Allegro introduces a new three-phase, sensorless, brushless DC (BLDC) motor controller for use with external N-channel power MOSFETs that is designed for various pump, blower and cooling fan automotive applications. The motor is driven using block commutation (trapezoidal drive) where phase commutation is determined, without the need for independent position sensors, by monitoring the motor back-emf. A programmable mo¬tor start-up scheme allows the Allegro A4960 to be adjusted for a wide range of motor and load combinations.
External bootstrap capacitors are used to provide the above battery supply voltage required to drive the N-channel MOSFETs. An automatic internal bootstrap charge management scheme ensures that the bootstrap capacitor is always sufficiently charged for safe operation of the power MOSFETs. The power MOSFETs are protected from shoot-through by integrated crossover control and adjustable dead time.
Integrated diagnostics provide indication of undervoltage, overtemperature and power bridge faults and can be configured to protect the power FETs under most short circuit conditions. Detailed diagnostics are available as a serial data word or through a programmable diagnostic output. The A4960 is supplied in a 32 lead eLQFP (suffix JP). This package is available in lead (Pb) free versions, with 100% matte-tin lead frame plating (-T).
