The BCR420U/BCR421U monolithically integrates a transistor, diodes and resistors to function as a Constant Current Regulator (CCR) for linear LED driving. The device regulates with a preset 10mA nominal that can be adjusted with external resistor up to 350mA. It is designed for driving LEDs in strings and will reduce current at increasing temperatures to self-protect. Operating as a series linear CCR for LED string current control, it can be used in multiple applications, as long as the maximum supply voltage to the device < 40V.
With the low-side control, the BCR421U has an Enable (EN) pin which can be pulse-width modulated (PWM) up to 10 kHz by a micro controller for LED dimming.
With no need for additional external components, this CCR is fully integrated into a SOT26 minimizing PCB area and component count.
Constant Current Regulation (CCR) in:
Automotive Interior Lighting
Signage, Advertising, Decorative and Architectural Lighting
Retail Lighting in Fridges, Freezer Cases and Vending Machines
LED Constant Current Regulator using NPN Emitter-Follower with Emitter Resistor to Current Limit
Iout = 10mA ± 10% Constant Current (Preset)
Iout up to 350mA adjustable with an External Resistor
Vout = 40V Supply Voltage
Pd up to 1W in SOT26 (SC-74)
Negative temperature coefficient (NTC) reduces IOUT with increasing temperature
Parallel Devices to Increase Regulated Current
Totally Lead-Free & Fully RoHS Compliant
Halogen and Antimony Free. “Green” Device
Qualified to AEC-Q101 Standards for High Reliability