Allegro MicroSystems, Inc. offers two new full-bridge gate drivers for automotive and industrial applications. Built-in features include flexible interface logic, EMI mitigation for programmable gate drivers, motor current feedback and a variety of diagnostic functions, these devices require few external components and are offered in a 4mm x 4mm QFN package, compared to comparable 5mm x 5mm devices 36% smaller. Also available in direct control (A89505) and pulse width modulation (A89506) options, these devices upgrade key components to make system design simpler, replacing mechanical relays with solid-state drives to improve performance and reliability.
The solid-state design of the A89505 and A89506 also makes them ideal for battery-powered applications, including brushed DC motors (such as building automation and robotics), improving reliability and battery life while enabling a smaller design footprint. And it has excellent automotive applications, including window and door actuators, electric vehicle charger locks, electronic parking brakes and folding mirrors.
Designers can pack the functionality they need into a smaller system footprint, reducing BOM and PCB size, while increasing performance and enhancing the consumer experience. Because both drivers include built-in current sensing, the need for external current sensing resistors is eliminated and the requirement for external components is reduced to a minimum of seven. Integrated diagnostics further prevent the need for additional microprocessor programming and additional circuitry.
Steve Lutz, Director of Allegro's Drivers Business Line. "In addition to being 36% smaller than other drivers on the market, the A89505 and A89506 include advanced features and capabilities that help designers reduce the overall PCB size and fit everything into a more compact module. Both drivers are larger than relays Or discrete systems are easier to use and implement, and improve overall reliability while reducing power consumption." "And as vehicles continue to move towards full electrification, designers are looking for systems that can be designed without increasing the size of the system. Motor drives that improve performance and battery life. The same goes for those designing for IoT and industrial applications,”
Compared to mechanical relays, gate drivers help provide better motor control and reduce the requirement for external components. Programmable gate drivers reduce EMI and transients due to fast switching, and gate current can be adjusted to better control the slew rate of external MOSFETs.
Both devices have a current limit detection flag that triggers when the programmable current limit is reached. This feature allows the vehicle ECU to detect pinching or stalling and be able to overdrive the motor in the event of icing or freezing. Both devices are capable of delivering an absolute maximum supply voltage of 50V and higher gate drive voltage at low VBB, providing better efficiency when using battery power, allowing designers to specify lower cost fets. They even help reduce current in standby to reduce the overall load on the battery.
