Direct current motor current detection and over-current protection drive circuit design method

Abstract

The invention discloses a direct current motor current detection and over-current protection drive circuit design method, and belongs to the field of electric control system circuit design. The circuit designed by the design method can monitor the over-current state of the direct current motor in real time, and when the direct current motor is in the over-current state, the drive circuit logic gate can actively lower the level of an output signal, so that the over-current protection function of the direct current motor is realized. Through the design of the DC motor current detection and over-current protection driving circuit, the current of a working loop of the DC motor can be detected, and meanwhile, components near the circuit and even the motor can be protected from being damaged under the conditions of overload, short circuit and the like of the DC motor, so that the driving circuit and the DC motor can be ensured to operate safely and stably.

Description

Technical Field

[0001] The present invention relates to the technical field of electric control system circuit design, and in particular to a method for designing a DC motor current detection and overcurrent protection drive circuit. Background Art

[0002] With the development of electric servo control, DC motors are increasingly used in the actuators of small UAV systems. Small and compact, DC motors primarily control the flight and attitude of the drone by controlling the current consumed by the driver, driving the DC motor to rotate the wings and adjust the rudder angles of the servo. Ideally, the load on a DC motor during operation should be between no-load and rated load, ensuring normal operation. However, unexpected situations, such as a short circuit in the DC motor's control drive circuit or a jammed actuator mechanism causing an abnormal overload, can cause the DC motor's operating circuit current to increase dramatically, potentially burning the motor. Over time, this can also damage the motor's peripheral components and the controller circuit board, posing a serious threat to the drone's flight safety.

[0003] Currently, the most common overcurrent protection method is to select high-voltage, surge-current-resistant components to prevent damage to the control driver due to short circuits or overloads. However, this method cannot effectively suppress the increase in current in the DC motor's operating circuit, and the motor may still burn out. Therefore, it is particularly important to design a DC motor current detection and overcurrent protection drive circuit to address the increase in operating circuit current caused by short circuits or overloads. Summary of the Invention

[0004] The present invention provides a method for designing a DC motor current detection and overcurrent protection drive circuit. In the circuit, an MCU main control chip can detect and collect the current value in the DC motor working circuit. At the same time, the current detection interval threshold can be adjusted by setting the resistance value of the current sampling resistor in the drive circuit. The circuit has the function of real-time monitoring of the DC motor overcurrent state. When the DC motor is in the overcurrent state, the drive circuit logic gate will actively lower the output signal level, thereby realizing the DC motor overcurrent protection function. Through this DC motor drive circuit design, not only can the DC motor operating current be detected, but also the components near the circuit and even the motor itself can be protected from damage in the event of DC motor overload, short circuit, etc., ensuring that the drive circuit and the DC motor can operate safely and stably.

[0005] An embodiment of the present invention provides a method for designing a DC motor current detection and overcurrent protection drive circuit, comprising the following steps:

[0006] Step 1: Determine the normal operating current range and supply voltage of the DC motor, select the current sampling resistor and the DC motor driver chip, connect the current sampling resistor in series in the current loop of the DC motor driver chip, and connect the two ends of the current sampling resistor to the V in+ pin and V in- Pins are connected to calculate the current sense amplifier output voltage;

[0007] Step 2: Set the positive input voltage V of the comparator inside the current sensing amplifier chip. cmp1+ and V cmp2+ , connect the current sense amplifier chip pin to V cmp1+ and V cmp2+ pins to connect the current sense amplifier output voltage As the positive input voltage of the comparator inside the current sense amplifier chip;

[0008] Step 3: Based on the normal operating current range of the DC motor, the working principle of the internal comparator of the current sense amplifier, and the logic gate input / output relationship, use a voltage divider circuit and configure multiple resistor values to set the reference voltage of the negative input terminal of the internal comparator of the current sense amplifier chip;

[0009] Step 4: Connect the logic gate input pins in1 and in2 to the current sensing amplifier chip output pins cmpout1 and cmpout2 respectively, connect the logic gate input pin in0 to the MCU main control chip control signal output pin, and connect the logic gate output pins Y1 and Y2 to the DC motor driver chip input pins IN1 and IN2 respectively. The current sensing amplifier output voltage The pin is connected to the A / D acquisition channel of the MCU main control chip to configure the power supply voltage of the circuit components.

[0010] Optionally, in one embodiment of the present invention, in step 1, according to the DC motor model, the normal operating current range A1-A2 of the motor and the supply voltage are determined, and the current sampling resistor R is selected. sense and DC motor driver chip, the current sampling resistor R sense Connect in series in the current loop of the DC motor driver chip, and connect the two ends of the current sampling resistor to the V in+ pin and V in- Pins are connected to calculate the current sense amplifier output voltage

[0011]

[0012] Among them, G is the amplification factor of the current sensing amplifier chip INA20x.

