New quad DMOS full-bridge PWM motor driver IC designed with APFD

20-07-2017 | Allegro | Power

Allegro MicroSystems’ a new quad DMOS full-bridge driver IC is capable of driving up to two stepper motors or four DC motors. Each full-bridge output is rated up to 1.6A and 40V. The A5990 includes fixed off-time PWM current regulators, along with 2- bit nonlinear DACs that allow stepper motors to be controlled in full, half, and quarter steps, and DC motors in forward, reverse, and coast modes. High resolution microstepping control is possible via independent current control reference voltage inputs for each full bridge. The regulator features externally adjustable off-time to adapt the current control to supply voltage and motor parameters - each bridge pair can be adjusted independently. The device also features an APFD option which automatically and continuously adjusts the fast decay portion of the off-time to provide increased step accuracy, lower current ripple, and reduced power dissipation. Alternatively the device can be set to use the Allegro patented mixed decay mode with fixed percent fast decay of 30.1%. Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. To minimise power consumption when not in use, the device can be put into a low current Sleep Mode. Protection features include thermal shutdown with hysteresis, UVLO, OCP and crossover-current protection. Special power-up sequencing is not required. The device is supplied in an EV package, a 6mm × 6mm, 40-pin QFN package with a nominal overall package height of 0.90mm. The package is lead (Pb) free, with 100% matt-tin leadframe plating. It is targeted at the dual axis multiple motor systems including CCTV (pan and tilt), 3D printing, point of sale (receipt and lotto printers), office automation (laser printers, copiers, etc.), medical (diagnostic systems), and the industrial automation market (ATMs and pick and place machines).

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