The BCR420U and BCR421U monolithically integrate transistors, 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 an 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 is < 40V.
With the low-side control, the BCR421U has an Enable (EN) pin which can be pulse-width modulated (PWM) up to 25kHz by a micro-controller for LED dimming.
With no need for additional external components, this CCR is fully integrated into a 2x2x0.6mm package (U-DFN2020-6) minimizing PCB area, off-board height, and component count.
Edge Lighting Strips
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 1.7W in U-DFN2020-6 Package
0.6mm Height for Low-profile Edge Lighting
Low-Side Control Enabling PWM Input < 25kHz (BCR421U)
Negative Temperature Coefficient (NTC) Reduces IOUT with Increasing Temperature