Circuit applied to configurable over-current protection latch function in motor drive

Abstract

The application is applied to the circuit of configurable over-current protection latch function in motor drive, input port IN1 is connected with the emitter of PNP triode Q1; one end of R5 is connected with the collector of Q1, and the other end is connected with the base of NPN triode Q2; one end of R7 is connected with the base of Q2; one end of R4 is connected with the base of Q1, and the other end is connected with the collector of Q2; one end of configuration jumper terminal J1 is connected with the collector of Q2, and the other end is connected with the gate of M1; the anode of D1 is connected with VCC after being connected with R6 in series, and the cathode of D1 is connected with the gate of NMOS M1; input port IN2 is connected with the gate of M1; the fourth pin of photoelectric coupler V1 is connected with VCC after being connected with R1 in series, the second pin of V1 is connected with the drain of M1, and the first pin of V1 is connected with IN1 after being connected with R3 in series; one end of R2 is connected with IN1; output port OUT1 is connected with the fourth pin of V1. The application configures whether the over-current protection signal has latch function through the jumper.

Description

Technical Field

[0001] This invention relates to the field of current detection, and more specifically to a circuit with configurable overcurrent protection latching function applied in motor drives. Background Technology

[0002] Currently, most motor drivers are designed with motor overcurrent detection circuits. Due to cost and size considerations, the overcurrent protection design typically uses "low-end" detection. This involves connecting one or more parallel power resistors in series between the source of the switching transistor in an H-bridge or three-phase bridge and the reference ground as current sampling resistors. The resistance value is adjusted according to the current flowing through the motor windings, and is generally below 1 ohm. When the voltage across the resistor exceeds a set threshold, an overcurrent is considered to have occurred. Subsequently, a hardware comparator or MCU (Microcontroller Unit) processor sends a protection signal to the power driver's hardware circuitry. This disables the driver chip or quickly shuts down the upper and lower bridge arm switches, preventing excessive current from damaging or burning out the power switches, thus protecting the motor and its drive circuitry.

[0003] However, this overcurrent protection has certain drawbacks. It can only simply determine whether there is an overcurrent. When the motor is under abnormal operating conditions, such as internal motor faults, motor stall, unreasonable servo motor control parameters, or motor control program malfunction, the current value fluctuates around the overcurrent setting threshold. Because the hardware protection circuit responds very quickly, the controlled motor and its drive circuit switching transistors will be repeatedly subjected to large current impacts in the "overcurrent" and "no-overcurrent" states. Especially at high frequencies, the tiny vibrations at the motor end are not easy to observe. If the motor is subjected to such frequent impacts for a long time, it may cause the motor drive circuit to burn out, the motor performance to degrade, or permanent damage. Summary of the Invention

[0004] The purpose of this invention is to provide a circuit with configurable overcurrent protection latch function for use in motor drives. The overcurrent protection latch function can be freely configured to be added via jumpers. Adding the overcurrent protection latch function can solve the problem of frequent energy impacts of large current on the motor and its drive circuit under abnormal overcurrent conditions, thereby improving the reliability of the original motor overcurrent protection circuit.

[0005] To achieve the above objectives, this invention provides a circuit with configurable overcurrent protection latching function for use in motor drives, comprising an optocoupler V1, an NMOS transistor M1, a PNP transistor Q1, an NPN transistor Q2, a light-emitting diode D1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a jumper terminal J1, a first input port IN1, a second input port IN2, and an output port OUT1; the first input port IN1 is connected to the emitter of the PNP transistor Q1; one end of the fifth resistor R5 is connected to the collector of the PNP transistor Q1, and the other end is connected to the base of the NPN transistor Q2; one end of the seventh resistor R7 is connected to the base of the NPN transistor Q2, and the other end is connected to reference ground; the emitter of the NPN transistor Q2 is connected to reference ground; one end of the fourth resistor R4 is connected to the base of the PNP transistor Q1. One end is connected to the collector of NPN transistor Q2; one end of jumper terminal J1 is connected to the collector of NPN transistor Q2, and the other end is connected to the gate of NMOS transistor M1; the anode of LED D1 is connected to the power supply VCC after being connected in series with the sixth resistor R6, and the cathode of LED D1 is connected to the gate of NMOS transistor M1; the second input port IN2 is connected to the gate of NMOS transistor M1; the fourth pin of optocoupler V1 is connected to the power supply VCC after being connected in series with the first resistor R1, the third pin of optocoupler V1 is connected to the reference ground, the second pin of optocoupler V1 is connected to the drain of NMOS transistor M1, the first pin of optocoupler V1 is connected to the first input port IN1 after being connected in series with the third resistor R3; one end of the second resistor R2 is connected to the reference ground, and the other end is connected to the first input port IN1; the source of NMOS transistor M1 is connected to the reference ground; the output port OUT1 is connected to the fourth pin of optocoupler V1.

