Diodes Inc: BCR420U/421U: Current Regulators Simplify the Driving of LEDs

BCR420U and BCR421U constant current regulators provide a simple means of driving low power LED strings. Supporting adjustable currents from 10mA to 350mA allows for platform designs based on a single device to be used across multiple LED strip applications, considerably easing a manufacturer’s overall qualification process. The 40V maximum input rating ensures sufficient headroom for transient supply voltages and allows for LED short failures on long strings. With its low side driver configuration, BCR421U has the added feature of an enable function that can adjust the light output level using a PWM input signal.


  • 10mA ± 10% constant preset current
  • 40V supply voltage
  • Low side control enabling
  • Parallel devices to increase regulated current
  • Up to 350mA adjustable with an external resistor
  • Up to 1W power dissipation in SOT26 (SC-74)
  • Negative temperature coefficient (NTC) reduces IOUT with increasing temperature