Power Factor Controllers

The MC34261/MC33261 are active power factor controllers specifically designed for use as a preconverter in electronic ballast and in off?line power converter applications. These integrated circuits feature an internal startup timer, a one quadrant multiplier for near unity power factor, zero current detector to ensure critical conduction operation, high gain error amplifier, trimmed internal bandgap reference, current sensing comparator, and a totem pole output ideally suited for driving a power MOSFET.

Also included are protective features consisting of input undervoltage lockout with hysteresis, cycle?by?cycle current limiting, and a latch for single pulse metering. These devices are available in dual?in?line and surface mount plastic packages.

? Internal Startup Timer

? One Quadrant Multiplier

? Zero Current Detector

? Trimmed 2 Internal Bandgap Reference

? Totem Pole Output

? Undervoltage Lockout with Hysteresis

? Low Startup and Operating Current

? Pinout Equivalent to the SG3561

? Functional Equivalent to the TDA4817