Automotive-grade full-bridge MOSFET pre-driver IC from Allegro MicroSystems

The A3941 is targeted at the requirements of the automotive market, which is looking to new technologies to replace belt-driven and hydraulic actuators with more efficient systems. Most belt-driven actuators provide a loss to system efficiency even when not in use. Eliminating this older technology is made possible by the adoption of full electronic systems utilising various electric motor technologies to replace the belt driven actuators, and the A3941 is designed to fit the emerging needs of this market.

The new device is capable of driving four external N-channel MOSFETs in a full-bridge configuration. It is typically used in brush DC motor drive applications where high currents in combination with high ambient temperatures require the use of external MOSFETs. The A3941 is designed with high-temperature automotive applications in mind, and is rated over the full automotive temperature range (-40°C to +150°C junction temperature) and the full battery supply range of 7 V to 50 V.

An integrated charge pump provides full gate drive for battery voltages down to 7 V and reduced gate drive for battery voltages as low as 5.5 V. Flexible input logic can be configured to PWM (pulse-width modulation) on the high side or the low side, with seamless internal synchronous rectification logic operating on the high side or the low side depending on the PWM logic choice.

An adjustable drain-to-source monitor provides adjustable short-circuit protection for the external MOSFETs. Improved fault diagnostics offers an enhanced ability to decode and identify faults, and smart bootstrap capacitor management automatically monitors the bootstrap charge and generates a refresh pulse when required. Also included is a low-current ‘sleep’ mode and cross-conduction protection with adjustable dead time.

The A3941 is supplied in the 28-pin eTSSOP small profile thermally efficient package with exposed pad.