Date: 15/10/2012

Full-bridge MOSFET controller for use with external N-channel power MOSFETs

Allegro MicroSystems, Inc has announced 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. It has a supply voltage range of 7 V to 50 V. This device is suitable for commercial and industrial applications such as portable power tools, lawn and garden equipment, industrial blowers, lifts and conveyors, and forklifts.

Allegro’s A4957 is provided in a 24-pin ES package and is designed to address the performance and price point driving motors in these applications. A unique charge pump regulator offers 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 offer the above battery supply voltage required for N-channel MOSFETs. A bootstrap charge management system facilitates 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 offer indication of under-voltage and over-temperature faults.

The A4957SESTR-T is available in a 24-pin, 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: www.allegromicro.com

Source: Allegro Microsystems