Fairchild Power Switch Improves Off-Line Power Supply Designs
Fairchild Semiconductor has developed what it describes as the only power switch in the industry that integrates drain-current sensing in a 650V internal avalanche-rugged SenseFET, reducing power dissipation and improving reliability by shortening the over-current time delay to less than 200ns.
This FPS™ power switch for off-line power supplies up to 60W (for universal ac input) – the FSGM0565R – achieves what is described as exceptional standby power consumption in a 66 kHz flyback converter: 120mW at 265Vac in with 25mW of load. This is enabled by the SenseFET, a high-voltage startup circuit that turns off the startup resistor, and "soft burst" operation in standby, saving 30mW and preventing the converter from generating audible noise.
Many protection features are built-in, all with auto-restart, to reduce component count in the power supply, providing designers with greater value and higher reliability. These include overload protection, over-voltage protection, abnormal over-current protection, internal thermal shutdown with hysteresis, output short protection and under-voltage lockout. The combination of low component count and high reliability makes this power switch attractive for many applications including LCD TVs and monitors – especially four-lamp LCD monitors.
Other advanced features include a wide supply-voltage range (12 to 24Vdc), built-in 15ms soft-start and enhanced lightning surge immunity.
The FSGM0565R, available in a 6-lead TO-220F package is priced (each, 1k pcs.) at US $1.00 with a delivery of 6-8 weeks.