Servo driver power output circuit based on GaN power device

Abstract

The utility model discloses a servo driver power output circuit based on a GaN power device, and relates to the technical field of motor driving. Wherein the power supply module converts and provides electric energy, the main control board sends a PWM signal to the PWM buffer module, the PWM buffer module adjusts the time sequence of the signal and then transmits the signal to the GaN driving module, the GaN driving module comprises three driving units which are connected in sequence, each unit is composed of a GaN power device and a plurality of resistors and capacitors and is responsible for receiving the adjusted PWM signal and controlling the power output of an external load, the power supply module comprises an LDO power supply unit and an isolation power supply unit, the PWM buffer module comprises two voltage level conversion units, and stable transmission and processing of signals are ensured. By using the GaN power device, the limitation of the traditional Si power device in the application of the servo driver is overcome, and a servo driver design scheme which is more efficient, more compact, more reliable and better in cost is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of motor drive, and particularly relates to a power output circuit of a servo driver based on a GaN power device. BACKGROUND

[0002] As a key component of automation control and precision positioning systems, the performance of a servo driver directly affects the efficiency and precision of the entire system. Over the past few decades, servo driver technology has undergone significant development, especially in the design of power output circuits.

[0003] Initially, the power output circuit of a servo driver mainly relied on traditional silicon (Si) power devices. Silicon, as the first generation of semiconductor materials, has a long history and wide application in the power electronics industry. Silicon power devices, with their relatively mature technology, lower cost and higher reliability, have played an important role in servo drivers. However, with the rapid development of industrial automation, electric vehicles, aerospace and other fields, higher performance requirements have been placed on servo drivers, including higher power density, lower energy consumption, better thermal management performance and higher switching frequency. In this context, some limitations of silicon power devices in servo driver applications have begun to emerge. The physical properties of silicon power devices determine that their power handling capacity per unit volume or weight is limited, which restricts the miniaturization and lightweight of servo drivers; silicon power devices have high switching losses under high voltage and large current conditions, resulting in low overall efficiency, which is particularly evident at high frequencies; due to high switching losses, silicon power devices generate a large amount of heat during operation, which requires a more complex and efficient heat dissipation system, increasing the volume and weight of the system; the performance of silicon power devices in high-frequency applications is limited, which restricts the potential of servo drivers in fast dynamic response and high-precision control.

[0004] Existing servo drives generally use silicon-based insulated gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs) as power switching elements. To improve power handling capability, multiple silicon power devices are integrated into the same module, forming a multi-chip module. The drive circuit is responsible for providing appropriate drive signals for the power device, ensuring its reliable opening and closing; the drive circuit usually contains overvoltage, overcurrent and short circuit protection functions to protect the power device from damage. Servo drives usually use closed-loop control strategies, using position feedback, speed feedback and current feedback to accurately control the movement of the motor; to improve efficiency and reduce noise and vibration during motor operation, space vector modulation technology is widely used in PWM signal generation; due to the heat generated by silicon power devices during switching, existing technical solutions include the use of heat sinks, fans and heat pipes to control device temperature; thermal sensors are used to monitor the temperature of the power device to ensure it operates within a safe operating range; servo drives integrate power management circuits, including voltage conversion and filtering circuits, to ensure stable power supply; to communicate with the host computer or other devices, servo drives are usually equipped with communication interfaces such as CAN, EtherCAT or USB.

[0005] The application of traditional Si (silicon) power tubes in servo drives has the following disadvantages: The power density of Si power tubes is relatively low, which means that a larger volume and weight are required to achieve the same power output. This limits its use in applications with high power density requirements, such as portable electronic devices, electric vehicles and precision industrial robots; Si power tubes have high switching losses, which result in lower overall system efficiency than more advanced semiconductor materials. These losses are mainly due to higher gate charge and output capacitance, which consume more energy during switching operations; although Si power tubes may have an advantage in terms of unit price, due to their lower efficiency and power density, additional components such as larger heat sinks and magnetic elements may need to be added to the system design, which can increase the overall system cost; Si power tubes have limited performance at high frequencies, which limits the performance of servo drives in high-frequency applications, such as precision control systems that require fast response, which can affect the dynamic response speed and accuracy of the system; Si power tubes generate more heat during power conversion, which poses a challenge to thermal management. More complex heat dissipation designs and larger heat dissipation areas may be required, which not only increase the volume and weight of the system, but also may affect the reliability and lifespan of the device. Invention content

[0006] The purpose of the present application is to provide a GaN power device-based servo driver power output circuit, which overcomes the limitations of traditional Si power devices in servo driver applications by using GaN power devices, and realizes a more efficient, more compact, more reliable and cost-optimized servo driver design scheme.

