Texas Instruments' driver provides a code-free sensorless trapezoidal control solution for BLDC motor applications

Texas Instruments' MCT8329A offers a single-chip, code-free sensorless ladder solution for three-phase brushless direct current (BLDC) motors that require high-speed operation or very fast start-up times. The device provides three half-gate drivers, each capable of driving both high - and low-side n-channel power MosFeTs.

The device uses an internal charge pump to generate the correct grid drive voltage and a bootstrap-up circuit to enhance the high-side mosFeTs. Drip charge pump includes support for 100% duty cycle. The grid drive architecture supports peak grid drive currents up to 1 A source and 2 A sinks. The MCT8329A supports a single power supply with a wide input range of 4.5 V to 60 V.

Sensorless trapezoidal control is height configurable by setting registers in non-volatile EEPROM (MCT8329A1I), ranging from motor startup behavior to closed-loop operation, allowing independent operation when configured. The motor current is sensed using an integrated current sensing amplifier that supports a single external shunt resistor.

The driver receives speed commands via PWM input, analog voltage, variable-frequency square wave, or I2C command. Multiple protection features are designed to protect equipment, motors and systems from failure events.

Features

● Three-phase BLDC gate driver with an integrated sensorless motor control algorithm:
-   Code-free high-speed trapezoidal control
-   Supports electrical frequency: up to 3 kHz
-   Very fast startup time: < 50 ms
-   Fast deceleration: < 150 ms
-   Supports 120° or 150° modulation to improve the acoustic performance
-   Forward and reverse wind-milling support
-   Analog, PWM, frequency, or an I2C-based control input
-   Configurable motor startup and stop options
-   Optional closed-loop speed or power control, open-loop voltage control
-   Five-point configurable reference profile support
-   Anti-voltage surge prevents overvoltage
-   Variable monitoring through the DACOUT
● PWM frequency: up to 100 kHz
● Accurate LDO (AVDD) 3.3V ±3%, 50 mA support with AVDD connected to the VREG
● 65 V three phase half-bridge gate driver:
● Drives three high-side and three low-side n-channel MOSFETs, operating voltage range: 4.5V to 60 V. Drives three high-side and three low-side N-Channel MOSFETs, operating voltage range: 4.5V to 60 V
-   Supports 100% PWM duty-cycle
-   Bootstrap-based gate driver architecture
-   Peak source/sink current: 1 A/2 A (max.)
● Suite of integrated protection features:
-   Supply undervoltage lockout (UVLO)
-   Motor lock detection is available in three types
-   Overcurrent protection (OCP)
-   Thermal shutdown (TSD)
-   Fault condition indication pin (nFAULT)
-   Optional fault diagnostics over the I2C interface
● Integrated current sense amplifier
● Adjustable gain: 5 V/V, 10 V/V, 20 V/V, and 40 V/V
● Low-power sleep mode: 5 µA (max.) at VPVDD = 24 V and TA = +25°C
● Speed loop accuracy: ＜3% with an internal clock
● Independent driver shutdown path (DRVOFF)
● Spread spectrum for EMI mitigation

Applications

● Brushless direct current (BLDC) motor module
● Cordless vacuum cleaner
● Hvac and ventilator
● Electrical fans and pumps
● Wireless garden and Power Tools: Lawn mower