Allegro MicroSytems Announces New Single Phase Brushless DC Pre-driver IC
Allegro MicroSystems Inc. announced the first device in a series of single-phase brushless dc motor pre-drivers used to control high current fans, blowers or pumps. Outputs are designed to drive all N-Channel MOSFET H-Bridges with supply voltages between 8 and 36V.
The motor speed is regulated by either a PWM (pulse width modulated) input or external analog voltage (typically thermistor). Motor speed can be monitored with the FG output and minimum speed can be programmed with an external voltage. This new device is targeted at the office automation, telecommunications, consumer and industrial markets.
Maximum motor current is controlled with the internal PWM fixed off time current regulator. Synchronous rectification is employed in the PWM off cycle to reduce power dissipation. Startup current can be ramped up for reduced supply current surges and lock detection with auto restart functions reduces damage due to motor overheating. A single resistor is used to program the commutation delay to prevent shoot through and to reduce fan noise. An internal 5V regulator is provided for the Hall element.
Protection features include thermal shutdown with hysteresis, under voltage lockout (UVLO), crossover current and locked rotor protection with auto restart. Special power up sequencing is not required.
Allegro’s A4930 is supplied in a lead (Pb) free 28L QFN package (suffix ET) with exposed power tab. It has a 5 x 5mm footprint and 0.90mm nominal height. It is priced at $0.77 in quantities of 1,000 and has a 14-week typical lead-time to market.