[0013] Optionally, in one embodiment of the present invention, in step 2, the positive input voltage V of the comparator inside the current sensing amplifier chip is set. cmp1+ and V cmp2+ , connect the current sense amplifier chip pin to V cmp1+ and V cmp2+ Pins connected, so

[0014] Optionally, in one embodiment of the present invention, in step 3, according to the normal operating current range A1-A2 of the DC motor and the working principle of the internal comparator of the current sensing amplifier and the input / output relationship of the logic gate, a voltage divider circuit is used to configure the resistance values of the resistors R1, R2, R3 and R4, and set the reference voltage V of the inverting input terminal of the internal comparator of the current sensing amplifier chip. ref1 and V ref2 , ensure V ref1 and V ref2 The setting value range meets V ref1 =A1×R sense ×G、V ref2 =A2×R sense ×G, where G is the amplification factor of the current sensing amplifier chip INA20x, is the current sense amplifier output voltage.

[0015] In the DC motor current detection and overcurrent protection drive circuit design method of the embodiment of the present invention, the MCU main control chip can detect and collect the current value in the DC motor working circuit, and at the same time, the current detection interval threshold can be adjusted by setting the resistance value of the current sampling resistor in the drive circuit. The circuit has the function of real-time monitoring of the overcurrent state of the DC motor. When the DC motor is in the overcurrent state, the drive circuit logic gate will actively lower the output signal level, thereby realizing the overcurrent protection function. Through this DC motor drive circuit design, not only can the DC motor working circuit current be detected, but also the components near the circuit and even the motor itself can be protected from damage when the DC motor is overloaded, short-circuited, etc., ensuring that the drive circuit and the DC motor can operate safely and stably.

[0016] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0018] Figure 1This is a flow chart of a method for designing a DC motor current detection and overcurrent protection drive circuit according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a DC motor current detection and overcurrent protection drive circuit design according to an embodiment of the present invention;

[0020] Figure 3 1 is a logic gate input / output relationship diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0022] like Figure 1 and Figure 2 As shown, the DC motor current detection and overcurrent protection drive circuit design method includes the following steps:

[0023] Step 1: Determine the normal operating current range A1-A2 and the supply voltage of the DC motor according to the DC motor model used; select the current sampling resistor R with appropriate power, resistance value, and sampling accuracy. sense And the DC motor driver chip, the current sampling resistor R sense Connect in series in the current loop of the DC motor driver chip, and connect the two ends of the current sampling resistor to the V in+ pin and V in- Pins are connected to calculate the current sense amplifier output voltage Where G is the amplification factor of the current sensing amplifier chip INA20x.

[0024] Step 2: Set the positive input voltage V of the comparator inside the current sense amplifier chip cmp1+ and V cmp2+ , the current sense amplifier chip Pin and V cmp1+ and V cmp2+ Pins connected, so The current sense amplifier output voltage Serves as the positive input voltage of the comparator inside the current sense amplifier chip.

[0025] Step 3: Based on the normal operating current range A1-A2 of the DC motor, the working principle of the internal comparator of the current sense amplifier, and the logic gate input / output relationship, use a voltage divider circuit to configure the resistance values of R1, R2, R3, and R4, and set the reference voltage V at the negative input terminal of the internal comparator of the current sense amplifier chip. ref1 and V ref2 , ensure V ref1 and V ref2 The setting value range meets V ref1 =A1×R sense ×G、V ref2 =A2×R sense ×G, where G is the amplification factor of the current sensing amplifier chip INA20x.

[0026] In step 3, the working principle of the comparator inside the current sensing amplifier is that when the comparator's positive input voltage is greater than the reverse input voltage, the comparator outputs a 5V high level, and when the comparator's positive input voltage is less than the reverse input voltage, the comparator outputs a 0V low level. Figure 3 In the logic gate input / output relationship table shown, when the in2 input is H (H represents a high level, generally 5V) and the in1 input is L (L represents a low level, generally 0V), the logic gate output Y1 / Y2 is always H; when the in2 input is H and the in1 input is H, the logic gate output Y1 / Y2 is always L. Based on the normal operating current range A1-A2 of the DC motor, the working principle of the internal comparator of the current sense amplifier, and the logic gate input / output relationship, a voltage divider circuit is used to configure the resistance values of R1, R2, R3, and R4, and set the reference voltage V at the inverting input terminal of the internal comparator of the current sense amplifier chip. ref1 and V ref2 , ensure V ref1 and V ref2 The setting value range meets V ref1 =A1×R sense ×G、V ref2 =A2×R sense ×G, where G is the amplification factor of the current sensing amplifier chip INA20x.

