MOSFET controller suits portable power tools and more

Allegro MicroSystems Inc. announces a new full-bridge MOSFET controller for use with external N-channel power MOSFETs. The A4957 is designed for applications with high-power brush dc motors and features a wide supply voltage range of 7 to 50 V. The new device is targeted for commercial and industrial applications such as portable power tools, lawn and garden equipment, industrial blowers, lifts and conveyors, and forklifts.

Offered in the 24-lead ES package, Allegro’s A4957 is intended to meet the performance and price point driving motors in these applications. A unique charge pump regulator provides full (>10 V) gate drive for supply voltages down to 7 V or as low as 4.5 V with a reduced gate drive. A bootstrap capacitor is used to provide the above battery supply voltage required for N-channel MOSFETs. A unique bootstrap charge management system ensures that the bootstrap capacitor is always sufficiently charged to supply the high-side gate drive circuit.

Each of the power MOSFETs is controlled independently, but all are protected from shoot-through by dead time that can be configured by the user through an external resistor. Integrated diagnostics indicate under-voltage and over-temperature faults.

The A4957SESTR-T is supplied in a 24-lead, 4 × 4 × 0.75 mm QFN package with an exposed pad for enhanced thermal dissipation. It is lead (Pb) free, with 100% matte tin lead-frame plating (suffix T).

For more information, contact Allegro MicroSystems Inc., 115 Northeast Cutoff, Worcester, MA 01606. Phone: (508) 853-5000.