Using the Buck-Boost topology, the circuit shown in Figure 1 generates a non-isolated constant current (CC) output for driving LEDs. Typical uses include night-lights, neon sign replacements, emergency exit signs or any application utilizing LEDs for lighting

The AC input is rectifi ed and fi ltered by D1, D2, C1, C2, RF1, and RF2. Two diodes improve both line surge withstand (2 kV) and conducted EMI. Resistor RF1 should be a fusible fl ameproof type, whereas RF2 can be fl ameproof only.

Features:

• Universal AC input range – single design worldwide
• Accurate and stable constant current output
• Small size and weight
• Low cost, low component count solution replaces passive capacitor or resistor droppers
• Fail safe topology – protects load
• High effi ciency (>60% at 85 VAC)
• Scalable output power using larger LinkSwitch-TN devices
• Meets EN55022 B EMI limits

Package: PDIP-7

Datasheet: https://www.mouser.com/datasheet/2/328/di74-2297934.pdf