Safety torque off circuit, control method and device of safety torque off circuit

Abstract

The application discloses a safe torque-off circuit, a control method and device of the safe torque-off circuit. The method comprises the following steps: after determining that a first isolation photocoupler receives a safe-off signal, a second diode is controlled to be cut off; the potential of the gate of an electronic switch device is pulled up to the voltage of a secondary side power supply through a fifth resistor, so as to control the electronic switch device to be cut off, thereby cutting off the secondary side power supply from driving the secondary side of the photocoupler; the voltage of an output pin is pulled down to the ground potential of the secondary side of the photocoupler through the photocoupler; and when the voltage between the gate and the source of a power switch device is detected to be lower than a conduction threshold, the power switch device is controlled to be cut off. The application solves the technical problems of poor real-time performance of the safe torque-off circuit in the related art due to the dependence on software response, and high cost and large size of the relay scheme.

Description

Technical Field

[0001] This invention relates to the field of industrial safety control technology, and more specifically, to a safety torque shutdown circuit, a control method for the safety torque shutdown circuit, and a device for such a circuit. Background Technology

[0002] In multi-axis servo drives, Safe Torque Off (STO) is a core function for ensuring equipment and personnel safety. It requires the system to reliably cut off motor torque upon receiving a safety request, and this process must meet the high safety integrity requirements for pure hardware shutdown. However, existing ST implementations suffer from two main drawbacks: First, they use safety relays or independent isolation power supplies to directly cut off the PWM signal or gate power, requiring each axis in a multi-axis system to have an independent safety component, resulting in bulky components, high costs, and difficulty in achieving precise inter-axis fault isolation. Second, they rely on microcontroller (MCU) software to respond to drive optocoupler fault signals to stop PWM output. This approach involves software execution, which carries the risk of interruption delays or program crashes, failing to meet the stringent functional safety standards for reliable hardware-level shutdown.

[0003] In addition, existing solutions often fail to make full use of the inherent undervoltage lockout (UVLO) mechanism inside the drive optocoupler, treating it only as a passive power supply anomaly protection, rather than actively incorporating it into the execution and closed-loop diagnostic path of STO.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This invention provides a safe torque shutdown circuit, a control method for the safe torque shutdown circuit, and an apparatus for controlling the safe torque shutdown circuit, in order to at least solve the technical problems in the related art where the safe torque shutdown circuit has poor real-time performance due to its reliance on software response, and where the relay solution has high cost and large size.

[0006] According to one aspect of the present invention, a safe torque shutdown circuit is provided, comprising: a driving unit including a driving optocoupler and a power switching device, wherein the gate of the power switching device is connected to the output pin of the driving optocoupler, and the driving optocoupler converts an input signal from a microcontroller into a driving signal to drive the power switching device to turn on or off; a switching unit including an electronic switching device and a first isolation optocoupler, wherein the gate of the electronic switching device is connected to the collector of the first isolation optocoupler, the drain of the electronic switching device is connected to the positive power supply pin of the driving optocoupler, and the source of the electronic switching device is connected to the secondary power supply, wherein the first isolation optocoupler controls the electronic switching device to turn off to cut off the secondary power supply when receiving a safe shutdown signal; and a feedback unit including a comparator and a second isolation optocoupler, wherein the output terminal of the comparator is connected to the cathode of the light-emitting diode of the second isolation optocoupler, and the feedback unit sends a fault signal to the microcontroller through the second isolation optocoupler when the secondary voltage of the driving optocoupler is less than an undervoltage threshold voltage.

[0007] Optionally, the driving optocoupler includes primary-side pins, which include a power supply pin, a ground pin, a fault output pin, a positive input pin, and a negative input pin. The driving unit includes: a driving and fault detection module, including a first resistor, a first capacitor, and a primary-side power supply; the power supply pin is connected to the primary-side power supply; one end of the first resistor is connected to the primary-side power supply; the other end of the first resistor is connected to the fault output pin; one end of the first capacitor is connected to the primary-side power supply; the other end of the first capacitor is grounded and connected to the ground pin; the fault output pin is externally connected to the microcontroller to send a fault alarm signal to the microcontroller; and a driving signal input module, where the positive input pin receives the positive input signal output by the microcontroller, and the negative input pin receives the negative input signal output by the microcontroller.

[0008] Optionally, the driving optocoupler includes secondary pins, which include the output pin, auxiliary output pin, overvoltage protection pin, negative power supply pin, and positive power supply pin. The driving unit includes: an overvoltage protection module, including a second resistor and a first diode, one end of the second resistor being connected to the overvoltage protection pin, the other end of the second resistor being connected to the anode of the first diode, and the cathode of the first diode being connected to the bus voltage; a driving and protection module, including a third resistor, a fourth resistor, a third capacitor, and the power switching device, one end of the third resistor being connected to the output pin, the other end of the third resistor being connected to the gate of the power switching device, the fourth resistor and the third capacitor being connected in parallel between the gate and emitter of the power switching device, and the auxiliary output pin being connected to the gate of the power switching device; and a ground reference module, including a second capacitor, the negative power supply pin being grounded, one end of the second capacitor being grounded, and the other end of the second capacitor being connected to the positive power supply pin.

[0009] Optionally, the switching unit includes: a primary-side control module, comprising a second diode of the first isolation optocoupler, a sixth resistor, and a control power supply, wherein the anode of the second diode is connected to the input terminal of the safety shutdown signal and is connected to the control power supply through the sixth resistor, and the cathode of the second diode is grounded; and a secondary-side drive module, comprising a first transistor of the first isolation optocoupler, a fifth resistor, the electronic switching device, and the secondary-side power supply, wherein the emitter of the first transistor is grounded, the collector of the first transistor is connected to the gate of the electronic switching device, and is connected to the secondary-side power supply through the fifth resistor.