[0027] Step 4: Connect the logic gate input pins in1 and in2 to the current sensing amplifier chip output pins cmpout1 and cmpout2 respectively, connect the logic gate input pin in0 to the MCU main control chip control signal output pin, and connect the logic gate output pins Y1 and Y2 to the DC motor driver chip input pins IN1 and IN2 respectively. The current sensing amplifier output voltage The pins are connected to the A / D acquisition channel of the MCU main control chip, and the capacitors, resistors and power supply voltages of the circuit periphery are configured to complete the DC motor working current detection and overcurrent protection drive circuit design, which can realize the drive control of the DC motor, DC motor current detection and DC motor overcurrent protection.

[0028] In step 4, when the DC motor operating current A is within the range of A1 to A2, that is, V ref1 ≤V cmp1+ 、V ref2 ≥V cmp2+ cmpout1 outputs high level (in1 input high level), cmpout2 outputs low level (in2 input low level), at this time the motor works normally, the logic gate output signal Y1 / Y2 is consistent with the control signal 1 / 2 output by the MCU main control chip; when the DC motor working current A exceeds the working current upper limit A2, that is, V ref1 <V cmp1+ 、 cmpout1 outputs a high level (in1 input is high level), cmpout2 outputs a high level (in2 input is high level). At this time, the motor is in an overcurrent state, and the logic gate output signal Y1 / Y2 actively turns to a low level output to protect the motor itself and the peripheral components of the drive circuit.

[0029] According to the DC motor current detection and overcurrent protection drive circuit design method proposed in an embodiment of the present invention, this DC motor current detection and overcurrent protection drive circuit design protects nearby circuit components and even the motor itself from damage in the event of DC motor overload or short circuit, thereby ensuring that the drive circuit and DC motor can operate safely and stably.

[0030] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "N" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or N executable instructions for implementing a custom logical function or step of a process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

Claims

1. A method for designing a DC motor current detection and overcurrent protection drive circuit, characterized in that: The following steps are involved: Step 1: Determine the normal operating current range and supply voltage of the DC motor, select the current sampling resistor and the DC motor driver chip, connect the current sampling resistor in series in the current loop of the DC motor driver chip, and connect the two ends of the current sampling resistor to the V in+ pin and V in- Pins are connected to calculate the current sense amplifier output voltage; Step 2: Set the positive input voltage V of the comparator inside the current sensing amplifier chip. cmp1+ and V cmp2+ , connect the current sense amplifier chip pin to V cmp1+ and V cmp2+ pins to connect the current sense amplifier output voltage As the positive input voltage of the comparator inside the current sense amplifier chip; Step 3: Based on the normal operating current range of the DC motor, the working principle of the internal comparator of the current sense amplifier, and the logic gate input / output relationship, use a voltage divider circuit and configure multiple resistor values to set the reference voltage at the negative input terminal of the internal comparator of the current sense amplifier chip; Step 4: Connect the logic gate input pins in1 and in2 to the current sensing amplifier chip output pins cmpout1 and cmpout2 respectively, connect the logic gate input pin in0 to the MCU main control chip control signal output pin, and connect the logic gate output pins Y1 and Y2 to the DC motor driver chip input pins IN1 and IN2 respectively. The current sensing amplifier output voltage The pin is connected to the A / D acquisition channel of the MCU main control chip to configure the power supply voltage of the circuit components.

2. The method according to claim 1, characterized in that In step 1, according to the DC motor model, determine the normal operating current range A1~A2 and the supply voltage of the motor, and select the current sampling resistor R sense and DC motor driver chip, the current sampling resistor R sense Connect in series in the current loop of the DC motor driver chip, and connect the two ends of the current sampling resistor to the V in+ pin and V in- Pins are connected to calculate the current sense amplifier output voltage Among them, G is the amplification factor of the current sensing amplifier chip INA20x.

3. The method according to claim 1, characterized in that In step 2, set the positive input voltage V of the comparator inside the current sense amplifier chip. cmp1+ and V cmp2+ , connect the current sense amplifier chip pin to V cmp1+ and V cmp2+ Pins connected, so 4. The method according to claim 1, wherein In step 3, according to the normal working current range A1-A2 of the DC motor and the working principle of the internal comparator of the current sensing amplifier and the input / output relationship of the logic gate, a voltage divider circuit is used to configure the resistance values of resistors R1, R2, R3 and R4, and set the reference voltage V at the negative input terminal of the internal comparator of the current sensing amplifier chip. ref1 and V ref2 , ensure V ref1 and V ref2 The setting value range meets V ref1 =A1×R sense ×G、V ref2 =A2×R sense ×G, where G is the amplification factor of the current sensing amplifier chip INA20x, is the current sense amplifier output voltage.

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