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The PT4107 is a high voltage buck control IC forconstant LED current regulaTIon. It allows efficientoperaTIon of High Brightness (HB) LEDs from voltagesources ranging from 18VDC up to 450VDC or110VAC/220VAC. The PT4107 controls an externalMOSFET at fixed switching frequency from 25 kHZ to200 kHZ. The frequency can be programmed using anexternal resistor. A proprietary peak current controlmethod keeps constant average LED currents for wideinput and output ranges. The output current can beprogrammed from a few milliamps up to more than 1A.The output current on one LED string also can beprogrammed to any value between zero and itsmaximum value by applying an external control voltageat the linear dimming control input of the PT4107.Moreover, PT4107 provides a low-frequency PWMdimming input that can accept an external controlsignal with duty raTIo of 0-100% and a frequency of upto a few kilohertz.Frequency jittering is used to reduce the EMI.
