By including on-chip Hall commutation and an innovative SPEED control input, Allegro Microsystems evaluation kit for its A4915 three-phase MOSFET controller IC makes it easier to “spin” a motor. The SPEED input takes an analog voltage and generates a pulse-width-modulated output with variable duty cycle. The combination of control interface with on-chip Hall commutation enables efficient control of a brushless dc (BLDC) motor with little or no microprocessing power. Six N-channel power MOSFETs mounted on the kit supply 30 A peak and 20 A nominal run current at room temperature. For larger loads, the A4915 has jumpers that disable the onboard bridge as well as connections to add an external bridge. An onboard 5-V regulator creates the secondary supply for logic inputs. The kit, targeted at the industrial and consumer markets, is available for the 28-pin TSSOP with exposed thermal pad and 28-contact 5- by 5-mm QFN with exposed thermal pad.
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