Allegro MicroSystems, Inc. products

The A4918 is an N-channel power MOSFET driver capable of controlling MOSFETs connected in a 3-phase bridge arrangement and is specifically designed for automotive applications with high-power inductive loads, such as BLDC motors. A unique charge pump regulator provides the supply for the MOSFET gate drive for battery voltages down to 7 V and allows the A4918 to operate with a reduced gate drive down to 4.5 V. Gate drive voltage and strength are programmable to help reduce EMC issues. A bootstrap capacitor is used to provide the above-battery supply voltage required for N-channel MOSFETs with an additional above-battery charge pump to ensure that the bootstrap capacitors remain charged when held in the on state. Full control is provided over all six power MOSFETs in the 3-phase bridge, allowing motors to be driven with block commutation or sinusoidal excitation.