PWM-FF (fixed frequency) Flyback ICs

Infineon’s 5^th generation fixed frequency flyback ICs are available in both 100kHz and 125kHz switching frequency and offer high integration of performance and protection features. For a fast start-up performance, the FF PWM controller combines a high-voltage superjunction MOSFET with the internal current regulator to operate the start-up sequence in a safe and rapid manner. This also allows for an easy implementation of brown-in protection. Furthermore, the 5^th generation flyback converter can detect abnormal line-input conditions and has an improved in-system production as well as enhanced overtemperature protection (OTP) to improve operational fault handling.

Improved efficiency performance

To further enhance the overall system efficiency, the ICE5xSAG has a digital frequency reduction operation implemented, allowing for a better performance during light load, and with the enhanced active burst mode (ABM) lowest standby power of <100mW can be reached. This eco mode allows the system to reduce switching losses and to increase efficiency, especially at mid- and light-load conditions. In addition, for low AC line-input operation, CCM (continuous current mode) operation has been incorporated. Therefore, the PWM controller IC achieves lower conduction losses, which makes it possible to reach a higher efficiency level and enables meeting the international regulatory standards.

BOM savings and ease of design

To simplify the design of the power supply, the 5^th generation fixed frequency flyback IC controllers have an integrated error amplifier, supporting direct feedback from the primary output with reduced complexity and fewer components. This approach helps to reduce BOM count and cost of a non-isolated flyback design. To minimize interruption to system operation, all protection modes are implemented with auto-resume to enhance user experience.

Applications

Infineon’s 5^th generation fixed frequency PWM controllers ICE5xSAG are targeted for SMPS applications such as auxiliary power supplies for home appliances (e.g. AUX in washing machines, refrigerators and air-condition), set-top-boxes, LCD/LED monitors, and general-purpose power supplies up to a maximum output power of 60W.