BLDC Motor Controllers Made Easy with X-FAB

X-FAB's brushless DC motor driver solution facilitates highly cost-effective designs by combining controlling and driving functionality on one chip. X-FAB's technology enables a fully integrated solution with integrated driver and pre-driver and PWM control which can be operated at temperature up to 150 degrees Celsius. Due to the high temperature tolerance significant costs savings on system level can be achieved.


Brushless DC Motor Driver - Block Diagram


Brushless DC Motor Driver

This example BLDC driver synchronizes via the inductive response of the motor. No additional components, such as Hall sensors, are necessary. It can drive motors for pumps, fans or other applications. The application can be manufactured with X-FAB’s high-voltage technologies that cover wide temperature and voltage ranges.



CPU, PWM Control (Microcontroller)

This controller requires sub-micron CMOS with NVM (EEPROM and FLASH). X-FAB provides a wide range of digital cells and memory blocks for this purpose. Alternatively, a dual microcontroller with 35K-equivalent gates, 2kB RAM, 32kB Flash or 128B E2PROM memory, and a maximum of 50 mA low-voltage internal load current could be used to achieve the same results.



5V Voltage Regulator and Power On Reset (POR)

This internal voltage regulator required for internal voltage supply can provide a 30mA~100mA load current with low ripple/noise; and the regulator features  low stand-by current. The POR provides the start-up function. A jFET and/or depletion MOS is available for this purpose. X-FAB also offers IP for this through its IP portal.



Communication Interface and External Bus control

The communication interface is used to set speed and other motor operation characteristics. An external bus such as CAN or LIN can be included. The technologies used for that are fully qualified for automotive applications.



Control Circuitry: Driver Control and Motor Control Unit

The RC oscillator, PLL (phase locked loop), PWM (pulse width modulation) and frequency controller are used to set power and speed of the brushless motor. A temperature controller monitors the chip as well as the motor temperature. The control circuitry can be manufactured with standard CMOS available in all X-FAB CMOS technologies.



Power Transistor Pre-Driver and Internal Driver

Power transistors drive the 3-phase BLDC motor inductors, either integrated or off-chip. In this example, the power transistors are integrated on-chip, which is common for small power devices. The typical voltage for the gate drive ranges from 5V to 20V VDS. The driver NMOS transistors are high-side capable (gate voltage above VDD). This functionality is provided either by a bootstrap construction or the usage of a charge pump. The internal high-voltage NMOS transistors tolerate inductive loads and are highly robust with low RDSon. They are available with X-FAB’s XH035 and XH018 HV technologies.