[0006] The circuit described above, which is configurable for overcurrent protection latching in motor drives, uses a totem-output type high-speed optocoupler, specifically the optocoupler V1.

[0007] The circuit described above, which is configurable for overcurrent protection latching in motor drives, uses transistor arrays for both PNP transistor Q1 and NPN transistor Q2.

[0008] The circuit described above, which is configurable for overcurrent protection latching in motor drives, uses an NMOS transistor M1 with a low on-threshold value of 2V-4V.

[0009] The circuit described above, which is configurable for overcurrent protection latching in motor drives, inputs the original input control signal of the motor drive through the first input port IN1, inputs the overcurrent detection input control signal through the second input port IN2, and outputs the motor drive output control signal configured with latching function through the output port OUT1.

[0010] The circuit described above, which is configurable for overcurrent protection latching in motor drives, configures the latching function by using a jumper terminal J1. When the jumper is connected, the control signal output from the output port OUT1 has a latching function; when the jumper is not connected, the control signal output from the output port OUT1 does not have a latching function.

[0011] Compared with the prior art, the beneficial technical effects of the present invention are:

[0012] (1) The entire protection scheme is implemented in hardware, requiring only 3 external ports, which takes up a small volume and can be matched with most motor "low-end" overcurrent protection circuits.

[0013] (2) Equipped with an overcurrent indicator light, which can show the overcurrent fault condition immediately;

[0014] (3) The overcurrent protection latch function can be freely configured via jumpers without affecting the original overcurrent protection circuit design, making it simple to implement;

[0015] (4) Adding a latching function can solve the problem of frequent energy impacts of large current on the motor and its drive circuit under abnormal overcurrent conditions, and at the same time improve the reliability of the original motor overcurrent protection circuit. Attached Figure Description

[0016] The circuit of the present invention, which is configurable for overcurrent protection latching in motor drives, is given in the following embodiments and figures.

[0017] Figure 1 This is a schematic diagram of a circuit with configurable overcurrent protection latch function applied in a motor drive according to a preferred embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the circuit with configurable overcurrent protection latch function applied in a motor drive according to a preferred embodiment of the present invention. Detailed Implementation

[0019] The following will combine Figures 1-2 The circuit of the present invention, which is configurable for overcurrent protection latching function in motor drive, is described in further detail.

[0020] Figure 1 The diagram shown is a schematic of a circuit with configurable overcurrent protection latch function applied in a motor drive according to a preferred embodiment of the present invention.

[0021] See Figure 1 The circuit in this embodiment, which is configured to provide overcurrent protection latching function in motor drive, has two input ports (IN1 and IN2) and one output port (OUT1).

[0022] The circuit in this embodiment, which is configured to provide overcurrent protection latching function in motor drive, includes an optocoupler V1, an NMOS transistor M1, a PNP transistor Q1, an NPN transistor Q2, a light-emitting diode D1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a configuration jumper terminal J1.

[0023] The first input port IN1 is connected to the emitter of the PNP transistor Q1;

[0024] One end of the fifth resistor R5 is connected to the collector of PNP transistor Q1, and the other end is connected to the base of NPN transistor Q2;

[0025] One end of the seventh resistor R7 is connected to the base of the NPN transistor Q2, and the other end is connected to the reference ground;

[0026] The emitter of NPN transistor Q2 is connected to reference ground;

[0027] One end of the fourth resistor R4 is connected to the base of the PNP transistor Q1, and the other end is connected to the collector of the NPN transistor Q2.

