier and filter circuit.

[0051] The negative pin GND of the voltage regulator IC1 is electrically connected to the ground transmission terminal J8; the Hall sensor U1 is a Hall sensor with direction U1, the voltage regulator output pin OUT of the voltage regulator IC1 is electrically connected to the collector of the first transistor Q1 and the collector of the second transistor Q2, the direction signal output pin and the speed signal output pin of the Hall sensor U1 are electrically connected to the base of the first transistor Q1 and the base of the second transistor Q2, respectively, and the emitters of the first transistor Q1 and the second transistor Q2 are electrically connected to the ground transmission terminal J8, so that the two currents generated by the direction signal output pin and the speed signal output pin are directly inverted by the first transistor Q1 and the second transistor Q2 and then output to the ground transmission terminal J8.

[0052] The voltage regulator IC1's regulated output pin OUT is also electrically connected to the Hall positive voltage terminal VCC of the Hall sensor U1 through a power isolation circuit.

[0053] The voltage regulator IC1 is a high-voltage regulator IC1, and the voltage output pin OUT provides a 5V output. The voltage output pin OUT is electrically connected to the collector of the first transistor Q1 and the collector of the second transistor Q2 through the first resistor R4 and the second resistor R3, respectively. The resistance values ​​of the first resistor R4 and the second resistor R3 are both 1K. The direction signal output pin and the speed signal output pin are electrically connected to the power isolation circuit through the third resistor R6 and the fourth resistor R5, respectively, as shown in the figure.

[0054] A diode D1 is also provided between the grounding transmission terminal J8 and the rectifier filter circuit. Diode D1 is a silicon rectifier diode (ordinary diode M7).

[0055] The first transistor Q1 and the second transistor Q2 are both model 4401.

[0056] A method for transmitting direction and speed signals of a three-wire DC motor is provided. A Hall sensor U1 is used to detect the multipole magnetic ring on the DC motor shaft. The power supply of the DC motor is regulated by a voltage regulator circuit and then used to supply power to the Hall sensor U1. The speed signal and direction signal of the Hall sensor U1 are superimposed and transmitted through the ground wire. At the same time, the ground wire is compatible with the anti-interference grounding of the DC motor, the static current of the voltage regulator circuit and the static current of the Hall sensor U1.

[0057] The speed and direction of the DC motor can be analyzed from the ground current signal using a dual-channel current comparator or an AD sampling circuit.

[0058] The above describes the preferred embodiments of the present invention, illustrating and describing the basic principles, main features, and advantages of the invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as defined by the appended claims and their equivalents.

Claims

1. A transmission circuit for the direction and speed signals of a three-wire DC motor, comprising a positive terminal for the motor power supply, a negative terminal for the motor speed control, and a grounding transmission terminal, characterized in that: It also includes a multi-pole magnetic ring mounted on the shaft of a DC motor and a Hall sensor driven by the multi-pole magnetic ring. The Hall sensor has a Hall positive voltage terminal, a direction signal output pin, a speed signal output pin, and a Hall ground terminal. The positive terminal of the motor power supply and the negative terminal of the motor speed control are electrically connected to the Hall positive voltage terminal through a rectifier filter circuit and a voltage regulator circuit. The ground transmission terminal is electrically connected to the Hall ground terminal. The direction signal output pin and the speed signal output pin are electrically connected to the Hall ground terminal indirectly or directly through a signal superposition circuit, so that the direction signal and speed signal generated by the Hall sensor are superimposed with the voltage regulator circuit and the static current of the Hall sensor and transmitted through the ground transmission terminal.

2. The transmission circuit for the direction and speed signals of a three-wire DC motor according to claim 1, characterized in that: The voltage regulator circuit and the signal superposition circuit include a voltage regulator, a first pull-up resistor and a second pull-up resistor. The voltage regulator has a positive pin, a voltage regulation output pin and a negative pin. The positive pin of the voltage regulator is electrically connected to the positive terminal of the motor power supply and the negative terminal of the motor speed control through the rectifier and filter circuit. The negative pin of the voltage regulator is electrically connected to the ground transmission terminal; the Hall sensor is an internally open-drain Hall sensor with direction, and the voltage regulator's regulated output pin is electrically connected to the speed signal output pin and direction signal output pin of the Hall sensor through a first pull-up resistor and a second pull-up resistor, respectively, so that the two currents generated by the speed signal output pin and the direction signal output pin can indirectly flow out to the ground transmission terminal through the Hall ground terminal; The voltage regulator's regulated output pin is also electrically connected to the Hall positive voltage terminal of the Hall sensor via a power isolation circuit.

