US1651

UNISONIC TECHNOLOGIES CO., LTD US1651 Preliminary PRIMARY-SIDE REGULATION PWM POWER SWITCH CMOS IC  DESCRIPTION The UTC US1651 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 US1651 operates in primary-side sensing and regulation. Opto-coupler and TL431 could be eliminated. It operates in fixed frequency mode at large load conditions, frequency reduction mode at light/medium load and ‘Extended burst mode’ at No/light load conditions. So that low standby power can be achieved. The UTC US1651 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. SOP-8  FEATURES * Programmable CV and CC regulation * Primary-side sensing and regulation with No TL431 and opto-coupler * Multi-mode operation for high efficiency * Adjustable constant current and output power setting * Power on soft-start time (4ms) * Frequency shuffling and adjustable gate drive greatly improving EMI * ”Extended burst mode control” for improved efficiency and minimum standby design * Built-in leading edge blanking (LEB) * VDD under vo...