[0010] Optionally, the feedback unit includes: a voltage comparison module, comprising the comparator and a voltage divider module, wherein the non-inverting input of the comparator is connected to the drain of the electronic switching device, and the inverting input of the comparator is connected to the voltage divider circuit, the voltage divider circuit being used to divide the voltage of the secondary power supply to the undervoltage threshold voltage; and a signal isolation module, comprising the light-emitting diode of the second isolation optocoupler, the second transistor of the second isolation optocoupler, a ninth resistor, a tenth resistor, the primary power supply, and the secondary power supply, wherein the anode of the light-emitting diode is connected to the secondary power supply through the ninth resistor, the emitter of the second transistor is grounded, the collector of the second transistor is connected to the fault detection pin of the microcontroller and connected to one end of the tenth resistor, and the other end of the tenth resistor is connected to the primary power supply.

[0011] Optionally, the voltage divider submodule includes: a seventh resistor and an eighth resistor connected in series, the inverting input of the comparator being connected to the connection node of the seventh resistor and the eighth resistor, and the other end of the eighth resistor being grounded; and a secondary power supply, with the other end of the seventh resistor connected to the secondary power supply.

[0012] According to another aspect of the present invention, a control method for a safe torque turn-off circuit is also provided, applied to the safe torque turn-off circuit described in any one of the above embodiments, comprising: after determining that the first isolation optocoupler receives the safe turn-off signal, controlling the second diode to turn off; pulling up the potential of the gate of the electronic switching device to the voltage of the secondary power supply through the fifth resistor, thereby controlling the electronic switching device to turn off, thereby cutting off the power supply from the secondary power supply to the secondary side of the driving optocoupler; pulling down the voltage of the output pin to the secondary side ground potential of the driving optocoupler through the driving optocoupler; and controlling the power switching device to turn off when it is detected that the voltage between the gate and source of the power switching device is lower than the conduction threshold.

[0013] Optionally, the method further includes: when the comparator detects that the secondary side voltage of the driving optocoupler is less than or equal to the undervoltage threshold voltage, controlling the second isolation optocoupler to turn on; sending the fault signal to the microcontroller through the second isolation optocoupler to stop the microcontroller from sending input signals to the primary side input pin of the driving optocoupler.

[0014] According to another aspect of the present invention, a control device for a safe torque shutdown circuit is also provided, and a control method for the safe torque shutdown circuit described above is applied, comprising: a first control unit, configured to control the second diode to turn off after determining that the first isolation optocoupler receives the safe shutdown signal; a second control unit, configured to pull up the potential of the gate of the electronic switching device to the voltage of the secondary power supply through the fifth resistor, so as to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary power supply to the secondary side of the driving optocoupler; a pull-down unit, configured to pull down the voltage of the output pin to the secondary side ground potential of the driving optocoupler through the driving optocoupler; and a third control unit, configured to control the power switching device to turn off when it is detected that the voltage between the gate and source of the power switching device is lower than the conduction threshold.

[0015] Optionally, the control device of the safety torque shutdown circuit further includes: a fourth control unit, used to control the second isolation optocoupler to turn on when the comparator detects that the secondary side voltage of the driving optocoupler is less than or equal to the undervoltage threshold voltage; and a stop unit, used to send the fault signal to the microcontroller through the second isolation optocoupler to stop the microcontroller from sending input signals to the primary side input pin of the driving optocoupler.

[0016] According to one aspect of the present invention, a multi-axis servo driver is provided, the multi-axis servo driver using the control method of the safe torque shutdown circuit described in any one of the above embodiments.

[0017] According to one aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein the program executes the control method for the safe torque shutdown circuit described in any one of the preceding embodiments.

[0018] According to one aspect of the present invention, a processor is provided for running a program, wherein the program executes the control method for the safe torque shutdown circuit described in any one of the above embodiments.

[0019] According to one aspect of the present invention, a computer program product is provided, including computer instructions that, when executed by a processor, perform a control method for a safe torque shutdown circuit as described above.

[0020] By applying the technical solution of this application, in the control method of the above-mentioned safe torque turn-off circuit, after determining that the first isolation optocoupler receives the safe turn-off signal (STO signal), the second diode is controlled to turn off; the potential of the gate of the electronic switching device is pulled up to the voltage of the secondary power supply through the fifth resistor to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary side to the secondary side of the driving optocoupler; the voltage of the output pin is pulled down to the ground potential of the secondary side of the driving optocoupler through the driving optocoupler; when it is detected that the voltage between the gate and source of the power switching device is lower than the conduction threshold, the power switching device is controlled to turn off. This realizes the cutting off of the secondary power supply of the driving optocoupler by controlling the P-channel MOSFET through the isolation optocoupler, and the safe turn-off of the IGBT is achieved by forcibly pulling down the gate drive voltage using the undervoltage lockout (UVLO) hardware mechanism inside the driving optocoupler. The fault status is reported to the MCU in real time through an independent diagnostic feedback circuit. This solves the technical problems of poor real-time performance of the safe torque turn-off circuit due to reliance on software response and the high cost and large size of the relay solution in the related technology. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 This is a schematic diagram of a safe torque shutdown circuit according to an embodiment of the present invention;

[0023] Figure 2This is an STO circuit based on drive optocoupler power supply cutoff for a multi-axis servo driver according to an embodiment of the present invention;

[0024] Figure 3 This is a flowchart of a control method for a safe torque shutdown circuit according to an embodiment of the present invention;

[0025] Figure 4 This is a block diagram of an STO circuit based on the power cut-off of a drive optocoupler for a multi-axis servo driver according to an embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram of the control device for the safe torque shutdown circuit according to an embodiment of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] The following specific embodiments will provide a detailed description of the safe torque shutdown circuit, the control method for the safe torque shutdown circuit, and the device provided in the embodiments of the present invention.

