Allegro : Dc motor pre-driver IC controls high-current devices

The A4930 from Allegro MicroSystems Europe is a single-phase brushless DC motor pre-driver integrated circuit designed to control high-current devices such as fans, blowers or pumps with supply voltages from 8 V to 36 V.

Key features include PWM current control, locked-rotar protection with auto restart, outputs to drive an all N-channel MOSFET H-bridge, a minimal requirement for external components, and programmable commutation delay, soft start and minimum speed.

The motor speed is regulated by either a PWM (pulse width modulated) input or an external analogue voltage – typically from a thermistor. The speed can be monitored via the device’s FG (fan gain) output, and minimum speed is programmed with an external voltage.

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. Start-up current can be ramped up for reduced supply current surges, and lock detection with automatic 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 5 V regulator is provided for the Hall element.

Protection features include thermal shutdown with hysteresis, undervoltage lockout (UVLO), crossover current and locked-rotor protection with auto restart. Special power-up sequencing is not required.
The new device is targeted at the office automation, telecommunications, consumer and industrial markets.

The A4930 is supplied in a lead (Pb) free 28-pin QFN package (suffix ET) with exposed power tab. It has a 5x 5 mm footprint
and 0.90 mm nominal height.

About Allegro

Allegro MicroSystems, Inc. is a leader in developing, manufacturing and marketing high-performance power integrated circuits and integrated Hall-effect magnetic sensors. Allegro’s innovative solutions serve high-growth applications within the automotive, communications, computer/office automation, consumer and industrial markets. Allegro is headquartered in Worcester, Massachusetts (USA) with design and applications centres located in North and South America, Asia, and Europe.

Further information about Allegro can be found at

Allegro MicroSystems Europe Ltd
Melita House
124 Bridge Road
KT16 8LH
Tel:+33 (0) 4 50512359
Fax: +33 (0) 4 50512083

Note: The above text is the public part of the press release obtained from the manufacturer (with minor modifications). EETimes Europe cannot be held responsible for the claims and statements made by the manufacturer. The text is intended as a supplement to the new product presentations in EETimes Europe magazine.

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