GENERAL DESCRIPTION
HM274X family is a high performance Switch Mode Power Supply Switcher for low power off-line application with minimum components in typical buck solution. This family has built-in high break down voltage MOSFET to withstand high surge input.
Unlike conventional PWM control, there’s no fixed internal clock in HM274X family to trigger the GATE driver, the switching frequency is changed according to the load conditon. The multi mode PWM control is integrated to simplify circuit design and achieve good line and load regulation without audio noise generated. The peak current limit changes according to the real load condition for low standby power in no load.
HM274X integrates functions and protections of Under Voltage Lockout (UVLO), Cycle-by-cycle Current Limiting (OCP), Output OVP, On-chip Thermal Shutdown, Over Load Protection (OLP), VDD OVP with Auto Recovery Mode Protection, etc.

FEATURES
● Integrated with 650V Pow er MOSFET and HV Startup Circuit
● Multi Mode Control with Audio Noise Free Operation
● Supports Buck and Buck-Boost Topologies
● Default 12V Output with FB floated
● Less than 50mW Standby Power
● Green Mode Operation for High Efficiency
● Good Line and Load Regulation
● Built-in Soft Start
● Build in Protections:
● Over Load Protection (OLP)
● Cycle-by-Cycle Current Limiting (OCP)
● Output OVP
● VDD OVP, UVLO & Clamp
● Available with SOP-8 Package