[0007] To achieve the above purpose, the embodiment of the present application provides a GaN power device-based servo driver power output circuit, comprising a power module, a main control board module, a PWM buffer module and a GaN drive module; wherein,

[0008] The power module is connected with the main control board module, the PWM buffer module and the GaN drive module respectively, and is used for power conversion and power supply to the main control board module, the PWM buffer module and the GaN drive module;

[0009] The main control board module is connected with the PWM buffer module, and is used for sending a first PWM signal to the PWM buffer module;

[0010] The PWM buffer module is connected with the main control board module and the GaN drive module, and is used for receiving the first PWM signal sent by the main control board module, changing the timing characteristics of the first PWM signal to obtain a second PWM signal, and sending the second PWM signal to the GaN drive module;

[0011] The GaN drive module is connected with the PWM buffer module, and is used for receiving the second PWM signal sent by the PWM buffer module and outputting power to an external load.

[0012] According to the above method of the embodiment of the present application, the following additional technical features can also be possessed:

[0013] Further, the power module comprises an LDO power unit and three sequentially connected isolation power units, and the LDO power unit is connected with the three sequentially connected isolation power units.

[0014] Further, the LDO power unit comprises an LDO power chip U15, a capacitor C81, a capacitor C82, a capacitor C83 and a capacitor C84;

[0015] Among them, the capacitor C81 and the capacitor C82 are connected in parallel between the 2 pin and the 1 pin of the LDO power chip U15, used for filtering the input of the LDO power chip U15, and short-circuiting the 1 pin and the 3 pin of the LDO power chip U15, used for enabling the LDO power chip U15; the capacitor C83 and the capacitor C84 are connected in parallel between the 2 pin and the 5 pin of the LDO power chip U15, used for filtering the output of the LDO power chip U15;

[0016] The isolated power supply unit includes an isolated power supply chip U12, a capacitor C61, a capacitor C62, a capacitor C63, a capacitor C64 and a resistor R130;

[0017] The capacitor C61 and the capacitor C62 are connected in parallel, one end of which is connected to a 5V power supply and the other end of which is connected to a 4th pin and a 6th pin of the isolated power supply chip U12, for power input filtering; the capacitor C63 and the capacitor C64 are connected in parallel, one end of which is connected to an 8th pin of the isolated power supply chip U12 and the other end of which is connected to a 10th pin and a 12th pin of the isolated power supply chip U12, for connecting a +5V_U_UP network to a subsequent chip; the capacitor C63 and the capacitor C64 are used for filtering the isolated power supply output of the isolated power supply chip U12; a 5V power supply is connected to a 1st pin of the isolated power supply chip U12 through a resistor R130, for enabling the isolated power supply chip U12; and a +5V_U_UP network is connected to a 7th pin of the isolated power supply chip U12, for selecting a 5V voltage of the isolated power supply output.

[0018] Further, the PWM buffer module includes two voltage level conversion units connected in sequence.

[0019] Further, the voltage level conversion unit includes a voltage level conversion chip U2, a voltage level conversion chip U4, a resistor R137, a resistor R138, a resistor R5, a resistor R6, a resistor R7, a resistor R10, a resistor R11, a resistor R12, a capacitor C26, a capacitor C27, a capacitor C37 and a capacitor C38.

[0020] The +3.3V power supply is connected to a 1st pin of the voltage level conversion chip U2 and the voltage level conversion chip U4 through a resistor R137, for providing a 3.3V power supply for the voltage level conversion chip U2 and the voltage level conversion chip U4.

[0021] The +5V power supply is connected to a 1st pin of the voltage level conversion chip U2 and the voltage level conversion chip U4 through a resistor R138, for providing a 5V power supply for the voltage level conversion chip U2 and the voltage level conversion chip U4; and the actual circuit selects the resistor R137 or the resistor R138 according to a first PWM signal level of the isolated power supply chip.

