IR’s smallest PFC boost IC in a 5-pin SOT-23 package
The IRS2505 is a control IC for boost-type PFC circuits operating in critical-conduction mode. The IC incorporates a free-running frequency oscillator with on-time and off-time control of the boost power MOSFET without the need for a secondary winding. Also included in the design is over-voltage protection of the DC bus and cycle-by-cycle over-current protection of the power MOSFET. Micro-power start-up current and an internal 20.8 V zener clamp at VCC are provided to simplify the external VCC supply circuitry.