DESCRIPTION

The UTC US3701 is a primary control switch mode charger and

adapter applications. The controlled variable is transferred by an

auxiliary winding from the secondary to the primary side. The

device integrates PWM controller to enhance the performance of

discontinuous conduction mode (DCM) flyback converters.

The UTC US3701 operates in primary-side sensing and

regulation. Opto-coupler and TL431 could be eliminated. It also

provides off-time modulation to linearly decrease PWM frequency

under light-load conditions so that low standby power can be

achieved.

The UTC US3701 achieves high precision CV/CC regulation

and high power efficiency. It offers comprehensive protection

coverage with auto-recovery features including Cycle-by-cycle

current limiting, VDD over voltage protection, VDD clamp, OTP,

leading edge blanking, VDD under voltage lockout, etc.