【Introduction】Brushless DC motors (BLDC) are widely used because of their long life, less maintenance and high efficiency. Based on this, BLDC is widely used in DIY and professional-grade battery-powered related motor products, such as power tools, garden tools, commercial and consumer multi-axis aircraft, battery-powered household appliances, robots, low-speed electric vehicles, etc. Different types of motors and control strategies are used in these products, so their voltage, torque, and product specifications are different. Is there a general control chip to realize the control of different motor products?
Yes, this is Infineon’s new three-phase motor intelligent driver chip 6EDL7141, which is an intelligent three-phase motor control gate driver that can be used in battery-powered motor control applications in various occasions. The 6EDL7141 gate driver supports 12-48V battery-powered applications. This chip has fully programmable design capabilities. It can realize a variety of PWM control and braking mode control through a large number of parameter configurations, and has complete protection functions, such as Overcurrent, overheating, stall detection, etc.
Next, you will learn about the overall architecture, features, and innovative gate drive capabilities of this three-phase motor intelligent driver chip, and use its GUI tool to easily design and debug online. At the same time, the existing reference evaluation boards can also make Designers can quickly implement product designs and accelerate product time-to-market.
A three-phase motor control gate driver IC for battery-powered BLDC motor control, the MOTIX TM 6EDL7141 is the latest three-phase motor control gate driver IC from Infineon. The 6EDL7141 can be used to develop high-performance battery-operated products using BLDC or PMSM motors in many applications including cordless power tools, garden power products, and automated guided vehicles. The MOTIX TM 6EDL7141 has more than 50 parameters programmable using the SPI interface and can be fully parameterized to drive various MOSFETs for optimum system efficiency.
The MOTIX™ 6EDL7141 offers great flexibility in a 48-pin VQFN package with an operating voltage of 5.5-60V, configurable gate drive sink and source currents up to 1.5A, and can efficiently drive a variety of MOSFETs to Perfect for every application. Thanks to the built-in dual charge pump, its gate driver supply voltage can be set to 7V, 10V, 12V or 15V and is regulated even at low battery voltages. The MOTIX™ 6EDL7141 gate driver parameters can also be adjusted to control the slew rate to minimize EMI in the system. All settings of the MOTIX™ 6EDL7141 can be changed quickly through an easy-to-use GUI.
Figure 1 Schematic diagram of the control application of the brushless DC motor
Figure 2 Schematic diagram of typical application of 6EDL7141
Rich power architecture
The integrated buck regulator requires only one external capacitor and Inductor to power the microcontroller and Hall sensors in the motor, further reducing peripheral components and the required PCB space. High-performance power tools also often require high-accuracy current measurements using an accurate ADC reference voltage. The MOTIX™ 6EDL7141 uses an advanced linear power regulator architecture powered by an internal buck converter to provide the best signal quality under any input and output conditions while optimizing power efficiency.
As can be seen from Figure 3 and Figure 4, the high-efficiency synchronous Buck DC-DC converter integrated inside MOTIX™ 6EDL7141 provides high-voltage power supply for the entire system, and the input voltage range is as wide as 5.5-60V. If PVDD ≥9.5V, VDDB can provide up to 600mA , while an LDO regulator powered by the Buck converter output can provide up to 300mA of low-noise digital power. As a system-level design, the power supply method can be flexibly selected, such as: Buck or LDO output power supply for external components (MCU, Hall, etc.), and provide power for the matching MCU, thus eliminating the need for power configuration.
Figure 3 6EDL7141 chip internal power management architecture diagram
Figure 4 6EDL7141 chip internal power management architecture diagram
Adjustable gate drive parameters
The power supply in the system is supplied by a buck regulator, which provides the bias supply for all three-phase high/low side drivers. The charge pump-based three-phase gate driver supports 100% duty cycle output, and thanks to the dual-charge charge pump design, its gate driver supply voltage can be set to 7V, 10V, 12V or 15V through SPI parameters, even if Allows driving standard level MOSFETs also at low battery voltages. The high- and low-side gate drive capability is up to 1.5A, and the built-in adjustable drive current design is also adjusted through SPI parameter setting.
In addition to being able to select gate driver source and sink currents, the 6EDL7141 features an innovative and unique drive slew rate control function that optimizes EMI and switching in battery powered applications by controlling the gate drive voltage rise slope and rise and fall times loss. Dynamically optimizing dv/dt enables the use of MOSFETs for optimum performance. This can greatly reduce switching losses and facilitate the increase in operating frequency.
PWM mode and braking method
6EDL7141 provides 4 different PWM modes and a variant mode to meet different MCU needs. The first mode is the 6 PWM mode, which drives the gate driver in the most classic way by using 6 PWM signals from the MCU.
