Three-phase brushless motor controller separates the mosfets

Allegro MicroSystems has a three-phase brushless BLDC motor controller for use with N-channel external power mosfets.

Allegro

AMT49413

The AMT49413 can be used as part of three-phase motor drive systems with maximum supply voltages up to 50V.

One feature of the devices is a charge pump regulator that provides adequate (>10V) gate drive for battery voltages down to 7V, and allows the device to operate with a reduced gate drive at supply voltages down to 5.5V.

A bootstrap capacitor is used to provide the above-battery supply voltage required for N-channel mosfets.  An internal charge pump for the high-side drive allows for DC (100% duty cycle) operation.

Internal fixed-frequency PWM current control circuitry can be used to regulate the maximum load current. The peak load current limit is set by the selection of an input reference voltage and external sensing resistor.

The PWM frequency is set by a user-selected external RC timing network.

The PWM input can also be used to provide speed and torque control, allowing the internal current control circuit to set the maximum current limit.  Efficiency is enhanced by using synchronous rectification.

The AMT49413 is supplied in a 48-pin QFN with exposed thermal pad. This is a small footprint (7 × 7mm) power package.


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