The common off-line LED lighting system consists of either isolated or non-isolated topologies with constant current output to light up LED strings. The most popular topology used in the market now is a single stage LED driver features high power factor correction (PFC). By using single stage approach, the system cost is cheap, but the LED current also suffers from high current ripple which can cause flicker due to the nature of high power factor correction feature.
The RT7315A as a second stage circuit is a flicker filter designed to greatly reduce the current ripple commonly seen at the output of either the isolated or non-isolated single-stage constant current driver with PFC. The control loop inside the RT7315A regulates the LED current with minimized 100Hz/120Hz current ripple.
The RT7315A also equips with several protection features as follows. (1) Over temperature protection (OTP) (2) LED short circuit protection (3) LED open circuit protection (4) LED hot plug protection. The RT7315A system circuit is simple and small. The BOM cost is cheap and the required PCB space is tiny.