特点：

• 用于N沟道MOSFET的双H桥门极驱动
• 同步整流
• 交叉导通保护
• 可调节的混合衰减模式
• Eaststepper TM 接口
• 集成正弦DAG电流参考
• 固定关断时间的PWM电流控制
• 12~50V电源电压控制

    A3986是集成细分译码器的双H桥门极驱动器，可用于驱动宽范围的大功率双极性2相步进电机。外部的N沟道功率MOSFET驱动电机工作在12V~50V电源电压下。

    A3986包括的两个正弦DAG产生参考电压，用于两个独立的固定关断时间的PWM电流控制器，来调节外部功率MOSFET H桥的电流。

    Easystepper TM接口方式使细分非常简单，仅需要细分和方向输入即可实现细分控制，可工作在整步，半步，四分之一步，十六分之一步下。固定关断时间的调节器可控制慢速，快速或混合衰减模式，来减少电机噪声，提升细分控制准确度，和减少功耗。

A3986
Dual Full-Bridge MOSFET Driver with Microstepping Translator

Features

• 2-wire step and direction interface
• Dual full-bridge gate drive for N-channel MOSFETs
• Operation over 12 to 50 V supply voltage range
• Synchronous rectification
• Cross-conduction protection
• Adjustable mixed decay
• Integrated sinusoidal DAC current reference
• Fixed off-time PWM current control

Description

The A3986 is a dual full-bridge gate driver with integrated microstepping translator suitable for driving a wide range of higher power industrial bipolar 2-phase stepper motors (typically 30 to 500 W). Motor power is provided by external N-channel power MOSFETs at supply voltages from 12 to 50 V.

This device contains two sinusoidal DACs that generate the reference voltage for two separate fixed-off-time PWM current controllers. These provide current regulation for external power MOSFET full-bridges.

Motor stepping is controlled by the two-wire step and direction interface, providing complete microstepping control at full-, half-, quarter-, and sixteenth-step resolutions. The fixed-off time regulator has the ability to operate in slow-, mixed-, or fast-decay modes, which results in reduced audible motor noise, increased step accuracy, and reduced power dissipation.

The translator is the key to the easy implementation of this IC. Simply inputting one pulse on the STEP input drives the motor one step (full, half, quarter, or sixteenth depending on the microstep select input). There are no phase-sequence tables, high frequency control lines, or complex interfaces to program. This reduces the need for a complex microcontroller.

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.

In 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 an 38-pin TSSOP (package LD). The package is lead (Pb) free, with 100% matte tin leadframe plating.

Functional Block Diagram