[0030] According to one aspect of the present invention, a safe torque shutdown circuit is provided. Figure 1 This is a schematic diagram of a safe torque shutdown circuit according to an embodiment of the present invention, as shown below. Figure 1 As shown, the circuit includes: a driving unit 11, a switching unit 13, and a feedback unit 15, wherein,

[0031] The driving unit 11 includes a driving optocoupler and a power switching device. The gate of the power switching device is connected to the output pin of the driving optocoupler, and is used to drive the optocoupler to convert the input signal from the microcontroller into a driving signal to drive the power switching device to turn on or off.

[0032] The switching unit 13 includes an electronic switching device and a first isolation optocoupler. The gate of the electronic switching device is connected to the collector of the first isolation optocoupler, the drain of the electronic switching device is connected to the positive power supply pin of the driving optocoupler, and the source of the electronic switching device is connected to the secondary power supply. When the first isolation optocoupler receives a safety shutdown signal, it controls the electronic switching device to turn off to cut off the power supply to the secondary power supply.

[0033] Feedback unit 15 includes a comparator and a second isolation optocoupler. The output of the comparator is connected to the cathode of the light-emitting diode of the second isolation optocoupler. It is used to send a fault signal to the microcontroller through the second isolation optocoupler when the secondary voltage of the driving optocoupler is less than the undervoltage threshold voltage.

[0034] As described above, in this embodiment, after the first isolation optocoupler receives the safety turn-off signal, it controls the second diode to turn off; the potential of the gate of the electronic switching device is pulled up to the voltage of the secondary power supply through the fifth resistor to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary side to the secondary side of the driving optocoupler; the voltage of the output pin is pulled down to the ground potential of the secondary side of the driving optocoupler through the driving optocoupler; when the voltage between the gate and source of the power switching device is detected to be lower than the conduction threshold, the power switching device is controlled to turn off. This achieves the purpose of cutting off the power supply to the secondary side of the driving optocoupler by controlling the P-channel MOSFET through the isolation optocoupler, forcibly pulling down the gate drive voltage using the undervoltage lockout (UVLO) hardware mechanism inside the driving optocoupler to achieve the safe turn-off of the IGBT, and reporting the fault status to the MCU in real time through an independent diagnostic feedback circuit. This achieves the technical effect of high real-time performance, high reliability, and safe torque turn-off without MCU software intervention, significantly reducing the hardware cost and size of the multi-axis system, and possessing excellent inter-axis fault isolation capability.

[0035] Therefore, the technical solution provided by the above embodiments of the present invention solves the technical problems of poor real-time performance of the safety torque shutdown circuit due to reliance on software response, and the high cost and large size of the relay solution in the related art.

[0036] As an optional embodiment, the driving optocoupler includes primary-side pins, which include a power supply pin, a ground pin, a fault output pin, a positive input pin, and a negative input pin. The driving unit includes: a driving and fault detection module, which includes a first resistor, a first capacitor, and a primary-side power supply. The power supply pin is connected to the primary-side power supply. One end of the first resistor is connected to the primary-side power supply, and the other end of the first resistor is connected to the fault output pin. One end of the first capacitor is connected to the primary-side power supply, and the other end of the first capacitor is grounded and connected to the ground pin. The fault output pin is externally connected to a microcontroller to send a fault alarm signal to the microcontroller. The driving signal input module has a positive input pin that receives a positive input signal output by the microcontroller, and a negative input pin that receives an inverted input signal output by the microcontroller.

[0037] It should be noted that, Figure 2 This is an STO circuit based on drive optocoupler power supply disconnection for a multi-axis servo driver according to an embodiment of the present invention, such as... Figure 2 As shown, It is a resistor; It is a capacitor; It is a diode; It is an IGBT; It is a P-channel enhancement-mode MOSFET (hereinafter referred to as an electronic switching device). It drives the optocoupler; It is an isolation optocoupler; It is a comparator. , , and The drive circuit unit that constitutes one phase upper bridge arm of the motor is responsible for switching the IGBT on and off.

[0038] In this embodiment, the driving optocoupler Power supply pins (such as) Figure 2 Pin 2 shown: Connect to the primary power supply. Its grounding pin (such as Figure 2 Pin 1 shown: And pin 4: Connect to the original edge First capacitor Used for filtering the primary power supply. Drives the optocoupler. Fault output pin (such as Figure 2 Pin 3 (FAULT) is connected to an external microcontroller (MCU) to send the fault alarm signal DRV_FAULT; the first resistor One end is connected to the primary power supply. The other end is connected to the fault output pin, pulling the DRV_FAULT signal high; this configuration allows the drive optocoupler to... When an internal fault occurs, the fault output pin outputs a low level (signal DRV_FAULT is set to 0), while the first resistor... Ensure the fault output pin remains high (DRV_FAULT signal set to 1) upon power-up to prevent false alarms from the optocoupler driver. In the drive signal input module, the optocoupler driver... positive input pin (e.g.) Figure 2 Pins 6 (ANOOE) and 7 (ANOOE) shown receive the non-inverting input signal DRV_P from the microcontroller, and the inverting input pin (as shown) receives the non-inverting input signal DRV_P from the microcontroller. Figure 2 Pins 5 (CATHOOE) and 8 (CATHOOE) shown receive the inverted input signal DRV_N from the microcontroller to control the logic state inside the drive optocoupler.

[0039] As an optional embodiment, the driving optocoupler includes secondary pins, which include an output pin, an auxiliary output pin, an overvoltage protection pin, a negative power supply pin, and a positive power supply pin. The driving unit includes: an overvoltage protection module, including a second resistor and a first diode, one end of the second resistor being connected to the overvoltage protection pin, the other end of the second resistor being connected to the anode of the first diode, and the cathode of the first diode being connected to the bus voltage; a driving and protection module, including a third resistor, a fourth resistor, a third capacitor, and a power switching device, one end of the third resistor being connected to the output pin, the other end of the third resistor being connected to the gate of the power switching device, the fourth resistor and the third capacitor being connected in parallel between the gate and emitter of the power switching device, and the auxiliary output pin being connected to the gate of the power switching device; and a ground reference module, including a second capacitor, the negative power supply pin being grounded, one end of the second capacitor being grounded, and the other end of the second capacitor being connected to the positive power supply pin.

