原标题：Allegromicro A4980汽车步进马达驱动方案

　　Allegromicro公司的 A4980是可编程的汽车微步进马达驱器,驱车电压高达28V,驱动电流±750 mA.设计用于以满步,半步,1/4步和1/16步驱动双向马达.器件内部集成了OVLO, UVLO和热关断电路,主要用在汽车步进马达,引擎管理和头灯定位.本文介绍了A4980主要特性和优势,功能方框图, 串行和并行接口控制应用电路图.

　　The A4980 is a flexible microstepping motor driver with built-in translator for easy operation. It is a single-chip solution, designed to operate bipolar stepper motors in full-, half-, quarter- and sixteenth-step modes, at up to 28 V and ±750 mA. The A4980 can be controlled by simple Step and Direction inputs, or through the SPI-compatible serial interface that also can be used to program many of the integrated features and to read diagnostic information.

　　The current regulator can be programmed to operate in fixed off-time or fixed frequency PWM, with several decay modes to reduce audible motor noise and increase step accuracy. In addition the phase current tables can be programmed via the serial interface to create unique microstep current profiles to further improve motor performance for specific applications.

　　The current in each phase of the motor is controlled through a DMOS full bridge, using synchronous rectification to improve power dissipation. Internal circuits and timers prevent crossconduction and shoot-through, when switching between highside and low-side drives.

　　The outputs are protected from short circuits, and features for low load current and stalled rotor detection are included. Chip-level protection includes: hot and cold thermal warnings, overtemperature shutdown, and overvoltage and undervoltage lockout.

　　The A4980 is supplied in a 28-pin TSSOP power package with an exposed thermal pad (package type LP). This package is lead (Pb) free with 100% matte-tin leadframe plating.

　　A4980主要特性和优势:

　　• Typical application up to ±750 mA, 28 V

　　• Low RDS(on) outputs, 0.5 Ω source and sink, typical

　　• Automatic current decay mode detection/selection

　　• Mixed, Fast, and Slow current decay modes

　　• Synchronous rectification for low power dissipation

　　• Internal OVLO, UVLO, and Thermal Shutdown circuitry

　　• Crossover-current protection

　　• Short circuit, and open load diagnostics

　　• Hot and cold thermal warning

　　• Stall detect features

　　• SPI-compatible or simple Step and Direction motion control

　　• Highly configurable via SPI-compatible serial interface

　　A4980应用:

　　• Automotive stepper motors

　　• Engine management

　　• Headlamp positioning

　　图1. A4980功能方框图

　　图2. A4980串行接口控制应用电路图

　　图3. A4980并行控制应用电路图