Dual full-bridge motor driver IC for automotive/harsh environment applications

September 25, 2013 // By Graham Prophet
A4990 from Allegro MicroSystems Europe is a dual full-bridge driver IC designed to operate one bipolar stepper or two brush DC motors in automotive and harsh environment industrial applications.

Each full bridge in the new device uses DMOS power devices with integrated freewheeling diodes. Peak motor current can be limited to provide higher efficiency and reduce motor heating. The driver IC is targeted at both the automotive and the industrial markets. Key automotive applications include HVAC actuators, EGR (exhaust gas recirculation) valves, and idle speed control. It is also designed for harsh environments where stepper or DC actuators are needed: for example, in satellite dish or solar panel positioning systems.

The A4990 enables stepper motors to 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 anticlockwise, and in brake mode. A single input turns all bridges off, allowing all motors to coast. All control modes can easily be achieved using three, four or five outputs from a standard parallel interface of a microcontroller.

The A4990 is designed for typical applications requiring up to 800 mA and 28V, and has 3.3V and 5V compatible inputs. The peak motor current can be limited by sense resistor selection to provide higher efficiency, reduced motor heating and longer motor life.

Outputs are protected from short circuits to supply and ground, and low-load current detection is included. Chip-level protection includes overtemperature shutdown and overvoltage and undervoltage lockout. The A4990KLPTR-T is supplied in a 20-lead TSSOP power package with an exposed thermal pad (package type LP).

Allegro Microsystems; www.allegromicro.com/en/Products/Motor-Driver-And-Interface-ICs/Bipolar-Stepper-Motor-Drivers/A4990.aspx