[0040] In this embodiment, such as Figure 2 As shown, in the drive and protection module, the drive optocoupler Output pins (such as Figure 2 Pin 11 shown: (After the third resistor) Connected to power switching devices The gate G is used to output a gate drive signal; the third resistor Used for current limiting protection and control of power switching devices Switching speed and suppression of drive signal oscillation. Drive optocoupler. Auxiliary output pins (such as) Figure 2 Pin 10 shown: The fourth resistor is connected to the gate of the IGBT, providing a low-impedance path for Miller current and preventing parasitic conduction of the IGBT. With the third capacitor The fourth resistor is connected in parallel between the gate and emitter E of the IGBT. The third capacitor acts as a pull-down resistor to prevent the IGBT from turning on unexpectedly. Used to suppress high-frequency oscillations.

[0041] In the overvoltage protection module, the driving light Overvoltage protection pin (such as Figure 2 Pin 14 (DESAT) shown is connected to the second resistor. Connected to the first diode anode, first diode The cathode is connected to the bus voltage DCP; the second resistor It serves as a current limiter to prevent the first diode from... The current flowing into the overvoltage protection pin during conduction can damage the drive optocoupler. The first diode When a short circuit occurs between the collector (C) and emitter (E) of the IGBT, reverse cutoff is applied to prevent the bus voltage DCP from breaking down the drive optocoupler. .

[0042] In the ground reference module, drive the optocoupler negative power supply pin (e.g.) Figure 2 Pin 9 shown: Pin 12: and pin 16: Connect to the secondary border Second capacitor One end is connected to the secondary ground, and the other end is connected to the drive optocoupler. The positive power supply pin is connected to the electronic switching device. The power supply terminal of the drain D, such as Figure 2 Pin 13 shown The power supply circuit where it is located is used to drive the optocoupler. The secondary power supply is filtered.

[0043] As an optional embodiment, the switching unit includes: a primary-side control module, including a second diode of a first isolation optocoupler, a sixth resistor, and a control power supply, wherein the anode of the second diode is connected to the input terminal of a safety shutdown signal and is connected to the control power supply through the sixth resistor, and the cathode of the second diode is grounded; and a secondary-side drive module, including a first transistor of a first isolation optocoupler, a fifth resistor, an electronic switching device, and a secondary-side power supply, wherein the emitter of the first transistor is grounded, the collector of the first transistor is connected to the gate of the electronic switching device, and is connected to the secondary-side power supply through the fifth resistor.

[0044] It should be noted that, , , This constitutes the power switching unit of the drive circuit. It is responsible for switching the electronic devices after receiving the STO signal from the external safety controller. Turn off, thereby cutting off the drive optocoupler The effect of the secondary power supply.

[0045] Specifically, the primary-side control module includes a first isolation optocoupler. LED (second diode), sixth resistor and control power supply First isolation optical coupler The anode of the light-emitting diode is connected to the input terminal of the safety shutdown signal STO, and through the sixth resistor Pull up to control power This ensures that the LED does not accidentally turn off when powered on; its cathode is connected to ground. .

[0046] The secondary side drive module includes a first isolation light. The transistor (first transistor), the fifth resistor Electronic switching devices and secondary power supply First isolation optical coupler Transistor emitter grounded Its collector is connected to an electronic switch. The gate G, and through the fifth resistor Pull up to secondary power supply .

[0047] As an optional embodiment, the feedback unit includes: a voltage comparison module, including a comparator and a voltage divider module, wherein the non-inverting input of the comparator is connected to the drain of the electronic switching device, and the inverting input of the comparator is connected to the voltage divider circuit, which is used to divide the voltage of the secondary power supply to an undervoltage threshold voltage; and a signal isolation module, including a light-emitting diode of a second isolation optocoupler, a second transistor of the second isolation optocoupler, a ninth resistor, a tenth resistor, a primary power supply, and a secondary power supply, wherein the anode of the light-emitting diode is connected to the secondary power supply through the ninth resistor, the emitter of the second transistor is grounded, the collector of the second transistor is connected to the fault detection pin of the microcontroller and connected to one end of the tenth resistor, and the other end of the tenth resistor is connected to the primary power supply.

[0048] It should be noted that, , and This constitutes a diagnostic feedback unit, responsible for driving the optocoupler. The secondary side's operating status is communicated to the MCU.

[0049] In this embodiment, such as Figure 2 As shown, in the voltage comparison module, the comparator... The non-inverting terminal is connected to the electronic switching device. Drain D; comparator The inverting input is connected to a voltage divider circuit, which consists of a resistor. and Configuration, used to convert secondary power supply The voltage is divided to the undervoltage threshold voltage; comparator The output terminal is connected to the second isolation optocoupler. The cathode of the light-emitting diode. This circuit is used to compare the driving optocoupler. Secondary voltage and undervoltage threshold voltage: When the secondary voltage is greater than the undervoltage threshold voltage, the comparator... Output high level (set to 1); when the secondary voltage is less than the undervoltage lockout threshold voltage, the comparator outputs low level (set to 0).

[0050] In the signal isolation module, the second isolation optocoupler The anode of the light-emitting diode is connected to the ninth resistor. Connect to secondary power supply The cathode is connected to the comparator. The output terminal; the second isolation optocoupler The emitter of the second transistor (i.e., the secondary-side transistor) is grounded. Its collector is connected to the fault detection pin of the microcontroller (MCU) and through the tenth resistor. Connected to the original side power .

[0051] As an optional embodiment, the voltage divider module includes: a seventh resistor and an eighth resistor connected in series, the inverting input of the comparator connected to the connection node of the seventh resistor and the eighth resistor, and the other end of the eighth resistor grounded; a secondary power supply, and the other end of the seventh resistor connected to the secondary power supply.

