Full-bridge pre-driver

Allegro MicroSystems has released a new power MOSFET pre-driver IC for large brush DC motors. Dubbed the A3940, the new device is targeted at the automotive marketplace.

The device provides four high-current gate-drive outputs capable of driving a wide range of power N-Channel MOSFETs. Bootstrap capacitors are used to provide the above-battery supply voltage required for N-Channel FETs.

An internal charge pump for the high side allows for DC (100% duty cycle) operation of the bridge. PHASE and ENABLE input terminals are provided for use in controlling the speed and direction of a DC motor with externally applied PWM control signals.

Protection features include supply undervoltage and overvoltage, programmable dead time adjustment for cross-conduction protection, thermal shutdown, and motor lead short-to-supply and short-to-ground protection.

The A3940 is manufactured using Allegro’s ABCD3 (Allegro Bipolar CMOS DMOS 3rd generation) process and is supplied in either a 28-lead TSSOP thermally enhanced package or in a standard 28-lead SOIC package.

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