NCD83591 Brushless DC Motor 3-Phase Gate Driver for Industrial Automation

Industrial or factory automation is one of the fastest growing end applications for BLDC motors within the industrial segment. As factories move from more traditional brushed or stepper motors to BLDC for higher efficiency and performance, the need for three-phase gate drivers is growing. Multiple motors are used in end application designs such as factory robots and collaborative robots.

The NCD83591 is a 60 V, 3-phase gate driver designed for brushless DC (BLDC) motor applications. It integrates three independent half-bridge drivers and a sense amplifier to provide an easy-to-use gate driver. This solution is ideal for industrial applications due to its small package size and gate drive architecture, which provides high power density and ease of use. The maximum input voltage of the NCD83591 is 60 V, which provides sufficient margin to drive motors with rated voltages typically between 12 and 42 V, suitable for most industrial automation applications. Coupled with the high power density and ease of use that industrial customers value, the NCD83591 provides an ideal solution for these applications.

Power density

The NCD83591 is available in a 4 mm x 4 mm QFN-28 package and includes an integrated, fully configurable current sense amplifier, a low-side 14 V regulator, and a high-side charge pump. This product is the industry's smallest 60 V, 3-phase gate driver with at least one sense amplifier integrated. The small package size and single integrated amplifier provide a perfect BLDC motor drive solution for space-sensitive applications. This product allows customers to quickly implement trapezoidal commutation to drive the motor while minimizing the number of external components to achieve a small solution size. The integrated three-phase half-bridge drive significantly reduces the size compared to discrete solutions using traditional independent half-bridge driver ICs.

Figure 1: NCD83591 IC

Ease of Use - Trapezoidal Motor Control

The NCD83591 gate driver uses a single integrated amplifier and is ideal for trapezoidal motor control commutation. This method is the most common BLDC commutation method in the industrial market and is the best balance between optimal torque and design simplicity. Although field-oriented control (FOC) and direct flux control (DFC) commutation methods are becoming more popular in more complex motor control applications, trapezoidal commutation is still the standard in the 12 to 40 V BLDC industrial market from an ease of use perspective.

Easy-to-use constant current gate driver

The gate drive architecture is another advantage of using the NCD83591 three-phase gate driver. This product implements a constant current gate drive instead of the traditional constant voltage gate drive. Constant current drive provides the same switching network (motor phase winding) transition time, but saves the cost of series gate resistors and has a smaller drive circuit. The elimination of the series gate resistor also helps prevent self-turn-on. See Figure 2 below for more details. However, the most significant advantage of constant current gate drive is the ability of the IC to sense the actual gate-source (Vgs) voltage of the FET it is driving. The gate sense feature makes the NCD83591 stand out in terms of ease of use because it enables benefits such as dead time optimization and true cross conduction protection.

Dead time is usually programmed into the MCU to turn off the FET of one phase before turning on the FET of the other phase. Extra time is usually programmed to ensure that cross conduction does not occur because timing varies with temperature, power supply and aging. The NCD83591 can detect the gate-source voltage and turn off the FET before turning on the opposite FET in the same phase. This eliminates the need to program the dead time into the MCU because the IC handles it, minimizing the dead time during pulse width modulation (PWM) without being affected by delays. The product can also detect external faults that power the FET and react appropriately by disabling the opposite FET in the same phase when the FET should not be enabled.

Figure 2: Constant current and constant voltage gate drive