Allegro Micro公司的 A4447是2A高效率高压降压稳压器,输入电压从8V到50V,输出电压从0.8V到24V可调,输出电流高达2A,外接元件包括钳位二极管,电感和滤波器电容.可广泛应用于UPS,POS和带24V或36V总线的工业应用.本文介绍了A4447的主要特性和优势,方框图以及应用电路图和所推荐的元件表.

    A4447 High Voltage Step Down Regulator

    The A4447 is a 2 A, high efficiency general-purpose buck regulator designed for a wide variety of applications. The output voltage is adjustable from 0.8 to 24 V, based on a resistor divider and the 0.8 V ± 2 % reference. External components include an external clamping diode, inductor, and filter capacitor.

    The off-time is determined by an external resistor to ground. It operates in both continuous and discontinuous modes to maintain light load regulation. An internal blanking circuit is used to filter out transients due to the reverse recovery of the external clamp diode. Typical blanking time is 200 ns.

    This new device is ideal for various end products including applications with 8 to 50 V input voltage range and require up to 2 A output current, such as uninterruptible power supplies, point of sale (POS) applications, and industrial applications with 24 or 36 V bus.

    A4447应用包括:

    Printer power supplies

    Office automation equipment

    POS thermal, laser, photo, and inkjet printers

    Tape drives

    Industrial applications

    A4447特性和优势:

    Wide input voltage range: 8 to 50 V

    Integrated low RDS(on) DMOS switch

    2 A continuous output current

    Adjustable fixed off-time

    Highly efficient

    Adjustable output: 0.8 to 24 V

    Small package with exposed thermal pad

图1.A4447功能方框图

图2.A4447典型应用电路

图3.A4447应用电路

    应用电路所推荐元器件: