Texas Instruments LM3485MM/NOPB
The LM3485 is a high-efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, low-cost, switching buck regulator for a wide range of applications. The hysteretic control architecture provides for simple design without any control-loop stability concerns using a wide variety of external components. The PFET architecture also allows for low component count as well as ultralow dropout, 100% duty cycle operation. Another benefit is high efficiency operation at light loads without an increase in output ripple.
Current limit protection is provided by measuring the voltage across the RDS(ON) of the PFET, thus eliminating the need for a sense resistor. The cycle-by-cycle current limit can be adjusted with a single resistor, ensuring safe operation over a range of output currents.

德克萨斯仪器lm3485mm / NOPB
是一种高效的lm3485 PFET开关稳压控制器，可以用来快速地开发一个小型、低成本、开关降压稳压器应用范围广。迟滞控制架构提供了简单的设计，没有任何控制回路的稳定性问题，使用各种各样的外部元件。PFET架构还允许低元件数量以及超差，100%工作周期操作。另一个好处是在轻负载下高效率运行而不增加输出纹波。
限流保护是通过测量电压，RDS提供的PFET（上），从而消除了检测电阻的需要。一个周期的电流限制可以用一个电阻器来调节，确保在一系列输出电流下的安全运行。