Allegro MicroSystems, LLC introduces a new, dual full-bridge driver designed to operate one bipolar stepper or two brush DC motors. Each full bridge uses DMOS power devices with integrated freewheeling diodes. Peak motor current can be limited providing higher efficiency and reduced motor heating. The A4990 includes diagnostic outputs and protection circuits for short circuits, open load, over-temperature and over-voltage and under-voltage lockout Allegro’s A4990 is targeted at both the automotive and industrial markets. Key automotive applications include HVAC actuators, EGR valves, and idle speed control. This device was also designed for harsh environments where stepper or DC actuators are needed for satellite dish or solar panel postioners.
Stepper motors can be driven with full current in either direction in each phase allowing two-phase on, full step operation. DC motors can be driven both clockwise and counter clockwise and in brake mode. A single input turns all bridges off allowing all motors to coast. All control modes can easily be achieved using 3, 4 or 5 outputs from a standard parallel interface of a microcontroller.
The peak motor current can be limited by sense resistor selection providing higher efficiency, reduced motor heating and longer motor life. The outputs are protected from short circuits to supply and ground and low load current detection is included. Chip level protection includes, over temperature shutdown and overvoltage and under-voltage lockout.
The A4990KLPTR-T is supplied in a 20-lead TSSOP power package with an exposed thermal pad (package type LP). This package is lead (Pb) free with 100% matte-tin lead frame plating. It is priced at $1.47 in quantities of 1,000.
Further information about Allegro can be found at www.allegromicro.com.