[0028] One end of jumper terminal J1 is connected to the collector of NPN transistor Q2, and the other end is connected to the gate of NMOS transistor M1;

[0029] The anode of LED D1 is connected to the power supply VCC via a series resistor R6, and the cathode of LED D1 is connected to the gate of NMOS transistor M1.

[0030] The second input port IN2 is connected to the gate of NMOS transistor M1;

[0031] The fourth pin of optocoupler V1 is connected to the power supply VCC after being connected in series with the first resistor R1. The third pin of optocoupler V1 is connected to the reference ground. The second pin of optocoupler V1 is connected to the drain of NMOS transistor M1. The first pin of optocoupler V1 is connected to the first input port IN1 after being connected in series with the third resistor R3.

[0032] One end of the second resistor R2 is connected to the reference ground, and the other end is connected to the first input port IN1.

[0033] The source of NMOS transistor M1 is connected to reference ground;

[0034] The output port OUT1 is connected to pin 4 of optocoupler V1.

[0035] The original input control signal for motor drive is input through the first input port IN1, the overcurrent detection input control signal is input through the second input port IN2, and the output control signal for motor drive after configuring latching function is output through the output port OUT1.

[0036] The light-emitting diode D1 is used to indicate whether there is an overcurrent, and an LED can be used. The second resistor R2 is a current-limiting resistor. Specifically, in this embodiment, the second resistor R2 is 1kΩ, and the light-emitting diode D1 is SZYY0603R.

[0037] The optocoupler V1 can be a totem output type high-speed optocoupler; specifically, in this embodiment, the EL357N is selected.

[0038] PNP transistor Q1 and NPN transistor Q2 are a transistor array, specifically, in this embodiment, a 2N4854.

[0039] In this embodiment, the NMOS transistor M1 is a MOS transistor with a low on-threshold (2V-4V).

[0040] Figure 2 The diagram shown is an application schematic of a circuit with configurable overcurrent protection latch function in a motor drive, according to a preferred embodiment of the present invention.

[0041] See Figure 2 In this embodiment, the output port OUT1 of the circuit 2, which is configured with overcurrent protection latching function in motor drive, is connected to the SD terminal of the motor drive module 3, and its first input port IN1 and second input port IN2 are connected to the MCU processor module 1; the motor drive module 3 is connected to the MCU processor module 1, the current sampling and amplification module 5, and the motor 4; the current sampling and amplification module 5 is connected to the AD conversion module 6, and the AD conversion module 6 is connected to the MCU processor module 1.

[0042] The MCU processor module 1 can be a microcontroller, DSP or FPGA chip. The first input port IN1 and the second input port IN2 of this circuit are connected to the general I / O of the MCU processor module 1.

[0043] In this circuit, jumper terminal J1 is configured to implement latching function. When the jumper is connected, the output control signal has latching function. When the jumper is not connected, the original overcurrent control strategy is not affected.

[0044] See Figure 2 The circuit with configurable overcurrent protection latch function applied in motor drive in this embodiment operates as follows:

[0045] The overcurrent protection circuit has two main input signals: one is the control shutdown signal CTRL_SD connected to the IN1 terminal by the MCU, and the other is the overcurrent detection signal OVC connected to the IN2 terminal. It also has an output signal SD_OUT (pull-up by default) used to control the switching of the motor drive module 3. When SD_OUT is high, the motor drive module 3 is turned off; when SD_OUT is low, the motor drive module 3 is enabled.

[0046] When no overcurrent occurs, OVC outputs a high level and CTRL_SD is high. At this time, NMOS transistor M1 and optocoupler V1, and when SD_OUT is low, motor drive module 3 is enabled and the circuit works normally.

[0047] When an overcurrent occurs, the OVC output goes low, the overcurrent indicator D2 lights up, the NMOS transistor M1 and optocoupler V1 are turned off, SD_OUT is pulled up to a high level, and the motor drive module 3 is turned off.