[0052] In this embodiment, such as Figure 2 As shown, the voltage divider submodule consists of a first voltage divider resistor connected in series. Second voltage divider resistor Composition: The inverting input of the comparator is connected to the first voltage divider resistor. With the second voltage divider resistor The connection node is used to obtain the reference voltage after voltage division; the second voltage divider resistor The other end connects to the secondary border land The first voltage divider resistor The other end is connected to the secondary power supply. By appropriately selecting the first voltage divider resistor Second voltage divider resistor The resistance value is such that the voltage at the connection node is equal to the driving optocoupler. The undervoltage lockout (UVLO) threshold voltage (undervoltage threshold voltage) enables the comparator Capable of precisely controlling the secondary power supply The actual voltage is compared with the undervoltage threshold voltage to achieve control of the driving optocoupler. Effective monitoring of working status.

[0053] Therefore, the safety torque shutdown circuit provided in this embodiment of the invention, by driving the optocoupler... The secondary power supply is connected in series to the MOSFET switch controlled by the isolation optocoupler, enabling the STO signal to directly cut off the secondary power supply of the drive optocoupler. Utilizing the undervoltage lockout hardware mechanism inside the drive optocoupler, the gate drive output is automatically pulled low to turn off the IGBT after power is cut off, requiring no MCU software intervention throughout the process. A comparator is also introduced. The diagnostic feedback unit, composed of isolation optocouplers, monitors the secondary voltage status in real time and feeds it back to the MCU. This significantly reduces circuit cost and size while ensuring high real-time performance and high safety integrity, and enables independent control and fault isolation of each axis's STO function.

[0054] It should be noted that the above embodiments only demonstrate the STO circuit for cutting off the power supply to the upper bridge arm drive circuit. For the lower bridge arm drive circuit, the connection method of the drive circuit power switch unit and the diagnostic feedback unit is the same; the only difference lies in the connection method of the input drive signal and the IGBT in the drive unit. Users can use one drive circuit power switch unit and one diagnostic feedback unit to simultaneously control the secondary power supply of the drive optocoupler for the upper and lower bridge arms of a single axis.

[0055] According to an embodiment of the present invention, a method embodiment of a control method for a safe torque shutdown circuit is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings for the safe torque shutdown circuit applied to any of the above can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0056] Figure 3 This is a flowchart of a control method for a safe torque shutdown circuit according to an embodiment of the present invention, such as... Figure 3 As shown, the method includes the following steps:

[0057] Step S302: After determining that the first isolation optocoupler has received a safety shutdown signal, control the second diode to turn off.

[0058] In this embodiment, when the safety shutdown signal STO from the external safety controller is valid (e.g., a low-level active signal is set to 0), the first isolation optocoupler... The primary-side light-emitting diode (second diode) is cut off due to the decrease in anode potential.

[0059] In this method, when the external safety controller sends a valid safety shutdown signal (STO is low), the first isolation optocoupler... The primary-side LED is turned off due to the loss of forward bias voltage, thus cutting off the optical coupling transmission between the primary and secondary sides. Since the secondary-side transistor of the optocoupler is turned on by the conduction of the primary-side LED, the secondary-side transistor is also turned off when the LED is turned off.

[0060] By implementing this control method, the driving of the optocoupler was achieved. The rapid disconnection of the secondary power supply, without relying on MCU software intervention or PWM signal software stop, significantly reduces the response delay of the STO function and eliminates the safety risks caused by software runaway or interrupt delay.

[0061] In step S304, the potential of the gate of the electronic switching device is pulled up to the voltage of the secondary power supply through the fifth resistor, so as to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary power supply to the secondary side of the driving optocoupler.

[0062] In this embodiment, when the drive circuit is operating normally, the external safety controller sets the signal STO to 1, and the first isolation optocoupler... When the primary-side LED turns on, it turns on the secondary-side transistor, thus switching the electronic device. The gate is connected to the first isolation optocoupler. Secondary side grounded, at which time electronic switching devices On, secondary power supply Normally drive optocoupler Secondary power supply.

[0063] When the safety function is active, the external safety controller sets the STO signal to 0, and the first isolation optocoupler... Primary-side LED cutoff, electronic switching device The gate is connected to the fifth resistor Pull up to secondary power supply This leads to electronic switching devices Cut off, drive optocoupler The secondary power supply was cut off.

[0064] In this method, when the first isolation optical coupler When the primary-side LED is off, the secondary-side transistor is also off. At this time, the electronic switching device... The conduction path between the gate and ground is broken; due to the fifth resistor Connected between the gate and secondary power supply, the gate potential is achieved through the fifth resistor. The level pulled up to the secondary power supply; for a P-channel enhancement-mode MOSFET, this ensures the gate-source voltage meets the cutoff condition, thereby controlling the electronic switching device. Cut off, disconnecting the power flow from the secondary side to the drive optocoupler. Current path of the secondary side pin.

[0065] By implementing this control method, precise control of the gate potential of the electronic switching device is achieved, ensuring that the optocoupler is driven after the safety turn-off signal is triggered. The secondary power supply is quickly and reliably disconnected; this purely hardware-based pull-up control method avoids power residue problems caused by pull-up failure or unstable control signals, ensuring the smooth operation of the optocoupler. The secondary voltage can stably drop below the undervoltage lockout threshold, thereby triggering the drive optocoupler. Internal hardware protection mechanisms.

[0066] Step S306: The voltage of the output pin is pulled down to the secondary side ground potential of the driving optocoupler by driving the optocoupler.

[0067] In this embodiment, when driving the optocoupler The secondary power supply is due to electronic switching devices When the voltage drops below the undervoltage lockout (UVLO) threshold, the drive optocoupler... The internal undervoltage lockout hardware circuit is triggered, forcing the output pin (such as...) to... Figure 2 The voltage of pin 11 shown is pulled down to the secondary ground potential.