[0022] The capacitor C26 is connected between the ground and a 1st pin of the voltage level conversion chip U2, for power input filtering on a signal input side; and the capacitor C27 is connected between the ground and an 11th pin of the voltage level conversion chip U2, for power input filtering on a signal output side.

[0023] The resistor R5, the resistor R6 and the resistor R7 are connected between a 10th pin, a 9th pin and an 8th pin of the voltage level conversion chip U2 and the ground, for pulling down the first PWM signal.

[0024] Capacitor C37 is connected between ground and pin 1 of voltage level conversion chip U4 for signal input side power input filtering; capacitor C38 is connected between ground and pin 11 of voltage level conversion chip U4 for signal output side power input filtering;

[0025] Resistors R10, R11 and R12 are respectively connected between pin 10, 9, 8 of voltage level conversion chip U4 and ground for pulling down the first PWM signal;

[0026] The pins 6 and 7 of voltage level conversion chip U2 and voltage level conversion chip U4 are shorted and grounded;

[0027] The first PWM signal is input through pins 2, 3, 4 of voltage level conversion chip U2 and voltage level conversion chip U4 and output through pins 10, 9, 8 to the GaN drive module as the second PWM signal;

[0028] The overcurrent signal / OCL_O is connected to pin 12 of voltage level conversion chip U2 and voltage level conversion chip U4 for shutting down the first PWM signal output when overcurrent occurs.

[0029] Further, the GaN drive module includes three GaN drive units connected in sequence.

[0030] Further, the GaN drive unit includes GaN power device U1, resistor R2, resistor R3, capacitor C11, capacitor C12, capacitor C13, capacitor C14, capacitor C15, capacitor C16, capacitor C17, capacitor C18, capacitor C19, capacitor C20, capacitor C21 and capacitor C22.

[0031] Capacitors C12 and C18 have one end connected to ground and pin 15 of GaN power device U1 and the other end connected to +5V power supply and pin 14 of GaN power device U1 for chip power input filtering;

[0032] Capacitors C19 and C20 have one end connected to IS_U- network and pin 11 of GaN power device U1 and the other end connected to +5V_U_UP network and pin 10 of GaN power device U1 for power input filtering of the internal high-side MOS tube driving power supply of GaN power device U1;

[0033] Capacitors C21 and C22 have one end connected to ground and the other end connected to pin 12 and pin 13 of GaN power device U1 respectively for second PWM signal input filtering;

[0034] Capacitor C11, capacitor C13, capacitor C14, capacitor C15, capacitor C16, capacitor C17 one end bus power negative pole-VBUS and GaN power device U1 6, 17, 18 pin, one end bus power positive pole +VBUS and GaN power device U1 7 pin, for GaN power device U1 bus power input filter;

[0035] Resistor R2 and resistor R3 one end connects the second PWM signal, the other end connects GaN power device U1 12, 13 pin respectively, for controlling GaN power device U1 internal high side MOS tube and low side MOS tube opening and closing respectively;

[0036] GaN power device U1 5 pin is power output pin, connected to external load, for output power to external load.

[0037] Compared with the prior art, the GaN power device-based servo driver power output circuit provided by the embodiment of the present application has the following beneficial technical effects:

[0038] Compared with the traditional silicon-based power device, the GaN device has higher switching frequency, lower on-resistance and smaller chip size, so that the energy efficiency and power density of the circuit can be significantly improved, and the circuit can occupy smaller physical space under the same output power, while reducing energy loss.

[0039] The circuit design of the embodiment of the present application includes a power module, which provides stable and isolated power supply for the entire circuit through the combination of LDO (low dropout linear voltage regulator) power unit and isolation power unit, reduces the influence of power fluctuation on circuit performance, and improves the stability and reliability of the circuit.

[0040] The PWM buffer module of the embodiment of the present application realizes the timing characteristic adjustment of the PWM signal sent by the main control board module through the series connection of two voltage level conversion units, thereby optimizing the output power control of the GaN drive module to the external load, reducing signal interference and misoperation, and further improving the reliability of the circuit.

[0041] The isolation power unit in the power module of the embodiment of the present application can output different voltage levels according to actual needs, providing appropriate power voltage for different components in the circuit. This flexible power management capability makes the circuit can adapt to a wider range of application scenarios and meet different power output requirements.