[0048] When jumper terminal J1 is not connected, the self-locking function does not work. That is, when an overcurrent occurs, the motor drive module 3 shuts down, the current drops below the protection point, and the motor drive module 3 continues to work, which is the periodic overcurrent protection.

[0049] When jumper terminal J1 is connected, this circuit automatically locks the overcurrent detection signal OVC to a low level, the overcurrent detection function no longer works, and the motor drive module 3 remains off until this circuit is reset, i.e., CTRL_SD is low, at which point the latching function is enabled.

[0050] The circuit of this invention, which can be configured with overcurrent protection latching function in motor drive, has a small footprint, is easy to observe faults, and has good application compatibility (it can be adapted to more than 95% of the "low-end" overcurrent protection circuits of motors). After adding the overcurrent protection latching function, it can solve the problem of frequent energy impacts of large current on the motor and its drive circuit under abnormal overcurrent conditions in the original motor overcurrent protection circuit, and at the same time improve the reliability of the original motor overcurrent protection circuit.

[0051] The specific embodiments of the present invention have demonstrated the features and progress of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the principle of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A circuit for configurable overcurrent protection latch function in motor drive, characterized in that, Includes optocoupler V1, NMOS transistor M1, PNP transistor Q1, NPN transistor Q2, light-emitting diode D1, first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, fifth resistor R5, sixth resistor R6, seventh resistor R7, configuration jumper terminal J1, first input port IN1, second input port IN2 and output port OUT1; The first input port IN1 is connected to the emitter of the PNP transistor Q1; One end of the fifth resistor R5 is connected to the collector of PNP transistor Q1, and the other end is connected to the base of NPN transistor Q2; One end of the seventh resistor R7 is connected to the base of the NPN transistor Q2, and the other end is connected to the reference ground; The emitter of NPN transistor Q2 is connected to reference ground; One end of the fourth resistor R4 is connected to the base of the PNP transistor Q1, and the other end is connected to the collector of the NPN transistor Q2. One end of jumper terminal J1 is connected to the collector of NPN transistor Q2, and the other end is connected to the gate of NMOS transistor M1; The anode of LED D1 is connected to the power supply VCC via a series resistor R6, and the cathode of LED D1 is connected to the gate of NMOS transistor M1. The second input port IN2 is connected to the gate of NMOS transistor M1; The fourth pin of optocoupler V1 is connected to the power supply VCC after being connected in series with the first resistor R1. The third pin of optocoupler V1 is connected to the reference ground. The second pin of optocoupler V1 is connected to the drain of NMOS transistor M1. The first pin of optocoupler V1 is connected to the first input port IN1 after being connected in series with the third resistor R3. One end of the second resistor R2 is connected to the reference ground, and the other end is connected to the first input port IN1. The source of NMOS transistor M1 is connected to reference ground; The output port OUT1 is connected to pin 4 of optocoupler V1.

2. The circuit with configurable overcurrent protection latching function applied in motor drive as described in claim 1, characterized in that, The optocoupler V1 adopts a totem output type high-speed optocoupler.

3. The circuit with configurable overcurrent protection latching function applied in motor drive as described in claim 1, characterized in that, Both PNP transistor Q1 and NPN transistor Q2 use transistor arrays.

4. The circuit with configurable overcurrent protection latching function applied in motor drive as described in claim 1, characterized in that, NMOS transistor M1 is a low on-threshold MOS transistor, which is 2V-4V.

5. The circuit with configurable overcurrent protection latching function applied in motor drive as described in claim 1, characterized in that, The original input control signal for motor drive is input through the first input port IN1, the overcurrent detection input control signal is input through the second input port IN2, and the output control signal for motor drive after configuring latching function is output through the output port OUT1.

6. The circuit with configurable overcurrent protection latching function applied in motor drive as described in claim 1, characterized in that, Configure jumper terminal J1 to implement latching function. When the jumper is connected, the control signal output from output port OUT1 has latching function. When the jumper is not connected, the control signal output from output port OUT1 does not have latching function.

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