The A3918 from Allegro MicroSystems Europe is a new full-bridge DC motor driver IC capable of a continuous output current of 1A and operating voltages from 2.5 to 9V. An internal PWM current reference allows the user to select the peak chop current using only a resistor.
The new device is the latest addition to Allegro’s low-voltage family of motor drivers, providing a single full-bridge option to complement the dual full-bridge capability found in the company’s existing family of devices. The single supply and simple logic interface makes this an ideal product for applications involving single-cell lithium-ion batteries.
The A3918 has a unique design which incorporates a two-stage charge pump that ensures that the driver has a low output resistance over the entire supply range from 9V down to 2.5V. This feature dramatically improves battery life when battery voltages are low because the switches do not become highly resistive due to reduced gate drive.