The 6EDL7141 also has 3 other modes that simplify the PWM generation on the MCU side with intelligence. These, along with integrated protection features, bring high reliability and a faster development process to drive applications. Smart dead time control will ensure no shoot-through occurs under any circumstances. Highly configurable braking modes provide safe responses to motor or system events. Different PWM modes are set through SPI.
Figure 5 4 different PWM modes
While braking, the 6EDL7141 will set the gate driver output to a predefined state when a braking event occurs, and when integrated with XMC1400 or other MCUs, the system reliability can be improved by dual braking both internally and externally . External braking is handled by the external MCU or any other fault source in the system. The 6EDL7141 provides the following braking modes, as shown in Figure 6.
// High side braking – all upper tubes on, lower tubes off
// low side braking – all lower tubes on, upper tubes off
// Alternate Braking – Alternate between high side and low side braking
// Hi-Z – All outputs are set to Hi-Z
The pass-through problem of the inverter requires great attention. The intelligent processing of dead time is also an effective means to effectively prevent the pass-through of the device. The dead time of 6EDL7141 can be programmed, and the dead time of the rising edge and the dead time of the falling edge can be independently programmed ( via SPI). When editing the dead time, you need to ensure that the dead time is sufficient for the configuration of the slew rate and the requirements of the selected MOSFET.
Figure 6 Braking Mode
Figure 7 6EDL7141 built-in protection logic details
The 6EDL7174 integrates 3 operational amplifiers with adjustable offset and gain, which can be used to measure the current in the inverter through shunt resistors. As shown in Figure 8, it supports single, dual or triple flow detection. At the same time, there are 3 Hall sensor comparators with adjustable anti-spike function, which can realize adjustable protection parameter settings to adapt to different system power and different fault protection threshold settings.
Among them, OCP overcurrent protection is an extremely important protection feature in motor applications. The internal OCP comparator mechanism of 6EDL7174 has integrated high-precision DAC reference voltage, positive OCP and negative OCP functions, PWM truncation, with anti-spike timer, Fault trigger event configuration, etc. Of course, OCP overcurrent protection also exists in the following positions: such as in shunt or Rdson, DVDD, LDO OCP, buck converter OCP and other positions. At the same time, the UVLO power supply of the chip is not missing, such as PVDD, gate driver power supply, under-voltage lockout protection of DVDD LDO, and system-level over-temperature alarm and protection shutdown, configurable watchdog, rotor based on Hall sensor input Lock detection and memory faults together realize systematic integrated protection for motor control and improve the reliability of the motor system.
Figure 8 Supports single (A), dual (B) and triple (C) parallel current sense configurations
The response to fault protection can also be configured by software, such as braking, high resistance, latching or not latching faults to suit different application requirements.
Graphical User Interface (GUI) Tools
Infineon provides GUI tools for motor drive control design. Users can select devices and configure parameters arbitrarily through the GUI interface. These can be visualized parameter configuration and effects only by writing parameters, which greatly simplifies and saves design. time. The adjusted parameters can be stored in the OTP. After completing the OTP operation, some configurations can also be changed through SPI commands, 6EDL7141 provides up to 50 parameters that can be configured through SPI.
Using GUI and SPI, even non-professional motor control designers can easily design excellent motor control systems using 6EDL7141.
Figure 9 Infineon Motor Control GUI
Evaluation Boards Speed Design-to-Market Process
Infineon now offers an evaluation version EVAL_6EDL7141_TRAP_1SH for this three-phase smart driver, a motor driver board designed for a battery powered brushless DC (BLDC) motor driver with trapezoidal wave control for applications such as cordless power tools. The evaluation board is used with a motor containing an integrated Hall sensor for rotor position sensing, combining an XMC1400 series microcontroller with a 6EDL7141 three-phase smart driver IC and Infineon power MOSFETs. As can be seen from the design of the evaluation board, due to its high level of integration, the 6EDL7141 reduces system component count and time-to-market, while significantly improving power density, system performance and peak power pulse capability.
The evaluation board features fully configurable operating parameters, integrated and configurable on-board power and gate drive outputs, and configurable protection modes. Built-in debugger, connect directly to USB for debugging, the evaluation board can be run stand-alone or through the Infineon Motor Control GUI.
The evaluation board has a DC input voltage of 12 V to 24 V, a rating of 18 V, a maximum input current of 30 A, and a peak operating power of 500W. It can be used as a design reference for motor control applications including cordless power tools, garden products, automated guided vehicles, e-bikes, drones, and battery-powered robots.
Figure 10 Evaluation version EVAL_6EDL7141_TRAP_1SH
Infineon’s three-phase smart motor gate driver 6EDL7141, with perfect integration and a variety of integrated functions, can greatly reduce the number and cost of external components, including built-in power converters, intelligent driving, sensing detection, comprehensive protection improvement Reliable, configurable parameter implementation provides easy and fast design for battery-powered motor drive applications, shortening product design development cycles and time-to-market.
Source: 21st Century Power Network