[0068] By implementing this control method, the driving optocoupler is fully utilized. The inherent hardware undervoltage lockout function enables power device shutdown at the pure hardware level, completely eliminating the dependence on MCU software instructions. This not only eliminates the risk of software response delay and code failure, but also ensures an extremely short and deterministic delay time between the issuance of the safe shutdown request and the reliable shutdown of the power device, significantly improving the real-time performance, determinism and functional safety of the multi-axis servo drive in safe torque shutdown scenarios.

[0069] Step S308: When the voltage between the gate and source of the power switching device is detected to be lower than the conduction threshold, the power switching device is controlled to turn off.

[0070] In this embodiment, when the secondary-side voltage drops to the undervoltage threshold voltage, the optocoupler is driven. The internal undervoltage lockout hardware circuit triggers, forcibly pulling the output pin voltage low to ground. This enables reliable IGBT shutdown without the need for software intervention.

[0071] In this method, the optical coupler is driven The undervoltage lockout mechanism forces the voltage at its output pin down to the secondary-side ground potential; this low-level signal is directly applied to the gate of the IGBT power switching device via a current-limiting current, while the pull-down resistor in parallel between the gate and emitter further ensures that the gate potential is clamped at a low level; since the gate-source voltage of the IGBT is therefore lower than its turn-on threshold voltage, the channel inside the IGBT is shut down, blocking the current between the collector and emitter, thereby realizing the power switching device Reliable shutdown.

[0072] By implementing this control method, the power switching devices are ensured. The stable low-level state of the gate potential prevents accidental false turn-on caused by gate floating or Miller effect; combined with the cut-off of the secondary power supply in the preceding steps, a complete hardware safety closed loop is realized from power control to signal drive to power device shutdown, ensuring complete cut-off of motor torque output in the event of an emergency in the multi-axis servo drive.

[0073] As can be seen from the above, through the technical solution provided by the above embodiments of the present invention, after determining that the first isolation optocoupler receives the safety turn-off signal, the second diode is controlled to turn off; the potential of the gate of the electronic switching device is pulled up to the voltage of the secondary power supply through the fifth resistor to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary side to the secondary side of the driving optocoupler; the voltage of the output pin is pulled down to the ground potential of the secondary side of the driving optocoupler through the driving optocoupler; when the voltage between the gate and source of the power switching device is detected to be lower than the conduction threshold, the power switching device is controlled to turn off, thereby achieving the purpose of cutting off the power supply of the secondary side of the driving optocoupler by controlling the P-channel MOSFET through the isolation optocoupler, forcibly pulling down the gate drive voltage to achieve the safe turn-off of the IGBT by utilizing the undervoltage lockout (UVLO) hardware mechanism inside the driving optocoupler, and reporting the fault status to the MCU in real time through an independent diagnostic feedback circuit. This achieves the technical effect of high real-time performance, high reliability, and safe torque turn-off without MCU software intervention, significantly reducing the hardware cost and size of the multi-axis system, and having excellent inter-axis fault isolation capability.

[0074] Therefore, the technical solution provided by the above embodiments of the present invention solves the technical problems of poor real-time performance of the safety torque shutdown circuit due to reliance on software response, and the high cost and large size of the relay solution in the related art.

[0075] As an optional embodiment, the control method of the safe torque shutdown circuit may further include: when the comparator detects that the secondary side voltage of the driving optocoupler is less than or equal to the undervoltage threshold voltage, controlling the second isolation optocoupler to turn on; sending a fault signal to the microcontroller through the second isolation optocoupler to stop the microcontroller from sending input signals to the primary side input pin of the driving optocoupler.

[0076] In this embodiment, when driving the optocoupler When the secondary side voltage is greater than the undervoltage threshold voltage, the second isolation optocoupler The primary side LED is turned off, and the secondary side signal UVLO_FAULT is controlled by the tenth resistor. Pull-up to high level (set to 1); when the secondary side voltage is less than the undervoltage threshold voltage, the second isolation optocoupler... When the primary side LED is turned on, the second transistor is turned on, and the signal UVLO_FAULT is pulled low (set to 0), triggering an alarm from the MCU.

[0077] In this method, when driving the optocoupler When the secondary supply voltage drops to less than or equal to the preset undervoltage threshold voltage due to a safety shutdown operation, the comparator... The system detects that the actual voltage at its input is lower than a reference threshold, and thus outputs a low-level signal to drive the second isolation optocoupler. The primary-side LED is turned on; the second isolation optocoupler... The secondary transistor then turns on, pulling the fault signal pin connected to the microcontroller (MCU) low. Upon detecting this low-level fault signal, the MCU immediately stops sending power to the drive optocoupler. The primary-side input pin sends a pulse width modulation (PWM) signal, thereby completely cutting off the drive command at the software level.

[0078] By implementing this control method, it is ensured that the drive optocoupler is disconnected in hardware. After the secondary power supply is turned on, the MCU can sense and synchronously stop the PWM output in real time, avoiding potential risks caused by software delay. This hardware and software coordinated shutdown strategy not only enhances the system's ability to diagnose fault conditions, but also further improves the reliability and determinism of the safe torque shutdown function through a dual confirmation mechanism.

[0079] Figure 4 This is a block diagram of an STO circuit based on drive optocoupler power supply disconnection for a multi-axis servo driver according to an embodiment of the present invention, such as... Figure 4 As shown, the MCU output , The drive signal is connected to the drive circuit unit, and the drive circuit unit outputs a gate drive signal that is connected to the IGBT and returned to the MCU. Alarm signal; the safety controller outputs an STO signal which is connected to the drive circuit power switch unit, and the drive circuit power switch unit is connected to the power supply. Its power supply output terminal is connected to the drive circuit unit, and at the same time, the drive optocoupler is connected to the drive circuit unit. The secondary power supply status signal is sent to the diagnostic feedback unit, which generates... Alarm signals are transmitted to the MCU to enable IGBT drive control, STO power cut-off protection, power supply diagnosis, and fault feedback functions.