[0042] The overcurrent signal detection function is integrated in the PWM buffer module of the embodiment of the present application, when the overcurrent condition is detected, the PWM signal output can be automatically closed, so as to protect the power device in the circuit from being damaged, the design enhances the safety and reliability of the circuit, and reduces the risk of equipment damage caused by overcurrent failure. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The structural block diagram of the GaN power device-based servo driver power output circuit of the embodiment of the present application is shown;

[0044] Figure 2 The power module structural block diagram of the GaN power device-based servo driver power output circuit of the embodiment of the present application is shown;

[0045] Figure 3 The PWM buffer module structural block diagram of the GaN power device-based servo driver power output circuit of the embodiment of the present application is shown;

[0046] Figure 4 The GaN drive module structural block diagram of the GaN power device-based servo driver power output circuit of the embodiment of the present application is shown. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below in combination with the drawings. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0048] The terms "comprising" and "having" and any variations thereof in the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to the process, method, product or device.

[0049] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0050] As Figure 1 shown, the embodiment of the application provides a GaN power device-based servo driver power output circuit, which mainly consists of four key modules: a power module, a main control board module, a PWM buffer module and a GaN drive module. These four modules cooperate with each other to realize the power output function of the servo driver.

[0051] Among them, the power module is responsible for power conversion and provides stable power supply for other modules, and is connected with the main control board module, the PWM buffer module and the GaN drive module respectively to ensure the power required for the normal work of each module; the main control board module serves as the control center of the circuit and is responsible for sending the PWM (pulse width modulation) signal, and is connected with the PWM buffer module to send the generated first PWM signal to the PWM buffer module; the PWM buffer module receives the first PWM signal sent by the main control board module and processes it to change its timing characteristics to obtain the second PWM signal, and is connected with the main control board module and the GaN drive module as a signal transmission bridge, by changing the timing characteristics of the PWM signal, the PWM buffer module can optimize the signal quality to ensure that the GaN drive module can accurately and efficiently receive and execute instructions; the GaN drive module receives the second PWM signal sent by the PWM buffer module and controls the power output of the external load according to the signal, and is connected with the PWM buffer module to receive the processed PWM signal, and uses GaN power devices with the advantages of high frequency, high efficiency, low loss, etc., which can significantly improve the performance of the servo driver.

[0052] The application of GaN power devices makes the circuit have higher efficiency and lower loss, and the reasonable connection and signal processing between the modules ensure the stability and reliability of the circuit, and the circuit structure is flexible and can be adjusted and optimized according to actual needs to adapt to different application scenarios.

[0053] As Figure 2 shown, the power module of the embodiment of the application is a key part of the servo driver power output circuit, which is responsible for converting the input power into stable power required by each module and ensuring the normal operation of the entire circuit.

[0054] The power module of the embodiment of the application includes an LDO power unit and three isolation power units connected in sequence, wherein,

[0055] The LDO power unit is composed of an LDO power chip U15 and related filter capacitors (C81, C82, C83, C84). Specifically, the LDO power chip U15 is a low-dropout linear regulator that can convert the input higher voltage into stable lower voltage output.

[0056] In the filter capacitor, the capacitor C81 and C82 are connected in parallel at the input end (2 pin and 1 pin) of the LDO power chip U15, for filtering the input power supply, reducing the influence of power fluctuation on the LDO power chip; the capacitor C83 and C84 are connected in parallel at the output end (2 pin and 5 pin) of the LDO power chip U15, for filtering the output power supply, ensuring the stability and ripple of the output power supply; by shorting the 1 pin and 3 pin of the LDO power chip U15, the enable control of the LDO power chip can be realized, that is, whether to start working is controlled.

[0057] The isolation power supply unit is composed of an isolation power chip U12 and related filter capacitors (C61, C62, C63, C64) and an enable resistor R130. Specifically, the isolation power chip U12 is a power chip with isolation function, which can convert the input power supply into isolated output power supply, thereby preventing electrical interference between different parts of the circuit.

