L6668

AC DC Converters, Offline Switchers Overview

The L6668 is a current-mode primary controller IC designed for single-ended flyback converters. It operates at a fixed switching frequency of 100kHz and supports a maximum duty cycle of 70%. The device features an on-board high-voltage start-up circuit with a startup voltage of 13.5V and a supply voltage range of 9.4V to 22V. It employs load-dependent control, transitioning from fixed-frequency operation at heavy loads to frequency foldback at light loads, and burst-mode at no-load. The IC includes programmable soft-start, slope compensation, and multiple protection mechanisms including latched disable for overvoltage and overtemperature conditions.

AC DC Converters, Offline Switchers Feature Summary

• Load-dependent current-mode control providing fixed-frequency operation at heavy loads, frequency foldback at light loads, and burst-mode at no-load to minimize mains consumption.
• Integrated interface with PFC controllers to enable pre-regulator shutdown when load falls below a threshold, ensuring compliance in power-factor-corrected systems.
• Robust protection suite featuring two-level OCP, latched disable for OVP/OTP, leading edge blanking for noise immunity, and slope compensation for stability at high duty cycles.

AC DC Converters, Offline Switchers Applications

• Offline AC-DC converters requiring compliance with Blue Angel, Energy Star, and EU Code of Conduct energy saving regulations
• Power-factor-corrected (PFC) systems utilizing the dedicated interface for pre-regulator management
• Standby power applications demanding low quiescent current and improved standby performance

AC DC Converters, Offline Switchers Procurement Notes

Verify the specific package variant, as the L6668 is available in SO16L packages. Confirm that the ordering suffix matches the required tape-and-reel or cut-tape configuration. Ensure the component meets RoHS3 standards and REACH requirements for your target market. Cross-reference the manufacturer part number with official STMicroelectronics documentation to confirm active status and availability before finalizing procurement.

AC DC Converters, Offline Switchers Selection Notes

Select the L6668 for applications requiring efficient light-load performance through its advanced frequency foldback and burst-mode capabilities. The integrated high-voltage start-up reduces external component count. Consider this controller for designs needing precise current-mode control with slope compensation for duty cycles exceeding 50%. The inclusion of a PFC interface makes it suitable for complex multi-stage power supplies.

AC DC Converters, Offline Switchers Part Context

The L6668 belongs to STMicroelectronics' portfolio of smart primary controllers for offline power conversion. It utilizes Multipower BCD technology to integrate high-voltage start-up and precision analog controls within a compact SO16 package. This series targets high-efficiency power supplies that must adhere to stringent global energy efficiency standards while maintaining stable operation across varying load conditions.

AC DC Converters, Offline Switchers Replacement Considerations

Consult official STMicroelectronics substitution guides for verified alternatives. No public substitute part numbers are confirmed in the provided data.