The A3968 controls two DC motors in both directions. The device includes two all-electric bridges capable of continuously outputting ±650 mA and operating voltages up to 30 volts. Motor winding current can be controlled through internal fixed frequency, pulse-width modulation (PWM), and current control circuitry. The user can set the peak load current limit by selecting the reference voltage and current sense resistor.
Users can set a fixed frequency pulse duration by selecting an external RC timing network. Capacitors in RC timing networks can also determine a user-selectable blank window that prevents false triggering of PWM current control circuits during switching.
To reduce chip power dissipation, the full-bridge power output has been optimized to accommodate low saturation voltages. The charger driver features Allegro's® patented Satlington ® output structure. Satlington outputs combine the low voltage drop of saturated transistors with Darlington's high peak current capacity.
For each bridge, the Input A and Input B ports determine the load current polarity by activating the appropriate power and sink driver pairing. When the logic is low applied in the bridge "input", the brake function is enabled. In braking mode, the two power drives are turned off and the two current drivers are turned on, so the motor is dynamically braked. When logic high is applied in the two "inputs" of the bridge, all output drivers are disabled.
No special power-up sequencing is required. Internal current protection includes overheating shutdown with delay, grounding clamp flyback diode and crossover current protection.
The A3968 is available in a 16-pin plastic SOIC package with two pins connected to the underpad via an internal fuse for enhanced heat dissipation. These pins are at ground potential and do not require electrical insulation. The device is lead-free and features a 100% matte tin plated pin frame.
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±650 毫安连续输出电流
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30 伏特输出电压额定值
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内部固定频率 PWM 电流控制
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Satlington® 灌电流驱动器
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制动模式
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用户可选择的空白窗口
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内部接地钳位和反激二极管
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内部过热关机电路
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交叉电流保护和 UVLO 保护