The A4979 is a flexible microstep motor driver with a built-in converter for easy operation. It is a single-chip solution capable of driving bipolar stepper motors in full-step, half-step, quarter, and 16/16 step modes with operating voltages and currents up to 50 V and 1.5 A. The A4979 can be controlled with simple step and direction inputs or from an SPI-compatible serial interface that can also be used to program a variety of integrated functions and read diagnostic information.
The current regulator is programmed to operate with fixed downtime or fixed frequency PWM and can reduce the motor's audible noise and improve step accuracy with multiple attenuation modes. In addition, phase ammeters can be programmed with serial interfaces to establish unique microstep current distributions for specific applications, further improving motor performance.
The motor phase current is controlled via a DMOS fully bridged unit using synchronous rectification to reduce power dissipation. When switching between high-side and low-side drives, internal circuitry and timers prevent transconductivity and breakdown.
The output has short-circuit protection. In addition, it features low load current and stall rotor detection. Chip-level protection includes: high and low temperature warning, over-temperature shutdown, and undervoltage lockout. The A4979 is available in a 28-pin TSSOP power pack package with a heatsink (package type LP) on the outside. Lead-free package with 100% matte tin plated lead frame.
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典型应用达 1.5 A，50 V
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低 RDS (On)输出，0.5 Ω汲取电流，典型
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自动电流衰减模式检测/选择
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混合、快速及慢速电流衰减模式
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低功耗同步整流
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内部 UVLO 及热关闭电路
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交叉电流保护
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短路及开路负载诊断
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高温和低温警告
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失速检测功能
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兼容 SPI 或简易的步进和方向运动控制
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通过兼容 SPI 的串行接口实现了高度可配置性能