BD9528MUV is a 2-channel switching regulator controller with high output current which can achieve low output voltage (1V to 5.5V) from a wide inpute voltage range (5.5V to 28V). High efficiency for the switching regulator can be realized by utilizing an external N-MOSFET power transistor. A new technology calld H3Reg (High speed, High efficiency, High Performance) is a Rohm proprietary control method to realize ultra high transient response against load change. SLLM (Simple Light Load Mode) technology is also integrated to improve efficiency in ligh load mode, providing high efficiency over a wide load range. For protection and ease of use, 2-Channel LDO (5V/3.3V (total 100mA)), the soft start function, variable frequency function, short circuit protection function with timer latch, over voltage protection, and Power good function are all built in. This switching regulator is specially designed for Main Power Supply of laptop PC.