The HV9921 is a pulse width modulated (PWM) high-efficiency LED driver control IC. It allows efficient operation of LED strings from voltage sources ranging up to 400VDC. The HV9921 includes an internal high voltage switching MOSFET controlled with fixed off-time (TOFF) of approximately 10.5μs. The LED string is driven at constant current, thus providing constant light output and enhanced reliability. The output current is internally fixed at 20mA for HV9921. The peak current control scheme provides good regulation of the output current throughout the universal AC line voltage range of 85 to 265VAC or DC input voltage of 20 to 400V.

  Constant output current: 20mA

  Universal 85 - 265VAC operation

  Fixed off-time buck converter

  Internal 475V power MOSFET