Product category:
Power Supply ICs and Controllers
News Release from: Allegro MicroSystems Europe | Subject: A3949
Edited by the Electronicstalk Editorial
Team on 16 March 2004
PWM controller provides flexible motion
The A3949 is a DMOS full-bridge motor driver integrated circuit designed for the PWM (pulsewidth-modulated) control of DC motors.
The A3949 is a DMOS full-bridge motor driver integrated circuit designed for the PWM (pulsewidth-modulated) control of DC motors The new device is capable of peak output currents of up to +/-2.8A and operating voltages up to 36V, and has low-on-resistance outputs: typically 0.68ohm for the source driver and 0.576ohm for the sink driver
This article was originally published on Electronicstalk on 30 Aug 2000 at 8.00am (UK)
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Phase and enable input terminals are provided for controlling the speed and direction of the motor with externally applied PWM control signals.
Internal synchronous rectification control circuitry is provided to reduce power dissipation during PWM operation.
A sleep mode, implemented via a logic low on a dedicated input terminal, is provided to minimise power consumption when the A3949 is not in use.
This disables much of the internal circuitry, including the low-side gate supply and the charge pump.
A braking function is implemented by driving the device in slow decay mode via the mode pin, and applying an enable-chop command.
Because it is possible to drive current in both directions through the DMOS switches, this configuration effectively shorts out the motor-generated back EMF.
Internal circuit protection includes thermal shutdown with hysteresis, undervoltage monitoring of load supply and charge-pump voltages, and crossover current protection.
The A3949 is supplied in a choice of two power packages, a 16-lead plastic SOIC with a copper batwing tab (suffix LB), and a low-profile (1.1mm) 16-lead TSSOP (suffix LP) with exposed power tab.
Operating temperature range is -20 to +85C.
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