The A3985 is a flexible dual full-bridge gate driver suitable for driving a wide range of higher power industrial bipolar 2-phase stepper motors or 2-phase brushless DC motors. It can also be used to drive two individual torque motors or solenoid actuators. Motor power is provided by external N-channel power MOSFETs at supply voltages from 12 to 50 V.
全数字控制由两个串联可访问的寄存器提供，允许编程关闭时间，空白时间，死区时间，混合衰减比率，同步整流，主时钟源选择和分割比和空闲模式。所有内部定时均来自主时钟，可以在片上生成或由外部时钟提供，例如主控制器的系统时钟。可编程分频器允许各种外部系统时钟频率。
The internal fixed off-time PWM current-control timing is programmed via the serial interface to operate in slow, fast, and mixed current-decay modes. The desired load-current level and direction is set via the serial port with a direction bit and two 6-bit linear DACs in conjunction with a reference voltage. The seven bits of control allow maximum flexibility in torque control for a variety of step methods, from microstepping to full-step drive. Load current in the external power MOSFET full-bridges is set in 1.56% increments of the maximum value.
The above-supply voltage required for the high-side N-channel MOSFETs is provided by a bootstrap capacitor. Efficiency is enhanced by using synchronous rectification and the power FETs are protected from shoot-through by integrated crossover-control and programmable dead time.
我n addition to crossover current control, internal circuit protection provides thermal shutdown with hysteresis and undervoltage lockout. Special power-up sequencing is not required. This component is supplied in a 38-pin TSSOP (package LD) with 100% matte tin leadframe plating.
