The A3985 is a flexible, dual-way, full-bridge gate driver suitable for driving a wide range of high-power industrial bipolar 2-phase stepper motors or 2-phase brushless DC motors. It can also be used to drive two independent torque motors or solenoid drives. Motor power is provided by an external N-channel power MOSFET with a supply voltage of 12 to 50 volts.
Two serial registers provide full digital control for programming shutdown time, blanking time, downtime, mixed attenuation coefficient, synchronous rectification, master clock source selection, scale ratio, and no-load mode. All internal time can be obtained from the main clock, which can be generated by the chip, or provided by an external clock, such as the main controller's clock. Programmable splitters support a wide range of external system clock frequencies.
The built-in fixed-shutdown time PWM current control timing can be programmed via a serial interface, allowing for low-speed, fast, and fixed current decay modes. The desired load current level and direction can be set via a serial port with one direction bit and two 6-position linear DACs, as well as a reference voltage. The 7-position controller enables flexible torque control to support different stepping modes, from micro-step to full-step drives. The load current within the full bridge of the external power MOSFET is set in 1.56% increments of the maximum.
The bootstrap capacitors provide the supply voltage required for these high-end N-channel MOSFETs. Efficiency is increased by applying synchronous rectification, and integrated crossover control and programmable downtime save power FETs from breakdowns.
In addition, cross-current control and internal circuit protection can provide overheating power loss (with hysteresis function) and undervoltage lockout protection. No special power-up sequencing is required. The device is available in a 38-pin TSSOP package (package LD) with 100% matte tin plating on the pin frame.
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串行接口适用于全数字式控制
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N 通道 MOSFET 双路全桥门极驱动器
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双路 6 位 DAC 电流给定
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12 至 50 伏特的电源电压范围内工作
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同步整流
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交叉传导保护
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可调混合衰减
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固定停机时间 PWM 电流控制
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低电流空载模式