3. The transmission circuit for the direction and speed signals of a three-wire DC motor according to claim 2, characterized in that: The voltage regulator is a high-voltage regulator, and the voltage regulator output pin provides a 5V output. The resistance values ​​of the first pull-up resistor and the second pull-up resistor are both 1K, so that the current amplification of the Hall ground terminal is 0mA or 5mA.

4. The transmission circuit for the direction and speed signals of a three-wire DC motor according to claim 1, characterized in that: The voltage regulator circuit and the signal superposition circuit include a voltage regulator, a first transistor and a second transistor. The voltage regulator has a positive pin, a voltage regulation output pin and a negative pin. The positive pin of the voltage regulator is electrically connected to the positive terminal of the motor power supply and the negative terminal of the motor speed control through the rectifier and filter circuit. The negative pin of the voltage regulator is electrically connected to the ground transmission terminal; the Hall sensor is a Hall sensor with direction, the voltage regulator's regulated output pin is electrically connected to the collector of the first transistor and the collector of the second transistor, the direction signal output pin and the speed signal output pin of the Hall sensor are electrically connected to the base of the first transistor and the base of the second transistor, respectively, and the emitters of the first transistor and the second transistor are electrically connected to the ground transmission terminal, so that the two currents generated by the direction signal output pin and the speed signal output pin are directly inverted by the first transistor and the second transistor and then output to the ground transmission terminal; The voltage regulator's regulated output pin is also electrically connected to the Hall positive voltage terminal of the Hall sensor via a power isolation circuit.

5. The transmission circuit for the direction and speed signals of a three-wire DC motor according to claim 4, characterized in that: The voltage regulator is a high-voltage regulator, and the voltage regulation output pin provides a 5V output. The voltage regulation output pin is electrically connected to the collector of the first transistor and the collector of the second transistor through a first resistor and a second resistor, respectively. The resistance values ​​of the first resistor and the second resistor are both 1K. The direction signal output pin and the speed signal output pin are electrically connected to the power isolation circuit through a third resistor and a fourth resistor, respectively.

6. The transmission circuit for the direction and speed signals of a three-wire DC motor according to any one of claims 2 to 5, characterized in that: The voltage regulator circuit also includes a voltage regulator protection circuit, which includes a unidirectional transient diode connected between the positive and negative terminals.

7. The transmission circuit for the direction and speed signals of a three-wire DC motor according to claim 1, characterized in that: The Hall sensor is mounted on a carbon brush plate, which has two carbon brush electrodes. The two carbon brush electrodes are electrically connected to the positive terminal of the motor power supply and the negative terminal of the motor speed control, respectively. The carbon brush plate is also equipped with a motor electromagnetic compatibility suppression device.

8. The transmission circuit for the direction and speed signals of a three-wire DC motor according to claim 7, characterized in that: A bidirectional transient diode is also provided between the two carbon brush electrodes.

9. A method for transmitting direction and speed signals of a three-wire DC motor according to claim 1, characterized in that: A Hall sensor is used to detect the multipole magnetic ring on the shaft of a DC motor. The power supply of the DC motor is regulated by a voltage regulator circuit and then used to power the Hall sensor. The speed signal and direction signal of the Hall sensor are superimposed and transmitted through the ground wire. At the same time, the ground wire is compatible with the anti-interference grounding of the DC motor, the static current of the voltage regulator circuit and the static current of the Hall sensor.

10. The method for transmitting the direction and speed signals of a three-wire DC motor according to claim 9, characterized in that: The speed and direction of the DC motor can be analyzed from the ground current signal using a dual-channel current comparator or an AD sampling circuit.

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