RT8458D

® RT8458D High Voltage, High Efficiency, Constant Current PWM Buck Controller for LED Lighting General Description The RT8458D is a PWM controller with an internal high side gate driver. Because of the Buck topology, the input voltage for the Buck system is only limited by the voltage rating of the external MOSFET. It is used for step down converters by well controlling the external MOSFET and regulating a constant output current. The output duty cycle of the RT8458D can be up to 100% for wider input voltage application. The RT8458D also features a 160kHz fixed frequency oscillator, an internal −220mV precision reference, and a PWM comparator with latching logic. The accurate output LED current is achieved by an averaging current feedback loop and the LED current dimming can be easily controlled via the ACTL pin. The RT8458D also has multiple features to protect the controller from fault conditions, including Under Voltage Lockout (UVLO), Over Current Protection (OCP) and Over Voltage Protection (OVP). Additionally, to ensure the system reliability, the RT8458D is built with the thermal protection function. The RT8458D is housed in a TSOT-23-6 package. Thus, the components in the whole LED driver system can be made very compact. Features  Low Cost and Efficient Buck Converter Solution  Input Voltage Depends On External MOSFET  Programmable Constant LED Current  Dimmable LED Current by ACTL  100% Maximum Duty Cycle  160kHz Fixed Switching Frequency  Output LED String...