[0058] In the filter capacitor, the capacitor C61 and C62 are connected in parallel at the input end (2 pin) of the isolation power chip U12, for filtering the input power supply; the capacitor C63 and C64 are connected in parallel at the output end (8 pin) of the isolation power chip U12, for filtering the output power supply, ensuring the stability and ripple of the output power supply. At the same time, the two capacitors are also connected to the IS_U-network, providing isolated power supply input for subsequent chips; the +5V power supply is connected to the 1 pin of the isolation power chip U12 through the resistor R130, for enabling the isolation power chip, that is, controlling whether to start working; the +5V_U_UP network is connected to the 7 pin of the isolation power chip U12, for selecting the voltage level of the isolation power output, and in this embodiment, 5V voltage output is selected.

[0059] The power module provides stable and reliable power input for each module in the servo driver power output circuit through the cooperation of the LDO power supply unit and the isolation power supply unit. Among them, the LDO power supply unit is responsible for providing stable low-voltage power output, and the isolation power supply unit is responsible for providing isolated power output to prevent electrical interference between different parts of the circuit. This design ensures the stability and reliability of the entire circuit, providing a strong guarantee for the normal work of the servo driver.

[0060] As shown in Figure 3 The PWM buffer module of the embodiment of the present application is responsible for receiving the first PWM signal from the main control board module and processing it to generate a second PWM signal with appropriate timing characteristics, and then driving the GaN power device.

[0061] Specifically, the PWM buffer module is located between the main control board module and the GaN drive module. The main function of this module is to buffer and process the first PWM signal sent by the main control board module to ensure the stability and accuracy of the signal during transmission. By changing the timing characteristics of the PWM signal, the PWM buffer module can generate a second PWM signal that meets the requirements of the GaN drive module.

[0062] The voltage level conversion unit is the core part of the PWM buffer module, which contains two voltage level conversion chips (U2 and U4) connected in sequence, as well as a series of resistance and capacitance elements. These elements work together to achieve the functions of level conversion and filtering of the PWM signal.

[0063] Specifically, the U2 and U4 chips are responsible for converting the first PWM signal from one level to another. This conversion is necessary because the main control board module and the GaN drive module may work in different voltage ranges. Through voltage level conversion, it can be ensured that the PWM signal will not be distorted or damaged due to level mismatch during transmission.

[0064] The resistors R137, R138, R5, R6, R7, R10, R11, R12 and the capacitors C26, C27, C37, C38 and other elements in the circuit play the role of filtering and pulling down. They can filter out high-frequency noise and interference in the PWM signal, while ensuring that the signal maintains a stable level state during transmission. In addition, the selective welding of resistors R137 and R138 allows the circuit to be flexibly adjusted according to the PWM signal level emitted by the isolation power supply chip.

[0065] The first PWM signal is input through the 2, 3, 4 pins of the voltage level conversion chips U2 and U4. These pins are the signal input terminals of the chip, responsible for receiving the first PWM signal from the main control board module.

[0066] Inside the voltage level conversion chip, the first PWM signal is processed by the level conversion circuit and converted to a level range suitable for the operation of the GaN drive module. During this process, the resistance and capacitance elements play the role of filtering and stabilizing the level.

[0067] The second PWM signal after level conversion is output through the 10, 9, 8 pins of the voltage level conversion chips U2 and U4. These pins are the signal output terminals of the chip, responsible for sending the processed PWM signal to the GaN drive module. In order to enhance the reliability of the circuit, the overcurrent signal / OCL_O is connected to the 12 pin of the voltage level conversion chips U2 and U4. When an overcurrent fault occurs in the circuit, this signal will trigger the protection mechanism inside the chip, closing the output of the PWM signal, thereby avoiding damage to the circuit and the load.

[0068] In summary, the PWM buffer module ensures the stability and accuracy of the PWM signal during transmission through level conversion and filtering functions, thereby achieving precise control of the GaN power device.

[0069] As Figure 4 shown, the GaN drive module of the present application is responsible for receiving the second PWM signal processed by the PWM buffer module and controlling the GaN power device to output power to the external load accordingly. This module is composed of three GaN drive units connected in sequence. Such a design not only ensures stable transmission of signals but also enhances driving capability, ensuring efficient operation of the servo driver.

[0070] Each GaN drive unit contains a GaN power device and a series of resistors and capacitors used in conjunction with it. These elements work together to achieve precise control of the GaN power device.

