UC3845ST SOIC8

The L6565 is a current-mode primary controller IC, specifically designed to build offline Quasi-resonant ZVS (Zero Voltage Switching at switch turn-on) flyback converters. Quasi-resonant operation is achieved by means of a transformer demagnetization sensing input that triggers MOSFET's turn-on. Converter's power capability variations with the mains voltage are compensated by line voltage feedforward. At light load the device features a special function that automatically lowers the operating frequency still maintaining the operation as close to ZVS as possible. In addition to very low start-up and quiescent currents, this feature helps keep low the consumption from the mains at light load and be Blue Angel and Energy Star compliant. The IC includes also a disable function, an on-chip filter on current sense, an error amplifier with a precise reference voltage for primary regulation and an effective two-level overcurrent protection.

L6561 is the improved version of the L6560 standard Power Factor Corrector. Fully compatible with the standard version, it has a superior performant multiplier making the device capable of working in wide input voltage range applications (from 85V to 265V) with an excellent THD. Furthermore the start up current has been reduced at few tens of mA and a disable function has been implemented on the ZCD pin, guaranteeing lower current consumption in stand by mode. Realised in mixed BCD technology, the chip gives the following benefits: micro power start up current 1% precision internal reference voltage (T _j = 25°C) Soft Output Over Voltage Protection no need for external low pass filter on the current sense very low operating quiescent current minimises power dissipation The totem pole output stage is capable of driving a Power MOS or IGBT with source and sink currents of ±400mA. The device is operating in transition mode and it is optimised for Electronic Lamp Ballast application, AC-DC adaptors and SMPS.

The L78 series of three-terminal positive regulators is available in TO-220, TO-220FP, D²PAK and DPAK packages and several fixed output voltages, making it useful in a wide range of applications. These regulators can provide local on-card regulation, eliminating the distribution problems associated with single point regulation. Each type embeds internal current limiting, thermal shut-down and safe area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1 A output current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltage and currents.