This post explains for the DC-DC Controller.
The Part Number is FP6321.
The function of this semiconductor is Sunchronous Buck PWM DC-DC Controller.
The package is SOP 8 Pin type
Preview images :
The FP6321 is designed to drive two N-channel MOSFETs in a synchronous rectified buck topology.
It provides the output adjustment, internal soft-start, frequency compensation networks, monitoring and protection functions into a single package.
The IC operating at fixed 300kHz frequency provides simple, single feedback loop, voltage mode control with fast transient response. The resulting PWM duty ratio ranges from 0-100%. The FP6321 features over current protection. The output current is monitored by sensing the voltage drop across the RDS-ON of the low side MOSFET which eliminates the need for a current sensing resistor. […]
. Operates from +5V or +12V
. Drives Two Low Cost N-Channel MOSFETs
. Fast Transient Response
. Simple Single-Loop Control Design ( Voltage-Mode PWM Control)
. Internal Soft-Start
. Over-Current Fault Monitor
. SOP-8 Package
. RoHS Compliant
. Graphic Card
. Telecomm Equipments
. High Power DC-DC Regulators