[0071] Among them, GaN power device U1 as the core of the drive unit, GaN power device U1 has the characteristics of high efficiency, high frequency and low loss, is the key to realize high performance output of servo driver. Its 5 pins as power output pins, directly connected to the external load, responsible for converting electrical energy into mechanical energy or other forms of energy.

[0072] Resistors R2 and R3 are connected to the 12 and 13 pins of GaN power device U1, respectively, for receiving the second PWM signal. According to the high and low levels of the signal, they control the opening and closing of the high-side MOS tube and low-side MOS tube inside GaN power device U1, respectively, thereby achieving power output control of the external load.

[0073] Capacitors C11 to C22 play multiple roles in the GaN drive unit. Among them, capacitors C12 and C18 are used for chip power input filtering to ensure that GaN power device U1 receives stable and reliable power supply; capacitors C19 and C20 are used for power input filtering of the high-side MOS tube drive power inside GaN power device U1, further improving the stability of the drive signal; capacitors C21 and C22 are responsible for second PWM signal input filtering, effectively reducing signal interference; and capacitors C11, C13, C14, C15, C16, and C17 form a bus power input filtering network, providing clean and stable bus power for GaN power device U1.

[0074] In summary, the GaN drive module and its internal GaN drive units ensure efficient and stable operation of the servo driver power output circuit. These elements work together not only to improve the performance of the servo driver but also to provide a strong guarantee for its reliable operation in various application scenarios.

[0075] It should be noted that, in the present application, the terms "comprising", "containing" or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element. In addition, it should be noted that the scope of the methods and apparatus in the present application is not limited to performing functions in the order shown or discussed, but can also include performing functions in a substantially simultaneous manner or in reverse order, for example, the described methods can be performed in an order different from that described, and various steps can also be added, omitted, or combined. In addition, features described with reference to certain examples can be combined in other examples.

[0076] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the specific embodiments described above, which are merely illustrative and not restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the scope protected by the claims.

Claims

1. A GaN power device based servo driver power output circuit, characterized by, The application relates to a GaN drive module, which comprises a power module, a main control board module, a PWM buffer module and a GaN drive module. The power module is connected with the main control board module, the PWM buffer module and the GaN drive module, is used for power conversion, and supplies power to the main control board module, the PWM buffer module and the GaN drive module. The main control board module is connected with the PWM buffer module, and is used for sending a first PWM signal to the PWM buffer module. The PWM buffer module is connected with the main control board module and the GaN drive module, receives the first PWM signal sent by the main control board module, changes the time sequence characteristics of the first PWM signal, obtains a second PWM signal, and sends the second PWM signal to the GaN drive module. The GaN drive module is connected with the PWM buffer module, receives the second PWM signal sent by the PWM buffer module, and outputs power to an external load.

2. The servo driver power output circuit of claim 1, wherein, The power module comprises an LDO power unit and three sequentially-connected isolation power units.

3. The servo driver power output circuit of claim 2, wherein, The LDO power unit comprises an LDO power chip U15, capacitors C81, C82, C83 and C84. The capacitors C81 and C82 are connected in parallel between the 2th pin and the 1th pin of the LDO power chip U15, are used for filtering the input of the LDO power chip U15, and short the 1th pin and the 3th pin of the LDO power chip U15, so as to enable the LDO power chip U15; the capacitors C83 and C84 are connected in parallel between the 2th pin and the 5th pin of the LDO power chip U15, and are used for filtering the output of the LDO power chip U15. The isolation power unit comprises an isolation power chip U12, capacitors C61, C62, C63, C64 and a resistor R130. The capacitors C61 and C62 are connected in parallel, one end of which is connected with a 5V power supply and the 2th pin of the isolation power chip U12, and the other end is connected with the ground and the 4th pin and the 6th pin of the isolation power chip U12, and is used for power input filtering; the capacitors C63 and C64 are connected in parallel, one end of which is connected with the 8th pin of the isolation power chip U12 and the +5V_U_UP network, and the other end is connected with the 10th pin and the 12th pin of the isolation power chip U12 and the IS_U network, and the capacitors C63 and C64 are used for isolation power output filtering of the isolation power chip U12; the +5V power supply is connected with the 1th pin of the isolation power chip U12 through the resistor R130, and is used for enabling the isolation power chip U12; the +5V_U_UP network is connected with the 7th pin of the isolation power chip U12, and is used for selecting the 5V voltage of the isolation power output.

