Diodes Incorporated extends its family of automotive LED drivers with the BCR4xxUQ series that simplifies the driving of low-power lighting. LED technology is displacing conventional bulbs throughout the car: from external lighting such as side markers, puddle lighting and sill plates, to internal lighting including dome, ambient lights, instrument clusters and button backlighting. The BCR4xxUQ series is designed to meet the needs of all these applications, providing a simple, low-profile and flexible approach to driving low-power LED strings.
Each of the devices in the BCR4xxUQ series can provide a pre-set current output without the need for any external components, or deliver an adjustable constant current between 10 mA and 100 mA (BCR401UQ, BCR402UQ, BCR405UQ), 200 mA (BCR420UQ), or 350 mA (BCR421UQ) with ±10% tolerance. All devices in the series are available in both industry-standard SOT26 and low-profile DFN2020 package options. The thinner 0.6 mm DFN2020 is designed for edge-lighting applications in which a less-intrusive, lower-height package is required. All devices include negative temperature coefficient, which lowers the LED driver current as the internal temperature rises, thereby protecting and extending the lifetime of the LEDs. In addition, the linear topology used means the devices exhibit virtually no EMI.
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| Internal Device Schematics: BCR401, BCR402, BCR405 (left); BCR420, BCR421 (right). |
With a wide operating voltage range of between 1.4 V and 40 V and total power dissipation of up to 1.7 W, the devices can be used to drive larger strings of LEDs while still providing sufficient protection from transients in a 12 V automotive supply system. The BCR421UQ has the advantage that it can be PWM dimmed directly from 3.3 V MCU signal with up to 25 kHz and a duty cycle of 1%.
