Motor Controller ICs Feature Commutation Logic

Jan 9, 2008 12:24 PM

From Allegro MicroSystems (www.allegromicro.com) come two automotive-grade (temperature and voltage rated) three-phase BLDC motor controller ICs. These control ICs simplify the system design and lower system cost by integrating the commutation logic on-board.

If desired, the Hall sensor inputs can be driven directly by a microprocessor, which makes the A3930 and A3931 key components in a robust back EMF (sensorless) solution. These controllers are primarily targeted at automotive Hall commutated three-phase motors driven by discrete/external n-channel MOSFETs.

An on-chip commutation decoder and state machine reads the inputs of three Hall sensor inputs (or IO outputs from a microprocessor). The IC then outputs the correct gate drive signals that control six (three high-side, three low-side) external NMOS MOSFETs, which drive the three-phase BLDC motor. Other key features are a 5 V supply for Hall sensors, integrated charge pump, operation over a wide battery voltage range (5.5 V to 50 V), and extensive diagnostics.

The A3930 and A3931 are offered in a 48L eLQFP package. They are both priced at $3.12 in quantities of 1000.

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