4. The servo driver power output circuit of claim 1, wherein, The PWM buffer module comprises two sequentially-connected voltage level conversion units.

5. The servo driver power output circuit of claim 4, wherein, The voltage level conversion unit comprises a voltage level conversion chip U2, a voltage level conversion chip U4, a resistor R137, a resistor R138, a resistor R5, a resistor R6, a resistor R7, a resistor R10, a resistor R11, a resistor R12, a capacitor C26, a capacitor C27, a capacitor C37, and a capacitor C38. The +3.3V power supply is connected to the 1 pin of the voltage level conversion chip U2 and the voltage level conversion chip U4 through the resistor R137, and provides a 3.3V power supply for the voltage level conversion chip U2 and the voltage level conversion chip U4. The +5V power supply is connected to the 1 pin of the voltage level conversion chip U2 and the voltage level conversion chip U4 through the resistor R138, and provides a 5V power supply for the voltage level conversion chip U2 and the voltage level conversion chip U4. The capacitor C26 is connected between the ground and the 1 pin of the voltage level conversion chip U2, and is used for signal input side power input filtering. The capacitor C27 is connected between the ground and the 11 pin of the voltage level conversion chip U2, and is used for signal output side power input filtering. The resistor R5, the resistor R6, and the resistor R7 are connected between the 10 pin, the 9 pin, and the 8 pin of the voltage level conversion chip U2 and the ground, respectively, and are used for pulling down the first PWM signal. The capacitor C37 is connected between the ground and the 1 pin of the voltage level conversion chip U4, and is used for signal input side power input filtering. The capacitor C38 is connected between the ground and the 11 pin of the voltage level conversion chip U4, and is used for signal output side power input filtering. The resistor R10, the resistor R11, and the resistor R12 are connected between the 10 pin, the 9 pin, and the 8 pin of the voltage level conversion chip U4 and the ground, respectively, and are used for pulling down the first PWM signal. The 6 pin and the 7 pin of the voltage level conversion chip U2 and the voltage level conversion chip U4 are short-circuited and grounded.

6. The servo driver power output circuit of claim 1, wherein, The first PWM signal is input through the 2 pin, the 3 pin, and the 4 pin of the voltage level conversion chip U2 and the voltage level conversion chip U4, and the second PWM signal is output to the GaN drive module through the 10 pin, the 9 pin, and the 8 pin.

7. The servo driver power output circuit of claim 6, wherein, The overcurrent signal / OCL_O is connected to the 12 pin of the voltage level conversion chip U2 and the voltage level conversion chip U4, and is used for closing the first PWM signal output when overcurrent occurs. The GaN drive module comprises three GaN drive units connected in sequence. The GaN drive unit comprises a GaN power device U1, a resistor R2, a resistor R3, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C16, a capacitor C17, a capacitor C18, a capacitor C19, a capacitor C20, a capacitor C21, and a capacitor C22. The one end of the capacitor C12 and the capacitor C18 is grounded and connected to the 15 pin of the GaN power device U1, and the other end is connected to the +5V power supply and the 14 pin of the GaN power device U1, and is used for chip power input filtering. Capacitor C19 and capacitor C20 one end of the IS_U- network and the 11 pin of GaN power device U1, the other end of the +5V_U_UP network and the 10 pin of GaN power device U1, for the power input filter of the internal high side MOS tube driving power supply of GaN power device U1; Capacitor C21 and capacitor C22 one end of the ground, the other end of the 12 and 13 pin of GaN power device U1 respectively, for the second PWM signal input filter; Capacitor C11, capacitor C13, capacitor C14, capacitor C15, capacitor C16, capacitor C17 one end of the bus power negative pole-VBUS and the 6,17,18 pin of GaN power device U1, one end of the bus power positive pole+VBUS and the 7 pin of GaN power device U1, for the bus power input filter of GaN power device U1; Resistance R2 and resistance R3 one end of the second PWM signal, the other end of the 12,13 pin of GaN power device U1 respectively, for controlling the opening and closing of the internal high side MOS tube and low side MOS tube of GaN power device U1 respectively; The 5 pin of GaN power device U1 is the power output pin, connected to the external load, for outputting power to the external load.

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