QX5278 is a buck-boost constant-current LED driver chip, especially suitable for LED light implementations powered by lithium batteries or triple-cell batteries. When the supply voltage is smaller than the break-over voltage of the LED light, QX5278 functions in boost mode; when the supply voltage is higher than the break-over voltage of the LED light, QX5278 functions in buck mode.

The working voltage of QX5278 is 2.4V – 5.5V. Its operating current is less than 500 mA, its efficiency can reach up to 90% and its current accuracy is within 5%. The LED current is determined by external resistance. QX5278 also provides a 2.4V under voltage shutdown protection, a 5V open circuit protection and output short circuit protection. QX5278 uses SOP8 packaging.