Metal Oxide Semiconductor Field Effect Transistors (mosfets) control electric devices for these applications. However, using mosfet as a switch brings new technical challenges to the design of electronic control modules, including electromagnetic interference (EMI) and thermal management, current sensing, power-off braking, and diagnosis and protection. Integrated circuit (IC) motor driver products developed by Texas Instruments integrate analog functions to help electronic control module designers meet these challenges while reducing solution size and development time.

In this article, we will discuss specific analog functions integrated into motor drive integrated circuits that can help meet these design challenges.

Reduce electromagnetic interference (EMI)

Reducing EMI can be achieved through functions and solutions at the chip level and PCB level. A key method to reduce EMI is to control the pulse width modulation (PWM) edge rate. Gate drive products, such as DRV8705-Q1, DRV8706-Q1, DRV8714-Q1 and DRV8718-Q1 gate drives for brushed DC (BDC) motors, and Three-Phase DRV8343- for brushless DC (BLDC) motors Q1 integrates intelligent gate drive technology, which is specifically used to control the PWM edge slew rate. In addition, these devices also provide the function of selecting the slew rate to minimize EMI. Another common technique to reduce EMI is to vibrate the master clock frequency. The DRV10983-Q1 three-phase BLDC motor driver with integrated MOSFET also integrates the jitter function of the master clock frequency, which reduces the amplitude by spreading the peak value across the entire spectrum.

Thermal management

Based on the load being driven, the working current and stall current of the motor have a wide range of values. For high current loads, gate drive products allow you to choose to use discrete MOSFETs for design. The electronic control module designer can optimize the layout to achieve the best thermal management. For low-load current loads, devices such as DRV8873-Q1, DRV8874-Q1 and DRV8876-Q1 with integrated H-bridge MOSFETs can be used to drive the load while achieving the best thermal management. In addition, low-current loads driven by a three-phase BLDC motor driver can use the DRV10983-Q1 with integrated MOSFET. Please note: DRV10983-Q1 also integrates a commutation algorithm, so that a single-chip solution can drive the motor.

Current sensing

The current in the motor is measured to detect circuit and motor faults, and the ripple count is used to infer the motor position. All Texas Instruments BDC and BLDC motors and gate drive products integrate current sense amplifiers to amplify the voltage across the Resistor. In addition, DRV8106-Q1, DRV8706-Q1, DRV8714-Q1 and DRV8718-Q1 also provide an online current sense amplifier. Using online current sensing measurement, the direction of motor rotation can also be determined.

Traditionally, car windows are driven by BDC motor drivers. However, system designers are studying the use of BLDC motors to drive windows, because BLDC motors are quieter. In addition, the use of BLDC motors to rotate the seat bases of autonomous vehicles is also considered. The three-phase smart gate drive DRV8343-Q1 with integrated current sensing function can be used in these applications.

Power-off brake

With the MOSFET solution, when the motor power is turned off, the motor can rotate freely. In this case, manually moving the load, such as manually opening or closing the power cord, may cause a large back EMF to be generated, thereby damaging electronic devices. The DRV8714-Q1 and DRV8718-Q1 for luggage control module applications integrate the power-off braking function. This function can measure the generated voltage and apply an electronic brake to the motor. This function prevents the motor from rotating and thus stops generating current.

Diagnosis and protection

When controlling the motor, it is necessary to detect circuit faults and protect the system from these faults. BDC and BLDC gate drivers integrate diagnostic circuits to detect open and short circuits. In addition, we also provide some integrated circuit failure mode distribution and pin failure mode analysis information to assist functional safety design when needed.

Implement control modules in body applications

Table 1 maps the products to the motors used in these applications.

Table 1: A series of products suitable for body motor applications

Other resources:

· Understand aboutBDCwithBLDCMore information on motor drives.

· Please refer to the following application report: “Learn about smart gate drive. “

· Please refer to the following technical articles: “What is a smart gate drive architecture?– NS1part” with”Integrated intelligence NS1part:EMImanage. “

· Please refer to the white paper: “Smart gate drive. ” From single layer with speed control reference design,12V, Programmable, three-phaseBLDCmotor driverStart designing.

· WatchCar motorEMCOverview .

In addition, the product range covers single half-bridge products to multi-H-bridge gate driver products, and you can easily scale your design according to your specific design situation.