Allegro MicroSystems, has introduced a portfolio of 80V motor drivers for 48V automotive systems.

• AMT49100 / AMT49101

       safety-enhanced three-phase gate drivers for electric power steering and other safety-critical systems

• AMT49502

       safety half-bridge gate driver with actuators and solid-state relays

• A89503

       safety half-bridge gate driver with independent high-side and low-side output loads for floating loads, such as seat heaters and catalytic heaters

• A89500

       100V high-power half-bridge gate driver in DFN package for distributed systems, 48V power inverters, golf carts, and e-bikes

“These automotive gate drivers were developed on an ISO 26262 compliant design process,” according to the company. “Allegro’s ASIL gate drivers have over 20 diagnostic features included, allowing the customer to diagnose, verify, and act against system faults.”

AMT49100 (pictured), for example, is a three phase driver for six n-channel mosfets for loads including brushless dc motors.

A fixed-frequency buck converter is included for regulated gate drive over the full 10 – 80V supply range.

A bootstrap capacitor is used to hold the above-battery supply required for high-side n-channel mosfets, with bootstrap power coming from the output, or from an in-built charge-pump – the latter allowing the output mosfets to operate over the full 0-100% PWM duty cycle range.

Through the three phase outputs, motors can be driven with block commutation or sinusoidal excitation.

Output mosfets are protected from shoot-through by integrated crossover control and optional programmable dead time.

Integrated diagnostics provide indication of multiple internal faults, system faults, power bridge faults “and can be configured to protect the power mosfets under most short-circuit conditions,” according to the company. “For safety-critical systems, the integrated diagnostic operation can be verified under control of the serial interface.”

In addition to providing access to the bridge control, and diagnostic information, the serial interface is also used to alter programmable settings such as dead time, Vds threshold and fault blank time.