[0080] The control method for the safe torque turn-off circuit provided in this embodiment of the invention will drive the optocoupler. The secondary power supply is connected in series to the MOSFET switch controlled by the isolation optocoupler, so that the STO signal drives the optocoupler. Direct disconnection of the secondary power supply; utilizing the drive optocoupler The internal undervoltage lockout hardware mechanism automatically pulls the gate drive output low to turn off the IGBT after power is cut off, without any MCU software intervention; a comparator is also introduced. The diagnostic feedback unit, composed of isolation optocouplers, monitors the secondary voltage status in real time and feeds it back to the MCU. This significantly reduces circuit cost and size while ensuring high real-time performance and high safety integrity, and enables independent control and fault isolation of each axis's STO function.

[0081] According to embodiments of the present invention, a control device for a safety torque shutdown circuit for implementing the control method of the above-described safety torque shutdown circuit is also provided. Figure 5 This is a schematic diagram of the control device for the safe torque shutdown circuit according to an embodiment of the present invention, such as... Figure 5 As shown, the device includes: a first control unit 501, a second control unit 503, a pull-down unit 505, and a third control unit 507. The device will now be described in detail.

[0082] The first control unit 501 is used to control the second diode to turn off after determining that the first isolation optocoupler has received a safety shutdown signal.

[0083] The second control unit 503 is used to pull up the potential of the gate of the electronic switching device to the voltage of the secondary power supply through the fifth resistor, so as to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary power supply to the secondary side of the driving optocoupler.

[0084] The pull-down unit 505 is used to pull the voltage of the output pin down to the secondary ground potential of the drive optocoupler by driving the optocoupler.

[0085] The third control unit 507 is used to control the power switching device to turn off when the voltage between the gate and source of the power switching device is detected to be lower than the conduction threshold.

[0086] It should be noted that the first control unit 501, the second control unit 503, the pull-low unit 505 and the third control unit 507 mentioned above correspond to steps S302 to S308 in the above embodiments. The four units and the corresponding steps implement the same instances and application scenarios, but are not limited to the content disclosed in the above embodiments.

[0087] As can be seen from the above, in the solution described in the above embodiments of the present invention, a first control unit is used to control the second diode to turn off after determining that the first isolation optocoupler has received a safety turn-off signal; a second control unit is used to pull up the potential of the gate of the electronic switching device to the voltage of the secondary power supply through the fifth resistor, so as to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary side to the secondary side of the driving optocoupler; a pull-down unit is used to pull down the voltage of the output pin to the ground potential of the secondary side of the driving optocoupler through the driving optocoupler; and a third control unit is used to control the power switching device to turn off when the voltage between the gate and source of the power switching device is detected to be lower than the conduction threshold. Through the above technical solution, the goal of cutting off the power supply to the secondary side of the driving optocoupler by controlling the P-channel MOSFET through the isolation optocoupler, forcibly pulling down the gate drive voltage to achieve the safe turn-off of the IGBT by using the undervoltage lockout (UVLO) hardware mechanism inside the driving optocoupler, and reporting the fault status to the MCU in real time through an independent diagnostic feedback circuit is achieved. This achieves the technical effect of high real-time performance, high reliability, and safe torque turn-off without MCU software intervention, significantly reducing the hardware cost and size of the multi-axis system, and having excellent inter-axis fault isolation capability.

[0088] Therefore, the technical solution provided by the above embodiments of the present invention solves the technical problems of poor real-time performance of the safety torque shutdown circuit due to reliance on software response, and the high cost and large size of the relay solution in the related art.

[0089] As an optional embodiment, the control device of the safe torque shutdown circuit further includes: a fourth control unit, used to control the second isolation optocoupler to turn on when the comparator detects that the secondary side voltage of the driving optocoupler is less than or equal to the undervoltage threshold voltage; and a stop unit, used to send a fault signal to the microcontroller through the second isolation optocoupler to stop the microcontroller from sending input signals to the primary side input pin of the driving optocoupler.

[0090] According to one aspect of the present invention, a multi-axis servo driver is provided, wherein the multi-axis servo driver uses the control method of the safety torque shutdown circuit described above.

[0091] According to one aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein the program executes the control method for a safe torque shutdown circuit as described above.

[0092] According to one aspect of the present invention, a processor is provided for running a program, wherein the program executes the control method for the safe torque shutdown circuit described above.

[0093] According to one aspect of the present invention, a computer program product is provided, including computer instructions, which, when executed by a processor, execute a control method for a safe torque shutdown circuit as described above.

[0094] Optionally, in this embodiment, the computer-readable storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any communication device in a group of communication devices.

[0095] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: after determining that the first isolation optocoupler receives a safety shutdown signal, controlling the second diode to turn off; pulling up the potential of the gate of the electronic switching device to the voltage of the secondary power supply through the fifth resistor to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary side to the secondary side of the driving optocoupler; pulling down the voltage of the output pin to the secondary side ground potential of the driving optocoupler through the driving optocoupler; and controlling the power switching device to turn off when it is detected that the voltage between the gate and source of the power switching device is lower than the conduction threshold.

[0096] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when the comparator detects that the secondary side voltage of the driving optocoupler is less than or equal to the undervoltage threshold voltage, controlling the second isolation optocoupler to turn on; sending a fault signal to the microcontroller through the second isolation optocoupler to stop the microcontroller from sending input signals to the primary side input pin of the driving optocoupler.

[0097] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0098] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0099] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between units or modules may be electrical or other forms.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0102] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0103] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0104] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A safe torque shutdown circuit, characterized in that, include: The unit comprises a drive unit, a switching unit, and a feedback unit, among which... The driving unit includes a driving optocoupler and a power switching device. The gate of the power switching device is connected to the output pin of the driving optocoupler, and the driving optocoupler converts the input signal from the microcontroller into a driving signal to drive the power switching device to turn on or off. The switching unit includes an electronic switching device and a first isolation optocoupler. The gate of the electronic switching device is connected to the collector of the first isolation optocoupler, the drain of the electronic switching device is connected to the positive power supply pin of the driving optocoupler, and the source of the electronic switching device is connected to the secondary power supply. This is used so that when the first isolation optocoupler receives a safety shutdown signal, it controls the electronic switching device to turn off to cut off the power supply of the secondary power supply. The feedback unit includes a comparator and a second isolation optocoupler. The output terminal of the comparator is connected to the cathode of the light-emitting diode of the second isolation optocoupler. When the secondary voltage of the driving optocoupler is less than the undervoltage threshold voltage, the comparator sends a fault signal to the microcontroller through the second isolation optocoupler.

2. The safe torque shutdown circuit according to claim 1, characterized in that, The driving optocoupler includes primary-side pins, which include a power supply pin, a ground pin, a fault output pin, a positive input pin, and a negative input pin. The driving unit includes: The drive and fault detection module includes a first resistor, a first capacitor and a primary power supply. The power supply pin is connected to the primary power supply. One end of the first resistor is connected to the primary power supply. The other end of the first resistor is connected to the fault output pin. One end of the first capacitor is connected to the primary power supply. The other end of the first capacitor is grounded and connected to the grounding pin. The fault output pin is externally connected to the microcontroller to send a fault alarm signal to the microcontroller. The drive signal input module has a positive input pin that receives a positive input signal output by the microcontroller and an inverted input pin that receives an inverted input signal output by the microcontroller.

3. The safe torque shutdown circuit according to claim 1, characterized in that, The driving optocoupler includes secondary-side pins, which include the output pin, auxiliary output pin, overvoltage protection pin, negative power supply pin, and positive power supply pin. The driving unit includes: An overvoltage protection module includes a second resistor and a first diode. One end of the second resistor is connected to the overvoltage protection pin, and the other end of the second resistor is connected to the anode of the first diode. The cathode of the first diode is connected to the bus voltage. The drive and protection module includes a third resistor, a fourth resistor, a third capacitor, and the power switching device. One end of the third resistor is connected to the output pin, and the other end of the third resistor is connected to the gate of the power switching device. The fourth resistor and the third capacitor are connected in parallel between the gate and the emitter of the power switching device. The auxiliary output pin is connected to the gate of the power switching device. The grounding reference module includes a second capacitor, the negative power supply pin is grounded, one end of the second capacitor is grounded, and the other end of the second capacitor is connected to the positive power supply pin.

4. The safe torque shutdown circuit according to claim 1, characterized in that, The switching unit includes: The primary-side control module includes a second diode of the first isolation optocoupler, a sixth resistor, and a control power supply. The anode of the second diode is connected to the input terminal of the safety shutdown signal and is connected to the control power supply through the sixth resistor. The cathode of the second diode is grounded. The secondary-side drive module includes a first transistor of the first isolation optocoupler, a fifth resistor, the electronic switching device, and the secondary-side power supply. The emitter of the first transistor is grounded, the collector of the first transistor is connected to the gate of the electronic switching device, and is connected to the secondary-side power supply through the fifth resistor.

5. The safe torque shutdown circuit according to claim 1, characterized in that, The feedback unit includes: The voltage comparison module includes the comparator and the voltage divider module. The non-inverting terminal of the comparator is connected to the drain of the electronic switching device, and the inverting terminal of the comparator is connected to the voltage divider circuit. The voltage divider circuit is used to divide the voltage of the secondary power supply to the undervoltage threshold voltage. The signal isolation module includes the light-emitting diode of the second isolation optocoupler, the second transistor of the second isolation optocoupler, a ninth resistor, a tenth resistor, the primary power supply, and the secondary power supply. The anode of the light-emitting diode is connected to the secondary power supply through the ninth resistor. The emitter of the second transistor is grounded. The collector of the second transistor is connected to the fault detection pin of the microcontroller and connected to one end of the tenth resistor. The other end of the tenth resistor is connected to the primary power supply.

6. The safe torque shutdown circuit according to claim 5, characterized in that, The pressure dividing submodule includes: A seventh and eighth resistor are connected in series, the inverting input of the comparator is connected to the connection node of the seventh and eighth resistors, and the other end of the eighth resistor is grounded; The other end of the seventh resistor is connected to the secondary power supply.

7. A control method for a safe torque shutdown circuit, characterized in that, The safe torque shutdown circuit applied to any one of claims 1 to 6 comprises: After determining that the first isolation optocoupler has received the safety shutdown signal, the second diode is controlled to turn off; The potential of the gate of the electronic switching device is pulled up to the voltage of the secondary power supply through the fifth resistor, so as to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary power supply to the secondary side of the driving optocoupler. The voltage of the output pin is pulled down to the secondary ground potential of the drive optocoupler through the drive optocoupler; When the voltage between the gate and source of the power switching device is detected to be lower than the turn-on threshold, the power switching device is controlled to turn off.

8. The method according to claim 7, characterized in that, The method further includes: When the comparator detects that the secondary side voltage of the driving optocoupler is less than or equal to the undervoltage threshold voltage, it controls the second isolation optocoupler to turn on. The fault signal is sent to the microcontroller via the second isolation optocoupler to stop the microcontroller from sending input signals to the primary input pin of the driving optocoupler.

9. A control device for a safe torque shutdown circuit, characterized in that, The control method applied to the safe torque shutdown circuit according to claim 7 or 8 includes: A first control unit is configured to control the second diode to turn off after determining that the first isolation optocoupler has received the safety shutdown signal; The second control unit is used to pull up the potential of the gate of the electronic switching device to the voltage of the secondary power supply through the fifth resistor, so as to control the electronic switching device to turn off, thereby cutting off the power supply from the secondary power supply to the secondary side of the driving optocoupler. A pull-down unit is used to pull the voltage of the output pin down to the secondary ground potential of the drive optocoupler via the drive optocoupler; The third control unit is used to control the power switching device to turn off when the voltage between the gate and source of the power switching device is detected to be lower than the conduction threshold.

10. A multi-axis servo driver, characterized in that, The multi-axis servo driver uses the control method of the safe torque shutdown circuit described in claim 7 or 8.

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